Alloy solid solution, preparation method, hard alloy and application

Abstract

The invention relates to the technical field of hard alloy materials, in particular to an alloy solid solution, a preparation method, hard alloy and application. The alloy solid solution is prepared from the following raw materials in parts by weight: 15 to 17 parts of tantalum oxide, 15 to 30 parts of titanium carbonitride, 45 to 60 parts of tungsten carbide, 1 to 4 parts of carbon black, 5 to 10 parts of cobalt, 0.1 to 0.7 part of chromium nitride, 0.01 to 0.1 part of trace metal and 0.001 to 0.003 part of rare earth; the trace metal comprises at least one of indium, tin and copper sources. The alloy solid solution provided by the invention is prepared from tantalum oxide, titanium carbonitride, tungsten carbide, carbon black, cobalt and chromium nitride, and has the advantages of high purity, good toughness, high hardness, wear resistance, high temperature resistance and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hard alloy materials, in particular to an alloy solid solution and a preparation method thereof, a hard alloy and application. BACKGROUND

[0002] Tungsten-titanium-tantalum-cobalt hard alloy (WC+TiC+TaC+Co) is a kind of material with high hardness, wear resistance and high temperature resistance, which is composed of tungsten carbide powder, titanium carbide (TiC) powder, tantalum carbide (TaC) powder and cobalt (Co) powder, so it is also called general hard alloy or universal (YW type) hard alloy.

[0003] The preparation of tungsten-titanium-tantalum-cobalt hard alloy is an alloy material added with a proper amount of TAC powder on the basis of tungsten-titanium-cobalt hard alloy. The commonly used method is to mix various materials in proportion for a long time of ball milling, but this method is difficult to completely uniform and long time of ball milling also brings the mixing of other impurities, thereby affecting the performance of the alloy; in addition, the existing hard alloy still cannot meet the demand in hot hardness, and cannot take into account the double effect of hot hardness and impact work. SUMMARY

[0004] To solve the above problems, the present application provides an alloy solid solution and a preparation method thereof, a hard alloy and application. To solve at least one aspect of the above technical problems.

[0005] The present application is realized by the following technical schemes: In a first aspect, the present application provides an alloy solid solution, which comprises the following raw materials in parts by weight: 15-17 parts of tantalum oxide, 15-30 parts of titanium carbonitride, 45-60 parts of tungsten carbide, 1-4 parts of carbon black, 5-10 parts of cobalt, 0.1-0.7 parts of chromium nitride, 0.01-0.1 parts of trace metals, and 0.001-0.003 parts of rare earths; The trace metals include at least one of indium, tin and copper sources.

[0006] In a second aspect, the present application provides a preparation method of an alloy solid solution, which comprises the following steps: S10. The green compact is subjected to solid solution treatment to obtain an alloy solid solution powder; The raw materials of the green compact include tantalum oxide, titanium carbonitride, tungsten carbide, carbon black, cobalt, chromium nitride, trace metals and rare earths.

[0007] In a third aspect, the present application provides a hard alloy, which comprises the above-mentioned alloy solid solution.

[0008] In a fourth aspect, the present application provides a use of the hard alloy in the field of cutters.

[0009] The alloy solid solution and the preparation method thereof, and the hard alloy and the preparation method thereof have at least the following beneficial technical effects compared with the prior art. (1) The alloy solid solution is made of tantalum oxide, titanium carbonitride, tungsten carbide, carbon black, cobalt and chromium nitride, and has the advantages of high purity, good toughness, high hardness, wear resistance and high temperature resistance.

[0010] (2) The preparation method of the alloy solid solution is to make the raw materials into a green body to realize mechanical alloying of the raw materials, so that Ta2O5 nanoparticles are firmly embedded on the surfaces of TiCN and WC particles, and convenience is provided for subsequent reactions.

[0011] (3) The preparation method of the alloy solid solution is simple and easy to implement.

[0012] (4) The hard alloy provided by the application has improved thermal shock resistance and thermal hardness due to the use of the alloy solid solution. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the drawings, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the drawings shown.

[0014] Figure 1 The XRD pattern of the alloy solid solution provided in Embodiment 1 of the present application; Figure 2 The SEM pattern of the alloy solid solution provided in Embodiment 1 of the present application; Figure 3 The SEM pattern of the alloy solid solution provided in Embodiment 2 of the present application.

[0015] The realization, functional features and advantages of the present application will be further described with reference to the drawings. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be described and explained in the following embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application. Based on the embodiments provided by the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0017] Obviously, the following description is merely some examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, modifications to design, manufacturing, or production based on the technical content disclosed in this invention are merely conventional technical means and should not be construed as insufficient disclosure of the present invention.

[0018] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand the invention and is not intended to limit the subject matter of the claims.

[0019] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions, and all technical features and optional technical features of the present invention can be combined with each other to form new technical solutions.

[0020] The first aspect of this invention provides an alloy solid solution comprising the following raw materials in parts by weight: 15-17 parts tantalum oxide, 15-30 parts titanium carbonitride, 45-60 parts tungsten carbide, 1-4 parts carbon black, 5-10 parts cobalt, 0.1-0.7 parts chromium nitride, 0.01-0.1 parts trace metals, 0.001-0.003 parts rare earth elements; The trace metal includes at least one of indium, tin, and copper.

[0021] The alloy solid solution provided in this embodiment of the invention is an alloy solid solution made of tantalum oxide, titanium carbonitride, tungsten carbide, carbon black, cobalt, chromium nitride, trace metals and rare earth elements. It has the advantages of high purity, good toughness, high hardness, wear resistance and high temperature resistance.

[0022] In this embodiment, the weight percentage of tantalum oxide is 15 to 17 parts. In this case, tantalum oxide serves as the core tantalum source, reacting with carbon black in situ to generate TaC. x .

[0023] In the examples, the titanium carbonitride was present in parts by weight of 15 to 30. In this case, the ratio of C to N in the titanium carbonitride could be coordinated with the in-situ reduction product of tantalum oxide to prepare a single-phase alloy solid solution.

[0024] In the examples, the tungsten carbide comprises 45 to 60 parts by weight. In this case, WC provides W atoms to participate in the solid solution formation of a single-phase alloy solid solution.

[0025] In the examples, the carbon black is present in parts by weight of 1 to 4 parts. In this case, the carbon black can reduce Ta₂O₅ to TaC. x .

[0026] In the embodiments, the cobalt content is 5 to 10 parts by weight. In this case, Co acts as a binder phase, which can both fill the pores to ensure hardness and provide sufficient toughness for bridging.

[0027] In the examples, the chromium nitride content is 0.1 to 0.7 parts by weight. In this case, CrN can purify grain boundaries, improve wettability, and simultaneously provide Cr to enhance red hardness.

[0028] In this embodiment, the trace metals are present in parts by weight of 0.01 to 0.1. In this case, indium and tin have low melting points, which can significantly reduce the temperature required for melting and improve the hardness and toughness of the solid solution; copper source has a low melting point, which can reduce the temperature required for melting and improve the hardness and wear resistance of the solid solution.

[0029] In some embodiments, the mass fraction of impurities in tantalum oxide is less than 0.034%.

[0030] In some specific embodiments, the impurities and their mass fractions in tantalum oxide include: Fe<0.01%, Ca<0.005%, Al<0.005%, Si<0.01%, Na<0.004%.

[0031] In some embodiments, titanium carbonitride includes TiC 0.7 N 0.3 .

[0032] In some embodiments, TiC 0.7 N 0.3 The preparation includes the following steps: According to TiC 0.7 N 0.3 The molar ratio is used to obtain the mass of the titanium source, carbon source, and nitrogen source; The titanium source, carbon source and nitrogen source were mixed, ball-milled and then annealed.

[0033] The above TiC 0.7 N 0.3 In the preparation process, ball milling enables the titanium, carbon, and nitrogen sources to be mixed at the elemental level and react, resulting in a powder product with extremely fine grains; annealing can eliminate the large internal stress in the ball-milled product and stabilize TiC. 0.7 N 0.3 Crystal form of the product.

[0034] In some embodiments, the titanium source includes titanium powder.

[0035] In some embodiments, the carbon source includes at least one of graphite powder and urea (CH4N2O).

[0036] In some embodiments, the nitrogen source includes urea (CH4N2O). In this case, the urea is decomposed during ball milling to provide active nitrogen atoms.

[0037] In some embodiments, the ball-to-material (mass) ratio in the ball mill is (10~20):1.

[0038] In some embodiments, a star ball mill is used to mix and ball mill the titanium source, carbon source, and nitrogen source.

[0039] In some embodiments, annealing includes the following steps: Annealing is performed under vacuum or nitrogen protection.

[0040] In some embodiments, the annealing temperature is 800°C to 1000°C.

[0041] In some embodiments, the annealing time is 1 hour to 2 hours.

[0042] In some embodiments, the impurity content in tungsten carbide is less than 0.034%.

[0043] In some specific embodiments, the impurities and their mass fractions in the tungsten carbide include: Fe<0.01%, Ca<0.005%, Al<0.005%, Si<0.01%, Na<0.004%.

[0044] In some embodiments, the ash content of carbon black is 0.01% to 0.1%.

[0045] In some embodiments, the purity of the carbon black is 99.97% or higher.

[0046] In some embodiments, the purity of cobalt is 99.95% or higher.

[0047] In some embodiments, the purity of chromium nitride is 99.95% or higher.

[0048] In some embodiments, the D of chromium nitride 50 The range is 0.8μm to 1.2μm.

[0049] In some embodiments, the copper source includes a copper alloy.

[0050] In some embodiments, the copper alloy comprises the following components by mass fraction: Sn 10%, Zn 2%, balance is copper and unavoidable impurities.

[0051] The aforementioned copper alloy contains small amounts of tin and zinc. When the alloy is made into a solid solution, an oxide film can be formed on the surface, which improves the corrosion resistance of the solid solution; copper improves the wear resistance of the solid solution.

[0052] In some embodiments, rare earth elements include at least one of neodymium, lanthanum, and cerium.

[0053] In some embodiments, the Fisher grain size of the alloy solid solution is less than 2.0 μm.

[0054] In some embodiments, the Fisher grain size of the alloy solid solution is less than 1.5 μm.

[0055] A second aspect of this invention provides a method for preparing the above-mentioned alloy solid solution, comprising the following steps: S10. The compact is subjected to solution treatment to obtain alloy solid solution powder; The raw materials for the pressed compact include tantalum oxide, titanium carbonitride, tungsten carbide, carbon black, cobalt, chromium nitride, trace metals, and rare earth elements.

[0056] The method for preparing an alloy solid solution provided in this embodiment of the invention involves performing a solid solution treatment on a pressed billet, and the resulting alloy solid solution is a single phase.

[0057] In some embodiments, the preparation of the pressed blank in step S10 above includes the following steps: S101. The mixture of materials and binder is mixed and then pressed bidirectionally.

[0058] In some embodiments, the preparation of the mixture in step S101 above includes the following steps: S1011. The raw materials of the mixture are ball-milled and mixed.

[0059] In the preparation of the above mixture, ball milling the raw materials can achieve mechanical alloying of the raw materials, so that tantalum oxide nanoparticles are firmly embedded on the surface of TiCN and WC particles, which facilitates subsequent sintering.

[0060] In some embodiments, the ball milling mixing step in step S1011 above includes: S10111. After the first ball milling of tantalum oxide, titanium carbonitride, tungsten carbide and carbon black, cobalt, chromium nitride, trace metals and rare earth elements are added for the second ball milling.

[0061] In the above-described ball milling mixing steps, a first ball milling is performed to firmly embed tantalum oxide nanoparticles onto the surface of TiCN and WC particles; a second ball milling is then performed to improve the toughness, bridging, and uniformity of the mixture. The grinding balls, ball-to-material ratio, and milling time for both the first and second ball milling processes are within the aforementioned ranges.

[0062] In some embodiments, in step S10111 above, the ball-to-material ratio of the first ball mill is 100:(160~180).

[0063] In some embodiments, in step S10111 above, the grinding balls selected in the first ball mill are tungsten carbide balls.

[0064] In some embodiments, in step S10111 above, in the first ball milling, medium-diameter grinding balls and small-diameter grinding balls are mixed and ground in a ratio of 1:(20~30).

[0065] In some embodiments, the diameter of the medium-diameter grinding ball is 15mm to 20mm.

[0066] In some embodiments, the diameter of the small-diameter grinding ball is 7mm to 10mm.

[0067] In some embodiments, in step S10111 above, the first ball milling time is 6 to 7 hours. In this case, ball milling can sufficiently refine the grains, maintain the crystal structure, and reduce the introduction of impurities.

[0068] In some embodiments, in step S10111 above, the ball-to-material ratio of the second ball mill is 100:(160~180).

[0069] In some embodiments, in step S10111 above, the grinding balls selected in the second ball mill are tungsten carbide balls.

[0070] In some embodiments, in step S10111 above, in the second ball milling, medium-diameter grinding balls and small-diameter grinding balls are mixed and ground in a ratio of 1:(20~30).

[0071] In some embodiments, the diameter of the medium-diameter grinding ball is 15mm to 20mm.

[0072] In some embodiments, the diameter of the small-diameter grinding ball is 7mm to 10mm.

[0073] In some embodiments, in step S10111 above, the second ball milling time is 6 to 7 hours. In this case, ball milling can sufficiently refine the grains, maintain the crystal structure, and reduce the introduction of impurities.

[0074] In some embodiments, in step S1011 above, the ball milling uses a QM-WX horizontal ball mill.

[0075] In some embodiments, the mixing rate in the ball mill is 80 kg / furnace to 300 kg / furnace.

[0076] In some embodiments, in step S101 described above, the adhesive includes a polypropylene-based adhesive.

[0077] In some embodiments, the polypropylene-based binder is a mixture of ethylene-vinyl acetate copolymer, polypropylene, paraffin wax, and stearic acid.

[0078] In some embodiments, the polypropylene-based adhesive comprises the following components by mass fraction: 10%~20% ethylene-vinyl acetate copolymer, 62%~75% polypropylene, 10%~15% paraffin wax and 1%~3% stearic acid.

[0079] In some embodiments, the mass fraction of vinyl acetate (VA) in the ethylene-vinyl acetate copolymer is 25% to 40%.

[0080] In some embodiments, the CAS number for polypropylene is 9003-07-0.

[0081] In some embodiments, in step S101 above, the amount of adhesive used is 1% to 1.5% of the mass of the mixture.

[0082] In some embodiments, in step S101 above, the pressure of bidirectional compression is 200MPa~210MPa.

[0083] In some embodiments, the preparation of the pressed blank in step S10 above further includes the following steps: S102. Degrease the compact obtained by biaxial pressing.

[0084] In some embodiments, in step S102 above, the degreasing atmosphere is nitric acid vapor.

[0085] In some embodiments, the degreasing temperature in step S102 is 120°C to 130°C. It should be noted that the endpoint of degreasing is conventional in the art and is not particularly limited in the embodiments of the present invention.

[0086] In some specific embodiments, in step S102 above, degreasing includes the following steps: S1021. In a continuous catalytic degreasing furnace, under nitrogen protection, the pressed blank is degreased.

[0087] In some embodiments, in step S10 above, the solution treatment includes: S103. The pressed billet is subjected to the following steps: first heating and holding, supercritical fluid quenching, second heating and holding, and gas quenching.

[0088] In the above solution treatment, the first heating and holding can reduce Ta2O5 to TaC. x Finally, it forms a (Ta,Ti,W)(C,N) solid solution phase with titanium carbonitride and tungsten carbide. Supercritical fluid quenching rapidly cools the high-temperature sintered billet, refining the grains while maintaining the (Ta,Ti,W)(C,N) solid solution phase, and causing the (Ta,Ti,W)(C,N) solid solution phase to form a eutectic structure with ultrafine WC. The second heating and holding promotes the uniform melting of the (Ta,Ti,W)(C,N) solid solution phase, ultrafine WC, cobalt, chromium nitride, trace metals, and rare earth elements, forming a homogeneous alloy solid solution. Gas quenching allows the sintered billet to cool rapidly, preventing the precipitation of grains from the generated alloy solid solution, which would reduce the product's hardness and other mechanical properties. The solution treatment causes the elements in the billet to form a single-phase tungsten carbonitride-titanium-tantalum solid solution.

[0089] In some embodiments, in step S103 above, the first heating and heat preservation step includes: S1031. Under an inert protective atmosphere, the pressed blank is heated to 2000℃~2100℃ at a heating rate of 20℃ / min~30℃ / min and then held at that temperature.

[0090] In this case, the compact carbonizes as the temperature rises, and Ta2O5 is reduced to TaC. x After heating to the holding temperature, the mixture is held at that temperature to form a (Ta,Ti,W)(C,N) solid solution phase.

[0091] In some embodiments, in step S1031 above, the pressure of the inert protective atmosphere is 47 kPa to 50 kPa. Under this pressure, the escape rate of CO gas generated in the carbothermic reduction reaction of Ta2O5 can be suppressed, thereby creating a "microenvironment" with locally high CO partial pressure between particles, allowing the compact to undergo heat-holding carbonization at a lower temperature. Furthermore, the escaped CO acts as a self-protective gas for the carbonization system, isolating the alloy system from the influence of external air infiltration and preventing N from reacting with oxygen to generate nitrogen oxides.

[0092] In some embodiments, in step S1031 above, the inert protective atmosphere includes argon or helium.

[0093] In some embodiments, the holding time in step S1031 is 60 min to 120 min. In this case, the short holding time allows the formed TaC (tantalum carbide) to simultaneously undergo solid solution reaction with titanium carbonitride and tungsten carbide (the solid solution reaction equation is: WC + TiCN + TaC = (Ta,Ti,W)(C,N)) to obtain the (Ta,Ti,W)(C,N) solid solution phase.

[0094] In some embodiments, in step S103 above, the supercritical fluid in supercritical fluid quenching includes supercritical carbon dioxide.

[0095] In some embodiments, the supercritical fluid quenching step in step S103 above includes: S1032. The sintered billet obtained by the first heating and holding is placed in a supercritical fluid to cool down to 800℃~900℃, then heated to 1000℃~1200℃ and held, and then cooled down again to below 100℃ using a supercritical fluid.

[0096] In the above-mentioned supercritical fluid quenching process, the sintered billet obtained by the first heating and holding is rapidly cooled to 800℃~900℃ using supercritical fluid, which can stabilize the (Ta,Ti,W)(C,N) solid solution phase while refining the grains; then, it is heated to 1000℃~1200℃ and held, which can allow the (Ta,Ti,W)(C,N) solid solution phase to form a eutectic structure with ultrafine WC; then, the pressed billet is rapidly cooled to below 100℃ using supercritical fluid, in order to stabilize the (Ta,Ti,W)(C,N) solid solution phase and the eutectic structure formed by the (Ta,Ti,W)(C,N) solid solution phase and ultrafine WC.

[0097] In some embodiments, in step S1032 above, the time for holding the temperature at 1000℃~1200℃ is 0.5h~1h.

[0098] In some embodiments, in step S103 above, the second heating and heat preservation step includes: S1033. Under an inert protective atmosphere, the pressed blank is heated to 1350℃~1400℃ at a heating rate of 10℃ / min~20℃ / min and then held at that temperature.

[0099] In the second heating and holding process mentioned above, the compact is heated slowly to 1350℃~1400℃ and held for a period of time to promote the uniform melting of the (Ta,Ti,W)(C,N) solid solution phase, ultrafine WC, cobalt, chromium nitride, trace metals and rare earth elements, forming a uniform alloy solid solution.

[0100] In some embodiments, in step S1033 above, the pressure of the inert protective atmosphere is atmospheric pressure (101 kPa ± 0.325 kPa).

[0101] In some embodiments, in step S1033 above, the heat preservation time is 30 min to 60 min.

[0102] In some embodiments, in step S103 above, the gas quenching pressure is 1000 kPa ± 10 kPa.

[0103] In some embodiments, in step S103 above, the gas used in gas quenching includes at least one of argon and helium.

[0104] In some embodiments, the solution treatment in step S10 above further includes the following steps: S104. Vacuum clean the pressed blank to remove impurities.

[0105] In the above solution treatment, the compact is first vacuum-removed for impurities, and then subjected to subsequent first heating and heat preservation treatments to remove gaseous impurities that escape from the compact at high temperatures.

[0106] In some embodiments, in step S104 above, vacuum purification includes the following steps: S1041. Under vacuum conditions, the compact is heated to 800°C to 900°C at a heating rate of 4°C / min to 6°C / min.

[0107] In the above-mentioned vacuum impurity removal step, heating to 800℃~900℃ and simultaneously drawing a vacuum can remove gaseous impurities that escape from the pressed blank at high temperature.

[0108] In some embodiments, in step S1041 above, the vacuum degree is 10. -3 Below Pa.

[0109] In some embodiments, in step S1041 above, the pressed billet is vacuum-removed from impurities in a vacuum sintering furnace.

[0110] In some embodiments, the vacuum sintering furnace is an OXY-GON furnace from Thermal Technology, USA.

[0111] In some embodiments, a method for preparing the above-described alloy solid solution is provided, comprising the following steps: S11. After the raw materials are made into a compact, they are subjected to solution treatment and powdering to obtain an alloy solid solution; The raw materials include tantalum oxide, titanium carbonitride, tungsten carbide, carbon black, cobalt, chromium nitride, trace metals and rare earth elements; Solution treatment includes molding, degreasing, vacuum impurity removal, and sintering.

[0112] In some embodiments, in step S11 above, the powder preparation includes the following steps: S111. The sintered product is ball-milled.

[0113] In some embodiments, in step S111 above, the ball-to-material ratio of the ball mill is 300:(60~80).

[0114] In some embodiments, in step S111 above, the grinding balls selected in the ball mill are at least one of tungsten carbide balls.

[0115] In some embodiments, in step S111 above, the ball milling process uses a mixture of medium-diameter grinding balls and small-diameter grinding balls, with a ratio of 1:(20~30).

[0116] In some embodiments, the diameter of the medium-diameter grinding ball is 8mm to 10mm.

[0117] In some embodiments, the diameter of the small-diameter grinding ball is 2mm to 5mm.

[0118] In some embodiments, the ball milling time in step S111 is 4 to 6 hours. In this case, the ball mill can produce a powder with uniform coarseness.

[0119] In some embodiments, in step S111 above, the Fsss particle size of the alloy solid solution obtained after ball milling is ≤2.0 μm. In this case, the resulting powder can be thoroughly and uniformly mixed.

[0120] A third aspect of the present invention provides a cemented carbide, the material of which includes the above-described alloy solid solution.

[0121] The cemented carbide provided in this embodiment of the invention contains an alloy solid solution, which significantly increases the thermal shock resistance and hot hardness of the cemented carbide.

[0122] The following description, in conjunction with specific embodiments, provides further details.

[0123] (1) The ball milling involved in the following examples and comparative examples was carried out in a QM-WX horizontal ball mill; vacuum purification, first heating and heat preservation, and second heating and heat preservation were all carried out in a medium frequency vacuum furnace of model VBF-624.

[0124] (2) The titanium carbonitride involved in the following examples and comparative examples is TiC. 0.7 N 0.3 And TiC 0.7 N 0.3 All were prepared using the following methods: According to TiC 0.7 N 0.3 The molar ratio is used to obtain the mass of titanium powder, graphite powder, and urea; Titanium powder, graphite powder and urea were mixed and ball-milled, and then annealed under nitrogen protection. The ball milling ball-to-material (mass) ratio is 20:1, and the annealing temperature is 900℃.

[0125] (3) The polypropylene-based adhesives involved in the following examples and comparative examples are composed of the following components by mass fraction: 10% ethylene-vinyl acetate copolymer, 75% polypropylene, 12% paraffin wax and 3% stearic acid; In the ethylene-vinyl acetate copolymer, the mass fraction of vinyl acetate (VA) is 30%.

[0126] (4) The supercritical fluid involved in the following examples and comparative examples is carbon dioxide supercritical fluid.

[0127] (5) The copper source involved in the following examples and comparative examples is a copper alloy, which is composed of the following components by mass fraction: Sn 10%, Zn 2%, balance is copper and unavoidable impurities.

[0128] Example 1 Example 1 provides an alloy solid solution composed of the following raw materials by weight: 16kg tantalum oxide, 30kg TiC 0.7 N 0.3 50kg tungsten carbide, 4kg carbon black, 8kg cobalt, 0.7kg chromium nitride, 0.05kg indium, and 0.002kg neodymium.

[0129] This embodiment also provides a method for preparing an alloy solid solution, the steps of which are as follows: E1. Preparation of mixtures Tantalum oxide, TiC 0.7 N 0.3 Tungsten carbide, carbon black, cobalt, chromium nitride, indium, and neodymium are mixed and ball-milled to obtain a mixture. The ball-to-material ratio in the ball mill is 100:170, and the grinding balls are a mixture of medium-diameter tungsten carbide balls (8 mm in diameter) and small-diameter tungsten carbide balls (5 mm in diameter) in a ratio of 1:25; the ball milling time is 6 hours.

[0130] E2. Molding The mixture and polypropylene-based binder are mixed and then biaxially pressed to obtain a compact; The amount of polypropylene-based binder is 1% to 1.5% of the mass of the mixture; the pressure of biaxial pressing is 200 MPa.

[0131] E3.Degreasing The compact is degreased under nitrogen protection. The degreasing atmosphere was nitric acid vapor, and the degreasing temperature was 120℃.

[0132] E4. Solution treatment E4-1. Impurity Removal: Under a vacuum degree of 10 -3 Under the condition of Pa, the compact is heated to 800℃ at a heating rate of 5°C / min; E4-2. First heating and holding: Under an argon protective atmosphere with a pressure of 50 kPa, the compact is heated from 800℃ to 2000℃ at a heating rate of 25℃ / min and then held for 100 min.

[0133] E4-3. Supercritical carbon dioxide quenching: The sintered billet obtained by the first heating and holding is placed in supercritical carbon dioxide to cool down to 900℃, and then heated to 1200℃ and held for 1 hour; then cooled down again to below 100℃ using supercritical fluid.

[0134] E4-4. Second heating and holding: Under the protection of argon, the compact is heated to 1350℃ at a heating rate of 10℃ / min and then held for 60min.

[0135] E4-5. Gas quenching: The sintered billet obtained after the second heating and holding is subjected to argon gas quenching to obtain the alloy solid solution of this embodiment; wherein, the gas quenching pressure is 1000kPa±10kPa.

[0136] Example 2 Example 2 provides an alloy solid solution composed of the following raw materials by weight: 15kg tantalum oxide, 15kg TiC 0.7 N 0.3 35kg tungsten carbide, 3kg carbon black, 10kg cobalt, 0.1kg chromium nitride, 0.1kg copper alloy, 0.001kg lanthanum.

[0137] This embodiment also provides a method for preparing an alloy solid solution, the steps of which are basically the same as those in Embodiment 1, except that: In step E4-2, under an argon protective atmosphere with a pressure of 47 kPa, the compact is heated from 900°C to 2100°C at a heating rate of 30°C / min and then held at that temperature for 80 min.

[0138] Example 3 Example 3 provides an alloy solid solution composed of the following raw materials by weight: 17kg tantalum oxide, 20kg TiC 0.7 N 0.3 45kg tungsten carbide, 1kg carbon black, 5kg cobalt, 0.5kg chromium nitride, 0.01kg tin, 0.003kg cerium.

[0139] This embodiment also provides a method for preparing an alloy solid solution, the steps of which are basically the same as those in Embodiment 1, except that: In step E4-2, under an argon protective atmosphere with a pressure of 50 kPa, the compact is heated from 800°C to 2050°C at a heating rate of 30°C / min and then held at that temperature for 60 min.

[0140] Example 4 Example 4 provides an alloy solid solution composed of the following raw materials by weight: 16kg tantalum oxide, 30kg TiC 0.7 N 0.3 50kg tungsten carbide, 4kg carbon black, 8kg cobalt, 0.7kg chromium nitride, 0.05kg tin, 0.05kg copper alloy, 0.001kg cerium, and 0.001kg neodymium.

[0141] This embodiment also provides a method for preparing an alloy solid solution, the steps of which are basically the same as those in Embodiment 1.

[0142] Example 5 Example 5 provides a method for preparing an alloy solid solution, the steps of which are basically the same as those in Example 1, except that: E4-3. Supercritical carbon dioxide quenching: The sintered billet obtained by the first heating and holding is placed in supercritical carbon dioxide to cool down to 800℃, and then heated to 1000℃ and held for 0.5h; then cooled down again to below 100℃ using supercritical fluid.

[0143] Comparative Example 1 Comparative Example 1 provides an alloy solid solution composed of the following raw materials by mass: 16kg tantalum oxide, 30kg TiC 0.7 N 0.3 50 kg tungsten carbide, 4 kg carbon black, 8 kg cobalt and 0.7 kg chromium nitride.

[0144] Comparative Example 1 also provides a method for preparing the alloy provided in this comparative example, the steps of which are basically the same as those in Example 1.

[0145] Comparative Example 2 Comparative Example 2 provides a method for preparing an alloy solid solution, the steps of which are basically the same as those in Example 1, except that: Step E4-3 Supercritical carbon dioxide quenching: The sintered billet obtained from the first heating and holding is placed in supercritical carbon dioxide fluid to cool down to below 100°C.

[0146] Comparative Example 3 Comparative Example 3 provides a method for preparing an alloy solid solution, the steps of which are basically the same as those in Example 1, except that: The solution treatment steps in E4 are as follows: E4-1. Impurity Removal: Under a vacuum degree of 10 -3 Under the condition of Pa, the compact is heated to 800℃ at a heating rate of 5°C / min; E4-2. First heating and holding: Under an argon protective atmosphere with a pressure of 50 kPa, the compact is heated from 800℃ to 2000℃ at a heating rate of 25℃ / min and then held for 100 min.

[0147] E4-3. Gas quenching: The sintered billet obtained after the second heating and holding is subjected to argon gas quenching to obtain the alloy solid solution of this embodiment; wherein, the gas quenching pressure is 1000kPa±10kPa.

[0148] To verify the advancement of the alloy solid solution and its preparation method provided in this invention, cemented carbide tool materials were prepared from the alloy solid solution provided in the embodiments and the alloy provided in the comparative examples under the same process conditions. The Vickers hardness and thermal shock toughness of the tool materials at 800℃ were tested, and the results are shown in Table 1 below. Taking Example 1 as an example, the XRD pattern of the alloy solid solution is shown below. Figure 1 As shown, the SEM images of Examples 1 and 2 are as follows. Figures 2-3 As shown.

[0149] Table 1

[0150] From the table above and the accompanying drawings in the instruction manual, we can draw the following conclusions: (1) In the embodiment, the Vickers hardness of the tool material at 800°C is still as high as 1308HV. It can be seen that the alloy solid solution prepared by the preparation method provided in the embodiment of the present invention can improve the hot hardness of cemented carbide.

[0151] (2) In the embodiment, the impact energy of the tool material at 800°C can reach up to 7.2 J / cm. 3 The lowest is 6.5 J / cm 3 Therefore, the alloy solid solution provided in the embodiments of the present invention has high thermal shock resistance.

[0152] (3) The hardness of the tool material made from the alloys of Example 1 and Comparative Examples 1-3, combined with Figure 1 and Figure 2 It can be seen that the alloy solid solution prepared by the preparation method provided in the embodiments of the present invention has significantly improved the hot hardness of the tool material. This indicates that the preparation method provided in the embodiments of the present invention, after the first heating and holding, supercritical fluid quenching, second heating and holding and gas quenching, obtains a single-phase alloy solid solution with uniform composition, which can significantly improve the hot hardness of the alloy.

[0153] (4) As can be seen from Example 1 and Comparative Example 1, the present invention uses trace amounts of metals and rare earth metals, which can significantly improve the hot hardness of the tool material made of alloy solid solution.

[0154] (5) As can be seen from Examples 1 and 4, doping with various trace metals and rare earths can improve the thermal hardness of the tool material and have little impact on the impact energy.

[0155] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. An alloy solid solution, characterized in that, The raw materials include the following parts by weight: 15-17 parts tantalum oxide, 15-30 parts titanium carbonitride, 45-60 parts tungsten carbide, 1-4 parts carbon black, 5-10 parts cobalt, 0.1-0.7 parts chromium nitride, 0.01-0.1 parts trace metals, 0.001-0.003 parts rare earth elements; The trace metal includes at least one of indium, tin, and copper.

2. The alloy solid solution according to claim 1, characterized in that, The titanium carbonitride includes TiC 0.7 N 0.3 ; And / or, the rare earth element includes at least one of neodymium, lanthanum, and cerium; And / or, the Fisher grain size of the alloy solid solution is less than 2.0 μm.

3. A method for preparing an alloy solid solution as described in claim 1 or 2, characterized in that, Includes the following steps: The pressed billet is subjected to solution treatment to obtain alloy solid solution powder; The raw materials for the pressed blank include tantalum oxide, titanium carbonitride, tungsten carbide, carbon black, cobalt, chromium nitride, trace metals, and rare earth elements.

4. The method for preparing the alloy solid solution according to claim 3, characterized in that, It satisfies at least one of the following characteristics (1) to (2): (1) The solution treatment includes: heating and holding the compact, supercritical fluid quenching, heating and holding the compact and gas quenching steps; (2) The preparation of the pressed blank includes the following steps: mixing the mixture and the binder and then pressing them bidirectionally.

5. The method for preparing the alloy solid solution according to claim 4, characterized in that, It satisfies at least one of the following characteristics (1) to (11): (1) The first heating and heat preservation step includes: heating the compact to 2000℃~2100℃ under an inert protective atmosphere at a heating rate of 20℃ / min~30℃ / min and then heat preservation; (2) In the supercritical fluid quenching, the supercritical fluid includes supercritical carbon dioxide; (3) The supercritical fluid quenching step includes: After the sintered billet obtained by the first heating and holding is placed in a supercritical fluid to cool down to 800℃~900℃, it is then heated to 1000℃~1200℃ and held for a period of time, and then cooled down again to below 100℃ using a supercritical fluid. (4) The second heating and heat preservation step includes: heating the compact to 1350℃~1400℃ under an inert protective atmosphere at a heating rate of 10℃ / min~20℃ / min and then heat preservation; (5) The pressure of the gas quenching is 1000 kPa ± 10 kPa; (6) In the gas quenching process, the gas used includes at least one of argon and helium; (7) The solution treatment further includes the following steps: vacuum cleaning the pressed blank; (8) The amount of the adhesive used is 1% to 1.5% of the mass of the mixture; (9) The adhesive includes a polypropylene-based adhesive; (10) The pressure of the bidirectional compression is 200MPa~210MPa; (11) The preparation of the compact also includes the following steps: degreasing the compact obtained by bidirectional pressing.

6. The method for preparing the alloy solid solution according to claim 5, characterized in that, It satisfies at least one of the following characteristics (1) to (9): (1) During the first heating and heat preservation, the pressure of the inert protective atmosphere is 47 kPa to 50 kPa; (2) In the first heating and heat preservation process, the heat preservation time is 60 min to 120 min; (3) In the supercritical fluid quenching, the holding time at 1000℃~1200℃ is 0.5h~1h; (4) During the second heating and heat preservation process, the pressure of the inert protective atmosphere is atmospheric pressure; (5) During the second heating and heat preservation process, the heat preservation time is 30 min to 60 min; (6) The preparation of the mixture includes the following steps: ball milling and mixing the raw materials of the mixture; (7) The polypropylene-based adhesive is a mixture of ethylene-vinyl acetate copolymer, polypropylene, paraffin wax and stearic acid; (8) The degreasing atmosphere is nitric acid vapor; (9) The degreasing temperature is 120℃~130℃.

7. The method for preparing the alloy solid solution according to claim 6, characterized in that, It satisfies at least one of the following characteristics (1) to (2): (1) The ball milling mixing step includes: after the first ball milling of tantalum oxide, titanium carbonitride, tungsten carbide and carbon black, cobalt, chromium nitride, trace metals and rare earth are added for the second ball milling; (2) The polypropylene-based adhesive is composed of the following components by mass fraction: 10%~20% ethylene-vinyl acetate copolymer, 62%~75% polypropylene, 10%~15% paraffin wax and 1%~3% stearic acid.

8. The method for preparing the alloy solid solution according to claim 7, characterized in that, It satisfies at least one of the following characteristics (1) to (5): (1) The ball-to-material ratio of the first ball mill is 100:160~180; (2) The ball-to-material ratio of the second ball mill is 100:160~180; (3) The first ball milling time is 6h~7h; (4) The second ball milling time is 6h~7h; (5) In the ethylene-vinyl acetate copolymer, the mass fraction of vinyl acetate is 25%~40%.

9. A cemented carbide, characterized in that, The material includes the alloy solid solution as described in claim 1 or 2.

10. An application of the cemented carbide as described in claim 9 in the field of cutting tools.

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