A high-density high-strength plastic tantalum-niobium-zirconium multi-phase alloy and a preparation method thereof

Abstract

This invention relates to a high-density, high-strength, and ductile TaNbZr multiphase alloy and its preparation method, belonging to the field of alloy technology. The alloy consists of a Ta phase, a TaNb solid solution phase, and a NbZr solid solution phase. Through multiphase structure design, high density, high strength, and good ductility are synergistically optimized. The preparation method employs a powder metallurgy process of stepwise ball milling and pressure-driven rapid sintering. First, stepwise ball milling disperses excess Ta into different phases, reducing the modulus mismatch caused by Ta and avoiding the formation of brittle phases such as TaZr. Second, pressure-driven rapid sintering achieves good material density, and increasing the heating rate and shortening the holding time reduces elemental diffusion. Finally, a refractory high-entropy TaNbZr alloy with excellent mechanical properties is obtained.

Description

Technical Field

[0001] This invention relates to a high-density, high-strength, and ductile TaNbZr multiphase alloy and its preparation method, belonging to the field of alloy technology. Background Technology

[0002] TaNbZr alloys possess high density, good strength and toughness, and high-temperature strength, thus showing promising application prospects in fields such as high-temperature aerospace components and warhead damage elements. However, the densities of currently reported TaNbZr alloys are generally below 11 g / cm³, making it difficult to meet the requirements of applications with higher material density. To further increase the alloy density, it is necessary to increase the Ta content, but traditional smelting processes face significant technical bottlenecks in preparing high-Ta-content TaNbZr alloys: On the one hand, Ta has an extremely high melting point, and as its content increases, the overall melting point of the alloy rises significantly. Unmelted high-melting-point phases are prone to appear during the smelting process, and severe compositional segregation occurs. Subsequent homogenization requires long-term holding at temperatures above 1300℃, which not only places stringent demands on equipment but also exacerbates material oxidation, leading to a sharp increase in the difficulty of alloy preparation. On the other hand, the elastic modulus of Ta differs significantly from that of Nb and Zr. High Ta content exacerbates the modulus mismatch problem, resulting in alloy embrittlement and a significant decrease in plasticity, failing to meet the requirements of practical applications for material strength and toughness. For example, Shen et al. (Shen et al., 2024, Journal of Alloys and Compounds In TiZrTa x In NbMo refractory high-entropy alloys, it was found that as the Ta content increased, the lattice mismatch of the alloy increased from 0.67% to 1.21%, and the room temperature compressive plasticity decreased significantly from 34.8% to 9.1%. This indicates that the modulus mismatch caused by high Ta content is an important reason for the decrease in plasticity.

[0003] To overcome the common problems of uneven melting and component segregation in smelting processes, powder metallurgy has become an effective approach for preparing high-melting-point alloys. Powder metallurgy typically involves mechanically mixing metal powders and then shaping and sintering them to prepare metallic materials, composite materials, and various products. Currently, in the powder metallurgy preparation of refractory alloys, prolonged ball milling is often used to alloy the powders, combined with extended holding times to achieve higher density. However, this process is not suitable for TaNbZr alloys with high Ta content. Prolonged ball milling not only fails to solve the intrinsic brittleness problem caused by modulus mismatch but also easily introduces excessive impurities (such as C, N, and O), worsening the material's plasticity. Simultaneously, while longer sintering holding times are required to increase density, this further promotes element diffusion, exacerbating the modulus mismatch problem, making intrinsic brittleness more pronounced, and severely deteriorating the alloy's mechanical properties. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a high-density, high-strength, and ductile TaNbZr multiphase alloy and its preparation method. The alloy consists of a Ta phase, a TaNb solid solution phase, and a NbZr solid solution phase. Through multiphase structure design, high density, high strength, and good ductility are synergistically optimized. The preparation method employs a powder metallurgy process of stepwise ball milling and pressure-driven rapid sintering. First, stepwise ball milling disperses excess Ta into different phases, reducing the modulus mismatch caused by Ta and avoiding the formation of brittle phases such as TaZr. Second, pressure-driven rapid sintering achieves good material density, and increasing the heating rate and shortening the holding time reduces elemental diffusion. Finally, a refractory high-entropy TaNbZr alloy with excellent mechanical properties is obtained.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows.

[0006] A high-density, high-strength, and ductile TaNbZr multiphase alloy is disclosed, comprising uniformly distributed Ta phase, TaNb solid solution phase, and NbZr solid solution phase; wherein, based on the total molar amount of Ta phase, TaNb solid solution phase, and NbZr solid solution phase as 100%, the molar percentage of Ta phase is 30%~50%, the molar percentage of TaNb solid solution phase is 20%~50%, and the molar percentage of NbZr solid solution phase is 10%~30%.

[0007] The atomic ratio of Ta in the TaNb solid solution phase is 35%~65%; the atomic ratio of Zr in the NbZr solid solution phase is 40%~90%. The density of the multiphase alloy is greater than 11 g / cm³. 3 Dynamic compressive strength ≥1700 MPa, fracture strain ≥40%.

[0008] Preferably, the TaNb solid solution phase has a BCC structure, and the atomic ratio of Ta is 40%~60%.

[0009] Preferably, the NbZr solid solution phase has a BCC structure, and the atomic ratio of Zr is 50%~80%.

[0010] A method for preparing a high-density, high-strength, and ductile TaNbZr multiphase alloy according to the present invention, comprising the following steps: (1) Weigh out tantalum powder, niobium powder and zirconium hydride powder according to the proportion of each element in the multiphase alloy; (2) Weigh out a portion of tantalum powder and niobium powder according to the proportion and composition of the TaNb solid solution phase in the multiphase alloy, mix them and ball mill them to obtain TaNb alloy powder with uniform composition. The remaining niobium powder and zirconium hydride powder were mixed and ball-milled to obtain NbZr alloy powder with uniform composition. The remaining tantalum powder was mixed with TaNb alloy powder and NbZr alloy powder and then ball-milled to obtain a uniformly mixed composite alloy powder. (3) The composite alloy powder is loaded into a graphite mold, placed in a sintering furnace, and vacuumed. First, the temperature is raised to 850~950 ℃ at a heating rate of 70 ℃ / min or higher, and sintered at that temperature for 3~5 min. Then, the temperature is raised to 1150~1300 ℃ at a heating rate of 50 ℃ / min or higher, and pressure is applied to 60~110 MPa. Sintering is carried out at that temperature and pressure for 10~20 min. After the holding period, a high-density, high-strength, and ductile TaNbZr multiphase alloy is obtained.

[0011] Preferably, in step (1), the purity of the tantalum powder, niobium powder and zirconium hydride powder is ≥95% and the particle size is 30~50 μm.

[0012] Preferably, in step (2), the ball milling speed is 200~400 r / min, the ball-to-material ratio is 5:1~10:1, the ball milling time for preparing TaNb alloy powder and NbZr alloy powder is 20~30 h, and the ball milling time for preparing composite alloy powder is 2~5 h.

[0013] Preferably, in step (3), a metal foil with a temperature 200°C or lower than the sintering temperature is placed inside the graphite mold, and the thickness of the metal foil is less than or equal to 0.05 mm. The metal foil includes tantalum foil, zirconium foil, and titanium foil.

[0014] Preferably, in step (3), the temperature is increased to 850-950 ℃ at a heating rate of 70-90 ℃ / min.

[0015] Preferably, in step (3), the temperature is increased to 1150~1300 ℃ at a heating rate of 50~100 ℃ / min.

[0016] Preferably, in step (3), the pressure is increased to 70~100 MPa.

[0017] Beneficial effects This invention provides a high-density, high-strength, and ductile TaNbZr multiphase alloy, which is composed of uniformly distributed Ta phase, TaNb solid solution phase, and NbZr solid solution phase. By controlling the composition and proportion of each phase, the Ta phase provides the alloy with ductile load-bearing capacity; the TaNb phase enhances the alloy strength through solid solution strengthening; and the NbZr solid solution phase balances strength and deformation capacity. The synergistic effect of the three-phase structure effectively alleviates the modulus mismatch problem caused by high Ta content, achieving synergistic optimization of high density, high strength, and good ductility.

[0018] This invention provides a method for preparing a high-density, high-strength, and ductile TaNbZr multiphase alloy. First, TaNb alloy powder and NbZr alloy powder are obtained separately through stepwise ball milling. Then, they are mixed with tantalum powder through ball milling to obtain a composite alloy powder. The distributed ball milling method also reduces the introduction of impurity elements. Finally, rapid hot-pressing sintering is performed, ensuring high pressure during the sintering process to reduce defects in the material, increase density, and achieve a material density close to the theoretical density. Simultaneously, a high heating rate and short holding time are used during sintering to reduce the diffusion time of each element in the material, allowing the three phases to be completely retained, ultimately giving the alloy both good strength and toughness.

[0019] The method described in this invention employs powder metallurgy, eliminating the need for high-temperature, long-term homogenization treatment. This avoids the oxidation risks and equipment limitations associated with smelting processes, making the preparation process easier to control and suitable for industrial production. The resulting alloy possesses high density, high strength and plasticity, as well as good corrosion resistance and high-temperature resistance, making it widely applicable in aerospace, nuclear industry, medical, and high-efficiency destruction fields. Attached Figure Description

[0020] Figure 1 This is a microstructure diagram of the multiphase alloy described in Example 1 of the present invention. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to specific embodiments.

[0022] A high-density, high-strength, and ductile TaNbZr multiphase alloy is disclosed, comprising uniformly distributed Ta phase, TaNb solid solution phase, and NbZr solid solution phase. The total molar percentage of the Ta phase, TaNb solid solution phase, and NbZr solid solution phase is 100%, with the Ta phase comprising 30%–50% (e.g., 30%, 35%, 40%, 45%, 50%), the TaNb solid solution phase comprising 20%–50% (e.g., 20%, 25%, 30%, 35%, 40%, 45%, 50%), and the NbZr solid solution phase comprising 10%–30% (e.g., 10%, 12%, 15%, 28%, 20%, 23%, 25%, 27%, 30%). The atomic ratio of Ta in the TaNb solid solution phase is 35%~65% (e.g., 35%, 40%, 45%, 50%, 55%, 60%, 65%); the atomic ratio of Zr in the NbZr solid solution phase is 40%~90% (e.g., 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%). The density of the multiphase alloy is greater than 11 g / cm³. 3 Dynamic compressive strength ≥1700 MPa, fracture strain ≥40%.

[0023] In some embodiments, the TaNb solid solution phase has a BCC structure, and the atomic ratio of Ta is 40% to 60% (e.g., 40%, 43%, 45%, 47%, 50%, 55%, 60%).

[0024] In some embodiments, the NbZr solid solution phase has a BCC structure, and the atomic ratio of Zr is 50% to 80% (e.g., 50%, 55%, 60%, 65%, 70%, 75%, 80%).

[0025] A method for preparing a high-density, high-strength, and ductile TaNbZr multiphase alloy according to the present invention, comprising the following steps: (1) Weigh out tantalum powder, niobium powder and zirconium hydride powder according to the proportion of each element in the multiphase alloy; (2) Weigh out a portion of tantalum powder and niobium powder according to the proportion and composition of the TaNb solid solution phase in the multiphase alloy, mix them and ball mill them to obtain TaNb alloy powder with uniform composition. The remaining niobium powder and zirconium hydride powder were mixed and ball-milled to obtain NbZr alloy powder with uniform composition. The remaining tantalum powder was mixed with TaNb alloy powder and NbZr alloy powder and then ball-milled to obtain a uniformly mixed composite alloy powder. (3) The composite alloy powder is loaded into a graphite mold, placed in a sintering furnace, and vacuumed. First, the temperature is raised to 850~950℃ (e.g., 850℃, 860℃, 870℃, 880℃, 890℃, 900℃, 910℃, 920℃, 930℃, 940℃, 950℃) at a rate of 70℃ / min or higher (e.g., 70℃ / min, 75℃ / min, 80℃ / min, 85℃ / min, 90℃ / min), and held at this temperature for 3~5 min (e.g., 3 min, 4 min, 5 min). Then, the temperature is raised to 50℃ / min or higher (e.g., 50℃ / min, 55℃ / min, 60℃ / min, 65℃ / min, 70℃ / min, 75℃ / min, 80℃ / min, 85 ... The temperature was increased to 1150~1300 ℃ (e.g., 1150 ℃, 1200 ℃, 1250 ℃, 1300 ℃) at a heating rate of ℃ / min, 90 ℃ / min, 100 ℃ / min, and pressurized to 60~110 MPa (e.g., 60 MPa, 65 MPa, 70 MPa, 75 MPa, 80 MPa, 85 MPa, 90 MPa, 95 MPa, 100 MPa, 110 MPa), and sintered under heat and pressure for 10~20 min (e.g., 10 min, 13 min, 15 min, 17 min, 19 min, 20 min). After the heat holding period, a high-density, high-strength, and ductile TaNbZr multiphase alloy was obtained.

[0026] In some embodiments, in step (1), the tantalum powder, niobium powder and zirconium hydride powder have a purity of ≥95% and a particle size of 30~50 μm.

[0027] In some embodiments, in step (2), the ball milling speed is 200~400 r / min (e.g., 200 r / min, 300 r / min, 400 r / min), and the ball-to-material ratio is 5:1~10:1 (e.g., 5:1, 6:1, 7:1, 8:1, 9:1, 10:1); the ball milling time for preparing TaNb alloy powder and NbZr alloy powder is 20~30 h (e.g., 20 h, 22 h, 26 h, 28 h, 30 h); and the ball milling time for preparing composite alloy powder is 2~5 h (e.g., 2 h, 3 h, 4 h, 5 h).

[0028] In some embodiments, in step (3), a metal foil with a temperature 200°C or higher than the sintering temperature is placed inside the graphite mold, and the thickness of the metal foil is less than or equal to 0.05 mm. The metal foil includes tantalum foil, zirconium foil, and titanium foil.

[0029] In some embodiments, in step (3), the temperature is increased to 850-950 ℃ at a heating rate of 70-90 ℃ / min.

[0030] In some embodiments, in step (3), the temperature is increased to 1150-1300 ℃ at a heating rate of 50-100 ℃ / min.

[0031] In some embodiments, in step (3), the pressure is increased to 70~100 MPa.

[0032] Example 1 A Ta 50 Nb 34 Zr 16 A method for preparing multiphase alloys, comprising the following steps: S1. Weigh the raw material powders corresponding to each element according to the atomic percentage of each element in the multiphase alloy, including tantalum powder, niobium powder, and zirconium hydride powder, all with a purity ≥99.5% and a particle size of 30~50 μm; mix the materials according to the proportions to ensure that the final alloy contains elemental Ta phase, Ta... 40 Nb 60 solid solution phase, Nb 20 Zr 80 The molar percentages of the solid solution phase were 30%, 50%, and 20%, respectively.

[0033] S2. Raw material loading: Place the prepared powder raw material, grinding balls and grinding jar into the glove box. Place the required powder into the grinding jar in the glove box. The glove box is preferably filled with an argon atmosphere and the pressure is greater than atmospheric pressure.

[0034] S3. Weigh 0.2 mol of tantalum powder and 0.3 mol of niobium powder into a ball mill jar and ball mill for 30 h to obtain a uniform tantalum-niobium alloy powder (Ta). 40 Nb 60 The tantalum atomic ratio in the alloy powder is 40%; 0.04 mol of niobium powder and 0.16 mol of zirconium hydride powder are weighed and ball-milled in a ball mill jar for 25 h to obtain a uniform niobium-zirconium alloy powder (Nb). 20 Zr 80 The atomic percentage of zirconium in the alloy powder is 80%. 0.3 mol of tantalum powder is weighed and mixed with the above two alloy powders and ball-milled for 2 h to obtain a uniformly mixed composite alloy powder. The ball milling speed is 200 r / min and the ball-to-material ratio is 5:1.

[0035] S4. The ball-milled metal powder is sieved in a vacuum glove box to a mesh size of 100, and the sieved material is collected.

[0036] S5. Place the titanium foil (0.05 mm thick) into the graphite mold, then put the sieved material obtained in S4 into the mold and vibrate it to compact it.

[0037] S6. Place the mold containing alloy powder in a rapid hot pressing sintering furnace, evacuate to below 50 Pa, heat to 900 ℃ at a heating rate of 90 ℃ / min, hold for 5 min to ensure uniform heating of the material; then heat to 1150 ℃ at a heating rate of 100 ℃ / min, hold for 10 min, sinter at a pressure of 80 MPa, and cool with the furnace after holding to obtain TaNbZr multiphase alloy material.

[0038] Samples of the obtained TaNbZr multiphase alloy were taken, the alloy microstructure was observed, and a dynamic compression test (GJB 8799-2015) was conducted. The results are shown in Table 1. The density of the obtained multiphase alloy is close to the theoretical density, proving that the material has good density after sintering. Figure 1 The microstructure of the multiphase alloy material is as follows: Figure 1 As shown in the figure, the Ta phase, TaNb solid solution phase, and NbZr solid solution phase are uniformly distributed.

[0039] Table 1

[0040] Example 2 A Ta 62 Nb 20 Zr 18 A method for preparing multiphase alloys, comprising the following steps: S1. Weigh the raw material powders corresponding to each element according to the atomic percentage of each element in the multiphase alloy, including tantalum powder, niobium powder, and zirconium hydride powder, all with a purity ≥99.5% and a particle size of 30~50 μm; mix the materials according to the proportions to ensure that the final alloy contains elemental Ta phase, Ta... 60 Nb 40 solid solution phase, Nb 40 Zr 60 The molar percentages of the solid solution phases were 50%, 20%, and 30%, respectively.

[0041] S2. Raw material loading: Place the prepared powder raw material, grinding balls and grinding jar into the glove box. Place the required powder into the grinding jar in the glove box. The glove box is preferably filled with an argon atmosphere and the pressure is greater than atmospheric pressure.

[0042] S3. Weigh 0.12 mol of tantalum powder and 0.08 mol of niobium powder into a ball mill jar and ball mill for 25 h to obtain a uniform tantalum-niobium alloy powder (Ta). 60 Nb 40 The tantalum atomic ratio in the alloy powder is 60%; 0.12 mol of niobium powder and 0.18 mol of zirconium hydride powder are weighed and ball-milled in a ball mill jar for 30 h to obtain a uniform niobium-zirconium alloy powder (Nb).40 Zr 60 The atomic percentage of zirconium in the alloy powder is 60%. 0.5 mol of tantalum powder is weighed and mixed with the above two alloy powders and ball-milled for 3 h to obtain a uniformly mixed composite alloy powder. The ball milling speed is 200 r / min and the ball-to-material ratio is 5:1.

[0043] S4. The ball-milled metal powder is sieved in a vacuum glove box to a mesh size of 100, and the sieved material is collected.

[0044] S5. Place the titanium foil (0.05 mm thick) into the graphite mold, then put the sieved material obtained in S4 into the mold and vibrate it to compact it.

[0045] S6. Place the mold containing alloy powder in a rapid hot pressing sintering furnace, evacuate to below 50 Pa, heat to 900 ℃ at a heating rate of 70 ℃ / min, hold for 5 min to ensure uniform heating of the material; then heat to 1200 ℃ at a heating rate of 60 ℃ / min, hold for 20 min, sinter at a pressure of 70 MPa, and cool with the furnace after holding to obtain TaNbZr multiphase alloy material.

[0046] Samples of the obtained TaNbZr multiphase alloy were taken, and the alloy microstructure was observed and a dynamic compression test was conducted (GJB 8799-2015). The results are shown in Table 2. The density of the obtained multiphase alloy is close to the theoretical density, proving that the material has good density after sintering. The microstructure results of the multiphase alloy show that Ta phase, TaNb solid solution phase, and NbZr solid solution phase are uniformly distributed in the alloy.

[0047] Table 2

[0048] Example 3 A Ta 70 Nb 25 The preparation method of Zr5 multiphase alloy includes the following steps: S1. Weigh the raw material powders corresponding to each element according to the atomic percentage of each element in the multiphase alloy, including tantalum powder, niobium powder, and zirconium hydride powder, all with a purity ≥99.5% and a particle size of 30~50 μm; mix the materials according to the proportions to ensure that the final alloy contains elemental Ta phase, Ta... 50 Nb 50 solid solution phase, Nb 50 Zr 50 The molar percentages of the solid solution phases were 50%, 40%, and 10%, respectively.

[0049] S2. Raw material loading: Place the prepared powder raw material, grinding balls and grinding jar into the glove box. Place the required powder into the grinding jar in the glove box. The glove box is preferably filled with an argon atmosphere and the pressure is greater than atmospheric pressure.

[0050] S3. Weigh 0.2 mol of tantalum powder and 0.2 mol of niobium powder into a ball mill jar and ball mill for 25 h to obtain a uniform tantalum-niobium alloy powder (Ta). 50 Nb 50 The tantalum atomic ratio in the alloy powder is 50%; 0.05 mol of niobium powder and 0.05 mol of zirconium hydride powder are weighed and ball-milled in a ball mill jar for 25 h to obtain a uniformly composed niobium-zirconium alloy powder (Nb). 50 Zr 50 The atomic percentage of zirconium in the alloy powder is 50%. 0.5 mol of tantalum powder is weighed and mixed with the above two alloy powders and ball-milled for 2 h to obtain a uniformly mixed composite alloy powder. The ball milling speed is 200 r / min and the ball-to-material ratio is 5:1.

[0051] S4. The ball-milled metal powder is sieved in a vacuum glove box to a mesh size of 100, and the sieved material is collected.

[0052] S5. Place the titanium foil (0.05 mm thick) into the graphite mold, then put the sieved material obtained in S4 into the mold and vibrate it to compact it.

[0053] S6. Place the mold containing alloy powder in a rapid hot pressing sintering furnace, evacuate to below 50 Pa, heat to 900 ℃ at a heating rate of 80 ℃ / min, hold for 5 min to ensure uniform heating of the material; then heat to 1300 ℃ at a heating rate of 100 ℃ / min, hold for 10 min, sinter at a pressure of 100 MPa, and cool with the furnace after holding to obtain TaNbZr multiphase alloy material.

[0054] Samples of the obtained TaNbZr multiphase alloy were taken, and the alloy microstructure was observed and a dynamic compression test was conducted (GJB 8799-2015). The results are shown in Table 3. The density of the obtained multiphase alloy is close to the theoretical density, proving that the material has good density after sintering. The microstructure results of the multiphase alloy show that Ta phase, TaNb solid solution phase, and NbZr solid solution phase are uniformly distributed in the alloy.

[0055] Table 3

[0056] Comparative Example 1: A Ta 50 Nb 34 Zr 16The alloy preparation method differs from that in Example 1 in that it uses long-term ball milling to alloy the powder. The method steps include: S1. Weigh the raw material powders corresponding to each element according to the above composition, including tantalum powder, niobium powder, and zirconium hydride powder, with a purity of ≥99.5% and a particle size of 30~50 μm; S2. Raw material loading: Place the prepared powder raw material, grinding balls and grinding jar into the glove box, and put the required powder into the grinding jar in the glove box. The glove box is preferably filled with an argon atmosphere and the pressure is greater than atmospheric pressure. S3. Tantalum powder, niobium powder, and zirconium hydride powder were ball-milled together for 40 h to obtain a uniform alloy powder. The ball milling speed was 200 r / min and the ball-to-powder ratio was 5:1. The ball milling finally yielded a uniformly mixed alloy powder. S4. The ball-milled metal powder is sieved in a vacuum glove box to a mesh size of 100, and the sieved material is collected.

[0057] S5. Place the titanium foil (0.05 mm thick) into the graphite mold, then put the sieved material obtained in S4 into the mold and vibrate it to compact it.

[0058] S6. Place the mold containing the alloy powder in a rapid hot pressing sintering furnace, evacuate to below 50 Pa, and heat to 900 ℃ at a heating rate of 90 ℃ / min, holding for 5 min to ensure uniform heating of the material. Then heat to the sintering temperature of 1150 ℃ at a heating rate of 100 ℃ / min, holding for 10 min, with a sintering pressure of 80 MPa. After holding, cool with the furnace to obtain the TaNbZr alloy material.

[0059] The obtained TaNbZr alloy material was sampled, the alloy microstructure was observed and a dynamic compression test was conducted (GJB8799-2015). The results are shown in Table 4.

[0060] Table 4

[0061] Compared with Example 1, the blending method generates a single-phase TaNbZr structure instead of a double BCC structure of TaNb and NbZr, resulting in a significant decrease in the strength and plasticity of the material.

[0062] Comparative Example 2 A Ta 65 Nb 19 Zr 16 The preparation method of the multiphase alloy differs from that in Example 1 in that the Ta content in the TaNb phase is too high. The method steps include: S1. Weigh the raw material powders corresponding to each element according to the atomic percentage of each element in the multiphase alloy, including tantalum powder, niobium powder, and zirconium hydride powder, all with a purity ≥99.5% and a particle size of 30~50 μm; mix the materials according to the proportions to ensure that the final alloy contains elemental Ta phase, Ta... 70 Nb 30 solid solution phase, Nb 20 Zr 80 The molar percentages of the solid solution phase were 30%, 50%, and 20%, respectively.

[0063] S2. Raw material loading: Place the prepared powder raw material, grinding balls and grinding jar into the glove box. Place the required powder into the grinding jar in the glove box. The glove box is preferably filled with an argon atmosphere and the pressure is greater than atmospheric pressure.

[0064] S3. Weigh 0.35 mol of tantalum powder and 0.15 mol of niobium powder into a ball mill jar and ball mill for 30 h to obtain a uniform tantalum-niobium alloy powder (Ta). 70 Nb 30 The tantalum atomic ratio in the alloy powder is 70%; 0.04 mol of niobium powder and 0.16 mol of zirconium hydride powder are weighed and ball-milled in a ball mill jar for 25 h to obtain a uniform niobium-zirconium alloy powder (Nb). 20 Zr 80 The atomic percentage of zirconium in the alloy powder is 80%. 0.3 mol of tantalum powder is weighed and mixed with the above two alloy powders and ball-milled for 2 h to obtain a uniformly mixed composite alloy powder. The ball milling speed is 200 r / min and the ball-to-material ratio is 5:1.

[0065] S4. The ball-milled metal powder is sieved in a vacuum glove box to a mesh size of 100, and the sieved material is collected.

[0066] S5. Place the titanium foil (0.05 mm thick) into the graphite mold, then put the sieved material obtained in S4 into the mold and vibrate it to compact it.

[0067] S6. Place the mold containing alloy powder in a rapid hot pressing sintering furnace, evacuate to below 50 Pa, heat to 900 ℃ at a heating rate of 90 ℃ / min, hold for 5 min to ensure uniform heating of the material; then heat to 1150 ℃ at a heating rate of 100 ℃ / min, hold for 10 min, sinter at a pressure of 80 MPa, and cool with the furnace after holding to obtain TaNbZr multiphase alloy material.

[0068] The obtained TaNbZr multiphase alloy material was sampled, the alloy microstructure was observed and a dynamic compression test was conducted (GJB 8799-2015). The results are shown in Table 5.

[0069] Table 5

[0070] Compared with Example 1, a three-phase structure of Ta phase, TaNb phase and NbZr phase was generated in the microstructure. However, the atomic ratio of Ta in the TaNb phase was 70%, which exceeded the required range, resulting in a significant decrease in the strength and plasticity of the material.

[0071] Comparative Example 3 A Ta 50 Nb 34 Zr 16 The preparation method of the multiphase alloy differs from that in Example 1 in that the holding time during sintering is longer. The method steps include: S1. Weigh the raw material powders corresponding to each element according to the atomic percentage of each element in the multiphase alloy, including tantalum powder, niobium powder, and zirconium hydride powder, all with a purity ≥99.5% and a particle size of 30~50 μm; mix the materials according to the proportions to ensure that the final alloy contains elemental Ta phase, Ta... 40 Nb 60 solid solution phase, Nb 20 Zr 80 The molar percentages of the solid solution phase were 30%, 50%, and 20%, respectively.

[0072] S2. Raw material loading: Place the prepared powder raw material, grinding balls and grinding jar into the glove box. Place the required powder into the grinding jar in the glove box. The glove box is preferably filled with an argon atmosphere and the pressure is greater than atmospheric pressure.

[0073] S3. Weigh 0.2 mol of tantalum powder and 0.3 mol of niobium powder into a ball mill jar and ball mill for 30 h to obtain a uniform tantalum-niobium alloy powder (Ta). 40 Nb 60 The tantalum atomic ratio in the alloy powder is 40%; 0.04 mol of niobium powder and 0.16 mol of zirconium hydride powder are weighed and ball-milled in a ball mill jar for 25 h to obtain a uniform niobium-zirconium alloy powder (Nb). 20 Zr 80 The atomic percentage of zirconium in the alloy powder is 80%. 0.3 mol of tantalum powder is weighed and mixed with the above two alloy powders and ball-milled for 2 h to obtain a uniformly mixed composite alloy powder. The ball milling speed is 200 r / min and the ball-to-material ratio is 5:1.

[0074] S4. The ball-milled metal powder is sieved in a vacuum glove box to a mesh size of 100, and the sieved material is collected.

[0075] S5. Place the titanium foil (0.05 mm thick) into the graphite mold, then put the sieved material obtained in S4 into the mold and vibrate it to compact it.

[0076] S6. Place the mold containing alloy powder in a rapid hot pressing sintering furnace, evacuate to below 50 Pa, heat to 900 ℃ at a heating rate of 90 ℃ / min, hold for 10 min to ensure uniform heating of the material; then heat to 1200 ℃ at a heating rate of 60 ℃ / min, hold for 30 min, sinter at a pressure of 70 MPa, and cool with the furnace after holding to obtain TaNbZr multiphase alloy material.

[0077] The obtained TaNbZr multiphase alloy material was sampled, the alloy microstructure was observed and dynamic compression test was carried out (GJB 8799-2015), and the results are shown in Table 6.

[0078] Table 6

[0079] Compared with Example 1, due to the excessively long heat preservation time, the TaNbZr phase was generated in the material, and less elemental Ta phase was retained in the material, which ultimately led to a significant decrease in the strength and plasticity of the material.

[0080] Comparative Example 4 A Ta 80 Nb 15 The preparation method of Zr5 multiphase alloy includes the following steps: S1. Weigh the raw material powders corresponding to each element according to the atomic percentage of each element in the multiphase alloy, including tantalum powder, niobium powder, and zirconium hydride powder, all with a purity ≥99.5% and a particle size of 30~50 μm; mix the materials according to the proportions to ensure that the final alloy contains elemental Ta phase, Ta... 50 Nb 50 solid solution phase, Nb 50 Zr 50 The molar percentages of the solid solution phases were 70%, 20%, and 10%, respectively.

[0081] S2. Raw material loading: Place the prepared powder raw material, grinding balls and grinding jar into the glove box. Place the required powder into the grinding jar in the glove box. The glove box is preferably filled with an argon atmosphere and the pressure is greater than atmospheric pressure.

[0082] S3. Weigh 0.1 mol of tantalum powder and 0.1 mol of niobium powder and ball mill them in a ball mill jar for 25 h to obtain a uniform tantalum-niobium alloy powder with tantalum atomic percentage of 50%. Weigh 0.05 mol of niobium powder and 0.05 mol of zirconium hydride powder and ball mill them in a ball mill jar for 25 h to obtain a uniform niobium-zirconium alloy powder with zirconium atomic percentage of 50%. Weigh 0.7 mol of tantalum powder and ball mill it together with the above two alloy powders for 2 h to obtain a uniformly mixed composite alloy powder. The ball milling speed is 200 r / min and the ball-to-powder ratio is 5:1.

[0083] S4. The ball-milled metal powder is sieved in a vacuum glove box to a mesh size of 100, and the sieved material is collected.

[0084] S5. Place the titanium foil (0.05 mm thick) into the graphite mold, then put the sieved material obtained in S4 into the mold and vibrate it to compact it.

[0085] S6. Place the mold containing alloy powder in a rapid hot pressing sintering furnace, evacuate to below 50 Pa, heat to 900 ℃ at a heating rate of 90 ℃ / min, hold for 5 min to ensure uniform heating of the material; then heat to 1150 ℃ at a heating rate of 100 ℃ / min, hold for 10 min, sinter at a pressure of 80 MPa, and cool with the furnace after holding to obtain TaNbZr multiphase alloy material.

[0086] The obtained TaNbZr multiphase alloy material was sampled, the alloy microstructure was observed and a dynamic compression test was conducted (GJB 8799-2015). The results are shown in Table 7.

[0087] Table 7

[0088] In this comparative example, the content of elemental Ta phase exceeds the selected range, the synergistic effect of the other two phases with Ta phase is weakened, and ultimately the excessive Ta content in the material causes modulus mismatch, resulting in a significant decrease in the strength and plasticity of the material.

[0089] In summary, the invention includes, but is not limited to, the above embodiments. Any equivalent substitutions or partial improvements made under the spirit and principles of this invention shall be considered to be within the protection scope of this invention.

Claims

1. A high-density, high-strength plastic TaNbZr multiphase alloy, characterized by: The multiphase alloy is composed of uniformly distributed Ta phase, TaNb solid solution phase, and NbZr solid solution phase; wherein, based on the total molar amount of Ta phase, TaNb solid solution phase, and NbZr solid solution phase as 100%, the molar percentage of Ta phase is 30%~50%, the molar percentage of TaNb solid solution phase is 20%~50%, and the molar percentage of NbZr solid solution phase is 10%~30%. The atomic ratio of Ta in the TaNb solid solution phase is 35%~65%; the atomic ratio of Zr in the NbZr solid solution phase is 40%~90%. The density of the multiphase alloy is greater than 11 g / cm 3 , dynamic compressive strength ≥ 1700 MPa, and fracture strain ≥ 40%.

2. A high density, high strength, plastic TaNbZr multiphase alloy as claimed in claim 1, characterized by: The TaNb solid solution phase has a BCC structure, and the atomic ratio of Ta is 40%~60%.

3. A high density, high strength, plastic TaNbZr multiphase alloy as in claim 1, wherein: The NbZr solid solution phase has a BCC structure, and the atomic ratio of Zr is 50%~80%.

4. A method for preparing a high-density, high-strength, and ductile TaNbZr multiphase alloy according to any one of claims 1 to 3, characterized in that: The method steps include: (1) Weigh out tantalum powder, niobium powder and zirconium hydride powder according to the proportion of each element in the multiphase alloy; (2) Weigh out a portion of tantalum powder and niobium powder according to the proportion and composition of the TaNb solid solution phase in the multiphase alloy, mix them and ball mill them to obtain TaNb alloy powder with uniform composition. The remaining niobium powder and zirconium hydride powder were mixed and ball-milled to obtain NbZr alloy powder with uniform composition. The remaining tantalum powder was mixed with TaNb alloy powder and NbZr alloy powder and then ball-milled to obtain a uniformly mixed composite alloy powder. (3) The composite alloy powder is loaded into a graphite mold, placed in a sintering furnace, and vacuumed. First, the temperature is raised to 850~950 ℃ at a heating rate of 70 ℃ / min or higher, and sintered at that temperature for 3~5 min. Then, the temperature is raised to 1150~1300 ℃ at a heating rate of 50 ℃ / min or higher, and pressure is applied to 60~110 MPa. Sintering is carried out at that temperature and pressure for 10~20 min. After the holding period, a high-density, high-strength, and ductile TaNbZr multiphase alloy is obtained.

5. The method for preparing a high-density, high-strength, and ductile TaNbZr multiphase alloy as described in claim 4, characterized in that: In step (1), the tantalum powder, niobium powder and zirconium hydride powder have a purity of ≥95% and a particle size of 30~50μm.

6. The method for preparing a high-density, high-strength, and ductile TaNbZr multiphase alloy as described in claim 4, characterized in that: In step (2), the ball milling speed is 200~400 r / min, the ball-to-material ratio is 5:1~10:1, the ball milling time for preparing TaNb alloy powder and NbZr alloy powder is 20~30 h, and the ball milling time for preparing composite alloy powder is 2~5 h.

7. The method for preparing a high-density, high-strength, and ductile TaNbZr multiphase alloy as described in claim 4, characterized in that: In step (3), a metal foil with a temperature 200°C or lower than the sintering temperature is placed inside the graphite mold, and the thickness of the metal foil is less than or equal to 0.05 mm.

8. The method for preparing a high-density, high-strength, and ductile TaNbZr multiphase alloy as described in claim 4, characterized in that: In step (3), the temperature is increased to 850-950 ℃ at a heating rate of 70-90 ℃ / min.

9. The method for preparing a high-density, high-strength, and ductile TaNbZr multiphase alloy as described in claim 4, characterized in that: In step (3), the temperature is increased to 1150-1300 ℃ at a heating rate of 50-100 ℃ / min.

10. The method for preparing a high-density, high-strength, and ductile TaNbZr multiphase alloy as described in claim 4, characterized in that: In step (3), the pressure is increased to 70~100 MPa.

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