Field of the Invention
[0001] The present invention relates generally to titanium alloys, and more particularly,
to a new titanium alloy and method for making the same which can be manufactured from
recycled titanium.
Background of the Invention
[0002] Titanium alloys offer attractive combinations of physical and mechanical properties
which make them ideal for applications requiring high strength, low weight, and good
corrosion properties. However, titanium alloys are expensive to manufacture, which
severely limits their application. A number of processing steps are required to refine
titanium from its raw form to a usable form. In addition, because of its highly reactive
nature, the refining process must be carefully controlled, further increasing manufacturing
costs. As a result, the use of titanium is typically limited to military vehicles,
airplane engine and air-frame components, chemical processing, and sports hardware.
[0003] It is desirable to use recycled titanium to reduce manufacturing costs. However,
the ability to use recycled materials is limited. To obtain the desired strength and
ductility, the oxygen content of most conventional medium and high strength titanium
alloys is typically limited to 0.2 percent by weight of the alloy. This relatively
low oxygen limit makes it difficult to use recycled titanium materials. During the
recycling process, the titanium materials are exposed to air while being melted and
subsequently cooled. As a result they tend to absorb oxygen and other interstitial
elements each time they are recycled.
[0004] As a result, a need has arisen for a new titanium alloy and a method of making the
same.
Summary of the Preferred Embodiments
[0005] In accordance with one aspect of the present invention, a titanium alloy is provided.
The alloy comprises titanium and one or more elements selected from the group consisting
of chromium, manganese, and iron, wherein in an as-cast condition, the alloy has a
yield strength of at least about 135,000 psi.
[0006] The alloy preferably comprises aluminum in a range of about 3.5 to about 6.25 percent
by weight of the alloy, with ranges of about 4.5 to about 6.0 percent and about 5.0
to about 6.0 percent being more preferred and especially preferred, respectively.
In a preferred embodiment, the alloy comprises vanadium in a range of about 3.0 to
about 4.5 percent by weight of the alloy, with ranges of about 3.3 to about 4.5 percent
and about 3.5 to about 4.5 percent being more preferred and especially preferred,
respectively. In accordance with another preferred embodiment, the amount of chromium
is in a range of up to about 3.8 percent by weight of the alloy, with ranges of about
1.0 to about 2.5 percent and about 1.2 to about 2.0 percent being more preferred and
especially preferred, respectively. In other preferred embodiments, the amount of
manganese is in a range of up to about 2.0 percent by weight of the alloy, with ranges
of up to about 1.5 percent and about 0.75 to about 1.25 percent being more preferred
and especially preferred, respectively.
[0007] In yet other preferred embodiments, the alloy comprises oxygen in a range of up to
about 0.3 percent by weight, with ranges of up to about 0.29 percent and up to about
0.27 percent being more preferred and especially preferred, respectively. It is further
preferred that the combined amount of chromium, manganese, and iron is in a range
of about 1.0 to about 5.0 percent by weight of the alloy, with ranges of about 1.0
to about 4.5 percent and about 2.0 to about 3.5 percent being more preferred and especially
preferred, respectively.
[0008] In accordance with another aspect of the present invention, a titanium alloy is provided.
The alloy comprises aluminum, in a range of about 3.5 to about 6.25 percent by weight
of the alloy; vanadium, in a range of about 3.0 to about 4.5 percent by weight of
the alloy; and one or more elements selected from the group consisting of chromium,
iron, and manganese, wherein the one or more elements are present in a range of about
1.0 to about 5.0 percent by weight of the alloy. Titanium is present in a remaining
amount, and in an as-cast condition, the alloy preferably has a yield strength of
at least about 135,000 psi.
[0009] The amount of aluminum is more preferably in a range of about 4.5 to about 6.0 percent
by weight of the alloy, with a range of about 5.0 to about 6.0 percent being especially
preferred. The amount of vanadium is more preferably in a range of about 3.3 to about
4.5 percent by weight of the alloy, with a range of about 3.5 to about 4.5 percent
being especially preferred. The amount of chromium in the alloy is preferably in a
range of up to about 3.8 percent by weight of the alloy, with ranges of about 1.0
to about 2.5 percent and about 1.2 to about 2.0 percent being more preferred and especially
preferred, respectively. The amount of manganese is preferably in a range of up to
about 2.0 percent by weight of the alloy, with ranges of up to about 1.5 percent and
about 0.75 to about 1.25 percent being more preferred and especially preferred, respectively.
The amount of iron is preferably in a range of up to about 1.0 percent by weight of
the alloy. The amount of oxygen is preferably in a range of up to about 0.3 percent
by weight of the alloy, with ranges of up to about 0.29 percent and up to about 0.27
percent being more preferred and especially preferred, respectively. The alloy preferably
has a tensile strength of at least about 155,000 psi and a percent elongation of at
least about 5.0 percent.
[0010] In accordance with yet another aspect of the present invention, a titanium alloy
is provided which comprises chromium, in an range of up to about 3.8 percent by weight
of the alloy; iron, in a range of up to about 1.0 percent by weight of the alloy;
and manganese, in a range of about 0.75 to about 1.25 percent by weight of the alloy,
wherein the combined amount of chromium, iron, and manganese is in a range of about
1.0 to about 5.0 percent by weight of the alloy. Titanium is present in a remaining
amount.
[0011] In accordance with still another aspect of the present invention, a titanium alloy
is provided which comprises aluminum in a range of about 3.5 to about 6.25 percent
by weight of the alloy; vanadium, in a range of about 3.0 to about 4.5 percent by
weight of the alloy; chromium, in range of up to about 3.8 percent by weight of the
alloy; manganese, in a range of up to about 2.0 percent by weight of the alloy; iron,
in a range of up to about 1.0 percent by weight of the alloy; oxygen, in a range of
more than about 0.2 to about 0.3 percent by weight of the alloy; and titanium in a
remaining amount, wherein the combined amount of chromium, manganese, and iron is
in a range of about 2.0 to about 3.5 percent by weight of the alloy.
[0012] In accordance with another aspect of the present invention, a method of making a
titanium alloy is provided. The method comprises combining a titanium material with
one or more elements selected from the group consisting of chromium, manganese, and
iron, wherein in an as-cast condition, the titanium alloy has a yield strength of
at least about 135,000 psi. In a preferred embodiment, the combined amount of chromium,
manganese, and iron in the alloy is in a range of about 1.0 to about 5.0 percent by
weight of the alloy. In still other preferred embodiments, the combined amount of
chromium, manganese, and iron in the alloy is in a range of about 2.0 to about 3.5
percent by weight of the alloy.
[0013] Preferably, the alloy comprises oxygen in range of up to about 0.3 percent by weight
of the alloy. Even more preferably, the amount of oxygen in the alloy is greater than
about 0.2 percent by weight of the alloy. In another preferred embodiment, the amount
of manganese in the alloy is in a range of about 0.75 to about 1.25 percent of the
alloy. In additional preferred embodiments, the amount of chromium in the alloy is
in a range of up to about 3.8 percent by weight of the alloy, with a range of about
1.0 to about 2.5 percent being more preferred. In other preferred embodiments, the
amount of iron in the alloy is in a range of up to about 1.0 percent by weight of
the alloy.
[0014] In a preferred embodiment, the titanium material is a recycled titanium material.
In other preferred embodiments, the titanium material is a Ti-6Al-4V material. In
yet other preferred embodiments, the titanium material is a commercially pure titanium
material. In still other preferred embodiments, the titanium material is a Ti-3Al-2,5Al
material.
[0015] In accordance with an additional aspect of the present invention, a method of making
a titanium alloy is provided which comprises providing a titanium material and combining
it with manganese, such that the amount of manganese in the alloy is in a range of
about 0.75 to about 1.25 percent by weight of the alloy; chromium, such that the amount
of chromium in the alloy is in an range of up to about 3.8 percent by weight of the
alloy; and iron, such that the amount of iron in the alloy is in an range of up to
about 1.0 percent by weight of the alloy, wherein the combined amount of chromium,
manganese, and iron in the alloy is in a range of about 1.0 to about 5.0 percent by
weight of the alloy.
Detailed Description of the Preferred Embodiments
[0016] The present invention is directed to titanium alloys that can be produced from recycled
commercial titanium alloys. As indicated in Table 1, in order to maintain desirable
strength and ductility, commercial titanium alloys are typically limited to an oxygen
content of no more than 0.2 percent by weight of the alloy.
Table 1--Conventional Titanium alloys
| Alloy |
Al |
V |
Mo |
Sn |
Zr |
Cr |
Fe |
Mn |
O |
| Ti-6Al-4V |
5.5-6.75 |
3.5-4.5 |
|
|
|
|
0.3 max |
|
0.2 max |
| Ti-6Al-2Sn-2Mo-2Zr-2Cr |
5.25-6.25 |
|
1.75-2.25 |
1.75-2.25 |
1.75-2.25 |
1.75-2.25 |
|
|
0.13 max |
| Ti-6Al-2Sn-4Zr-6Mo |
5.5-6.5 |
|
5.5-6.5 |
1.75-2.25 |
3.5-4.5 |
|
0.15 max |
|
0.15 max |
| Ti-15V-3Cr-3Al-3Sn |
2.5-3.5 |
14.0-1about 6.0 |
|
2.5-3.5 |
|
2.5-3.5 |
0.25 max |
|
0.13 max |
| Ti-10V-2Fe-3Al |
2.6-3.4 |
9.0-11.0 |
|
|
|
|
1.6-2.2 |
|
0.13 max |
[0017] As is known to those skilled in the art, at temperatures below approximately 880°C,
titanium assumes a close-packed hexagonal structure referred to as the "alpha" phase.
At temperatures of 880°C and above, titanium assumes a body centered cubic structure
known as the "beta" phase. It has been found that by adding at least one beta-eutectoid
stabilizing element, preferably one selected from the group consisting of chromium,
iron and manganese, titanium alloys of the present invention can tolerate higher levels
of oxygen, and therefore, can be manufactured from increased amounts of recycled materials.
Alloys of the present invention preferably have yield strengths of at least about
135,000 psi, tensile strengths of at least about 155,000 psi and percent elongation
values of at least about 5 percent.
[0018] The base titanium material used to form alloys of the present invention is preferably
a Ti-3Al-2,5V alloy, a Ti-6Al-4V alloy or commercially pure titanium. As used herein,
the term "commercially pure titanium" refers to a titanium material in which the amount
of titanium is at least about 98 percent by weight of the material. Ti-6Al-4V alloys
and commercially pure titanium are abundantly available in various forms, including
electrodes, scrap and plate material and are readily available for recycling.
[0019] A first preferred embodiment of the present invention will now be described. According
to this embodiment, the alloy preferably comprises aluminum in a range of about 3.5
to about 6.25 percent by weight of the alloy. A range of about 4.5 to about 6.0 percent
is more preferred, and a range of about 5.0 to about 6.0 percent is especially preferred.
Aluminum is an alpha-phase stabilizer which helps increase alloy strength. As is known
to those skilled in the art, Rosenberg's empirical formula describes a relationship
between titanium alloying elements which can be used to prepare alloys having good
ductility, strength and metallurgical stability. In particular, it is used to develop
high temperature titanium alloys having maximum aluminum equivalents. Rosenberg's
formula is as follows:

[0020] In accordance with this embodiment, the alloy preferably contains no tin or zirconium.
It is especially preferred that the aluminum content not exceed about 6.0 percent
aluminum, because in the absence of tin and zirconium, such an alloy will satisfy
Rosenberg's formula at oxygen levels of up to 0.3 percent by weight of the alloy.
[0021] In accordance with this embodiment, the alloy preferably contains vanadium in a range
of about 3.0 to about 4.5 percent by weight of the alloy. Vanadium is a beta-isomorphous
stabilizer which is used to increase the strength of the alloy. The ratio of vanadium
to aluminum may impact the alloy's phase balance and is preferably maintained at a
level which allows for optimization of mechanical properties by precipitation hardening
alpha-beta and metastable beta titanium alloys.
[0022] The alloy also preferably contains at least one beta-eutectoid stabilizing element
selected from the group consisting of chromium, iron and manganese. The combined amount
of chromium, iron, and manganese is preferably in a range of about 1.0 to about 5.0
percent by weight of the alloy. A range of about 1.0 to about 4.5 percent is more
preferred, and a range of about 2.0 to about 3.5 percent is especially preferred.
[0023] Chromium is preferably present in a range of up to about 3.8 percent by weight of
the alloy. A chromium range of about 1.0 to about 2.5 percent is more preferred, and
a range of about 1.2 to about 2.0 percent is especially preferred.
[0024] In accordance with this embodiment, iron is preferably present in a range of up to
about 1.0 percent by weight. Manganese is preferably present in a range of up to about
2.0 percent by weight of the alloy. A manganese range of up to about 1.5 percent is
more preferred, and a range of about 0.75 to about 1.25 percent by weight is especially
preferred. It has been found that adding Manganese in the foregoing levels improves
alloy strength.
[0025] Chromium, iron, and manganese are effective beta-eutectoid stabilizers. They are
used to increase strength and control ductility and the alloy's response to thermal
treatment. They are easy to melt and can be added in their elemental forms. As a result,
they are relatively inexpensive to process. Although all three elements are beta-eutectoid
stabilizers, it has been found that combining them is especially preferred for obtaining
alloys with excellent strength and ductility from recycled titanium materials.
[0026] As explained previously, it has been found that the addition of the foregoing beta-eutectoid
stabilizing elements allows the alloys of the present invention to tolerate increased
oxygen levels while still maintaining excellent ductility. In accordance with this
embodiment, oxygen is present in a range of up to about 0.3 percent by weight of the
alloy. Oxygen ranges of up to 0.29 percent are more preferred, and an oxygen range
of up to about 0.27 percent is especially preferred. The ability of alloys of this
embodiment to tolerate such levels of oxygen allows them to be manufactured from increased
amounts of recycled titanium materials. In addition, the increased levels of oxygen
improve alloy ductility.
[0027] In accordance with this embodiment, other elements may also be present. Preferably,
nitrogen levels are not more than about 0.05 percent by weight of the alloy. Nitrogen
levels of not more than about 0.04 percent are more preferred, and nitrogen levels
of not more than about 0.035 percent are especially preferred. The alloy preferably
contains carbon levels of not more than about 0.1 percent by weight of the alloy.
Carbon levels of not more than about 0.05 percent are more preferred, and carbon levels
of not more than about 0.03 are especially preferred.
[0028] Hydrogen levels are preferably maintained at not more than about 150 ppm of the alloy
weight. Hydrogen levels of not more than about 125 ppm are especially preferred. If
present, it is preferred that any elements other than the foregoing are present in
amounts of not more than about 0.1 percent by weight each, with their combined amounts
not exceeding 0.4 percent by weight. For ease of reference, set forth below in Table
2 are the preferred, most preferred, and especially preferred ranges of ingredients
used in this embodiment of the present invention:
Table 2 Ranges of elements as weight percent of alloy
| Element |
Preferred Range |
More Preferred Range |
Especially Preferred Range |
| aluminum |
about 3.5-about 6.25 |
about 4.5-about 6.0 |
about 5.0-about 6.0 |
| vanadium |
about 3.0-about 4.5 |
about 3.3-about 4.5 |
about 3.5-about 4.5 |
| chromium |
up to about 3.8 |
about 1.0 to about 2.5 |
about 1.2 to about 2.0 |
| manganese |
up to about 2.0 |
up to about 1.5 |
about 0.75-about 1.25 |
| iron |
up to about 1.0 |
up to about 1.0 |
up to about 1.0 |
| oxygen |
up to about 0.3 |
up to about 0.29 |
up to about 0.27 |
| nitrogen |
not more than about 0.05 |
not more than about 0.04 |
not more than about 0.035 |
| hydrogen |
not more than about 150 ppm |
not more than about 125 ppm |
not more than about 125 ppm |
| carbon |
not more than about 0.1 |
not more than about 0.05 |
not more than about 0.03 |
| others, each |
not more than about 0.1 |
not more than about 0.1 |
not more than about 0.1 |
| others, total |
not more than about 0.4 |
not more than about 0.4 |
not more than about 0.4 |
| Cr+Mn+Fe |
about 1.0 to about 5.0 |
about 1.0 to about 4.5 |
about 2.0 to about 3.5. |
[0029] In their as-cast condition, alloys prepared in accordance with this embodiment will
preferably have a tensile strength of at least about 135,000 psi. They will also preferably
have a yield strength of at least about 155,000 psi and a percent elongation of at
least about 5.0 percent. As used herein, the term "as-cast" refers to the condition
of the alloy following casting but prior to any heat treatment, annealing, forming,
or any other thermo-mechanical treatment. It is expected that wrought products which
have undergone such processes will have even higher yield strengths, tensile strengths
and percent elongation values.
[0030] An embodiment of a method of making a titanium alloy in accordance with the present
invention will now be described. According to this embodiment, a pre-existing commercially
pure titanium material, which is preferably recycled or scrap titanium, is provided.
In this embodiment, Grade 1 commercially pure titanium designated as UNS (Unified
Numbering System) R50250 is used. In addition to titanium, R50250 comprises 0.20 weight
percent iron and 0.18 weight percent oxygen. Because it is recycled, however, the
oxygen level will be higher than that of virgin R50250 material.
[0031] According to this embodiment, the R50250 material is melted and combined with an
aluminum/vanadium master alloy. Preferably, the amount of aluminum in the Al/V master
alloy is such that the aluminum composition in the titanium alloy is in a range of
about 3.5 to about 6.25 percent by weight of the alloy. The amount of vanadium in
the Al/V master alloy is preferably such that the vanadium composition of the titanium
alloy is in a range of about 3.0 to about 4.5 percent by weight of the alloy. At least
one beta-eutectoid stabilizer selected from the group consisting of chromium, iron
and manganese is added such that their combined amount in the alloy is in a range
of about 1.0 to about 5.0 percent by weight of the alloy. The amount of chromium in
the alloy is preferably in a range of up to about 3.8 percent by weight of the alloy,
and the amount of manganese in the alloy is preferably in a range of up to about 2.0
percent by weight of the alloy. The amount of iron in the alloy is preferably in a
range of up to about 1.0 percent by weight of the alloy. The amount of oxygen in the
alloy is preferably in a range of up to about 0.3 percent by weight of the alloy.
Oxygen levels are preferably controlled by selecting scrap titanium or sponge with
suitably low oxygen content. If present, carbon, hydrogen, nitrogen and additional
impurities are preferably kept within the ranges specified in the "preferred range"
in Table 1. Levels of these elements in the alloy are also preferably controlled by
selecting recycled titanium materials with suitably low levels of them.
[0032] It is more preferable to add amounts of aluminum, vanadium, chromium, manganese and
iron which yield the weight percentages specified in the "more preferred range" column
of Table 2 and to control the levels of oxygen, nitrogen, hydrogen, carbon and other
impurities in the alloy to the levels specified in the more preferred range column.
It is especially preferred that alloys prepared in accordance with this embodiment
contain the amounts of the foregoing elements listed in the "especially preferred
range" column of Table 2. Alloys prepared according to the method of this embodiment
will preferably have a yield strength of at least about 135,000 psi, a tensile strength
of at least about 155,000 psi, and a percent elongation of at least about 5.0 percent.
[0033] In accordance with another embodiment of the present invention, a method of preparing
a titanium alloy from a pre-existing Ti-6Al-4V material is provided. The Ti-6Al-4V
material is preferably a recycled or scrap material. Commercially produced Ti-6Al-4V
contains 5.5 to 6.75 percent by weight aluminum, 3.5 percent to 4.5 percent by weight
vanadium, up to 0.3 percent by weight iron, and up to 0.2 percent by weight oxygen.
However, due to the use of recycled material, the oxygen content will typically exceed
0.2 percent. In accordance with this embodiment, the aluminum content in the Ti-6Al-4V
will preferably not exceed about 6.0 percent by weight of the alloy.
[0034] At least one beta-eutectoid stabilizer selected from the group consisting of chromium,
manganese, and iron is combined with the Ti-6Al-4V material such that the combined
amount of chromium, manganese, and iron is within the preferred range specified in
Table 2. It is more preferred to use the range specified in the more preferred column
of Table 2 and especially preferred to use the range specified in the especially preferred
column of Table 2. Oxygen, carbon, hydrogen, nitrogen, and other impurities are also
preferably kept within the ranges specified in Table 2. Alloys prepared according
to the method of this embodiment will preferably have a yield strength of at least
about 135,000 psi, a tensile strength of at least about 155,000 psi, and a percent
elongation of at least about 5.0 percent.
[0035] According to another embodiment of the present invention, a method of making a titanium
alloy from a pre-existing Ti-3Al-2,5V alloy is provided. The alloy is preferably recycled.
According to this embodiment, aluminum and vanadium are combined with the recycled
Ti-3Al-2,5V material such that the resulting alloy contains aluminum in a range of
about 3.5 to about 6.25 percent by weight of the alloy and vanadium in a range of
about 3.0 to about 4.5 percent by weight of the alloy. At least one beta-eutectoid
stabilizer selected from the group consisting of chromium, manganese, and iron is
added such that their combined amounts in the alloy are in a range of about 1.0 to
about 5.0 percent by weight of the alloy. Preferably, the alloy has an oxygen content
in a range of up to about 0.3 percent by weight of the alloy. The remaining preferred,
more preferred, and especially preferred values for the various elements in Table
2 are applicable to this method as well.
[0036] The invention may be better understood by referring to the following examples of
titanium alloys prepared in accordance with the present invention. All samples were
heat treated by hipping (hot isostatically pressing) at 1650°F and 15,000 ± 500 psi
for 2 hours followed by aging in a range of from 900°F to 1100°F for periods of from
4 to 12 hours.
Table 3--Examples
| Element |
Sample 1 |
Sample 2 |
Sample 3 |
Sample 4 |
Sample 5 |
Sample 6 |
Sample 7 |
Sample 8 |
| Al |
5.81 |
5.76 |
5.5 |
5.8 |
5.89 |
5.7 |
5.44 |
5.62 |
| V |
3.77 |
3.73 |
3.69 |
3.8 |
3.71 |
3.7 |
3.64 |
3.83 |
| Cr |
1.37 |
2.22 |
1.8 |
1.16 |
1.15 |
1.93 |
1.28 |
-- |
| Mn |
- - |
- - |
1.03 |
- - |
1.15 |
1.58 |
0.98 |
1.84 |
| Fe |
0.19 |
0.15 |
0.17 |
0.12 |
0.17 |
0.014 |
0.96 |
0.17 |
| O |
0.27 |
0.26 |
0.27 |
0.24 |
0.27 |
0.29 |
0.28 |
0.29 |
| N |
0.022 |
0.02 |
0.023 |
0.018 |
0.024 |
0.03 |
0.038 |
0.03 |
| H |
0.0029 |
0.007 |
0.0075 |
0.0037 |
0.0049 |
0.0014 |
0.0034 |
0.0015 |
| C |
0.02 |
0.02 |
0.02 |
0.02 |
0.02 |
0.01 |
0.02 |
0.01 |
| Ti |
bal. |
bal. |
bal. |
bal. |
bal. |
bal. |
bal. |
bal. |
| |
|
|
|
|
|
|
|
|
| Condition |
as cast |
as cast |
as cast |
as cast |
as cast |
as cast |
as cast |
as cast |
| YS, ksi |
138 |
143 |
143 |
136 |
145 |
|
|
149 |
| UTS, ksi |
161 |
164 |
164 |
159 |
166 |
|
|
169 |
| % elong. |
8.5 |
8.5 |
7.5 |
9.5 |
6.5 |
|
|
7 |
| % RA |
19 |
23 |
18 |
17 |
17 |
|
|
14 |
| |
|
|
|
|
|
|
|
|
| Condition |
heat treat |
heat treat |
heat treat |
heat treat |
heat treat |
heat treat |
heat treat |
heat treat |
| YS, ksi |
144 |
146 |
150 |
145 |
150 |
152 |
153 |
149 |
| UTS, ksi |
160 |
162 |
165 |
165 |
171 |
167 |
165 |
164 |
| % elong. |
9.5 |
11 |
10 |
9 |
7 |
9 |
8 |
7.5 |
| % RA |
23 |
22 |
22 |
15 |
14 |
17 |
21 |
16.5 |
| Key: bal.= balance, YS=yield strength, ksi=1000 lb/(.in)2, UTS=Ultimate Tensile Strength, % elong.= percent elongation, % RA= percent reduction
in area. The term "heat treat" refers to the material following heat treating. |
[0037] As the data indicates, the alloys in Table 3 all had oxygen levels well above the
conventional limit of 0.2 weight percent, yet attained as-cast yield strengths of
greater than 135,000 psi, tensile strengths of greater than 155,000 psi, and percent
elongation values of greater than 5%. In addition, strength and ductility were further
improved with heat treating.
[0038] Table 4 provides a comparison of the yield strength, tensile strength, and percent
elongation of certain of the alloys in Table 3 with several commercial alloys:
Table 4 Comparison of Commercial Alloys to Embodiments of the Present Invention
| Alloy and condition |
YS ksi |
UTS ksi |
% elongation |
| Ti-6Al-4V (cast and heat treated) |
120 |
134 |
8 |
| Ti-6Al-4V (wrought mill annealed) |
137 |
151 |
14 |
| Ti-6Al-2Sn-2Mo-2Zr-2Cr (cast and heat treated) |
131 |
155 |
5 |
| BT-22 (cast and heat treated) |
151 |
151 |
1.5 |
| Sample 1 (cast and heat treated) |
144 |
160 |
9.5 |
| Sample 3 (cast and heat treated) |
150 |
165 |
10 |
| Sample 7 (cast and heat treated) |
153 |
165 |
8 |
| Sample 8 (cast and heat treated) |
149 |
164 |
7.5 |
[0039] As indicated in Table 4, the samples prepared in accordance with the foregoing embodiments
of the present invention achieved yield and tensile strengths comparable or superior
to those found in virgin Ti-6Al-4V and Ti-6Al-2Sn-2Mo-2Zr-2Cr, while tolerating significantly
higher oxygen levels (See Tables 1 and 3). As a result of their increased oxygen tolerance,
alloys of the present invention can be manufactured from greater amounts of recycled
materials than alloys with lower oxygen tolerances.
[0040] The embodiments described above are exemplary embodiments of a the present invention.
Those skilled in the art may now make numerous uses of, and departures from, the above-described
embodiments without departing from the inventive concepts disclosed herein. Accordingly,
the present invention is to be defined solely by the scope of the following claims.
1. A titanium alloy, comprising:
aluminum, in a range of about 3.5 to about 6.25 percent by weight of the alloy;
vanadium, in a range of about 3.0 to about 4.5 percent by weight of the alloy;
one or more elements selected from the group consisting of chromium, iron, and manganese,
wherein said one or more elements are present in a range of about 1.0 to about 5.0
percent by weight of the alloy;
titanium being present in a remaining amount;
wherein in an as-cast condition, the alloy has a yield strength of at least about
135,000 psi.
2. The alloy of claim 1, wherein in an as-cast condition, the alloy has a tensile strength
of at least about 155,000 psi.
3. The alloy of claim 1, wherein in an as-cast condition, the alloy has a percent elongation
of at least about 5 percent.
4. The alloy of claim 1, wherein the amount of chromium is in a range of about 1.0 to
about 2.5 percent by weight of the alloy.
5. The alloy of claim 1, wherein the amount of chromium is in a range of about 1.2 to
about 2.0 percent by weight of the alloy.
6. The alloy of claim 1, wherein the amount of manganese is in a range of up to about
2.0 percent by weight of the alloy.
7. The titanium alloy of claim 1, wherein the amount of manganese is in a range of about
0.75 to about 1.25 percent by weight of the alloy.
8. The titanium alloy of claim 1, wherein the amount of iron is in a range of up to about
1.0 percent by weight of the alloy.
9. The titanium alloy of claim 1, wherein the amount of aluminum is in a range of about
5.0 to about 6.0 percent by weight of the alloy.
10. The titanium alloy of claim 1, wherein the amount of vanadium is in a range of about
3.3 to about 4.5 percent by weight of the alloy.
11. The titanium alloy of claim 1, wherein the combined amount of chromium, manganese,
and iron is in a range of about 2.0 percent to about 3.5 percent by weight of the
alloy.
12. The titanium alloy of claim 1, further comprising oxygen in a range of up to about
0.3 percent by weight of the alloy.
13. A titanium alloy, comprising:
titanium; and
one or more elements selected from the group consisting of chromium, manganese, and
iron, wherein in an as-cast condition, the alloy has a yield strength of at least
about 135,000 psi.
14. The titanium alloy of claim 13, further comprising aluminum.
15. The titanium alloy of claim 14, wherein the amount of aluminum is in a range of about
3.5 to about 6.25 percent by weight of the alloy.
16. The titanium alloy of claim 13, further comprising vanadium.
17. The titanium alloy of claim 16, wherein the amount of vanadium is in a range of about
3.0 to about 4.5 percent by weight of the alloy.
18. The titanium alloy of claim 13, wherein the amount of chromium is in a range of up
to about 3.8 percent by weight of the alloy.
19. The titanium alloy of claim 13, further comprising oxygen.
20. The titanium alloy of claim 19, wherein the amount of oxygen is in a range of up to
about 0.3 percent by weight of the alloy.
21. The titanium alloy of claim 13, wherein the amount of manganese is in a range of up
to about 2.0 percent by weight of the alloy.
22. The titanium alloy of claim 13, wherein the amount of manganese is in a range of about
0.75 to about 1.25 percent by weight of the alloy.
23. The titanium alloy of claim 13, wherein the amount of chromium is in a range of about
1.0 to about 2.5 percent by weight of the alloy.
24. The titanium alloy of claim 13, wherein the amount of iron is in a range of up to
about 1.0 percent by weight of the alloy.
25. The titanium alloy of claim 13, wherein the combined amount of chromium, manganese,
and iron is in a range of about 1.0 to about 5.0 percent by weight of the alloy.
26. The titanium alloy of claim 13, wherein the combined amount of chromium, manganese,
and iron is in a range of about 2.0 to about 3.5 percent by weight of the alloy.
27. The titanium alloy of claim 13, wherein in an as-cast condition, the alloy has a tensile
strength of at least about 155,000 psi.
28. The titanium alloy of claim 13, wherein in an as-cast condition, the alloy has a percent
elongation of at least about 5.0 percent.
29. A method of making a titanium alloy, comprising:
combining a titanium material with one or more elements selected from the group consisting
of chromium, manganese, and iron,
wherein in an as-cast condition, the titanium alloy has a yield strength of at least
about 135,000 psi.
30. The method of claim 29, wherein the combined amount of chromium, manganese, and iron
in the alloy is in a range of about 1.0 to about 5.0 percent by weight of the alloy.
31. The method of claim 29, wherein the combined amount of chromium, manganese, and iron
in the alloy is in a range of about 2.0 to about 3.5 percent by weight of the alloy.
32. The method of claim 29, wherein the alloy comprises oxygen in a range of up to about
0.3 percent by weight of the alloy.
33. The method of claim 32, wherein the amount of oxygen in the alloy is greater than
about 0.2 percent by weight of the alloy.
34. The method of claim 29, wherein the amount of manganese in the alloy is in a range
of up to about 2 percent by weight of the alloy.
35. The method of claim 29, wherein the amount of manganese in the alloy is in a range
of about 0.75 to about 1.25 percent by weight of the alloy.
36. The method of claim 29, wherein the amount of chromium in the alloy is in a range
of up to about 3.8 percent by weight of the alloy.
37. The method of claim 29, wherein the amount of chromium in the alloy is in a range
of about 1.0 to about 2.5 percent by weight of the alloy.
38. The method of claim 29, wherein the amount of iron in the alloy is in a range of up
to about 1.0 percent by weight of the alloy.
39. The method of claim 29, wherein the titanium material is a recycled titanium material.
40. The method of claim 29, wherein the titanium material is a Ti-6Al-4V material.
41. The method of claim 29, wherein the titanium material is a commercially pure titanium
material.
42. The method of claim 41, further comprising the step of combining aluminum with the
titanium material, wherein the amount of aluminum in the alloy is in a range of about
3.5 to about 6.25 percent by weight of the alloy.
43. The method of claim 41, further comprising the step of combining vanadium with the
titanium material, wherein the amount of vanadium in the alloy is in a range of about
3.0 to about 4.5 percent by weight of the alloy.
44. The method of claim 29, wherein the titanium material is a Ti-3Al-2,5V material.
45. The method of claim 44, further comprising the step of combining aluminum with the
titanium material, wherein the amount of aluminum in the alloy is in a range of about
3.5 to about 6.25 percent by weight of the alloy.
46. The method of claim 44, further comprising the step of combining vanadium with the
titanium material, wherein the amount of vanadium in the alloy is in a range of about
3.0 to about 4.5 percent by weight of the alloy.
47. The method of claim 29, wherein the titanium material is scrap titanium material.
48. The method of claim 29, wherein the titanium material comprises aluminum in a range
of about 3.5 to about 6.25 percent by weight of the alloy.
49. The method of claim 29, wherein the titanium material comprises vanadium in a range
of about 3.0 to about 4.5 percent by weight of the alloy.
50. The method of claim 29, wherein in an as-cast condition, the alloy has a tensile strength
of at least about 155,000 psi.
51. The method of claim 29, wherein in an as-cast condition, the alloy has a percent elongation
of at least about 5.0 percent.
52. A method of making a titanium alloy, comprising:
providing a titanium material comprising aluminum in a range of about 3.5 to about
6.25 percent by weight of the alloy, oxygen in a range of up to about 0.3 percent
by weight and vanadium in a range of about 3.0 to about 4.5 percent by weight of the
alloy;
combining the titanium material with manganese, such that the amount of manganese
in the alloy is in a range of about 0.75 to about 2.0 percent by weight of the alloy,
chromium, such that the amount of chromium in the alloy is in a range of up to about
3.8 percent by weight of the alloy, and iron, such that the amount of iron in the
alloy is in a range of up to about 1.0 percent by weight of the alloy, wherein the
combined amount of manganese, chromium, and iron in the alloy is in a range of about
1.0 to about 5.0 percent by weight of the alloy.
53. The method of claim 52, wherein the combined amount of manganese, chromium, and iron
in the alloy is in a range of about 2.0 to about 3.5 percent by weight of the alloy.
54. The method of claim 52, wherein the amount of chromium in the alloy is in a range
of about 1.0 to about 2.5 percent by weight of the alloy.
55. The method of claim 52, wherein in an as-cast condition, the alloy has a yield strength
of at least about 135,000 psi.
56. The method of claim 52, wherein in an as-cast condition, the alloy has a tensile strength
of at least about 155,000 psi.
57. The method of claim 52, wherein in an as-cast condition, the alloy has a percent elongation
of at least about 5.0 percent.
58. A titanium alloy, comprising:
chromium, in a range of up to about 3.8 percent by weight of the alloy;
iron, in a range of up to about 1.0 percent by weight of the alloy;
manganese, in a range of about 0.75 to about 1.25 percent by weight of the alloy;
titanium, being present in a remaining amount;
wherein the combined amount of chromium, iron and manganese is in a range of about
1.0 to about 5.0 percent by weight of the alloy.
59. The titanium alloy of claim 58, further comprising oxygen in a range of up to about
0.3 percent by weight of the alloy.
60. The titanium alloy of claim 58, further comprising aluminum in a range of about 3.5
to about 6.25 percent by weight of the alloy.
61. The titanium alloy of claim 58, further comprising vanadium in a range of about 3.0
to about 4.5 percent by weight of the alloy.
62. The titanium alloy of claim 58, wherein the combined amount of chromium, manganese,
and iron is in a range of about 2.0 to about 3.5 percent by weight of the alloy.
63. The titanium alloy of claim 58, wherein in an as-cast condition, the alloy has a yield
strength of at least about 135,000 psi.
64. The titanium alloy of claim 58, wherein in an as-cast condition, the alloy has a tensile
strength of at least about 155,000 psi.
65. The titanium alloy of claim 58, wherein in an as-cast condition, the alloy has a percent
elongation of at least about 5.0 percent.
66. An titanium alloy, comprising:
aluminum, in a range of about 3.5 to about 6.25 percent by weight of the alloy;
vanadium, in a range of about 3.0 to about 4.5 percent by weight of the alloy;
iron, in a range of up to about 1.0 percent by weight;
chromium, in a range of up to about 3.8 percent by weight of the alloy;
manganese, in a range of about 0.75 to about 2.0 percent by weight of the alloy; and
oxygen, in an range of up to about 0.3 percent by weight of the alloy; and
titanium, being present in a remaining amount;
wherein the combined amount of manganese, chromium and iron is in a range of about
1.0 to about 5.0 percent by weight of the alloy.
67. The titanium alloy of claim 66, wherein the amount of chromium is in a range of about
1.0 to about 2.5 percent by weight of the alloy.
68. The titanium alloy of claim 66 further comprising a pre-existing titanium material.
69. The titanium alloy of claim 68, wherein the pre-existing titanium material is a recycled
titanium material.
70. The titanium alloy of claim 66, wherein the combined amount of manganese, chromium
and iron is in a range of about 2.0 to about 3.5 percent by weight of the alloy.
71. The titanium alloy of claim 66, wherein in an as-cast condition, the alloy has a yield
strength of at least about 135,000 psi.
72. The titanium alloy of claim 66, wherein in an as-cast condition, the alloy has a tensile
strength of at least about 155,000 psi.
73. The titanium alloy of claim 66, wherein in an as-cast condition, the alloy has a percent
elongation of at least about 5.0 percent.
74. A titanium alloy, comprising:
aluminum, in a range of about 3.5 to about 6.25 percent by weight of the alloy;
vanadium, in a range of about 3.0 to about 4.5 percent by weight of the alloy;
chromium, in a range of up to about 3.8 percent by weight of the alloy;
manganese, in a range of up to about 2.0 percent by weight of the alloy;
iron, in a range of up to about 1.0 percent by weight of the alloy;
oxygen, in a range of more than about 0.2 percent to about 0.3 percent by weight of
the alloy; and
titanium present in a remaining amount;
wherein, the combined amount of chromium, manganese and iron is in a range of about
2.0 to about 3.5 percent by weight of the alloy.
75. The alloy of claim 74, wherein the amount of aluminum is in a range of about 5.0 to
about 6.0 percent by weight of the alloy.
76. The alloy of claim 74, wherein the amount of vanadium is in a range of about 3.3 to
about 4.5 percent by weight of the alloy.
77. The alloy of claim 74, wherein the amount of manganese is in a range of up to about
1.5 percent by weight of the alloy.
78. The alloy of claim 74, wherein the amount of manganese is in a range of about 0.75
to about 1.25 percent by weight of the alloy.
79. The alloy of claim 74, wherein the amount of chromium is in a range of about 1.0 to
about 2.5 percent by weight of the alloy.
80. The alloy of claim 74, wherein in an as-cast condition, the alloy has a yield strength
of at least about 135,000 psi.
81. The alloy of claim 74, wherein in an as-cast condition, the alloy has a percent elongation
of at least about 5.0 percent by weight.
82. The alloy of claim 74, wherein in an as-cast condition, the alloy has a tensile strength
of at least about 155,000 psi.
83. The alloy of claim 74, further comprising nitrogen in a range of up to about 0.05
percent by weight of the alloy.
84. The alloy of claim 83, further comprising carbon in a range of up to about 0.1 percent
by weight.
85. The alloy of claim 84, further comprising other elements, wherein each said other
element is present in a range of up to about 0.1 percent by weight of the alloy and
the combined amount of said other elements is in a range of up to about 0.4 percent
by weight of the alloy.
86. A method of making a titanium alloy, comprising:
providing a titanium material;
combining the titanium material with manganese, such that the amount of manganese
in the alloy is in a range of about 0.75 to about 1.25 percent by weight of the alloy,
chromium, such that the amount of chromium in the alloy is in a range of up to about
3.8 percent by weight of the alloy, and iron, such that the amount of iron in the
alloy is in a range of up to about 1.0 percent by weight of the alloy;
wherein the combined amount of chromium, manganese, and iron in the alloy is in a
range of about 1.0 to about 5.0 percent by weight of the alloy.
87. The method of claim 86, wherein the titanium material comprises aluminum in a range
of about 3.5 to about 6.25 percent by weight of the alloy.
88. The method of claim 86, wherein the titanium material comprises vanadium in a range
of about 3.0 to about 4.5 percent by weight of the alloy.
89. The method of claim 86, wherein the titanium material comprises commercially pure
titanium.
90. The method of claim 89, further comprising the step of combining aluminum with the
titanium material, wherein the amount of aluminum in the alloy is in a range of about
3.5 to about 6.25 percent by weight of the alloy.
91. The method of claim 89, further comprising the step of combining vanadium with the
titanium material, wherein the amount of vanadium in the alloy is in a range of about
3.0 to about 4.5 percent by weight of the alloy.