JPH05255780A - High strength titanium alloy having uniform and fine structure - Google Patents

Abstract

PURPOSE:To provide a titanium allay having a uniform and fine structure in which strength at ordinary temps. and high temps. is improved in an alpha type, alpha+beta type and beta type titanium alloy. CONSTITUTION:This alloy is a high strength titanium alloy having a uniform and fine structure characterized by adding, by weight, 0.1 to 3.0% Fe and 0.001 to 0.5% of one or >= two kinds among P, As, Sb, Bi, S, Se, Te and B to an alphatype, alpha+beta type and beta type titanium alloy.

Description

Detailed Description of the Invention

[0001]

The present invention relates to α type, α + β type and β type
The present invention relates to a titanium alloy having a uniform microstructure with improved strength at room temperature and high temperature.

[0002]

2. Description of the Related Art Titanium alloys are used in many structural material fields including aircraft parts because of their high specific strength, excellent corrosion resistance, and heat resistance. is there. In such a titanium alloy, which has been receiving attention in this way, its metallographic structure is composed of a hexagonal α phase α
Type, α + β type composed of α phase and body-centered cubic β phase, and β type composed of β phase.

For the α-type alloy, Ti-5Al-2.5Sn,
Ti-5.5Al and the like. Since it has higher strength than pure titanium and is always stable below the β transformation point, it has excellent thermal stability and creep resistance at high temperatures, and is used for aircraft engine cases and the like. For α + β type alloy, Ti-6Al-4V, Ti-3Al-2.5V, Ti-
6Al-2Sn-4Zr-2Mo and Ti-6Al-
2Sn-4Zr-6Mo alloy and the like. Since these are two-phase alloys, they are well-balanced materials that have excellent characteristics in terms of both workability and weldability, and other product characteristics such as strength and fatigue resistance. To be done. Ti-15V-3Cr- for β-type alloys
3Sn-3Al, Ti-3Al-8V-6Cr-4Mo
-4Zr, etc. Since these can retain the β phase even at room temperature, they have excellent cold workability, and high strength can be obtained by heat treatment. Therefore, they have been actively developed in recent years and have come to be used in various fields.

These titanium alloys are required to have a uniform and fine metal structure in order to further increase the strength and, in heat resistant applications, improve the heat resistant strength in a high temperature environment and the fatigue strength. Recently, with the expansion of applications, there has been a demand for a material having high strength from room temperature to high temperature compared with the conventional use environment. Titanium alloys may be used in the as-cast state depending on the application, or may be supplied after being molded into various shapes such as plates, wires, pipes and shapes after casting. However, the as-cast material has a problem that strength and ductility are poor due to the coarse cast structure, and the β transformation point (for example, Ti
-3 ° C with -3Al-2.5V, Ti-6Al-4V
In this case, it is necessary to carry out processing at a high working rate in a low temperature region of 990 ° C. or lower, and therefore, there is a problem that cracks occur in a titanium alloy having poor hot workability.

[0005]

DISCLOSURE OF THE INVENTION The present invention is of α type, α + β
It is an object of the present invention to provide a titanium alloy having a uniform fine structure with improved strength at room temperature and high temperature, in the β-type and β-type titanium alloys.

[0006]

The present inventor has added Fe to a titanium alloy and has added P, As, Sb, Bi, S, S.
It was found that when one or more of e, Te, and B are added in combination, the combined effect improves the strength in the as-cast material and the hot-worked material and obtains a uniform fine structure. In particular, since a uniform fine structure can be obtained as it is cast, it is characterized in that the restriction of the processing temperature range, which is the case in the conventional α + β region processing, can be relaxed even in the subsequent processing steps. The present invention is based on such knowledge, and the summary thereof is as follows.

(1) In an α-type, α + β-type or β-type titanium alloy, 0.1 to 3% by weight of Fe is added, and
And, the total of 0.001 to 0.5% by weight% of one or more of P, As, Sb, Bi, S, Se, Te and B.
A high-strength titanium alloy having a uniform microstructure characterized by being added. (2) In an α-type titanium alloy containing Al: 0.2 to 7% by weight and the balance of Ti and unavoidable impurities, 0.1 to 3% of Fe is added by weight, and P,
1 or 2 of As, Sb, Bi, S, Se, Te, B
A high-strength titanium alloy having a uniform microstructure, characterized in that a total of 0.001 to 0.5% by weight of the seeds is added. (3) Al: 0.2 to 7% and Sn: 1 to 1 by weight%
In an α-type titanium alloy containing 6% and the balance of Ti and unavoidable impurities, 0.1% by weight of Fe is 0.1% by weight.
3% added, and P, As, Sb, Bi, S, Se, T
One or two or more of e and B in total of 0.00 by weight%
A high-strength titanium alloy having a uniform microstructure characterized by being added in an amount of 1 to 0.5%. (4) V: 0.2 to 7% by weight, with the balance being T
In an α + β type titanium alloy consisting of i and unavoidable impurities, 0.1 to 3% of Fe is added by weight%, and one or two of P, As, Sb, Bi, S, Se, Te and B is added. A high-strength titanium alloy having a uniform microstructure, which is characterized by adding 0.001 to 0.5% by weight in total. (5) Al: 0.2 to 7% and V: 0.2% by weight
.About.12%, with the balance being Ti and unavoidable impurities, an .alpha. +. Beta.-type titanium alloy containing 0.1 to 3% of Fe by weight% and adding P, As, Sb, Bi, S,
A high-strength titanium alloy having a uniform microstructure, characterized in that one or more of Se, Te, and B are added in a total amount of 0.001 to 0.5% by weight. (6) Al: 0.2 to 7% by weight% and V: 0.2 to
12% or Mo: 1 to 7%, and Sn:
1 to 6%, Zr: 3 to 8%, Cu: 0.1 to 3% of one or more kinds, and the balance is an α + β type titanium alloy composed of Ti and unavoidable impurities. 0.1 to 3% of Fe is added, and P, As, Sb and B are added.
Weight percentage of one or more of i, S, Se, Te, B
A high-strength titanium alloy having a uniform microstructure characterized by being added in a total amount of 0.001 to 0.5%. (7) A total of 9 to 27% of 1 or 2 or more of V, Mo and Cr is contained by weight%, and Al: 0.2 to 4%,
Β containing 1: 1 or 2 or more of Sn: 1 to 6% and Zr: 3 to 8%, with the balance being Ti and inevitable impurities
Type titanium alloy, Fe is 0.1 to 3% by weight.
And P, As, Sb, Bi, S, Se, Te,
0.001 to 1 in total of 1 or 2 or more of B in% by weight.
A high-strength titanium alloy having a uniform microstructure characterized by being added at 0.5%.

The invention of claim 1 is α type, α + β type and β type
Type titanium alloy, Fe and P, As, Sb, B
By adding i, S, Se, Te and B, a uniform fine structure is obtained and the strength is improved. Ti-5Al-2.5Sn is a typical example of α-type alloy, and Ti-6Al-4V and Ti-3Al- is a typical example of α + β-type alloy.
Ti-15V-3C as a typical example of 2.5V, β type alloy
r-3Sn-3Al is selected, Fe, P and As, S
b, Bi, S, Se, Te, and B were added together to produce a bar, and a bar was manufactured. The tensile strength and the structure were examined.
As a result, P and As, Sb, Bi, S, Se, T
It has been found that the elements e and B form a compound with Ti and, together with Fe, finely disperse as a composite compound together with strengthening of the matrix and a uniform fine cast structure can be obtained. Further, with the refinement of the structure and the solid solution strengthening of Fe, P, etc., the strength is increased and at the same time the workability is improved. The effect is exhibited when Fe is added in an amount of 0.1% by weight or more and one or more elements such as P are added in a total amount of 0.001% by weight or more, and Fe is added in an amount of more than 3% by weight. In addition, when one or more elements such as P are added in a total amount of more than 0.5% by weight, the effect of refining the structure is not remarkable and the ductility is reduced.
When Fe is added in an amount of less than 0.1% by weight, or one or more elements such as P are added in a total amount of 0.001% by weight.
Less than 0.1% by weight of Fe and P
When one or more of these elements are added in a total amount of less than 0.001% by weight, it is difficult to recognize the uniform fine grain effect of the structure. Therefore, in the invention of claim 1, in the titanium alloy, F
0.1 to 3% by weight of e, and P, As, Sb, B
Weight percentage of one or more of i, S, Se, Te, B
It was decided to add 0.001 to 0.5% in total.
The effect of the present invention is remarkable also for a titanium alloy containing a large amount of unavoidable impurities in excess of the ASTM standard. For example, even if oxygen is contained in an amount of about 0.5% by weight, the titanium alloy according to the present invention has a uniform fine structure and high strength.

The invention of claim 2 is directed to an α-type titanium alloy represented by Ti-5.5Al. Al is contained for stabilizing the α phase and strengthening the solid solution, and the effect is exhibited at 0.2% by weight or more. When it exceeds 7% by weight, Ti ₃ A
Since the intermetallic compound precipitates and the workability deteriorates,
It was decided to contain 2 to 7% by weight. For the same reason as in claim 1, 0.1 to 3% by weight of Fe is added, and P and A are added.
One or two or more of s, Sb, Bi, S, Se, Te, and B are added in a total amount of 0.001 to 0.5% by weight.

The invention of claim 3 is Ti-5Al-2.5S.
The object is an α-type titanium alloy represented by n. For the same reason as in claim 2, Al is included in an amount of 0.2 to 7% by weight. Sn is included for solid solution strengthening, and its effect appears at 1% by weight or more. If it exceeds 6% by weight, the effect is saturated, so 1 to 6% by weight is included. Further, Fe is 0.1 to 3 for the same reason as in claim 1.
% By weight, and P, As, Sb, Bi, S, Se,
One or two or more of Te and B in total by weight of 0.0
It was decided to add 01 to 0.5%.

[0011] The invention of claim 4 is α such as Ti-2.5V
It is intended for + β type titanium alloys. V is contained for stabilizing the β phase, strengthening the solid solution, and improving workability, and the effect appears at 0.2% by weight or more. When V is contained alone, the α phase becomes unstable if it exceeds 7% by weight. So 0.2-7
It has been decided to contain it by weight%. For the same reason as in claim 1, 0.1 to 3% by weight of Fe is added, and P, As and S are added.
One or two or more of b, Bi, S, Se, Te, and B are added in a total amount of 0.001 to 0.5% by weight.

The invention of claim 5 is Ti-6Al-4V, T
It is intended for α + β type titanium alloys such as i-3Al-2.5V. As in claim 2, Al is contained in an amount of 0.2 to 7% by weight for stabilizing the α phase and strengthening the solid solution. V is included for stabilizing the β phase, strengthening the solid solution and improving the workability, and the effect appears at 0.2% by weight or more.
If it exceeds 2% by weight, the α phase becomes unstable, so 0.2 to 1
It was decided to contain 2% by weight. For the same reason as in claim 1, 0.1 to 3% by weight of Fe is added, and P, As,
One or two or more kinds of Sb, Bi, S, Se, Te and B are added in a total amount of 0.001 to 0.5% by weight.

The invention of claim 6 is Ti-6Al-2Sn-
4Zr-2Mo, Ti-6Al-6V-2Sn, Ti-
It is intended for α + β type titanium alloys such as 6Al-2Sn-4Zr-6Mo. Al is α as in claim 2.
In order to stabilize the phase and strengthen the solid solution, 0.2 to 7% by weight is included. V or Mo is contained for stabilizing the β phase, strengthening the solid solution, and improving the workability. The effect is that V is 0.2% by weight or more and Mo is 1% by weight or more.
Is more than 12% by weight, and if Mo is more than 7% by weight, the α phase becomes unstable, so V is 0.2 to 12% by weight.
The content of Mo is determined to be 1 to 7% by weight. Sn, Zr, and Cu are all effective elements for solid solution strengthening, Sn is 1 wt% or more, Zr is 3 wt% or more,
Cu has an effect when it is 0.1% by weight or more. However, Sn
When the content of Zr exceeds 6% by weight, the effect is saturated when Zr exceeds 8% by weight, and the eutectoid compound precipitates and the workability deteriorates when Cu exceeds 3% by weight. Therefore, Sn: 1-6
% By weight, Zr: 3-8% by weight, Cu: 0.1-3% by weight
1 type or 2 types or more of these were included. For the same reason as in claim 1, 0.1 to 3% by weight of Fe is added,
And, the total of 0.001 to 0.5% by weight% of one or more of P, As, Sb, Bi, S, Se, Te and B.
It was decided to add.

The invention of claim 7 is Ti-13V-11Cr.
-3Al, Ti-3Al-8V-6Cr-4Mo-4Z
r (βc alloy), Ti-11.5Mo-6Zr-4.5
Sn (βIII alloy), Ti-15V-3Cr-3Sn-
It is intended for β-type titanium alloys such as 3Al.
V, Mo, and Cr are contained for stabilizing the β phase, strengthening the solid solution, and improving the workability. The effect of one or more of these elements is 9 wt% or more, but 27 wt% If these values are exceeded, segregation of these elements is liable to occur and improvement in product properties such as fatigue properties cannot be expected, and the specific gravity increases and the high specific strength characteristic of titanium alloys is impaired. The above content is to be contained in a total of 9 to 27% by weight. Al, Sn and Zr are all effective elements for solid solution strengthening. Al and Sn further have the effect of suppressing the embrittlement of the material due to the precipitation of the ω phase. The effect appears when Al is 0.2 wt% or more and Sn is 1 wt% or more, and Zr is Further, it has an effect of stabilizing the β phase, and the effect appears at 3% by weight or more. But Al
Is more than 4% by weight, the β phase becomes unstable, and the effect is saturated when Sn exceeds 6% by weight and when Zr exceeds 8% by weight. Therefore, Al: 0.2 to 4% by weight, S
n: 1 to 6% by weight, Zr: 3 to 8% by weight, 1 or 2
It was decided to contain more than one seed. For the same reason as in claim 1, 0.1 to 3% by weight of Fe is added, and P, As,
One or two or more kinds of Sb, Bi, S, Se, Te and B are added in a total amount of 0.001 to 0.5% by weight.

The titanium alloy according to the present invention can be used as an as-cast material, or by subjecting the cast material to hot-rolling, hot-extrusion and, if necessary, cold-rolling, etc., to obtain various materials such as plates, wires, rods and shapes. It can be provided as a shape, and can also be provided as a welded structural material obtained by performing a welding process on these and a welding material at the time of welding. Further, it can be provided as a powder molding material. In particular, since it is possible to obtain a fine structure even in the as-cast state, restrictions on the processing temperature range can be relaxed in subsequent processing steps, and heat treatment conditions can also be relaxed in a similar manner. It has features such as processing. Furthermore, when the material according to the present invention is processed and heat-treated in the conventional condition range, a more uniform and finer structure can be obtained.

[0016]

Example Various titanium alloys having the components shown in Table 1 were melted and cast. Then, after heating to 1100 ° C., a tensile test piece with a diameter of 10 mm was made from a round bar manufactured by hot extrusion at room temperature and 4
A high temperature tensile test at 00 ° C was performed to measure the proof stress. As a result, as shown in Table 1, all of the present inventions are excellent in room temperature and high temperature strength as compared with the conventional example, and the cast material structures of the present invention examples are all fine and uniform structures as compared with the conventional example. there were. As a representative example thereof, the invention example No. 12 and No. 12 of the conventional example as a comparison. The metallographic structure of the as-cast material 54 is shown in FIGS. 1 and 2. The effect of refining the structure according to the present invention is clear. In addition, No. of the comparative example in which the addition amount of P or O was excessive. Nos. 42, 44, 46, 47 and 51 were hot extruded but cracked.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

[0020]

According to the present invention, α type, α + β type and β type
Type titanium alloy material, excellent at room temperature and high temperature strength,
Further, a material having a fine uniform structure is provided, the characteristics of the titanium alloy having a high specific strength and good corrosion resistance are maintained, and it can be used at a higher temperature than before. Further, it becomes possible to provide a material having excellent strength and ductility, which has a fine and uniform structure even in the as-cast material, and its industrial effect is remarkable.

[Brief description of drawings]

FIG. 1 is a 200 × magnified micrograph showing the metal structure of a material of the present invention (No. 12 in Table 1).

FIG. 2 shows a metallographic structure of a conventional material (No. 54 in Table 1) 2
00x magnified micrograph.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiro Hanamura 1618 Ida, Nakahara-ku, Kawasaki-shi, Kanagawa Inside Nippon Steel Corporation Advanced Technology Research Institute (72) Inventor, Shinichi Takamura Ida, Nakahara-ku, Kawasaki-shi, Kanagawa Address 1618 Nippon Steel Corporation Advanced Technology Research Center

Claims (7)

[Claims] 1. In an α-type, α + β-type or β-type titanium alloy, 0.1 to 3% by weight of Fe is added, and 1 of P, As, Sb, Bi, S, Se, Te and B is added. A high-strength titanium alloy having a uniform microstructure, characterized in that 0.001 to 0.5% by weight of a total of 0.001 to 0.5% is added. 2. An α-type titanium alloy containing Al: 0.2 to 7% by weight and the balance of Ti and inevitable impurities, and 0.1 to 3% of Fe added by weight. , And one or two or more of P, As, Sb, Bi, S, Se, Te, and B in total by weight of 0.001 to 0.
A high-strength titanium alloy having a uniform microstructure characterized by being added at 5%. 3. Al: 0.2 to 7% in weight percent and S
In an α-type titanium alloy containing 1: 1 to 6% of n and the balance of Ti and unavoidable impurities, 0.1 to 3% of Fe is added by weight%, and P, As, Sb, Bi and S are added. ，
A high-strength titanium alloy having a uniform microstructure, characterized in that one or more of Se, Te, and B are added in a total amount of 0.001 to 0.5% by weight. 4. V: 0.2 to 7% in weight%,
In an α + β titanium alloy with the balance being Ti and unavoidable impurities, 0.1 to 3% of Fe is added by weight%, and one of P, As, Sb, Bi, S, Se, Te, and B, or A total of two or more kinds by weight% is 0.001 to 0.
A high-strength titanium alloy having a uniform microstructure characterized by being added at 5%. 5. An α + β type titanium alloy containing Al: 0.2 to 7% and V: 0.2 to 12% by weight, the balance being Ti and inevitable impurities.
At 0.1 to 3% of Fe, and P, As, Sb,
A high-strength titanium alloy having a uniform microstructure, characterized in that one or more of Bi, S, Se, Te, and B are added in a total amount of 0.001 to 0.5% by weight. 6. A weight ratio of Al: 0.2 to 7% and V:
0.2 to 12% or Mo: 1 to 7%, Sn: 1 to 6%, Zr: 3 to 8%, Cu: 0.1 to 3%
% In an α + β type titanium alloy containing at least one of Ti and unavoidable impurities, and 0.1% to 3% of Fe is added by weight% and P, As and S are added.
A high-strength titanium alloy having a uniform microstructure, wherein one or more of b, Bi, S, Se, Te, and B are added in a total amount of 0.001 to 0.5% by weight. 7. A total of 9 to 27% by weight of one or more of V, Mo and Cr, and further Al: 0.2.
.About.4%, Sn: 1 to 6%, Zr: 3 to 8%, and a balance of Ti and unavoidable impurities in the .beta.-type titanium alloy containing 0 or less Fe. ．
1-3% added, and P, As, Sb, Bi, S, S
A high-strength titanium alloy having a uniform microstructure, wherein one or more of e, Te, and B are added in a total amount of 0.001 to 0.5% by weight.