Tantalum-tungsten-based alloy with high plasticity and toughness and preparation method of tantalum-tungsten-based alloy

Abstract

The invention relates to a high-ductility and high-toughness tantalum-tungsten-based alloy and a preparation method thereof, and belongs to the technical field of metal materials. The alloy is composed of a BCC phase, a plastic carbide reinforced phase M2C-HCP phase and an HfO2 phase, and the preparation method of the alloy mainly comprises the two steps that (1) alloy powder is prepared through a multi-step feeding low-energy ball milling method, and powder which is low in oxygen content, small in particle size and dispersively distributed in Hf element is obtained; and 2) a block sample is obtained by adopting an SPS sintering method, and the block sample is outstanding in room-temperature plasticity and good in high-temperature strength. The oxygen content of the sample is low, oxides are distributed in a dispersed manner, and the size of the sample is nano-scale; the size of the carbide is in a micron order, the structure of the carbide is M2C-HCP, and the carbide has plastic deformation capacity. The preparation method disclosed by the invention has the characteristics of safety, high efficiency, convenience and cleanness in operation and short preparation period; the prepared alloy has outstanding room-temperature plasticity and good high-temperature strength, the room-temperature fracture strain of the alloy is about 19% and is 9 times that of an NbMoTaW high-entropy alloy, and the ultimate compressive strength at the temperature of 1750 DEG C is 425.7 MPa and is close to the strength of the NbNbMoTaW alloy at the temperature of 1600 DEG C.

Description

Technical Field

[0001] The invention relates to a high-plasticity tantalum-tungsten based alloy and a preparation method thereof, belonging to the technical field of metal materials. Background Art

[0002] With the acceleration of equipment renewal and localization in the aviation and aerospace fields, the potential market demand for high-temperature refractory high-entropy alloys has intensified. The commonly used Ni-based high-temperature alloys have a low melting point, and their yield strength drops sharply with increasing temperature at high temperatures above 1100°C. Refractory high-temperature alloys still have excellent mechanical properties in a temperature environment above 1100°C, and are expected to make up for the vacancy of Ni-based high-temperature alloys in the ultra-high temperature field. Therefore, high-temperature refractory high-entropy alloys have become potential alternative materials for aircraft engines.

[0003] The biggest feature of refractory high-temperature alloys is their excellent high-temperature yield strength and high-temperature stability, but their severe room-temperature brittleness limits the industrial application of the material.

[0004] In recent years, with the in-depth research of many scholars on refractory high entropy alloys, many refractory alloys with different composition systems have been prepared by arc melting, and the mechanical properties of these alloys have been greatly improved. However, the refractory high-temperature alloys prepared by arc melting have problems such as large grain size and uneven alloy composition, as well as high processing costs and difficulties in forming complex structural parts.

[0005] The alloy prepared by high-energy ball milling-spark plasma sintering has the advantages of uniform composition, small grains, and low sintering temperature, which greatly overcomes the problems of arc melting in preparing refractory alloys. However, during the ball milling process, the metal powder will undergo an unavoidable oxidation reaction. In addition, high-energy ball milling generally has serious sticking problems. After sticking, the particle size and type of the material are very uneven. After sintering, the grain size uniformity and phase uniformity of the alloy, especially the distribution uniformity of the oxide, are very poor, and the oxide size is large. During the sintering process, the oxygen in the powder will combine with a certain oxygen-loving element and be distributed in large quantities at the grain boundaries of the alloy structure, so that the toughness of the alloy drops significantly. Therefore, it is necessary to avoid excessive oxygen content in the powder after ball milling, and to inhibit the large-scale combination of oxygen elements and oxygen-loving elements in the powder during the sintering process to form large-sized oxide grains, which seriously damages the high plastic toughness of the alloy. Summary of the invention

[0006] In order to solve some problems existing in the methods of preparing alloys by arc melting and liquid forming, avoid the process of deoxidizing the powder due to excessive oxygen content of the alloy powder after ball milling, and overcome the sticking phenomenon that is prone to occur in high-energy ball milling, the present invention provides a high-plasticity and toughness tantalum-tungsten-based alloy and a preparation method thereof. The present invention adopts a method for preparing Mo-Nb-Re-Hf-Ta-WC alloy material by a "multi-step feeding low-energy ball milling-spark plasma sintering" process. The method is simple and safe to operate, low in cost, and short in preparation cycle. The obtained Ta-W-based alloy material has good room temperature plasticity.

[0007] The present invention is achieved through the following technical solutions.

[0008] A high plasticity and toughness tantalum-tungsten based alloy, the high plasticity and toughness tantalum-tungsten based alloy is composed of a BCC phase, a plastic carbide reinforcement phase M2C-HCP phase and a HfO2 phase. The high plasticity and toughness tantalum-tungsten based alloy is a non-equiatomic ratio composition Mo-Nb-Re-Hf-Ta-WC, denoted as Mo a Nb b Re c Hf d Ta e W f C g , where the corresponding molar ratios of each element are a, b, c, d, e, f and g; a is 0-0.6, b is 0-1.8, c is 0.01-0.2, d is 0.02-0.8, e is 0.6-3.5, f is 0.1-0.7, and g is 0-1.

[0009] Said a=0.15, b=0.9, c=0.14, d=0.75, e=3.15, f=0.65, g=1.

[0010] Said a=0.06, b=0.1, c=0.2, d=0.6, e=2.95, f=0.5, g=0.7.

[0011] A method for preparing a high-plasticity and toughness tantalum-tungsten based alloy is prepared by the following steps:

[0012] Step 1: The first step is ball milling: firstly, the larger particle size brittle materials are ball milled separately, the purpose is to crush the materials, reduce the particle size, and obtain multiple small particle size brittle materials. The brittle materials are W, Mo, HfH2 and TaC;

[0013] Step 2: Second ball milling: After the plurality of small-particle brittle materials are mixed after the first ball milling, they are mixed with part of the plastic material and ball milled to obtain a preliminary mixed powder, wherein the part of the plastic material is Nb and Re;

[0014] Step 3: The third ball milling step: ball milling the preliminary mixed powder and the remaining plastic powder, the remaining plastic material is Ta, to obtain the desired mixed powder;

[0015] Step 4: Place the mixed powder in a vacuum drying oven for drying;

[0016] Step 5: The required mixed powder is subjected to spark plasma sintering to obtain a tantalum-tungsten based alloy with high plasticity and toughness.

[0017] The first step ball milling, the second step ball milling and the third step ball milling are all dry grinding, the ball-to-material ratio is 3:1-8:1, the grinding balls are WC grinding balls, and the large, medium and small ratio is 1:1:1; the ball milling speed is 150-200r / min, and the ball milling time is 4-10h; the ball mill operation process: 10min forward rotation, 10min reverse rotation, and cross operation; in every 10min, the ball mill runs at 150-200r / min for 4-6min, and then stops for 4-6min.

[0018] The ball milling process is performed in an argon environment, and the temperature of the ball milling jar is maintained below 5° C. during the ball milling process.

[0019] The spark plasma sintering is as follows: heating is performed under a vacuum environment of 1Pa, with a heating rate of 100±10℃ / min, firstly the temperature is raised to 850±50℃, and the temperature is kept at this temperature for 15 to 30min; after the temperature is kept at this temperature, vacuum is drawn, and then the sintering temperature is raised to 1800±100℃, and the temperature is kept at this temperature for 15 to 30min, the pressure is 35±5MPa, and after the heating, the furnace is cooled at a rate of 25±5℃ / min. The temperature is quickly raised to 850±50℃ and kept at this temperature.

[0020] The spark plasma sintering is carried out in a graphite mold, and the diameter of the graphite mold is 20 mm.

[0021] The vacuum drying is performed by heating the temperature to 80° C. to 100° C. under vacuum and then keeping the temperature for 1 to 2 hours.

[0022] The high plasticity and toughness tantalum-tungsten based alloy of the present invention introduces C element through carbide. The diffusion of C element reduces the sintering temperature and improves the density of the alloy. "Ball milling-sintering" forms small-sized plastic carbides, which can coordinate deformation with the base metal and give the alloy good plasticity and toughness.

[0023] The high-plasticity and toughness tantalum-tungsten-based alloy of the present invention introduces Hf element through hydride, and the Hf element is evenly distributed in the alloy matrix through ball milling alloying, which is used to fix oxygen and induce material purification, forming a uniform and fine oxide dispersed phase distributed in the crystal, thereby avoiding plastic degradation caused by oxides, and the dispersed oxides have a strengthening effect, thereby ensuring the high plasticity of the alloy.

[0024] The invention introduces HfH2 raw material ball milling, which is beneficial to obtain metal powder with smaller particle size, makes it evenly distributed in the alloy powder, and reduces the oxidation degree of Hf element in the ball milling process.

[0025] The present invention introduces HfH2 raw material sintering, and utilizes a small amount of H2 released by HfH2 during the sintering process to reduce a portion of oxygen elements in the alloy powder, thereby being able to safely and efficiently reduce the oxygen content of the alloy and improve the performance of the alloy.

[0026] The key to the preparation method involved in the present invention lies in the regulation of oxides and carbides, which is the key to obtaining good room temperature plasticity and high temperature strength. For oxides, it mainly involves their content, size and distribution; for carbides, it mainly involves the regulation of carbide microstructure, size and distribution. Compared with the existing methods for preparing high-temperature alloys, the method for preparing refractory high-temperature alloys in the present invention has the following advantages:

[0027] 1. The alloy preparation method is simple and convenient to operate, safe and efficient, and has a short preparation cycle;

[0028] 2. The ball milling process of this preparation method will not cause the pot sticking phenomenon, the prepared powder particle size is small, the alloy powder composition is uniform, and the alloy composition after sintering is uniform;

[0029] 3. The powder prepared by this preparation method has a low oxygen content, the oxygen content of the alloy after sintering is low, the oxide particle size is small, nanometer size, and is dispersed in the BCC phase matrix, which has little effect on the plasticity and toughness of the alloy.

[0030] 4. The carbide of the tantalum-tungsten-based alloy obtained by this preparation method is a M2C type close-packed hexagonal structure, and its microstructure is similar to Max, with a certain plastic deformation ability and good coordination with the plastic strain of the matrix; in addition, the carbide phase size is relatively small, at the micron scale. This feature gives the material good room temperature plasticity.

[0031] Compared with the currently available high-temperature materials, the high-plasticity and toughness tantalum-tungsten-based alloy in the present invention has the following advantages:

[0032] 1. At room temperature, the alloy has outstanding plasticity. The room temperature fracture strain of the alloy in Example 1 is 9 times that of the NbMoTaW high entropy alloy, and the room temperature fracture strain of the alloy in Example 2 is 12.86 times that of the NbMoTaW high entropy alloy;

[0033] 2. At 1750°C, the alloy exhibits excellent strength, significantly exceeding that of traditional refractory alloys and close to the strength of NbNbMoTaW high entropy alloy at 1600°C. In Example 1, its ultimate compressive strength is 425.7 MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1Mo after two-step ball milling in Example 1 of the present invention 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 C Scanning electron microscope image of high plasticity and toughness tantalum-tungsten based alloy powder;

[0035] Figure 2 Mo after three-step ball milling in Example 1 of the present invention 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 C Scanning electron microscope image of high plasticity and toughness tantalum-tungsten based alloy powder;

[0036] Figure 3 The Mo prepared in Example 1 of the present invention 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 C Room temperature compressive stress-strain curve of high plasticity and toughness tantalum-tungsten based alloy;

[0037] Figure 4 The Mo prepared in Example 1 of the present invention 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 C High temperature mechanical properties test diagram of high plasticity and toughness tantalum-tungsten based alloy;

[0038] Figure 5 The Mo prepared in Example 1 of the present invention 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 C Scanning electron microscope image of high plasticity and toughness tantalum-tungsten based alloy;

[0039] Figure 6 The Mo prepared in Example 2 of the present invention 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 Room temperature compressive stress-strain curve of high plasticity and toughness tantalum-tungsten based alloy;

[0040] Figure 7The Mo prepared in Example 2 of the present invention 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 Test diagram of high temperature mechanical properties of high plasticity and toughness tantalum-tungsten based alloy.

[0041] Figure 8 The Mo prepared in Example 2 of the present invention 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 XRD pattern of high plasticity and toughness tantalum-tungsten based alloy;

[0042] Fig. 9 The Mo prepared in Example 2 of the present invention 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 Scanning electron microscope image of high plasticity and toughness tantalum-tungsten based alloy;

[0043] Fig.10 The Mo prepared in Example 2 of the present invention 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 Scanning electron microscope image of the compression fracture of high plasticity and toughness tantalum-tungsten based alloy. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

[0045] The present invention is further described below in conjunction with specific embodiments.

[0046] Example 1: Mo 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 Preparation of Tantalum-Tungsten Based Alloy with High Plasticity and Toughness

[0047] Mo 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta3.15 W 0.65 The preparation method of C high temperature refractory alloy comprises the following steps:

[0048] Step 1: Separate the larger particle size brittle materials Mo, W, TaC, HfH2 powders and perform separate ball milling. Use a planetary ball mill for dry milling. The ball-to-material ratio is 5:1 (WC grinding balls, large, medium and small ball mass ratio is 1:1:1), the ball mill speed is 200r / min, and the ball milling time is 10h. Ball mill operation process: 10min forward rotation, 10min reverse rotation, and cross operation. In each 10min, the ball mill runs at 200r / min for 5min and then stops for 5min. The ball milling process maintains the ball milling jar temperature below 5℃. Finally, multiple small particle size brittle materials are obtained.

[0049] Step 2: Add Nb, Re powder and all the mixed brittle materials after the first step of ball milling, and use a planetary ball mill for dry grinding, with a ball-to-material ratio of 8:1 (WC grinding balls, large, medium and small ball mass ratio of 1:1:1), a ball mill speed of 150r / min, and a ball milling time of 10h. Ball mill operation process: 10 minutes forward rotation, 10 minutes reverse rotation, and cross operation. In each 10 minutes, the ball mill runs at 150r / min for 5 minutes and then stops for 5 minutes. The ball milling process maintains the temperature of the ball mill below 5°C. The preliminary mixed powder is obtained, and the SEM of the alloy powder after preliminary ball milling is as follows Figure 1 shown.

[0050] Step 3: Take out the preliminary ball-milled powder from the vacuum glove box, add metal Ta powder and an appropriate amount of grinding balls, and continue to use the planetary ball mill for dry grinding. Ball-to-material ratio 8:1 (WC grinding balls, mass ratio of large, medium and small balls 1:1:1), ball mill speed 180r / min, ball milling time 4h. Ball mill operation process: 10min forward rotation, 10min reverse rotation, cross operation. In each 10min, the ball mill runs at 180r / min for 6min and then stops for 4min. The ball milling process maintains the temperature of the ball mill below 5°C. The SEM of the alloy powder after three-step ball milling is as follows: Figure 2 shown.

[0051] Step 4: Take out the final ball-milled powder from the vacuum glove box, and then place it in a vacuum drying oven for drying. Raise the temperature in the vacuum drying oven to 90° C. and keep it warm for 2 h.

[0052] Step 5: Put the mixed powder into a Φ20mm graphite mold, and perform spark plasma sintering in a SINTER LAND type LABOX-650F equipment. Heat up in a vacuum environment at a heating rate of 100±10℃ / min. First, heat to 850±50℃ and keep it at this temperature for 20min; after the insulation is completed, vacuumize, then increase the sintering temperature to 1800±50℃, and keep it at this temperature for 20min, the pressure is 35±5MPa, and cool with the furnace after the heating is completed at a rate of 25±5℃ / min. After cooling, Mo is obtained. 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 C High plasticity and toughness tantalum-tungsten based alloy.

[0053] Mo 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 C Mechanical properties test of high plasticity and toughness tantalum-tungsten based alloy at room temperature:

[0054] 1. Room temperature compression test:

[0055] First, Mo 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 C high plasticity and toughness tantalum-tungsten based alloy is made into a Φ5mm×7.5mm cylindrical test sample. The two end faces of the cylinder are polished flat. The room temperature compression performance of the sample is tested using a UTM5105X microcomputer-controlled electronic universal material testing machine. The strain rate is selected as 0.001s -1 , and then subjected it to room temperature compression test to test the alloy strength and plasticity. Figure 3 As shown, Mo 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 The room temperature compressive strength of C high temperature refractory alloy is 1963.4MPa, and the fracture strain is 17.78%.

[0056] 2. High temperature compression test:

[0057] First, Mo 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W0.65 C high plasticity and toughness tantalum-tungsten based alloy was made into a Φ5mm×7.5m cylindrical test sample. The two end faces of the cylinder were polished flat. The compression performance of the sample was tested at 1750℃ using a Gleeble3500 thermal simulation device. The sample was heated at a rate of 10℃ / s. When the temperature rose to the test temperature, it was kept warm for 1 minute and then compressed. The strain rate was selected as 0.01s -1 .Depend on Figure 4 It can be seen that Mo 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 The yield strength of C high-plasticity and toughness tantalum-tungsten based alloy at 1750°C is above 350MPa, and the ultimate compressive strength reaches 425.7MPa. Its performance at high temperature far exceeds that of traditional high-temperature alloys, and it is expected to become a new type of high-temperature alloy.

[0058] 3. Microstructure analysis:

[0059] The microstructure of the sample was analyzed using a Guoyi Quantum SEM5000 scanning electron microscope, using secondary electron signals, an emission voltage of 15kV, and a magnification of 1000 times. The results are as follows Figure 5 As shown: The obtained Mo 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 C high plasticity and toughness tantalum-tungsten based alloy has a eutectic structure, which is composed of the main phase BCC phase, Ta2C phase carbide, MC phase and a small amount of HfO2 and other phases.

[0060] 4. Density test:

[0061] The Archimedes drainage method was used for measurement. The specific operation steps were as follows: Mo prepared in Example 1 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 C high-temperature high-entropy alloy was prepared into 4 cylindrical specimens of Φ5mm×7.5mm. Before measurement, they were placed in a beaker containing anhydrous ethanol, cleaned with ultrasonic oscillation for 3-5min, taken out and blown dry, and then the dry weight M1 of each specimen was weighed using a FA224L electronic balance (accuracy 0.1mg). Each specimen was weighed 3-5 times to reduce the measurement error; then, the mass M2 of each specimen in water was weighed, and each specimen was weighed 3-5 times; finally, the density was calculated according to the following formula:

[0062]

[0063] Where ρ1 is the density of water, 0.99705 g / cm 3 (25℃); ρ2 is air density, 0.0012g / cm 3 .

[0064] After calculation, the Mo prepared in Example 1 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 C high plastic toughness tantalum tungsten based alloy density is 15.4243g / cm 3 .

[0065] 5. Hardness test:

[0066] The DHV-1000 micro Vickers hardness tester was used for the test. Before the measurement, the upper and lower surfaces of the sample were ground flat and kept parallel, the measuring surface was polished, and the average value was taken after testing 3 to 5 different points. The measured Vickers hardness was 549.98 HV.

[0067] Example 2: Mo 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 Preparation of Tantalum-Tungsten Based Alloy with High Plasticity and Toughness

[0068] Mo 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 The preparation method of high plasticity and toughness tantalum-tungsten based alloy comprises the following steps:

[0069] Step 1: Separate the larger particle size brittle materials Mo, W, TaC, HfH2 powders and perform separate ball milling. Use a planetary ball mill for dry milling. The ball-to-material ratio is 6:1 (WC grinding balls, large, medium and small ball mass ratio is 1:1:1), the ball mill speed is 200r / min, and the ball milling time is 8h. Ball mill operation process: 10min forward rotation, 10min reverse rotation, and cross operation. In each 10min, the ball mill runs at 200r / min for 6min and then stops for 4min. The ball milling process maintains the ball milling jar temperature below 5°C. Finally, multiple small particle size brittle materials are obtained.

[0070] Step 2: Add Nb, Re powder and all the brittle materials mixed after the first step of ball milling, and use a planetary ball mill for dry grinding, with a ball-to-material ratio of 8:1 (WC grinding balls, large, medium and small ball mass ratio of 1:1:1), a ball mill speed of 150r / min, and a ball milling time of 10h. Ball mill operation process: 10min forward rotation, 10min reverse rotation, and cross operation. In each 10min, the ball mill runs at 150r / min for 5min and then stops for 5min. Finally, the preliminary mixed powder is obtained, and the ball milling jar temperature is maintained below 5℃ during the ball milling process.

[0071] Step 3: Take out the preliminary ball milled powder in the vacuum glove box, add metal Ta powder and an appropriate amount of grinding balls, and continue to use the planetary ball mill for dry grinding. The ball-to-material ratio is 8:1 (WC grinding balls, the mass ratio of large, medium and small balls is 1:1:1), the ball mill speed is 180r / min, and the ball milling time is 4h. Ball mill operation process: 10min forward rotation, 10min reverse rotation, and cross operation. In each 10min, the ball mill runs at 180r / min for 6min and then stops for 4min. The ball milling process maintains the ball milling jar temperature below 5℃.

[0072] Step 4: Take the ball-milled powder out of the vacuum glove box, and then place it in a vacuum drying oven for drying. The mixed powder is heated to 100° C. in the vacuum drying oven and kept warm for 1 hour.

[0073] Step 5: Put the mixed powder into a Φ20mm graphite mold, and perform spark plasma sintering in a SINTER LAND type LABOX-650F device. Heat up in a vacuum environment at a heating rate of 100±10℃ / min. First, heat to 850±50℃ and keep at this temperature for 15min; after the insulation, evacuate the vacuum, then raise the sintering temperature to 1800±50℃, and keep at this temperature for 30min, with a pressure of 35±5MPa. After the heating is completed, cool with the furnace at a rate of 25±5℃ / min. After cooling, Mo is obtained. 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 High temperature refractory alloy.

[0074] Mo 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 Mechanical properties test of high plasticity and toughness tantalum-tungsten based alloy at room temperature and high temperature:

[0075] 1. Room temperature compression test:

[0076] First, Mo 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 A cylindrical test sample of Φ5mm×7.5mm was made of high-temperature refractory alloy. Both ends of the cylinder were polished flat. The room temperature compression performance of the sample was tested using a UTM5105X microcomputer-controlled electronic universal material testing machine. The strain rate was selected as 0.001s -1 , and then subjected it to room temperature compression test to test the alloy strength and plasticity. Figure 6 As shown, Mo 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 The room temperature compressive strength of the high temperature refractory alloy is 2250MPa and the fracture strain is 22.58%.

[0077] 2. High temperature compression test:

[0078] First, Mo 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 A cylindrical test sample of Φ5mm×7.5m was made of high-temperature refractory alloy. Both ends of the cylinder were polished flat. The compression performance of the sample was tested at 1750℃ using a Gleeble3500 thermal simulation device. The sample was heated at a rate of 10℃ / s. When the temperature reached the test temperature, it was kept warm for 1min before compression began. The strain rate was selected as 0.01s -1 .Depend on Figure 7 It can be seen that Mo 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 The high-temperature refractory alloy has a yield strength of 276MPa at 1750°C and an ultimate compressive strength of 317MPa. Its performance at high temperatures far exceeds that of traditional high-temperature alloys and is expected to become a new type of high-temperature alloy.

[0079] 3. Phase analysis and microscopic analysis:

[0080] Mo 0.06 Nb0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 XRD spectrum of high plasticity and toughness tantalum-tungsten based alloy, such as Figure 8 shown.

[0081] Mo 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 Scanning electron microscope image of high plasticity and toughness tantalum-tungsten based alloy, such as Fig. 9 shown.

[0082] Mo 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 The scanning electron microscope image of the compression fracture of the high-ductility tantalum-tungsten alloy shows obvious torsional deformation of small-sized plastic carbides, such as Fig.10 shown.

[0083] 4. Density and hardness test:

[0084] The prepared Mo 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 The high plasticity and toughness tantalum-tungsten based alloy was tested for density and hardness. 0.06 Nb 0.1 Re 0.2 Hf 0.6 Ta 2.95 W 0.5 C 0.7 The density of high plasticity and toughness tantalum-tungsten based alloy is 15.7068g / cm 3 , hardness is 491.1HV.

[0085] Example 3

[0086] Mo 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 Preparation of Tantalum-Tungsten Based Alloy with High Plasticity and Toughness

[0087] Mo 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 The preparation method of C high temperature refractory alloy comprises the following steps:

[0088] Step 1: Separate the larger particle size brittle materials Mo, W, TaC, HfH2 powders and perform separate ball milling. Use a planetary ball mill for dry milling. The ball-to-material ratio is 3:1 (WC grinding balls, large, medium and small ball mass ratio is 1:1:1), the ball mill speed is 180r / min, and the ball milling time is 10h. Ball mill operation process: 10min forward rotation, 10min reverse rotation, and cross operation. In each 10min, the ball mill runs at 180r / min for 6min and then stops for 4min. The ball milling process maintains the ball milling jar temperature below 5°C. Finally, multiple small particle size brittle materials are obtained.

[0089] Step 2: Add Nb, Re powder and all the mixed brittle materials after the first step of ball milling, and use a planetary ball mill for dry grinding, with a ball-to-material ratio of 8:1 (WC grinding balls, large, medium and small ball mass ratio of 1:1:1), a ball mill speed of 150r / min, and a ball milling time of 10h. Ball mill operation process: 10min forward rotation, 10min reverse rotation, and cross operation. In each 10min, the ball mill runs at 180r / min for 5min and then stops for 5min. The ball milling process maintains the temperature of the ball mill below 5℃. Get the preliminary mixed powder.

[0090] Step 3: Take out the preliminary ball milled powder in the vacuum glove box, add metal Ta powder and an appropriate amount of grinding balls, and continue to use the planetary ball mill for dry grinding. The ball-to-material ratio is 8:1 (WC grinding balls, the mass ratio of large, medium and small balls is 1:1:1), the ball mill speed is 180r / min, and the ball milling time is 4h. Ball mill operation process: 10min forward rotation, 10min reverse rotation, and cross operation. In each 10min, the ball mill runs at 180r / min for 6min and then stops for 4min. The ball milling process maintains the ball milling jar temperature below 5℃.

[0091] Step 4: Take out the final ball-milled powder from the vacuum glove box, and then place it in a vacuum drying oven for drying. Raise the temperature in the vacuum drying oven to 90° C. and keep it warm for 2 h.

[0092] Step 5: Put the mixed powder into a Φ20mm graphite mold, and perform spark plasma sintering in a SINTER LAND type LABOX-650F equipment. Heat up in a vacuum environment at a heating rate of 100±10℃ / min. First, heat to 850±50℃ and keep at this temperature for 30min; after the insulation is completed, vacuumize, then increase the sintering temperature to 1800±50℃, and keep at this temperature for 30min, the pressure is 35±5MPa, and cool with the furnace after the heating is completed at a rate of 25±5℃ / min. After cooling, Mo is obtained. 0.15 Nb 0.9 Re 0.14 Hf 0.75 Ta 3.15 W 0.65 C High plasticity and toughness tantalum-tungsten based alloy.

[0093] The raw materials listed in the present invention, as well as the upper and lower limits and interval values ​​of the raw materials of the present invention, and the upper and lower limits and interval values ​​of the process parameters can realize the present invention, and the embodiments are not listed one by one here. The above is only the preferred implementation mode of the present invention, and of course it cannot be used to limit the scope of the rights of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and changes can be made without departing from the principle of the present invention, and these improvements and changes are also regarded as the protection scope of the present invention.

Claims

1. A high plasticity and toughness tantalum-tungsten based alloy, characterized in that: The high plasticity and toughness tantalum-tungsten based alloy is composed of BCC phase, plastic carbide reinforcement phase M2C-HCP phase and HfO2 phase. The high plasticity and toughness tantalum-tungsten based alloy is a non-equiatomic ratio composition Mo-Nb-Re-Hf-Ta-WC, denoted as Mo a Nb b Re c Hf d Ta e W f C g , where the corresponding molar ratios of each element are a, b, c, d, e, f and g; a is 0-0.6, b is 0-1.8, c is 0.01-0.2, d is 0.02-0.8, e is 0.6-3.5, f is 0.1-0.7, and g is 0-1.

2. The high plasticity and toughness tantalum-tungsten based alloy according to claim 1, characterized in that: Said a=0.15, b=0.9, c=0.14, d=0.75, e=3.15, f=0.65, and g=1.

3. The high plasticity and toughness tantalum-tungsten based alloy according to claim 1, characterized in that: Said a=0.06, b=0.1, c=0.2, d=0.6, e=2.95, f=0.5, g=0.

7.

4. A method for preparing a high plasticity and toughness tantalum-tungsten based alloy according to any one of claims 1 to 3, characterized in that Prepared by the following steps: Step 1: First, ball milling: first, mix the larger particle size brittle materials and then ball mill them to obtain nano-sized powders. The brittle materials are W, Mo, HfH2 and TaC; Step 2: Second ball milling: The nano-sized powder after the first ball milling is mixed with part of the plastic material and ball milled to obtain a preliminary mixed powder, wherein part of the plastic material is Nb and Re; Step 3: The third ball milling step: ball milling the preliminary mixed powder and the remaining plastic powder, the remaining plastic material is Ta, to obtain the desired mixed powder; Step 4: Place the mixed powder in a vacuum drying oven for drying; Step 5: The required mixed powder is subjected to spark plasma sintering to obtain a tantalum-tungsten based alloy with high plasticity and toughness.

5. The method for preparing a high plasticity and toughness tantalum-tungsten based alloy according to claim 4, characterized in that: The first step ball milling, the second step ball milling and the third step ball milling are all dry grinding, the ball-to-material ratio is 3:1-8:1, the grinding balls are WC grinding balls, and the large, medium and small ratio is 1:1:1; the ball milling speed is 150-200r / min, and the ball milling time is 4-10h; the ball mill operation process: 10min forward rotation, 10min reverse rotation, and cross operation; in every 10min, the ball mill runs at 150-200r / min for 4-6min, and then stops for 4-6min.

6. The method for preparing a high plasticity and toughness tantalum-tungsten based alloy according to claim 4, characterized in that: The ball milling process is performed in an argon environment, and the temperature of the ball milling jar is maintained below 5° C. during the ball milling process.

7. The method for preparing a high plasticity and toughness tantalum-tungsten based alloy according to claim 4, characterized in that: The spark plasma sintering is as follows: heating is performed under a vacuum environment of 1Pa, with a heating rate of 100±10℃ / min, firstly the temperature is raised to 850±50℃, and the temperature is kept at this temperature for 15 to 30min; after the temperature is kept at this temperature, vacuum is drawn, and then the sintering temperature is raised to 1800±100℃, and the temperature is kept at this temperature for 15 to 30min, the pressure is 35±5MPa, and after the heating, the furnace is cooled at a rate of 25±5℃ / min. The temperature is quickly raised to 850±50℃ and kept at this temperature.

8. The method for preparing a high plasticity and toughness tantalum-tungsten based alloy according to claim 7, characterized in that: The spark plasma sintering is carried out in a graphite mold, and the diameter of the graphite mold is 20 mm.

9. The method for preparing a high plasticity and toughness tantalum-tungsten based alloy according to claim 4, characterized in that: The vacuum drying is performed by heating the temperature to 80° C. to 100° C. under vacuum and then keeping the temperature for 1 to 2 hours.

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