WO2020132881A1 - 一种金属材料的烧结致密化及晶粒尺寸控制方法 - Google Patents

一种金属材料的烧结致密化及晶粒尺寸控制方法 Download PDF

Info

Publication number
WO2020132881A1
WO2020132881A1 PCT/CN2018/123568 CN2018123568W WO2020132881A1 WO 2020132881 A1 WO2020132881 A1 WO 2020132881A1 CN 2018123568 W CN2018123568 W CN 2018123568W WO 2020132881 A1 WO2020132881 A1 WO 2020132881A1
Authority
WO
WIPO (PCT)
Prior art keywords
sintering
powder
temperature
density
grain
Prior art date
Application number
PCT/CN2018/123568
Other languages
English (en)
French (fr)
Inventor
章林
曲选辉
李星宇
董岩皓
秦明礼
王光华
龙莹
钟伟
Original Assignee
北京科技大学
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 北京科技大学 filed Critical 北京科技大学
Priority to US16/793,897 priority Critical patent/US11673196B2/en
Publication of WO2020132881A1 publication Critical patent/WO2020132881A1/zh

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/14—Treatment of metallic powder
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/10—Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/02—Compacting only
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/02—Compacting only
    • B22F3/04—Compacting only by applying fluid pressure, e.g. by cold isostatic pressing [CIP]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B22F3/1017—Multiple heating or additional steps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy

Definitions

  • the invention belongs to the technical field of powder metallurgy, and particularly provides a method for sintering densification and grain size control of metal materials.
  • Tungsten and molybdenum targets are important basic raw materials required by industries such as semiconductor large-scale integrated circuits, high-end displays, and solar photovoltaics, and are used to make electrodes, wiring metals, shielding metal materials, and barrier materials. Tungsten and molybdenum targets require high density and fine grain size to ensure the uniformity of the coating. Tungsten metal is also the most promising material facing the plasma first wall and spallation neutron source target.
  • the low temperature brittleness of tungsten has always been a bottleneck problem restricting the use of tungsten materials, and brittleness has also greatly increased the difficulty of preparing and processing complex shape tungsten products.
  • Increasing the plasticity of tungsten, lowering its ductile-brittle transition temperature, and improving the high-temperature mechanical properties of tungsten have always been important research directions of metal tungsten materials.
  • Refinement of tungsten grains can not only reduce the ductile-brittle transition temperature of tungsten, but also improve the high-temperature mechanical properties and thermal shock resistance of the material.
  • the self-diffusion coefficient is low, and the sintering performance is very poor.
  • the sintering of refractory metals usually raises the green body to the highest temperature (up to 1600-2300°C) according to a certain temperature increase system, and keeps the temperature at the highest temperature to obtain the highest density.
  • the sintering process there are strong grains Large tendency, especially accelerated grain growth in the later stage of densification.
  • high-purity refractory metals after the material purity is improved, due to the lack of second phase particles as the core of recrystallization nucleation, non-uniform grain growth is likely to occur after thermal deformation, resulting in serious mechanical properties, sputtering and other performance properties decline.
  • the preparation of fine-grained refractory metal usually uses nano-refractory metal powder as the raw material.
  • the nano-powder achieves a faster densification rate, but the grain growth rate is also very fast, and the sintered blank cannot maintain the original nano-crystalline structure.
  • the significant agglomeration of nanoparticles can lead to non-uniform growth of grains, greatly reducing the performance of refractory metals. It can be seen that the problems of densification and grain growth are the two biggest problems facing nano-powder sintering.
  • the other is the addition of nano-second phase oxides (La 2 O 3 , Y 2 O 3 , ZrO 2 ) or carbides (TiC, ZrC, HfC).
  • the nano particles are evenly dispersed into the matrix to limit the grain boundaries and dislocations Migration, which suppresses the growth of grains and plays a role in refining grains. It can also significantly increase the room temperature and high temperature strength, high temperature stability and recrystallization temperature of refractory metals, but the addition of the second phase will reduce refractory Densification rate of metal products.
  • the present invention is a sintering process of refractory metal powder based on pressureless sintering, which utilizes the difference in grain boundary diffusion and grain boundary migration dynamics to suppress the growth of crystal grains in the final stage.
  • the raw material powder is first pretreated, and tungsten agglomerates are prepared by spray granulation, followed by pressing and cold isostatic pressing, and then a two-step sintering process is used to prepare high Density fine grain refractory metal.
  • the first step of sintering is to quickly heat the compact to a higher temperature T 1 , and then immediately reduce the temperature to a lower temperature T 2 after holding it for a short time, and then hold it at a low temperature T 2 for a longer time.
  • the key to the selection of the sintering temperature T1 in the first step is to control the density of the refractory metal body to 75-85%, and to have a fine and uniform pore structure.
  • the powder with uneven original particle size will be roughened to a certain extent, the particle size of the powder will be consistent, and a pore structure with uniform pore size will be formed, and the pore will hinder the growth of subsequent grains.
  • a proper first-step sintering process can obtain a certain temperature window in the second-step sintering to obtain a highly dense metal without significant grain growth.
  • the advantage of this method is that it can produce ultra-fine-grained refractory metals that are nearly fully dense without grain growth.
  • the two-step sintering method can greatly reduce the sintering temperature.
  • the first-step sintering temperature is 300-500°C lower than the conventional sintering temperature, which reduces energy consumption and can inhibit grain boundary migration or grain growth, but does not inhibit grain boundary diffusion.
  • the migration of grain boundaries is suppressed, while maintaining the activity of grain boundary diffusion. Therefore, the grains will not grow obviously, and play a role in "freezing" the grain structure. Although the kinetics of densification is slow at this stage, it is enough to obtain a high density of the green body.
  • the sintering temperature is lower, and the grain boundary diffusion and long-term heat preservation are used to eliminate the pores in the green body and increase the density without obvious grain growth. Because this method uses pressureless sintering, it solves the accelerated growth of grains in the final stage of the traditional sintering process of refractory metals, and can obtain sub-micron grains, which helps to improve the uniformity of grains and suppress abnormal grain growth .
  • the fine grain effectively improves the mechanical properties of tungsten and molybdenum materials and expands the scope of their use. It is a low-cost method for preparing fine-grain refractory metals, and is also applicable to other metal materials.
  • the technical problem to be solved by the present invention is to provide a method for sintering densification and grain size control of metal materials.
  • the technical problem to be solved is that the existing tungsten metal sintered products are difficult to densify, the grain size is difficult to control and the structure uniformity is poor And lead to the problem of low mechanical properties.
  • the present invention solves the above technical problems through the following technical solutions: First, a high-speed spiral blade mixer is used to deagglomerate the nano/sub-micron refractory metal powder raw material, and then spray granulation is used to obtain good filling and flow Shaped powder. Next, high-pressure pressing and cold isostatic pressing were used twice to achieve a higher green density and improve the uniformity of the green. Finally, through the two-step sintering process, the accelerated grain growth of the refractory metal powder in the later stage of sintering is suppressed, and the tungsten green body is fully densified at low temperature, and the grain growth is effectively controlled, and the pure tungsten product finally prepared It has the characteristics of high density, small grains and high thermodynamic properties.
  • the deagglomerated powder is spray granulated to improve the powder flow performance and compact density uniformity, nearly spherical granulated powder; the nearly spherical granulated powder is subjected to high pressure pressing and cold isostatic pressing to obtain a compact;
  • the green compact undergoes two-step pressureless sintering, that is, the first step of sintering is to quickly heat the green compact, hold it for a short time, control the density to 75-85%, and then lower the temperature, and then hold it again for a long time to further eliminate the residual pores. That is to obtain high-density fine-grained metal.
  • a high-speed spiral blade mixer is used to deagglomerate the raw material powder.
  • the rotational speed of the blade is 2000-3000 rpm, and the crushing time is 0.5-2 hours.
  • the binder and deionized water are uniformly mixed to make a solution A, and the binder content in the solution A is 5-15wt.%;
  • step 1 add the deagglomerated raw material powder to solution A in step 1 and mechanically stir until it is uniformly mixed to make a slurry; use a centrifugal spray dryer to spray granulate the resulting slurry with a rotational speed range of 8000-15000r/ min, atomization pressure is 100-300kPa, drying temperature is 90-150°C;
  • the processing temperature is 550-700°C
  • the heating rate is 5-10°C/min
  • the holding time is 60-120min.
  • the granulated powder is subjected to high-pressure compression molding, with a compression pressure of 700-1000 MPa and a holding time of 0.5-1.5 min, to obtain a preformed green body, which is placed in a jacket mold and subjected to cold isostatic pressing.
  • the cold isostatic pressure is 200-280MPa, and the holding time is 5-10min.
  • the first step of sintering is to heat the formed blank prepared by S3 to a temperature T 1 at a certain temperature increase rate, perform one-step heat preservation to obtain a sintered blank; then perform the second step of sintering: sintering the green body on the basis of T 1 at a rate cooled to a temperature T 2, incubated for two steps, i.e., to obtain a final ultra-fine grain metal, wherein, T 2 50-250 deg.] C lower than T 1, step length is less than two o'clock insulation The duration of step heat preservation.
  • the metal powder in S1 includes a refractory metal; the particle size of the deagglomerating powder is less than 0.5 ⁇ m.
  • the binder in S2 is polyvinyl alcohol, polyethylene glycol, stearic acid or paraffin; the solid content in the slurry is 60-85 wt.%.
  • the relative density of the shaped blank in S3 is greater than 50%.
  • the first step in S4 is sintering, the shaped body is sintered in a hydrogen atmosphere, the heating rate is 5°C/min and heated to T 1 , T 1 is 1200-1500°C, and the holding time is 1-2h.
  • the protective atmosphere is a hydrogen or argon atmosphere
  • the temperature is reduced from T 1 to T 2
  • the temperature reduction rate is 15-25° C./min
  • the holding time is 10-60 h.
  • the density of the primary sintered body is 75-85%, the grain size is 0.5-1 ⁇ m, and the pore size and distribution are uniform.
  • the density of the ultrafine crystal metal is greater than 98%.
  • the grains did not grow significantly during the second sintering process.
  • the present invention has the following advantages:
  • the characteristics of the starting powder will also have a significant impact on the two-step sintering process. Since the powder used is nano- or sub-micron powder, the smaller the particles, the more likely to be irregular agglomeration and the formation of pores inside the agglomerates.
  • the high-speed rotating blade drives the refractory metal powder particles to rotate at high speed. The shear force of the blade and the high-speed collision between the powder particles are used to open the agglomerates in the nano powder.
  • the resulting powder particles have a narrower particle size distribution and better dispersion .
  • the agglomerates of nano-powders and the pores inside the grains formed during the sintering process are eliminated, and such pores are difficult to eliminate even by subsequent high-temperature sintering. At the same time, the abnormal growth of grains is greatly reduced, and the uniformity of grain distribution in the sintered blank is improved.
  • the granulated powder can significantly improve the fluidity of the powder particles during the forming process and the uniformity of the filled mold, which is beneficial to achieve a higher powder packing density and make the compact
  • the density distribution in different parts is even.
  • Cold isostatic pressing technology also improves the difference in density distribution in the formed body, which is conducive to uniform shrinkage of the slab during the sintering process, forming a pore structure with a uniform pore size in the one-step sintered body, which can effectively pin the migration of the grain boundary. It laid the foundation for further densification in the second sintering process.
  • the two-step sintering process can effectively inhibit the accelerated growth of grains in the late sintering process in traditional sintering processes, promote densification and reduce grain growth, and the prepared refractory metals can maintain high crystallinity while maintaining the crystallinity.
  • the fineness of the grains basically eliminates abnormally grown grains, and has a high uniformity of microstructure, which significantly improves the mechanical properties of refractory metals.
  • the protective atmosphere in the first sintering process is hydrogen
  • the atmosphere in the second sintering process is argon.
  • the use of hydrogen atmosphere has the effect of reducing and purifying, which can remove most of the impurity oxygen in the shaped blank, thereby promoting the process of densification.
  • an argon gas atmosphere is used, which can effectively remove the water vapor generated during the hydrogen reduction process, which suppresses the gas-phase transport mechanism that leads to grain coarsening, and thus plays a role in suppressing grain coarsening.
  • the two-step sintering process reduces the sintering temperature by 300-500°C, reducing energy consumption and cost.
  • This method is not limited to refractory metals such as tungsten and molybdenum, but also provides a new way for the preparation of other high-density fine-grained metal materials.
  • FIG. 1 is a process flow diagram of a method for densification and grain size control of a metal material of the present invention.
  • the first step of sintering is to quickly heat the green body to a higher temperature T 1 and keep it for a short time to obtain a compact with a porosity of 75-85% and uniform porosity, and then immediately reduce the temperature to a lower temperature T 2 for the first time.
  • Two-step sintering heat preservation for a longer time to further eliminate residual pores without grain growth.
  • NS in the figure represents ordinary sintering
  • TSS-I represents the first sintering of the two-step sintering
  • TSS-II represents the second sintering of the two-step sintering.
  • the sintering temperature T 1 of the two-step sintering is 300-500° C. lower than the sintering temperature T 0 of the common sintering, and the grains of the two-step sintering process do not grow significantly at the later stage of sintering.
  • Fig. 3 is a schematic diagram showing the effect of the powder accumulation state on sintering. Kingery and Francois first determined in 1967 that there was a critical coordination number Nc for the holes in the powder sintering process. Suppose a hole is surrounded by N grains, and N is related to the early accumulation state of the powder. Then, if a hole N ⁇ Nc (powder accumulation state is tight), the interface between the hole and the grain is concave to the hole, and the hole shrinks; if a hole N>Nc (powder accumulation state is loose), the interface is convex to the hole, and the hole grows .
  • Nc critical coordination number
  • Figure 4 is a schematic diagram of the pore structure of the sintered body during the two-step sintering process.
  • the pores are usually difficult to shrink in the late sintering, and further densification process in the late sintering will inevitably cause grain growth.
  • the grain growth rate of the traditional sintering method is often related to the grain boundary mobility. According to the Brook speed criterion, the relative speed of the movement between the hole and the grain boundary has an important effect on the growth rate of the grain.
  • the first case is when the grain boundary movement speed is faster than the hole movement speed, the grain boundary and the hole will decouple, that is, the grain boundary moves freely from the hole, which will cause the hole to stay in the grain and it is difficult to shrink or the grain is abnormal Grow up;
  • the second case is that the hole movement speed on the grain boundary is lower than the grain boundary movement speed but it is not uncoupled, the pinning of the hole controls the growth of the grain;
  • the third case is that the grain boundary movement speed is slower than the hole movement The speed and the movement of the grain boundaries control the grain growth. Unlike the first type of grain boundary free movement, the second and third cases are slow grain growth processes.
  • the mechanism of the two-step sintering is that the first step reaches a certain density at a higher temperature T 1 , that is, a closed hole is just formed.
  • T 1 a higher temperature
  • T 2 a lower temperature
  • the sintering driving force is provided so that the grain boundary movement speed is slower than the hole movement rate, and the three-node or four-node pores of the grain do not move, thereby achieving slow grain growth.
  • Figure 5 shows the SEM microstructure of pure tungsten with different sintering processes.
  • the original powder is pure tungsten powder with an average particle size of 50nm,
  • (a) is in the state of ordinary sintering (NS), and is kept under a hydrogen atmosphere at 1600°C for 2h, and the grain size is about 3 ⁇ m;
  • Step sintering state (TSS-I) holding for 1 hour under 1400°C hydrogen atmosphere, grain size is about 0.5 ⁇ m;
  • (c) is the second step state of two-step sintering (TSS-II), under 1400°C hydrogen atmosphere After holding for 1h, the temperature was lowered to 1250°C and kept under argon atmosphere for 10h.
  • the grain size was about 0.7 ⁇ m.
  • Figure 6 is the SEM microstructure of pure molybdenum with different sintering processes.
  • the original powder is pure molybdenum powder with an average particle size of 30nm, (a) is in the state of ordinary sintering (NS), and is kept under a hydrogen atmosphere at 1500°C for 2h, and the grain size is about 5 ⁇ m; (b) is the first step of two-step sintering One-step sintering state (TSS-I), heat preservation under hydrogen atmosphere at 1250°C for 2h, grain size is about 1.5 ⁇ m; (c) is the second step state of two-step sintering (TSS-II), hydrogen atmosphere at 1250°C The temperature was kept for 1h, followed by cooling to 1150°C for 40h in an argon atmosphere, and the grain size was about 2 ⁇ m.
  • TSS-I One-step sintering state
  • TSS-II second step state of two-step sintering
  • the invention provides a method for sintering densification and grain size control of metal materials.
  • the method specifically includes the following steps:
  • the deagglomerated powder is spray granulated to improve the powder flow performance and compact density uniformity, nearly spherical granulated powder; the nearly spherical granulated powder is subjected to high pressure pressing and cold isostatic pressing to obtain a compact;
  • the green compact undergoes two-step pressureless sintering, that is, the first step of sintering is to quickly heat the green compact, hold it for a short time, control the density to 75-85%, and then lower the temperature, and then hold it again for a long time to further eliminate the residual pores. That is to obtain high-density fine-grained metal.
  • a high-speed spiral blade mixer is used to deagglomerate the raw material powder.
  • the rotational speed of the blade is 2000-3000 rpm, and the crushing time is 0.5-2 hours.
  • the binder and deionized water are uniformly mixed to make a solution A, and the binder content in the solution A is 5-15wt.%;
  • step 1 add the deagglomerated raw material powder to solution A in step 1 and mechanically stir until it is uniformly mixed to make a slurry; use a centrifugal spray dryer to spray granulate the resulting slurry with a rotational speed range of 8000-15000r/ min, atomization pressure is 100-300kPa, drying temperature is 90-150°C;
  • the processing temperature is 550-700°C
  • the heating rate is 5-10°C/min
  • the holding time is 60-120min.
  • the granulated powder is subjected to high-pressure compression molding, with a compression pressure of 700-1000 MPa and a holding time of 0.5-1.5 min, to obtain a preformed green body, which is placed in a jacket mold and subjected to cold isostatic pressing.
  • the cold isostatic pressure is 200-280MPa, and the holding time is 5-10min.
  • the first step of sintering is to heat the formed blank prepared by S3 to a temperature T 1 at a certain temperature increase rate, and perform one-step heat preservation to obtain a sintered blank; then the second step of sintering: sintering the green body on the basis of T 1 at a rate cooled to a temperature T 2, incubated for two steps, i.e., to obtain a final ultra-fine grain metal, wherein, T 2 50-250 deg.] C lower than T 1, step length is less than two o'clock insulation Step heat preservation time (as shown in Figure 1).
  • the metal powder in S1 includes a refractory metal; the particle size of the deagglomerating powder is less than 0.5 ⁇ m.
  • the binder in the S2 is polyvinyl alcohol, polyethylene glycol, stearic acid or paraffin; the solid content in the slurry is 60-85wt.%.
  • the relative density of the shaped blank in S3 is greater than 50%.
  • the first step in S4 is sintering, and the shaped body is sintered in a hydrogen atmosphere, and the heating rate is 5°C/min and heated to T 1 , T 1 is 1200-1500°C, and the holding time is 1-2h.
  • the protective atmosphere is a hydrogen or argon atmosphere, and the temperature is reduced from T 1 to T 2 , the temperature reduction rate is 15-25° C./min, and the holding time is 10-60 h.
  • the density of the primary sintered body is 75-85%, the grain size is 0.5-1 ⁇ m, and the pore size and distribution are uniform.
  • the density of the ultrafine crystal metal is greater than 98%.
  • the high-speed spiral blade mixer is used to deagglomerate the raw material powder.
  • the rotation speed of the blade is 3000 rpm and the crushing time is 1 hour to obtain a deagglomerating raw material powder with a narrower particle size distribution.
  • Polyethylene glycol and deionized water were evenly mixed to make solution A.
  • the content of the binder in solution A was 15 wt.%.
  • the processing temperature is 700°C, the heating rate is 5°C/min, and the holding time is 120min, to obtain nearly spherical granulated powder;
  • the granulated powder is subjected to bidirectional compression molding with a pressing pressure of 1000 MPa and a holding time of 1 min to obtain a pre-formed green body.
  • the preformed green body is placed in a jacket mold for vacuum encapsulation, and then cold isostatic pressing is performed.
  • the cold isostatic pressing pressure is 280 MPa and the holding time is 5 minutes to obtain a shaped green body; the shaped green body is processed in a hydrogen atmosphere.
  • One-step sintering the sintering temperature is 1400°C, the heating rate is 15°C/min, and the holding time is 1h.
  • the temperature is quickly reduced to the second sintering temperature of 1250°C.
  • the sintering atmosphere is replaced with argon gas and the holding time is 10h.
  • high-density ultra-fine grain tungsten without grain growth is obtained.
  • the microstructure is shown in Figure 5, with a density of 98% and an average grain size of 0.7 ⁇ m.
  • the high-speed spiral blade mixer is used to deagglomerate the raw material powder.
  • the rotation speed of the blade is 3000 rpm and the crushing time is 1 hour to obtain a deagglomerating raw material powder with a narrower particle size distribution.
  • Polyethylene glycol and deionized water were evenly mixed to make solution A.
  • the content of the binder in solution A was 15 wt.%.
  • the processing temperature is 700°C, the heating rate is 5°C/min, and the holding time is 120min, to obtain nearly spherical granulated powder;
  • the granulated powder is subjected to bidirectional compression molding with a pressing pressure of 1000 MPa and a holding time of 1 min to obtain a pre-formed green body.
  • the preformed green body is placed in a jacket mold for vacuum encapsulation, and then cold isostatic pressing is performed.
  • the cold isostatic pressing pressure is 280 MPa and the holding time is 5 minutes to obtain a shaped green body; the shaped green body is processed in a hydrogen atmosphere.
  • One-step sintering the sintering temperature is 1300°C, the heating rate is 15°C/min, and the holding time is 1h.
  • the temperature was rapidly reduced to 1200°C in the second step sintering temperature at a rate of 20°C/min.
  • the sintering atmosphere was changed to argon gas, and the holding time was 20h.
  • high-density ultrafine crystalline tungsten without grain growth was obtained.
  • the density is 97% and the average grain size is 0.6 ⁇ m.
  • a high-speed spiral blade mixer was used to deagglomerate the raw material powder.
  • the rotation speed of the blade was 2500 rpm and the crushing time was 1 hour to obtain a deaggregated raw material powder with a narrower particle size distribution.
  • Polyethylene glycol and deionized water were evenly mixed to make solution A, and the binder content in solution A was 10 wt.%.
  • 200 nm of raw material tungsten powder was added to solution A and mechanically stirred until the mixture was uniformly prepared.
  • the solid content in the slurry is 70wt.%; the resulting slurry is spray-granulated using a centrifugal spray dryer, the rotating speed range is 12000r/min, the atomizing pressure is 200kPa, and the drying temperature is 120°C ; Put the granulated powder into a tube furnace and pass high-purity hydrogen for degreasing and reduction treatment.
  • the processing temperature is 600°C, the heating rate is 5°C/min, and the holding time is 120min, to obtain nearly spherical granulated powder;
  • the granulated powder was subjected to bidirectional compression molding, with a pressing pressure of 900 MPa and a holding time of 1 min to obtain a preformed green body.
  • the preformed green body is placed in a jacket mold for vacuum sealing, and then cold isostatic pressing is performed.
  • the cold isostatic pressing pressure is 250 MPa, and the holding time is 5 min.
  • a shaped green body is obtained; the shaped green body is processed in a hydrogen atmosphere.
  • One-step sintering the sintering temperature is 1400°C, the heating rate is 15°C/min, and the holding time is 1h.
  • the temperature was quickly reduced to the second sintering temperature of 1250°C at a rate of 20°C/min.
  • the sintering atmosphere was changed to argon gas and the holding time was 20h.
  • ultra-fine crystalline tungsten with high density and no grain growth was obtained. The density is 97% and the average grain size is 1.5 ⁇ m.
  • the high-speed spiral blade mixer is used to deagglomerate the raw material powder.
  • the blade rotation speed is 2000 rpm and the crushing time is 1 hour.
  • the deagglomerated raw material powder with a narrower particle size distribution is obtained.
  • Polyethylene glycol and deionized water were evenly mixed to make solution A, the binder content in solution A was 5wt.%, and then 400nm raw material tungsten powder was added to solution A and mechanically stirred until the mixture was uniformly prepared.
  • the solid content in the slurry is 65wt.%; the resulting slurry is spray-granulated using a centrifugal spray dryer, the rotating speed range is 10000r/min, the atomizing pressure is 150kPa, and the drying temperature is 140°C ; Put the granulated powder into a tube furnace and pass high-purity hydrogen for degreasing and reduction treatment.
  • the processing temperature is 550 °C, the heating rate is 5 °C/min, and the holding time is 120min, to obtain nearly spherical granulated powder;
  • the granulated powder was subjected to bidirectional compression molding with a pressing pressure of 700 MPa and a holding time of 1 min to obtain a preformed green body.
  • the preformed green body is placed in a cladding mold for vacuum sealing, and then cold isostatic pressing is performed.
  • the cold isostatic pressing pressure is 200 MPa and the holding time is 5 min to obtain a shaped green body; the shaped green body is subjected to the first step in a hydrogen atmosphere
  • One-step sintering the sintering temperature is 1400°C, the heating rate is 15°C/min, and the holding time is 1h.
  • the temperature was quickly reduced to 1300°C in the second step sintering temperature at a rate of 20°C/min.
  • the sintering atmosphere was replaced with argon gas and the holding time was 30h.
  • ultra-fine tungsten with high density and no grain growth was obtained. The density is 97% and the average grain size is 1.2 ⁇ m.
  • the high-speed spiral blade mixer is used to deagglomerate the raw material powder.
  • the rotation speed of the blade is 2000 rpm and the crushing time is 1 hour to obtain a deaggregated raw material powder with a narrower particle size distribution.
  • Polyethylene glycol and deionized water were evenly mixed to make solution A.
  • the binder content in solution A was 5 wt.%, and then 30 nm of raw material molybdenum powder was added to solution A and mechanically stirred until the mixture was uniformly prepared Slurry, the solid content in the slurry is 60wt.%; the resulting slurry is spray-granulated using a centrifugal spray dryer, the rotating speed range is 12000r/min, the atomizing pressure is 150kPa, and the drying temperature is 140°C ; Put the granulated powder into a tube furnace and pass high-purity hydrogen for degreasing and reduction treatment.
  • the processing temperature is 550 °C, the heating rate is 5 °C/min, and the holding time is 120min, to obtain nearly spherical granulated powder;
  • the granulated powder was subjected to bidirectional compression molding, with a pressing pressure of 700 MPa and a holding time of 2 min, to obtain a preformed green body.
  • the preformed green body is placed in a cladding mold for vacuum sealing, and then cold isostatic pressing is performed.
  • the cold isostatic pressing pressure is 200 MPa and the holding time is 5 min to obtain a shaped green body; the shaped green body is subjected to the first step in a hydrogen atmosphere
  • One-step sintering the sintering temperature is 1250°C, the heating rate is 15°C/min, and the holding time is 1h. Then at a rate of 20°C/min, the temperature was quickly reduced to the second sintering temperature of 1150°C. At this time, the sintering atmosphere was changed to argon and the holding time was 40h. Finally, ultra-fine grained molybdenum with high density and no grain growth was obtained.
  • the microstructure is shown in Figure 6, with a density of 97% and an average grain size of 2 ⁇ m.
  • the high-speed spiral blade mixer is used to deagglomerate the raw material powder.
  • the rotation speed of the blade is 2000 rpm and the crushing time is 1 hour to obtain a deaggregated raw material powder with a narrower particle size distribution.
  • Polyethylene glycol and deionized water were evenly mixed to make solution A.
  • the binder content in solution A was 5 wt.%, and then 30 nm of raw material molybdenum powder was added to solution A and mechanically stirred until the mixture was uniformly prepared Slurry, the solid content in the slurry is 60wt.%; the resulting slurry is spray-granulated using a centrifugal spray dryer, the rotating speed range is 12000r/min, the atomizing pressure is 150kPa, and the drying temperature is 140°C ; Put the granulated powder into a tube furnace and pass high-purity hydrogen for degreasing and reduction treatment.
  • the processing temperature is 550 °C, the heating rate is 5 °C/min, and the holding time is 120min, to obtain nearly spherical granulated powder;
  • the granulated powder was subjected to bidirectional compression molding, with a pressing pressure of 700 MPa and a holding time of 2 min, to obtain a preformed green body.
  • the preformed green body is placed in a cladding mold for vacuum sealing, and then cold isostatic pressing is performed.
  • the cold isostatic pressing pressure is 200 MPa and the holding time is 5 min to obtain a shaped green body; the shaped green body is subjected to the first step in a hydrogen atmosphere
  • One-step sintering, sintering temperature is 1350°C, heating rate is 15°C/min, no holding time.
  • the temperature was rapidly reduced to 1200°C in the second sintering temperature at a rate of 20°C/min.
  • the sintering atmosphere was replaced with argon gas and the holding time was 40h.
  • ultra-fine grained molybdenum with high density and no grain growth was obtained.
  • the density is 98% and the average grain size is 1.2 ⁇ m.
  • the high-speed spiral blade mixer is used to deagglomerate the raw material powder.
  • the blade rotation speed is 2000 rpm and the crushing time is 1 hour.
  • the deagglomerated raw material powder with a narrower particle size distribution is obtained.
  • Polyethylene glycol and deionized water were evenly mixed to make solution A.
  • the content of the binder in solution A was 5 wt.%.
  • 50 nm of raw material molybdenum powder was added to solution A and mechanically stirred until the mixture was uniformly prepared.
  • the solid phase content in the slurry is 60wt.%; the resulting slurry is spray-granulated using a centrifugal spray dryer, the rotating speed range is 10000r/min, the atomizing pressure is 150kPa, and the drying temperature is 140°C ; Put the granulated powder into a tube furnace and pass high-purity hydrogen for degreasing and reduction treatment.
  • the processing temperature is 550 °C, the heating rate is 5 °C/min, and the holding time is 120min, to obtain nearly spherical granulated powder;
  • the granulated powder was subjected to bidirectional compression molding, with a pressing pressure of 700 MPa and a holding time of 2 min, to obtain a preformed green body.
  • the preformed green body is placed in a cladding mold for vacuum sealing, and then cold isostatic pressing is performed.
  • the cold isostatic pressing pressure is 200 MPa and the holding time is 5 min to obtain a shaped green body; the shaped green body is subjected to the first step in a hydrogen atmosphere
  • One-step sintering, sintering temperature is 1350°C, heating rate is 15°C/min, no holding time. Then, the temperature was quickly reduced to 1550°C at the rate of 15°C/min, and the sintering atmosphere was changed to argon at this time, the holding time was 40h, and finally ultra-fine grained molybdenum with high density and no grain growth was obtained.
  • the density is 98% and the average grain size is 1.3 ⁇ m.
  • the high-speed spiral blade mixer is used to deagglomerate the raw material powder.
  • the rotation speed of the blade is 2000 rpm and the crushing time is 1 hour to obtain a deaggregated raw material powder with a narrower particle size distribution.
  • Polyethylene glycol and deionized water were evenly mixed to make solution A.
  • the binder content in solution A was 5 wt.%, and then 70 nm of raw material molybdenum powder was added to solution A and mechanically stirred until the mixture was uniformly prepared.
  • the solid content of the slurry is 60wt.%; the resulting slurry is spray-granulated using a centrifugal spray dryer, the rotating speed range is 8000r/min, the atomizing pressure is 150kPa, and the drying temperature is 140°C ; Put the granulated powder into a tube furnace and pass high-purity hydrogen for degreasing and reduction treatment.
  • the processing temperature is 550 °C, the heating rate is 5 °C/min, and the holding time is 120min, to obtain nearly spherical granulated powder;
  • the granulated powder was subjected to bidirectional compression molding, with a pressing pressure of 700 MPa and a holding time of 2 min, to obtain a preformed green body.
  • the preformed green body is placed in a cladding mold for vacuum sealing, and then cold isostatic pressing is performed.
  • the cold isostatic pressing pressure is 200 MPa and the holding time is 5 min to obtain a shaped green body; the shaped green body is subjected to the first step in a hydrogen atmosphere
  • One-step sintering the sintering temperature is 1250°C, the heating rate is 15°C/min, and the holding time is 2h.
  • the temperature was rapidly reduced to 25°C/min at the second sintering temperature of 1200°C.
  • the sintering atmosphere was changed to argon and the holding time was 40h.
  • ultra-fine grained molybdenum with high density and no grain growth was obtained.
  • the density is 97% and the average grain size is 1.8 ⁇ m.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Powder Metallurgy (AREA)

Abstract

一种金属材料的烧结致密化及晶粒尺寸控制方法，首先对原料粉末进行解团聚处理，得到分散性好的解团聚粉末；解团聚粉末进行喷雾造粒以提高粉末流动性能和压坯密度均匀性；造粒粉末进行高压压制和冷等静压成形；压坯经过两步无压烧结后得到高致密度细晶粒难熔金属。第一步烧结是将压坯快速升温至温度T 1，保温将致密度控制在75-85％，随后降温至温度T 2，进行长时间保温以进一步消除残余孔洞。两步烧结能够大幅度降低烧结温度，在较低温度下就能够实现金属坯体的近全致密化，而且能够有效抑制常规烧结过程中晶粒在致密化后期的快速长大，所制备的难熔金属制品接近全致密、晶粒细小且晶粒尺寸分布均匀、力学性能优异。

Description

一种金属材料的烧结致密化及晶粒尺寸控制方法 技术领域
本发明属于粉末冶金技术领域，特别提供了一种金属材料的烧结致密化及晶粒尺寸控制方法。
背景技术
难熔金属是国防、核工程、航天航空、电子、高端装备等特殊应用领域不可替代的关键材料。钨、钼靶材是半导体大规模集成电路、高端显示、太阳能光伏等产业所需的重要基础原材料，用于制作电极、布线金属、屏蔽金属材料、以及阻挡层材料等。钨、钼靶材要求具有高的致密度及细小的晶粒尺寸以保证镀膜的均匀性。金属钨还是最有希望的面向等离子体第一壁材料和散裂中子源靶。然而，钨的低温脆性一直是限制钨材料使用的瓶颈问题，脆性也大大增加了复杂形状钨制品制备加工的难度。提高钨的塑性，降低其韧脆转变温度，改善钨的高温力学性能一直是金属钨材料的重要研究方向。通过细化钨晶粒不仅可以降低钨的韧脆转变温度，还可以提高材料的高温力学性能和抗热冲击性能。然而，由于钨、钼的熔点高，自扩散系数较低，烧结性能很差。难熔金属的烧结通常是将坯体按照一定的升温制度升高到最高的温度(高达1600-2300℃)，并在最高温度保温来获得最高的密度，烧结过程中晶粒存在着强烈的长大倾向，特别是致密化后期晶粒加速长大。特别是对于高纯难熔金属，材料纯度提高后，由于缺少第二相质点作为再结晶形核核心，热变形后容易发生晶粒非均匀长大，导致材料力学性能、溅射等使用性能严重下降。目前制备细晶粒难熔金属的通常采用纳米难熔金属粉末为原料，由于纳米粉体的晶界能和表面活性能大，烧结的驱动力很大，一旦有外部条件的推动，粒子就会飞速长大，使得晶粒的尺 寸难以控制。为了抑制难熔金属晶粒的长大，常采用两种方法。一种是采用特殊烧结工艺，通过外力和辅助外场等工艺手段来实现抑制钨颗粒的长大。如热等静压、等离子体活化烧结、微波烧结、超高压力下通电烧结等。这些方法难以制备形状复杂的钨制品。在烧结的过程中，纳米粉末达到致密化速率较快，但是晶粒长大的速度也很快，烧结坯无法保持原来的纳米晶结构。此外，纳米颗粒显著的团聚现象会导致晶粒的非均匀长大，大幅度降低难熔金属的性能。可见，致密化问题和晶粒长大问题是目前纳米粉烧结面临的两个最大问题。另一种是添加纳米第二相氧化物(La 2O 3，Y 2O 3，ZrO 2)或碳化物(TiC，ZrC，HfC)，纳米颗粒均匀分散到基体中能够限制晶界和位错的迁移，从而抑制晶粒长大，起到细化晶粒的效果，还可以显著提高难熔金属的室温及高温强度、高温稳定性以及再结晶温度，但是第二相的添加会降低难熔金属制品的致密化速率。
本发明是一种基于无压烧结的难熔金属粉末烧结工艺，利用晶界扩散和晶界迁移动力学的差异来抑制最终阶段晶粒的长大。以纳米/亚微米级难熔金属粉末作为原料，首先对原料粉末进行预处理，并通过喷雾造粒制备钨团聚体，接着进行压制和冷等静压成形，然后采用两步烧结工艺来制备高致密度细晶粒难熔金属。第一步烧结是将压坯快速升温至一个较高的温度T 1，短时间保温后立即降温至较低温度T 2，然后在低温T 2下保温较长时间。第一步烧结温度T1选择的关键是将难熔金属坯体的致密度控制在75-85％，并且具有细小、均匀的孔隙结构。第一步烧结过程中，原始粒径不均匀的粉末会发生一定程度的粗化，粉末颗粒粒径趋于一致，并形成孔隙大小均匀的孔隙结构，孔隙对后续晶粒的长大具有阻碍作用，对第二步烧结过程中坯体的进一步致密化具有显著的影响，直接关系到最终坯体的致密度。合适的第一步烧结工艺才能在第二步烧结中获得一定的温度窗口，来获得高致密度的金属，而无明显的晶粒长大。该方法的 优点是能够制备出接近全致密而无晶粒长大的超细晶难熔金属。两步烧结法能够大幅度降低烧结温度，第一步烧结的温度比常规烧结温度低300-500℃，降低了能耗，能够抑制晶界迁移或晶粒生长，但是没有抑制晶界扩散。第二步烧结过程中晶界迁移受到抑制，而保持晶界扩散的活性。因此，晶粒不会发生明显的长大，对晶粒结构起到“冻结”的作用，此阶段虽然致密化动力学较慢，但是足以使坯体获得高的致密度。第二步烧结温度较低，利用晶界扩散和较长时间保温来消除坯体中的孔隙，提高致密度而无明显晶粒长大。由于该方法采用无压烧结，解决了难熔金属传统烧结过程中最后阶段晶粒的加速长大，而且可以获得亚微米晶粒，有助于提高晶粒的均匀性，抑制异常晶粒长大。能够制备出接近全致密的钨制品，致密度大于99％，而且能够实现难熔金属制品的近终成形。细晶粒有效提高了钨、钼材料的力学性能，扩大其使用范围。是一种低成本制备细晶难熔金属的方法，同样也适用于其他金属材料。
发明内容
本发明所要解决的技术问题是提供一种金属材料的烧结致密化及晶粒尺寸控制方法，要解决的技术问题是现有的钨金属烧结制品致密化困难、晶粒尺寸难以控制和组织均匀性差而导致其力学性能不高的问题。
本发明是通过下述技术方案来解决上述技术问题的：首先，采用高速螺旋叶片混合器对纳米/亚微米难熔金属粉末原料进行解团聚处理，然后通过喷雾造粒获得具有良好填充性和流动性的成形粉末。接着，采用高压压制和冷等静压两次成形，实现了较高的生坯密度并提高了生坯的均匀性。最后，通过两步烧结工艺抑制难熔金属粉末烧结后期的加速晶粒长大，在低温条件实现钨坯体的完全致密化，同时有效地控制了晶粒长大，最终制备出的纯钨制品具有高密度、晶粒小、热力学性能高的特点。
为实现本发明的目的，采用以下制备技术方案：一种金属材料的烧结致密化及晶粒尺寸控制方法，该方法的步骤如下：
首先对原料粉末进行解团聚处理，得到分散性好的解团聚粉末；
将解团聚粉末进行喷雾造粒以提高粉末流动性能和压坯密度均匀性，近球形造粒粉体；将得到近球形造粒粉体进行高压压制和冷等静压成形，得到压坯；将压坯经过两步无压烧结，即第一步烧结是将压坯快速升温，短时间保温，将致密度控制在75-85％、随后降温温度，再次进行长时间保温以进一步消除残余孔洞，即得到高致密度细晶粒金属。
进一步，所述方法的具体步骤为：
S1.以金属粉末为原料，采用高速螺旋叶片混合器对原料粉末进行解团聚处理，叶片的转速为2000-3000转/分钟，破碎时间为0.5-2小时，得到的解团聚粉末；
S2.首先将粘结剂和去离子水均匀混合制成溶液A，所述溶液A中的粘结剂含量为5-15wt.％；
然后在溶液A中加入步骤一得到解团聚原料粉末的并进行机械搅拌至混合均匀，制成浆料；采用离心式喷雾干燥机对所得的浆料进行喷雾造粒，转速范围为8000-15000r/min，雾化压力为100-300kPa，干燥温度在90-150℃；
将造粒粉末放入管式炉中通入高纯氢气进行脱脂和还原处理，处理温度为550-700℃、升温速率为5-10℃/min，保温时间为60-120min，得到近球形造粒粉体；
S3.将造粒粉体进行高压压制成形，压制压力为700-1000MPa，保压时间为0.5-1.5min，得到预成形坯体，预成形坯体装入包套模具中进行冷等静压，冷等静压压力为200-280MPa，保压时间为5-10min，得到成形坯；
S4、采用两步烧结：先第一步烧结是将S3制备得到的成形坯以一定的升温 速率加热至温度T 1，进行一步保温，得到一次烧结坯体；随后进行第二步烧结：将一次烧结坯体在T 1基础上以一定的速率降温至温度T 2，进行二步保温，即得到最终的超细晶金属，其中，T 2比T 1低50-250℃，一步保温时长小于二步次保温时长。
进一步，所述S1中所述金属粉末包括难熔金属；所述解团聚粉末的粒径小于0.5μm。
进一步，所述S2中粘结剂为聚乙烯醇、聚乙二醇、硬脂酸或石蜡；所述浆料中固相含量为60-85wt.％。
进一步，所述S3中成形坯的相对密度大于50％。
进一步，所述S4中的第一步烧结，成形坯体在氢气气氛中进行烧结，升温速率为5℃/min加热至T 1，T 1为1200-1500℃，保温时间为1-2h。
进一步，所述S4中的第二步烧结，保护气氛为采用氢气或者氩气气氛，由T 1降温至T 2，降温速率为15-25℃/min，保温时间10-60h。
进一步，所述一次烧结坯体的致密度为75-85％，晶粒尺寸为0.5-1μm，孔隙的大小和分布均匀。
进一步，所述得到超细晶金属晶粒尺寸/一次烧结坯晶粒尺寸≤1.5。
进一步，所述超细晶金属的致密度大于98％。
相比于第一步烧结后的一次烧结坯，第二步烧结过程中晶粒无明显长大。
与现有技术相比，本发明具有以下优点：
一、起始粉末的特性也会对两步烧结过程产生显著的影响，由于所用的粉末为纳米或亚微米级的粉末，颗粒越小越容易出现不规则团聚及在团聚体内部形成孔隙，利用高速旋转的叶片带动难熔金属粉末颗粒高速旋转，利用叶片的 剪切力及粉末颗粒之间的高速碰撞来使纳米粉末中的团聚体打开，所得粉末颗粒的粒度分布更窄，分散性更好。消除了纳米粉末的团聚体以及烧结过程中形成的晶粒内部的孔隙，这种孔隙即使通过后续的高温烧结也很难消除。同时，大幅度减小了晶粒的异常长大，提高了烧结坯中晶粒分布的均匀性。
二、造粒粉末相比于原始的不规则团聚体粉末，能够显著提高粉末在成形过程中粉末颗粒的流动性和填充模具的均匀性，有利于达到更高的粉末堆积密度，并使压坯不同部位的密度分布均匀。冷等静压技术也提高了成形坯体中密度分布的差异，有利于板坯在烧结过程均匀收缩，在一步烧结坯体中形成孔径大小均匀的孔隙结构，能够有效钉扎晶界的迁移，为第二步烧结过程中的进一步致密化奠定了基础。
三、两步烧结工艺能够有效抑制传统烧结工艺中烧结后期的晶粒加速长大，促进致密化且减小晶粒长大，制备的难熔金属在获得高的致密度的同时还能保持晶粒的细小，基本消除了异常长大的晶粒，并且具有高的显微组织均匀性，显著提高了难熔金属的力学性能。
四、两步烧结的过程中在不同烧结阶段采用不同的保护气氛，第一步烧结过程中的保护气氛为氢气，第二步烧结过程中的气氛为氩气。第一步烧结时采用氢气气氛具有还原净化的作用，能够去除成形坯中大部分的杂质氧，从而促进致密化进程。第二步烧结时采用氩气气氛，能够有效地去除氢气还原过程所产生的水蒸气，抑制了导致晶粒粗化的气相传输机制，从而起到抑制晶粒粗化的作用。
五、相比于普通烧结工艺，两步烧结工艺将烧结温度降低了300-500℃，降低了能耗和成本。该方法不限于钨、钼等难熔金属，还为其它高致密度细晶粒金属材料的制备提供了新的途径。
附图说明
图1为本发明一种金属材料的烧结致密化及晶粒尺寸控制方法的工艺流程图。
图2为本发明的工艺中的两步烧结工艺的示意图。第一步烧结是将生坯快速升温至一个较高的温度T 1，短时间保温以得到孔隙度为75-85％、且孔隙均匀的压坯，随后立即降温至较低温度T 2进行第二步烧结，较长时间保温以进一步消除残余孔洞而未发生晶粒长大。图中的NS表示普通烧结，TSS-Ⅰ表示两步烧结的第一步烧结，TSS-Ⅱ表示两步烧结的第二步烧结。其中，两步烧结的烧结温度T 1比普通烧结的烧结温度T 0低300-500℃，且两步烧结工艺在烧结后期晶粒无明显长大。
图3为粉末堆积状态对烧结的影响的示意图。Kingery和Francois在1967年最先认定粉末烧结过程中的孔洞存在一个临界的配位数Nc。假设一个孔洞被N个晶粒包围，N与粉末前期的堆积状态有关。那么，若某孔洞N<Nc(粉末堆积状态紧密)，孔洞与晶粒的界面凹向孔洞，孔洞收缩；若某孔洞N>Nc(粉末堆积状态松散)，该界面凸向孔洞，孔洞长大。特别地，存在有较大致密化驱动力的情况，使得N>Nc的大孔洞收缩，但必然伴随着相邻晶粒的异常长大。(a)为紧密的粉末堆积状态，烧结时孔洞容易收缩；(b)为疏松的粉末堆积状态，烧结时孔洞难以收缩，导致致密化驱动力更大，从而加剧致密化过程中的晶粒长大。因此减少N>Nc的大孔洞是控制烧结过程中晶粒长大的关键之一，提高生坯密度并改善粉末堆积状态是可行的方法。
图4为两步烧结过程中烧结坯体的孔隙结构变化示意图。孔洞通常在烧结后期难以收缩，在烧结后期的进一步致密化过程必然造成晶粒长大。传统烧结方式的晶粒长大速率往往和晶界迁移率有关。由Brook速度判据，孔洞与晶界之间 的运动的相对速度对晶粒长大速率有重要影响。第一种情况为晶界运动速度快于孔洞的运动速度时，会发生晶界与孔洞脱钩，即晶界脱离孔洞自由运动，则会造成孔洞滞留在晶粒内部难以收缩或是晶粒的异常长大；第二种情况为晶界上的孔洞运动速度低于晶界运动速度但不至于脱钩，孔洞的钉扎控制了晶粒的生长；第三种情况为晶界运动速度慢于孔洞运动速度，晶界的运动控制了晶粒长大。不同于第一种的晶界自由运动，第二种、第三种情况是慢的晶粒长大过程。两步烧结的机理在于，第一步在较高温度T 1下达到一定致密度，即刚形成闭合孔洞。第二步在较低温度T 2下，提供的烧结驱动力使得晶界运动速度慢于孔洞运动速率，且晶粒三节点或四节点的孔洞不动，从而实现慢速的晶粒长大。
图5为不同烧结工艺的纯钨的SEM显微组织。原始粉末为平均粒度为50nm的纯钨粉，(a)为普通烧结的状态(NS)，在1600℃氢气气氛下保温2h，晶粒尺寸约为3μm；(b)为两步烧结的第一步烧结状态(TSS-Ⅰ)，在1400℃氢气气氛下保温1h，晶粒尺寸约为0.5μm；(c)为两步烧结的第二步状态(TSS-Ⅱ)，在1400℃氢气气氛下保温1h后紧接着降温至1250℃在氩气气氛保温10h，晶粒尺寸约为0.7μm。
图6为不同烧结工艺的纯钼的SEM显微组织。原始粉末为平均粒度为30nm的纯钼粉，(a)为普通烧结的状态(NS)，在1500℃氢气气氛下保温2h，晶粒尺寸约为5μm；；(b)为两步烧结的第一步烧结状态(TSS-Ⅰ)，在1250℃氢气气氛下保温2h，晶粒尺寸约为1.5μm；(c)为两步烧结的第二步状态(TSS-Ⅱ)，在1250℃氢气气氛下保温1h紧接着降温至1150℃在氩气气氛保温40h，晶粒尺寸约为2μm。
具体实施方式
下面结合附图和具体实施例对本发明的技术方案做进一步说明。
本发明一种金属材料的烧结致密化及晶粒尺寸控制方法，该方法具体包括 以下步骤：
首先对原料粉末进行解团聚处理，得到分散性好的解团聚粉末；
将解团聚粉末进行喷雾造粒以提高粉末流动性能和压坯密度均匀性，近球形造粒粉体；将得到近球形造粒粉体进行高压压制和冷等静压成形，得到压坯；将压坯经过两步无压烧结，即第一步烧结是将压坯快速升温，短时间保温，将致密度控制在75-85％、随后降温温度，再次进行长时间保温以进一步消除残余孔洞，即得到高致密度细晶粒金属。
所述方法的具体步骤为：
S1.以金属粉末为原料，采用高速螺旋叶片混合器对原料粉末进行解团聚处理，叶片的转速为2000-3000转/分钟，破碎时间为0.5-2小时，得到的解团聚粉末；
S2.首先将粘结剂和去离子水均匀混合制成溶液A，所述溶液A中的粘结剂含量为5-15wt.％；
然后在溶液A中加入步骤一得到解团聚原料粉末的并进行机械搅拌至混合均匀，制成浆料；采用离心式喷雾干燥机对所得的浆料进行喷雾造粒，转速范围为8000-15000r/min，雾化压力为100-300kPa，干燥温度在90-150℃；
将造粒粉末放入管式炉中通入高纯氢气进行脱脂和还原处理，处理温度为550-700℃、升温速率为5-10℃/min，保温时间为60-120min，得到近球形造粒粉体；
S3.将造粒粉体进行高压压制成形，压制压力为700-1000MPa，保压时间为0.5-1.5min，得到预成形坯体，预成形坯体装入包套模具中进行冷等静压，冷等静压压力为200-280MPa，保压时间为5-10min，得到成形坯；
S4、采用两步烧结：先第一步烧结是将S3制备得到的成形坯以一定的升温速率加热至温度T 1，进行一步保温，得到一次烧结坯体；随后进行第二步烧结： 将一次烧结坯体在T 1基础上以一定的速率降温至温度T 2，进行二步保温，即得到最终的超细晶金属，其中，T 2比T 1低50-250℃，一步保温时长小于二步次保温时长(如图1所示)。
所述S1中所述金属粉末包括难熔金属；所述解团聚粉末的粒径小于0.5μm。
所述S2中粘结剂为聚乙烯醇、聚乙二醇、硬脂酸或石蜡；所述浆料中固相含量为60-85wt.％。
所述S3中成形坯的相对密度大于50％。
所述S4中的第一步烧结，成形坯体在氢气气氛中进行烧结，升温速率为5℃/min加热至T 1，T 1为1200-1500℃，保温时间为1-2h。
所述S4中的第二步烧结，保护气氛为采用氢气或者氩气气氛，由T 1降温至T 2，降温速率为15-25℃/min，保温时间10-60h。
所述一次烧结坯体的致密度为75-85％，晶粒尺寸为0.5-1μm，孔隙的大小和分布均匀。
所述得到超细晶金属晶粒尺寸/一次烧结坯晶粒尺寸≤1.5。
所述超细晶金属的致密度大于98％。
实施例1：
以50nm纯钨粉为原料，采用高速螺旋叶片混合器对原料粉末进行解团聚处理，叶片的转速为3000转/分钟，破碎时间为1小时，得到粒径分布更窄的解团聚原料粉末。将聚乙二醇和去离子水均匀混合制成溶液A，所述溶液A中的粘结剂含量为15wt.％，然后在溶液A中加入50nm原料钨粉并进行机械搅拌至混合均匀，制成浆料，所述浆料中固相含量为85wt.％；采用离心式喷雾干燥机对所得的浆料进行喷雾造粒，转速范围为15000r/min，雾化压力为300kPa，干燥温度在90℃；将造粒粉末放入管式炉中通入高纯氢气进行脱脂和还原处理，处理温 度为700℃、升温速率为5℃/min，保温时间为120min，得到近球形造粒粉体；对造粒粉体进行双向模压成形，压制压力为1000MPa，保压时间为1min，得到预成形坯体。预成形坯体装入包套模具中进行真空封装，然后进行冷等静压，冷等静压压制压强为280MPa，保压时间为5min，得到成形生坯；成形坯体在氢气气氛中进行第一步烧结，烧结温度为1400℃，升温速率为15℃/min，保温时间为1h。接着以20℃/min的速率快速降温至第二步烧结温度1250℃，此时将烧结气氛换为氩气，保温时间为10h，最终得到高致密且无晶粒长大的超细晶钨，显微组织如图5所示，致密度为98％，平均晶粒尺寸为0.7μm。
实施例2：
以50nm纯钨粉为原料，采用高速螺旋叶片混合器对原料粉末进行解团聚处理，叶片的转速为3000转/分钟，破碎时间为1小时，得到粒径分布更窄的解团聚原料粉末。将聚乙二醇和去离子水均匀混合制成溶液A，所述溶液A中的粘结剂含量为15wt.％，然后在溶液A中加入50nm原料钨粉并进行机械搅拌至混合均匀，制成浆料，所述浆料中固相含量为85wt.％；采用离心式喷雾干燥机对所得的浆料进行喷雾造粒，转速范围为15000r/min，雾化压力为300kPa，干燥温度在90℃；将造粒粉末放入管式炉中通入高纯氢气进行脱脂和还原处理，处理温度为700℃、升温速率为5℃/min，保温时间为120min，得到近球形造粒粉体；对造粒粉体进行双向模压成形，压制压力为1000MPa，保压时间为1min，得到预成形坯体。预成形坯体装入包套模具中进行真空封装，然后进行冷等静压，冷等静压压制压强为280MPa，保压时间为5min，得到成形生坯；成形坯体在氢气气氛中进行第一步烧结，烧结温度为1300℃，升温速率为15℃/min，保温时间为1h。接着以20℃/min的速率快速降温至第二步烧结温度1200℃，此时将烧结气氛换为氩气，保温时间为20h，最终得到高致密且无晶粒长大的超细晶钨，致 密度为97％，平均晶粒尺寸为0.6μm。
实施例3：
以200nm纯钨粉为原料，采用高速螺旋叶片混合器对原料粉末进行解团聚处理，叶片的转速为2500转/分钟，破碎时间为1小时，得到粒径分布更窄的解团聚原料粉末。将聚乙二醇和去离子水均匀混合制成溶液A，所述溶液A中的粘结剂含量为10wt.％，然后在溶液A中加入200nm原料钨粉并进行机械搅拌至混合均匀，制成浆料，所述浆料中固相含量为70wt.％；采用离心式喷雾干燥机对所得的浆料进行喷雾造粒，转速范围为12000r/min，雾化压力为200kPa，干燥温度在120℃；将造粒粉末放入管式炉中通入高纯氢气进行脱脂和还原处理，处理温度为600℃、升温速率为5℃/min，保温时间为120min，得到近球形造粒粉体；对造粒粉体进行双向模压成形，压制压力为900MPa，保压时间为1min，得到预成形坯体。预成形坯体装入包套模具中进行真空封装，然后进行冷等静压，冷等静压压制压强为250MPa，保压时间为5min，得到成形生坯；成形坯体在氢气气氛中进行第一步烧结，烧结温度为1400℃，升温速率为15℃/min，保温时间为1h。接着以20℃/min的速率快速降温至第二步烧结温度1250℃，此时将烧结气氛换为氩气，保温时间为20h，最终得到高致密且无晶粒长大的超细晶钨，致密度为97％，平均晶粒尺寸为1.5μm。
实施例4：
以400nm纯钨粉为原料，采用高速螺旋叶片混合器对原料粉末进行解团聚处理，叶片的转速为2000转/分钟，破碎时间为1小时，得到粒径分布更窄的解团聚原料粉末。将聚乙二醇和去离子水均匀混合制成溶液A，所述溶液A中的粘结剂含量为5wt.％，然后在溶液A中加入400nm原料钨粉并进行机械搅拌至混合均匀，制成浆料，所述浆料中固相含量为65wt.％；采用离心式喷雾干燥机对所得 的浆料进行喷雾造粒，转速范围为10000r/min，雾化压力为150kPa，干燥温度在140℃；将造粒粉末放入管式炉中通入高纯氢气进行脱脂和还原处理，处理温度为550℃、升温速率为5℃/min，保温时间为120min，得到近球形造粒粉体；对造粒粉体进行双向模压成形，压制压力为700MPa，保压时间为1min，得到预成形坯体。预成形坯体装入包套模具中进行真空封装，然后进行冷等静压，冷等静压压制压强为200MPa，保压时间为5min，得到成形生坯；成形坯体在氢气气氛中进行第一步烧结，烧结温度为1400℃，升温速率为15℃/min，保温时间为1h。接着以20℃/min的速率快速降温至第二步烧结温度1300℃，此时将烧结气氛换为氩气，保温时间为30h，最终得到高致密且无晶粒长大的超细晶钨，致密度为97％，平均晶粒尺寸为1.2μm。
实施例5：
以30nm纯钼粉为原料，采用高速螺旋叶片混合器对原料粉末进行解团聚处理，叶片的转速为2000转/分钟，破碎时间为1小时，得到粒径分布更窄的解团聚原料粉末。将聚乙二醇和去离子水均匀混合制成溶液A，所述溶液A中的粘结剂含量为5wt.％，然后在溶液A中加入30nm原料钼粉并进行机械搅拌至混合均匀，制成浆料，所述浆料中固相含量为60wt.％；采用离心式喷雾干燥机对所得的浆料进行喷雾造粒，转速范围为12000r/min，雾化压力为150kPa，干燥温度在140℃；将造粒粉末放入管式炉中通入高纯氢气进行脱脂和还原处理，处理温度为550℃、升温速率为5℃/min，保温时间为120min，得到近球形造粒粉体；对造粒粉体进行双向模压成形，压制压力为700MPa，保压时间为2min，得到预成形坯体。预成形坯体装入包套模具中进行真空封装，然后进行冷等静压，冷等静压压制压强为200MPa，保压时间为5min，得到成形生坯；成形坯体在氢气气氛中进行第一步烧结，烧结温度为1250℃，升温速率为15℃/min，保温时间为1h。 接着以20℃/min的速率快速降温至第二步烧结温度1150℃，此时将烧结气氛换为氩气，保温时间为40h，最终得到高致密且无晶粒长大的超细晶钼，显微组织如图6所示，致密度为97％，平均晶粒尺寸为2μm。
实施例6：
以30nm纯钼粉为原料，采用高速螺旋叶片混合器对原料粉末进行解团聚处理，叶片的转速为2000转/分钟，破碎时间为1小时，得到粒径分布更窄的解团聚原料粉末。将聚乙二醇和去离子水均匀混合制成溶液A，所述溶液A中的粘结剂含量为5wt.％，然后在溶液A中加入30nm原料钼粉并进行机械搅拌至混合均匀，制成浆料，所述浆料中固相含量为60wt.％；采用离心式喷雾干燥机对所得的浆料进行喷雾造粒，转速范围为12000r/min，雾化压力为150kPa，干燥温度在140℃；将造粒粉末放入管式炉中通入高纯氢气进行脱脂和还原处理，处理温度为550℃、升温速率为5℃/min，保温时间为120min，得到近球形造粒粉体；对造粒粉体进行双向模压成形，压制压力为700MPa，保压时间为2min，得到预成形坯体。预成形坯体装入包套模具中进行真空封装，然后进行冷等静压，冷等静压压制压强为200MPa，保压时间为5min，得到成形生坯；成形坯体在氢气气氛中进行第一步烧结，烧结温度为1350℃，升温速率为15℃/min，无保温时间。接着以20℃/min的速率快速降温至第二步烧结温度1200℃，此时将烧结气氛换为氩气，保温时间为40h，最终得到高致密且无晶粒长大的超细晶钼，致密度为98％，平均晶粒尺寸为1.2μm。
实施例7：
以50nm纯钼粉为原料，采用高速螺旋叶片混合器对原料粉末进行解团聚处理，叶片的转速为2000转/分钟，破碎时间为1小时，得到粒径分布更窄的解团聚原料粉末。将聚乙二醇和去离子水均匀混合制成溶液A，所述溶液A中的粘结 剂含量为5wt.％，然后在溶液A中加入50nm原料钼粉并进行机械搅拌至混合均匀，制成浆料，所述浆料中固相含量为60wt.％；采用离心式喷雾干燥机对所得的浆料进行喷雾造粒，转速范围为10000r/min，雾化压力为150kPa，干燥温度在140℃；将造粒粉末放入管式炉中通入高纯氢气进行脱脂和还原处理，处理温度为550℃、升温速率为5℃/min，保温时间为120min，得到近球形造粒粉体；对造粒粉体进行双向模压成形，压制压力为700MPa，保压时间为2min，得到预成形坯体。预成形坯体装入包套模具中进行真空封装，然后进行冷等静压，冷等静压压制压强为200MPa，保压时间为5min，得到成形生坯；成形坯体在氢气气氛中进行第一步烧结，烧结温度为1350℃，升温速率为15℃/min，无保温时间。接着以15℃/min的速率快速降温至第二步烧结温度1150℃，此时将烧结气氛换为氩气，保温时间为40h，最终得到高致密且无晶粒长大的超细晶钼，致密度为98％，平均晶粒尺寸为1.3μm。
实施例8：
以70nm纯钼粉为原料，采用高速螺旋叶片混合器对原料粉末进行解团聚处理，叶片的转速为2000转/分钟，破碎时间为1小时，得到粒径分布更窄的解团聚原料粉末。将聚乙二醇和去离子水均匀混合制成溶液A，所述溶液A中的粘结剂含量为5wt.％，然后在溶液A中加入70nm原料钼粉并进行机械搅拌至混合均匀，制成浆料，所述浆料中固相含量为60wt.％；采用离心式喷雾干燥机对所得的浆料进行喷雾造粒，转速范围为8000r/min，雾化压力为150kPa，干燥温度在140℃；将造粒粉末放入管式炉中通入高纯氢气进行脱脂和还原处理，处理温度为550℃、升温速率为5℃/min，保温时间为120min，得到近球形造粒粉体；对造粒粉体进行双向模压成形，压制压力为700MPa，保压时间为2min，得到预成形坯体。预成形坯体装入包套模具中进行真空封装，然后进行冷等静压，冷等静 压压制压强为200MPa，保压时间为5min，得到成形生坯；成形坯体在氢气气氛中进行第一步烧结，烧结温度为1250℃，升温速率为15℃/min，保温时间为2h。接着以25℃/min的速率快速降温至第二步烧结温度1200℃，此时将烧结气氛换为氩气，保温时间为40h，最终得到高致密且无晶粒长大的超细晶钼，致密度为97％，平均晶粒尺寸为1.8μm。
以上所述，仅为本发明的具体实施方式，但本发明的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本发明揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本发明的保护范围之内。因此，本发明的保护范围应以所述权利要求的保护范围为准。

Claims (10)

  1. 一种金属材料的烧结致密化及晶粒尺寸控制方法，其特征在于：该方法的步骤如下：
    首先对原料粉末进行解团聚处理，得到分散性好的解团聚粉末；将解团聚粉末进行喷雾造粒以提高粉末流动性能和压坯密度均匀性，近球形造粒粉体；将得到近球形造粒粉体进行高压压制和冷等静压成形，得到压坯；将压坯经过两步无压烧结，即第一步烧结是将压坯快速升温，短时间保温，将致密度控制在75-85％、随后降温温度，再次进行长时间保温以进一步消除残余孔洞，即得到高致密度细晶粒金属。
  2. 根据权利要求1所述的方法，其特征在于，所述方法的具体步骤为：
    S1.以金属粉末为原料，采用高速螺旋叶片混合器对原料粉末进行解团聚处理，叶片的转速为2000-3000转/分钟，破碎时间为0.5-2小时，得到的解团聚粉末；
    S2.首先将粘结剂和去离子水均匀混合制成溶液A，所述溶液A中的粘结剂含量为5-15wt.％；
    然后在溶液A中加入步骤一得到解团聚原料粉末的并进行机械搅拌至混合均匀，制成浆料；采用离心式喷雾干燥机对所得的浆料进行喷雾造粒，转速范围为8000-15000r/min，雾化压力为100-300kPa，干燥温度在90-150℃；
    将造粒粉末放入管式炉中通入高纯氢气进行脱脂和还原处理，处理温度为550-700℃、升温速率为5-10℃/min，保温时间为60-120min，得到近球形造粒粉体；
    S3.将造粒粉体进行高压压制成形，压制压力为700-1000MPa，保压时间为0.5-1.5min，得到预成形坯体，预成形坯体装入包套模具中进行冷等静压，冷等静压压力为200-280MPa，保压时间为5-10min，得到成形坯；
    S4、采用两步烧结：先第一步烧结是将S3制备得到的成形坯以一定的升温速率加热至温度T 1，进行一步保温，得到一次烧结坯体；随后进行第二步烧结：将一次烧结坯体在T 1基础上以一定的速率降温至温度T 2，进行二步保温，即得到最终的超细晶金属，其中，T 2比T 1低50-250℃，一步保温时长小于二步次保温时长。
  3. 根据权利要求2所述的方法，其特征在于：所述S1中所述金属粉末包括难熔金属；所述解团聚粉末的粒径小于0.5μm。
  4. 根据权利要求2所述的方法，其特征在于：所述S2中粘结剂为聚乙烯醇、聚乙二醇、硬脂酸或石蜡；所述浆料中固相含量为60-85wt.％。
  5. 根据权利要求2所述的方法，其特征在于：所述S3中成形坯的相对密度大于50％。
  6. 根据权利要求2所述的方法，其特征在于：所述S4中的第一步烧结，成形坯体在氢气气氛中进行烧结，升温速率为5℃/min加热至T 1，T 1为1200-1500℃，保温时间为1-2h。
  7. 根据权利要求2所述的方法，其特征在于：所述S4中的第二步烧结，保护气氛为采用氢气或者氩气气氛，由T 1降温至T 2，降温速率为15-25℃/min，保温时间10-60h。
  8. 根据权利要求2所述的方法，其特征在于：所述一次烧结坯体的致密度为75-85％，晶粒尺寸为0.5-1μm，孔隙的大小和分布均匀。
  9. 根据权利要求2所述的方法，其特征在于：所述得到超细晶金属晶粒尺寸/一次烧结坯晶粒尺寸≤1.5。
  10. 根据权利要求2所述的方法，其特征在于：所述超细晶金属的致密度大于98％。
PCT/CN2018/123568 2018-12-24 2018-12-25 一种金属材料的烧结致密化及晶粒尺寸控制方法 WO2020132881A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US16/793,897 US11673196B2 (en) 2018-12-24 2020-02-18 Metal material sintering densification and grain size control method

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201811583483.7A CN109676124B (zh) 2018-12-24 2018-12-24 一种金属材料的烧结致密化及晶粒尺寸控制方法
CN201811583483.7 2018-12-24

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US16/793,897 Continuation US11673196B2 (en) 2018-12-24 2020-02-18 Metal material sintering densification and grain size control method

Publications (1)

Publication Number Publication Date
WO2020132881A1 true WO2020132881A1 (zh) 2020-07-02

Family

ID=66189019

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2018/123568 WO2020132881A1 (zh) 2018-12-24 2018-12-25 一种金属材料的烧结致密化及晶粒尺寸控制方法

Country Status (2)

Country Link
CN (1) CN109676124B (zh)
WO (1) WO2020132881A1 (zh)

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111825432A (zh) * 2020-07-31 2020-10-27 中南大学湘雅医院 一种细晶粒粉色zta陶瓷及其制备方法
CN111960465A (zh) * 2020-08-13 2020-11-20 厦门厦瑞博科技有限公司 一种球型ZrO2粉末的制备方法
CN111992722A (zh) * 2020-08-18 2020-11-27 苏州卓米智能制造科技有限公司 一种复杂mim零件加工方法
CN112723862A (zh) * 2020-12-29 2021-04-30 太原理工大学 简单低耗制备高熵氧化物陶瓷材料的方法
CN112962069A (zh) * 2021-02-02 2021-06-15 长沙淮石新材料科技有限公司 一种含金属间化合物的铝合金靶材及其制备方法
CN113281135A (zh) * 2021-05-31 2021-08-20 钢研纳克检测技术股份有限公司 一种金属微观力学性能高通量跨尺度统计表征方法
CN113292324A (zh) * 2021-06-18 2021-08-24 中国船舶重工集团公司第七二五研究所 一种不需要筛分的实心球形at13喷涂喂料的制备方法
CN113652594A (zh) * 2021-08-02 2021-11-16 自贡硬质合金有限责任公司 一种难熔金属基合金及其制备方法
CN113664197A (zh) * 2021-08-13 2021-11-19 郑州航空工业管理学院 一种高强塑性粉末高温合金及其制备方法和应用
CN114147213A (zh) * 2021-11-19 2022-03-08 江苏精研科技股份有限公司 基于高氮无镍不锈钢用于粉末注射成形的制备方法
CN114713833A (zh) * 2022-03-10 2022-07-08 崇义章源钨业股份有限公司 基于原位还原的球形钨基复合粉末及其制备方法
CN114799184A (zh) * 2022-05-12 2022-07-29 江西咏泰粉末冶金有限公司 一种高均匀大颗粒球形复合粉末的制备方法
CN115194156A (zh) * 2022-07-29 2022-10-18 鄂信钻石新材料股份有限公司 一种改良型金刚石合金刀头及其制备工艺
CN115213415A (zh) * 2022-07-22 2022-10-21 中国兵器工业第五九研究所 一种高性能复合材料药型罩的制备方法
CN115233022A (zh) * 2022-09-23 2022-10-25 西安稀有金属材料研究院有限公司 一种超高硬度纳米结构钼铝合金及其制备方法
CN118162615A (zh) * 2024-05-16 2024-06-11 西安格美金属材料有限公司 一种大规格钨芯杆制备方法
CN118437927A (zh) * 2024-07-08 2024-08-06 安徽朗盛环能科技有限公司 一种基于合金材料镀覆工艺的金属滤芯制备方法

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110983264B (zh) * 2019-12-23 2022-11-15 有研亿金新材料(山东)有限公司 一种高密度细晶粒易成型的w靶材的制备方法
CN112828298B (zh) * 2020-12-31 2022-10-04 中国人民解放军空军工程大学 高温钼合金球形粉体制备方法
CN114464443B (zh) * 2022-01-17 2024-02-06 北京工业大学 一种同时提高多主相LaCe基烧结永磁材料矫顽力和耐腐蚀性的方法
CN114619038B (zh) * 2022-01-31 2023-04-25 北京科技大学 一种高纯度的钨钛合金靶材的制备方法
CN114959341B (zh) * 2022-05-20 2024-06-04 北京科技大学 一种制备高强高塑难熔合金的方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05148568A (ja) * 1991-11-25 1993-06-15 Nkk Corp 高密度粉末焼結用チタン合金
CN101805867A (zh) * 2009-12-01 2010-08-18 中南大学 Si3N4基金属陶瓷及其制备方法
CN105518169A (zh) * 2014-10-20 2016-04-20 中南大学 一种稀土氧化物弥散强化细晶钨材料的制备方法
CN108330371A (zh) * 2018-03-02 2018-07-27 北京科技大学 一种纳米相分离烧结制备钨材料的方法
CN108907211A (zh) * 2018-08-16 2018-11-30 北京科技大学 一种制备大尺寸钼板坯的方法
CN109047780A (zh) * 2018-08-16 2018-12-21 北京科技大学 一种制备高致密度钨烧结制品的方法

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4179973B2 (ja) * 2003-11-18 2008-11-12 Ｔｄｋ株式会社 焼結磁石の製造方法
CN105478776B (zh) * 2015-12-14 2019-09-10 北京科技大学 一种低温烧结制备高致密度纯钨制品的方法
CN106312057B (zh) * 2016-09-13 2020-11-17 上海交通大学 纳米颗粒增强超细晶金属基复合材料的粉末冶金制备方法
CN109047781B (zh) * 2018-08-16 2021-11-30 北京科技大学 一种制备大尺寸钨制品的方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05148568A (ja) * 1991-11-25 1993-06-15 Nkk Corp 高密度粉末焼結用チタン合金
CN101805867A (zh) * 2009-12-01 2010-08-18 中南大学 Si3N4基金属陶瓷及其制备方法
CN105518169A (zh) * 2014-10-20 2016-04-20 中南大学 一种稀土氧化物弥散强化细晶钨材料的制备方法
CN108330371A (zh) * 2018-03-02 2018-07-27 北京科技大学 一种纳米相分离烧结制备钨材料的方法
CN108907211A (zh) * 2018-08-16 2018-11-30 北京科技大学 一种制备大尺寸钼板坯的方法
CN109047780A (zh) * 2018-08-16 2018-12-21 北京科技大学 一种制备高致密度钨烧结制品的方法

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111825432A (zh) * 2020-07-31 2020-10-27 中南大学湘雅医院 一种细晶粒粉色zta陶瓷及其制备方法
CN111960465A (zh) * 2020-08-13 2020-11-20 厦门厦瑞博科技有限公司 一种球型ZrO2粉末的制备方法
CN111992722A (zh) * 2020-08-18 2020-11-27 苏州卓米智能制造科技有限公司 一种复杂mim零件加工方法
CN112723862A (zh) * 2020-12-29 2021-04-30 太原理工大学 简单低耗制备高熵氧化物陶瓷材料的方法
CN112962069A (zh) * 2021-02-02 2021-06-15 长沙淮石新材料科技有限公司 一种含金属间化合物的铝合金靶材及其制备方法
CN113281135A (zh) * 2021-05-31 2021-08-20 钢研纳克检测技术股份有限公司 一种金属微观力学性能高通量跨尺度统计表征方法
CN113281135B (zh) * 2021-05-31 2023-08-15 钢研纳克检测技术股份有限公司 一种金属微观力学性能高通量跨尺度统计表征方法
CN113292324B (zh) * 2021-06-18 2022-11-18 中国船舶重工集团公司第七二五研究所 一种不需要筛分的实心球形at13喷涂喂料的制备方法
CN113292324A (zh) * 2021-06-18 2021-08-24 中国船舶重工集团公司第七二五研究所 一种不需要筛分的实心球形at13喷涂喂料的制备方法
CN113652594A (zh) * 2021-08-02 2021-11-16 自贡硬质合金有限责任公司 一种难熔金属基合金及其制备方法
CN113664197A (zh) * 2021-08-13 2021-11-19 郑州航空工业管理学院 一种高强塑性粉末高温合金及其制备方法和应用
CN114147213A (zh) * 2021-11-19 2022-03-08 江苏精研科技股份有限公司 基于高氮无镍不锈钢用于粉末注射成形的制备方法
CN114713833A (zh) * 2022-03-10 2022-07-08 崇义章源钨业股份有限公司 基于原位还原的球形钨基复合粉末及其制备方法
CN114713833B (zh) * 2022-03-10 2024-03-22 崇义章源钨业股份有限公司 基于原位还原的球形钨基复合粉末及其制备方法
CN114799184A (zh) * 2022-05-12 2022-07-29 江西咏泰粉末冶金有限公司 一种高均匀大颗粒球形复合粉末的制备方法
CN115213415A (zh) * 2022-07-22 2022-10-21 中国兵器工业第五九研究所 一种高性能复合材料药型罩的制备方法
CN115213415B (zh) * 2022-07-22 2024-03-29 中国兵器工业第五九研究所 一种高性能复合材料药型罩及其制备方法
CN115194156A (zh) * 2022-07-29 2022-10-18 鄂信钻石新材料股份有限公司 一种改良型金刚石合金刀头及其制备工艺
CN115233022A (zh) * 2022-09-23 2022-10-25 西安稀有金属材料研究院有限公司 一种超高硬度纳米结构钼铝合金及其制备方法
CN118162615A (zh) * 2024-05-16 2024-06-11 西安格美金属材料有限公司 一种大规格钨芯杆制备方法
CN118437927A (zh) * 2024-07-08 2024-08-06 安徽朗盛环能科技有限公司 一种基于合金材料镀覆工艺的金属滤芯制备方法

Also Published As

Publication number Publication date
CN109676124A (zh) 2019-04-26
CN109676124B (zh) 2020-02-28

Similar Documents

Publication Publication Date Title
WO2020132881A1 (zh) 一种金属材料的烧结致密化及晶粒尺寸控制方法
US11673196B2 (en) Metal material sintering densification and grain size control method
CN110560700B (zh) 一种制备高致密度超细晶稀土氧化物掺杂钨合金的方法
CN109047781B (zh) 一种制备大尺寸钨制品的方法
CN110512107B (zh) 一种微量元素和稀土氧化物复合强化钨基复合材料的制备方法
CN108907211B (zh) 一种制备大尺寸钼板坯的方法
CN112222419B (zh) 一种调控形核和生长过程制备纳米钼粉的方法及应用
CN112030026B (zh) 一种高硬度、高致密度复合稀土氧化物掺杂钨基复合材料的制备方法
CN109234557B (zh) 一种超细高硬度w-y2o3复合材料的制备方法
CN112222421B (zh) 一种纳米三氧化钨和纳米钨粉的制备方法及应用
CN109047780A (zh) 一种制备高致密度钨烧结制品的方法
CN112222418B (zh) 一种调控形核和生长过程制备纳米钨粉的方法及应用
CN112226662B (zh) 一种高温稳定性好的双纳米结构钨合金及其制备方法与应用
CN106513683A (zh) 制备细晶高致密的氧化钇弥散强化钨基合金的方法
CN113106281A (zh) 一种氧化钇掺杂钨基纳米复合粉体及其合金的制备方法
CN115353373A (zh) 一种氧化铝靶材及其制备方法与应用
CN113943159A (zh) 一种碳化硼复合陶瓷的制备方法
CN109940158B (zh) 一种细晶钼板的快速制备工艺
CN112658273B (zh) 一种第二相颗粒弥散钼复合粉末的冷冻干燥制备方法
KR20120072235A (ko) 페라이트계 산화물 분산강화합금 및 그 제조방법
CN103602868A (zh) 一种高密度细晶粒W-TiC合金材料的制备方法
CN112222420B (zh) 一种掺杂金属氧化物纳米颗粒的纳米钨粉及其制备方法
CN114309609A (zh) 一种钨钛合金靶材的制备方法
CN108447576B (zh) 一种max相改进型二氧化铀芯块的制备方法
CN113441728A (zh) 一种高均匀超细/纳米钨粉的制备方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 18944161

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 18944161

Country of ref document: EP

Kind code of ref document: A1