阅读说明：本技术 粉末冶金钛或钛合金制品及其短流程制备方法 (Powder metallurgy titanium or titanium alloy product and short-process preparation method thereof ) 是由 路新 张策 郭志猛 杨芳 刘博文 潘宇 徐伟 曲选辉 于 2020-05-21 设计创作，主要内容包括：本发明提供了一种粉末冶金钛或钛合金制品及其短流程制备方法,该制备方法包括以下步骤：选取钛或钛合金为原料,并且所述原料的至少一个维度的尺寸≤5mm；将所述原料进行不饱和氢化处理；将经过不饱和氢化处理后的所述原料进行低温破碎处理,得到不饱和氢化钛粉末；将所述不饱和氢化钛粉末依次进行成形及烧结处理,得到钛或钛合金制品。该制备方法利用部分吸氢后物料的脆性并结合低温破碎技术将物料破碎为粉末,后续将粉末直接冷等静压成形和真空烧结致密化制备钛及钛合金材料,省略了脱氢过程,实现了短流程制备粉末钛合金产品,成材率高,成本低,产品性能优异。(The invention provides a powder metallurgy titanium or titanium alloy product and a short-process preparation method thereof, wherein the preparation method comprises the following steps: selecting titanium or titanium alloy as a raw material, wherein the size of at least one dimension of the raw material is less than or equal to 5 mm; subjecting the feedstock to an unsaturated hydrogenation treatment; carrying out low-temperature crushing treatment on the raw material subjected to unsaturated hydrogenation treatment to obtain unsaturated titanium hydride powder; and sequentially forming and sintering the unsaturated titanium hydride powder to obtain the titanium or titanium alloy product. According to the preparation method, the brittleness of the material after partial hydrogen absorption is combined with a low-temperature crushing technology to crush the material into powder, and the powder is directly subjected to isostatic cool pressing and vacuum sintering densification to prepare the titanium and titanium alloy material, so that a dehydrogenation process is omitted, the powder titanium alloy product is prepared in a short process, the yield is high, the cost is low, and the product performance is excellent.)

1. A short-process preparation method of a powder metallurgy titanium or titanium alloy product is characterized by comprising the following steps:

s1: preparing a raw material, namely selecting titanium or titanium alloy as the raw material, wherein the size of at least one dimension of the raw material is less than or equal to 5 mm;

s2: hydrogenation, namely, carrying out unsaturated hydrogenation treatment on the raw material in the step S1;

s3: crushing, namely performing low-temperature crushing treatment on the raw material subjected to the unsaturated hydrogenation treatment in the step S2 to obtain unsaturated titanium hydride powder;

s4: and (4) sequentially carrying out forming and sintering treatment on the unsaturated titanium hydride powder obtained in the step (S3) to obtain a titanium or titanium alloy product.

2. The short-run method for preparing a powder metallurgy titanium or titanium alloy product according to claim 1, wherein in step S2, the hydrotreating process comprises:

s2-1: vacuum pumping is carried out to 10^-3～10^-1Pa, heating to 450-550 ℃, and preserving heat for 30-60 min;

s2-2: introducing high-purity hydrogen and controlling the hydrogen absorption amount;

s2-3: and carrying out hydrogen homogenization treatment.

3. The short-process preparation method of powder metallurgy titanium or titanium alloy products according to claim 2, wherein in step S2-2, the hydrogen absorption amount is controlled to be 1.0 to 2.5 wt.%.

4. The short-process preparation method of the powder metallurgy titanium or titanium alloy product according to claim 2, wherein in step S2-3, the hydrogen homogenization treatment is specifically: after the hydrogen introduction is stopped, the temperature is raised to 550-850 ℃ again, and the temperature is kept for 2-5 h.

5. The short-process preparation method of powder metallurgy titanium or titanium alloy products according to claim 1, wherein in step S3, the low-temperature crushing treatment adopts a low-temperature mechanical crushing process, wherein the low-temperature medium is liquid argon.

6. The short-process preparation method of powder metallurgy titanium or titanium alloy products according to claim 1, wherein in step S3, the particle size of the unsaturated titanium hydride powder is 10-75 μm.

7. The short-process preparation method of a powder metallurgy titanium or titanium alloy product according to claim 1, wherein in step S4, the forming treatment is a cold isostatic pressing process, wherein the pressing pressure is 150-200 MPa, and the dwell time is 10-30S.

8. The short-process preparation method of powder metallurgy titanium or titanium alloy products according to claim 7, wherein in step S4, the sintering treatment is specifically: and carrying out vacuum sintering densification on the blank obtained by the cold isostatic pressing forming process by adopting a sectional sintering process.

9. The short-process preparation method of a powder metallurgy titanium or titanium alloy product according to claim 8, wherein the step sintering process specifically comprises:

the first section is heated to 550-750 ℃, the heating rate is 2 ℃/min, the temperature is kept for 2-10 h, and the removal of the residual hydrogen content is completed;

and heating the second section to 1150-1300 ℃, wherein the heating rate is 5 ℃/min, the sintering time is 2-5 h, and the densification is completed.

10. The powder metallurgy titanium or titanium alloy product prepared by the short-process preparation method of the powder metallurgy titanium or titanium alloy product according to any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of powder metallurgy, in particular to a powder metallurgy titanium or titanium alloy product and a short-process preparation method thereof.

Background

Titanium and titanium alloy have excellent comprehensive properties, such as small density, high specific strength, good fatigue strength, good crack expansion resistance and excellent corrosion resistance, so that the titanium and titanium alloy have increasingly wide application prospects in weaponry such as ships, weapons, aviation, aerospace and the like. However, the high production and processing cost of titanium is a main reason for limiting the wide application of titanium, so that the low cost is a general trend of the development of the titanium industry at present. Powder metallurgy is an effective method for preparing low-cost and high-performance titanium and titanium alloy in a short process, compact titanium alloy materials are not prepared by melting, and the problem of melting titanium as refractory metal is solved; meanwhile, the near-net forming characteristic and the microstructure advantage reduce raw materials required by manufacturing final products and cogging forging processes, and solve the problems of low utilization rate of the smelting titanium alloy material and difficult hot working.

The Hydrogenation Dehydrogenation (HDH) titanium powder can be used for preparing powder metallurgy titanium alloy products, but the structure performance advantage of the powder metallurgy products cannot be exerted due to the influence of factors such as high interstitial atom content, low sintering compactness, large microstructure and the like. The current research shows that a proper amount of hydrogen can purify an oxide film on the surface of the powder in the sintering process of the HDH titanium powder, so that the sintering compactness is promoted, and meanwhile, the hydrogen can be used as a temporary alloy element to refine the microstructure of the titanium alloy. Therefore, (method CN101934373B) direct sintering using titanium hydride powder is used for preparing powder titanium alloy products, but in the aspect of practical engineering application, excessive hydrogen content not only causes the powder formability to be deteriorated, but also causes sintering cracking phenomenon of large-size blanks. For this reason, the researchers have proposed a sintering method (CN106191493A) of titanium powder doped with titanium hydride powder and a sintering method (CN107034375A) of partially dehydrogenated unsaturated titanium hydride sequentially, but both methods require dehydrogenation of titanium hydride powder, have long dehydrogenation time and low efficiency, and have serious powder hardening phenomenon, which is not favorable for preparation of ultrafine powder, so that the application of titanium alloy powder based on titanium hydride and titanium powder is severely restricted.

Disclosure of Invention

The invention mainly aims to provide a powder metallurgy titanium or titanium alloy product and a short-flow preparation method thereof, wherein the preparation method comprises the steps of crushing a material into powder by utilizing the brittleness of the material after partial hydrogen absorption and combining a low-temperature crushing technology, then preparing titanium and titanium alloy materials by directly carrying out cold isostatic pressing forming and vacuum sintering densification on the powder, and omitting a dehydrogenation process so as to solve the technical problem of low efficiency caused by dehydrogenation treatment in the preparation process of the powder metallurgy titanium or titanium alloy product in the prior art.

In order to achieve the above object, according to a first aspect of the present invention, there is provided a short-flow production method of a powder metallurgy titanium or titanium alloy article.

The short-process preparation method of the powder metallurgy titanium or titanium alloy comprises the following steps:

s1: preparing a raw material, namely selecting titanium or titanium alloy as the raw material, wherein the size of at least one dimension of the raw material is less than or equal to 5 mm;

s2: hydrogenation, namely, carrying out unsaturated hydrogenation treatment on the raw material in the step S1;

s3: crushing, namely performing low-temperature crushing treatment on the raw material subjected to the unsaturated hydrogenation treatment in the step S2 to obtain unsaturated titanium hydride powder;

s4: and (4) sequentially carrying out forming and sintering treatment on the unsaturated titanium hydride powder obtained in the step (S3) to obtain a titanium or titanium alloy product.

Further, in step S1, the raw material is in the form of a flat sheet, and the raw material is titanium chips, titanium alloy chips, or rolled titanium sponge sheets.

Further, in step S1, the rolled titanium sponge sheet has a thickness of 1 to 5 mm; the titanium alloy scraps are Ti-6Al-4V alloy scraps.

Further, in step S2, the hydrotreating process includes:

s2-1: vacuum pumping is carried out to 10^-3～10^-1Pa, heating to 450-550 ℃, and preserving heat for 30-60 min;

s2-2: introducing high-purity hydrogen and controlling the hydrogen absorption amount;

s2-3: and carrying out hydrogen homogenization treatment.

Further, in step S2-2, the hydrogen absorption amount is controlled to be 1.0 to 2.5 wt.%.

Further, in step S2-3, the hydrogen homogenization treatment specifically includes: after the hydrogen introduction is stopped, the temperature is raised to 550-850 ℃ again, and the temperature is kept for 2-5 h.

Further, in step S3, the cryogenic crushing treatment adopts a cryogenic mechanical crushing process, wherein the cryogenic medium is liquid argon.

Further, in step S3, the particle size of the unsaturated titanium hydride powder is 10 to 75 μm.

Further, in step S4, the forming process is performed by using a cold isostatic pressing process, wherein the pressing pressure is 150 to 200MPa, and the pressure maintaining time is 10 to 30S.

Further, in step S4, the sintering process specifically includes: and carrying out vacuum sintering densification on the blank obtained by the cold isostatic pressing forming process by adopting a sectional sintering process.

Further, the step sintering process specifically comprises the following steps:

the first section is heated to 550-750 ℃, the heating rate is 2 ℃/min, the temperature is kept for 2-10 h, and the removal of the residual hydrogen content is completed;

and heating the second section to 1150-1300 ℃, wherein the heating rate is 5 ℃/min, the sintering time is 2-5 h, and the densification is completed.

To achieve the above object, according to a second aspect of the present invention, there is provided a powder metallurgy titanium or titanium alloy article.

The titanium or titanium alloy product is prepared by the short-process preparation method of the powder metallurgy titanium or titanium alloy.

According to the invention, the flaky material is adopted to partially absorb hydrogen, the brittleness of the partially-absorbed material is utilized and the low-temperature crushing technology is combined to crush the material into powder, and then the powder is directly subjected to cold isostatic pressing forming and vacuum sintering densification to prepare the titanium and titanium alloy material, so that the dehydrogenation process is omitted.

Compared with titanium hydride powder, the powder partially absorbing hydrogen has better formability, and the problem of cracking of a large-size sintered blank is avoided; compared with hydrogenated dehydrogenated titanium powder, the hydrogenated dehydrogenated titanium powder has the advantages that the sintering density is improved, the oxygen content of a sintered blank is reduced, and the microstructure of the material is obviously refined.

Therefore, the invention realizes the short-process preparation of the powder titanium alloy product, and has the advantages of high yield, low cost and excellent product performance.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below. While exemplary embodiments of the present disclosure have been shown, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

The invention discloses a short-process preparation method of a powder metallurgy titanium or titanium alloy product, which comprises the following steps:

s1: preparing a raw material, namely selecting titanium or titanium alloy as the raw material, wherein the size of at least one dimension of the raw material is less than or equal to 5 mm; wherein: the selected raw materials are in a flat sheet shape, and the raw materials are preferably titanium chips, titanium alloy chips or rolled titanium sponge sheets; the thickness of the rolled titanium sponge sheet is 1-5 mm; the titanium alloy chips include Ti-6Al-4V alloy chips.

S2: hydrogenation, namely loading the selected raw materials into a rotary hydrogenation furnace for unsaturated hydrogenation treatment; the specific process comprises the following steps:

vacuum pumping is carried out to 10^-3～10^-1Pa, heating to 450-550 ℃, and preserving heat for 30-60 min; then high-purity hydrogen is introduced, hydrogen absorption is started, and the hydrogen absorption amount is controlled to be1.0-2.5 wt.%, and stopping introducing hydrogen when the set hydrogen absorption amount is reached; and then raising the temperature to 550-850 ℃, and preserving the heat for 2-5 hours to carry out hydrogen homogenization treatment.

S3: crushing, namely crushing the raw material subjected to the unsaturated hydrogenation treatment in the step S2 by adopting a low-temperature mechanical crushing process to obtain unsaturated titanium hydride powder; wherein the low-temperature medium is liquid argon; the particle size of the unsaturated titanium hydride powder is 10 to 75 μm.

S4: forming, namely filling the unsaturated titanium hydride powder obtained in the step S3 into a rubber sleeve, and forming by adopting a cold isostatic pressing forming process; wherein the pressing pressure is 150-200 MPa, and the pressure maintaining time is 10-30 s, so that the cold isostatic pressing blank is obtained.

S5: and sintering, namely performing vacuum sintering densification on the cold isostatic pressing blank obtained in the step S4, wherein the sintering treatment adopts a sectional sintering process, and specifically comprises the following steps: the first section is heated to 550-750 ℃, the heating rate is 2 ℃/min, the temperature is kept for 2-10 h, and the removal of the residual hydrogen content is completed; and heating the second section to 1150-1300 ℃, wherein the heating rate is 5 ℃/min, the sintering time is 2-5 h, and densification is completed to obtain the titanium or titanium alloy product.

The short-flow preparation method of the powder metallurgy titanium or titanium alloy product in the application is described in detail by specific examples.