A method for preparing CuCrNb alloy by rapid hot pressing sintering

Abstract

The invention discloses a method for preparing a CuCrNb alloy by adopting rapid hot pressing and sintering, comprising the following steps: S1, pressing and forming; S2, rapid hot pressing and sintering; S3, solid solution aging treatment. The method adopts Cr2Nb powder+Cu powder as raw materials, and adopts rapid hot pressing and sintering to prepare a novel CuCrNb alloy, with low sintering temperature, fast heating speed and short sintering time, and realizes ultra-rapid densification of CuCrNb by utilizing surface activation and rapid sintering, effectively inhibits the growth of Cr2Nb phase, maintains the original microstructure and size of atomized powder, and the prepared CuCrNb has the characteristics of fine and uniform structure, large quantity and stability, and substantially improves the performance of CuCrNb.

Description

Technical Field

[0001] The invention relates to the technical field of high temperature alloys, and in particular to a method for preparing a CuCrNb alloy by adopting rapid hot pressing and sintering. Background Art

[0002] Laves phase Cr2Nb is a topological close-packed structure with a high degree of space filling. There is no interstitial position that can accommodate Cu atoms. Moreover, Laves phase Cr2Nb is usually a linear compound with LS2 composition, which lays the foundation for the existence of Cr2Nb and Cu in the form of "pseudo-alloy". In addition, Laves phase Cr2Nb not only has high hardness and high melting point, but also has very good high-temperature oxidation resistance and high-temperature strength, very high creep resistance and excellent hot corrosion resistance.

[0003] At present, the conventional method of preparing CuCrNb alloy is smelting. However, the melting point difference between the matrix Cu and the alloying components Cr and Nb of CuCrNb alloy is large, the smelting temperature is high, and the alloy smelting and alloying are difficult. At the same time, during the casting solidification process, Cr and Nb preferentially form a coarse second phase of Cr2Nb, a high melting point and high hardness intermetallic compound, which leads to uneven composition and structure, making it difficult to effectively control through subsequent deformation processing and heat treatment, thereby reducing the performance of the alloy.

[0004] Patent CN114107713A discloses a method for preparing a high temperature resistant CuCrNb alloy by plasma rotary atomization, that is, the atomized CuCrNb alloy powder is weighed according to the designed weight, loaded into a graphite mold after weighing, sintered by a spark plasma sintering process, and the sintered sample is hot-rolled to obtain a CuCrNb alloy hot-rolled sample, and then the CuCrNb alloy hot-rolled sample is aged to obtain a CuCrNb alloy. However, the amount of Cr2Nb strengthening phase in the CuCrNb alloy prepared by this method is small, resulting in large changes in the performance of the material after different degrees of treatment. In addition, the spark plasma sintering equipment is expensive and energy-intensive.

[0005] Therefore, the present invention designs a method for preparing CuCrNb alloy by rapid hot pressing sintering to solve the above problems. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a method for preparing CuCrNb alloy by rapid hot pressing sintering.

[0007] The technical solution of the present invention is: a method for preparing CuCrNb alloy by rapid hot pressing sintering, comprising the following steps:

[0008] S1. Pressing and forming:

[0009] Cr2Nb powder and electrolytic Cu powder are mixed in a mass ratio of 1:1 to obtain a mixed powder; wherein the Cr2Nb powder comprises, by mass percentage, 52.0-56.0% of Cr and 44.0-48.0% of Nb;

[0010] Then, the mixed powder is pressed into a blank with a density of 70 to 80% by a press;

[0011] S2, rapid hot pressing sintering:

[0012] The blank obtained in step S1 is placed in a rapid hot pressing sintering furnace for sintering. First, the pressure is 0.5-1T, and the temperature is increased from room temperature to 600-850°C within 10-15 minutes, and the temperature is kept for 5-15 minutes; then the pressure is adjusted to 10-15T, and the temperature is increased to 900-950°C within 5-10 minutes, and the temperature is kept for 5-10 minutes to obtain a sintered alloy;

[0013] S3, solution aging treatment:

[0014] The sintered alloy obtained in step S3 is subjected to a solution aging treatment in a tubular furnace under an Ar gas protective atmosphere to obtain a CuCrNb alloy.

[0015] Furthermore, in step S1, the method for preparing the Cr2Nb powder comprises the following steps:

[0016] The Cr block and the Nb block are placed in a CaO crucible according to the mass ratio for vacuum induction melting: nitrogen is filled into the melting furnace, and melting begins when the pressure in the furnace reaches 0.01-0.02 MPa, the heating rate is 5-15 kW / min, and the melting power is 270-330 kW, so as to prepare a Cr2Nb alloy;

[0017] The Cr2Nb alloy is subjected to vacuum gas atomization treatment in an argon environment, the gas pressure is 1.5-4.0 MPa, the feed rate is 30-70 mm / min, and solidified at a cooling rate of 100-120 k / s to form Cr2Nb powder.

[0018] Note: The powder particles obtained by vacuum induction melting and vacuum gas atomization can be smaller in size and have a higher degree of grain refinement.

[0019] Furthermore, in step S1, the mixing method of the mixed powder is: ball milling the Cr2Nb powder and the electrolytic Cu powder in a high-speed ball mill at a rotation speed of 280 to 320 r / min for 3.5 to 4.5 hours to obtain the mixed powder.

[0020] Description: The ball mill can mix the two powders evenly and grind them into fine particles of the required size to achieve more uniform alloying and improve the mechanical properties and corrosion resistance of the alloy material.

[0021] Furthermore, in step S1, the pressing parameters of the press are: pressure of 180-250 MPa, and pressure holding time of 2-10 min.

[0022] Note: If the parameter is too large, it may cause delamination of the blank; if the parameter is too small, the density cannot meet the requirements.

[0023] Furthermore, in step S3, the temperature of the solution treatment is 600-900°C, the heating time is 1-2h, the holding time is 0.5-2h, and the solution is cooled by quenching.

[0024] Description: Solution treatment can improve the mechanical properties of materials, increase the hardness, strength, toughness and wear resistance of alloys; and can make solute atoms evenly distributed in the matrix lattice, reduce the electrochemical reaction between grain boundaries and precipitates, and improve the corrosion resistance of alloys; and solution treatment can eliminate or reduce the precipitated phase in the material, reduce the phase change and grain boundary corrosion of the alloy at high temperature, and improve the thermal stability of the alloy.

[0025] Furthermore, in step S3, the temperature of the aging treatment is 400-500°C, the heating time is 0.5-1h, the heat preservation time is 1.5-2h, and the furnace is cooled.

[0026] Description: Aging treatment can improve the strength and hardness of alloy materials, improve the corrosion resistance of alloys, reduce the organizational and structural defects in alloy materials, and improve the stability of alloys.

[0027] Furthermore, in step S1, the blank is subjected to grain refinement treatment, including the following steps:

[0028] First, the blank is immersed in a grain growth inhibition liquid at 40 to 50° C. for 2 to 3 hours, and a step-by-step ultrasonic treatment is applied during the immersion process. After the immersion is completed, it is washed with deionized water for 2 to 5 times;

[0029] After cleaning, the blank is vacuum dried first, and then preheated to 250-280°C. The upper and lower surfaces of the blank are connected with a pulse width of 18-20 μm, a frequency of 100-2000 Hz, and a current density of 300-2000 A / mm 2 The electric pulse treatment lasts for 8 to 10 minutes;

[0030] Wherein, the vacuum drying temperature is 110-120° C., the vacuum degree is 8-10 Pa, and the drying time is 20-25 min.

[0031] Description: Soak the blank in the grain growth inhibitory liquid first to inhibit the activity of the grains and prevent the second phases of chromium and niobium from affecting the composition and uneven distribution of the alloy during rapid hot pressing sintering; applying ultrasonic treatment during soaking can not only accelerate the flow of the grain growth inhibitory liquid, enhance the diffusion effect, and help eliminate the holes and other defects of the alloy; it can also accelerate the growth inhibition effect of the grain growth inhibitory liquid on the grains in the blank;

[0032] High-energy pulse treatment after immersion can reduce the internal stress of the blank, refine the grain size of the blank, thereby improving the ductility of the alloy and providing a better foundation for rapid hot pressing sintering.

[0033] Furthermore, the step-by-step ultrasonic treatment is as follows: the ultrasonic power is 350-400W in the stage accounting for 1 / 3 to 1 / 2 of the total immersion time, the ultrasonic power is 450-500W in the stage accounting for 2 / 3 to 5 / 6 of the total immersion time, and the ultrasonic power is 550-600W in the last stage accounting for 1 / 6 of the total immersion time.

[0034] Description: Step-by-step enhanced ultrasonic treatment applies ultrasonic energy in a gradually increasing manner, which can avoid the adverse effects of excessive treatment or excessive ultrasonic energy on the alloy, protect the structure and performance of the alloy, and improve the alloy's antioxidant properties; because the step-by-step enhanced ultrasonic treatment gradually increases the ultrasonic energy, it can promote the inhibition liquid to penetrate the interior of the alloy better and more evenly. This helps to penetrate into the microstructure of the material, remove internal defects, impurities and bubbles, and improve the uniformity, quality and performance of the alloy.

[0035] Furthermore, the grain growth inhibiting liquid is a 10-12 g / L titanium fluoride solution.

[0036] Description: The grain growth inhibition liquid containing titanium can effectively reduce the grain growth rate of chromium, because titanium can form a stable compound with chromium, thereby inhibiting the diffusion and grain growth of chromium. And the addition of titanium can improve the oxidation resistance and corrosion resistance of copper-chromium-tellurium alloy.

[0037] The beneficial effects of the present invention are:

[0038] (1) The present invention uses Cr2Nb powder and electrolytic Cu powder as raw materials, and uses rapid hot pressing sintering to prepare a new CuCrNb alloy. The sintering temperature is low, the heating rate is fast, and the sintering time is short. The surface activation and rapid sintering effect are used to achieve ultra-fast densification of CuCrNb, effectively inhibit the growth of Cr2Nb phase, and maintain the original microstructure and size of the atomized powder.

[0039] (2) The present invention performs solution aging treatment after rapid hot pressing sintering, and the prepared CuCrNb has the characteristics of fine and uniform structure, large quantity and stability, which essentially improves the performance of CuCrNb. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is the metallographic diagram of the CuCrNb alloy prepared in Example 1. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below in conjunction with specific implementation methods to better reflect the advantages of the present invention.

[0042] Example 1

[0043] A method for preparing a CuCrNb alloy by rapid hot pressing sintering comprises the following steps:

[0044] S1. Pressing and forming:

[0045] Cr2Nb powder and electrolytic Cu powder are mixed in a mass ratio of 1:1, and the Cr2Nb powder and the electrolytic Cu powder are ball-milled in a high-speed ball mill at a rotation speed of 300 r / min for 4 hours to obtain a mixed powder; wherein the Cr2Nb powder comprises, by mass percentage, 54.0% Cr and 46.0% Nb;

[0046] The mixed powder is then pressed into a blank with a density of 80% by a press, and the pressing parameters of the press are: a pressure of 210 MPa and a pressure holding time of 6 minutes;

[0047] The preparation method of the Cr2Nb powder comprises the following steps:

[0048] The Cr block and the Nb block were placed in a CaO crucible according to the mass ratio for vacuum induction melting: nitrogen was filled into the melting furnace, and melting began when the pressure in the furnace reached 0.015 MPa, the heating rate was 10 kW / min, the melting power was 300 kW, and Cr2Nb alloy was prepared;

[0049] The Cr2Nb alloy is subjected to vacuum gas atomization treatment in an argon environment, the gas pressure is 2.5 MPa, the feed rate is 50 mm / min, and the cooling rate is 110 k / s to solidify to form Cr2Nb powder;

[0050] S2, rapid hot pressing sintering:

[0051] The blank obtained in step S1 is placed in a rapid hot pressing sintering furnace for sintering. First, the pressure is 0.8T, and the temperature is increased from room temperature to 725°C within 13 minutes, and the temperature is kept for 10 minutes; then the pressure is adjusted to 13T, and the temperature is increased to 925°C within 8 minutes, and the temperature is kept for 8 minutes to obtain a sintered alloy;

[0052] S3, solution aging treatment:

[0053] The sintered alloy obtained in step S3 is subjected to a solution aging treatment in a tubular furnace under an Ar gas protective atmosphere to obtain a CuCrNb alloy;

[0054] The temperature of the solution treatment is 750°C, the heating time is 1.5h, the holding time is 1.2h, and the treatment is quenched in water; the temperature of the aging treatment is 450°C, the heating time is 0.8h, the holding time is 1.8h, and the treatment is cooled in the furnace.

[0055] Example 2

[0056] The present embodiment is different from the embodiment 1 in that the Cr2Nb powder includes 56.0% Cr and 44.0% Nb by mass percentage.

[0057] Example 3

[0058] The difference between this embodiment and embodiment 1 is that the Cr2Nb powder includes 52.0% Cr and 48.0% Nb by mass percentage.

[0059] Example 4

[0060] The present embodiment is different from the embodiment 1 in that the Cr2Nb powder and the electrolytic Cu powder are ball-milled for 3.5 hours in a high-speed ball mill at a rotation speed of 280 r / min to obtain a mixed powder.

[0061] Example 5

[0062] The present embodiment is different from the embodiment 1 in that the Cr2Nb powder and the electrolytic Cu powder are ball-milled in a high-speed ball mill at a rotation speed of 320 r / min for 4.5 h to obtain a mixed powder.

[0063] Example 6

[0064] The difference between this embodiment and embodiment 1 is that a press is used to press the mixed powder into a blank with a density of 70%, and the pressing parameters of the press are: pressure of 180 MPa and pressure holding for 2 minutes.

[0065] Example 7

[0066] The difference between this embodiment and embodiment 1 is that a press is used to press the mixed powder into a blank with a density of 76%, and the pressing parameters of the press are: pressure of 250 MPa and pressure holding for 10 minutes.

[0067] Example 8

[0068] The difference between this embodiment and embodiment 1 is that the method for preparing the Cr2Nb powder comprises the following steps:

[0069] The Cr block and the Nb block were placed in a CaO crucible according to the mass ratio for vacuum induction melting: nitrogen was filled into the melting furnace, and melting began when the pressure in the furnace reached 0.01 MPa, the heating rate was 5 kW / min, the melting power was 270 kW, and Cr2Nb alloy was prepared;

[0070] The Cr2Nb alloy was subjected to vacuum gas atomization treatment in an argon environment with a gas pressure of 1.5 MPa and a feed rate of 30 mm / min, and solidified at a cooling rate of 100 k / s to form Cr2Nb powder.

[0071] Example 9

[0072] The difference between this embodiment and embodiment 1 is that the method for preparing the Cr2Nb powder comprises the following steps:

[0073] The Cr block and the Nb block were placed in a CaO crucible according to the mass ratio for vacuum induction melting: nitrogen was filled into the melting furnace, and melting began when the pressure in the furnace reached 0.02MPa, the heating rate was 15kW / min, the melting power was 330kW, and Cr2Nb alloy was prepared;

[0074] The Cr2Nb alloy was subjected to vacuum gas atomization treatment in an argon environment with a gas pressure of 4.0 MPa and a feed rate of 70 mm / min, and solidified at a cooling rate of 120 k / s to form Cr2Nb powder.

[0075] Example 10

[0076] The difference between this embodiment and embodiment 1 is that in step S2, first, the pressure is 0.5T, and the temperature is increased from room temperature to 600°C within 10 minutes, and kept warm for 5 minutes; then the pressure is adjusted to 10T, and the temperature is increased to 900°C within 5 minutes, and the temperature is kept warm for 5 minutes to obtain a sintered alloy.

[0077] Embodiment 11

[0078] The difference between this embodiment and embodiment 1 is that in step S2, first, the pressure is 1T, and the temperature is increased from room temperature to 850°C within 15 minutes, and kept warm for 15 minutes; then the pressure is adjusted to 15T, and the temperature is increased to 950°C within 510 minutes, and the temperature is kept warm for 10 minutes to obtain a sintered alloy.

[0079] Example 12

[0080] The difference between this embodiment and embodiment 1 is that, in step S3, the temperature of the solution treatment is 600°C, the heating time is 1 hour, the holding time is 0.5 hour, and quenching is performed; the temperature of the aging treatment is 400°C, the heating time is 0.5 hour, the holding time is 1.5 hour, and the furnace is cooled.

[0081] Example 13

[0082] The difference between this embodiment and embodiment 1 is that, in step S3, the temperature of the solution treatment is 900°C, the heating time is 2 hours, the holding time is 2 hours, and quenching is performed; the temperature of the aging treatment is 500°C, the heating time is 1 hour, the holding time is 2 hours, and the furnace is cooled.

[0083] Embodiment 14

[0084] The difference between this embodiment and embodiment 1 is that in step S1, the blank is subjected to grain refinement treatment, including the following steps:

[0085] First, the blank was immersed in a 45° C. grain growth inhibiting solution for 2.5 hours, wherein the grain growth inhibiting solution was a 11 g / L titanium fluoride solution, and a step-by-step ultrasonic treatment was applied during the immersion process. After the immersion was completed, the blank was washed with deionized water for 3 times.

[0086] The step-by-step ultrasonic treatment is as follows: the ultrasonic power is 380W in the stage accounting for 1 / 3 to 1 / 2 of the total immersion time, the ultrasonic power is 480W in the stage accounting for 2 / 3 to 5 / 6 of the total immersion time, and the ultrasonic power is 580W in the stage accounting for 1 / 6 of the total immersion time;

[0087] After cleaning, the blank is vacuum dried, and then preheated to 270°C and connected to the upper and lower surfaces of the blank with a pulse width of 19 μm, a frequency of 1000 Hz, and a current density of 1200 A / mm 2 The electric pulse treatment lasted for 9 minutes;

[0088] The vacuum drying temperature is 115° C., the vacuum degree is 9 Pa, and the drying time is 23 min.

[0089] Embodiment 15

[0090] The difference between this embodiment and embodiment 14 is that the blank is first immersed in a grain growth inhibition liquid at 40° C. for 2 hours, the grain growth inhibition liquid is a 10 g / L titanium fluoride solution, and a step-by-step ultrasonic treatment is applied during the immersion process. After the immersion is completed, the blank is washed twice with deionized water.

[0091] Example 16

[0092] The difference between this embodiment and embodiment 14 is that the blank is first immersed in a grain growth inhibition liquid at 50° C. for 3 hours, the grain growth inhibition liquid is a 12 g / L titanium fluoride solution, and a step-by-step ultrasonic treatment is applied during the immersion process. After the immersion is completed, the blank is washed with deionized water for 5 times.

[0093] Embodiment 17

[0094] The difference between this embodiment and Embodiment 14 is that the step-by-step ultrasonic treatment is as follows: the ultrasonic power is 350 W in the stage accounting for 1 / 3 to 1 / 2 of the total immersion time, the ultrasonic power is 500 W in the stage accounting for 2 / 3 to 5 / 6 of the total immersion time, and finally the ultrasonic power is 550 W in the stage accounting for 1 / 6 of the total immersion time.

[0095] Embodiment 18

[0096] The difference between this embodiment and Embodiment 14 is that the step-by-step ultrasonic treatment is as follows: the ultrasonic power is 400 W in the stage accounting for 1 / 3 to 1 / 2 of the total immersion time, the ultrasonic power is 450 W in the stage accounting for 2 / 3 to 5 / 6 of the total immersion time, and finally the ultrasonic power is 600 W in the stage accounting for 1 / 6 of the total immersion time.

[0097] Embodiment 19

[0098] The difference between this embodiment and embodiment 14 is that after cleaning, the blank is first vacuum dried at a temperature of 110°C, a vacuum degree of 8Pa, and a drying time of 20 minutes; and then the blank is preheated to 250°C.

[0099] Embodiment 20

[0100] The difference between this embodiment and embodiment 14 is that after cleaning, the blank is first vacuum dried at a temperature of 120°C, a vacuum degree of 10Pa, and a drying time of 25 minutes; and then the blank is preheated to 280°C.

[0101] Embodiment 21

[0102] The difference between this embodiment and embodiment 14 is that a pulse with a width of 18 μm, a frequency of 100 Hz, and a current density of 300 A / mm is connected to the upper and lower surfaces of the blank. 2 The electric pulse treatment lasted for 8 minutes.

[0103] Embodiment 22

[0104] The difference between this embodiment and embodiment 14 is that a pulse with a width of 20 μm, a frequency of 2000 Hz, and a current density of 2000 A / mm is connected to the upper and lower surfaces of the blank. 2 The electric pulse treatment lasted for 10 min.

[0105] Experimental example

[0106] For the CuCrNb alloy prepared in each embodiment, 5 samples of each embodiment were taken to test the performance of the CuCrNb alloy. The test results of the 5 samples of each embodiment were averaged as the test results of the embodiment. The specific exploration is as follows:

[0107] 1. Effect of Cr2Nb powder raw material ratio and preparation on the hardness and density of CuCrNb alloy.

[0108] Table 1 Physical and chemical properties of CuCrNb alloy of Example 1

[0109]

[0110] It can be seen from Table 1 that the CuCrNb alloy has excellent physical and chemical properties, low gas content, and combined Figure 1 It can be seen that the Cr2Nb grains are fine and evenly distributed in the structure.

[0111] Table 2 Hardness (HB) and density (g / cm2) of CuCrNb alloys in Examples 2-3, 8-9 3 )

[0112] Group Example 2 Example 3 Example 8 Example 9 hardness 78 80 75 79 density 8.1 8.3 7.7 8.1

[0113] It can be seen from the results in Tables 1 and 2 that too small or too large a proportion of niobium in the Cr2Nb powder and too small or too large a preparation parameter of the Cr2Nb powder will reduce the hardness and density of the CuCrNb alloy. Therefore, in general, the raw material ratio and preparation parameter effects of the Cr2Nb powder in Example 1 are better.

[0114] 2. Influence of preparation parameters of CuCrNb alloy on the hardness and density of CuCrNb alloy.

[0115] Table 2 Hardness (HB) and density (g / cm2) of CuCrNb alloys in Examples 4 to 7, 10 to 13 3 )

[0116]

[0117] It can be seen from the results in Table 2 that ball milling parameters that are too small or too large, pressing parameters that are too small or too large, and sintering parameters that are too small or too large will reduce the hardness and density of the CuCrNb alloy. The temperature of the solution aging treatment is higher and the holding time is longer. The hardness is improved compared with Example 1, but the density does not reach 8.8 of Example 1, and the improvement in hardness is small. The required temperature and holding time are higher and longer. Therefore, from an economic point of view, the parameter effect of Example 1 is relatively better.

[0118] 2. Influence of preparation parameters of CuCrNb alloy on the hardness and density of CuCrNb alloy.

[0119] Table 3 Hardness (HB) and density (g / cm2) of CuCrNb alloys in Examples 14 to 22 and Comparative Examples 1 to 3 3 )

[0120]

[0121] The difference between Control Example 1 and Example 14 is that no ultrasonic treatment is applied during the soaking process;

[0122] The difference between Control Example 2 and Example 14 is that the ultrasonic power of the ultrasonic treatment is kept constant at 480 W during the soaking process;

[0123] The difference between Control Example 3 and Example 14 is that no electric pulse treatment is performed after the soaking is completed;

[0124] From the results in Table 3, it can be seen that the control example 1 lacks ultrasonic treatment, the control example 2 lacks ultrasonic step change, and the control example 3 lacks electric pulse treatment. The hardness and density of the CuCrNb alloys of the comparative examples 1 to 13 are higher, but the improvement of the comparative examples 14 to 22 is reduced. Therefore, the steps of the examples 14 to 22 are more complete and the degree of optimization is higher;

[0125] By comparing Examples 14 to 22, it can be seen that if the immersion parameters are too small or too large, the step change of ultrasonic treatment is too small or too large, the vacuum drying parameters are too small or too large, and the electric pulse treatment parameters are too small or too large, they will reduce the improvement of the hardness and density of the CuCrNb alloy. Therefore, on the whole, the parameter effect of Example 14 is relatively optimal.

Claims

1. A method for preparing CuCrNb alloy by rapid hot pressing sintering, characterized in that: The following steps are involved: S1. Pressing and forming: Cr2Nb powder and electrolytic Cu powder are mixed in a mass ratio of 1:1 to obtain a mixed powder; wherein the Cr2Nb powder comprises, by mass percentage, 52.0-56.0% of Cr and 44.0-48.0% of Nb; The preparation method of the Cr2Nb powder comprises the following steps: The Cr block and the Nb block are placed in a CaO crucible according to the mass ratio for vacuum induction melting: nitrogen is filled into the melting furnace, and melting begins when the pressure in the furnace reaches 0.01-0.02 MPa, and the melting power is 270-330 kW, so as to prepare a Cr2Nb alloy; The Cr2Nb alloy is subjected to vacuum gas atomization treatment in an argon environment, the gas pressure is 1.5-4.0 MPa, the feed rate is 30-70 mm / min, and the cooling rate is 100-120 k / s to solidify to form Cr2Nb powder; The mixed powder is then pressed into a blank with a density of 70-80% by a press; The grain refinement treatment of the blank includes the following steps: First, the blank is immersed in a grain growth inhibition liquid at 40-50°C for 2-3 hours, and a step-by-step ultrasonic treatment is applied during the immersion process. After the immersion is completed, it is washed with deionized water for 2-5 times. After cleaning, the blank is vacuum dried first, and then preheated to 250~280℃, and then the upper and lower surfaces of the blank are connected with a pulse width of 18~20μm, a frequency of 100~2000Hz, and a current density amplitude of 300~2000A / mm 2 The electric pulse treatment lasts for 8 to 10 minutes; The vacuum drying temperature is 110-120°C, the vacuum degree is 8-10Pa, and the drying time is 20-25min. S2, rapid hot pressing sintering: The blank obtained in step S1 is placed in a rapid hot pressing sintering furnace for sintering. First, the pressure is 0.5-1T, and the temperature is increased from room temperature to 600-850°C within 10-15 minutes, and the temperature is kept for 5-15 minutes; then the pressure is adjusted to 10-15T, and the temperature is increased to 900-950°C within 5-10 minutes, and the temperature is kept for 5-10 minutes to obtain a sintered alloy; S3, solution aging treatment: The sintered alloy obtained in step S3 is subjected to a solution aging treatment in a tubular furnace under an Ar gas protective atmosphere to obtain a CuCrNb alloy.

2. The method for preparing CuCrNb alloy by rapid hot pressing sintering according to claim 1, characterized in that: In step S1, the mixing method of the mixed powder is: ball milling the Cr2Nb powder and the electrolytic Cu powder in a high-speed ball mill at a rotation speed of 280-320 r / min for 3.5-4.5 hours to obtain the mixed powder.

3. The method for preparing CuCrNb alloy by rapid hot pressing sintering according to claim 1, characterized in that: In step S1, the pressing parameters of the press are: pressure of 180-250 MPa, and pressure holding time of 2-10 min.

4. The method for preparing CuCrNb alloy by rapid hot pressing sintering according to claim 1, characterized in that: In step S3, the temperature of the solution treatment is 600-900°C, the heating time is 1-2h, the holding time is 0.5-2h, and the steel is quenched in water for cooling.

5. The method for preparing CuCrNb alloy by rapid hot pressing sintering according to claim 1, characterized in that: In step S3, the temperature of the aging treatment is 400-500°C, the heating time is 0.5-1h, the heat preservation time is 1.5-2h, and the furnace is cooled.

6. The method for preparing CuCrNb alloy by rapid hot pressing sintering according to claim 1, characterized in that: The step-by-step ultrasonic treatment is as follows: the ultrasonic power is 350-400W in the stage accounting for 1 / 3-1 / 2 of the total immersion time, the ultrasonic power is 450-500W in the stage accounting for 2 / 3-5 / 6 of the total immersion time, and the ultrasonic power is 550-600W in the last stage accounting for 1 / 6 of the total immersion time.

7. The method for preparing CuCrNb alloy by rapid hot pressing sintering according to claim 1, characterized in that: The grain growth inhibition liquid is a 10-12 g / L titanium fluoride solution.

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