COPPER ALLOY

Description

TECHNICAL FIELD

[0001] The present invention relates to a copper alloy applicable as materials for electric and electronic instruments.

BACKGROUND ART

[0002] Heretofore, generally, in addition to iron-based materials, copper-based materials, such as phosphor bronze, red brass, and brass, which are excellent in electrical conductivity and thermal conductivity, have been used widely as materials for electric and electronic instruments (electrical and electronic machinery and tools).
Recently, demands for miniaturization, weight saving, and associated high-density packaging of parts of electric and electronic instruments have increased, and various characteristics of higher levels are required for the copper-based materials applied thereto. Examples of basic characteristics required include mechanical properties, electrical conductivity, stress relaxation resistance, bending property, and spring property. Of those, improvements in stress relaxation resistance, tensile strength, and bending property are strongly required, for satisfying the recent demands for the miniaturization of parts or components for the products described above. In particular, for miniaturizing electronic parts, for example, tensile strength and bending property are necessary for lead frame materials, while stress relaxation resistance as well as tensile strength is necessary for connectors and terminal materials.

[0003] The requirements for those materials differ form each other little by little, depending on uses, kinds, shapes, or the like of the parts, and specific requirements include: a tensile strength of 700 MPa or more and a bending property of R/t ≤ 1.0 (in which R represents a bending radius, and t represents a sheet thickness), or a tensile strength of 800 MPa or more and a bending property of R/t ≤ 2.0; more preferably a tensile strength of 800 MPa or more and a bending property of R/t < 1.5, or a tensile strength of 900 MPa or more and a bending property of R/t < 2.0.
Thinning of the material is inevitable in association with miniaturization of the parts. Accordingly, conventional copper alloys are not always durable to long term uses due to increased stress loaded on the material and increased temperatures of working environments. Under these situations, more improved stress relaxation resistance is desired. Minimum stress relaxation resistance is a value defined by the Standard of the Electronic Materials Manufacturers Association of Japan (EMAS-3003), wherein the copper alloy material is desired to satisfy a stress relaxation ratio of less than 20% at a temperature condition of 150°C.
The required characteristics have reached a level that cannot be satisfied with conventional commercially available, mass-produced alloys, such as phosphor bronze, red brass, and brass. Thus, conventionally, such alloys each have an increased strength by: allowing Sn or Zn having a very different atomic radius from that of copper as a matrix phase, to be contained as a solid solution in Cu; and subjecting the resultant alloy having the solid solution to cold-working such as rolling or drawing. The method can provide high-strength materials by employing a large cold-working ratio, but employment of a large cold-working ratio (generally 50% or more) is known to conspicuously degrade bending property of the resultant alloy material. The method generally involves a combination of solid solution strengthening and working strengthening.

[0004] An alternative strengthening method is a precipitation strengthening method (a precipitation hardening method) that involves formation of a precipitate of a nanometer order in the materials. The precipitation strengthening method has merits of increasing strength and improving electrical conductivity at the same time, and is used for many alloys.
Of those, a strengthened alloy prepared by forming a precipitate composed of Ni and Si by adding Ni and Si into Cu, so-called a Corson alloy, has a remarkably high strengthening ability compared with many other precipitation-type alloys. This strengthening method is also used for some commercially available alloys (e.g. CDA70250, a registered alloy of Copper Development Association (CDA)). When the alloy generally subjected to precipitating strengthening is used for terminal/connector materials, the alloy is produced through a production process incorporating the following two important heat treatments. One is a heat treatment which involves heat treatment at a high temperature (generally 700°C or higher) near a melting point, so-called solution treatment, to allow Ni and Si precipitated through casting or hot-rolling to be contained as a solid solution into a Cu matrix. The other is a heat treatment which involves heat treatment at a lower temperature than that of the solution treatment, so-called aging treatment, to precipitate Ni and Si, which are in the solid solution caused at the high temperature, as a precipitate. The strengthening method utilizes a difference in concentrations of Ni and Si entering Cu as a solid solution at high temperatures and low temperatures.

[0005] An example of the Corson alloy applicable for electric and electronic instruments includes an alloy having a defined grain size of precipitate (see, for example. EP 0 949 343, Patent Document 1). However, the precipitation-type alloy has such problems that the crystal grain size increases to cause giant crystal grains upon the solution treatment, and that the crystal grain size upon the solution treatment remains unchanged and becomes the crystal grain size of a product since the aging treatment generally does not involve recrystallization. An increased amount of Ni or Si to be added requires a solution treatment at a higher temperature, and it results in that the crystal grain size tends to increase to cause giant crystal grains, through a heat treatment in a short period of time. The resultant giant crystal grains occurred in this way cause problems of conspicuous deterioration in bending property.
Alternatively, a method of improving the bending property of a copper alloy involves addition of Mn, Ni, and P for a mutual reaction to precipitate a compound, without use of a Ni-Si precipitate (see, for example, Patent Document 2). However, the resultant alloy has a tensile strength of about 640 MPa at most, which is not sufficient for satisfying the recent demands for high strength through miniaturization of parts. Addition of Si to the copper alloy decreases the amount of the Ni-P precipitate, to thereby reduce the mechanical strength and electrical conductivity. Further, excess Si and P cause problems of occurrence of crack upon hot working.
As is apparent from the above, the bending property is hardly maintained with increasing tensile strength. Accordingly, it is desired to develop the copper alloy allowing tensile strength, bending property, electrical conductivity, and stress relaxation resistance to be compatible at high levels to one another or keeping a good balance among them, while these properties are able to be controlled depending on the uses.
Other and further features and advantages of the present invention will appear more fully from the following description.

[0006] 

Patent Document 1: JP-A-11-43731 ("JP-A" means unexamined published Japanese patent application)

Patent Document 2: JP-A-2003-82425

DISCLOSURE OF INVENTION

[0007] For solving the above-mentioned problems, the present invention contemplates providing a copper alloy having high bending property and excellent tensile strength, electrical conductivity and stress relaxation resistance, wherein characteristics of the copper alloy may be readily balanced depending on uses, and the copper alloy is favorable for materials of lead frames, connectors, terminals or the like of electric and electronic instruments, particularly for materials of vehicle connectors, terminals, relays and switches or the like.

[0008] The inventors of the present invention have conducted intensive studies on a copper alloy suitably used for electrical and electronic parts, and have noticed the relations between characteristics of the alloy and grain diameters of Ni-Si precipitates and other precipitates in a copper alloy structure, and between the proportions of the distribution density of the precipitates and suppression of coarsening of crystal grains. As a result, the inventors have completed, through intensive studies, the copper alloy of the present invention that is able to form a material having excellent tensile strength and being excellent in bending property, electrical conductivity, and stress relaxation resistance.
According to the present invention which is given in the claims, there is provided inter alia the following means:

(1) A copper alloy, having: a precipitate Y composed of Ni and/or Si, and at least one or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be; and a precipitate X composed of Ni and Si, wherein a grain diameter of the precipitate Y is 0.01 to 2 µm;

(2) The copper alloy, wherein the grain diameter of the precipitate Y is 0.02 to 0.9 µm;

(3) A copper alloy, having: a precipitate X composed of Ni and Si; and at least one precipitate selected from the group consisting of a precipitate Y1 composed of Ni, Si, and Cr, a precipitate Y2 composed of Ni, Si, and Co, a precipitate Y3 composed of Ni, Si, and Zr, and a precipitate Z composed of Ni, Si, and B, wherein a grain diameter of the at least one precipitate selected from the group consisting of the precipitates Y1, Y2, Y3, and Z is 0.1 to 2 µm;

(4) A copper alloy, comprising: Ni 2.0 to 5.0 mass%, Si 0.3 to 1.5 mass%, at least one or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be each in an amount of 0.005 to 1.0 mass%, with a balance being Cu and inevitable impurities; said copper alloy having a precipitate X composed of Ni and Si; and a precipitate Y composed of Ni, Si, and at least one or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be, wherein a grain diameter of the precipitate Y is 0.01 to 2 µm;

(5) A copper alloy, comprising: Ni 2.0 to 5.0 mass%, Si 0.3 to 1.5 mass%, at least one or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be each in an amount of 0.005 to 1.0 mass%, with a balance being Cu and inevitable impurities; said copper alloy having a precipitate X composed of Ni and Si; and a precipitate Y composed of Ni or Si, and at least two or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be, wherein a grain diameter of the precipitate Y is 0.01 to 2 µm;

(6) A copper alloy, comprising: Ni 2.0 to 5.0 mass%, Si 0.3 to 1.5 mass%, at least one or more selected from the group consisting of B, AI, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be each in an amount of 0.005 to 1.0 mass%, with a balance being Cu and inevitable impurities; said copper alloy having a precipitate X composed of Ni and Si; and a precipitate Y composed of at least three or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be, wherein a grain diameter of the precipitate Y is 0.01 to 2 µm:

(7) The copper alloy according to any one of (1) to (6), wherein the melting point of the precipitate Y is higher than a solid solution treatment temperature;

(8) The copper alloy according to any one of (1) to (7), wherein the number of precipitates X per mm² is 20 to 2,000 times the number of precipitates Y per mm²;

(9) The copper alloy according to any one of (1) to (8), wherein the number of precipitates X is 10⁸ to 10¹² per mm², and the number of precipitates Y is 10⁴ to 10⁸ per mm²;

(10) The copper alloy according to any one of (1) to (9), wherein a composition of the copper alloy further comprises at least one or more selected from Sn 0.1 to 1.0 mass%, Zn 0.1 to 1,0 mass%, and Mg 0.05 to 0.5 mass%;

(11) The copper alloy according to any one of (1) to (10), which has a stress relaxation ratio of less than 20%; and

(12) The copper alloy according to any one of (1) to (11), which is for use as a material of an electric or electronic instrument.

[0009] The copper alloy of the present invention which is given by the claims compatibly has a tensile strength and a bending property (R/t) at high levels, without impairing electrical conductivity, while stress relaxation resistance that may largely affect reliability of connectors and terminals is further improved. The copper alloy of the present invention is excellent in bending property and stress relaxation resistance, as compared with conventional copper alloys having the same level of tensile strength. The copper alloy of the present invention is a copper alloy favorable for use in electric and electronic instruments that are required for higher characteristics upon miniaturization. In addition to the above, the copper alloy of the present invention is excellent in other properties such as spring property.

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] Preferable embodiments of the copper alloy of the present invention will be described in detail.
The copper alloy of the present invention given by the claims is an inexpensive, high-performance copper alloy maintaining high electrical conductivity, having excellent bending property and other favorable properties, and it is preferable for a variety of electric and electronic instruments including electronic parts, e.g. vehicle terminals/connectors, relays, and switches.

[0011] Preferable embodiments of the copper alloy of the present invention will be described in detail.
The present invention relates to controlling of a grain size of a precipitate of a copper alloy. To be specific, a method of controlling a grain size has been realized from two standpoints.
First, the method of controlling a grain size can be realized by using an element that does not allow a crystal grain size to increase to cause giant grains upon a solution treatment. Each of precipitates composed of Ni, Si and α; Ni, α and β; Si, α and β; and α, β and γ (herein α, β and γ each are an element other than Ni and Si) does not form any solid solution in a Cu matrix phase even at high temperatures of the solution treatment, and that the precipitate exists in crystal grains of the Cu matrix phase and the precipitate grains, to exhibit an action and effect of suppressing growth of the crystal grains of the matrix.

[0012] Second, the method of controlling a grain size can be realized by using an element that serves as a nucleus at initial recrystallization upon the solution treatment. An intermetallic compound which is a precipitate composed of Ni, Si and α; Ni, α and β; Si, α and β; and α, β and γ (herein α, β and γ each are an element other than Ni and Si) serves as a nucleation site for recrystallization at a solution treatment temperature, and that more crystal grains are formed (nucleation) than that in the case where the precipitate is not added. Formation of more crystal grains causes mutual interference of the crystal grains during grain growth, to thereby suppress the grain growth. Multi-component precipitates are preferable for the action and effect of the nucleation site for recrystallization.
In the present invention, the term "precipitate" means to include intermetallic compounds, carbides, oxides, sulfides, nitride, compounds (solid solutions), and element metals.

[0013] The aforementioned precipitate is not to form any solid solution in the Cu matrix even during the solution treatment. That is, the precipitate must have a melting point higher than the solution treatment temperature. The precipitate is not limited to the aforementioned precipitates as long as it has a melting point higher than the solution treatment temperature. Further, the precipitate is not limited as long as it provides an effect of preventing growth of too large crystal grains during the solution treatment or forming many crystal grains (nucleation) by serving as a nucleation site for recrystallization.
The copper alloy of the present invention is an inexpensive, high-performance copper alloy maintaining high electrical conductivity, having excellent bending property and other favorable properties, and it is preferable for a variety of electric and electronic instruments including electronic parts, e.g. vehicle terminals/connectors, relays, and switches.

[0014] Next, the alloy structure of the copper alloy will be described.
The grain diameter of the precipitate X composed of Ni and Si is preferably 0.001 to 0.1 µm, more preferably from 0.003 to 0.05 µm, and further preferably 0.005 to 0.02 µm. The strength is not improved when the grain diameter is too small, while the bending property decreases when the grain diameter is too large.

[0015] The precipitate Y composed of Ni and/or Si and at least one or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co and Be; the precipitate Y1 composed of Ni, Si and Cr; the precipitate Y2 composed of Ni, Si and Co; and the precipitate Y3 composed of Ni, Si and Zr each have larger effects for fining crystal grains than Ni-Si precipitate X does, during the solid solution treatment as a heat treatment at high temperatures. Those effects become particularly large by the precipitate Y1 and the precipitate Y2.
This effect acts for improving bending property. Since solid solution treatment can be applied at higher temperatures than temperatures of the conventional solid solution treatment, this effect can contribute to improvements of the tensile strength and the stress relaxation resistance by increasing the amount of the solid solution in the copper alloy as well as the amount of precipitates during aging treatments. This effect is particularly enhanced when the melting point of precipitate Y is higher than the melting point of precipitate X. The melting point of precipitate X is preferably from 650 to 1,050°C, and the melting point of precipitate Y is preferably higher than the melting point of precipitate X and 1,100°C or less.

[0016] The grain diameter of precipitate Y is 0.01 to 2.0 µm, preferably 0.05 to 0.5 µm, and more preferably from 0.05 to 0.13 µm. This is because an effect for suppressing growth of crystal grains and an effect for increasing the number of nucleation sites are not exhibited when the grain diameter is too small, while the bending property decreases when the grain diameter is too large. In the present invention, the grain diameter of precipitate Y is preferably larger than the grain diameter of precipitate X. The ratio of the grain diameters between Y and X (Y/X) preferably exceeds 1 and 2,000 or less, more preferably 5 to 500.

[0017] Next, the action and effect of each alloy element and a range of addition amount of the alloy element will be described.
Ni and Si are elements that are added in a controlled addition ratio of Ni to Si for forming a Ni-Si precipitate for precipitation strengthening, to thereby enhance the mechanical strength of the copper alloy. The amount of Ni to be added is generally 2.0 to 5.0 mass%, preferably 2.1 to 4.6 mass%. The Ni amount is more preferably 3.5 to 4.6 mass%, for satisfying a tensile strength of 800 MPa or more and a bending property of R/t < 1.5, or a tensile strength of 900 MPa or more and a bending property of R/t < 2. A too small Ni amount provides a small precipitated and hardened amount that results in insufficient mechanical strength, and a too large Ni amount results in a conspicuously low electrical conductivity.
Further, the ratio of the addition amount of Ni to Si of about 1 to 4 (i.e. the amount of Ni to be added being 4 vs. that of Si being about 1) in terms of mass ratio, is known to provide the largest strengthening effect. When the Si addition amount exceeds 1.5 mass%, it is apt to cause cracking of an ingot of the copper alloy during hot working. Thus, the Si addition amount is generally 0.3 to 1.5 mass%, preferably 0.5 to 1.1 mass%, more preferably 0.8 to 1.1 mass%.

[0018] B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be form precipitate Y by themselves or in combination with Ni and/or Si. While precipitate Y serves for suppressing crystal grains from coarsening during the solid solution treatment as described above, it is not responsible for or does not largely contribute to precipitation strengthening. The content of each of the above-mentioned elements is generally 0.005 to 1.0 mass%, preferably 0.007 to 0.5 mass%, and more preferably 0.01 to 0.1 mass%. The quality of an ingot is impaired by forming large crystals during melt-casting when the amount of addition of these elements is too large, while attainment of desired effects is impossible when the amount is too small.

[0019] Further, in particularly, Cr, Co and Zr form precipitates in combination with main components, Ni and Si. While the effect is to suppress crystal grains from being coarsened during the solid solution treatment, to thereby control the crystal grain diameter as described above, it does not largely contribute to precipitation strengthening. The amount of addition of these elements is preferably 0.005 to 1.0 mass%, more preferably 0.1 to 0.3 mass% for permitting the effect to be exhibited. The quality of the ingot may be impaired by forming large crystals during melt-casting when the amount of addition of these elements is too large, while the effect of addition is not exhibited when the amount is too small.

[0020] B forms a precipitate with main constituents Ni and Si. The effect of B as the same manner as the above Cr, Co or Zr is that B is an element for suppressing increase of the crystal grain size to become too large (giant) during the solution treatment, but B takes no part in the precipitation strengthening. The B addition amount is preferably 0.005 to 0.1 mass%, more preferably 0.01 to 0.07 mass%, for exhibiting the effect. A too large B addition amount results in too large crystallized product during melt-casting to cause problems in ingot quality, and a too small B addition amount provides no addition effect.

[0021] Further, Zn, Sn, and/or Mg are preferably added to further improve the characteristics.
Zn is an element which forms a solid solution in a matrix, but Zn addition significantly alleviates solder embrittlement. Thus, Zn is added preferably in an amount of 0.1 to 1.0 mass%. The preferable primary uses of the alloy of the present invention are electric and electronic instruments and electronic part terminal materials such as vehicle terminals/connectors, relays, and switches. Most of them are joined by solder, and thus the enhancement of reliability in the joined portions is one of the important elemental techniques.
Further, Zn addition may lower the melting point of the alloy, to control the states of formation of the precipitate composed of Ni and B and the precipitate composed of Mn and P. Both the precipitates are formed during solidification. Thus, a high solidification temperature of the alloy increases the grain size, to provide a small contribution of the precipitates to the effects of suppressing increase of the crystal grain size and forming a nucleation site for the crystal grains. The lower limit of Zn addition is defined as 0.1 mass%, because it is a minimum necessary amount that provides alleviations in solder embrittlement. The upper limit of Zn addition is defined as 1.0 mass%, because a Zn addition amount more than 1.0 mass% may degrade the electrical conductivity.

[0022] Sn and Mg to be added are also preferable elements for their uses. Sn and Mg addition provides an effect of improving creep resistance, which is emphasized in electronic instrument terminals/connectors. The effect is also referred to as stress relaxing resistance, and it is an important characteristic that assumes reliability of the terminals/connectors. Solely addition of Sn or Mg may improve the creep resistance, but the use in combination of Sn and Mg can further improve the creep resistance by a synergetic effect. The lower limit of Sn addition is defined as 0.1 mass%, because it is a minimum necessary amount that provides improvements in creep resistance. The upper limit of Sn addition is defined as 1 mass%, because a Sn addition amount more than 1 mass% may degrade the electrical conductivity. The lower limit of Mg addition is defined as 0.05 mass%, because an addition amount of Mg less than 0.05 mass% provides no effect of improving the creep resistance. The upper limit of Mg addition is defined as 0.5 mass%, because an Mg addition amount of more than 0.5 mass% not only saturates the effect. Further, when an Mg addition amount is more than 0.5 mass%, it may degrade hot-workability at a particularly-high temperature, depending on the composition of the alloy.
Sn and Mg have a function of accelerating formation of a precipitate composed of Ni and Si. It is important to add preferable amounts of these Sn and Mg, serving as fine nucleation sites for the precipitate.

[0023] Next, the relationship between the number of precipitate X (the number of grains of the precipitate X) and the number of precipitate Y as another precipitate will be described below.
The number of precipitate X per mm² on an arbitrary cross section in the copper alloy is 20 to 2,000 times the number of corresponding precipitate Y per mm². This is because the bending property is particularly enhanced among the characteristics, and a sufficient mechanical strength can be obtained. The number of the precipitate X is preferably 100 to 1,500 times the number of the precipitate Y

[0024] Specifically, the number of precipitates X is preferably 10⁸ to 10¹² per mm², and the number of precipitates Y that correspond to the precipitates X is preferably 10⁴ to 10⁸ per mm². This is because the aforementioned ranges provide particularly excellent bending property. If the number of precipitates is too small, the resultant alloy may not have a targeted mechanical strength. On the other hand, if the number of precipitates is too large, the resultant alloy may be poor in bending property. The number of precipitates X is more preferably 5×10⁹ to 6×10¹¹ per mm², and the number of precipitates Y is more preferably 10⁴ to 4×10⁷ per mm².
The effect of precipitates becomes remarkable as the amounts of Ni and Si are increased. A tensile strength of 800 MPa or more with the bending property of R/t ≤ 2.0, or a tensile strength of 700 MPa or more with the bending property of R/t ≤ 1.0 may be attained, by controlling the number of precipitates Y as described above. It is also possible to attain a tensile strength of 800 MPa or more with the bending property of R/t < 1.5, or a tensile strength of 900 MPa or more with the bending property of R/t < 2. With respect to the stress relaxation resistance, the stress relaxation ratio of the copper alloy is preferably less than 20%, more preferably less than 18%, and further preferably 15% or less, in which an open-sided block method prescribed in the Standard of the Electronic Materials Manufacturers Association of Japan (EMAS-3003) is employed with load stress set to be a surface maximum stress of 80%-yield strength (80%-YS, 0.2%-proof stress), and the stress relaxation ratio is measured under the conditions of at 150°C for 1,000 hours. The number of precipitates is represented by an average number per unit area.

[0025] The copper alloy of the present invention may have a crystal grain diameter (i.e. an average of a minor axis diameter and a major axis diameter) of generally 20 µm or less, preferably 10.0 µm or less. If the crystal grain diameter is longer than 10.0 µm, it may be impossible to obtain a tensile strength of 720 MPa or more and a bending property of R/t < 2. More preferably, the crystal grain diameter of the copper alloy is 8.5 µm or less. The lower limit of the crystal grain diameter may be generally 0.5 µm or more. The aforementioned crystal grain diameters are measured in the following manner: The crystal grain diameters are measured in two directions parallel to or perpendicular to the finally cold-rolled direction, respectively, on cross sections parallel to the direction of thickness of the alloy sheet and parallel to the finally cold-rolled direction (the direction of the final plastic-working), thereby to determine larger lengths as major axis diameters and smaller lengths as minor axis diameters in respective directions. An average value of each four lengths of the major axis diameters and minor axis diameters is rounded up as a product of multiplying 0.005 mm times an integer, to determine the crystal grain diameter.

[0026] Next, a specific example of a preferable production method for the copper alloy according to the present invention involves: melting a copper alloy having the aforementioned element composition; casting into an ingot; and hot-rolling the ingot. More specifically, the production method involves: heating the ingot at a temperature rising rate of 20 to 200°C/hr; holding the resultant ingot at 850 to 1,050°C for 0.5 to 5 hours; hot-rolling; and, after finishing the hot-rolling at a finishing temperature of 300 to 700°C, quenching the hot-rolled product. In this way, the precipitate X, and the precipitate Y corresponding to the element composition are formed. After hot-rolling, for example, the resultant alloy is formed into a given thickness, through a combination of solution treatment, annealing, and cold-rolling.
The purpose of the solution treatment is to allow Ni and Si precipitated during casting or hot-rolling, to form a solid solution again and to recrystallize at the same time. This permits the amount of the elements in the solid solution to be increased and accumulated distortion during working to be removed, and a basic treatment for improving the strength and bending property can be provided. The temperature of the solution treatment may be adjusted according to a Ni addition amount. As preferable embodiments, the solution treatment temperature is preferably 600 to 820°C for an Ni amount of 2.0 mass% or more but less than 2.5 mass%, 700 to 870°C for an Ni amount of 2.5 mass% or more but less than 3.0 mass%, 750 to 920°C for an Ni amount of 3.0 mass% or more but less than 3.5 mass%, 800 to 970°C for an Ni amount of 3.5 mass% or more but less than 4.0 mass%, 850 to 1,020°C for an Ni amount of 4.0 mass% or more but less than 4.5 mass%, and 920 to 1,050°C for an Ni amount of from 4.5 mass% or more but less than 5.0 mass%. Since crystal grains are suppressed from being coarsened at high temperatures in the alloy of the present invention to which the above-mentioned elements are added, the amount of elements in the solid solution is increased by applying the solid solution treatment at higher temperatures, to thereby enable a high strength to be obtained.

[0027] For example, the heat treatment at 900°C of an alloy material composed of Ni 3.0 mass% and Si 0.7 mass%, allows sufficient Ni-Si precipitates that have already been precipitated, to form again the solid solution. However, the size of the crystal grain far exceeds 10 µm, and the bending property is conspicuously decreased. However, crystal grains with a size of 10 µm or less may be obtained, even by a solid solution treatment at 900°C, from an alloy material to which any one of Cr, Co, Zr, and B is further added.
Further, for example, the heat treatment at 850°C of an alloy material whose Ni content is 3.0 mass% and Si content is 0.7 mass%, allows sufficiently precipitated Ni and Si, to form again the solid solution and thereby to give crystal grains of 10 µm or less. However, the heat treatment at the same temperature of an alloy having a too small Ni amount causes growth of crystal grains into too large grains to thereby fail in obtaining a grain size of 10 µm or less. Further, on the other hand, a too large Ni amount may not provide an ideal solution state, and the mechanical strength may not be enhanced through the subsequent aging treatment.
The size of the precipitate (e.g. precipitate Y) may be changed, by changing the conditions of the solid solution treatment, i.e. by appropriately selecting the temperature of the solid solution treatment, as described above. For example, a higher temperature of the solid solution treatment (a temperature higher by 50°C than a standard temperature) is selected for the heat treatment when the size of precipitate Y1 is to be increased, while a lower temperature of solid solution treatment (a temperature lower by 50°C than a standard temperature) is selected for the heat treatment when the size of precipitate Y1 is to be decreased. In addition, the change of the density is coupled with the change of the crystal grain size, and the density becomes lower as the size is larger, while the density becomes higher as the size is smaller.

[0028] The copper alloy of the present invention as claimed apparently provides improvement in, in particular, bending property, and optionally stress relaxation resistance, of a high strength copper alloy having a tensile strength of 800 MPa or more, while high electrical conductivity is maintained. Further, the copper alloy of the present invention provides similar improvement in bending property of a copper alloy having a tensile strength of less than 800 MPa. The copper alloy according to the present invention is also excellent in other properties, such as spring property and the like.

EXAMPLES

[0029] The present invention will be described in more detail based on examples given below, but the invention is not meant to be limited by these.

(Example 1)

[0030] An alloy component containing Ni, Si, Cr, and other elements in the amounts, as shown in Table 1, with the balance being Cu and inevitable impurities, was melted with a high frequency melting furnace, and the thus-molten alloy was cast at a cooling rate from 10 to 30 °C/second, to give an ingot with a size: thickness 30 mm, width 100 mm, and length 150 mm. After holding the ingot at 900°C for 1 hour, the resultant ingot was subjected to hot-rolling, to give a hot-rolled sheet with a sheet thickness (t) of 12 mm, each of the surfaces of the sheet was chamfered by 1 mm, to adjust the thickness (t) at 10 mm, and then the sheet was finished at a thickness (t) of 0.167 mm by cold-rolling. The sheet material was then subjected to solid solution treatment. The temperature of the solid solution treatment was selected, in accordance with the conditions described in the foregoing paragraph [0026]. For changing the size of precipitate Y1, a higher solid solution treatment temperature (a temperature higher by 50°C than a standard temperature) was selected when the size of precipitate Y1 was to be increased, while a lower solid solution temperature (a temperature lower by 50°C than a standard temperature) was selected when the size of precipitate Y1 was to be decreased, for conducting the heat treatment. The change of the density was coupled with the change of the crystal grain size, and the density became lower as the size was larger, while the density became higher as the size was smaller.
Immediately after the solution treatment, the sheet material was subjected to water quenching. Then, each of the resultant alloys was subjected to aging at a temperature of 450 to 500°C for 2 hours and cold-rolling with a working ratio of 10%, to thereby obtain a sample of t = 0.15 mm.

[0031] The following characteristics of the thus-obtained samples were tested and evaluated as mentioned in below, and the results are shown in Table 2.

a. Electrical conductivity (EC):

[0032] Electrical conductivity was calculated by measuring a specific resistance of the sample through a four terminal method in a thermostatic bath maintained at 20°C (±0.5°C). The distance between the terminals was set to 100 mm.

b. Tensile strength (TS):

[0033] Tensile strengths of 3 test pieces prepared according to JIS Z 2201-13B cut out from the sample in a direction parallel to the rolling direction, were measured according to JIS Z 2241, and an average value thereof was obtained.

c. Bending property:

[0034] A test piece was cut out from the sample in a direction parallel to the rolling direction into a size of width 10 mm and length 25 mm. The resultant test piece was W-bent at 90° at a bending radius R that would be 0, 0.1, 0.15, 0.2, 0.25, 0.3, 0.4, 0.5, or 0.6 (mm), with a bending axis being perpendicular to the rolling direction. Whether cracks were occurred or not at the bent portion, was observed with the naked eye through observation with an optical microscope of 50 times magnification, and the bent sites were observed with a scanning electron microscope to examine whether cracks were observed or not. Evaluation results are designated by R/t (in which R represents a bending radius (mm), and t represents a sheet thickness(mm)), and the R/t was calculated by employing a (limit) maximum R at which cracks were occurred. If no crack is formed at R = 0.15 and cracks are formed at R = 0.1, since the sample had a thickness (t) = 0.15 mm, R/t = 0.15/0.15 = 1 is obtained, which is shown in the following table. As the value of R/t is smaller, the bending property is improved.

d. Grain size of precipitate and distribution density:

[0035] The sample was punched out into a shape of a disc of diameter 3 mm, and the resultant was subjected to thin-film-polishing by using a twinjet polishing method. Photographs (5,000 and 100,000 times magnification) of the resultant sample were taken at 3 arbitrary positions with a transmission electron microscope at accelerating voltage 300 kV, and the grain size of the precipitate and the density thereof were measured on the photographs. Measurement of the grain size and density of the precipitate were carried out in the following manner: setting an incident electron beam azimuth to [001], and measuring the number of fine grains of the precipitate X composed of Ni-Si in a high-power photograph (100,000 times magnification) at n = 100 (n represents the number of viewing fields for observation), since the precipitate X was fine; and, on the other hand, measuring the number of grains of the precipitate Y1 in a low-power photograph (5,000 times magnification) at n = 10; thereby to eliminate the localized bias on the numbers. The numbers were calculated into numbers per unit area (/mm²). e. Crystal grain diameter:
The crystal grain diameter was measured according to JIS H 0501 (cutting method). The crystal grain diameters were measured in two directions parallel to and perpendicular to the finally cold-rolled direction, respectively, on cross sections parallel to the direction of thickness of the alloy sheet and parallel to the finally cold-rolled direction (the direction of the final plastic-working). The thus-measured lengths were classified into larger lengths as major axis diameters and smaller lengths as minor axis diameters in respective directions. An average value of each four lengths of the major axis diameters and minor axis diameters was rounded up as a product of multiplying 0.005 mm times an integer, to determine the crystal grain diameter.

[Table 1]

[0036] 

Table 1

Classification	No.	Ni [mass%]	Si [mass%]	Cr [mass%]	Other [mass%]
Example according to this invention	1	2.31	0.52	0.08	-
	2	3.22	0.73	0.62	-
	3	3.82	0.86	0.19	Zn:0.51
	4	4.22	0.95	0.22	Zn:0.49
					Sn:0.15
					Mg:0.11
	5	4.81	1.09	0.41	Zn:0.50
					Sn:0.12
Comparative example	100	2.37	0.56	0.09	-
	101	3.35	0.80	0.13	-
	102	3.94	0.94	0.19	Zn:0.52
					Sn:0.15
	103	4.29	1.02	0.22	-

[Table 2]

[0037] 

Table 2

Classification	No.	Grain size of precipitate X [µm]	Grain size of precipitate Y1 [µm]	Number of Y1/ number of X	Crystal grain diameter [µm]	TS [MPa]	EC [%IACS]	Bending property [R/t]
Example according to this invention	1	0.02	0.21	330	5	722	44	1.0
	2	0.03	0.19	430	6	764	40	1.0
	3	0.05	0.22	58	8	805	38	1.5
	4	0.04	0.17	890	7	846	36	2.0
	5	0.04	0.19	1020	5	887	33	2.0
Comparative example	100	0.02	2.20	19	18	725	44	1.5
	101	0.03	0.001	16	22	764	41	2.5
	102	0.03	0.004	18	19	803	39	3.0
	103	0.04	2.92	10	27	841	36	3.5

[0038] From the results shown in Tables 1 and 2, it is understood that the samples according to the present invention have excellent properties in both of the mechanical strength and the bending property. However, since the grain diameter of precipitate Y1 was outside of the range defined in the present invention, the samples in Comparative examples 100, 101, 102 and 103 each were poor in the bending property, as compared with the samples in the examples according to the present invention having the same level of mechanical strength, and the mechanical strength in the comparative examples was not compatible to the bending property. Thus, it is possible to improve the bending property (R/t) while high strength is maintained, by controlling the grain diameter of precipitate Y1 in the Cu alloy system containing Ni, Si, and Cr. Based on the above, the copper alloys of the examples according to the present invention can be considered to be favorable for materials of lead frames or the like. Further, the copper alloys of the examples according to the present invention are also excellent in other properties, such as spring property.

(Example 2)

[0039] With respect to the copper alloys containing the elements in the amounts, as shown in Table 3, with the balance being made of Cu and inevitable impurities, the test was conducted in the same manner as in Example 1, except that the measurement was made on the precipitate Y2 in place of the precipitate Y1. The results are shown in Table 4. The production and measurement methods were also performed in the same manner as in Example 1.

[Table 3]

[0040] 

Table 3

Classification	No.	Ni [mass%]	Si [mass%]	Co [mass%]	Other [mass%]
Example according to this invention	6	2.33	0.48	0.09	-
	7	3.20	0.67	0.55	-
	8	3.84	0.93	0.17	Zn:0.51
	9	4.29	1.02	0.14	Zn:0.49
					Sn:0.15
					Mg:0.12
	10	4.82	1.09	0.37	Zn:0.50
					Sn:0.12
Comparative example	105	2.40	0.52	0.04	-
	106	3.26	0.77	0.19	-
	107	3.94	0.86	0.19	Zn:0.52
					Sn:0.15
	108	4.32	1.00	0.31	-

[Table 4]

[0041] 

Table 4

Classification	No.	Grain size of precipitate X [µm]	Grain size of precipitate Y2 [µm]	Number of Y2/ number of X	Crystal grain diameter [µm]	TS [MPa]	EC [%IACS]	Bending property [R/t]
Example according to this invention	6	0.016	0.209	331	6	718	45	1.0
	7	0.021	0.189	442	6	759	40	1.0
	8	0.045	0.212	60	9	805	38	1.5
	9	0.034	0.170	902	7	843	37	2.0
	10	0.041	0.195	1035	5	877	34	2.0
Comparative example	105	0.021	2.150	34	19	723	44	1.5
	106	0.031	0.009	19	22	763	41	2.5
	107	0.029	0.005	19	20	799	39	3.0
	108	0.047	2.918	17	27	830	36	3.5

[0042] From the results shown in Tables 3 and 4, it is understood that the samples according to the present invention have excellent properties in both of the mechanical strength and the bending property. However, since the grain diameter of precipitate Y2 was outside of the range defined in the present invention, the samples in Comparative examples 105, 106, 107 and 108 each were poor in the bending property, as compared with the samples in the examples according to the present invention having the same level of mechanical strength, and the mechanical strength in the comparative examples was not compatible to the bending property. Thus, it is possible to improve the bending property (R/t) while high strength is maintained, by controlling the grain diameter of precipitate Y2 in the Cu alloy system containing Ni, Si, and Co. Based on the above, the copper alloys of the examples according to the present invention can be considered to be favorable for materials of lead frames or the like. Further, the copper alloys of the examples according to the present invention are also excellent in other properties, such as spring property.

(Example 3)

[0043] With respect to the copper alloys containing the elements in the amounts, as shown in Table 5, with the balance being made of Cu and inevitable impurities, the test was conducted in the same manner as in Example 1, except that the measurement was made on the precipitate Y3 in place of the precipitate Y1. The results are shown in Table 6. The production and measurement methods were also performed in the same manner as in Example 1.

[Table 5]

[0044] 

Table 5

Classification	No.	Ni [mass%]	Si [mass%]	Zr [mass%]	Other [mass%]
Example according to this invention	11	2.42	0.59	0.07	-
	12	3.18	0.84	0.69	-
	13	3.81	0.79	0.21	Zn:0.51
	14	4.31	1.01	0.30	Zn:0.49
					Sn:0.14
					Mg:0.10
	15	4.77	1.08	0.36	Zn:0.50
					Sn:0.13
Comparative example	109	2.30	0.63	0.06	-
	110	3.28	0.83	0.15	-
	111	3.90	0.78	0.20	Zn:0.53
					Sn:0.15
	112	4.37	1.08	0.18	-

[Table 6]

[0045] 

Table 6

Classification	No.	Grain size of precipitate X [µm]	Grain size of precipitate Y3 [µm]	Number of Y3/number of X	Crystal grain diameter [µm]	TS [MPa]	EC [%IACS]	Bending property [R/t]
Example according to this invention	11	0.022	0.204	361	7	709	45	1.0
	12	0.021	0.195	448	7	747	42	1.0
	13	0.050	0.225	80	9	802	39	1.5
	14	0.035	0.174	916	8	835	37	2.0
	15	0.046	0.181	1048	5	875	33	2.0
Comparative example	109	0.021	2.250	43	19	715	45	1.5
	110	0.031	0.009	19	23	751	42	2.5
	111	0.038	0.004	28	20	796	40	3.0
	112	0.036	2.929	52	28	828	38	3.5

[0046] From the results shown in Tables 5 and 6, it is understood that the samples according to the present invention have excellent properties in both of the mechanical strength and the bending property. However, since the grain diameter of precipitate Y3 was outside of the range defined in the present invention, the samples in Comparative examples 109, 110, 111 and 112 each were poor in the bending property, as compared with the samples in the examples according to the present invention having the same level of mechanical strength, and the mechanical strength in the comparative examples was not compatible to the bending property. Thus, it is possible to improve the bending property (R/t) while high strength is maintained, by controlling the grain diameter of precipitate Y3 in the Cu alloy system containing Ni, Si, and Zr. Based on the above, the copper alloys of the examples according to the present invention can be considered to be favorable for materials of lead frames or the like. Further, the copper alloys of the examples according to the present invention are also excellent in other properties, such as spring property.

(Example 4)

[0047] With respect to the copper alloys containing the elements in the amounts, as shown in Table 7, with the balance being made of Cu and inevitable impurities, the test was conducted in the same manner as in Example 1, except that the measurement was made on the precipitate Z in place of the precipitate Y1. The results are shown in Table 8. The production and measurement methods were also performed in the same manner as in Example 1.

[Table 7]

[0048] 

Table 7

Classification	No.	Ni [mass%]	Si [mass%]	B [mass%]	Other [mass%]
Example according to this invention	16	2.36	0.38	0.08	-
	17	3.20	0.78	0.01	-
	18	3.87	0.86	0.10	Zn:0.50
	19	4.21	0.77	0.29	Zn:0.49
					Sn:0.15
					Mg:0.11
	20	4.95	1.11	0.21	Zn:0.48
					Sn:0.13
Comparative example	113	2.44	0.59	0.21	-
	114	3.43	0.86	0.02	-
	115	3.91	0.92	0.18	Zn:0.50
					Sn:0.15
	116	4.31	0.89	0.08	-

[Table 8]

[0049] 

Table 8

Classification	No.	Grain size of precipitate X [µm]	Grain size of precipitate Z [µm]	Number of Z/ number of X	Crystal grain diameter [µm]	TS [MPa]	EC [% IACS]	Bending property [R/t]
Example according to this invention	15	0.016	0.210	348	7	707	45	1.0
	16	0.023	0.187	441	8	743	41	1.0
	17	0.044	0.232	106	9	802	39	1.5
	18	0.036	0.170	921	9	829	36	2.0
	19	0.045	0.192	1054	6	870	34	2.0
Comparative example	113	0.021	2.250	59	20	712	46	1.5
	114	0.030	0.007	42	23	750	43	2.5
	115	0.042	0.003	38	20	790	40	3.0
	116	0.037	2.931	61	28	820	38	3.5

[0050] From the results shown in Tables 7 and 8, it is understood that the samples according to the present invention have excellent properties in both of the mechanical strength and the bending property. However, since the grain diameter of precipitate Z was outside of the range defined in the present invention, the samples in Comparative examples 113, 114, 115 and 116 each were poor in the bending property, as compared with the samples in the examples according to the present invention having the same level of mechanical strength, and the mechanical strength in the comparative examples was not compatible to the bending property. Thus, it is possible to improve the bending property (R/t) while high strength is maintained, by controlling the grain diameter of precipitate Z in the Cu alloy containing Ni, Si, and B. Based on the above, the copper alloys of the examples according to the present invention can be considered to be favorable for materials of lead frames or the like. Further, the copper alloys of the examples according to the present invention are also excellent in other properties, such as spring property.

(Example 5)

[0051] With respect to the copper alloys containing the elements in the amounts, as shown in Table 9, with the balance being made of Cu and inevitable impurities, the test was conducted in the same manner as in Example 1, except that the measurement was made on the precipitate Y2, Y3 or Z in place of a part of the precipitate Y1. The results are shown in Table 10. The production and measurement methods were also performed in the same manner as in Example 1.

[Table 9]

[0052] 

Table 9

Classification	No.	Ni [mass%]	Si [mass%]	Cr, Co, Zr, B [mass%]	Zn [masts%]	Sn [mass%]	Mg [mass%]
Example according to this invention	21	2.25	0.54	Cr: 0.08	0.2	0.10	0.20
	22	3.24	0.78	Co:0.08	0.3	0.15	0.15
	23	3.45	0.83	Cr: 0.2	0.5	0.10	0.10
				Zr: 0.1
	24	3.66	0.88	Zr: 0.1	0.5	0.12	0.12
				B: 0.02
	25	3.87	0.93	Cr: 0.7	0.4	0.15	0.15
	26	4.02	0.97	Cr: 0.2	0.2	0.18	0.11
				Co: 0.1
	27	4.27	1.02	Co: 0.8	0.5	0.22	0.21
				Zr: 0.1
	28	4.48	1.07	Cr: 04	0.4	0.40	0.15
	29	4.94	1.18	Cr: 0.3	0.5	0.32	0.14
				Co: 0.1
Comparative example	117	2.44	0.59	Cr: 0.09	0.4	0.25	0.12
	118	3.20	0.77	Co:0.25	0.5	0.15	0.17
	119	3.77	0.91	Zr: 0.2	0.2	0.20	0.09
				Cr: 0.1
	120	3.94	0.95	Cr:0.25	0.2	0.15	0.21
	121	4.23	1.01	Cr: 0.3	0.3	0.12	0.14
				Co: 0.1
	122	4.70	1.13	Cr: 0.25	0.4	0.20	0.21

[Table 10]

[0053] 

Table 10

Classification	No.	Grain size of precipitate X [µm]	Grain size of precipitate Y1, Y2, Y3, Z [µm]	Number of Y1, Y2, Y3, Z/ number of X	Crystal grain diameter [µm]	TS [MPa]	EC [%IACS]	Bending property [R/t]
Example according to this invention	21	0.023	0.204	333	6	705	44	1.0
	22	0.032	0.191	444	6	727	39	1.0
	23	0.051	0.223	80	9	728	37	1.0
	24	0.039	0.163	891	8	801	36	1.5
	25	0.045	0.195	1031	5	809	34	1.5
	26	0.018	0.208	365	6	811	33	2.0
	27	0.031	0.197	443	8	833	31	2.0
	28	0.053	0.219	94	9	854	30	2.0
	29	0.036	0.166	914	8	875	28	2.0
Comparative example	117	0.021	2.270	21	19	765	43	1.5
	118	0.031	0.006	23	23	786	39	2.0
	119	0.304	2.103	26	23	807	35	2.5
	120	0.044	0.001	28	20	828	33	3.0
	121	0.032	0.008	35	20	850	31	3.0
	122	0.047	2.916	26	28	871	27	3.0

[0054] From the results shown in Tables 9 and 10, it is understood that the samples according to the present invention have excellent properties in both of the mechanical strength and the bending property. However, since the grain diameter of precipitate Y1, Y2, Y3 or Z was outside of the range defined in the present invention, the samples in Comparative examples 117, 118, 119, 120, 121 and 122 each were poor in the bending property, as compared with the samples in the examples according to the present invention having the same level of mechanical strength, and the mechanical strength in the comparative examples was not compatible to the bending property. Thus, it is possible to improve the bending property (R/t) while high strength is maintained, by controlling the grain diameter of precipitate Y1 or the like. Based on the above, the copper alloys of the examples according to the present invention can be considered to be favorable for materials of lead frames or the like. Further, the copper alloys of the examples according to the present invention are also excellent in other properties, such as spring property.

[0055] In the following examples, it is shown that it is possible to control the stress relaxation resistance that has a large influence on the reliability particularly of connectors and terminal materials, by controlling the grain diameter of precipitate Y. While the copper alloys in the following examples according to the present invention are particularly favorable as connectors and terminal materials, they are also applicable to other uses, such as lead frame materials.

(Example 6)

[0056] With respect to the copper alloys containing Ni, Si, and elements in the given amounts as shown in Table 11, with the balance being made of Cu and inevitable impurities, the test was conducted in the same manner as in Example 1. The contents of Ni and Si were as follows: 3.5 mass% of Ni and 0.8 mass% of Si in the samples of Examples according to the present invention Nos. 1-4 and 1-11; 4.0 mass% of Ni and 0.95 mass% of Si in the sample of Example according to the present invention No. 1-6; and 3.8 mass% of Ni and 0.86 mass% of Si in the samples of other Examples according to the present invention and Comparative examples. The production and measurement methods for the samples were also performed in the same manner as in Example 1. Further, the stress relaxation resistance was evaluated by the following manner.

f. Stress relaxation resistance:

[0057] An open-sided block method prescribed in the Standard of the Electronic Materials Manufacturers Association of Japan (EMAS-3003) was employed with load stress set to be a surface maximum stress of 80%-yield strength (80%-YS, 0.2%-proof stress), and the stress relaxation ratio (S.R.R.) was measured by placing the sample in a thermostat bath at 150 °C for 1,000 hours. When the stress relaxation ratio of the copper alloy was less than 20%, it is judged that the stress relaxation resistance is "good", while when the S.R.R. was 20% or more, it is judged that the stress relaxation resistance is "poor".

[0058] Herein, the terms 'GW' and 'BW' in the following tables are defined as follows. GW denotes bending with a bend axis perpendicular to the direction of rolling, by using a test piece sampled in parallel to the direction of rolling; and BW denotes bending with a bend axis parallel to the direction of rolling, by using a test piece sampled perpendicular to the direction of rolling. In other words, GW means that the longitudinal direction of the test piece is parallel to the direction of rolling, and BW means that the longitudinal direction of the test piece is perpendicular to the direction of rolling.

[0059] As is apparent from the results in Table 11, the samples according to the present invention each have excellent properties with respect to the mechanical strength, electrical conductivity, bending property, and stress relaxation resistance. In particular, it is possible to control the stress relaxation resistance by the grain size of precipitate Y, to make the stress relaxation ratio be less than 20%. In the examples according to the present invention, by making the grain size of Y within the range from 0.02 to 0.9 µm, it was possible to attain a good stress relaxation ratio, which was a stress relaxation ratio of 13% or less, while maintaining excellent mechanical strength, electrical conductivity, and bending property. Based on the above, the alloys of the examples according to the present invention can be considered to be favorable, for example, for materials of terminals and connectors. Furthermore, although not shown in the examples, the similar effects can be exhibited when the grain size of Y is within the range from 0.01 to 2.0 µm, Contrary to the above, since the grain size of precipitate Y was too large due to a too large amount of B, the sample in Comparative example 1-1 was poor in the mechanical strength and the stress relaxation resistance. Since the grain size of precipitate Y was too small due to a too small amount of Fe, the sample in Comparative example 1-2 was poor in the stress relaxation resistance. Since the amount of P was too large, the sample in Comparative example 1-3 was poor in the stress relaxation resistance. Since the grain size of precipitate Y was too small, the sample in Comparative example 1-4 was poor in the bending property and the stress relaxation resistance. Since the grain size of precipitate Y was too small, the sample in Comparative example 1-5 was poor in the stress relaxation resistance. Since the grain size of precipitate Y was too small, the sample in Comparative example 1-6 was poor in the stress relaxation resistance.

[Table 11]

[0060] 

Table 11

	Component	Precipitate X		Precipitate Y			Number of X/ number of Y	TS	EC	Bending property		SRR
	a	Size	Density	Composition	Size	Density				GW	BW
	mass%	µm	/mm2	Compound	µm	/mm2		MPa	%IACS	R/t	R/t	%
This invention 1-1	Cr=0.2	0.03	3 x 109	Ni-Si-Cr	0.2	2 x 107	150	862	36	1.0	1.0	9
This invention 1-2	Cr=0.1	0.03	8 x 109	Ni-Si-Cr	0.3	6 x 10	0.1	855	38	1.5	1.0	10
	Zr=0.1			Ni-Si-Zr
				Ni-Si-Cr-Zr
This invention 1-3	B=0.008	0.04	1 x 1010	Ni-Si-B	0.8	2 x 109	5	833	40	1.5	1.0	12
This invention 1-4	Fe=0.15	0.08	2 x 107	Ni-Si-Fe	0.2	1 x 105	200	821	40	1.5	1.0	11
	P=0.09			Ni-Si-Fe-P
This invention 1-5	MM=0.008	0.09	7 x 107	Ni-Si-MM	0.5	3x106	25	833	39	1.5	1.0	10
This invention 1-6	T=0.2	0.05	5 x 109	Ni-Si-Ti	0.2	2 x 103	250000	882	33	1.5	1.0	7
This invention 1-7	0=0.006	0.04	3 x 109	Ni-Si-O	0.8	7 x 102	430000	832	37	1.5	1.0	11
This invention 1-8	Be=0.01	0.05	6 x 109	Ni-Si-Be	0.5	4 x 107	150	855	39	1.0	1.0	12
This invention 1-9	Cr=0.3	0.02	7 x 1010	Ni-Si-Cr	0.7	4 x 106	175	852	37	1.0	1.0	11
	Cr=0.3			Ni-Si-Hf
	Hf=0.2			Ni-Si-Cr-Hf
This invention 1-10	C=0.009	0.09	3 x 108	Ni-Si-C	0.5	3 x 103	10000	830	41	1.5	1.0	12
This invention 1-11	N=0.01	0.07	2 x 108	Ni-Si-N	0.9	5 x 105	400	820	38	1.0	1.0	12
This invention 1-12	Mn=0.2	0.08	4 x 109	Ni-Si-Mn	0.5	5 x 107	80	842	38	1.0	1.0	13
This invention 1-13		0.06	5 x 109	Ni-Si-In	0.3	2 x 108	25	845	36	1.0	1.0	12
	In=0.49			Ni-Si-Cr
	Cr=0.1			Ni-Si-In-Cr
This invention 1-14	Al=0.3	0.08	8 x 108	Ni-Si-Al	0.02	2 x 108	400	839	37	1.0	1.0	10
This invention 1-15	Co=0.2	0.04	7 x 109	Ni-Si-Co	0.7	4 x 107	175	862	39	1.0	1.0	9
Comparative example 1-1	B=1.1	1.25	2 x 108	Ni-Si-B	2.2	2 x 103	1000	789	40	2.0	1.5	22
Comparative example 1-2	Fe=0.002	0.04	3 x 107	Ni-Si-Fe	0.005	3 x 103	10000	812	43	2.0	2.0	27
Comparative example 1-3	P=1.2	0.06	6 x 109	Ni-Si-P	2.4	2 x 103	3000000	812	36	2.0	2.0	23
Comparative example 1-4	C=0.005	0.03	4 x 109	Ni-Si-C	0.007	1 x 108	40	845	39	2.5	2.0	28
Comparative example 1-5	Cr=0.5	0.04	5 x 109	Ni-Ti-Cr	0.003	5 x 109	1	854	38	2.0	2.0	35
Comparative example 1-6	Be=0.05	0.03	7 x 1010	Ni-Ti-Be	0.007	6 x 107	1200	809	37	2.0	2.0	21

(Example 7)

[0061] With respect to the copper alloys containing Ni, Si, and elements in the given amounts as shown in Table 12, with the balance being made of Cu and inevitable impurities, the test was conducted in the same manner as in Example 1. The contents of Ni and Si were as follows: 3.5 mass% of Ni and 0.8 mass% of Si in the samples of Examples according to the present invention Nos. 2-4 and 2-11; 4.0 mass% of Ni and 0.95 mass% of Si in the sample of Example according to the present invention No. 2-2; and 3.8 mass% of Ni and 0.86 mass% of Si in the samples of other Examples according to the present invention and Comparative examples. The production and measurement methods for the samples were also performed in the same manner as in Example 1. Further, the stress relaxation resistance was evaluated in the same manner as in Example 6.
As is apparent from the results in Table 12, the samples according to the present invention each have excellent properties with respect to the mechanical strength, electrical conductivity, bending property, and stress relaxation resistance. In particular, in the examples according to the present invention, by making the grain size of Y within the range from 0.05 to 0.9 µm, it was possible to attain a stress relaxation ratio of 14% or less, while maintaining excellent mechanical strength, electrical conductivity, and bending property. Based on the above, the copper alloys of the examples according to the present invention can be considered to be favorable, for example, for materials of terminals and connectors. Further, the copper alloys of the examples according to the present invention are also excellent in other properties, such as spring property. Contrary to the above, since the values of the precipitates Y were outside of the range of from 0.01 to 2.0 µm, the samples in Comparative examples each were poor in the stress relaxation ratio of 21% or more.

[Table 12]

[0062] 

Table 12

	Component		Precipitate X		Precipitate Y			Number of X/ number of Y	TS	EC	Bending property		SRR
	α	β	Size	Density	Composition	Size	Density				GW	BW
	mass%	mass%	µm	/mm2	Compound	µm	/mm2		MPa	%IACS	R/t	R/t	%
This invention 2-1	Cr=0.2	Ti=0.01	0.04	2 x 109	Ni-Cr-Ti	0.3	3 x 107	70	851	37	1.0	1.0	9
This invention 2-2	Cr=0.1	Zr=0.2	0.02	4 x 109	Ni-Cr-Zr	0.2	5 x 1010	0.1	862	39	1.5	1.0	11
This invention 2-3	B=0.01	Mn=0.02	0.05	2 x 1010	Ni-Mn-B	0.9	5 x 109	4	839	40	1.5	1.0	12
This invention 2-4	Fe=0.18	P=0.09	0.07	5 x 107	Ni-Fe-P	0.4	3 x 105	170	829	40	1.5	1.0	12
This invention 2-5	MM=0.008	0=0.006	0.10	5 x 107	Ni-MM-O	0.3	4 x 108	13	841	39	1.5	1.0	10
This invention 2-6	T=0.2	B=0.02	0.04	6 x 109	Ni-Ti-B	0.5	5 x 103	1200000	843	33	1.5	1.0	8
This invention 2-7	0=0.004	Cr=0.3	0.03	2 x 109	Ni-Cr-O	0.3	2 x 102	10000000	833	38	1.5	1.0	12
This invention 2-8	Be=0.02	Al=0.02	0.06	7 x 109	Ni-Be-Al	0.6	7 x 107	100	834	39	1.0	1.0	12
This invention 2-9	Cr-0.45	Hf=0.1	0.03	8 x 1010	Ni-Cr-Hf	0.6	7 x 108	115	857	37	1.0	1.0	11
This invention 2-10	C=0.009	Ti=0.03	0.08	2 x 108	Ni-Ti-C	0.6	3 x 103	67000	834	41	1.5	1.0	12
This invention 2-11	N=0.01	S=0.006	0.08	7 x 108	Ni-N-S	0.4	4 x 105	1750	825	39	1.0	1.0	12
This invention 2-12	Mn=0.2	Cr=0.3	0.09	8 x 109	Ni-Mn-Cr	0.6	7 x 107	115	846	40	1.0	1.0	14
This invention 2-13	In=0.2	Cr=0.5	0.09	9 x 109	Ni-In-Cr	0.2	2 x 108	45	848	36	1.0	1.0	13
This invention 2-14	Al=0.3	P=0.03	0.03	6 x 108	Ni-Al-P	0.05	3 x 108	200	846	38	1.0	1.0	10
This invention 2-15	Co=0.2	Cr=0.3	0.02	7 x 108	Ni-Co-Cr	0.30	7 x 108	100	859	38	1.0	1.0	11
Comparative example 2-1	B=1.2	Mn=0.19	2.25	6 x 108	Ni-B-Mn	4.2	6x103	100	796	40	2.0	1.5	23
Comparative example 2-2	Fe=0.002	P=0.001	0.09	6 x 107	Ni-Fe-P	0.005	5 x 103	12000	816	43	2.0	2.0	27
Comparative example 2-3	P=0.3	Fe=0.4	0.03	9 x 109	Ni-Fe-P	3.3	3 x 103	3000000	815	36	2.0	2.0	23
Comparative example 2-4	C=0.05	Ti=0.4	0.02	8 x 109	Ni-C-Ti	0.005	3 x 108	25	852	40	2.5	2.0	29
Comparative example 2-5	Cr=0.45	P=0.03	0.03	3 x 109	Ni-Cr-P	0.002	7 x 109	0.4	854	38	2.0	2.0	35
Comparative example 2-6	Zr=0.4	Fe=0.2	0.07	8 x 1010	Ni-Fe-Zr	0.009	7 x 107	1150	813	36	2.0	2.0	21

(Example 8)

[0063] With respect to the copper alloys containing Ni, Si, and elements in the given amounts as shown in Table 13, with the balance being made of Cu and inevitable impurities, the test was conducted in the same manner as in Example 1. The contents of Ni and Si were as follows: 3.5 mass% of Ni and 0.8 mass% of Si in the samples of Examples according to the present invention Nos. 3-4 and 3-11; 4.0 mass% of Ni and 0.95 mass% of Si in the samples of Examples according to the present invention Nos. 3-8 and 3-15; and 3.8 mass% of Ni and 0.86 mass% of Si in the samples of other Examples according to the present invention and Comparative examples. The production and measurement methods for the samples were also performed in the same manner as in Example 1. Further, the stress relaxation resistance was evaluated in the same manner as in Example 6.
As is apparent from the results in Table 13, the samples according to the present invention each have excellent properties with respect to the mechanical strength, electrical conductivity, bending property, and stress relaxation resistance. In particular, in the examples according to the present invention, by making the grain size of Y within the range from 0.2 to 0.6 µm, it was possible to attain a stress relaxation ratio of 15% or less, while maintaining excellent mechanical strength, bending property, and electrical conductivity. Based on the above, the copper alloys of the examples according to the present invention can be considered to be favorable, for example, for materials of terminals and connectors. Further, the copper alloys of the examples according to the present invention are also excellent in other properties, such as spring property. Contrary to the above, since the values of the precipitates Y were outside of the range of from 0.01 to 2.0 µm, the samples in Comparative examples each were poor in the stress relaxation ratio of 21% or more.

[Table 13]

[0064] 

Table 13

	Component		Precipitate X		Precipitate Y			Number of X/ number of Y	TS	EC.	Bending property		SRR
	α	β	Size	Density	Composition	Size	Density				GW	BW
	mass%	mass%	µm	/mm2	Compound	µm	/mm2		MPa	%IACS	R/t	R/t	%
This invention 3-1	Cr=0.45	Ti=0.2	0.04	5 x 109	Si-Cr-Ti	0.2	6 x 107	85	854	38	1.0	1.0	10
This invention 3-2	Cr=0.3	Zr=0.15	0.01	2x109	Si-Cr-Zr	0.3	4x1010	0.05	867	40	1.5	1.0	11
This invention 3-3	B=0.008	Mn=0.2	0.03	4 x 1010	Si-Mn-B	0.6	9 x 109	4	844	41	1.5	1.0	13
This invention 3-4	Fe=0.28	P=0.19	0.06	3x107	Si-Fe-P	0.5	4x105	75	834	41	1.5	1.0	13
This invention 3-5	MM=0.005	0=0.005	0.10	4x107	Si-MM-O	0.4	1x106	40	843	40	1.5	1.0	11
This invention 3-6	T=0.25	B=0.03	0.03	3 x 109	Si-Ti-B	0.2	9 x 103	330000	866	33	1.5	1.0	8
This invention 3-7	0=0.004	Cr=0.45	0.02	9 x 109	Si-Cr-O	0.6	8 x 102	11250000	839	39	1.5	1.0	13
This invention 3-8	Be=0.008	Al=0.012	0.02	5 x 109	Si-Be-Al	0.4	2 x 107	250	888	41	1.0.	1.0	13
This invention 3-9	Cr=0.3	Hf=0.05	0.02	6 x 1010	Si-Cr-Hf	0.5	5 x 108	120	867	37	1.0	1.0	12
This invention 3-10	C=0.01	Ti=0.06	0.07	5 x 108	Si-Ti-C	0.2	6 x 103	83000	838	43	1.5	1.0	13
This invention 3-11	N=0.007	S=0.008	0.05	9 x 108	Si-N-S	0.4	5 x 105	1800	828	39	1.0	1.0	12
This invention 3-12	Mn=0.25	Cr=0.5	0.04	8x109	Si-Mn-Cr	0.3	2x107	400	848	40	1.0	1.0	15
This invention 3-13	In=0.4	Cr=0.3	0.09	6x109	Si-In-Cr	0.2	2x108	30	853	36	1.0	1.0	13
This invention 3-14	Al=0.1	P=0.06	0.02	4x108	Si-Al-P	0.4	3x108	130	848	38	1.0	1.0	11
This invention 3-15	Co=0.2	Cr=0.15	0.03	3x1010	Si-Co-Cr	0.3	9x108	35	873	32	1.0	1.0	8
Comparative example 3-1	B=0.2	Mn=0.5	0.37	9x106	Si-B-Mn	3.2	8x103	1100	805	41	2.0	1.5	23
Comparative example 3-2	Fe=0.02	P=0.008	0.07	3x107	Si-Fe-P	0.001	3x103	10000	818	44	2.0	2.0	28
Comparative example 3-3	P=0.04	Fe=0.1	0.01	1x109	Si-Fe-P	3.3	6x103	170000	823	37	2.0	2.0	24
Comparative example 3-4	C=0.005	Ti=0.35	0.05	2x109	Si-C-Ti	0.005	1x108	20	856	41	2.5	2.0	29
Comparative example 3-5	Cr=0.25	P=0.3	0.01	3x109	Si-Cr-P	0.004	4x109	0.8	859	39	2.0	2.0	36
Comparative example 3-6	Zr=0.24	Fe=0.12	0.06	4x1010	Si-Fe-Zr	0.005	2x107	2000	821	37	2.0	2.0	21

(Example 9)

[0065] With respect to the copper alloys containing Ni, Si, and elements in the given amounts as shown in Table 14, with the balance being made of Cu and inevitable impurities, the test was conducted in the same manner as in Example 1. The contents of Ni and Si were as follows: 3.5 mass% of Ni and 0.8 mass% of Si in the samples of Examples according to the present invention Nos. 4-1 and 4-4; 4.0 mass% of Ni and 0.95 mass% of Si in the samples of Examples according to the present invention Nos. 4-2 and 4-9; and 3.8 mass% of Ni and 0.86 mass% of Si in the samples of other Examples according to the present invention and Comparative examples. The production and measurement methods for the samples were also performed in the same manner as in Example 1. Further, the stress relaxation resistance was evaluated in the same manner as in Example 6.
As is apparent from the results in Table 14, the samples according to the present invention each have excellent properties with respect to the mechanical strength, electrical conductivity, bending property, and stress relaxation resistance. In particular, in the examples according to the present invention, by making the grain size of Y within the range from 0.1 to 0.6 µm, it was possible to attain a stress relaxation ratio of 15% or less, while maintaining excellent mechanical strength, bending property, and electrical conductivity. Based on the above, the copper alloys of the examples according to the present invention can be considered to be favorable, for example, for materials of terminals and connectors. Further, the copper alloys of the examples according to the present invention are also excellent in other properties, such as spring property. Contrary to the above, since the values of the precipitates Y were outside of the range of from 0.01 to 2.0 µm, the samples in Comparative examples each were poor in the stress relaxation ratio of 21% or more.

[Table 14]

[0066] 

Table 14

	Component			Precipitate X		Precipitate Y			Number of X/ number of Y	TS	EC	Bending property		SRR
	α	β	γ	Size	Density	Composition	Size	Density				GW	BW
	mass%	mass%	mass%	µm	/mm2	Compound	µm	/mm		MPa	%IACS	R/t	R/t	%
This invention 4-1	Cr=0.5	Ti=0.1	Zr=0.2	0.02	1 x 109	Zr-Cr-Ti	0.1	1 x 107	100	822	39	1.0	1.0	10
This invention 4-2	Cr=0.25	Zr=0.1	P=0.05	0.02	5 x 109	P-Cr-Zr	0.2	5 x 1010	0.1	877	40	1.5	1.0	12
This invention 4-3	B=0.01	Mn=0.15	P=0.2	0.06	9 x 1010	P-Mn-B	0.5	2 x 109	45	846	41	1.5	1.0	13
This invention 4-4	MM= 0.005	O= 0.005	S= 0.005	0.08	5 x 107	MM-O-S	0.4	1 x 106	50	846	40	1.5	1.0	11
This invention 4-5	Ti=0.5	B-0.004	Cr=0.3	0.05	4 x 109	Cr-Ti-B	0.6	4 x 103	1000000	844	33	1.5	1.0	9
This invention 4-6	O= 0.003	Cr=0.4	Zr=0.12	0.20	3 x 109	Zr-Cr-O	0.5	3 x 102	10000000	841	39	1.5	1.0	13
This invention 4-7	Be=0.003	Al=0.01	Hf=0.2	0.05	4 x 109	Hf-Be-Al	0.1	8 x 107	50	846	41	1.0	1.0	14
This invention 4-8	Cr=0.2	Hf=0.15	Zr=0.49	0.04	8 x 1010	Zr-Cr-Hf	0.2	5 x 108	160	872	37	1.0	1.0	12
This invention 4-9	C= 0.03	Ti= 0.08	S=0.003	0.06	2 x 108	Ti-C-S	0.6	3 x 103	67000	847	43	1.5	1.0	13
This invention 4-10	N= 0.008	S= 0.008	O= 0.002	0.04	4 x 108	O-N-S	0.5	4 x105	100	838	40	1.0	1.0	13
This invention 4-11	Mn=0.5	Cr=0.1	Zr=0.3	0.01	3 x 109	Zr-Mn-Cr	0.3	3 x 107	400	852	40	1.0	1.0	15
This invention 4-12	In=0.3	Cr=0.3	Zr=0.3	0.03	8 x 109	Zr-In-Cr	0.4	4 x 108	20	862	38	1.0	1.0	13
This invention 4-13	Al= 0.25	P=0.08	Ti= 0.49	0.04	8 x 108	Ti-Al-P	0.4	8 x 108	100	849	39	1.0	1.0	12
This invention 4-14	Co=0.1	Cr=0.2	Zr=0.3	0.03	3 x 1010	Co-Mn-Cr	0.3	1 x 108	300	852	40	1.0	1.0	15
Comparative example 4-1	B= 0.0002	Mn=0.5	P=0.6	0.55	4 x 106	Mn-B-P	3.6	3 x 103	130	807	42	2.0	1.5	24
Comparative example 4-2	C= 0.008	T=0.2	Cr=0.2	0.01	8 x 109	Cr-C-Ti	0.009	2 x 108	40	860	41	2.5	2.0	30
Comparative example 4-3	Cr= 0.25	P=0.3	Al=0.2	0.04	9 x 109	Al-Cr-P	0.006	8 x 109	1.1	860	39	2.0	2.0	37
Comparative example 4-4	Zr= 0.24	Fe= 0.12	S= 0.003	0.02	5 x 1010	Fe-Zr-S	0.004	5 x 107	1000	829	38	2.0	2.0	22

INDUSTRIAL APPLICABILITY

[0067] The copper alloy of the present invention can be preferably applied, for example, to lead frame, connector, or terminal materials for electric and electronic instrument materials, e.g. connector/terminal materials, relays, and switches for electric and electronic instruments, such as on-vehicle/automobile electric and electronic instruments.
Having described our invention as related to the present embodiments, it is our intention that the present invention not be limited by any of the details of the description, unless otherwise specified, but rather be construed broadly as set out in the accompanying claims.

Claims

1. A copper alloy, having: a precipitate Y composed of Ni and/or Si, and at least one or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be; and a precipitate X composed of Ni and Si, wherein a grain diameter of the precipitate Y is 0.01 to 2 µm, and wherein the number of precipitates X per mm² is 20 to 2,000 times the number of precipitates Y per mm².

2. The copper alloy according to Claim 1, wherein the grain diameter of the precipitate Y is 0.02 to 0.9 µm.

3. The copper alloy according to Claim 1, having: a precipitate X composed of Ni and Si; and at least one precipitate selected from the group consisting of a precipitate Y1 composed of Ni, Si, and Cr, a precipitate Y2 composed of Ni, Si, and Co, a precipitate Y3 composed of Ni, Si, and Zr, and a precipitate Z composed of Ni, Si, and B, wherein a grain diameter of the at least one precipitate selected from the group consisting of the precipitates Y1, Y2, Y3, and Z is 0.1 to 2 µm.

4. The copper alloy according to Claim 1, comprising: Ni 2.0 to 5.0 mass%, Si 0.3 to 1.5 mass%, at least one or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be each in an amount of 0.005 to 1.0 mass%, with a balance being Cu and inevitable impurities; said copper alloy having a precipitate X composed of Ni and Si; and a precipitate Y composed of Ni, Si, and at least one or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be, wherein a grain diameter of the precipitate Y is 0.01 to 2 µm.

5. The copper alloy according to Claim 1, comprising: Ni 2.0 to 5.0 mass%, Si 0.3 to 1.5 mass%, at least one or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Pe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be each in an amount of 0.005 to 1.0 mass%, with a balance being Cu and inevitable impurities; said copper alloy having a precipitate X composed of Ni and Si; and a precipitate Y composed of Ni, and at least two or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be, wherein a grain diameter of the precipitate Y is 0.01 to 2 µm.

6. The copper alloy according to Claim 1, comprising: Ni 2.0 to 5.0 mass%, Si 0.3 to 1.5 mass%, at least one or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be each in an amount of 0.005 to 1.0 mass%, with a balance being Cu and inevitable impurities; said copper alloy having a precipitate X composed of Ni and Si; and a precipitate Y composed of Si, and at least two or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be, wherein a grain diameter of the precipitate Y is 0.01 to 2 µm.

7. The copper alloy according to Claim 1, comprising: Ni 2.0 to 5.0 mass%, Si 0.3 to 1.5 mass%, at least one or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be each in an amount of 0.005 to 1.0 mass%, with a balance being Cu and inevitable impurities; said copper alloy having a precipitate X composed of Ni and Si; and a precipitate Y composed of at least three or more selected from the group consisting of B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Misch metal (MM), Co, and Be, wherein a grain diameter of the precipitate Y is 0.01 to 2 µm.

8. The copper alloy according to any one of Claims 1 to 7, wherein the melting point of the precipitate Y is higher than a solid solution treatment temperature.

9. The copper alloy according to any one of Claims 1 to 8, wherein the number of precipitates X is 10⁸ to loll per mm², and the number of precipitates Y is 10⁴ to 10⁸ per mm².

10. The copper alloy according to any one of Claims 1 to 9, wherein a composition of the copper alloy further comprises at least one or more selected from Sn 0.1 to 1.0 mass%, Zn 0.1 to 1,0 mass%, and Mg 0.05 to 0.5 mass%.

11. The copper alloy according to any one of Claims 1 to 10, which has a stress relaxation ratio of less than 20%.

12. The copper alloy according to any one of Claims 1 to 11, which is for use as a material of an electric or electronic instrument.

13. A production method for producing a copper alloy as claimed in any one of Claims 1 to 12, comprising the steps of:

melting a copper alloy having the element composition described in any one of Claims 4 to 7 and 10;

casting into an ingot; and

hot-rolling the ingot.

14. The production method according to claim 13, which comprises the additional steps of:

heating the ingot at a temperature rising rate of 20 to 200°C/hr, after the step of casting the ingot;

holding the resultant ingot at 850 to 1050°C for 0.5 to 5 hours ;

the said hot-rolling, to finish the hot-rolling at a finishing temperature of 300 to 700°C; and

quenching the hot-rolled product.

15. The production method according to Claim 13 or 14, wherein, after the hot-rolling step, the resultant alloy is formed into a given thickness, through a combination of solution treatment, annealing, and cold-rolling, and
wherein the solution treatment temperature is 600 to 820°C for an Ni amount of 2.0 mass% or more but less than 2.5 mass%, 700 to 870°C for an Ni amount of 2.5 mass% or more but less than 3-0 mass%, 750 to 920°C for an Ni amount of 3.0 mass% or more but less than 3.5 mass%, 800 to 970°C for an Ni amount of 3.5 mass% or more but less than 4.0 mass%, 850 to 1020°C for an Ni amount of 4.0 mass% or more but less than 4.5 mass%, and 920 to 1050°C for an Ni amount of 4.5 mass% or more but less than 5.0 mass%.

Ansprüche

1. Kupferlegierung, die aufweist: ein Ausscheidungsprodukt Y, das aus Ni und/oder Si, und mindestens einem oder mehreren besteht, die aus der Gruppe ausgewählt werden, die aus B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmetall (MM), Co, und Be besteht; und ein Ausscheidungsprodukt X, das aus Ni und Si besteht, wobei ein Korndurchmesser des Ausscheidungsproduktes Y 0,01 bis 2 µm beträgt, und wobei die Anzahl an Ausscheidungsprodukten X pro mm² 20- bis 2000-mal die Anzahl an Ausscheidungsprodukten Y pro mm² beträgt.

2. Kupferlegierung nach Anspruch 1, wobei der Korndurchmesser des Ausscheidungsproduktes Y 0,02 bis 0,9 µm beträgt.

3. Kupferlegierung nach Anspruch 1, die aufweist: ein Ausscheidungsprodukt X, das aus Ni und Si besteht; und mindestens ein Ausscheidungsprodukt, das aus der Gruppe ausgewählt wird, die aus einem Ausscheidungsprodukt Y1, das aus Ni, Si, und Cr besteht, einem Ausscheidungsprodukt Y2, das aus Ni, Si, und Co besteht, einem Ausscheidungsprodukt Y3, das aus Ni, Si, und Zr besteht, und einem Ausscheidungsprodukt Z, das aus Ni, Si, und B besteht, besteht, wobei ein Korndurchmesser von dem mindestens einem Ausscheidungsprodukt, das aus der Gruppe ausgewählt wird, die aus Y1, Y2, Y3, und Z besteht, 0,1 bis 2 µm beträgt.

4. Kupferlegierung nach Anspruch 1, umfassend: Ni 2,0 bis 5,0 Massen-%, Si 0,3 bis 1,5 Massen-%, mindestens eines oder mehrere, die aus der Gruppe ausgewählt werden, die aus B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmetall (MM), Co, und Be besteht, jeweils in einer Menge von 0,005 bis 1,0 Massen-%, wobei ein Ausgleich Cu und unvermeidbare Verunreinigungen ist; wobei die Kupferlegierung ein Ausscheidungsprodukt X aufweist, das aus Ni und Si besteht; und ein Ausscheidungsprodukt Y, das aus Ni, Si, und mindestens einem oder mehreren besteht, die aus der Gruppe ausgewählt werden, die aus B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmetall (MM), Co, und Be besteht, wobei ein Korndurchmesser des Ausscheidungsproduktes Y 0,01 bis 2 µm beträgt.

5. Kupferlegierung nach Anspruch 1, umfassend: Ni 2,0 bis 5,0 Massen-%, Si 0,3 bis 1,5 Massen-%, mindestens eines oder mehrere, die aus der Gruppe ausgewählt werden, die aus B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmetall (MM), Co, und Be besteht, jeweils in einer Menge von 0,005 bis 1,0 Massen-%, wobei ein Ausgleich Cu und unvermeidbare Verunreinigungen ist; wobei die Kupferlegierung ein Ausscheidungsprodukt X aufweist, das aus Ni und Si besteht; und ein Ausscheidungsprodukt Y, das aus Ni, und mindestens zwei oder mehreren besteht, die aus der Gruppe ausgewählt werden, die aus B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmetall (MM), Co, und Be besteht, wobei ein Korndurchmesser des Ausscheidungsproduktes Y 0,01 bis 2 µm beträgt.

6. Kupferlegierung nach Anspruch 1, umfassend: Ni 2,0 bis 5,0 Massen-%, Si 0,3 bis 1,5 Massen-%, mindestens eines oder mehrere, die aus der Gruppe ausgewählt werden, die aus B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmetall (MM), Co, und Be besteht, jeweils in einer Menge von 0,005 bis 1,0 Massen-%, wobei ein Ausgleich Cu und unvermeidbare Verunreinigungen ist; wobei die Kupferlegierung ein Ausscheidungsprodukt X aufweist, das aus Ni und Si besteht; und ein Ausscheidungsprodukt Y, das aus Si, und mindestens zwei oder mehreren besteht, die aus der Gruppe ausgewählt werden, die aus B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmetall (MM), Co, und Be besteht, wobei ein Korndurchmesser des Ausscheidungsproduktes Y 0,01 bis 2 µm beträgt.

7. Kupferlegierung nach Anspruch 1, umfassend: Ni 2,0 bis 5,0 Massen-%, Si 0,3 bis 1,5 Massen-%, mindestens eines oder mehrere, die aus der Gruppe ausgewählt werden, die aus B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmetall (MM), Co, und Be besteht, jeweils in einer Menge von 0,005 bis 1,0 Massen-%, wobei ein Ausgleich Cu und unvermeidbare Verunreinigungen ist; wobei die Kupferlegierung ein Ausscheidungsprodukt X aufweist, das aus Ni und Si besteht; und ein Ausscheidungsprodukt Y, das aus mindestens drei oder mehreren besteht, die aus der Gruppe ausgewählt werden, die aus B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmetall (MM), Co, und Be besteht, wobei ein Korndurchmesser des Ausscheidungsproduktes Y 0,01 bis 2 µm beträgt.

8. Kupferlegierung nach einem der Ansprüche 1 bis 7, wobei der Schmelzpunkt des Ausscheidungsproduktes Y höher als eine Temperatur einer Mischkristallbehandlung (solid solution treatment) ist.

9. Kupferlegierung nach einem der Ansprüche 1 bis 8, wobei die Anzahl der Ausscheidungsprodukte X 10⁸ bis 10¹² pro mm² beträgt, und die Anzahl der Ausscheidungsprodukte Y 10⁴ bis 10⁸ pro mm² beträgt.

10. Kupferlegierung nach einem der Ansprüche 1 bis 9, wobei eine Zusammensetzung der Kupferlegierung weiter mindestens eines oder mehrere umfasst, die aus Sn 0,1 bis 1,0 Massen-%, Zn 0,1 bis 1,0 Massen-%, und Mg 0,05 bis 0,5 Massen-% ausgewählt werden.

11. Kupferlegierung nach einem der Ansprüche 1 bis 10, welche ein Spannungs-Relaxations-Verhältnis von weniger als 20% aufweist.

12. Kupferlegierung nach einem der Ansprüche 1 bis 11, welche zur Verwendung als ein Material eines elektrischen oder elektronischen Instrumentes bestimmt ist.

13. Herstellungsverfahren zum Herstellen einer Kupferlegierung, wie sie in einem der Ansprüche 1 bis 12 beansprucht wird, das die folgenden Schritte umfasst:

Schmelzen einer Kupferlegierung, die eine Elementzusammensetzung aufweist, die in einem der Ansprüche 4 bis 7 und 10 beschrieben wird;

Gießen eines Rohblockes; und

Heiß-Walzen des Rohblockes.

14. Herstellungsverfahren nach Anspruch 13, welches die folgenden zusätzlichen Schritte umfasst:

Heizen des Rohblockes mit einer Geschwindigkeit des Temperaturanstiegs von 20 bis 200°C/hr, nach dem Schritt des Gießens des Rohblockes;

Halten des resultierenden Rohblockes bei 850 bis 1050°C für 0,5 bis 5 Stunden;

das Heiß-Walzen, um das Heiß-Walzen bei einer Endtemperatur von 300 bis 700°C zu beenden; und

Abschrecken des heiß gewalzten Produktes.

15. Herstellungsverfahren nach Anspruch 13 oder 14, wobei, nach dem Heiß-Walz-Schritt, die resultierende Legierung in eine vorgegebene Dicke geformt wird, durch eine Kombination aus Lösungsbehandlung, Ausglühen, und Kalt-Walzen, und
wobei die Temperatur der Lösungsbehandlung 600 bis 820°C für eine Ni-Menge von 2,0 Massen-% oder mehr, aber weniger als 2,5 Massen-%, 700 bis 870°C für eine Ni-Menge von 2,5 Massen-% oder mehr, aber weniger als 3,0 Massen-%, 750 bis 920°C für eine Ni-Menge von 3,0 Massen-% oder mehr, aber weniger als 3,5 Massen-%, 800 bis 970°C für eine Ni-Menge von 3,5 Massen-% oder mehr, aber weniger als 4,0 Massen-%, 850 bis 1020°C für eine Ni-Menge von 4,0 Massen-% oder mehr, aber weniger als 4,5 Massen-%, und 920 bis 1050°C für eine Ni-Menge von 4,5 Massen-% oder mehr, aber weniger als 5,0 Massen-% beträgt.

Revendications

1. Alliage de cuivre, ayant : un précipité Y composé de Ni et/ou de Si, et d'au moins un ou plusieurs éléments choisis dans le groupe constitué de B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmétal (MM), Co, et Be ; et un précipité X composé de Ni et de Si, dans lequel un diamètre de grain du précipité Y est de 0,01 à 2 µm, et dans lequel le nombre de précipités X par mm² est de 20 à 2.000 fois le nombre de précipités Y par mm².

2. Alliage de cuivre selon la revendication 1, dans lequel le diamètre de grain du précipité Y est de 0,02 à 0,9 µm.

3. Alliage de cuivre selon la revendication 1, ayant : un précipité X composé de Ni et de Si ; et au moins un précipité choisi dans le groupe constitué d'un précipité Y1 composé de Ni, Si et Cr, d'un précipité Y2 composé de Ni, Si, et Co, d'un précipité Y3 composé de Ni, Si, et Zr, et d'un précipité Z composé de Ni, Si, et B, dans lequel un diamètre de grain de l'au moins un précipité choisi dans le groupe constitué des précipités Y1, Y2, Y3, et Z est de 0,1 à 2 µm.

4. Alliage de cuivre selon la revendication 1, comprenant: du Ni de 2,0 à 5,0 % en masse, du Si de 0,3 à 1,5 % en masse, au moins un élément ou plus choisi(s) dans le groupe constitué de B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmétal (MM), Co, et Be chacun en une quantité de 0,005 à 1,0 % en masse, avec le reste étant du Cu et des impuretés inévitables ; ledit alliage de cuivre ayant un précipité X composé de Ni et de Si ; et un précipité Y composé de Ni, Si, et d'au moins un élément ou plus choisi(s) dans le groupe constitué de B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, ,N, Mischmétal (MM), Co, et Be, dans lequel un diamètre de grain du précipité Y est de 0,01 à 2 µm.

5. Alliage de cuivre selon la revendication 1, comprenant: du Ni de 2,0 à 5,0 % en masse, du Si de 0,3 à 1,5 % en masse, au moins un élément ou plus choisi(s) dans le groupe constitué de B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmétal (MM), Co, et Be chacun en une quantité de 0,005 à 1,0 % en masse, avec le reste étant du Cu et des impuretés inévitables; ledit alliage de cuivre ayant un précipité X composé de Ni et de Si; et un précipité Y composé de Ni, et d'au moins deux ou plusieurs éléments choisis dans le groupe constitué de B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmétal (MM), Co, et Be, dans lequel un diamètre de grain du précipité Y est de 0,01 à 2 µm.

6. Alliage de cuivre selon la revendication 1, comprenant: du Ni de 2,0 à 5,0 % en masse, du Si de 0,3 à 1,5 % en masse, au moins un élément ou plus choisi(s) dans le groupe constitué de B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmétal (MM), Co, et Be chacun en une quantité de 0,005 à 1,0 % en masse, avec le reste étant du Cu et des impuretés inévitables; ledit alliage de cuivre ayant un précipité X composé de Ni et de Si; et un précipité Y composé de Si, et d'au moins deux éléments ou plus choisis dans le groupe constitué de B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmétal (MM), Co, et Be, dans lequel un diamètre de grain du précipité Y est de 0,01 à 2 µm.

7. Alliage de cuivre selon la revendication 1, comprenant: du Ni de 2,0 à 5,0 % en masse, du Si de 0,3 à 1,5 % en masse, au moins un élément ou plus choisi(s) dans le groupe constitué de B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmétal (MM), Co, et Be chacun en une quantité de 0,005 à 1,0 % en masse, avec le reste étant du Cu et des impuretés inévitables; ledit alliage de cuivre ayant un précipité X composé de Ni et de Si; et un précipité Y composé d'au moins trois éléments ou plus choisis dans le groupe constitué de B, Al, As, Hf, Zr, Cr, Ti, C, Fe, P, In, Sb, Mn, Ta, V, S, O, N, Mischmétal (MM), Co, et Be, dans lequel un diamètre de grain du précipité Y est de 0,01 à 2 µm.

8. Alliage de cuivre selon l'une quelconque des revendications 1 à 7, dans lequel le point de fusion du précipité Y est supérieur à une température de traitement de mise en solution solide.

9. Alliage de cuivre selon l'une quelconque des revendications 1 à 8, dans lequel le nombre de précipités X est de 10⁸ à 10¹² par mm², et le nombre de précipités Y est de 10⁴ à 10⁸ par mm².

10. Alliage de cuivre selon l'une quelconque des revendications 1 à 9, dans lequel une composition de l'alliage de cuivre comprend en outre au moins un élément ou plus choisi(s) parmi le Sn de 0,1 à 1,0 % en masse, le Zn de 0,1 à 1,0 % en masse, et le Mg de 0,05 à 0,5 % en masse.

11. Alliage de cuivre selon l'une quelconque des revendications 1 à 10, qui possède un rapport de relaxation de contrainte inférieur à 20 %.

12. Alliage de cuivre selon l'une quelconque des revendications 1 à 11, qui est destiné à l'utilisation en tant que matériau d'un instrument électrique ou électronique.

13. Procédé de production destiné à produire un alliage de cuivre tel que revendiqué dans l'une quelconque des revendications 1 à 12, comprenant les étapes qui consistent à:

faire fondre un alliage de cuivre ayant la composition en éléments décrite dans l'une quelconque des revendications 4 à 7 et 10;

le faire couler en lingot; et

effectuer un laminage à chaud du lingot.

14. Procédé de production selon la revendication 13, qui comprend les étapes supplémentaires consistant à:

chauffer le lingot à un taux d'élévation de température de 20 à 200°C/h, après l'étape consistant à faire couler le lingot;

maintenir le lingot ainsi obtenu à une température de 850 à 1050°C pendant 0,5 à 5 heure(s);

effectuer ledit laminage à chaud, jusqu'à la fin du laminage à chaud à une température finale de 300 à 700°C; et

tremper le produit laminé à chaud.

15. Procédé de production selon la revendication 13 ou 14, dans lequel, après l'étape consistant au laminage à chaud, l'alliage ainsi obtenu est formé de façon à avoir une épaisseur donnée, à travers une combinaison de traitement de mise en solution, de recuit et de laminage à froid, et
dans lequel la température du traitement de mise en solution est de 600 à 820°C pour une quantité de Ni de 2,0 % en masse ou plus mais inférieure à 2,5 % en masse, de 700 à 870°C pour une quantité de Ni de 2,5 % en masse ou plus mais inférieure à 3,0 % en masse, de 750 à 920°C pour une quantité de Ni de 3,0 % en masse ou plus mais inférieure à 3,5 % en masse, de 800 à 970°C pour une quantité de Ni de 3,5 % en masse ou plus mais inférieure à 4,0 % en masse, de 850 à 1020°C pour une quantité de Ni de 4,0 % en masse ou plus mais inférieure à 4,5 % en masse, et de 920 à 1050°C pour une quantité de Ni de 4,5 % en masse ou plus mais inférieure à 5,0 % en masse.