Preparation method of high-performance powder alloy as well as product and application of high-performance powder alloy

Abstract

The invention provides a preparation method of a high-performance powder alloy and a product and application thereof, and relates to the technical field of powder alloy materials. The preparation method comprises the steps that S1, metal raw material powder is added into a double-planet high-speed dispersion machine, then styrene butadiene rubber, sodium carboxymethyl cellulose and N-methyl pyrrolidone are added, the rotating speed of blades of the double-planet high-speed dispersion machine is 2000-2550 rpm, dispersion is conducted for 4-8 h, and a powder alloy blank with the viscosity being 8500-9500 cp is formed; s2, the powder alloy blank is conveyed to a warm isostatic press, pressing is conducted for 30-60 min under the pressure of 95-105 MPa, and a powder alloy pressed blank is obtained; and S3, vacuum hot pressing sintering is conducted in a vacuum hot pressing sintering furnace, the hot pressing pressure is kept to be 50-80 MPa in the sintering process, sintering is conducted through gradient heating, and the powder alloy is obtained. According to the preparation method, the bending strength, the porosity and the fracture toughness of an alloy product are remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of powder alloy materials, and in particular relates to a preparation method of a high-performance powder alloy and a product and application thereof. Background Art

[0002] Powder metallurgy is a process that uses metal powder (or a mixture of metal powder and non-metal powder) as raw material to form metal materials, composite materials and their products through forming and sintering.

[0003] The traditional powder metallurgy process mainly includes the following steps: first, powder mixing, various metal powders and additives (lubricants, etc.) are fully mixed according to the ratio and specific particle size distribution, and mixed and stirred into blanks in a powder mixer; then, they are loaded into the mold cavity and a certain pressure is applied to form a compact; finally, the compact is sintered.

[0004] At present, the powder mixing method used for iron-based powder alloys is mainly dry mixing. Chinese invention patent CN103394686A discloses a two-stage dry mixing method for powder metallurgy iron-based mixed powder, including the following steps: (1) weighing iron powder, alloy powder, graphite powder, lubricant and adhesive according to the requirements of iron-based mixed powder; (2) adding the weighed iron powder, alloy powder, graphite powder and adhesive into the 1# mixer and mixing for 10min-20min; (3) placing the materials in the 1# mixer into the 1# transfer bin; (4) evenly spreading them on the heating furnace. On the steel belt, stay in the high temperature area of ​​the heating furnace at 140℃-200℃ for 2min-10min; (5) The temperature of the material coming out of the cooling area of ​​the heating furnace drops below the melting point of the lubricant and enters the 2# transfer bin through the belt conveyor; (6) Then enter the 2# mixer and add the lubricant; (7) Start the 2# mixer and run it for 15min-30min; (8) The material is placed in the 3# transfer bin; (9) Screening and packaging to obtain qualified iron-based mixed powder. This method is cumbersome and increases the risk of impurity contamination. In addition, after the powder material is heated and cooled, part of the iron-based powder is oxidized, affecting the purity and performance of the final powder material.

[0005] The powder mixing method used for cobalt-based cemented carbide is mainly wet grinding. Chinese invention patent CN111088445A discloses a method for preparing cemented carbide by wet grinding, wherein cobalt powder, chromium carbide powder and tungsten carbide powder are mixed and wet-grinded in a ball mill, the speed of the ball mill is 30-50r / min; the grinding time is 40-60h, and the wet grinding medium is selected from anhydrous alcohol or acetone; the mixed powder after wet grinding is dried, formed, sintered and cooled to obtain cemented carbide. The powder after wet grinding in this method needs to be dried to remove the liquid medium, which increases energy consumption and cost, and has low efficiency.

[0006] Hot isostatic pressing (HIP) is generally used in the powder alloy sintering stage. Chinese invention patent CN110666175A discloses a hot isostatic pressing method for nickel-based high-temperature alloy powder disks, in which the powder is placed in a package under vacuum conditions and sealed and then hot isostatically pressed to obtain an alloy material of the desired shape. This method has the following defects: (1) Highly active powders such as titanium alloys and nickel-based high-temperature alloys are prone to surface oxidation during hot isostatic pressing, which reduces the mechanical properties of the product; (2) The original particle boundaries (PPBs) will be retained during hot isostatic pressing, affecting the overall performance of the component; (3) In order to maintain its pressure during hot isostatic pressing, argon and nitrogen are generally used as pressurizing media, but these gases have poor thermal conductivity and there is temperature segregation in the furnace chamber, resulting in temperature differences in different parts of the alloy, affecting the performance of the product.

[0007] In summary, the existing technology mainly prepares powder alloys through dry mixing, wet grinding, HIP and other processes. The process is relatively complicated, the prepared alloy has insufficient density, is easily contaminated by impurities, and the mechanical properties of the material still need to be improved. Summary of the invention

[0008] The present invention aims at the problems existing in the prior art and provides a method for preparing a high-performance powder alloy, its products and applications. In the alloy powder mixing process, the present invention utilizes the pressure and shear force of the simultaneous revolution and rotation of the paddles of the double planetary high-speed disperser to subject the material to strong shearing and kneading, and the metal powder, adhesive and forming agent are mixed, extruded and sheared to obtain a uniform powder alloy blank; then, through the extrusion of a warm isostatic press, the excess adhesive, thickener, solvent and discrete metal particles in the slurry are filtered out to obtain a compact alloy blank, and the original particle boundaries (PPBs) in the blank are removed; the warm isostatic press uses liquid and a circulating water tank as a pressurizing medium to ensure that the temperature of the material in all directions remains consistent, overcoming the shortcomings of the hot isostatic pressing process; finally, the blank is sent to a hot pressing sintering furnace for sintering, and a high-performance powder alloy is obtained after cooling.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0010] First, the present invention provides a method for preparing a high-performance powder alloy, comprising the steps of:

[0011] S1. Add the metal raw material powder into a double planetary high-speed disperser, then add the adhesive, thickener and solvent, control the paddle speed of the double planetary high-speed disperser to 2000-2550rpm, and disperse for 4-8h to form a powder alloy billet with a viscosity of 8500-9500cp;

[0012] The adhesive is styrene-butadiene rubber (SBR), the thickener is sodium carboxymethyl cellulose (CMC), and the solvent is nitrogen-methyl pyrrolidone (NMP);

[0013] S2, sending the powder alloy blank to a warm isostatic press, the working pressure of the warm isostatic press is 95-105MPa, and the pressing time is 30-60min to obtain a powder alloy compact;

[0014] S3. Send the powder alloy compact into a vacuum hot pressing sintering furnace for vacuum hot pressing sintering. During the sintering process, the hot pressing pressure is maintained at 50-80 MPa, and the sintering is performed by gradient temperature increase to obtain a powder alloy.

[0015] In the present invention, the type, amount and particle size of the metal raw material powder for preparing the powder alloy are not particularly limited and can be within the scope of the present field.

[0016] In a preferred embodiment, the metal raw material powder includes the following components, calculated by mass fraction: V powder 9.5-15.5%, graphite powder 2.3-3.0%, Cr3C2 powder 5.0-15.5%, Mo powder 2.0-2.5%, Co powder 2.0-3.0%, Nb powder 2.8-3.5% and the remainder Fe powder.

[0017] In a preferred embodiment, the metal raw material powder includes the following components by mass fraction: 10% V powder, 2.5% graphite powder, 15% Cr3C2 powder, 2.25% Mo powder, 2.5% Co powder, 3.0% Nb powder and the balance Fe powder.

[0018] In a preferred embodiment, the particle sizes of the metal raw material powders are: V powder 2.0-2.5 μm, graphite powder 3.0-5.0 μm, Cr3C2 powder 2.0-2.6 μm; Mo powder 2.3-2.8 μm, Co powder 2.0-2.6 μm, Nb powder particle size 2.3-2.8 μm, Fe powder 2.5-3.2 μm. Metal raw materials within the above particle size range can achieve the technical effects described in the present invention.

[0019] Preferably, in step S1, the rotation speed of the double planetary high-speed disperser blades is 2500 rpm.

[0020] Preferably, in step S1, the dispersion time is 6 hours.

[0021] Preferably, in step S1, the viscosity of the powder alloy blank is 9000cp.

[0022] Preferably, in step S1, the mass ratio of the styrene-butadiene rubber, sodium carboxymethyl cellulose and nitrogen-methyl pyrrolidone is 3:1-3:4-6.

[0023] Further preferably, in step S1, the mass ratio of the styrene-butadiene rubber, sodium carboxymethyl cellulose and nitrogen-methyl pyrrolidone is 3:2:5.

[0024] Preferably, in step S1, the solid content of the powder alloy blank is 83.5-86.5%.

[0025] Further preferably, in step S1, the solid content of the powder alloy blank is 85-86%.

[0026] Preferably, in step S2, the working pressure of the warm isostatic press is 98-103 MPa, the working temperature is 190-210° C., and the pressing time is 30-60 min.

[0027] Further preferably, in step S2, the working pressure of the warm isostatic press is 99-101 MPa, the working temperature is 205° C., and the pressing time is 45 min.

[0028] More preferably, in step S2, the working pressure of the warm isostatic press is 100 MPa.

[0029] Preferably, in step S3, the gradient heating process is: firstly, heating from room temperature to 350-400°C at a heating rate of 15-20°C / min, and keeping warm for 40-50min; then, heating to 900-950°C at a heating rate of 10-15°C / min, and keeping warm for 50-70min.

[0030] Further preferably, in step S3, the gradient heating process is: firstly heating from room temperature to 380°C at a heating rate of 15°C / min, and keeping warm for 45 minutes; then heating to 950°C at a heating rate of 15°C / min, and keeping warm for 60 minutes.

[0031] Preferably, in step S3, the vacuum degree of the vacuum hot pressing sintering furnace is 0.05-0.1Pa.

[0032] In step S1 of the present invention, the double planetary high-speed disperser generates pressure and shear force through the high-speed rotation and revolution of the double planetary stirring blades, so that the materials undergo physical and chemical changes after mixing, extrusion, shearing and the like.

[0033] In step S2 of the present invention, the warm isostatic press is used to mold and press the powder material by sending the powder alloy blank to the jacket mold of the warm isostatic press, and the mesh diameter of the jacket mold is 1.8-2μm; after the above treatment, most of the solvent and discrete metal particles in the powder alloy blank are filtered out to obtain a dense and uniform powder alloy compact.

[0034] In step S3 of the present invention, after sintering is completed, the product is cooled to room temperature in the furnace to obtain a powder alloy of a desired size.

[0035] In the present invention, the powder alloy has a porosity of less than 0.1%, a bending strength of 4800-4950 MPa, an elastic modulus of 400-420 GPa, and a fracture toughness (KIC) of 45-48 MPa·m 1 / 2 .

[0036] Then, the present invention provides a high-performance powder alloy prepared by the above preparation method.

[0037] Preferably, the powder alloy has a porosity of less than 0.1%, a flexural strength of 4800-4950 MPa, an elastic modulus of 400-420 GPa, and a fracture toughness of 45-48 MPa·m 1 / 2 .

[0038] Finally, the present invention provides the application of the high-performance powder alloy in the preparation of alloy materials, porous materials, refractory metal materials, magnetic materials, and metal ceramic materials.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. Compared with the traditional powder dry mixing / wet grinding and hot isostatic pressing sintering process, the present invention adopts double planetary high-speed dispersion, warm isostatic pressing combined with hot pressing sintering process. The powder particles undergo physical and chemical effects of mixing, extrusion and shearing, which significantly improves the thermodynamic stability of the alloy powder system. The various metallographic phases in the sintered powder alloy are evenly distributed, improving the bonding strength, thereby improving the bending strength and fracture toughness of the alloy product.

[0041] 2. The present invention uses specific types of adhesives, thickeners and solvents to more effectively wet the alloy powder, change the surface properties of the solid particles, reduce the surface energy of the powder, reduce the tendency of the powder particles to aggregate with each other, make the powder particles more uniformly coated, and further improve the bending strength, porosity and fracture toughness of the alloy product.

[0042] 3. Compared with the traditional wet grinding process, the present invention adopts a double planetary high-speed dispersion and mixing process to obtain a more stable and higher quality alloy product. The traditional wet grinding process usually takes 40-60 hours, while the dispersion process of the double planetary high-speed dispersion and mixing process of the present invention only takes 4-8 hours, which greatly shortens the preparation process and energy consumption of the alloy powder; in addition, the fully automated operation of raw material feeding (mixing of powder and adhesive and other components), stirring, dispersion and exhaust of the present invention improves the accuracy of the formula, which is conducive to the large-scale, high-quality and stable production of high-performance powder alloys.

[0043] 4. The present invention adopts a warm isostatic press and a hot pressing sintering furnace to replace the traditional hot isostatic press process. The warm isostatic press adopts a liquid medium and a circulating water tank as a pressurizing medium. Compared with the argon / nitrogen pressurizing medium of the hot isostatic press, the temperature field in the furnace cavity is more uniform; generally, the internal temperature field error of a hot isostatic press is ±5°C, and the internal temperature field of a warm isostatic press can reach ±0.5°C. The uniform temperature in the furnace cavity of the present invention can ensure that the material is uniformly heated under high pressure and high temperature conditions, so that the powder or sintered blank can be fully densified in all directions, thereby helping to reduce the porosity of the product, improve the overall density, ensure the uniform reaction of the material in a high pressure and high temperature environment, and improve the flexural strength, wear resistance, corrosion resistance and fatigue life of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is the microstructure of the powder alloy of Example 1.

[0045] Figure 2 This is the microstructure of the powder alloy of Example 2.

[0046] Figure 3 This is the microstructure of the powder alloy of Example 3. DETAILED DESCRIPTION

[0047] The following non-limiting examples can enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way. The following content is merely an exemplary description of the scope of the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, which should also fall within the scope of the present invention.

[0048] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those generally understood by those of ordinary skill in the art to which the present invention belongs.

[0049] The present invention is further described below by way of specific examples. Unless otherwise specified, the various chemical reagents used in the examples of the present invention are obtained through conventional commercial channels.

[0050] In the following examples, the styrene-butadiene rubber was purchased from Shenzhen Haodian Technology Co., Ltd., model number HD3201; the sodium carboxymethyl cellulose was purchased from Changshu Weiyi Technology Co., Ltd., model number C1002; and the nitrogen-methyl pyrrolidone was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., model number M100588.

[0051] In the following examples and comparative examples, the metal raw material powders used are: V powder particle size 2.0-2.5 μm, purchased from the Nonferrous Metals Research Institute; graphite powder particle size 3.0-5.0 μm, purchased from Qingdao Tianyuan Graphite Co., Ltd.; Cr3C2 powder particle size 2.0-2.6 μm, purchased from the Nonferrous Metals Research Institute; Mo powder particle size 2.3-2.8 μm, purchased from the Nonferrous Metals Research Institute; Co powder particle size 2.0-2.6 μm, purchased from the Nonferrous Metals Research Institute; Nb powder particle size 2.3-2.8 μm, purchased from the Nonferrous Metals Research Institute; Fe powder particle size 2.5-3.2 μm, purchased from the Nonferrous Metals Research Institute. The above components, products from different manufacturers have no significant effect on the effect.

[0052] The hardness, fracture toughness, bending strength and porosity of the high-performance powder alloy material prepared by the preparation method of the present invention are significantly improved.

[0053] Example 1

[0054] S1. Add metal raw material powders V powder, graphite powder, Cr3C2 powder, Mo powder, Co powder, Nb powder and Fe powder into a double planetary high-speed disperser through a powder feeding metering system in proportions of 10%, 2.5%, 15.0%, 2.25%, 2.5%, 3.0% and 64.75% respectively;

[0055] Adhesive styrene-butadiene rubber (SBR), thickener sodium carboxymethyl cellulose (CMC) and nitrogen-methyl pyrrolidone (NMP) solvent were added at the feed port in a mass ratio of 3:2:5 through a solvent feeding metering system, and the paddle speed was 2500 rpm for dispersion for 6 hours. The viscosity of the extruded powder blank was 9000 cp, and the solid content in the powder blank was 85.6%;

[0056] The mass ratio of metal raw material powder to adhesive, thickener and solvent is 90:3:2:5;

[0057] S2, sending the powder blank to a warm isostatic press, the mesh diameter of the jacket mold of the warm isostatic press is 2 μm, the working pressure of the warm isostatic press is 100 MPa, the working temperature is 205° C., the pressing time is 45 min, the temperature in the mold cavity is maintained at 205° C. during the pressing process, and the temperature is maintained for 2 hours after the pressing is completed, to obtain a powder alloy compact with a solid content of 98.8%;

[0058] S3. Place the powder alloy compact into a vacuum hot pressing furnace for vacuum hot pressing sintering. During the sintering process, the hot pressing pressure is maintained at 50 MPa, and the sintering is performed using a gradient temperature increase: first, the temperature is increased from room temperature to 380°C at a heating rate of 15°C / min, and kept warm for 45 minutes; then, the temperature is increased to 950°C at a heating rate of 15°C / min, and kept warm for 60 minutes; the entire process is carried out in a vacuum state, and the vacuum degree of the vacuum hot pressing furnace is controlled at 0.06 Pa. After the sintering is completed, the furnace is cooled to room temperature to obtain a powder alloy.

[0059] Figure 1 This is the microstructure of the powder alloy of Example 1.

[0060] Comparative Example 1

[0061] The comparative example uses the traditional dry mixing method, hot isostatic pressing and sintering process to prepare the powder alloy, specifically:

[0062] S1. Dry mixing method: Mix the metal raw material powder, adhesive, thickener and solvent according to the ratio described in step S1 of Example 1, put the above materials into the mixture and stir at 900 rpm for 3 hours to obtain a powder blank;

[0063] S2. Hot isostatic pressing: the powder blank is placed in a hot isostatic pressing furnace at a temperature of 1100°C and a pressure of 130 MPa, and the hot isostatic pressing is carried out for 4 hours to obtain a powder alloy compact;

[0064] S3, sintering: put the powder alloy compact into a vacuum sintering furnace for vacuum sintering, firstly, heat the temperature from room temperature to 380℃ at a rate of 15℃ / min, and keep it for 30min; then heat the temperature to 810℃ at a rate of 15℃ / min, and keep it for 30min; then heat the temperature to 1000℃ at a rate of 15℃ / min, and keep it for 40min. The whole process is carried out in a vacuum state, and the vacuum degree of the vacuum sintering furnace is controlled at 0.06Pa.

[0065] Example 2

[0066] S1. Add metal powders V powder, graphite powder, Cr3C2 powder, Mo powder, Co powder, Nb powder and Fe powder into a double planetary high-speed disperser through a powder feeding metering system in proportions of 10%, 2.5%, 15.0%, 2.25%, 2.5%, 3.0% and 64.75% respectively;

[0067] Adhesive styrene-butadiene rubber (SBR), thickener sodium carboxymethyl cellulose (CMC) and nitrogen-methyl pyrrolidone (NMP) solvent were added at the feed port in a mass ratio of 3:2:5 through a solvent feeding metering system, and the paddle speed was 2500 rpm for dispersion for 6 hours. The viscosity of the extruded powder blank was 9000 cp, and the solid content in the powder blank was 85.6%;

[0068] The mass ratio of metal raw material powder to adhesive, thickener and solvent is 90:3:2:5;

[0069] S2, sending the powder blank to a warm isostatic press, the mesh diameter of the jacket mold of the warm isostatic press is 2 μm, the working pressure of the warm isostatic press is 100 MPa, the working temperature is 205° C., the pressing time is 45 min, the temperature in the mold cavity is maintained at 205° C. during the pressing process, and the temperature is maintained for 2 hours after the pressing is completed, to obtain a powder alloy compact with a solid content of 98.8%;

[0070] S3, put the powder alloy compact into a vacuum hot pressing furnace for vacuum hot pressing sintering. During the sintering process, the hot pressing pressure is maintained at 65MPa. First, the temperature is raised from room temperature to 380℃ at a heating rate of 20℃ / min, and kept warm for 45min; then the temperature is raised to 930℃ at a heating rate of 10℃ / min, and kept warm for 60min. The whole process is carried out in a vacuum state, and the vacuum degree of the vacuum hot pressing furnace is controlled at 0.08Pa. After sintering, the furnace is cooled to room temperature to obtain a powder alloy.

[0071] Figure 2 This is the microstructure of the powder alloy of Example 2.

[0072] Comparative Example 2

[0073] The difference from Example 2 is that the parameter settings of step S2 are different, specifically:

[0074] Step S1: Same as in Example 2;

[0075] Step S2: The powder blank is sent to a warm isostatic press. The mesh diameter of the jacket mold of the warm isostatic press is 2 μm. The working pressure of the warm isostatic press is 950 MPa, the working temperature is 205°C, and the pressing time is 25 min. The temperature in the mold cavity is maintained at 205°C during the pressing process, and the temperature is maintained for 2 hours after the pressing is completed to obtain a powder alloy compact with a solid content of 95.8%.

[0076] Step S3: Same as Example 2.

[0077] Example 3

[0078] S1. Add metal raw material powders V powder, graphite powder, Cr3C2 powder, Mo powder, Co powder, Nb powder and Fe powder into a double planetary high-speed disperser through a powder feeding metering system at a ratio of 10%, 2.5%, 15.0%, 2.25%, 2.5%, 3.0% and 64.75% respectively;

[0079] Adhesive styrene-butadiene rubber (SBR), thickener sodium carboxymethyl cellulose (CMC) and nitrogen-methyl pyrrolidone (NMP) solvent were added at the feed port in a mass ratio of 3:2:5 through a solvent feeding metering system, and the paddle speed was 2500 rpm for dispersion for 6 hours. The viscosity of the extruded powder blank was 9000 cp, and the solid content in the powder blank was 85.6%;

[0080] The mass ratio of metal raw material powder to adhesive, thickener and solvent is 90:3:2:5;

[0081] S2, sending the powder blank to a warm isostatic press, the mesh diameter of the jacket mold of the warm isostatic press is 2 μm, the working pressure of the warm isostatic press is 100 MPa, the working temperature is 205° C., the pressing time is 45 min, the temperature in the mold cavity is maintained at 205° C. during the pressing process, and the temperature is maintained for 2 hours after the pressing is completed, to obtain a powder alloy compact with a solid content of 98.8%;

[0082] S3, put the powder alloy compact into a vacuum hot pressing furnace for vacuum hot pressing sintering. During the sintering process, the hot pressing pressure is maintained at 80MPa. First, the temperature is raised from room temperature to 380℃ at a heating rate of 20℃ / min, and kept at this temperature for 45min; then the temperature is raised to 900℃ at a heating rate of 15℃ / min, and kept at this temperature for 60min. The whole process is carried out in a vacuum state, and the vacuum degree of the vacuum hot pressing furnace is controlled at 0.1Pa. After sintering, the powder alloy is cooled to room temperature with the furnace to obtain a powder alloy.

[0083] Figure 3 This is the microstructure of the powder alloy of Example 3.

[0084] Comparative Example 3

[0085] The difference from Example 3 is that the parameter settings of step S1 are different, specifically:

[0086] S1. Add metal raw material powders V powder, graphite powder, Cr3C2 powder, Mo powder, Co powder, Nb powder and Fe powder into a double planetary high-speed disperser through a powder feeding metering system in proportions of 10%, 2.5%, 15.0%, 2.25%, 2.5%, 3.0% and 64.75% respectively;

[0087] The adhesive styrene-butadiene rubber, the thickener sodium carboxymethyl cellulose and the nitrogen methyl pyrrolidone solvent were added at the feed port in a mass ratio of 3:2:5 through a solvent feeding metering system, and the paddle speed was 1800 rpm for dispersion for 6 hours. The viscosity of the extruded powder blank was 8000 cp, and the solid content in the powder blank was 82.4%;

[0088] The mass ratio of metal raw material powder to adhesive, thickener and solvent is 90:3:2:5;

[0089] S2, sending the powder blank to a warm isostatic press, the mesh diameter of the jacket mold of the warm isostatic press is 2 μm, the working pressure of the warm isostatic press is 100 MPa, the working temperature is 205° C., the pressing time is 45 min, the temperature in the mold cavity is maintained at 205° C. during the pressing process, and the temperature is maintained for 2 hours after the pressing is completed, and a powder alloy compact with a solid content of 97.8% is obtained after pressing and drying;

[0090] S3, put the powder alloy compact into a vacuum hot pressing furnace for vacuum hot pressing sintering. During the sintering process, the hot pressing pressure is maintained at 80MPa. First, the temperature is raised from room temperature to 380℃ at a heating rate of 20℃ / min, and kept at this temperature for 45min; then the temperature is raised to 900℃ at a heating rate of 15℃ / min, and kept at this temperature for 60min. The whole process is carried out in a vacuum state, and the vacuum degree of the vacuum hot pressing furnace is controlled at 0.1Pa. After sintering, the powder alloy is cooled to room temperature with the furnace to obtain a powder alloy.

[0091] Example 4

[0092] S1. Add metal raw material powders V powder, graphite powder, Cr3C2 powder, Mo powder, Co powder, Nb powder and Fe powder into a double planetary high-speed disperser through a powder feeding metering system at a ratio of 9.5%, 2.3%, 5.0%, 2.0%, 3.0%, 3.5% and 74.7% respectively;

[0093] The adhesive styrene-butadiene rubber, the thickener sodium carboxymethyl cellulose and the nitrogen methyl pyrrolidone solvent were added to the feed port in a mass ratio of 3:1:6 through a solvent feeding metering system, and the paddle speed was 2000 rpm for dispersion for 8 hours. The viscosity of the extruded powder blank was 8500 cp, and the solid content in the powder blank was 83.5%;

[0094] The mass ratio of metal raw material powder to adhesive, thickener and solvent is 90:3:1:6;

[0095] S2, sending the powder blank to a warm isostatic press, the mesh diameter of the jacket mold of the warm isostatic press is 2 μm, the working pressure of the warm isostatic press is 99 MPa, the working temperature is 190° C., the pressing time is 60 min, the temperature in the mold cavity is maintained at 190° C. during the pressing process, and the temperature is maintained for 2 hours after the pressing is completed, to obtain a powder alloy compact with a solid content of 96.5%;

[0096] S3. Place the powder alloy compact into a vacuum hot pressing furnace for vacuum hot pressing sintering. During the sintering process, the hot pressing pressure is maintained at 80 MPa, and the sintering is performed using a gradient temperature increase: first, the temperature is increased from room temperature to 350°C at a heating rate of 15°C / min, and kept warm for 45 minutes; then, the temperature is increased to 950°C at a heating rate of 15°C / min, and kept warm for 60 minutes; the entire process is carried out in a vacuum state, and the vacuum degree of the vacuum hot pressing furnace is controlled at 0.06 Pa. After the sintering is completed, the furnace is cooled to room temperature to obtain a powder alloy.

[0097] Example 5

[0098] S1. Add metal raw material powders V powder, graphite powder, Cr3C2 powder, Mo powder, Co powder, Nb powder and Fe powder into a double planetary high-speed disperser through a powder feeding metering system according to the mass ratios of 15.5%, 3.0%, 15.5%, 2.5%, 2.0%, 2.8% and 58.7% respectively;

[0099] Adhesive styrene-butadiene rubber (SBR), thickener sodium carboxymethyl cellulose (CMC) and nitrogen-methyl pyrrolidone (NMP) solvent were added at the feed port in a ratio of 3:3:4 through a solvent feeding metering system, and the paddle speed was 2550 rpm for dispersion for 4 hours. The viscosity of the extruded powder blank was 9500 cp, and the solid content in the powder blank was 84.1%;

[0100] The mass ratio of metal raw material powder to adhesive, thickener and solvent is 90:3:3:4;

[0101] S2, sending the powder blank to a warm isostatic press, the mesh diameter of the jacket mold of the warm isostatic press is 2 μm, the working pressure of the warm isostatic press is 101 MPa, the working temperature is 210° C., the pressing time is 30 min, the temperature in the mold cavity is maintained at 210° C. during the pressing process, and the temperature is maintained for 2 hours after the pressing is completed, to obtain a powder alloy compact with a solid content of 96.1%;

[0102] S3. Place the powder alloy compact into a vacuum hot pressing furnace for vacuum hot pressing sintering. During the sintering process, the hot pressing pressure is maintained at 80 MPa, and the sintering is performed using a gradient temperature increase: first, the temperature is increased from room temperature to 380°C at a heating rate of 15°C / min, and kept warm for 45 minutes; then, the temperature is increased to 900°C at a heating rate of 15°C / min, and kept warm for 60 minutes; the entire process is carried out in a vacuum state, and the vacuum degree of the vacuum hot pressing furnace is controlled at 0.06 Pa. After the sintering is completed, the furnace is cooled to room temperature to obtain a powder alloy.

[0103] Comparative Example 4

[0104] The difference from Example 1 is that the adhesive in step S1 is ethylene-vinyl acetate copolymer (EVA, Japan Mitsui Dow) and the thickener is zinc stearate. The rest is the same as Example 1.

[0105] Comparative Example 5

[0106] The difference from Example 1 is that the mass ratio of styrene-butadiene rubber, sodium carboxymethyl cellulose and nitrogen-methyl pyrrolidone in step S1 is 5:2:3. The rest is the same as Example 1.

[0107] Comparative Example 6

[0108] Different from Example 1, the sintering parameters in step S3 are different, and no gradient heating and vacuum treatment are performed, specifically:

[0109] Step S1-Step S2: Same as Example 1;

[0110] S3. Put the powder alloy compact into a hot pressing furnace for hot pressing and sintering. During the sintering process, the hot pressing pressure is maintained at 50 MPa, and the temperature is increased from room temperature to 950°C at a heating rate of 15°C / min and kept for 105 minutes. The whole process is carried out in a vacuum state. After the sintering is completed, the compact is cooled to room temperature with the furnace to obtain a powder alloy.

[0111] Comparative Example 7

[0112] The difference from Example 1 is that the gradient heating parameter settings of step S3 are different, specifically:

[0113] Step S1-Step S2: Same as Example 1;

[0114] S3. The powder alloy compact is placed in a vacuum hot pressing furnace for vacuum hot pressing sintering. During the sintering process, the hot pressing pressure is maintained at 50 MPa, and the sintering is performed using a gradient temperature increase: first, the temperature is increased from room temperature to 950°C at a heating rate of 15°C / min, and kept warm for 60 minutes; then, the temperature is increased to 1440°C at a heating rate of 15°C / min, and kept warm for 45 minutes; the entire process is carried out in a vacuum state, and the vacuum degree of the vacuum hot pressing furnace is controlled at 0.06 Pa. After the sintering is completed, the furnace is cooled to room temperature to obtain a powder alloy.

[0115] Performance Testing

[0116] 1. Fracture toughness: Test method: "Test method for plane strain fracture toughness KIC of metallic materials" GB / T 4161-2007.

[0117] 2. Bending strength: Test method: "Bending test method for metallic materials" GB / T 232-2010.

[0118] 3. Elastic modulus: Test method: "Method for determination of rate jump of elastic modulus of metallic materials" GB / T 43112-2023.

[0119] 4. Porosity: Detection method: "Industrial Computer Tomography (CT) Detection Method for Porosity of Additively Manufactured Metal Parts" (Draft for Comments).

[0120] The performance test results of the powder alloys obtained in various embodiments and comparative examples are shown in Table 1.

[0121] Table 1

[0122]

[0123] The letters a, b, c, and d in Table 1 represent the results of significant differences: Comparative Example 1 Compared with Example 1, a P≤0.05; Comparative Example 2 is compared with Example 2, b P≤0.05; Comparative Example 3 compared with Example 3, c P≤0.05; Comparative Examples 4-7 are compared with Example 1, d P≤0.05.

[0124] The letters a, b, c, and d in Table 1 represent the results of significant differences: the same letters in different rows of the same column indicate no significant difference (P>0.05), and different letters indicate significant difference (P<0.05).

[0125] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a high performance powder alloy, characterized in that: Includes steps: S1. Add the metal raw material powder into a double planetary high-speed disperser, then add the adhesive, thickener and solvent, control the paddle speed of the double planetary high-speed disperser to 2000-2550rpm, and disperse for 4-8h to form a powder alloy billet with a viscosity of 8500-9500cp; The adhesive is styrene-butadiene rubber, the thickener is sodium carboxymethyl cellulose, and the solvent is nitrogen-methyl pyrrolidone; S2, sending the powder alloy blank to a warm isostatic press, the working pressure of the warm isostatic press is 95-105MPa, and the pressing time is 30-60min to obtain a powder alloy compact; S3. Send the powder alloy compact into a vacuum hot pressing sintering furnace for vacuum hot pressing sintering. During the sintering process, the hot pressing pressure is maintained at 50-80 MPa, and the sintering is performed by gradient temperature increase to obtain a powder alloy.

2. The preparation method according to claim 1, characterized in that: The metal raw material powder comprises the following components by mass fraction: 9.5-15.5% of V powder, 2.3-3.0% of graphite powder, 5.0-15.5% of Cr3C2 powder, 2.0-2.5% of Mo powder, 2.0-3.0% of Co powder, 2.8-3.5% of Nb powder and the balance of Fe powder; The particle sizes of the metal raw material powders are: V powder 2.0-2.5 μm, graphite powder 3.0-5.0 μm, Cr3C2 powder 2.0-2.6 μm; Mo powder 2.3-2.8 μm, Co powder 2.0-2.6 μm, Nb powder 2.3-2.8 μm, Fe powder 2.5-3.2 μm.

3. The preparation method according to claim 1, characterized in that: In step S1, the speed of the paddles of the double planetary high-speed disperser is 2500 rpm, and the dispersion time is 6 hours.

4. The preparation method according to claim 1, characterized in that: In step S1, the powder alloy blank has a viscosity of 9000 cp and a solid content of 83.5-86.5%.

5. The preparation method according to claim 1, characterized in that: In step S1, the mass ratio of the styrene-butadiene rubber, sodium carboxymethyl cellulose and nitrogen-methyl pyrrolidone is 3:1-3:4-6.

6. The preparation method according to claim 5, characterized in that: In step S1, the mass ratio of the styrene-butadiene rubber, sodium carboxymethyl cellulose and nitrogen-methyl pyrrolidone is 3:2:

5.

7. The preparation method according to claim 1, characterized in that: In step S2, the working pressure of the warm isostatic press is 98-103 MPa, the working temperature is 190-210° C., and the pressing time is 30-60 min.

8. The preparation method according to claim 1, characterized in that: In step S3, the process of gradient heating is: firstly, heating from room temperature to 350-400°C at a heating rate of 15-20°C / min, and keeping the temperature for 40-50min; then, heating to 900-950°C at a heating rate of 10-15°C / min, and keeping the temperature for 50-70min; In step S3, the vacuum degree of the vacuum hot pressing sintering furnace is 0.05-0.1Pa.

9. The high performance powder alloy prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The powder alloy has a porosity of less than 0.1%, a bending strength of 4800-4950 MPa, an elastic modulus of 400-420 GPa, and a fracture toughness of 45-48 MPa·m 1 / 2 .

10. Use of the high performance powder alloy according to claim 9 in alloy materials, porous materials, refractory metal materials, magnetic materials, and metal ceramic materials.

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