CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to and benefits of Chinese Patent Application Serial
No.
201710453134.2, filed on June 15, 2017. The entire content of the above-referenced application is incorporated herein by
reference.
FIELD
[0002] This application relates to the field of materials technologies, and specifically,
to a magnesium alloy with high thermal conductivity and application thereof, and more
specifically, to a magnesium alloy with high thermal conductivity, an inverter housing
of which at least a part is formed by the magnesium alloy with high thermal conductivity,
an inverter including the inverter housing, and a vehicle including the inverter.
BACKGROUND
[0003] A conventional die casting magnesium alloy on the current market is AZ91D, including
main components as follows: Al: 8.5∼9.5%, Zn: 0.45∼0.90%, Mn: 0.17∼0.4%, Si: ≤0.05%,
Cu: 0.025%, Ni: ≤0.001%, Fe: ≤0.004%, and magnesium. This material has good fluidity
and formability, low costs, and relatively high mechanical properties. However, the
thermal conductivity of this material is relatively low, which is less than 60 W/m·K,
thereby limiting broad application of magnesium alloys.
[0004] Therefore, current research on magnesium alloys remains to be improved.
SUMMARY
[0005] This application is directed to solve one of the technical problems in the related
technology at least to some extent. To this end, an objective of this application
is to provide a die casting magnesium alloy having good thermal conductivity or having
ideal mechanical properties as well.
[0006] According to an aspect of this application, this application provides a magnesium
alloy with high thermal conductivity. According to embodiments of this application,
based on the total mass of the magnesium alloy with high thermal conductivity, the
magnesium alloy with high thermal conductivity includes: 2.0-4.0 wt% of Al, 0.1-0.3
wt% of Mn, 1.0-2.0 wt% of La, 2.0-4.0 wt% of Ce, 0.1-1.0 wt% of Nd, 0.5-2.0 wt% of
Zn, 0.1-0.5 wt% of Ca, less than 0.1 wt% of Sr, less than 0.1 wt% of Cu, and magnesium.
It is found that the magnesium alloy including the foregoing components has extremely
high thermal conductivity and ideal mechanical properties at the same time, and can
be effectively applied to conditions and environments that require high thermal conductivity
and a light weight, for example, being used to manufacture an inverter housing of
a vehicle, thereby greatly expanding the application scope of magnesium alloys.
[0007] According to another aspect of this application, this application provides an inverter
housing. According to an embodiment of this application, at least a part of the inverter
housing is formed by the foregoing magnesium alloy with high thermal conductivity.
In this way, the inverter housing has extremely high thermal conductivity and good
heat-dissipation performance, so that the safety and service life of an inverter using
the inverter housing are improved significantly.
[0008] According to still another aspect of this application, this application provides
an inverter. According to an embodiment of this application, the inverter includes
the foregoing inverter housing. It is found that the inverter has good heat-dissipation
performance, so that the safety is greatly improved and the service life is significantly
increased.
[0009] According to yet another aspect of this application, this application provides a
vehicle. According to an embodiment of this application, the vehicle includes the
foregoing inverter. The vehicle has all the foregoing features and advantages of the
inverter, which are not described herein again.
DETAILED DESCRIPTION
[0010] The following describes embodiments of this application in detail. The embodiments
described below are exemplary and are only used to interpret this application, instead
of limiting this application. Technologies or conditions that are not explicitly specified
in the embodiments are technologies or conditions described in documents in the art
or as described in product specifications. All agents and instruments used in the
embodiments whose manufacturers are not explicitly specified are conventional products
available on the market.
[0011] According to an aspect of this application, this application provides a magnesium
alloy with high thermal conductivity. According to the embodiments of this application,
based on the total mass of the magnesium alloy with high thermal conductivity, the
magnesium alloy with high thermal conductivity includes: 2.0-4.0 wt% of Al, 0.1-0.3
wt% of Mn, 1.0-2.0 wt% of La, 2.0-4.0 wt% of Ce, 0.1-1.0 wt% of Nd, 0.5-2.0 wt% of
Zn, 0.1-0.5 wt% of Ca, less than 0.1 wt% of Sr, less than 0.1 wt% of Cu, and magnesium.
It is found that the magnesium alloy including the foregoing components has extremely
high thermal conductivity and ideal mechanical performance at the same time, and can
be effectively applied to conditions and scenarios that require high thermal conductivity
and a light weight, for example, being used to manufacture an inverter housing of
a vehicle, thereby greatly expanding the application scope of magnesium alloys.
[0012] According to the embodiments of this application, in the foregoing magnesium alloy:
aluminum can improve the strength and anti-corrosion performance of the magnesium
alloy and manganese can improve the elongation and toughness of the magnesium alloy.
Adding rare earth elements such as La, Ce and Nd can obviously enhance the high-temperature
performance of the magnesium alloy and refine particles of the magnesium alloy during
the casting process. In addition, magnesium can form a solid solution with the foregoing
rare earth elements, a zone rich in magnesium is a simple eutectic zone with a low
melting point, and magnesium is distributed in the shape of a net at the grain boundary
to prohibit the formation of micro pores, thereby improving the casting performance
and thermal conductivity of the magnesium alloy. Nd has relatively large impact on
fine-grain strengthening of the magnesium alloy. The refining effect of Ce on micro
structures helps to improve the mechanical properties and anti-corrosion performance
of the magnesium alloy. Zinc can achieve solution strengthening and form a strengthening
phase. Both a small amount of Ca and a small amount of Sr can prevent the magnesium
alloy from oxidation during the process of smelting. These components are mixed according
to the foregoing proportions to form the magnesium alloy. Due to the synergistic effect
of these components, the obtained magnesium alloy has high thermal conductivity and
mechanical properties at the same time, and can be effectively applied to multiple
fields, especially to scenarios that require relatively high thermal conductivity.
[0013] According to the embodiments of this application, to further improve usage performance
of the magnesium alloy, based on the total mass of the magnesium alloy with high thermal
conductivity, the magnesium alloy may include: 0.15-0.3 wt% of Mn and 2.5-4.0 wt%
of Ce. In this way, it is ensured that the magnesium alloy has ideal thermal conductivity
and high mechanical properties at the same time, to better satisfy usage requirements
of different operating environments and conditions.
[0014] According to a specific embodiment of this application, based on the total mass of
the magnesium alloy with high thermal conductivity, the magnesium alloy may include:
3.0 wt% of Al, 0.25 wt% of Mn, 1.55 wt% of La, 3.0 wt% of Ce, 0.13 wt% of Nd, 0.6
wt% of Zn, 0.15 wt% of Ca, less than 0.1 wt% of Sr, less than 0.1 wt% of Cu, and magnesium.
[0015] According to another specific embodiment of this application, based on the total
mass of the magnesium alloy with high thermal conductivity, the magnesium alloy may
include: 2.0 wt% of Al, 0.15 wt% of Mn, 2.0 wt% of La, 2.5 wt% of Ce, 0.1 wt% of Nd,
2.0 wt% of Zn, 0.1 wt% of Ca, less than 0.1 wt% of Sr, less than 0.1 wt% of Cu, and
magnesium.
[0016] According to another specific embodiment of this application, based on the total
mass of the magnesium alloy with high thermal conductivity, the magnesium alloy may
include: 4.0 wt% of Al, 0.1 wt% of Mn, 1.0 wt% of La, 2.0 wt% of Ce, 1.0 wt% of Nd,
0.5 wt% of Zn, 0.5 wt% of Ca, less than 0.1 wt% of Sr, less than 0.1 wt% of Cu, and
magnesium.
[0017] According to another specific embodiment of this application, based on the total
mass of the magnesium alloy with high thermal conductivity, the magnesium alloy may
include: 2.5 wt% of Al, 0.3 wt% of Mn, 1.0 wt% of La, 4.0 wt% of Ce, 0.5 wt% of Nd,
1.5 wt% of Zn, 0.3 wt% of Ca, less than 0.1 wt% of Sr, less than 0.1 wt% of Cu, and
magnesium.
[0018] It is found that the magnesium alloy including the foregoing components has high
thermal conductivity and ideal mechanical properties at the same time.
[0019] Through a large number of experiments, it is verified that the magnesium alloy according
to the embodiments of this application has thermal conductivity obviously higher than
that of an existing magnesium alloy. Experimental results show that the thermal conductivity
of the magnesium alloy including the foregoing components with the corresponding proportions
may be greater than 110 w/m·K. In this way, the magnesium alloy can be effectively
applied to scenarios that require relatively high thermal conductivity. In addition,
the magnesium alloy has advantages such as a low density, a high specific strength,
a high specific modulus, a high property of tremble elimination, and high resistance
to corrosion caused by organic matter and alkali.
[0020] In addition, the magnesium alloy according to the embodiments of this application
may further satisfy at least one of the following conditions: a tensile strength is
greater than 220 MPa; a yield strength is greater than 150 MPa; and an elongation
is greater than 4%. Specifically, the magnesium alloy may satisfy only one of the
foregoing conditions. For example, the magnesium alloy may only satisfy the condition
that the tensile strength is greater than 220 MPa, or may only satisfy the condition
that the yield strength is greater than 150 MPa, or may only satisfy the condition
that the elongation is greater than 4%. Alternatively, the magnesium alloy may satisfy
two of the foregoing conditions. For example, the magnesium alloy may satisfy the
condition that the tensile strength is greater than 220 MPa and the condition that
the yield strength is greater than 150 MPa, or may satisfy the condition that the
tensile strength is greater than 220 MPa and the condition that the elongation is
greater than 4%, or may satisfy the condition that the yield strength is greater than
150 MPa and the condition that the elongation is greater than 4%. Alternatively, the
magnesium alloy may also satisfy the three conditions that the tensile strength is
greater than 220 MPa, the yield strength is greater than 150 MPa and the elongation
is greater than 4%. In this way, it is ensured that the magnesium alloy has ideal
thermal conductivity and better mechanical properties at the same time, and can satisfy
usage requirements in different fields as well as different operating environments
and conditions.
[0021] According to another aspect of this application, this application provides an inverter
housing. According to an embodiment of this application, at least a part of the inverter
housing is formed by the foregoing magnesium alloy with high thermal conductivity.
In this way, the inverter housing has extremely high thermal conductivity and high
heat-dissipation performance, so that the safety and service life of an inverter using
the inverter housing are improved significantly.
[0022] According to the embodiments of this application, the specific structure of the inverter
housing is not particularly limited and may be any existing structure of an inverter
housing in the field. A person skilled in the art may choose flexibly according to
an actual demand. Moreover, a part of the inverter housing, such as a part that requires
higher thermal conductivity, may be prepared by using the magnesium alloy in this
application. Alternatively, the entire inverter housing may be prepared by using the
magnesium alloy in this application. A person skilled in the art may also choose flexibly
according to costs and usage requirements.
[0023] According to another aspect of this application, this application provides an inverter.
According to an embodiment of this application, the inverter includes the foregoing
inverter housing. It is found that the inverter has good heat-dissipation performance,
so that the safety is greatly improved and the service life is significantly increased.
Moreover, a person skilled in the art may understand that the inverter has all the
features and advantages of the foregoing inverter housing, which are not described
herein again.
[0024] According to the embodiments of this application, apart from the inverter housing,
the inverter further includes necessary structures and parts of a conventional inverter,
such as an inverter bridge, control logic and a filter circuit, which are not described
in further detail herein.
[0025] According to another aspect of this application, this application provides a vehicle.
According to an embodiment of this application, the vehicle includes the foregoing
inverter. In this way, the inverter of the vehicle has good thermal conductivity and
mechanical properties, thereby greatly improving the safety. In addition, the inverter
housing is prepared by using a magnesium alloy, which helps to reduce the weight of
the vehicle and improve user experience. The vehicle has all the features and advantages
of the foregoing inverter, which are not described herein again.
[0026] According to the embodiments of this application, apart from the inverter, the vehicle
has necessary structures and parts of a conventional vehicle, such as a body, an engine,
wheels and interior decoration items, which are not described in further detail herein.
Embodiment 1
[0027] Components of the magnesium alloy: 3.0 wt% of Al, 0.25 wt% of Mn, 1.55 wt% of La,
3.0 wt% of Ce, 0.13 wt% of Nd, 0.6 wt% of Zn, 0.15 wt% of Ca, less than 0.1 wt% of
Sr, less than 0.1 wt% of Cu, and magnesium.
[0028] Preparation procedure: put a pure magnesium ingot and a pure aluminum ingot into
a smelting furnace, where the smelting temperature is 700-750°C; add an Mg-Ca master
alloy, an Mg-Mn master alloy and an Mg-Zn master alloy into the smelting furnace and
completely melt down the master alloys, where the smelting temperature is 700-750°C;
add an Mg-La master alloy, an Mg-Ce master alloy and an Mg-Nd master alloy into the
smelting furnace, where the smelting temperature is 700-750°C, and at the same time
add a covering agent onto the surface of the melt; perform a 15-minute refining treatment
on the melt using an RJ-5 flux, where the refining temperature is 730-760°C, and then
let the melt stand for 80-120 minutes, where the temperature is 650-730°C. Sr and
Cu may be introduced using impurities of the foregoing raw materials, and therefore,
it is unnecessary to add Sr and Cu separately.
Embodiment 2
[0029] Components of the magnesium alloy: 2.0 wt% of Al, 0.15 wt% of Mn, 2.0 wt% of La,
2.5 wt% of Ce, 0.1 wt% of Nd, 2.0 wt% of Zn, 0.1 wt% of Ca, less than 0.1 wt% of Sr,
less than 0.1 wt% of Cu, and magnesium.
[0030] Preparation procedure: same as the preparation procedure in Embodiment 1.
Embodiment 3
[0031] Components of the magnesium alloy: 4.0 wt% of Al, 0.1 wt% of Mn, 1.0 wt% of La, 2.0
wt% of Ce, 1.0 wt% of Nd, 0.5 wt% of Zn, 0.5 wt% of Ca, less than 0.1 wt% of Sr, less
than 0.1 wt% of Cu, and magnesium.
[0032] Preparation procedure: same as the preparation procedure in Embodiment 1.
Embodiment 4
[0033] Components of the magnesium alloy: 2.5 wt% of Al, 0.3 wt% of Mn, 1.0 wt% of La, 4.0
wt% of Ce, 0.5 wt% of Nd, 0.5 wt% of Zn, 0.3 wt% of Ca, less than 0.1 wt% of Sr, less
than 0.1 wt% of Cu, and magnesium.
[0034] Preparation procedure: same as the preparation procedure in Embodiment 1.
Comparative Example 1
[0035] Components of the magnesium alloy: 6 wt% of Al, 0.4 wt% of Mn, 0.48 wt% of Zn, 1.2
wt% of Ca, less than 0.1 wt% of Sr, less than 0.1 wt% of Cu, and magnesium.
[0036] Preparation procedure: same as the preparation procedure in Embodiment 1.
Comparative Example 2
[0037] Components of the magnesium alloy: 6.0 wt% of Al, 0.25 wt% of Mn, 1.55 wt% of La,
3.0 wt% of Ce, 0.013 wt% of Nd, 0.6 wt% of Zn, 0.15 wt% of Ca, less than 0.1 wt% of
Sr, less than 0.1 wt% of Cu, and magnesium.
[0038] Preparation procedure: same as the preparation procedure in Embodiment 1.
Embodiment 5
[0039] Mechanical properties and the coefficient of thermal conductivity of magnesium alloys
prepared in Embodiments 1 to 4 and Comparative Examples 1 and 2 are tested:
[0040] (1) Experiment on the coefficient of thermal conductivity: According to the test
method of ASTM E 1461-07, a laser flash method is used to test the coefficient of
thermal conductivity of a magnesium alloy wafer having a diameter of 12.7 mm and a
thickness of 3 mm.
[0041] (2) Experiment on tensile properties: According to the test method of ISO 6892-1,
the smelted magnesium alloy melt is injected into a mold cavity by using pressure
casting equipment to obtain a tensile casting with a wall thickness of 3 mm. A universal
mechanical testing machine is used to perform the experiment on tensile properties
to obtain a yield strength and an elongation. The yield strength is a yield limit
when a 0.2% residual deformation is produced. The elongation is elongation at break.
[0042] Experimental results of Embodiments 1 to 4 and Comparative Examples 1 and 2 are shown
in Table 1.
Table 1
|
Embodiment 1 |
Embodiment 2 |
Embodiment 3 |
Embodiment 4 |
Comparative Example 1 |
Comparative Example 2 |
Tensile strength/MPa |
223 |
222 |
224 |
223 |
190 |
230 |
Yield strength/MPa |
155 |
153 |
154 |
152 |
140 |
160 |
Elongation/% |
5 |
5 |
5 |
5 |
3 |
4 |
Coefficient of thermal conductivity/W/(m·K) |
114 |
112 |
110 |
113 |
70 |
75 |
[0043] It can be learned from the data in Table 1 that the magnesium alloys obtained in
Embodiments 1 to 4 have substantially the same mechanical properties as those of the
magnesium alloys in Comparative Examples 1 and 2 and much higher coefficients of thermal
conductivity than those of the magnesium alloys in Comparative Examples 1 and 2. It
indicates that the magnesium alloy in this application has high thermal conductivity
while mechanical properties meeting requirements are ensured.
[0044] The mechanical properties and material molding fluidity of the magnesium alloy prepared
in Embodiment 1 and an AZ91D magnesium alloy are tested. The test standard for mechanical
properties is ISO 6892-1. A sample for testing the material molding fluidity is die-cast
at atmospheric pressure by using a mosquito-repellent incense mold, where the mold
temperature is 200°C and the die-casting temperature is 700°C. An injection speed
is 3 circles per second. A second-speed starting position is 140 mm. The length of
the injected mosquito-repellent incense mold is recorded as an analogy of the material
fluidity. Results are respectively shown in Table 2 and Table 3.
Table 2
Alloy |
Tensile strength/MPa |
Yield strength/MPa |
Elongation/% |
Formability |
Embodiment 1 |
>220 |
>150 |
>4 |
High |
AZ91D |
>200 |
>150 |
>3.0 |
High |
Table 3
Alloy |
Length 1 |
Length 2 |
Length 3 |
Length 4 |
Length 5 |
Average value mm |
Embodiment 1 |
1100 |
1090 |
1120 |
1180 |
1100 |
1118 |
AZ91D |
1050 |
980 |
1030 |
1020 |
980 |
1012 |
[0045] It can be learned from the data in Table 2 and Table 3 that, compared with the AZ91D
magnesium alloy, the magnesium alloy with high thermal conductivity in this application
has extremely high thermal conductivity and heat-dissipation capability, as well as
a relatively high tensile strength, yield strength and elongation, and also has high
formability and recovery capability.
[0046] In the description of the specification, the description of reference terms such
as "one embodiment", "some embodiments", "example", "specific example" or "some examples"
means that specific features, structures, materials, or features described with reference
to the embodiment or example are included in at least one embodiment or example of
this application. In the specification, schematic descriptions of the foregoing terms
are not necessarily specific to the same embodiment or example. In addition, the described
specific features, structures, materials, or characteristics may be combined in a
proper manner in any one or more of the embodiments or examples. In addition, a person
skilled in the art may integrate or combine different embodiments or examples and
characteristics of different embodiments or examples described in the specification,
as long as they do not conflict each other.
[0047] Although the embodiments of this application are shown and described above, it can
be understood that, the foregoing embodiments are exemplary, and cannot be construed
as a limitation to this application. Within the scope of the present invention, a
person of ordinary skill in the art may make changes, modifications, replacement,
and variations to the foregoing embodiments.
1. A magnesium alloy with high thermal conductivity, wherein based on the total mass
of the magnesium alloy with high thermal conductivity, the magnesium alloy with high
thermal conductivity comprises: 2.0-4.0 wt% of Al, 0.1-0.3 wt% of Mn, 1.0-2.0 wt%
of La, 2.0-4.0 wt% of Ce, 0.1-1.0 wt% of Nd, 0.5-2.0 wt% of Zn, 0.1-0.5 wt% of Ca,
less than 0.1 wt% of Sr, less than 0.1 wt% of Cu, and magnesium.
2. The magnesium alloy with high thermal conductivity according to claim 1, wherein based
on the total mass of the magnesium alloy with high thermal conductivity, the magnesium
alloy with high thermal conductivity comprises: 0.15-0.3 wt% of Mn and 2.5-4.0 wt%
of Ce.
3. The magnesium alloy with high thermal conductivity according to claim 1 or 2, wherein
based on the total mass of the magnesium alloy with high thermal conductivity, the
magnesium alloy with high thermal conductivity comprises:
3.0 wt% of Al, 0.25 wt% of Mn, 1.55 wt% of La, 3.0 wt% of Ce, 0.13 wt% of Nd, 0.6
wt% of Zn, 0.15 wt% of Ca, less than 0.1 wt% of Sr, less than 0.1 wt% of Cu, and magnesium.
4. The magnesium alloy with high thermal conductivity according to claim 1 or 2, wherein
based on the total mass of the magnesium alloy with high thermal conductivity, the
magnesium alloy with high thermal conductivity comprises:
2.0 wt% of Al, 0.15 wt% of Mn, 2.0 wt% of La, 2.5 wt% of Ce, 0.1 wt% of Nd, 2.0 wt%
of Zn, 0.1 wt% of Ca, less than 0.1 wt% of Sr, less than 0.1 wt% of Cu, and magnesium.
5. The magnesium alloy with high thermal conductivity according to claim 1 or 2, wherein
based on the total mass of the magnesium alloy with high thermal conductivity, the
magnesium alloy with high thermal conductivity comprises:
4.0 wt% of Al, 0.1 wt% of Mn, 1.0 wt% of La, 2.0 wt% of Ce, 1.0 wt% of Nd, 0.5 wt%
of Zn, 0.5 wt% of Ca, less than 0.1 wt% of Sr, less than 0.1 wt% of Cu, and magnesium.
6. The magnesium alloy with high thermal conductivity according to claim 1 or 2, wherein
based on the total mass of the magnesium alloy with high thermal conductivity, the
magnesium alloy with high thermal conductivity comprises:
2.5 wt% of Al, 0.3 wt% of Mn, 1.0 wt% of La, 4.0 wt% of Ce, 0.5 wt% of Nd, 0.5 wt%
of Zn, 0.3 wt% of Ca, less than 0.1 wt% of Sr, less than 0.1 wt% of Cu, and magnesium.
7. The magnesium alloy with high thermal conductivity according to any one of claims
1 to 6, wherein the thermal conductivity is greater than 110 w/m·K.
8. The magnesium alloy with high thermal conductivity according to any one of claims
1 to 7, wherein at least one of the following conditions is met:
a tensile strength is greater than 220 MPa;
a yield strength is greater than 150 MPa; and
an elongation is greater than 4%.
9. An inverter housing, wherein at least a part of the inverter housing is formed by
the magnesium alloy with high thermal conductivity according to any one of claims
1 to 8.
10. An inverter, comprising the inverter housing according to claim 9.
11. A vehicle, comprising the inverter according to claim 10.