JP2002332531A - Titanium alloy and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide titanium alloy having a low Young's modulus, high strength and high elastic deformability. SOLUTION: The titanium alloy contains at least a group Va (vanadium family) element and titanium(Ti) as a principal component. Further, this alloy exhibits the characteristic that, within the elastic deformation region where the stress to be applied ranges from 0 to the tensile elastic limit strength defined as the stress when permanent deformation truly reaches 0.2% at the tensile test, the slope of a tangent on a stress-strain diagram obtained by the tensile test is decreased with the increase in stress.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a titanium alloy and a method for producing the same. More specifically, the present invention relates to a titanium alloy having a low Young's modulus, a high elastic deformability and a high strength, which can be used for various products, and a method for producing the same.

[0002]

2. Description of the Related Art Titanium alloys have been used in the fields of aviation, military, space, deep sea exploration, etc. because of their excellent specific strength. Also in the automotive field, titanium alloys are used for racing engine valve retainers, connecting rods, and the like. Also, titanium alloys are often used in a corrosive environment because of their excellent corrosion resistance. For example, it is used for materials such as chemical plants and marine buildings, and also for front bumper lowers and rear bumper lowers of automobiles for the purpose of preventing corrosion by a deicing agent. Furthermore, attention has been paid to their lightness (specific strength) and allergy resistance (corrosion resistance), and titanium alloys have been used for accessories such as watches. As described above, titanium alloys are used in various fields, and as a representative titanium alloy,
For example, Ti-5Al-2.5Sn (α alloy), Ti-
6Al-4V (α-β alloy), Ti-13V-11Cr
-3Al (β alloy).

[0003] Conventional titanium alloys have often been used mainly because of their excellent specific strength and corrosion resistance. Recently, however, the low Young's modulus of titanium alloys (eg, β alloys) has been attracting attention. Often used. For example, titanium alloys having a low Young's modulus are used for biocompatible articles (for example, artificial bones and the like), accessories (for example, frames for glasses), sports equipment (for example, golf clubs), springs, and the like. Explaining with a specific example, when a titanium alloy having a low Young's modulus is used for an artificial bone, the Young's modulus approaches the Young's modulus of human bone (about 30 GPa),
The artificial bone has excellent biocompatibility in addition to specific strength and corrosion resistance. In addition, the eyeglass frame made of a titanium alloy with a low Young's modulus fits the body flexibly without giving a feeling of oppression, and is also excellent in shock absorption. It is also said that the use of a titanium alloy having a low Young's modulus for a shaft or a head of a golf club results in a compliant shaft or a head having a low natural frequency, thereby increasing the flight distance of a golf ball. If a spring made of a titanium alloy having a low Young's modulus, a high elastic deformability and a high strength can be obtained, a low spring constant can be achieved without increasing the number of turns and the like, and the weight and size can be reduced.

[0004] Under these circumstances, the present inventor has conceived of developing a titanium alloy having a low Young's modulus, a high elastic deformability, and a high strength exceeding the conventional level, which can be further expanded in various fields. Was. Then, first, when the prior art relating to a titanium alloy having a low Young's modulus was investigated, the following gazette was found.

JP-A-10-219375 discloses that Nb and Ta are combined in a total amount of 20 to 60% by weight.
A titanium alloy is disclosed. Specifically, first,
The raw material is melted to have the composition, and a button ingot is cast. Next, cold-roll the button ingot,
Solution treatment and aging treatment are performed. With this, 75 GPa
A titanium alloy having the following low Young's modulus has been obtained. However, as can be seen from the examples disclosed in this publication, the tensile strength is lowered along with the low Young's modulus, and a titanium alloy having a low Young's modulus, a high elastic deformability and a high strength has not been obtained. Further, there is no disclosure about cold workability required for forming a titanium alloy into a product.

JP-A-2-163334 discloses that "Nb: 10 to 40% by weight, V: 1 to 1%".
0% by weight, Al: 2 to 8% by weight, Fe, Cr, Mn: 1% by weight or less, Zr: 3% by weight or less, O: 0.05 to 0%
0.3% by weight, with the balance being Ti, which is excellent in cold workability ". Specifically, a titanium alloy having excellent cold workability is obtained by subjecting the raw material having the composition to plasma melting, vacuum arc melting, hot forging, and solution treatment. However, there is no description in the gazette about its Young's modulus, elastic deformability and tensile strength. Further, according to the titanium alloy, ln (h ₀ / h) _: 1.3 as the maximum deformation rate at which no compression crack occurs.
Although it is said that 5 to 1.45 is obtained, it is only about 50% at most when converted to a cold working ratio described later.

[0007] Japanese Patent Application Laid-Open No. Hei 8-299428 discloses that 20 to 40% by weight of Nb and 4.5 to 25% are used.
Disclosed is a medical device formed of a titanium alloy having a Young's modulus of 65 GPa or less, comprising Ta by weight, 2.5 to 13% by weight Zr, and the balance substantially Ti.

JP-A-6-73475, JP-A-6-73475
No. 233811 and Japanese Patent Publication No. 10-501719
In these publications, a titanium alloy having a low Young's modulus and a high strength is disclosed.
Only -13Zr is disclosed. Moreover, there is no disclosure regarding the elastic limit strength or elastic deformability.
In the claims, Nb is 35 to 50% by weight, but no specific example corresponding thereto is disclosed.

Japanese Patent Application Laid-Open No. 61-157652 discloses a metal decorative article containing 40 to 60% by weight of Ti and the balance substantially consisting of Nb. Specifically, a metal decorative article is obtained by arc-melting a Ti-45Nb composition raw material, casting, forging and rolling, and subjecting the obtained Nb alloy to cold deep drawing. However, that publication does not describe any specific cold workability. There is no description about the Young's modulus or tensile strength of the Nb alloy.

[0010] Japanese Patent Application Laid-Open No. 6-240390 describes that "containing 10% to less than 25% by weight of vanadium and having an oxygen content of 0.25% by weight or less,
A golf driver head material comprising the remainder of titanium and inevitable impurities "is disclosed. However, the Young's modulus of the alloy used is only about 80 to 90 GPa.

Japanese Patent Application Laid-Open No. 5-111554 discloses a golf club head manufactured by a lost wax precision casting method of a Ni-Ti alloy having superelasticity. This publication states that Nb, V, etc. may be added to some extent, but does not disclose any specific composition thereof, and furthermore, Young's modulus, elastic deformability and tensile strength. Is not disclosed at all.

For reference, the Young's modulus of a conventional titanium alloy is to be added. The α alloy is about 115 GPa, the α + β alloy (for example, Ti-6Al-4V alloy) is about 110 GPa, and the β alloy ( For example, Ti
The solution treatment material of -15V-3Cr-3Al-3Sn) is about 80 GPa, and about 110 GPa after aging treatment. Further, as a result of a test and investigation by the present inventors, the nickel-titanium alloy of the above publication had a Young's modulus of about 90 GPa.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances. That is, as described above, it is an object of the present invention to provide a titanium alloy having a low Young's modulus, a high elastic deformability, and a high strength exceeding the conventional level, which can be further expanded in various fields. It is another object of the present invention to provide a titanium alloy having a low Young's modulus, a high elastic deformation capability, and a high strength, which is easily formed into various products and has excellent cold workability. It is another object of the present invention to provide a production method suitable for producing such a titanium alloy.

[0014]

Means for Solving the Problems The inventor of the present invention has conducted intensive studies and solved various systematic experiments in order to solve this problem.
This has led to the development of a high-strength titanium alloy having a low Young's modulus, a high elastic deformation capability and a high strength, which comprises a group a element and titanium. (1) That is, the titanium alloy of the present invention has at least V
group a (vanadium group) element and titanium (T
i) wherein the applied stress is in the range of elastic deformation from 0 to the tensile elastic limit defined as the stress when the permanent set reaches 0.2% in the tensile test. It is characterized in that the inclination of the tangent line on the stress-strain diagram obtained by the test decreases with increasing stress. By combining titanium with an appropriate amount of Va group element,
A titanium alloy having a low Young's modulus, a high elastic deformation capacity and a high strength is obtained as never before. And the titanium alloy of the present invention can be widely used for various products, and it is possible to improve their functionality and expand the degree of design freedom. Here, for example, it is preferable that the group Va element be 30 to 60% by mass. If it is less than 30% by mass, a sufficient decrease in average Young's modulus cannot be achieved, while if it exceeds 60% by mass, sufficient elastic deformability and tensile strength cannot be obtained, and the density of the titanium alloy increases, resulting in a decrease in specific strength. This is because On the other hand, when the content exceeds 60% by mass, segregation of the material is liable to occur, and the homogeneity of the material is impaired.

The present inventors have also confirmed that this titanium alloy has excellent cold workability. It is not yet clear why the titanium alloy having the composition has a low Young's modulus, a high elastic deformability, a high strength, and excellent cold workability. However, based on the hard researches conducted by the present inventors so far, those characteristics can be considered as follows. In other words, as a result of the present inventor's investigation of one sample relating to the titanium alloy of the present invention, even if this titanium alloy was subjected to cold working, dislocations were hardly introduced, and the (110) plane was extremely in some directions. It was clarified that the structure exhibited a strongly oriented texture. Moreover, in the dark field image using the 111 diffraction points observed with a TEM (transmission electron microscope), it was observed that the contrast of the image moved with the inclination of the sample. This has been observed (111)
This suggests that the surface is curved, which was also confirmed by direct observation of the lattice image at high magnification. Moreover, the radius of curvature of the curvature of the (111) plane was as small as about 500 to 600 nm. This means that the titanium alloy of the present invention has a property that is not known at all with conventional metal materials, in that the effect of processing is reduced by the curvature of the crystal plane rather than the introduction of dislocation.
Further, dislocations were observed in a very small part in a state where the 110 diffraction point was strongly excited, but were hardly observed when the excitation at the 110 diffraction point was eliminated. This indicates that the displacement component around the dislocation is remarkably biased in the <110> direction, suggesting that the titanium alloy of the present invention has a very strong elastic anisotropy. Although the reason is not clear, this elastic anisotropy is also closely related to the excellent cold workability, low Young's modulus, high elastic deformability, and high strength of the titanium alloy according to the present invention. it is conceivable that.

The group Va element may be one or more of vanadium, niobium and tantalum. Each of these elements is a β-phase stabilizing element, but does not necessarily mean that the titanium alloy of the present invention is a conventional β alloy. Although heat treatment is not always necessary, it is possible to achieve higher strength by performing heat treatment.

The titanium alloy of the present invention preferably has a tensile elastic limit strength of 700 MPa or more. This tensile elastic limit strength is, in order, 750 MPa or more, 800 MPa or more,
It is more preferable that the pressure be 850 MPa or more and 900 MPa or more. "Tensile elastic limit strength" refers to the stress applied when the permanent elongation (strain) reaches 0.2% in a tensile test in which loading and unloading of a test piece are gradually repeated. Say In other words, the tensile elastic limit strength is defined as the stress when the permanent set reaches 0.2% in the tensile test. Further, it is preferable that the average Young's modulus is 75 GPa or less. The average Young's modulus is, in order, 70 GPa or less, 65 GPa or less, 60 GPa or less, and 55 GPa.
It is more preferable to be as follows.

The "average Young's modulus" does not mean the "average" of the Young's modulus in a strict sense, but means the Young's modulus representative of the titanium alloy of the present invention. Specifically, in the stress (load) -strain (elongation) diagram obtained by the tensile test, the slope (tangent slope) of the curve at the stress position corresponding to に of the tensile elastic limit strength is averaged. The Young's modulus was used. Therefore, the average Young's modulus is representative of the Young's modulus obtained from the slope of the tangent line on the stress-strain diagram obtained by the tensile test, and is 1% of the tensile elastic limit strength.
/ 2 is defined as the slope of the tangent at the stress position corresponding to / 2. The combination of the high tensile elastic limit strength, the low average Young's modulus, and the above-described unique stress-strain relationship enables the titanium alloy of the present invention to exhibit excellent high elastic deformability.

Incidentally, the "tensile strength" is a stress obtained by dividing the load immediately before the final fracture of the test piece by the cross-sectional area of the parallel portion of the test piece before the test in the tensile test. The term “high elastic deformation capability” as used in the present application means that the elongation of the test piece within the tensile elastic limit strength is large. In addition, the “low Young's modulus” in the present application means that the average Young's modulus is smaller than a conventional general Young's modulus. Further, “high strength” in the present application means that the tensile elastic limit strength or the tensile strength is large.

The "titanium alloy" referred to in the present invention includes various forms, and includes materials (for example, ingots, slabs, billets, sintered bodies, rolled products, forged products, wires, plates,
It is not limited to a bar or the like, but also means a titanium alloy member (eg, an intermediate processed product, a final product, a part thereof, etc.) obtained by processing the same (the same applies hereinafter).

(2) The titanium alloy of the present invention is preferably a sintered alloy. The present invention uses titanium and an appropriate amount of V
It is based on the discovery that a sintered alloy (sintered titanium alloy) comprising a group a element has the mechanical properties of low Young's modulus, high elastic deformability and high strength. The present inventors have also confirmed that this titanium alloy has excellent cold workability. As described above, the content of the Va group element is preferably 30 to 60% by mass. It is not yet clear why the titanium alloy of the composition has high strength with low Young's modulus, high elastic deformability, and excellent cold workability, but at present, the reason is considered as described above.

(3) The method for producing a titanium alloy of the present invention comprises:
A mixing step of mixing at least two or more raw material powders containing titanium and a Va group element, a forming step of forming the mixed powder obtained by the mixing step into a molded body having a predetermined shape, and a forming step obtained by the forming step. Sintering step of heating and sintering the formed body. The obtained sintered alloy has a stress applied from 0 to a stress when the permanent set reaches 0.2% in a tensile test. Within the elastic deformation range in the range up to the defined tensile elastic limit strength, the characteristic that the slope of the tangent on the stress-strain diagram obtained by the tensile test shows a characteristic that decreases with an increase in stress. I do.

The production method of the present invention (hereinafter referred to as “sintering method” as appropriate) is suitable for producing the above-mentioned titanium alloy. As can be understood from the above-mentioned patent publications and the like, a conventional titanium alloy is produced by melting a titanium raw material (for example, titanium sponge) and an alloy raw material, casting the resultant, and then rolling the obtained ingot. (The following,
This method is appropriately referred to as “dissolution method”. ). But,
Since titanium has a high melting point and is very active at high temperatures, dissolution itself is difficult, and a special apparatus is often required for dissolution. Also, it is difficult to control the composition during dissolution, and it is necessary to perform multiple dissolution and the like. Furthermore, as in the titanium alloy of the present invention, a titanium alloy containing a large amount of an alloy component (particularly, a β-stabilizing element) is difficult to avoid macroscopic segregation of the component at the time of melting and casting, so that a titanium alloy of stable quality is obtained. It is difficult to get.

On the other hand, according to the sintering method of the present invention, there is no need to dissolve the raw materials, so there is no disadvantage such as the melting method, and the titanium alloy according to the present invention can be efficiently produced. Specifically, the raw material powder is uniformly mixed in the mixing step, so that a macroscopically uniform titanium alloy can be easily obtained. In addition, since a molded body having a desired shape is molded from the beginning by the molding step, the number of subsequent processing steps can be reduced. The molded body may be in the form of a material such as a plate or a bar, may be in the form of a final product, or may be in the form of an intermediate product before reaching them. And in the sintering process, the compact can be sintered at a temperature much lower than the melting point of the titanium alloy, no special equipment such as a melting method is required, and economical and efficient production is achieved. It becomes possible. The production method of the present invention uses two or more raw material powders in consideration of the mixing step, and is based on a so-called elementary powder (mixing) method.

(4) The method for producing a titanium alloy of the present invention comprises:
A filling step of filling a raw material powder containing titanium and at least a Va group element into a container having a predetermined shape, and after the filling step, sintering the raw material powder in the container by using a hot isostatic method (HIP method). The obtained sintered alloy has a range from 0 applied stress to a tensile elastic limit strength defined as a stress when a permanent set reaches 0.2% in a tensile test. Within the elastic deformation range, the inclination of the tangent line on the stress-strain diagram obtained by the tensile test shows a characteristic of decreasing with an increase in stress.

According to the production method of the present invention, the above-mentioned mixing step and / or molding step are not necessarily required. Further, according to the manufacturing method of the present invention, a so-called alloy powder method is made possible. For this reason, the types of raw material powders that can be used are also widened, and not only a mixed powder obtained by mixing two or more kinds of pure metal powders or alloy powders, but also an alloy powder having the above-described or later-described titanium alloy composition of the present invention is used. can do. By using the HIP method, a dense sintered titanium alloy can be obtained, and a net shape can be obtained even if the product shape is complicated. In addition, the composition range of each of the above elements is shown in the form of “x to y mass%”, and this means that the lower limit (x mass%) and the upper limit (y mass%) are also included unless otherwise specified. .

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Titanium Alloy) (1) Average Young's Modulus and Tensile Elastic Limit Strength The average Young's modulus and tensile elastic limit strength of the titanium alloy of the present invention are described in detail below with reference to FIGS. 1A and 1B. I do.
FIG. 1A is a diagram schematically illustrating a stress-elongation (strain) diagram of a titanium alloy according to the present invention, and FIG. 1B is a diagram illustrating a stress-elongation (titanium alloy (Ti-6Al-4V alloy)) of a conventional titanium alloy. FIG. 3 is a diagram schematically showing a (distortion) diagram.

As shown in FIG. 1B, in the conventional metal material, first, the elongation linearly increases in proportion to the increase in the tensile stress (between '-'). Then, the Young's modulus of the conventional metal material is obtained from the inclination of the straight line. In other words, the Young's modulus is a value obtained by dividing the tensile stress (nominal stress) by the strain (nominal strain) proportional thereto. Thus, in the linear region (between '-') where the stress and the elongation (strain) are in a proportional relationship, the deformation is elastic. For example, when the stress is unloaded, the elongation, which is the deformation of the test piece, becomes zero. Return.
However, when a tensile stress is further applied beyond the linear range, the conventional metal material starts to plastically deform, and even when the stress is unloaded, the elongation of the test piece does not return to 0, and a permanent elongation occurs.

Normally, the stress σp at which the permanent elongation becomes 0.2%
Is referred to as 0.2% proof stress (JIS Z 224).
1). The 0.2% proof stress is obtained by a straight line (') obtained by translating a straight line ('-: tangent line at the rising portion) in the elastic deformation region by 0.2% elongation (strain) on the stress-elongation (strain) diagram. It is also the stress at the intersection (position) of the-) and the stress-elongation (strain) curve. In the case of a conventional metal material, it is generally considered that 0.2% proof stress ≒ tensile elastic limit strength based on an empirical rule that “when elongation exceeds about 0.2%, permanent elongation is achieved”. Conversely, within this 0.2% proof stress, the relationship between stress and strain is considered to be generally linear or elastic.

However, the stress-elongation (strain) shown in FIG.
As can be seen from the diagram, such a conventional concept does not apply to the titanium alloy of the present invention. Although the reason is not clear, in the case of the titanium alloy of the present invention, the stress-elongation (strain) diagram does not become a straight line in the elastic deformation region, but becomes an upwardly convex curve ('-). Elongation returns to zero along-'or permanent elongation along-'. Thus, in the titanium alloy of the present invention,
Even in the elastic deformation region ('-), the stress and the elongation (strain) do not have a linear relationship. When the stress increases, the elongation (strain) rapidly increases. The same applies to the case where the load is unloaded. The stress and the elongation (strain) do not have a linear relationship. When the stress decreases, the elongation (strain) rapidly decreases. It is considered that such a feature appears as the high elastic deformation ability of the titanium alloy of the present invention.

In the case of the titanium alloy of the present invention, as can be seen from FIG. 1A, as the stress increases, the inclination of the tangent line on the stress-elongation (strain) diagram decreases. As described above, since the stress and the elongation (strain) do not change linearly in the elastic deformation region, it is not appropriate to define the Young's modulus of the titanium alloy of the present invention by a conventional method. Further, in the case of the titanium alloy of the present invention, since the stress and the elongation (strain) do not change linearly, it is also possible to evaluate 0.2% yield strength (σp ′) ≒ tensile elastic limit strength by the same method as in the past. Not appropriate. That is, with the 0.2% proof stress obtained by the conventional method, the value is significantly smaller than the original tensile elastic limit strength, and it can no longer be considered that 0.2% proof stress ≒ tensile elastic limit strength.

Therefore, returning to the original definition, the tensile elastic limit strength (σe) of the titanium alloy of the present invention is determined as described above (the position in FIG. 1A). As the modulus, the above average Young's modulus was introduced. 1A and 1B, σt is the tensile strength, εe is the elongation (strain) in the tensile elastic limit strength (σe) of the titanium alloy of the present invention, and εp is 0.2% of the conventional metal material. Elongation (strain) in proof stress (σp).

(2) Composition When the titanium alloy of the present invention is 100% by mass as a whole, at least one kind of a metal element group consisting of zirconium (Zr), hafnium (Hf) and scandium (Sc) is used. It is preferable to contain the elements in a total amount of 20% by mass or less. Zirconium and hafnium are effective for lowering the Young's modulus and increasing the strength of a titanium alloy. In addition, since these elements are the same group (IVa) elements as titanium and are all-solid solution-type neutral elements, they do not prevent the reduction of the Young's modulus of the titanium alloy by the Va group elements. Also, scandium is
When dissolved in titanium, it is an effective element that specifically lowers the bonding energy between titanium atoms together with the group Va element and further lowers the Young's modulus (Reference material: Proc.
9th World Conf. on Titaniu
m, (1999), to be published
d).

If the total amount of these elements exceeds 20% by mass, the strength and toughness are reduced due to material segregation and the cost is increased. In order to balance the Young's modulus, strength, toughness, and the like, it is more preferable that the total of these elements be 1% by mass or more, and more preferably 5 to 15% by mass. In addition, these elements have many portions in common with the Va group elements in operation, and therefore can be replaced with a Va group element within a predetermined range. That is, the titanium alloy of the present invention is:
A total of at least one element in the metal element group consisting of zirconium (Zr), hafnium (Hf), and scandium (Sc) of 20% by mass or less, and one or more elements in the metal element group Consists of a Va group (vanadium group) element having a content of 30 to 60% by mass, and the balance substantially consisting of titanium;
Average Young's modulus is 75 GPa or less and tensile elastic limit strength is 70
It is preferable that the pressure be 0 MPa or more.

The titanium alloy of the present invention has a total of 20
Mass% or less of zirconium (Zr) and hafnium (H
f) and one or more elements in a group of metal elements consisting of scandium (Sc) and one or more elements in the group of metal elements, and a total of 30 to 60% by mass of a Va group (a vanadium group). It is preferable that the sintered alloy is composed of an element and substantially titanium. The reason why the total content of zirconium and the like is set to 20% by mass or less is as described above. Similarly, the total of those elements is 1% by mass or more, and furthermore,
More preferably, the content is 5 to 15% by mass.

The titanium alloy of the present invention is made of chromium (Cr)
, Molybdenum (Mo), manganese (Mn), and iron (Fe)
It is preferable to include at least one element in a metal element group consisting of chromium, cobalt (Co), and nickel (Ni). More specifically, when the whole is 100% by mass, the chromium and the molybdenum are each 20% by mass or less, and the manganese, the iron, the cobalt, and the nickel are each 10% by mass or less. If there is, it is preferable.

Chromium and molybdenum are effective elements for improving the strength and hot forgeability of the titanium alloy.
When the hot forgeability is improved, the productivity and yield of the titanium alloy can be improved. Here, chromium and molybdenum are 2
If the content exceeds 0% by mass, material segregation is likely to occur, and it is difficult to obtain a homogeneous material. 1% by mass of those elements
The above range is preferable in improving the strength and the like by solid solution strengthening, and more preferably 3 to 15% by mass.

Manganese, iron, cobalt and nickel are effective elements for improving the strength and hot forgeability of a titanium alloy, like molybdenum and the like. Therefore, molybdenum,
These elements may be contained instead of chromium or the like, or together with molybdenum, chromium, or the like. However, if the content of these elements exceeds 10% by mass, an intermetallic compound is formed with titanium and ductility is reduced, which is not preferable. When the content of these elements is 1% by mass or more, it is preferable to improve the strength and the like by solid solution strengthening.
It is more preferable to set it as mass%.

When the titanium alloy of the present invention is a sintered titanium alloy, it is preferable to add tin to the group of metal elements. That is, the sintered titanium alloy of the present invention is made of chromium (C
r), molybdenum (Mo), manganese (Mn), and iron (F
e), cobalt (Co), nickel (Ni), and tin (S
It is preferable to include at least one element in the metal element group consisting of n). Specifically, when the whole is 100% by mass, the chromium and the molybdenum are each 20%.
It is more preferable that the manganese, the iron, the cobalt, the nickel, and the tin are each 10% by mass or less.

Tin is an α-stabilizing element and is an effective element for improving the strength of a titanium alloy. Therefore, 10% by mass or less of tin may be contained together with an element such as molybdenum. If the tin content exceeds 10% by mass, the ductility of the titanium alloy is reduced, leading to a reduction in workability. When the content of tin is 1% by mass or more, and more preferably, 2 to 8% by mass, it is more preferable to increase the strength while lowering the Young's modulus. Elements such as molybdenum are the same as described above.

The titanium alloy of the present invention preferably contains aluminum (Al). Specifically, the aluminum is 0.3 to 5 when the whole is 100% by mass.
It is more preferable that the content is mass%. Aluminum is an effective element for improving the strength of a titanium alloy. Therefore, 0.3 to 5% by mass of aluminum may be contained instead of or together with molybdenum or iron. If the aluminum content is less than 0.3% by mass, the solid solution strengthening effect is insufficient, and a sufficient improvement in strength cannot be achieved. Also,
If it exceeds 5% by mass, the ductility of the titanium alloy is reduced.
It is more preferable that the content of aluminum is 0.5 to 3% by mass in order to improve the strength stably. Note that it is more preferable to add aluminum together with tin because strength can be improved without lowering the toughness of the titanium alloy.

It is preferable that the titanium alloy of the present invention contains 0.08 to 0.6% by mass of oxygen (O) when the whole is 100% by mass. Further, when the whole is 100% by mass, 0.05 to 1.0% by mass of carbon (C)
Is preferable. Further, when the whole is set to 100% by mass, it is preferable that 0.05 to 0.8% by mass of nitrogen (N) is contained. In summary, assuming that the whole is 100% by mass, 0.08 to 0.6% by mass of oxygen (O) and 0.1% by mass.
It is preferable to include one or more elements in an element group consisting of 0.05 to 1.0% by mass of carbon (C) and 0.05 to 0.8% by mass of nitrogen (N).

Oxygen, carbon and nitrogen are all interstitial solid solution strengthening elements, stabilizing the α phase of the titanium alloy,
It is an effective element for improving the strength. Oxygen is 0.0
If the content is less than 8% by mass and the content of carbon or nitrogen is less than 0.05% by mass, the strength of the titanium alloy is not sufficiently improved. On the other hand, when the content of oxygen exceeds 0.6% by mass, the content of carbon exceeds 1.0% by mass, or the content of nitrogen exceeds 0.8% by mass, the titanium alloy is embrittled, which is not preferable. When the oxygen content is 0.1% by mass or more, and more preferably 0.15 to 0.45% by mass, the balance between the strength and ductility of the titanium alloy is more preferable. Similarly, 0.1 to 0.8% by mass of carbon and 0.1 to 0.1% by mass of nitrogen.
When the content is 6% by mass, the balance between the strength and the ductility is more preferable.

It is preferable that the titanium alloy of the present invention contains 0.01 to 1.0% by mass of boron (B) when the whole is 100% by mass. Boron is an element effective in improving the mechanical material properties and hot workability of a titanium alloy. Boron hardly dissolves in titanium alloy,
Almost all of them precipitate as titanium compound particles (TiB particles and the like). This is because these precipitated particles significantly suppress the crystal grain growth of the titanium alloy and maintain the structure of the titanium alloy finely. If the amount of boron is less than 0.01% by mass, the effect is not sufficient, and if the amount exceeds 1.0% by mass, precipitation of high-rigidity particles increases, thereby increasing the overall Young's modulus and cold working of the titanium alloy. This is because the property is lowered.

When 0.01% by mass of boron is added, it is 0.055% by volume in terms of TiB particles. On the other hand, when 1% by mass of boron is added, TiB is added.
It is 5.5% by volume in terms of particles. Therefore, in other words, in the titanium alloy of the present invention, it is preferable that the titanium boride particles be in the range of 0.055% by volume to 5.5% by volume. Incidentally, the above-described respective composition elements can be arbitrarily combined within a predetermined range. Specifically, Zr, Hf, Sc, Cr, Mo, Mn, Fe, Co, N
i, Sn, Al, O, C, N, and B may be appropriately and selectively combined within the above range to form the titanium alloy of the present invention. However, this does not preclude the addition of another element within a range that does not depart from the gist of the titanium alloy of the present invention.

(2) Cold Worked Structure The cold worked structure is a structure obtained when a titanium alloy is cold worked. The present inventor has discovered that the above-mentioned titanium alloy is extremely excellent in cold workability, and that the titanium alloy subjected to cold work has a remarkably low Young's modulus, high elastic deformability, and high strength. . The term "cold" means that the temperature is sufficiently lower than the recrystallization temperature of the titanium alloy (the lowest temperature at which recrystallization occurs). Although the recrystallization temperature varies depending on the composition, it is generally about 600 ° C., and the titanium alloy of the present invention is usually preferably cold-worked in a range from room temperature to 300 ° C.

The cold worked structure of X% or more refers to a cold worked structure formed when the cold working ratio defined by the following formula is X% or more. Cold working ratio X = (S ₀ −S) / S ₀ × 100 (%) (S ₀ : cross-sectional area before cold working, S: cross-sectional area after cold working) Titanium alloy Processing strain is imparted inside. It is considered that the processing strain causes a microstructural change at the atomic level in the constituent structure, and contributes to the reduction of the Young's modulus of the titanium alloy of the present invention. In addition, it is considered that the accumulation of elastic strain accompanying the microstructural change at the atomic level due to the cold working contributes to the improvement of the strength of the titanium alloy.

Specifically, it is preferable that the material has a cold worked structure of 10% or more, an average Young's modulus of 70 GPa or less, and a tensile elastic limit strength of 750 MPa or more. By imparting the cold working, it is possible to further reduce the Young's modulus, increase the elastic deformation capability, and increase the strength of the titanium alloy. Further, it is preferable that the titanium alloy of the present invention has the cold-worked structure of 50% or more, the average Young's modulus is 65 GPa or less, and the tensile elastic limit strength is 800 MPa or more. More preferably, the titanium alloy of the present invention has the cold-worked structure of 70% or more, the average Young's modulus is 60 GPa or less, and the tensile elastic limit strength is 850 MPa or more. Furthermore, it is particularly preferable that the titanium alloy of the present invention has the cold-worked structure of 90% or more, an average Young's modulus of 55 GPa or less, and a tensile elastic limit strength of 900 MPa or more.

The titanium alloy of the present invention has a cold working rate of 99
% Or more, and although the details are not clear,
It is distinctly different from conventional titanium alloys. Conventional titanium alloys having excellent cold workability (for example, Ti-22
V-4Al: so-called DAT51), the cold working rate of the titanium alloy according to the present invention is just a surprising value. As described above, the titanium alloy of the present invention is extremely excellent in cold workability, and since the material properties and mechanical properties of the titanium alloy tend to be further improved by the cold work, a high elastic deformability and a low Young's modulus are obtained. It is the most suitable material for various cold-worked products requiring high strength.

(3) Sintered Alloy (Sintered Titanium Alloy) A sintered alloy is an alloy obtained by sintering raw material powder. When the titanium alloy of the present invention is a sintered titanium alloy,
Demonstrates low Young's modulus, high elastic deformability, high strength and excellent cold workability. For example, the sintered titanium alloy has an average Young's modulus of 75 GPa or less and a tensile elastic limit strength of 700M.
Pa or more. Furthermore, the sintered titanium alloy of the present invention adjusts the amount of vacancies in its structure, and has a Young's modulus, strength,
Density and the like can be adjusted. For example, it is preferable that the sintered alloy contains 30% by volume or less of pores. This is because, by setting the porosity to 30% by volume or less, the average Young's modulus can be significantly reduced even with the same alloy composition.

On the other hand, if the sintered alloy has a structure in which the pores are densified to 5% by volume or less by hot working, new features are imparted, which is preferable. That is, when the sintered alloy is densified by hot working, the titanium alloy can have excellent cold workability in addition to low Young's modulus, high elastic deformation capability, and high strength. It is more preferable to reduce the number of pores to 1% by volume or less. The hot working means plastic working at a recrystallization temperature or higher, and includes, for example, hot forging, hot rolling, hot swaging, and HIP.

The pores mean voids remaining in the sintered alloy, and are evaluated by relative density. The relative density is expressed as a percentage (ρ / ρ ₀ ) × 100 (%) of a value obtained by dividing the density ρ of the sintered body by the true density ρ ₀ (in the case of 0% of residual vacancies), Is represented by the following equation. Pore volume% = {1- (ρ / ρ 0)} x100 (%) For example, to CIP molding a metal powder (cold isostatic pressing), the hydrostatic pressure (e.g., 2~4ton / cm2) By adjusting the volume, the volume of the holes can be easily adjusted. Although the size of the pores is not particularly limited, for example, if the average diameter is 50 μm or less, the uniformity of the sintered alloy is maintained, the strength reduction is suppressed, and the titanium alloy has an appropriate size. It is ductile. Here, the average diameter means an average diameter of the circle calculated by replacing the holes measured by the two-dimensional image processing with a circle having an equivalent sectional area.

(Method of Producing Titanium Alloy) (1) Raw Material Powder The raw material powder required for the sintering method contains at least titanium and a Va group element. However, they can take a wide variety of forms. For example, the raw material powder further contains Zr, Hf, Sc, Cr, Mo, Mn, Fe, C
o, Ni, Sn, Al, O, C, N, and B may be included. Specifically, for example, when the total amount of the raw material powder is 100% by mass, one or more elements in a metal element group composed of zirconium (Zr), hafnium (Hf), and scandium (Sc) are combined. Is preferably 20% by mass or less.

The production method of the present invention comprises the steps of:
Total of at least one element in the metal element group consisting of zirconium (Zr), hafnium (Hf), and scandium (Sc) in a total amount of 20% by mass or less, and one or more elements in the metal element group Of mixing at least two or more types of raw material powders containing a Va group (vanadium group) element having a content of 30 to 60% by mass, and forming the mixed powder obtained by the mixing step into a molded body having a predetermined shape. It is preferable that the method comprises a forming step and a sintering step of heating and sintering the formed body obtained in the forming step.

Further, the production method of the present invention is characterized in that titanium and one or more elements in a metal element group consisting of zirconium (Zr), hafnium (Hf) and scandium (Sc) of not more than 20% by mass in total. Filling a raw material powder containing at least a Va group (vanadium group) element having a total of 30 to 60 mass% with one or more elements in the metal element group into a container having a predetermined shape; It is preferable that the method further comprises a sintering step of sintering the raw material powder in the container by using a hot isostatic method (HIP method) after the step. Raw material powder,
Further, it is preferable to include at least one element of chromium, manganese, cobalt, nickel, molybdenum, iron, tin, aluminum, oxygen, carbon, nitrogen, and boron.

When the production method of the present invention involves a mixing step, it is preferable that the raw material powder is composed of two or more of pure metal powder and / or alloy powder. As specific powders to be used, for example, sponge powder, hydrodehydrogenated powder, hydrogenated powder, atomized powder and the like can be used. The particle shape and particle size (particle size distribution) of the powder are not particularly limited, and a commercially available powder can be used as it is. However, it is preferable that the powder used has an average particle diameter of 100 μm or less from the viewpoint of cost and the denseness of the sintered body. Further, when the particle size of the powder is 45 μm (# 325) or less, a denser sintered body can be easily obtained.

When the production method of the present invention uses the HIP method, it is preferable that the raw material powder is composed of an alloy powder containing titanium and at least a group Va element. This alloy powder is a powder having the composition of the titanium alloy according to the present invention, and manufactured by, for example, a gas atomizing method, a REP method (rotating electrode method), a PREP method (plasma rotating electrode method), or a melting method. Hydrogenation of the ingot followed by crushing, and also by MA (mechanical alloying)
Manufactured.

(2) Mixing Step The mixing step is a step of mixing raw material powders. For mixing them, a V-type mixer, a ball mill and a vibration mill, a high energy ball mill (for example, an attritor) and the like can be used.

(3) Forming Step The forming step is a step of forming the mixed powder obtained in the mixing step into a molded body having a predetermined shape. The shape of the molded body may be the final shape of the product, or may be a billet shape when further processing is performed after the sintering step. The molding process includes, for example, mold molding, CIP molding (cold isostatic press molding),
RIP molding (rubber isostatic press molding) or the like can be used.

(4) Filling Step The filling step contains titanium and at least a Va group element.
This is a step of filling the above-mentioned raw material powder into a container having a predetermined shape, which is necessary to use a hot isostatic method (HIP method). The inner shape of the container for filling the raw material powder corresponds to a desired product shape. Further, the container may be made of, for example, metal, ceramic, or glass. Further, it is preferable that the raw material powder is filled and sealed in a container by degassing under vacuum.

(5) Sintering Step The sintering step is a step of heating and sintering the molded body obtained in the molding step to obtain a sintered body, or a hot isostatic method (HIP) after the filling step. ) Is to solidify the powder in the container under pressure. When sintering the compact, it is preferable to perform the sintering in a vacuum or an inert gas atmosphere. Further, the sintering temperature is preferably lower than the melting point of the alloy and in a temperature range in which the component elements are sufficiently diffused. For example, the temperature range is 1200 ° C. to 1400 ° C.
It is. Further, the sintering time is preferably 2 to 16 hours. Therefore, in order to achieve the densification of titanium alloy and the improvement of productivity, 1200 ° C. to 1400 ° C. and 2 to 16 ° C.
The sintering step is preferably performed under the condition of time.

In the case of the HIP method, it is preferable that the heat treatment is carried out in a temperature range in which diffusion is easy, powder deformation resistance is small, and reaction with the container is difficult. For example, the temperature range is 900C to 1300C. The molding pressure is
Preferably, the pressure is such that the filling powder can sufficiently creep. For example, the pressure range is 50 to 200 MPa.
(500-2000 atm). The processing time of the HIP is preferably such that the powder is sufficiently creep-deformed and densified, and the alloy component can diffuse between the powders.
The time is 1 hour to 10 hours.

(6) Working Step By performing hot working, the pores and the like of the sintered alloy can be reduced and the structure can be densified. Therefore, the manufacturing method of the present invention preferably further includes a hot working step of hot working the sintered body obtained after the sintering step to densify the structure of the sintered body. This hot working may be performed to form a general product shape.

Since the titanium alloy obtained by the production method of the present invention is excellent in cold workability, various products can be produced by cold working the obtained sintered body. Therefore, it is preferable that the manufacturing method of the present invention further includes a cold working step of cold working the sintered body obtained after the sintering step to form a material or a product. Then, after performing the rough working by the hot working, the finish working may be performed by the cold working.

(Use of Titanium Alloy) The titanium alloy of the present invention has a low Young's modulus, a high elastic deformation capacity, and a high strength, so that it can be widely used for products matching the characteristics. In addition, since the titanium alloy of the present invention is used for a cold-worked product because it has excellent cold workability, work cracks and the like are significantly reduced, and the yield is improved. Also, with conventional titanium alloys,
According to the titanium alloy of the present invention, it is possible to form a product that requires cutting in shape by cold forging or the like, which is very effective for mass production and cost reduction of the titanium product. For example, the titanium alloy of the present invention is used for industrial machinery, automobiles, motorcycles, bicycles, home appliances, aerospace equipment, ships,
It can be used for jewelry, sports and leisure goods, biological related goods, medical equipment, toys, etc.

Taking the (coil) spring of an automobile as an example, the titanium alloy of the present invention has a Young's modulus of 1/3 to 1/5 with respect to a conventional spring steel, and an elastic deformation capacity of 5%.
Since it is twice or more, the number of turns can be reduced from 1/3 to 1/5. Furthermore, since the titanium alloy of the present invention has a specific gravity of only about 70% of steel used for a normal spring, a significant reduction in weight can be realized.

In the case of an eyeglass frame as an accessory, the titanium alloy of the present invention has a lower Young's modulus than a conventional titanium alloy, so that the vine and the like are easily bent, and fit well to the face. Excellent absorption and shape restoration. Furthermore, since it is high in strength and excellent in cold workability, it can be easily formed from a thin wire into an eyeglass frame or the like, and the yield can be improved. In addition, according to the spectacle frame from the thin wire material, the fit, the lightness, and the wearing feeling of the spectacles are further improved.

Further, a golf club will be described as an example of a sports / regular article. For example, when the shaft of a golf club is made of the titanium alloy of the present invention, the shaft is easily bent and the elasticity transmitted to the golf ball is increased. Energy can be increased and the flight distance of the golf ball can be expected to be improved. Further, when the head of the golf club, particularly the face portion, is made of the titanium alloy of the present invention, the natural frequency of the head is significantly reduced as compared with the conventional titanium alloy due to its low Young's modulus and thinning due to high strength. According to the golf club having the head, it is expected that the flight distance of the golf ball can be considerably extended. The theory regarding the golf club is described in, for example, Japanese Patent Publication No. 7-9807.
No. 7 and International Publication WO98 / 46312. In addition, according to the titanium alloy of the present invention,
Due to its excellent characteristics, the feel at impact of the golf club and the like can be improved, and the degree of freedom in designing the golf club can be significantly increased.

In the medical field, artificial bones, artificial joints,
The titanium alloy of the present invention can be used for things to be disposed in a living body such as artificial grafts and bone fasteners, and functional members (catheter, forceps, valves, etc.) of medical instruments. For example, when the artificial bone is made of the titanium alloy of the present invention, the artificial bone has a low Young's modulus close to human bone, is balanced with human bone, is excellent in biocompatibility, and has a sufficiently high strength as bone. .

Further, the titanium alloy of the present invention is suitable for a vibration damping material. E = ρV2 (E: Young's modulus, ρ: Material density,
This is because, as can be seen from the relational expression of (V: sound speed transmitted through the material), the sound speed transmitted through the material can be reduced by lowering the Young's modulus.

In addition, the titanium alloy of the present invention is, for example,
Materials (wires, bars, squares, plates, foils, fibers, fabrics, etc.), mobile goods (watches (watches), Vallettas (hair ornaments),
Necklaces, bracelets, earrings, earrings, rings, tie pins, brooches, cufflinks, belts with buckles, lighters, fountain pen nibs, fountain pen clips, key chains, keys, ballpoint pens, mechanical pencils, etc., mobile information terminals (mobile phones) , Portable recorders, mobile PC cases, etc.), engine valve springs, suspension springs, bumpers, gaskets, diaphragms, bellows, hoses, hose bands, tweezers, fishing rods, fishing hooks, sewing needles, sewing needles,
Injection needles, spikes, metal brushes, chairs, sofas, beds, clutches, bats, various wires, various binders, paper clips, cushioning materials, various metal seals, expanders, trampolines, various health exercise equipment, wheelchairs, nursing equipment , Rehabilitation equipment, brassier, corset, camera body, shutter parts, blackout curtains, curtains, blinds, balloons, airships, tents, various membranes, helmets, fishnets, tea strainers, umbrellas, fire clothes, bulletproof vests, fuel tanks, and other containers It can be used for various products in various fields such as tire linings, tire reinforcements, bicycle chassis, bolts, rulers, various torsion bars, springs, and power transmission belts (such as CVT hoops). And the titanium alloy and the product thereof according to the present invention can be manufactured by various manufacturing methods such as casting, forging, superplastic forming, hot working, cold working, and sintering.

[0072]

EXAMPLES Various specific examples in which the composition, the cold working ratio and the like are changed will be described below, and the titanium alloy according to the present invention and the method for producing the same will be described in more detail. A. Specimens 1 to 84 First, using the method for manufacturing a titanium alloy according to the present invention,
Test materials 1 to 84 were produced.

(1) Specimens 1 to 13 Specimens 1 to 13 relate to a titanium alloy comprising 30 to 60% by mass of a Va group element and titanium. a. Test material 1 Commercially available hydrogenated / dehydrogenated Ti powder (-# 325,-# 10) corresponding to the titanium powder referred to in the present invention as the raw material powder
0), niobium (Nb) powder (-# 325), vanadium (V) powder (-# 325), tantalum (Ta) powder (-
# 325). Hereinafter, the same powder as described above is simply referred to as “titanium powder”, “niobium powder”, “vanadium powder”, “tantalum powder”, or the like. The oxygen content at this time was adjusted with oxygen contained in the titanium powder. Further, the compositions in Table 1 are shown in mass%, and the description of the remaining titanium is omitted. These powders were blended and mixed so as to have the composition ratios shown in Table 1 (mixing step). This mixed powder is subjected to a pressure of 4 ton / cm 2
CIP molding (cold isostatic molding) at φ40x80m
m was obtained (a molding step). The molded body obtained by the molding step was placed at 1.3 × 10 ⁻³ Pa (1 × 10 ^−5).
The resultant was heated and sintered at 1300 ° C. for 16 hours in a vacuum of torr) to obtain a sintered body (sintering step). Further, the sintered body was hot forged in an atmosphere at 700 to 1150 ° C. (hot working step) to obtain a round bar having a diameter of 10 mm.

B. Test Material 2 As raw materials, titanium sponge, high-purity niobium, and vanadium briquette were prepared. These raw materials were blended in an amount of 1 kg so as to have a composition ratio shown in Table 1 (blending step). This raw material was melted using an induction skull (melting step), and after casting in a mold (casting step), a molten material of φ60 × 60 mm was obtained. In addition, for the dissolution, five re-dissolution treatments were performed for homogenization. 700-1150 ° C
Hot forging in the atmosphere of (hot working process), φ10mm
This was used as Test Material 2. c. Test materials 3 and 4 and Test materials 8 to 11 Titanium powder, niobium powder, and tantalum powder were used as raw material powders so as to have the composition ratios shown in Table 1. Thereafter, each test material was manufactured in the same manner as the test material 1.

D. Test material 7 As raw materials, titanium sponge, high-purity niobium, and tantalum briquettes were prepared. These raw materials were blended in an amount of 1 kg so as to have a composition ratio shown in Table 1 (blending step). Thereafter, the test material 7 was manufactured in the same manner as the test material 2. e. Test materials 5, 6, 12, 13 Titanium powder, niobium powder, tantalum powder, and vanadium powder were used as raw material powders so that the composition ratios were as shown in Table 1. Thereafter, each test material was manufactured in the same manner as the test material 1.

(2) Specimens 14 to 24 Specimens 14 to 24 were obtained by replacing some of the Va group elements of Specimens 6 to 10 and 12 with zirconium, hafnium and scandium as shown in Table 2. It was done. a. Specimen 14 Specimen 14 was obtained by substituting a part of tantalum of Specimen 9 with zirconium. The composition ratios shown in Table 2 were obtained using titanium powder, niobium powder, tantalum powder, and zirconium (Zr) powder (-# 325) as raw material powders. After this, the test material 1
4 was produced.

B. Specimen 15 Specimen 15 was obtained by substituting a part of niobium of Specimen 7 with zirconium. As raw materials, titanium sponge,
High purity niobium and tantalum briquettes were prepared. These raw materials were blended in an amount of 1 kg so as to have a composition ratio shown in Table 2 (blending step). Thereafter, the test material 15 was manufactured in the same manner as the test material 2. c. Specimen 16 Specimen 16 was obtained by substituting a part of niobium of Specimen 8 with zirconium. As a raw material powder, a titanium powder and a niobium powder, a tantalum powder, and a zirconium powder were used so that the composition ratio was as shown in Table 2. Thereafter, the test material 16 was manufactured in the same manner as the test material 1.

D. Specimen 17 Specimen 17 was obtained by replacing a part of tantalum of the specimen 10 with zirconium. As a raw material powder, a titanium powder and a niobium powder, a tantalum powder, and a zirconium powder were used so that the composition ratio was as shown in Table 2. From now on,
A test material 17 was produced in the same manner as the test material 1. e. Specimen 18 Specimen 18 was obtained by replacing tantalum in Specimen 10 with zirconium. The composition ratios shown in Table 2 were obtained using titanium powder, niobium powder, and zirconium powder as raw material powders. Thereafter, the test material 18 was manufactured in the same manner as the test material 1.

F. Specimen 19 Specimen 19 was obtained by substituting a part of niobium and tantalum in Specimen 9 with zirconium. As a raw material powder, a titanium powder and a niobium powder, a tantalum powder, and a zirconium powder were used so that the composition ratio was as shown in Table 2. Thereafter, the test material 19 was manufactured in the same manner as the test material 1. g. Specimen 20 Specimen 20 was obtained by substituting a part of niobium and vanadium of the specimen 12 with zirconium. Titanium powder, niobium powder, vanadium powder, tantalum powder, and zirconium powder were used as raw material powders so that the composition ratio was as shown in Table 2. Thereafter, the test material 20 was manufactured in the same manner as the test material 1.

H. Specimen 21 Specimen 21 was obtained by substituting a part of vanadium of Specimen 6 with zirconium and hafnium. The composition ratios shown in Table 2 were obtained using titanium powder, niobium powder, vanadium powder, tantalum powder, zirconium powder, and hafnium (Hf) powder (-# 325) as raw material powders. After that, the test material 21 was prepared in the same manner as the test material 1.
Was manufactured. i. Specimen 22 Specimen 22 is obtained by substituting a part of niobium and tantalum of the specimen 10 with hafnium. As a raw material powder, a titanium powder, a niobium powder, a tantalum powder, and a hafnium powder were used so that the composition ratio was as shown in Table 2. Thereafter, the test material 22 was manufactured in the same manner as the test material 1.

J. Specimen 23 Specimen 23 was obtained by substituting a part of niobium of Specimen 12 with zirconium. Titanium powder, niobium powder, vanadium powder, tantalum powder, and zirconium powder were used as raw material powders so that the composition ratio was as shown in Table 2. Thereafter, the test material 23 was manufactured in the same manner as the test material 1. k. Specimen 24 Specimen 24 was obtained by substituting niobium and tantalum of specimen 9 with a part of scandium. As raw material powders, titanium powder, niobium powder, tantalum powder, scandium (S
c) Using powder (-# 325), the composition ratio was as shown in Table 2. Thereafter, the test material 24 was manufactured in the same manner as the test material 1.

(3) Specimens 25 to 31 Specimens 25 to 31 were specimens 11, 14, 16, 17,
18 and 23 are further blended with chromium, manganese, cobalt, nickel, molybdenum and iron. a. Specimen 25 Specimen 25 is chromium added to Specimen 23. The composition ratios shown in Table 3 were obtained using titanium powder, niobium powder, vanadium powder, tantalum powder, zirconium powder, and chromium (Cr) powder (-# 325) as raw material powders. Thereafter, the test material 25 was manufactured in the same manner as the test material 1. b. Test material 26 The test material 26 is obtained by adding molybdenum to the test material 14. The composition ratios shown in Table 3 were obtained using titanium powder, niobium powder, tantalum powder, zirconium powder, and molybdenum (Mo) powder (-# 325) as raw material powders. Thereafter, the same procedure as for the test material 1 was performed.
6 was produced.

C. Specimen 27 The Specimen 27 is obtained by adding molybdenum to the Specimen 11. The composition ratios shown in Table 3 were obtained using titanium powder, niobium powder, tantalum powder, and molybdenum powder as raw material powders. Thereafter, the test material 27 was manufactured in the same manner as the test material 1. d. Specimen 28 Specimen 28 is obtained by adding cobalt to the specimen 18. The composition ratios shown in Table 3 were obtained using titanium powder, niobium powder, zirconium powder, and cobalt (Co) powder (-# 325) as raw material powders. Thereafter, the test material 28 was manufactured in the same manner as the test material 1.

E. Test Material 29 The test material 29 is obtained by adding nickel to the test material 16. The composition ratios shown in Table 3 were obtained using titanium powder, niobium powder, tantalum powder, zirconium powder, and nickel (Ni) powder (-# 325) as raw material powders. After this, the test material 29 is prepared in the same manner as the test material 1.
Was manufactured. f. Test material 30 The test material 30 is obtained by adding manganese to the test material 17. The composition ratios shown in Table 3 were obtained using titanium powder, niobium powder, tantalum powder, zirconium powder, and manganese (Mo) powder (-# 325) as raw material powders. Thereafter, the test material 30
Was manufactured.

G. Test Material 31 The test material 31 is obtained by adding iron to the test material 14.
As raw material powder, titanium powder, niobium powder, tantalum powder, zirconium powder, iron (Fe) powder (-# 325)
Was used so that the composition ratio was as shown in Table 3. Thereafter, the test material 31 was manufactured in the same manner as the test material 1.

(4) Specimens 32 to 38 Specimens 32 to 34 are obtained by further mixing aluminum with the specimens 14, 16, and 18. Test material 35-3
Reference numeral 8 is a material in which tin (and aluminum) is further added to the test materials 8, 16, and 18. a. Test Material 32 The test material 32 is obtained by adding aluminum to the test material 16. As raw material powder, titanium powder and niobium powder,
Tantalum powder, zirconium powder, aluminum (A
l) Powder (-# 325) was used to make the composition ratio shown in Table 3. Thereafter, the test material 32 was manufactured in the same manner as the test material 1. b. Test material 33 The test material 33 is obtained by adding aluminum to the test material 18. As raw material powder, titanium powder and niobium powder,
Table 3 using zirconium powder and aluminum powder.
Of the composition ratio. Thereafter, the test material 33 was manufactured in the same manner as the test material 1.

C. Test Material 34 The test material 34 is obtained by adding aluminum to the test material 14. As raw material powder, titanium powder and niobium powder,
The composition ratio was as shown in Table 3 using tantalum powder, zirconium powder, and aluminum powder. Thereafter, the test material 34 was manufactured in the same manner as the test material 1. d. Test material 35 The test material 35 is obtained by adding tin to the test material 7. The composition ratios shown in Table 3 were obtained by using titanium powder, niobium powder, tantalum powder, and tin (Sn) powder (-# 325) as raw material powders. Thereafter, the test material 35 was manufactured in the same manner as the test material 1.

E. Test Material 36 The test material 36 is obtained by adding tin to the test material 16.
As a raw material powder, a titanium powder and a niobium powder, a tantalum powder, a zirconium powder, and a tin powder were used so that the composition ratio was as shown in Table 3. Thereafter, the test material 36 was manufactured in the same manner as the test material 1. f. Specimen 37 Specimen 37 is obtained by adding tin to the specimen 18.
Using titanium powder, niobium powder, zirconium powder, and tin powder as raw material powders, the composition ratio was as shown in Table 3. After this, the test material 37 is made in the same manner as the test material 1.
Was manufactured.

G. Test Material 38 The test material 38 is obtained by adding tin and aluminum to the test material 16. The composition ratios shown in Table 3 were obtained using titanium powder, niobium powder, tantalum powder, zirconium powder, tin powder, and aluminum powder as raw material powders. Thereafter, the test material 38 was manufactured in the same manner as the test material 1.

(5) Specimens 39-46 Specimens 39-46 were specimens 4, 10, 14, 17, 1
The amount of oxygen contained in No. 8 was positively changed. a. Specimens 39, 40 Specimens 39, 40 were obtained by increasing the oxygen content of the specimen 4. As raw material powder, titanium powder and niobium powder,
The composition ratio was as shown in Table 4 using tantalum powder. Thereafter, the same as the test material 1, the test material 39,
40 were produced. b. Test materials 41 and 42 The test materials 41 and 42 are obtained by increasing the oxygen content of the test material 10. Using titanium powder, niobium powder, and tantalum powder as the raw material powder, the composition ratio was as shown in Table 4. After this, the test material 4
1, 42 were produced.

C. Test Materials 43 and 44 The test materials 43 and 44 are obtained by increasing the oxygen content of the test material 14. Using titanium powder, niobium powder, tantalum powder, and zirconium powder as raw material powders, Table 4
Of the composition ratio. Thereafter, the test materials 43 and 44 were manufactured in the same manner as the test material 1. d. Test material 45 The test material 45 is obtained by increasing the oxygen content of the test material 18. Using titanium powder, niobium powder, and zirconium powder as the raw material powder, the composition ratio was as shown in Table 4. Thereafter, the test material 45 was manufactured in the same manner as the test material 1.

E. Test Material 46 The test material 46 is obtained by increasing the oxygen content of the test material 17. Using titanium powder, niobium powder, tantalum powder, and zirconium powder as the raw material powder, the composition ratio was as shown in Table 4. Thereafter, the test material 46 was manufactured in the same manner as the test material 1.

(6) Specimens 47 to 54 Specimens 47 to 54 were obtained by further adding carbon, nitrogen and boron to the specimens 10, 16, 17, and 18. a. Specimens 47 and 48 Specimens 47 and 48 were obtained by adding carbon to the specimen 18. Using titanium powder and niobium powder, zirconium powder and TiC powder (-# 325) as raw material powders,
The composition ratio was as shown in Table 4. Thereafter, the test materials 47 and 48 were manufactured in the same manner as the test material 1. b. Test material 49 Test material 49 is obtained by adding carbon to the test material 16. Using titanium powder and niobium powder, tantalum powder, zirconium powder and TiC powder as raw material powders, Table 4
The composition ratio of Thereafter, the test material 49 was manufactured in the same manner as the test material 1.

C. Specimens 50 and 51 Specimens 50 and 51 were obtained by adding nitrogen to the specimen 17. As raw material powders, titanium powder and niobium powder, tantalum powder, zirconium powder and TiN powder (-# 32
Using 5), the composition ratio was as shown in Table 4. Thereafter, the test materials 50 and 51 were manufactured in the same manner as the test material 1. d. Test material 52 The test material 52 is obtained by adding boron to the test material 17. As raw material powders, titanium powder and niobium powder, tantalum powder, zirconium powder and TiB2 powder (-# 32
Using 5), the composition ratio was as shown in Table 4. Thereafter, the test material 52 was manufactured in the same manner as the test material 1.

E. Test Material 53 The test material 53 is obtained by adding boron to the test material 16. Titanium powder, niobium powder, tantalum powder, zirconium powder, and TiB2 powder were used as raw material powders, and the composition ratio was as shown in Table 4. After this, test material 1
Specimen 53 was manufactured in the same manner as described above. f. Test Material 54 The test material 54 is obtained by adding boron to the test material 10. As a raw material powder, a titanium powder and a niobium powder, and a tantalum powder and a TiB2 powder were used, and the composition ratio was as shown in Table 4. Thereafter, the test material 54 was manufactured in the same manner as the test material 1.

(7) Specimens 55-76 Specimens 55-74 were specimens 2, 7, 14, 15, 1
6, 17, 18, 22, 26, 32, and 53 are further cold-worked. a. Specimen 55 Specimen 55 is obtained by subjecting specimen 2 to cold working. As raw materials, titanium sponge, high-purity niobium, and vanadium briquette were prepared. These materials are listed in Table 5A.
1 kg was blended so that the composition ratio was as follows (blending step).
This raw material was melted using an induction skull (melting step) and cast into a mold (casting step) to obtain a φ60 × 60 molten material. In addition, for the dissolution, five re-dissolution treatments were performed for homogenization. 700-1150 ° C
Hot forging in the atmosphere of (hot working process), φ20mm
Round bar. The φ20 mm round bar was cold-worked by a cold swaging machine to produce a test material 55 having a cold-working rate shown in Table 5A.

B. Test Material 56 The test material 56 is obtained by subjecting the test material 7 to cold working. As raw materials, titanium sponge, high-purity niobium and tantalum briquettes were prepared. These raw materials were blended in an amount of 1 kg so as to have a composition ratio shown in Table 5A (blending step). Thereafter, in the same manner as the test material 55, a test material 56 having a cold working rate shown in Table 5A was manufactured. c. Specimens 57 and 58 Specimens 57 and 58 were obtained by subjecting the specimen 15 to cold working. As raw materials, titanium sponge, high-purity niobium, tantalum, and zirconium briquettes were prepared.
These raw materials were blended in an amount of 1 kg so as to have a composition ratio shown in Table 5A (blending step). Thereafter, similarly to the test material 55, the test materials 57 and 58 having the cold working rates shown in Table 5A are used.
Was manufactured.

D. Specimens 59 to 62 Specimens 59 to 62 were obtained by subjecting the specimen 14 to cold working. As raw material powder, titanium powder and niobium powder,
Using tantalum powder and zirconium powder, they were blended and mixed so as to have the composition ratio shown in Table 5A (mixing step). This mixed powder was subjected to CIP molding (cold isostatic pressing) at a pressure of 4 ton / cm 2 to obtain a cylindrical molded body of φ40 × 80 mm (molding step). 1.3 × 10 ⁻³ Pa (1 × 10 ⁻⁵ torr) of the molded body obtained by the molding step
Then, it was heated at 1300 ° C. for 16 hours in a vacuum and sintered to obtain a sintered body (sintering step). Furthermore, this sintered body was
Hot forging was performed in the atmosphere at ~ 1150 ° C (hot working step) to obtain a round bar of φ20 mm. This round bar of φ20 mm was cold-worked by a cold swaging machine to produce test materials 59 to 62 having a cold-working rate shown in Table 5A.

E. Specimens 63 to 66 Specimens 63 to 66 were obtained by subjecting the specimen 16 to cold working. As raw material powder, titanium powder and niobium powder,
Using tantalum powder and zirconium powder, they were blended and mixed so as to have the composition ratio shown in Table 5A (mixing step). Thereafter, in the same manner as the test material 59, a test material having a cold working rate shown in Table 5A was manufactured. f. Specimens 67 to 70 Specimens 67 to 70 were obtained by subjecting the specimen 18 to cold working. As raw material powder, titanium powder and niobium powder,
Using zirconium powder, it was blended and mixed so as to have the composition ratio shown in Table 5A (mixing step). From now on,
A test material having a cold working rate shown in Table 5A was manufactured in the same manner as the test material 59.

G. Specimens 71 to 73 Specimens 71 are obtained by subjecting the specimen 53 to cold working. Using titanium powder, niobium powder, tantalum powder, zirconium powder and TiB2 powder as raw material powders, they were blended and mixed so as to have the composition ratio shown in Table 5B (mixing step). Thereafter, in the same manner as the test material 59,
Specimens having the cold working rates shown in Table 1 were produced. h. Test material 74 The test material 74 is obtained by subjecting the test material 17 to cold working. Using titanium powder, niobium powder, tantalum powder, and zirconium powder as raw material powders, they were blended and mixed so as to have a composition ratio shown in Table 5B (mixing step). Thereafter, in the same manner as the test material 59, a test material 74 having a cold working rate shown in Table 5B was manufactured.

I. Specimen 75 The specimen 75 has been subjected to cold working of the specimen 22. Using titanium powder, niobium powder, tantalum powder, and hafnium powder as raw material powders, they were blended and mixed so as to have a composition ratio shown in Table 5B (mixing step). Thereafter, in the same manner as the test material 59, a test material 75 having a cold working rate shown in Table 5B was manufactured. j. Test Material 76 The test material 76 is obtained by subjecting the test material 26 to cold working. As raw material powder, using titanium powder and niobium powder, tantalum powder, zirconium powder, manganese powder,
The components were blended and mixed so as to have the composition ratio shown in Table 5B (mixing step). Thereafter, the same as in the case of the test material 59,
A test material 76 having a cold working rate shown in B was produced.

K. Test Material 77 The test material 77 is obtained by subjecting the test material 32 to cold working. Using titanium powder, niobium powder, tantalum powder, zirconium powder, and aluminum powder as raw material powders, they were blended and mixed so as to have the composition ratio shown in Table 5B (mixing step). Thereafter, in the same manner as the test material 59,
A test material having a cold working rate shown in Table 5B was manufactured.

(8) Specimens 78 to 81 Specimens 78 to 81 were obtained by increasing the porosity in the sintered body by lowering the molding pressure of the CIP molding than that of each of the aforementioned specimens. It is. a. Test materials 78 and 79 The test materials 78 and 79 have the same composition as the test material 8. Titanium powder, niobium powder, and tantalum powder were prepared as raw material powders. The oxygen content at this time was adjusted with oxygen contained in the titanium powder. These powders were blended and mixed so as to have the composition ratios shown in Table 6 (mixing step). This mixed powder was subjected to a pressure of 3.8 to
n / cm 2, the test material 79 was at a pressure of 3.5 ton / cm 2
CIP molding (cold isostatic molding), φ10x80mm
(Molding step). The molded body obtained by the molding step was placed at 1.3 × 10 ⁻³ Pa (1 × 10 ^−5).
(torr) vacuum at 1300 ° C. for 16 hours for sintering to obtain a sintered body (sintering step).
79. When the porosity at this time was calculated, it was 2% for the test material 78 and 5% for the test material 79.

B. Test Material 80 The test material 80 has the same composition as the test material 18. Titanium powder, niobium powder, and zirconium powder were prepared as raw material powders. These powders were blended and mixed so as to have the composition ratios shown in Table 6 (mixing step).
This mixed powder was subjected to CIP molding (cold isostatic pressing) at a pressure of 3.0 ton / cm 2 to obtain a cylindrical molded body of φ10 × 80 mm (molding step). The molded body obtained by the molding step was heated at 1300 ° C. for 16 hours in a vacuum of 1.3 × 10 ⁻³ Pa (1 × 10 ⁻⁵ torr) to be sintered to obtain a sintered body (sintering step). Material 80. In addition,
The porosity at this time was calculated to be 10%.

C. Test Material 81 The test material 81 has the same composition as the test material 16. Titanium powder, niobium powder, tantalum powder, and zirconium powder were prepared as raw material powders. The oxygen content at this time was adjusted with oxygen contained in the titanium powder.
These powders were blended and mixed so as to have the composition ratios shown in Table 6 (mixing step). This mixed powder is applied under a pressure of 2.5.
CIP molding (cold isostatic molding) at ton / cm2
A cylindrical shaped body of φ10 × 80 mm was obtained (forming step). The molded body obtained by the molding step is 1.3 × 10 ^−3.
1300 ° C x 1 in a vacuum of Pa (1 x 10 ^-5 torr)
It was heated for 6 hours and sintered to form a sintered body (sintering step). The porosity at this time was calculated to be 25%.

(9) Specimens 82 to 84 Specimens 82 to 83 are titanium alloys manufactured by the HIP method. a. Test material 82 A mixed powder prepared by using titanium powder, niobium powder, and tantalum powder as a raw material powder so as to have a composition ratio shown in Table 6 was filled in a pure titanium container. 3Pa
(1 × 10 ⁻² torr) and then sealed (filling step). 1000 ° C x 200M container with mixed powder
It was kept for 2 hours under the condition of Pa and sintered by the HIP method (sintering step). The φ20 × 80 mm thus obtained was used as a test material 82.

B. Test material 83 The φ20 mm round bar obtained as the test material 82 was cold worked by a cold swaging machine to produce a test material 83 having a cold working rate shown in Table 6. did. c. Test material 84 The test material 84 is obtained by subjecting the test material 78 to cold working. Using titanium powder, niobium powder, and tantalum powder as raw material powders, they were blended and mixed to have the composition ratios shown in Table 6 (mixing step). This mixed powder was subjected to a pressure of 3.8.
CIP molding (cold isostatic molding) at ton / cm2
A cylindrical molded body of φ20 × 80 mm was obtained (molding step). The molded body obtained by the molding step is 1.3 × 10 ^−3.
1300 ° C x 1 in a vacuum of Pa (1 x 10 ^-5 torr)
It was heated for 6 hours and sintered to obtain a sintered body (sintering step).
The sintered body having a diameter of 20 mm was cold worked by a cold swaging machine to produce a test material 84 having a cold working rate shown in Table 6.

B. Specimens C1 to C5 and Specimens D1 to D3 Next, a specimen C having a composition that does not belong to the composition range described above or obtained by a method different from the production method described above.
1 to C5 and test materials D1 to D3 were produced. (1) Specimens C1 to C5 a. Specimen C1 relates to a titanium alloy containing less than 30% by mass of a Va group element. Titanium powder and niobium powder were prepared as raw material powders. The oxygen content at this time was adjusted with oxygen contained in the titanium powder. Each of these powders was blended and mixed so as to have a composition ratio shown in Table 7. The mixed powder thus obtained was subjected to a pressure of 4 ton / cm 2
CIP molding (cold isostatic molding) at φ40x80m
m was obtained. 1.3 x 1
1300 ° C. in a vacuum of 0 ⁻³ Pa (1 × 10 ⁻⁵ torr)
It was heated for 16 hours and sintered to obtain a sintered body. further,
This sintered body was hot forged in the air at 700 to 1150 ° C. to form a φ10 mm round bar, which was used as a test material C1.

B. Specimen C2 Specimen C2 relates to a titanium alloy containing more than 60% by mass of a Va group element. Using titanium powder, niobium powder, vanadium powder, and tantalum powder as raw material powders, they were blended so as to have the composition ratios shown in Table 7. Thereafter, a test material C2 was manufactured in the same manner as the test material C1. c. Specimen C3 Specimen C3 relates to a titanium alloy containing more than 5% by mass of aluminum. As a raw material powder, a titanium powder and a niobium powder, a tantalum powder, a zirconium powder, and an aluminum powder were blended so as to have a composition ratio shown in Table 7. Thereafter, a test material C3 was manufactured in the same manner as the test material C1.

D. Specimen C4 Specimen C4 relates to a titanium alloy containing more than 0.6% by mass of oxygen. As raw material powder, titanium powder,
A niobium powder and a tantalum powder were blended so as to have a composition ratio shown in Table 7. The oxygen content was adjusted by the oxygen content of the titanium powder. After this, the test material C
Specimen C4 was produced in the same manner as in No. 1. e. Specimen C5 Specimen C5 relates to a titanium alloy containing more than 1.0% by mass of boron. Using titanium powder, niobium powder, tantalum powder, and TiB2 powder as raw material powders, they were blended so as to have the composition ratios shown in Table 7. Thereafter, a test material C5 was manufactured in the same manner as the test material C1.

(2) Samples D1 to D3 Samples D1 to D3 were produced by a so-called melting method. a. Test Material D1 Titanium powder, niobium powder, hafnium powder, and tin powder were prepared as raw material powders, and a titanium alloy having a component composition shown in Table 7 was melted by button melting. The ingot thus obtained is hot forged in an atmosphere of 950 to 1050 ° C.
A round bar of 10 × 50 mm was used. b. Test material D2 Titanium powder, vanadium powder and aluminum powder were used as raw material powders and blended so as to have the composition ratios shown in Table 7. Thereafter, a test material D2 was manufactured in the same manner as the test material D1.

C. Test Material D3 Titanium powder, niobium powder, and zirconium powder were used as raw material powders and blended in the composition ratio shown in Table 7. After that, the test material D
3 was produced.

(Characteristics of Each Test Material) For each of the test materials described above, various characteristic values were determined by the following methods. a. Average Young's modulus, tensile elastic limit strength, elastic deformability, and tensile strength For each test material, a tensile test was performed using an Instron tester, and the load and elongation were measured. A diagram was obtained. The Instron testing machine is a universal tensile testing machine manufactured by Instron (manufacturer), and the driving system is an electric motor control system. The elongation was measured from the output of a strain gauge attached to the side surface of the test piece. The average Young's modulus, the tensile elastic limit strength, and the tensile strength were determined by the above-described method based on the stress-elongation (strain) diagram. In addition, the elastic deformability was obtained by elongating the tensile elastic limit strength from a stress-elongation (strain) diagram.

B. Others The porosity means the volume percentage of the above-mentioned pores, and the cold working rate means the cold working rate obtained from the above-mentioned formula. These results are also shown in Tables 1 to 7.

[0115]

[Table 1]

[0116]

[Table 2]

[0117]

[Table 3]

[0118]

[Table 4]

[0119]

[Table 5]

[0120]

[Table 6]

[0121]

[Table 7]

(Evaluation of each specimen) a. Average Young's modulus and tensile elastic limit strength All specimens 1 to 13 contain 30 to 60% by mass of a Va group element and have an average Young's modulus of 75 GPa. Below, the tensile elastic limit strength is 700 MPa or more. Therefore, it is understood that a sufficiently low Young's modulus and high strength (high elasticity) are achieved. On the other hand, the average Young's modulus of the test material C1 having a content of the Va group element of less than 30% by mass and the test materials C1 to D3 or the test material C2 having the content of the Va group element of more than 60% is less than 30% by mass. Exceeding 75 GPa, a low Young's modulus has not been achieved. Next, the test materials 14 to 24 containing Zr, Hf, or Sc in a predetermined amount of the Va group element were used as the test materials 6 to 12.
As is apparent from comparison with the above, in each case, a lower Young's modulus and a higher strength (high elasticity) are achieved.

Further, Cr, Mo, Mn, Fe, Co, N
The test materials 25 to 38 containing i, Al, and Sn have improved tensile elastic limit strength while achieving a lower Young's modulus than other test materials not containing these elements. Therefore, it is understood that these elements are effective for increasing the strength (high elasticity) of the titanium alloy according to the present invention. However, as can be seen from the test material C3 and the like, when the Al content exceeds 5% by mass, the tensile elastic limit strength is improved, but the average Young's modulus is also increased. It can be seen that in order to have a low Young's modulus and high strength (high elasticity), the Al content is preferably 5% or less. Further, from the test materials 39 to 46 containing a relatively large amount of oxygen, it is understood that oxygen is an effective element for achieving low Young's modulus and high strength (high elasticity). Also,
From the test materials 47 to 51, carbon and nitrogen
It is understood that the element is effective in achieving low Young's modulus and high strength (high elasticity). In addition, it is understood from the test materials 52 to 54 that boron is also an effective element for achieving low Young's modulus and high strength (high elasticity). Moreover, from the test materials 71 to 73,
Addition of an appropriate amount of boron does not impair cold workability.

B. Elastic Deformability Each of the test materials 1 to 84 has an elastic deformability of 1.3 or more, and the test materials C1 to C5 and D1 to D3 (the elastic deformability is 1.0 or less). On the other hand, it is understood that it has an excellent high elastic deformation ability. c. About cold working rate From the test materials 55 to 77 that have been subjected to cold working, in general, as the cold working rate increases, the average Young's modulus tends to decrease and the tensile elastic limit strength tends to increase. I understand. It can be seen that cold working is effective in achieving both a low Young's modulus, a high elastic deformation capability, and a high strength (high elasticity) of a titanium alloy.

D. Porosity From the test materials 78 to 81, it can be seen that high strength (high elasticity) as well as low Young's modulus was obtained even when vacancies of 30% by mass or less existed. And the test material 8 having a larger porosity
In the cases of 0 and 81, the specific strength is improved by lowering the density. e. About the sintering method and the melting method
Comparing with the test materials D1 to D3 produced by the melting method, it is understood that the sintering method makes it easy to obtain a titanium alloy having a low Young's modulus, a high elastic deformability and a high strength (high elasticity). On the other hand, it is difficult to achieve both low Young's modulus and high strength (high elasticity) in a titanium alloy obtained by a melting method like the test materials D1 to D3. However, this does not mean that titanium alloys produced by the melting method are excluded from the present invention, as can be seen from the test materials 2, 7 and the like.

[0126]

As described above, the titanium alloy of the present invention can be widely used for various products requiring low Young's modulus, high elastic deformation capacity and high strength (high elasticity). Because of its excellent workability, productivity can be improved. According to the method for producing a titanium alloy of the present invention, such a titanium alloy can be easily obtained.

[Brief description of the drawings]

FIG. 1A is a diagram schematically showing a stress-elongation (strain) diagram of a titanium alloy according to the present invention. B is a diagram schematically showing a stress-elongation (strain) diagram of a conventional titanium alloy.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C22F 1/00 C22F 1/00 630K 673 673 683 683 685 685Z (72) Inventor Wakage Nishino Aichi-gun, Aichi No. 41, Toyota Chuo R & D Co., Ltd. (72) Inventor Hiroyuki Takamiya Hirochi Takamiya, 41-41, Nagachute-cho Ochi-Cho Yokomichi, Aichi-gun, Aichi F-term (reference) 4K018 AA06 BA03 BB04 BC12 CA21 CA23 DA21 DA32 DA33 EA16 FA05 KA70

Claims (17)

[Claims] An object of the present invention is to contain at least a Va group (vanadium group) element and titanium (Ti) as a main component, and to apply a stress of 0 to a true permanent set of 0.2 in a tensile test.
% Of the tangent line on the stress-strain diagram obtained by the tensile test within the elastic deformation range up to the tensile elastic limit strength defined as the stress when the stress reaches%. A titanium alloy characterized by exhibiting the following characteristics. 2. The titanium alloy according to claim 1, further comprising at least one element in a group of metal elements consisting of zirconium (Zr), hafnium (Hf) and scandium (Sc). 3. The titanium alloy according to claim 1, further comprising at least one of oxygen (O), nitrogen (N) and carbon (C). 4. The method according to claim 1, further comprising chromium (Cr) and molybdenum (M).
o), manganese (Mn), iron (Fe), and cobalt (C
The titanium alloy according to any one of claims 1 to 3, comprising one or more elements in a metal element group consisting of o) and nickel (Ni). 5. The titanium alloy according to claim 1, further comprising aluminum (Al). 6. The method according to claim 1, further comprising boron (B).
The titanium alloy according to any one of the above. 7. The titanium alloy according to claim 1, which is a sintered alloy. 8. The sintered alloy has 5 pores by hot working.
The titanium alloy according to claim 7, which has a structure densified to not more than% by volume. 9. The titanium alloy according to claim 1, having a cold work structure of 10% or more. 10. A mixing step of mixing at least two or more kinds of raw material powders containing titanium and a Va group element, a forming step of forming the mixed powder obtained in the mixing step into a formed body having a predetermined shape, And a sintering step of heating and sintering the compact obtained in the compacting step. The obtained sintered alloy has a permanent set of 0.2 from a stress applied of 0 to a true permanent set in a tensile test.
% Of the tangent line on the stress-strain diagram obtained by the tensile test within the elastic deformation range up to the tensile elastic limit strength defined as the stress when the stress reaches%. A method for producing a titanium alloy, comprising the steps of: 11. The method for producing a titanium alloy according to claim 10, wherein said raw material powder comprises at least two kinds of pure metal powder and / or alloy powder. 12. A filling step of filling a raw material powder containing titanium and at least a Va group element into a container having a predetermined shape, and after the filling step, using a hot isostatic method (HIP method), the raw material in the container is filled. The sintering step involves sintering the powder. The obtained sintered alloy has a permanent set of 0.2 from a stress applied of 0 to a true permanent set in a tensile test.
% Of the tangent line on the stress-strain diagram obtained by the tensile test within the elastic deformation range up to the tensile elastic limit strength defined as the stress when the stress reaches%. A method for producing a titanium alloy characterized by exhibiting the following characteristics. 13. The raw material powder comprises titanium and at least V
13. The titanium alloy according to claim 12, comprising an alloy powder containing a group a element. 14. The method for producing a titanium alloy according to claim 10, wherein said raw material powder further contains at least one element in a group of metal elements consisting of Zr, Hf and Sc. 15. The raw material powder further comprises Cr, Mn,
The composition containing at least one or more elements of Co, Ni, Mo, Fe, Sn, Al, O, C, N and B.
5. The method for producing a titanium alloy according to any one of 4. 16. The titanium alloy according to claim 10, further comprising a hot working step of hot working the sintered body obtained after the sintering step to densify the structure of the sintered body. Manufacturing method. 17. The method for producing a titanium alloy according to claim 10, further comprising a cold working step of cold forming the sintered body obtained after the sintering step into a material or a product.