A method for rapidly preparing high-performance powder titanium alloy based on titanium hydride raw material

Abstract

The present invention relates to a method for rapidly preparing a high-performance powder titanium alloy based on a titanium hydride raw material, and belongs to the technical field of powder titanium alloy preparation. Low-cost titanium hydride powder raw material is used, and a titanium alloy powder sintered blank is prepared by microwave sintering in a protective atmosphere, and then induction heating and rapid die forging are performed to finally complete the preparation of a powder titanium alloy component. The method of the present invention has a simple process and can achieve rapid preparation of a high-performance powder titanium alloy. By utilizing the characteristics of microwave sintering and high heating rate of induction heating, the hydrogen element in the titanium hydride raw material is retained during the heating process, and the diffusion capacity of the titanium alloy element is improved, thereby improving the sintering activity and promoting densification during the forming process. The prepared powder titanium alloy has high density, fine grains, and excellent comprehensive mechanical properties.

Description

Technical Field

[0001] The invention belongs to the technical field of powder titanium alloy preparation, and in particular relates to a method for rapidly preparing high-performance powder titanium alloy based on titanium hydride raw material. Background Art

[0002] Titanium alloy is known as the third metal. It has the advantages of high specific strength, corrosion resistance, and biocompatibility. It is widely used in aerospace, marine engineering, biomedicine and other fields. Traditional titanium alloys are produced by ingot metallurgy, which requires multiple vacuum consumable melting to prepare ingots, and then a complex thermal processing process to improve the organization and performance of the alloy. This method has complex production procedures, long production cycles, and high costs.

[0003] Powder metallurgy technology can use elemental powder as raw material to prepare titanium alloy parts with a size close to the final part through forming and sintering. Therefore, powder metallurgy technology can naturally avoid complex processes such as vacuum consumable melting of titanium alloys, and can greatly shorten the production process of titanium alloys. Its near-net forming characteristics solve the problem of low utilization rate of ingot metallurgical materials. Titanium alloy parts prepared by powder metallurgy technology have uniform composition and fine grains, which not only avoids the problem of component segregation in the smelting process, but also reduces dependence on hot working processes. Therefore, powder metallurgy technology provides a new route to reduce the production cost of titanium alloy parts.

[0004] However, there are also many problems in the application of powder metallurgy technology in titanium alloys. For example, titanium alloy powder is easily oxidized, which increases the overall oxygen content of the powder titanium alloy, resulting in high strength of the alloy but greatly reduced plasticity. In addition, the powder metallurgy process for preparing titanium alloys is prone to the formation of residual pores in the alloy, which also has a serious impact on the mechanical properties of the alloy.

[0005] In order to improve the density of powder titanium alloy and thus enhance the comprehensive mechanical properties of the alloy, subsequent hot processing of the titanium alloy powder sintered blank is a simple and effective means, which not only improves the density of the material, but also enables the final forming of the powder blank. Hydrogen can improve the sintering density of titanium alloy, reduce the impurity content in the alloy, and improve the plastic deformation ability of the alloy. Therefore, using titanium hydride powder as the main raw material and using hydrogen to promote the diffusion ability of titanium atoms can improve the sintering density.

[0006] However, titanium hydride is easily decomposed at high temperatures. In order to obtain a powder sintered blank containing a certain hydrogen content, a hydrogen or hydrogen-argon mixed atmosphere is required, which increases the safety risk of the process to a certain extent. Summary of the invention

[0007] In response to the problems raised in the background technology, the present application provides a method for rapidly preparing high-performance powder titanium alloy based on titanium hydride raw material.

[0008] The objective of the present invention is achieved through the following technical solutions:

[0009] The method for rapidly preparing high-performance powder titanium alloy based on titanium hydride raw material proposed in the present invention specifically comprises the following steps:

[0010] S1: Mechanically mix the raw titanium hydride powder and the master alloy powder according to the nominal composition ratio of the titanium alloy;

[0011] S2: subjecting the mixed powder obtained in step S1 to cold isostatic pressing;

[0012] S3: subjecting the powder subjected to cold isostatic pressing in step S2 to powder microwave sintering to obtain a powder sintered blank, keeping the powder in the heat for a period of time and then cooling the blank in a furnace;

[0013] S4: induction heating and cooling the powder sintered compact obtained in step S3;

[0014] S5: Rapidly die forging and cooling the powder sintered blank after induction heating in step S4;

[0015] S6: The powder sintered blank obtained by rapid die forging in step S5 is subjected to vacuum dehydrogenation annealing, and then heat-insulated and cooled to obtain a high-performance powder titanium alloy.

[0016] Furthermore, the average particle size of the titanium hydride powder is 13 to 150 μm; the average particle size of the intermediate alloy powder is 13 to 150 μm.

[0017] Furthermore, the average oxygen content of the titanium hydride powder is in the range of 0 to 0.25 wt %.

[0018] Furthermore, in step S1, the mechanical mixing process of the raw titanium hydride powder and the intermediate alloy powder is carried out under vacuum or protective atmosphere.

[0019] Furthermore, in step S2, the pressing pressure of the cold isostatic pressing process is 150-400 MPa.

[0020] Furthermore, in step S3, the sintering temperature of the microwave sintering process is 1050-1350°C, the heating rate is ≥50°C / min when the sintering temperature is below 750°C, and the holding time is 5-60min.

[0021] Furthermore, in step S4, the induction heating is performed in a protective atmosphere or in air; when the induction heating is performed in air, the heating time does not exceed 15 minutes.

[0022] Furthermore, in step S5, the forging temperature of the rapid die forging process is not lower than the β / α+β transformation temperature T β Below 60℃, not higher than 1200℃, average deformation rate ≥1s-1 , the overall deformation is ≥30%.

[0023] Furthermore, in step S6, the vacuum pressure of the vacuum dehydrogenation annealing process is ≤10 -2 Pa, annealing temperature is 250~450℃, and holding time is 0.5~3h.

[0024] The method for rapidly preparing high-performance powder titanium alloy based on titanium hydride raw material proposed in the present invention has the following beneficial effects:

[0025] This method utilizes the characteristics of microwave sintering and high heating rate of induction heating to retain the hydrogen element in the titanium hydride raw material during the heating process, thereby improving the diffusion capacity of titanium alloy elements, thereby improving the sintering activity and promoting densification during the forming process. The prepared powder titanium alloy has high density, fine grains and excellent comprehensive mechanical properties.

[0026] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow chart of the method for rapidly preparing high-performance powder titanium alloy based on titanium hydride raw material proposed by the present invention;

[0028] Figure 2 The alloy microstructure of the high performance powder titanium alloy prepared in Example 3 of the present invention;

[0029] Figure 3 This is the tensile stress-strain curve of the high-performance powder titanium alloy prepared in Example 3 of the present invention at room temperature. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] This embodiment proposes a method for rapidly preparing a high-performance powder titanium alloy based on a titanium hydride raw material. The prepared titanium alloy is TC4. The preparation method specifically includes the following steps:

[0033] S1: Titanium hydride powder with an average particle size of 45 μm and Al-V40 master alloy powder with an average particle size of 45 μm are mixed in a ratio of Ti-6Al-4V and mechanically mixed in a V-type mixer for 12 hours;

[0034] S2: After the mixed powder is packaged, cold isostatic pressing is performed at a pressure of 350 MPa to obtain a powder compact;

[0035] S3: subjecting the powder compact to microwave sintering in an argon atmosphere, wherein the sintering temperature is 1250°C, the heating rate below 750°C is 70°C / min, and the powder compact is kept at this temperature for 30 minutes and then cooled in the furnace;

[0036] S4: The sintered alloy is subjected to induction heating in air for 15 min;

[0037] S5: The alloy after induction heating is rapidly forged at 970℃, and the deformation rate during forging is 30s -1 , the overall deformation is 50%, followed by air cooling;

[0038] S6: In 10 -2 Pa vacuum pressure, the alloy after rapid die forging was subjected to dehydrogenation vacuum heat treatment, the temperature was raised to 350°C annealing temperature at a heating rate of 10°C / min, and then cooled with the furnace after keeping warm for 1h; finally, the dehydrogenated TC4 titanium alloy forgings were obtained.

[0039] Example 2

[0040] This embodiment proposes a method for rapidly preparing a high-performance powder titanium alloy based on a titanium hydride raw material. The prepared titanium alloy is TA19. The preparation method specifically includes the following steps:

[0041] S1: Titanium hydride powder with an average particle size of 45 μm and Al-V40 master alloy powder with an average particle size of 45 μm are mixed according to the ratio of Ti-6Al-2Sn-4Zr-2Mo, and mechanically mixed for 12 hours in a V-type mixer;

[0042] S2: After the mixed powder is packaged, cold isostatic pressing is performed at a pressure of 400 MPa to obtain a powder compact;

[0043] S3: subjecting the powder compact to microwave sintering in an argon atmosphere, wherein the sintering temperature is 1200°C, the heating rate below 750°C is 80°C / min, and the powder compact is kept at this temperature for 60 minutes and then cooled in the furnace;

[0044] S4: The sintered alloy is subjected to induction heating in a protective atmosphere for 20 min;

[0045] S5: The alloy after induction heating is rapidly forged at 1100°C, and the deformation rate during forging is 30s -1 , the overall deformation is 40%, followed by air cooling;

[0046] S6: In 10 -2Pa vacuum pressure, the alloy after rapid die forging was subjected to dehydrogenation vacuum heat treatment, the heating rate was increased to 400°C annealing temperature at a rate of 50°C / min, and then the alloy was cooled in the furnace after being kept for 2 hours; finally, the dehydrogenated TA19 titanium alloy forgings were obtained.

[0047] Example 3

[0048] This embodiment proposes a method for rapidly preparing a high-performance powder titanium alloy based on a titanium hydride raw material. The prepared titanium alloy is TC4. The preparation method specifically includes the following steps:

[0049] S1: Titanium hydride powder with an average particle size of 13 μm and Al-V40 master alloy powder with an average particle size of 13 μm are mixed in a ratio of Ti-6Al-4V and mechanically mixed for 12 h in a V-type mixer;

[0050] S2: After the mixed powder is packaged, cold isostatic pressing is performed at a pressure of 150 MPa to obtain a powder compact;

[0051] S3: subjecting the powder compact to microwave sintering in an argon atmosphere, wherein the sintering temperature is 1050°C, the heating rate below 750°C is 50°C / min, and the powder compact is kept at this temperature for 5 minutes and then cooled in the furnace;

[0052] S4: The sintered alloy is subjected to induction heating in a protective atmosphere for 15 min;

[0053] S5: The alloy after induction heating is T β Rapid die forging is performed at -60℃, and the deformation rate during forging is 1s -1 , the overall deformation is 30%, followed by air cooling;

[0054] S6: In 10 -2 Pa vacuum pressure, the alloy after rapid die forging was subjected to dehydrogenation vacuum heat treatment, the heating rate was increased to annealing temperature 250°C at a rate of 50°C / min, and then the alloy was kept warm for 0.5h and then cooled in the furnace; finally, the dehydrogenated TC4 titanium alloy forgings were obtained.

[0055] The alloy microstructure of the TC4 titanium alloy forging prepared in Example 3 is as follows: Figure 2 As shown, it can be observed that the grains have high density and small particle size; the tensile stress-strain curve of the TC4 titanium alloy forging prepared in Example 3 at room temperature is as shown in Figure 3 As shown, the tensile strength Rm=1020MPa, the elongation at break A=12.0%, and the data show that it has excellent comprehensive mechanical properties.

[0056] Example 4

[0057] This embodiment proposes a method for rapidly preparing a high-performance powder titanium alloy based on a titanium hydride raw material. The prepared titanium alloy is TA19. The preparation method specifically includes the following steps:

[0058] S1: Titanium hydride powder with an average particle size of 150 μm and Al-V40 master alloy powder with an average particle size of 150 μm are mixed in the proportion of Ti-6Al-2Sn-4Zr-2Mo and mechanically mixed in a V-type mixer for 12 hours;

[0059] S2: After the mixed powder is packaged, cold isostatic pressing is performed at a pressure of 400 MPa to obtain a powder compact;

[0060] S3: subjecting the powder compact to microwave sintering in an argon atmosphere, wherein the sintering temperature is 1350°C, the heating rate below 750°C is 100°C / min, and the powder compact is kept at this temperature for 60 minutes and then cooled in the furnace;

[0061] S4: The sintered alloy is subjected to induction heating in air for 15 min;

[0062] S5: The alloy after induction heating is rapidly forged at 1200℃, and the deformation rate during forging is 40s -1 , the overall deformation is 70%, followed by air cooling;

[0063] S6: In 10 -2 Pa vacuum pressure, the alloy after rapid die forging was subjected to dehydrogenation vacuum heat treatment, the heating rate was increased to 450°C annealing temperature at a rate of 10°C / min, and then the alloy was cooled in the furnace after being kept for 3 hours; finally, the dehydrogenated TA19 titanium alloy forgings were obtained.

[0064] Example 5

[0065] This embodiment proposes a method for rapidly preparing a high-performance powder titanium alloy based on a titanium hydride raw material. The prepared titanium alloy is TA19. The preparation method specifically includes the following steps:

[0066] S1: Titanium hydride powder with an average particle size of 81.5 μm and Al-V40 master alloy powder with an average particle size of 81.5 μm are mixed according to the ratio of Ti-6Al-2Sn-4Zr-2Mo, and mechanically mixed for 12 hours in a V-type mixer;

[0067] S2: After the mixed powder is packaged, cold isostatic pressing is performed at a pressure of 275 MPa to obtain a powder compact;

[0068] S3: subjecting the powder compact to microwave sintering in an argon atmosphere, wherein the sintering temperature is 1200°C, the heating rate below 750°C is 80°C / min, and the powder compact is kept at this temperature for 32.5 minutes and then cooled in the furnace;

[0069] S4: The sintered alloy is subjected to induction heating in a protective atmosphere for 30 min;

[0070] S5: The alloy after induction heating is rapidly forged at 1150℃, and the deformation rate during forging is 30s -1 , the overall deformation is 60%, followed by air cooling;

[0071] S6: In 10 -2 Pa vacuum pressure, the alloy after rapid die forging was subjected to dehydrogenation vacuum heat treatment, the heating rate was increased to annealing temperature 350°C at a rate of 10°C / min, and then the alloy was kept warm for 1.75h and then cooled in the furnace; finally, the dehydrogenated TA19 titanium alloy forgings were obtained.

[0072] Example 6

[0073] This embodiment proposes a method for rapidly preparing a high-performance powder titanium alloy based on a titanium hydride raw material. The prepared titanium alloy is TC4. The preparation method specifically includes the following steps:

[0074] S1: Titanium hydride powder with an average particle size of 13 μm and Al-V40 master alloy powder with an average particle size of 150 μm are mixed according to the ratio of Ti-6Al-4V and mechanically mixed in a V-type mixer for 12 hours;

[0075] S2: After the mixed powder is packaged, cold isostatic pressing is performed at a pressure of 150 MPa to obtain a powder compact;

[0076] S3: subjecting the powder compact to microwave sintering in an argon atmosphere, wherein the sintering temperature is 1350°C, the heating rate below 750°C is 50°C / min, and the powder compact is kept at this temperature for 5 minutes and then cooled in the furnace;

[0077] S4: The sintered alloy is subjected to induction heating in a protective atmosphere for 15 min;

[0078] S5: The alloy after induction heating is rapidly forged at 1200℃, and the deformation rate during forging is 10s -1 , the overall deformation is 40%, followed by air cooling;

[0079] S6: In 10 -2 Pa vacuum pressure, the alloy after rapid die forging was subjected to dehydrogenation vacuum heat treatment, the heating rate was increased to 450°C annealing temperature at a rate of 50°C / min, and then the alloy was kept warm for 0.5h and then cooled in the furnace; finally, the dehydrogenated TC4 titanium alloy forgings were obtained.

[0080] Example 7

[0081] This embodiment proposes a method for rapidly preparing a high-performance powder titanium alloy based on a titanium hydride raw material. The prepared titanium alloy is TC4. The preparation method specifically includes the following steps:

[0082] S1: Titanium hydride powder with an average particle size of 150 μm and Al-V40 master alloy powder with an average particle size of 13 μm are mixed according to the ratio of Ti-6Al-4V and mechanically mixed in a V-type mixer for 12 hours;

[0083] S2: After the mixed powder is packaged, cold isostatic pressing is performed at a pressure of 400 MPa to obtain a powder compact;

[0084] S3: subjecting the powder compact to microwave sintering in an argon atmosphere, wherein the sintering temperature is 1050°C, the heating rate below 750°C is 50°C / min, and the powder compact is kept at this temperature for 60 minutes and then cooled in the furnace;

[0085] S4: The sintered alloy is subjected to induction heating in air for 15 min;

[0086] S5: The alloy after induction heating is T β Rapid die forging is performed at -60℃, and the deformation rate during forging is 20s -1 , the overall deformation is 50%, followed by air cooling;

[0087] S6: In 10 -2 Pa vacuum pressure, the alloy after rapid die forging was subjected to dehydrogenation vacuum heat treatment, the heating rate was increased to annealing temperature 250°C at a rate of 50°C / min, and then cooled with the furnace after keeping warm for 3 hours; finally, the dehydrogenated TC4 titanium alloy forgings were obtained.

Claims

1. A method for rapidly preparing high-performance powder titanium alloy based on titanium hydride raw material, characterized in that: The specific steps include: S1: Mechanically mix the raw titanium hydride powder and the master alloy powder according to the nominal composition ratio of the titanium alloy; S2: subjecting the mixed powder obtained in step S1 to cold isostatic pressing; S3: subjecting the powder subjected to cold isostatic pressing in step S2 to powder microwave sintering to obtain a powder sintered blank, keeping the powder in the heat for a period of time and then cooling the blank in a furnace; S4: induction heating and cooling the powder sintered compact obtained in step S3; S5: Rapidly die forging and cooling the powder sintered blank after induction heating in step S4; S6: performing vacuum dehydrogenation annealing on the powder sintered blank obtained by rapid die forging in step S5, and obtaining a high-performance powder titanium alloy after heat preservation and cooling; The average particle size of the titanium hydride powder is 13 to 150 μm; the average particle size of the intermediate alloy powder is 13 to 150 μm; The average oxygen content of the titanium hydride powder is in the range of 0 to 0.25 wt %; In step S1, the mechanical mixing process of the raw titanium hydride powder and the master alloy powder is carried out under vacuum or protective atmosphere; In step S2, the pressing pressure of the cold isostatic pressing process is 150-400 MPa; In step S3, the sintering temperature of the microwave sintering process is 1050-1350°C, the heating rate is ≥50°C / min when the sintering temperature is below 750°C, and the holding time is 5-60min; In step S4, the induction heating is performed in a protective atmosphere or in air; when the induction heating is performed in air, the heating time does not exceed 15 minutes; In step S5, the forging temperature of the rapid die forging process is not lower than the β / α+β transformation temperature T β Below 60℃, not higher than 1200℃, average deformation rate ≥1s -1 , overall deformation ≥ 30%; In step S6, the vacuum pressure of the vacuum dehydrogenation annealing process is ≤10 -2 Pa, annealing temperature is 250~450℃, and holding time is 0.5~3h.

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