High beta phase content ti-ta alloy with low modulus, high strength, high deformability and method of making

Abstract

The application discloses a high-beta-phase-content Ti-Ta alloy with low modulus, high strength and high deformation capacity and a preparation method thereof, and the Ti powder and the Ta powder are weighed and mixed to obtain mixed powder through low-energy ball milling; the mixed powder is pre-pressed into a shape in a mold, and then sintering densification treatment is carried out to obtain a pre-alloy block; the pre-alloy block is placed into a tube furnace to carry out solid solution treatment in a beta phase region, and then quenching treatment is carried out to obtain the high-beta-phase-content Ti-Ta alloy. The high-beta-phase-content Ti-Ta alloy has uniform phase morphology and microstructure in the microcosmic aspect, and has low modulus, high strength and high deformation capacity in the mechanical aspect; the preparation method combines powder metallurgy and heat treatment to realize diversified regulation and control of the alloy microstructure and performance, can make the Ta uniformly distributed in the alloy, and can realize uniform phase microstructure and avoid the generation of composition segregation; on this basis, the Ti-Ta alloy with rich beta phase or full beta phase is obtained through quenching and fast cooling.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of alloy materials, and particularly relates to a high-beta-phase-content Ti-Ta alloy with low modulus, high strength and high deformation capacity. BACKGROUND

[0002] Titanium alloys have the advantages of high specific strength, good room temperature performance, good corrosion resistance and good biocompatibility, and are widely used in the field of biomedical metal materials. Initially, CP-Ti and Ti6Al4V are used to replace 316L stainless steel or Co-Cr alloy containing toxic elements of Ni, Co and Cr. However, further research has found that when CP-Ti and Ti6Al4V are used as bone implant materials, the phenomenon of "stress shielding" occurs, that is, when the elastic modulus difference between the bone implant and the host bone is large, the host bone is easily damaged, and the implant fails. The elastic modulus of CP-Ti and Ti6Al4V is 110 GPa and 120 GPa, respectively, and the elastic modulus of human compact bone is about 3-30 GPa.

[0003] In addition, research has also found that although the comprehensive performance of Ti6Al4V is excellent, there are harmful elements Al and V in it, so it has become a research hotspot to find new alloys as biomedical materials. In contrast, beta titanium alloy contains almost no harmful elements, has better biocompatibility, and can maintain a low modulus while maintaining a high strength. Among them, Ta as a beta-stabilizing element of beta titanium alloy has more excellent corrosion resistance and better biocompatibility, and can achieve infinite solid solution in beta-Ti when it is a solute element of titanium alloy, and can retain beta-Ti with low elastic modulus to room temperature, which can not only play a solid solution strengthening role but also reduce the elastic modulus of titanium alloy.

[0004] At present, the process for preparing Ti-Ta alloy mainly adopts vacuum melting method, but due to the large difference in melting point and density between Ti and Ta (the melting point of Ti is 1660℃, the melting point of Ta is 2996℃, the density of Ti is 4.5g / cm 3 , and the density of Ta is 16.6g / cm 3 ), which often leads to the prepared alloy having defects such as large segregation and porosity. In order to eliminate the above defects, more than 10 times of multiple melting method needs to be adopted, which will increase the preparation cost. The powder metallurgy process has the advantages of designable organization and composition, fast sintering rate, high sintering temperature and high density, and is widely used.

[0005] A Chinese invention patent CN 104342583 A discloses a preparation method of a non-uniform tissue Ti-Ta alloy. The Ti-Ta alloy prepared by the method has obvious Ta-rich regions and Ta-rich regions due to insufficient diffusion time, and the alloy has a low elastic modulus and a high tensile strength, but has problems of high porosity and low elongation. A Chinese invention patent CN 113750288 A discloses a preparation method of a ceramic particle reinforced Ti-Ta-based bone implant composite material. Although the material has high strength, the introduction of a large amount of ceramic reinforcing phase on the basis of the Ti-Ta alloy leads to a high elastic modulus of the composite material, which limits its application in the field of biological applications. A Chinese patent CN 109732087 A discloses a Ti-Ta material with gradient change in organization to improve the low interfacial bonding strength of metal-metal-based composite materials, but the organization and performance of the material have obvious anisotropy, and the use is relatively limited. A Chinese invention patent CN 115109979 A discloses a preparation process of a Ti-Ta-Nb-Zr-Mo biomedical high-entropy alloy. The alloy has a high compressive yield strength, but has problems of high preparation cost due to a large number of added element types, difficult composition control, and multiple melting times. Zhou et al. prepared Ti-xTa alloys (x = 10-80wt.%) by vacuum melting. The research shows that when the Ta content is 30-70wt.%, the alloy has good room temperature performance (Zhou YL, Niinomi M, Akahori T, Effects of Ta content on Young's modulus and tensile properties of binary Ti-Ta alloys for biomedical applications, Materials Science and Engineering: A, 2004, 371(1-2): 283-290). Therefore, it is particularly important to prepare a Ti-Ta alloy with low elastic modulus, high strength, and high plasticity. SUMMARY

[0006] The purpose of the present application is to provide a high-beta-phase-content Ti-Ta alloy with low modulus, high strength, and high deformation capacity, which solves the problems of low strength and poor elongation of the material due to the low elastic modulus of the biomedical titanium alloy.

[0007] Another purpose of the present application is to provide a preparation method of a high-beta-phase-content Ti-Ta alloy with low modulus, high strength, and high deformation capacity, which solves the problems of easy segregation and low beta phase content caused by traditional preparation methods.

[0008] The first technical solution of the present application is: a high-beta-phase-content Ti-Ta alloy with low modulus, high strength and high deformation capacity, which is composed of the following components in percentage by mass: Ti 50-70%, Ta 30-50%, and the sum of the mass percentages of the above components is 100%.

[0009] The second technical solution of the present application is: a preparation method of a high-beta-phase-content Ti-Ta alloy with low modulus, high strength and high deformation capacity, which comprises the following steps:

[0010] Step 1: the following components are weighed in percentage by mass: Ti powder 50-70%, Ta powder 30-50%, and the sum of the mass percentages of the above components is 100%, the Ti powder and the Ta powder are mixed and low-energy ball milling is performed with a ball milling aid to obtain a mixed slurry, and then the mixed slurry is vacuum dried to obtain a Ti-Ta mixed powder;

[0011] Step 2: the Ti-Ta mixed powder obtained in step 1 is pre-pressed into a mold, and then sintering densification treatment is performed to obtain a Ti-Ta pre-alloy block;

[0012] Step 3: the Ti-Ta pre-alloy block obtained in step 2 is placed in a tube furnace for solid solution treatment in the beta phase region, and then quenching treatment is performed.

[0013] The second technical solution of the present application is characterized in that,

[0014] In step 1, the Ti powder is spherical powder with a particle size distribution range of 50-150 μm and a purity of ≥99.9%; the Ta powder is irregular powder with a particle size distribution range of 3-5 μm and a purity of ≥99.9%.

[0015] In step 1, the ball milling aid is anhydrous ethanol or isopropyl alcohol, the addition amount of the ball milling aid during low-energy ball milling is 1-2 mL, the ball-to-material ratio is 5:1, the ball milling speed is 200-250 r / min, the ball milling time is 4 h, and the milling ball is zirconia.

[0016] In step 1, the drying temperature during vacuum drying is 60℃, and the drying time is 4 h.

[0017] In step 2, sintering densification treatment is performed by using spark plasma sintering, the spark plasma sintering pressure is 30 MPa, the heating rate is 50℃ / min, the sintering temperature is 850-1400℃, the holding time is 20 min, the vacuum degree is maintained at ≤5 Pa during sintering, and the furnace is cooled to room temperature after sintering.

[0018] In step 3, the heating rate during solid solution treatment is 10℃ / min, the solid solution temperature is 1400-1600℃, the holding time is 1-2 h, and a protective gas is introduced during the solid solution treatment.

[0019] In step 3, after the holding time of the solution treatment process ends, the temperature is decreased to above the temperature point of the beta phase region at a rate of 5℃ / min, and then quenching treatment is performed.

[0020] The high-beta-phase-content Ti-Ta alloy with low modulus, high strength and high deformation capacity and the preparation method thereof have the following beneficial effects: the high-beta-phase-content Ti-Ta alloy has uniform phase morphology and composition in microstructure and has low modulus, high strength and high deformation capacity in mechanics; the preparation method can realize diversified regulation and control of the alloy structure and performance by combining powder metallurgy with heat treatment, can make Ta uniformly distributed in the alloy, and can realize uniform phase structure and avoid the generation of composition segregation; and on this basis, quenching and fast cooling obtain the Ti-Ta alloy with a large amount of beta phase or full beta phase. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is an optical metallographic micrograph, an electron micrograph and an element surface distribution diagram of the Ti-Ta alloy with uniform phase morphology and composition prepared in Example 1 of the present application;

[0022] Figure 2 is a metallographic micrograph, an electron micrograph and an element surface distribution diagram of the Ti-Ta pre-alloy block prepared in Comparative Example 1 of the present application, which has obvious Ti-rich and Ta-rich regions;

[0023] Figure 3 is a metallographic micrograph, an electron micrograph and an element surface distribution diagram of the Ti-Ta alloy prepared in Comparative Example 2 of the present application, which has uniform composition distribution;

[0024] Figure 4 is a tensile stress-strain curve and a compression stress-strain curve of the materials prepared in Example 1, Comparative Example 1 and Comparative Example 2 of the present application;

[0025] Figure 5 is an XRD spectrum of the phase characterization of the materials prepared in Example 1 and Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0026] The present application will be described in detail below in combination with the drawings and specific embodiments.

[0027] The application provides a high-beta-phase-content Ti-Ta alloy with low modulus, high strength and high deformation capacity, which is composed of the following components in percentage by mass: 50-70 wt.% of pure Ti powder, 30-50 wt.% of pure Ta powder, and the sum of the mass percentages of the two components being 100%, and the Ti-Ta pre-alloy block with high density is prepared by using the powder metallurgy process (spark plasma sintering or other hot-press sintering) after the low-energy mixing, and then the Ti-Ta alloy with a large amount or full beta phase structure is obtained by using the long-time interdiffusion process and quenching fast cooling process in the beta phase region, so that the alloy is further homogenized in the organization and composition, and has the characteristics of homogenization in the organization and element distribution, and has the excellent performance of low modulus, high strength and high deformation capacity in the mechanical properties.

[0028] The application also provides a preparation method of the high-beta-phase-content Ti-Ta alloy with low modulus, high strength and high deformation capacity, which is specifically carried out according to the following steps:

[0029] Step 1: 50-70 wt.% of pure Ti powder and 30-50 wt.% of pure Ta powder are respectively weighed according to the percentage by mass, the sum of the mass percentages of the components is 100%, the pure Ti powder and the pure Ta powder are subjected to low-energy ball milling, the ball milling aid is anhydrous ethanol or isopropyl alcohol, the mixed slurry is obtained, and then the mixed slurry is subjected to vacuum drying to obtain the mixed and uniform Ti-Ta mixed powder. The pure Ti powder is spherical powder, the powder particle size distribution range is 50-150 μm, and the purity is greater than or equal to 99.9%; the pure Ta powder is irregular powder, the powder particle size distribution range is 3-5 μm, and the purity is greater than or equal to 99.9%; the addition amount of the ball milling aid in the low-energy ball milling process is 1-2 mL, the ball-to-material ratio is 5:1, the ball milling speed is 200-250 r / min, the ball milling time is 4 h, and the grinding ball is zirconium oxide; the drying temperature in the vacuum drying is 60 ℃, and the drying time is 4 h.

[0030] Step 2: the mixed powder obtained in step 1 is pre-pressed into a graphite mold, and is subjected to sintering densification treatment by using the spark plasma sintering or other hot-press sintering process to obtain the pre-alloy block with the macroscopically uniform Ta powder distribution and the close combination of the Ti powder particles. The spark plasma sintering pressure is 30 MPa, the temperature rising speed is 50 ℃ / min, the sintering temperature is 850-1400 ℃, the holding time is 20 min, the vacuum degree is kept to be less than or equal to 5 Pa during the sintering process, and the sintering is completed and then the furnace is cooled to room temperature.

[0031] Step 3: The Ti-Ta pre-alloyed block obtained in Step 2 is placed in a tube furnace for homogenization treatment. Under the premise of sufficient Ta particle solidification, after quenching, a Ti-Ta alloy with homogenization on both macroscopic and microscopic scales and rich in a large amount of β phase is obtained. This alloy also has excellent mechanical properties such as low modulus, high strength, and high deformability. The solution treatment process involves a heating rate of 10℃ / min, a solution temperature of 1400~1600℃, a holding time of 1~2h, and argon gas is introduced as a protective gas during the heat treatment. After the holding time is completed, the temperature is reduced to 1000℃ (or above the temperature point of other β phase regions) at a cooling rate of 5℃ / min. The sample is then quickly placed in ice water for quenching treatment.

[0032] Through the above methods, the present invention provides a low-modulus, high-strength, and high-deformability Ti-Ta alloy with high β-phase content and its preparation method. Addressing the problem of segregation easily caused by traditional methods when preparing alloys with large density and melting point differences, this invention proposes a design approach combining powder metallurgy sintering with subsequent heat treatment control. Using pre-prepared alloy component powders as raw materials, the raw material powders are uniformly mixed through a suitable low-energy ball milling process. Then, a rapid sintering process using spark plasma sintering (or other hot-pressing sintering methods) is employed to prepare a high-density pre-alloyed bulk. Subsequently, the alloy microstructure and morphology can be controlled according to the desired properties using appropriate heat treatment processes. This preparation process combining powder metallurgy and heat treatment allows for diversified control of the alloy microstructure and properties, further homogenizing the alloy's microstructure and composition. Based on this, rapid quenching and cooling yields a Ti-Ta alloy rich in a large amount of β-phase or all β-phase, resulting in a titanium alloy with low modulus, high strength, and high elongation.

[0033] Comparative Example 1

[0034] As a comparative example 1 of the present invention, a Ti-Ta pre-alloyed bulk material with macroscopically uniform and microscopically non-uniform distribution of Ti powder particles and Ta powder particles was prepared by spark plasma sintering, specifically according to the following steps:

[0035] Step 1: pure Ti powder 50wt.%, pure Ta powder 50wt.% are weighed according to the mass percentage, the sum of the mass percentages of the above components is 100%, the pure Ti powder and the pure Ta powder are low-energy ball milled, the ball milling aid is anhydrous ethanol, the mixed slurry is obtained, and then the mixed slurry is vacuum dried to obtain a mixed uniform Ti, Ta mixed powder. Among them: the pure Ti powder is spherical powder, the powder particle size distribution range is 50-150 μm, the purity is ≥99.9%; the pure Ta powder is irregular powder, the powder particle size distribution range is 3-5 μm, the purity is ≥99.9%; the addition amount of the ball milling aid in the low-energy ball milling process is 1-2 mL, the ball-to-material ratio is 5:1, the ball milling speed is 200-250 r / min; the ball milling time is 4 h, and the grinding ball is zirconium oxide; the drying temperature during vacuum drying is 60°C, and the drying time is 4 h.

[0036] Step 2: the mixed powder obtained in step 1 is pre-pressed into a graphite mold, and sintered and densified by spark plasma sintering to obtain a pre-alloy block with uniform macroscopic distribution of Ta powder and tight combination with Ti powder particles. Among them: the pressure of spark plasma sintering in step 2 is 30 MPa, the heating rate is 50°C / min, the sintering temperature is 850-1400°C, the holding time is 20 min, the vacuum degree is maintained ≤5 Pa during sintering, and the sintering is cooled to room temperature in the furnace after sintering.

[0037] Comparative Example 2

[0038] As Comparative Example 2 of the present application, a Ti-Ta alloy with uniform alloy composition and a large amount of martensite phase is prepared by spark plasma sintering combined with heat treatment, which is specifically implemented according to the following steps:

[0039] Step 1: pure Ti powder 50wt.%, pure Ta powder 50wt.% are weighed according to the mass percentage, the sum of the mass percentages of the above components is 100%, the pure Ti powder and the pure Ta powder are low-energy ball milled, the ball milling aid is anhydrous ethanol or isopropanol, the mixed slurry is obtained, and then the mixed slurry is vacuum dried to obtain a mixed uniform Ti, Ta mixed powder. Among them: the pure Ti powder is spherical powder, the powder particle size distribution range is 50-150 μm, the purity is ≥99.9%; the pure Ta powder is irregular powder, the powder particle size distribution range is 3-5 μm, the purity is ≥99.9%; the addition amount of the ball milling aid in the low-energy ball milling process is 1-2 mL, the ball-to-material ratio is 5:1, the ball milling speed is 200-250 r / min; the ball milling time is 4 h, and the grinding ball is zirconium oxide; the drying temperature during vacuum drying is 60°C, and the drying time is 4 h.

[0040] Step 2: The mixed powder obtained in step 1 is pre-pressed into a graphite mold, and sintered and densified by using a spark plasma sintering to obtain a pre-alloy block with uniformly distributed Ta powder and tightly combined with Ti powder particles. The pressure of the spark plasma sintering is 30 MPa, the heating rate is 50 ℃ / min, the sintering temperature is 850-1400 ℃, the holding time is 20 min, the vacuum degree is kept ≤5 Pa during the sintering process, and the sintering is cooled to room temperature in the furnace after completion.

[0041] Step 3: The Ti-Ta alloy obtained in step 2 is placed in a tube furnace for homogenization treatment, and the Ti-Ta alloy with uniform macro-scale and micro-scale is obtained after the furnace is cooled to room temperature under the premise of fully solid-solution of Ta particles. The heating rate in the solid solution treatment is 10 ℃ / min, the solid solution temperature is 1600 ℃, the holding time is 1 h, argon gas is introduced as a protective gas during the heat treatment process, and the furnace cooling rate is 5 ℃ / min.

[0042] Example 1

[0043] The preparation method of the high-beta-phase-content Ti-Ta alloy with low modulus, high strength and high deformation capacity according to the present application is implemented according to the following steps:

[0044] Step 1: 50wt.% of pure Ti powder and 50wt.% of pure Ta powder are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%. The pure Ti powder and the pure Ta powder are subjected to low-energy ball milling, and anhydrous ethanol is used as a ball milling aid. After obtaining the mixed slurry, the mixed slurry is subjected to vacuum drying to obtain Ti and Ta mixed powder with uniform mixing. The pure Ti powder is spherical powder with a particle size distribution range of 50-150 μm and a purity of ≥99.9%; the pure Ta powder is irregular powder with a particle size distribution range of 3-5 μm and a purity of ≥99.9%; the addition amount of the ball milling aid during the low-energy ball milling process is 1-2 mL, the ball-to-material ratio is 5:1, the ball milling speed is 200-250 r / min; the ball milling time is 4 h, and the grinding ball is zirconia; the drying temperature during the vacuum drying is 60 ℃, and the drying time is 4 h.

[0045] Step 2: The mixed powder obtained in step 1 is pre-pressed into a graphite mold, and sintered and densified by using a spark plasma sintering to obtain a pre-alloy block with uniformly distributed Ta powder and tightly combined with Ti powder particles. The pressure of the spark plasma sintering is 30 MPa, the heating rate is 50 ℃ / min, the sintering temperature is 850 ℃, the holding time is 20 min, the vacuum degree is kept ≤5 Pa during the sintering process, and the sintering is cooled to room temperature in the furnace after completion.

[0046] Step 3: Put the Ti-Ta alloy obtained in step 2 into a tube furnace for homogenization treatment, and under the premise that the Ta particles are fully solid-solved, the Ti-Ta alloy with uniform macro-scale and micro-scale and rich in a large amount of β phase is obtained after quenching, and the alloy has excellent mechanical properties of low modulus, high strength and high deformation capacity. In the solid solution treatment, the heating rate is 10℃ / min, the solid solution temperature is 1600℃, the holding time is 1h, and argon is introduced as a protective gas during the heat treatment process. In order to ensure the safety of operation, after the holding time ends, the temperature is reduced to 1000℃ (or other temperature points above the β phase region) at a rate of 5℃ / min, and the sample is quickly placed in ice water for quenching treatment.

[0047] Example 2

[0048] The preparation method of the high-β-phase-content Ti-Ta alloy with low modulus, high strength and high deformation capacity of the application is implemented according to the following steps:

[0049] Step 1: Take pure Ti powder 50wt.% and pure Ta powder 50wt.% according to the mass percentage, and the sum of the mass percentages of the above components is 100%, and the pure Ti powder and the pure Ta powder are low-energy ball milled, the ball milling aid is anhydrous ethanol, the mixed slurry is obtained, and then the mixed slurry is vacuum dried to obtain the mixed uniform Ti, Ta mixed powder. Among them: the pure Ti powder is spherical powder, the powder particle size distribution range is 50-150μm, the purity is ≥99.9%; the pure Ta powder is irregular powder, the powder particle size distribution range is 3-5μm, the purity is ≥99.9%; the addition amount of ball milling aid in the low-energy ball milling process is 1-2mL, the ball-to-material ratio is 5:1, and the ball milling speed is 200-250r / min; the ball milling time is 4h, and the grinding ball is zirconia; the drying temperature during vacuum drying is 60℃, and the drying time is 4h.

[0050] Step 2: The mixed powder obtained in step 1 is pre-pressed into a graphite mold, and sintered and densified by spark plasma sintering to obtain a Ti-Ta alloy containing a large amount of martensite phase and uniform composition and organization. Among them: the spark plasma sintering pressure is 30MPa, the heating rate is 50℃ / min, the sintering temperature is 1400℃, the holding time is 20min, the vacuum degree is maintained ≤5Pa during sintering, and the sintering is cooled to room temperature after sintering.

[0051] Step 3: The Ti-Ta alloy obtained in step 2 is placed in a tube furnace for solid solution treatment, and after quenching, a Ti-Ta alloy with macro-scale and micro-scale homogenization and rich in a large amount of β phase is obtained, and the alloy has excellent mechanical properties of low modulus, high strength and high deformation capacity. Among them: the heating rate in the solid solution treatment is 10℃ / min, the solid solution temperature is 1500℃, the holding time is 1.5h, argon is introduced as a protective gas during the heat treatment process, and after the holding time is over, the sample is quickly placed in ice water for quenching treatment.

[0052] Example 3

[0053] The preparation method of the low modulus, high strength and high deformation capacity high β phase content Ti-Ta alloy of the application is implemented according to the following steps:

[0054] Step 1: The pure Ti powder 70wt.% and the pure Ta powder 30wt.% are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%, the pure Ti powder and the pure Ta powder are low-energy ball milled, the ball milling aid is anhydrous ethanol, the mixed slurry is obtained, and the mixed slurry is vacuum dried to obtain the mixed uniform Ti and Ta mixed powder. Among them: the pure Ti powder is a spherical powder, the powder particle size distribution range is 50-150μm, the purity is ≥99.9%; the pure Ta powder is irregular powder, the powder particle size distribution range is 3-5μm, the purity is ≥99.9%; the addition amount of the ball milling aid in the low-energy ball milling process is 1-2mL, the ball-to-material ratio is 5:1, the ball milling speed is 200-250r / min; the ball milling time is 4h, and the grinding ball is zirconia; the drying temperature during vacuum drying is 60℃, and the drying time is 4h.

[0055] Step 2: The mixed powder obtained in step 1 is pre-pressed into a graphite mold, and sintered and densified by spark plasma sintering to obtain a pre-alloy block with uniform macroscopic distribution of Ta powder and tight combination with Ti powder particles. Among them: the spark plasma sintering pressure is 30MPa, the heating rate is 50℃ / min, the sintering temperature is 850℃, the holding time is 20min, the vacuum degree is maintained ≤5Pa during sintering, and the sintering is cooled to room temperature after sintering.

[0056] Step 3: Put the Ti-Ta alloy obtained in step 2 into a tube furnace for homogenization treatment, and under the premise that the Ta particles are fully solid-solved, a Ti-Ta alloy with uniform macro-scale and micro-scale and rich in a large amount of β phase is obtained after quenching, and the alloy has excellent mechanical properties of low modulus, high strength and high deformation capacity. In the solid solution treatment, the heating rate is 10℃ / min, the solid solution temperature is 1400℃, the holding time is 2h, and argon is introduced as a protective gas during the heat treatment process. To ensure safety, the sample is quickly placed in ice water to quench at a cooling rate of 5℃ / min to 1000℃ (or other β phase zone temperature points above) after the holding time ends.

[0057] Example 4

[0058] The preparation method of the high β phase content Ti-Ta alloy with low modulus, high strength and high deformation capacity of the application is implemented according to the following steps:

[0059] Step 1: The pure Ti powder is 60wt.%, and the pure Ta powder is 40wt.%, and the sum of the mass percentages of the above components is 100%. The pure Ti powder and the pure Ta powder are low-energy ball milled, the ball milling aid is anhydrous ethanol, the mixed slurry is obtained, and the mixed slurry is vacuum dried to obtain a mixed uniform Ti, Ta mixed powder. Among them: the pure Ti powder is a spherical powder, the powder particle size distribution range is 50-150μm, the purity is ≥99.9%; the pure Ta powder is irregular powder, the powder particle size distribution range is 3-5μm, the purity is ≥99.9%; the addition amount of the ball milling aid in the low-energy ball milling process is 1-2mL, the ball-to-material ratio is 5:1, and the ball milling speed is 200-250r / min; the ball milling time is 4h, and the grinding ball is zirconia; the drying temperature during vacuum drying is 60℃, and the drying time is 4h.

[0060] Step 2: The mixed powder obtained in step 1 is pre-pressed into a graphite mold, and vacuum hot-pressing sintering is used for sintering densification treatment to obtain a pre-alloy block with uniformly distributed Ta powder and tightly combined with Ti powder particles. Among them: the sintering pressure in the hot-pressing sintering is 30MPa, the heating rate is 50℃ / min, the sintering temperature is 1000℃, the holding time is 20min, the vacuum degree is maintained ≤5Pa during sintering, and the sample is cooled to room temperature after sintering.

[0061] Step 3: Put the Ti-Ta alloy obtained in step 2 into a tube furnace for homogenization treatment. Under the premise that the Ta particles are fully solid-solved, the Ti-Ta alloy with homogeneous macro-scale and micro-scale and rich in a large number of β phases is obtained after quenching, and the alloy has excellent mechanical properties of low modulus, high strength and high deformation capacity. In the solid solution treatment, the heating rate is 10℃ / min, the solid solution temperature is 1600℃, and the holding time is 1h. In the heat treatment process, argon is introduced as a protective gas. In order to ensure the safety of operation, after the holding time ends, the sample is rapidly placed into ice water to quench at a cooling rate of 5℃ / min to 1000℃ (or other β phase zone temperature points above).

[0062] Result analysis

[0063] 1) Figure 1 (a), Figure 1 (b), Figure 1 (c), Figure 1 (d) are, in turn, optical metallographic micrographs, electron micrographs, Ti element surface distribution maps and Ta element surface distribution maps of the Ti-Ta alloy with uniform phase morphology and organizational composition prepared in Example 1. It can be seen from Figure 1 that Ta is completely solid-solved in Ti, the Ti-Ta alloy material has uniform organizational composition, and the phase organization is almost composed of full β-Ti, containing a small amount of α"martensite phase, and the distribution is uniform.

[0064] 2) Figure 2 (a), Figure 2 (b), Figure 2 (c), Figure 2 (d) are, in turn, metallographic micrographs, electron micrographs, Ti element surface distribution maps and Ta element surface distribution maps of the Ti-Ta pre-alloy block with obvious Ti-rich and Ta-rich regions prepared in Comparative Example 1. It can be seen from Figure 2 that there is a diffusion layer between the Ti-rich and Ta-rich regions, which is due to the limited interdiffusion distance between Ti and Ta at a lower sintering temperature, but the preparation process can ensure that the Ti and Ta particles have good metallurgical bonding and high density.

[0065] 3) Figure 3 (a), Figure 3 (b), Figure 3 (c), Figure 3 (d) are, in turn, metallographic micrographs, electron micrographs, Ti element surface distribution maps and Ta element surface distribution maps of the Ti-Ta alloy with uniform distribution of organizational composition prepared in Comparative Example 2. It can be seen from Figure 3It can be seen that the alloy phase structure and the composition uniformity are high. Since Ta is a β-Ti isomeric β-stabilizing element, its stability to β phase is weak, and the cooling method of furnace cooling cannot effectively keep a large amount of β phase at room temperature. Because a large amount of Ta is completely solid-solved in Ti, the phase transition of β-Ti to α-Ti can be prevented to a certain extent, so that the alloy is composed of intermediate-state martensite phase.

[0066] 4) The titanium alloy-based composite material with micro-structure has excellent mechanical properties, and has high strength and high deformation capacity while having low modulus. Figure 4 (a)、 Figure 4 (b) are the tensile stress-strain curves of the materials prepared in Example 1 and Comparative Example 1, and the compression stress-strain curves of the materials prepared in Example 1 and Comparative Example 2. It can be seen by comparison that the maximum tensile strength of the Ti-Ta alloy with uniform structure and containing a large amount of β phase is 1072 MPa, and the elongation is 12%. The Ti-Ta pre-alloy block with macroscopic uniformity and microscopic non-uniformity has low sintering temperature, short Ti-Ta diffusion distance, and limited metallurgical bonding degree, so that the strength and elongation are low. Through room temperature compression test of Example 1 and Comparative Example 2, it can be seen that due to the large amount of needle-like martensite phase contained in Comparative Example 2, the material has high compression yield strength but poor plasticity, which is manifested as low compression rate of the material. The Example 1 treated by homogenization and then fast cooling has more excellent compression rate without losing too much strength. This is because the Ti-Ta alloy after quenching retains more β phase with better plastic deformation ability, so that the alloy prepared in Example 1 has better compression rate.

[0067] 5) Figure 5 The phase characterization results of Example 1 and Comparative Example 1 are shown in Table 1. In Comparative Example 1, due to the short sintering time, the diffusion of Ti and Ta is not sufficient, and the microstructure of the pre-alloy block is mainly composed of α phase and pure Ta phase. Compared with Comparative Example 1, the Ti and Ta in Example 1 realize uniform interdiffusion, and all the β phase can be retained at room temperature by using fast cooling technology.

[0068] Table 1 Comparison of elastic modulus of commercial TC4, comparative examples and examples

[0069] TC4 Comparative Example 2 Example 1 Elastic Modulus / GPa 120 115(±2) 94(±5)

[0070] 6) Table 1 is the comparison of elastic modulus of commercial TC4, comparative example 2 and example 1. The order of elastic modulus from high to low in each phase structure of titanium alloy is: w > a > a' > a" > b. The elastic modulus of comparative example 2 in the application is similar to that of TC4, while in example 1, the elastic modulus of the material is reduced due to the full diffusion of Ti and Ta and the rapid cooling process, so that a large amount of b phase is retained at room temperature.

Claims

1. A method for producing a high beta phase content Ti-Ta alloy with low modulus, high strength, and high deformability, characterized in that, The method comprises the following steps: Step 1: the following components are weighed according to the mass percentage: Ti powder 50-70 %, Ta powder 30-50 %, the sum of the mass percentages of the above components is 100 %, the Ti powder and the Ta powder are mixed and added with a ball milling aid to obtain a mixed slurry by low-energy ball milling, and then the mixed slurry is vacuum dried to obtain a Ti-Ta mixed powder; Step 2: the Ti-Ta mixed powder obtained in step 1 is pre-pressed into a shape in a mold, and then sintered and densified by spark plasma sintering, the spark plasma sintering pressure is 30 MPa, the heating rate is 50 ℃ / min, the sintering temperature is 850-1400 ℃, the holding time is 20 min, the vacuum degree is kept ≤5 Pa during the sintering process, and the sintering is completed by cooling to room temperature in the furnace, thereby obtaining a Ti-Ta pre-alloy bulk body; Step 3: the Ti-Ta pre-alloy bulk body obtained in step 2 is placed in a tube furnace for solid solution treatment in the β phase region, the heating rate is 10 ℃ / min, the solid solution temperature is 1400-1600 ℃, the holding time is 1-2 h, a protective gas is introduced during the solid solution treatment, and then quenching treatment is performed.

2. The method for preparing a low-modulus, high-strength, and high-deformability Ti-Ta alloy with high β-phase content as described in claim 1, characterized in that, In step 1, the Ti powder is a spherical powder, the powder particle size distribution range is 50-150 μm, and the purity is ≥99.9 %; the Ta powder is an irregular powder, the powder particle size distribution range is 3-5 μm, and the purity is ≥99.9 %.

3. The method for preparing a low-modulus, high-strength, and high-deformability Ti-Ta alloy with high β-phase content as described in claim 1, characterized in that, In step 1, the ball milling aid is anhydrous ethanol or isopropyl alcohol, the addition amount of the ball milling aid during the low-energy ball milling process is 1-2 mL, the ball-to-material ratio is 5:1, the ball milling speed is 200-250 r / min, the ball milling time is 4 h, and the milling ball is zirconium oxide.

4. The method of claim 1, wherein the high beta phase content Ti-Ta alloy having low modulus, high strength, and high deformability is characterized by, In step 1, the drying temperature during the vacuum drying is 60 ℃, and the drying time is 4 h.

5. The method of claim 1, wherein the high beta phase content Ti-Ta alloy having low modulus, high strength, and high deformability is characterized by: In step 3, after the holding time of the solid solution treatment process ends, the temperature is lowered to above the β phase region temperature point at a rate of 5 ℃ / min, and then quenching treatment is performed.

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