High-entropy dual-phase cermet tool material and preparation method thereof

Abstract

The application relates to the technical field of cermet materials, and discloses a high-entropy dual-phase cermet tool material and a preparation method thereof.The raw material of the high-entropy dual-phase cermet tool material comprises 30-60 parts by weight of high-entropy ceramic phase metal powder, 40-70 parts by weight of high-entropy alloy phase powder and 0.5-2 parts by weight of guanidine graphene; the high-entropy alloy phase powder comprises Fe powder, Co powder, Ni powder, Cr powder and Mn powder; the guanidine graphene contains a large number of Schiff base guanidine groups on the surface, forms an iron-cobalt-nickel alloy layer on the surface of the high-entropy ceramic phase metal powder, and forms a strong chemical coordination effect with metal elements such as iron, cobalt and nickel in the high-entropy alloy phase powder, so that the interface strength is improved; and a three-stage sintering process is adopted, so that the material has higher compression strength, Rockwell hardness and fracture toughness.

Description

Technical Field

[0001] This invention relates to the field of metal ceramic materials technology, specifically to a high-entropy biphase metal ceramic tooling material and its preparation method. Background Technology

[0002] With the rapid development of modern industry, the performance requirements for tooling and die materials are becoming increasingly stringent. Traditional cermet tooling and die materials (such as WC-Co cemented carbide) suffer from problems such as rapid strength decay at high temperatures and poor thermal shock resistance. Their overall performance in key properties such as hardness, toughness, wear resistance, and high-temperature stability is also subpar, often failing to meet the demands of complex working conditions and high-intensity applications. In recent years, high-entropy materials have attracted attention due to their unique performance advantages. The emergence of high-entropy alloys and high-entropy ceramics has brought new opportunities to solve these problems.

[0003] However, most existing high-entropy cermet materials adopt a "high-entropy ceramic + conventional alloy" structure, which still has shortcomings in the control and optimization of phase structure, failing to fully realize the potential of high-entropy materials. At the same time, high-entropy materials face densification challenges during sintering, and the low bonding strength at the ceramic-metal interface affects the overall performance of the material. Therefore, developing a high-performance high-entropy biphase cermet tooling material with innovative structure and preparation process has significant practical significance and application value.

[0004] The current technological bottlenecks are: it is difficult to balance strength and toughness in a single high-entropy phase; traditional sintering processes cannot achieve interfacial compatibility control of high-entropy ceramics / metals; and the lack of cross-scale structural design leads to insufficient high-temperature performance. Summary of the Invention

[0005] Technical problem solved: In view of the shortcomings of the prior art, the present invention provides a high-strength, high-hardness, high-entropy biphase metal-ceramic mold material and its preparation method.

[0006] The technical solution of the present invention is as follows: a high-entropy biphase metal-ceramic mold material and its preparation method, wherein the raw materials include 30-60 parts by weight of high-entropy ceramic phase metal powder, 40-70 parts by weight of high-entropy alloy phase powder, and 0.5-2 parts by weight of guanidine graphene; wherein the high-entropy alloy phase powder includes any one or combination of Fe powder, Co powder, Ni powder, Cr powder, and Mn powder.

[0007] The preparation method of high-entropy biphase metal-ceramic tooling material is as follows:

[0008] (1) Add graphene oxide to N,N-dimethylformamide, disperse by ultrasonication, add 5-hydroxyisophthalaldehyde guanidine, 4-dimethylaminopyridine and dicyclohexylcarbodiimide, stir to carry out esterification reaction, filter, wash filter cake with water and ethanol, dry to obtain guanidine graphene.

[0009] (2) The Ti powder, V powder, Nb powder, Zr powder and Hf powder are ball-milled and mixed, placed in a sintering furnace, sintered in an inert atmosphere, cooled and then ball-milled to obtain high-entropy ceramic phase powder.

[0010] (3) Add ferrous sulfate, cobalt sulfate, nickel sulfate and sodium phosphite to deionized water to prepare a chemical plating solution. Add high-entropy ceramic phase powder, stir and react, filter, wash with water and dry to obtain high-entropy ceramic phase metal powder. Chemically plate the surface of the high-entropy ceramic phase powder with a high-entropy alloy phase metal layer, and control the thickness of the coating to 60-100nm to form a core-shell structured composite powder.

[0011] (4) High-entropy alloy phase powder, high-entropy ceramic phase metal powder, and guanidine graphene are ball-milled and mixed, and then placed in a sintering furnace for sintering using a three-stage sintering process. Specifically, the mixture is first heated to 600-700℃ in a vacuum environment at a heating rate of 5-10℃ / min and held for 30-45min to allow the adsorbed gas in the powder to be fully discharged. At the same time, the guanidine groups of graphene undergo physical adsorption and chemical coordination with the metal elements on the surface of the metal powder. Then, the mixture is heated to 1000-1100℃ at a heating rate of 10-15℃ / min. The high-entropy alloy phase coating in the core-shell structure begins to partially melt and initially combine with the high-entropy ceramic phase powder. At the same time, graphene further diffuses to the ceramic / metal interface, enhancing the interfacial bonding. Finally, argon gas is introduced, and the pressure in the sintering furnace is controlled at 30-50 MPa. The temperature is increased to 1200-1400℃ at a heating rate of 3-5℃ / min and held for 10-20 minutes to fully densify the powder, forming a high-entropy dual-phase metal-ceramic preform. After cooling, the high-entropy dual-phase metal-ceramic mold material is obtained.

[0012] Furthermore, (1) the reaction temperature is 45-60℃ and the reaction time is 18-36h.

[0013] Furthermore, in (1), the mass ratio of graphene oxide, 5-hydroxyisophthalaldehyde guanidine, 4-dimethylaminopyridine, and dicyclohexylcarbodiimide is 100:(10-60):(9-58):(2-13).

[0014] Furthermore, in (2), the mass ratio of Ti powder, V powder, Nb powder, Zr powder, and Hf powder is (46-54):(22-36):(15-22):(1-4):(0.5-1.2).

[0015] Furthermore, in (2), the inert atmosphere is nitrogen or argon, the pressure in the sintering furnace is 30-40 MPa, the sintering temperature is 1100-1300℃, and the sintering time is 1-1.5h.

[0016] Furthermore, in (3), the concentration of ferrous sulfate in the electroless plating solution is 14-33 g / L, the concentration of cobalt sulfate is 6-14 g / L, the concentration of nickel sulfate is 10-22 g / L, and the concentration of sodium phosphite is 11-27 g / L.

[0017] Furthermore, in (3), the reaction temperature is 75-90℃ and the reaction time is 60-90min.

[0018] Furthermore, (4) the mass ratio of Fe powder, Co powder, Ni powder, Cr powder and Mn powder in the high entropy alloy phase powder is (47-55):(13-20):(16-25):(4-9):(3-7).

[0019] Further, the preparation method of 5-hydroxy-isophthalaldehyde aminoguanidine is as follows: 5-hydroxy-isophthalaldehyde and aminoguanidine bicarbonate are added to ethanol in a molar ratio of 1:(2.4-2.8), and a hydrochloric acid solution with a mass fraction of 30-37% is added dropwise. The mixture is heated to 65-75℃, refluxed for 5-7 hours, and distilled under reduced pressure. The product is added to a saturated sodium bicarbonate aqueous solution, extracted with ethyl acetate, and the organic phase is distilled under reduced pressure. The product is recrystallized in ethanol to obtain 5-hydroxy-isophthalaldehyde aminoguanidine.

[0020] The beneficial technical effects of this invention are as follows: This invention involves the esterification reaction of the hydroxyl groups of 5-hydroxyisophthalaldehyde with the carboxyl groups on the surface of graphene oxide to obtain guanidine graphene, thereby introducing a large number of Schiff base guanidine groups onto the surface of graphene.

[0021] This invention uses Ti powder, V powder, Nb powder, Zr powder, and Hf powder as high-entropy ceramic phases, and forms an iron-cobalt-nickel alloy layer on the surface through chemical plating, creating a unique core-shell structure. This is then combined with Fe-Co-Ni-Cr-Mn high-entropy alloy phase powder and guanidine graphene through a three-stage sintering process to obtain a high-entropy dual-phase metal-ceramic mold material. The iron-cobalt-nickel alloy layer formed on the surface of the core-shell structured high-entropy ceramic phase metal powder improves the interfacial compatibility between the high-entropy ceramic phase metal powder and the Fe-Co-Ni-Cr-Mn high-entropy alloy phase powder, promoting element diffusion and interfacial bonding during sintering. This helps solve the problem of densification during the sintering of high-entropy materials, thereby improving the internal density and mechanical properties of the material.

[0022] The guanidine-based graphene of this invention contains a large number of Schiff base guanidine groups on its surface, which form an iron-cobalt-nickel alloy layer with the surface of the high-entropy ceramic phase metal powder, and form a strong chemical coordination effect with the iron, cobalt, nickel and other metal elements in the high-entropy alloy phase powder. This improves the interfacial strength between graphene and the high-entropy ceramic phase metal powder and the high-entropy alloy phase powder. At the same time, it better promotes the formation of a metal-ceramic carbide reinforcing phase between graphene and the high-entropy ceramic phase metal powder and the high-entropy alloy phase powder during high-temperature sintering, further improving the mechanical strength of the material.

[0023] This invention employs a three-stage sintering process. In the first stage of sintering, the adsorbed gases in the metal powder are fully discharged, while the guanidine groups of graphene undergo physical adsorption and chemical coordination with the metal elements on the surface of the metal powder. In the second stage of sintering, the high-entropy alloy phase coating in the core-shell structure begins to partially melt and initially combines with the high-entropy ceramic phase powder. Simultaneously, graphene further diffuses to the ceramic / metal interface, enhancing the interfacial bonding. In the third stage of sintering, the metal powder is fully densified, forming a high-entropy dual-phase metal-ceramic preform. By rationally controlling the heating rate and holding sintering time, the sintering efficiency and material density are improved, resulting in higher compressive strength, Rockwell hardness, and fracture toughness. Attached Figure Description

[0024] Figure 1 It is the electron microstructure of high-entropy biphase metal-ceramic mold material.

[0025] Figure 2 This is an elemental distribution diagram of a high-entropy biphase metal-ceramic mold material. Detailed Implementation

[0026] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0027] Example 1:

[0028] (1) Add 15 mmol of 5-hydroxy-isophthalaldehyde and 36 mmol of aminoguanidine bicarbonate to 60 mL of ethanol, add 4 mL of 30% hydrochloric acid solution dropwise, heat to 65 °C, reflux for 7 h, distill under reduced pressure, add the product to a saturated sodium bicarbonate aqueous solution, extract with ethyl acetate, distill the organic phase under reduced pressure, and recrystallize the product in ethanol to obtain 5-hydroxy-isophthalaldehyde aminoguanidine. The reaction formula is:

[0029]

[0030] (2) Add 200 mg of graphene oxide to 150 mL of N,N-dimethylformamide, disperse by ultrasonication, then add 20 mg of 5-hydroxy-isophthalaldehyde guanidine, 18 mg of 4-dimethylaminopyridine and 4 mg of dicyclohexylcarbodiimide. Stir the mixture at 45 °C for 24 h, filter, wash the filter cake with water and ethanol, and dry to obtain guanidine graphene.

[0031] (3) 522g Ti powder, 276g V powder, 180g Nb powder, 15g Zr powder and 7g Hf powder were ball-milled and mixed, placed in a sintering furnace, heated to 1200℃ at a heating rate of 10℃ / min in an argon atmosphere, held for sintering for 1.5h, and controlled the pressure of the sintering furnace at 30MPa. After cooling, the mixture was ball-milled to obtain high-entropy ceramic phase powder.

[0032] (4) Add 14g of ferrous sulfate, 6g of cobalt sulfate, 10g / L of nickel sulfate and 11g / L of sodium phosphite to 1L of deionized water to prepare a chemical plating solution. Add 2.5kg of high-entropy ceramic phase powder, heat to 80℃, stir and react for 60min, filter, wash with water and dry to obtain core-shell structured high-entropy ceramic phase metal powder.

[0033] (5) 600g of high-entropy alloy phase powder composed of Fe powder, Co powder, Ni powder, Cr powder and Mn powder in a mass ratio of 49:20:18:9:4, 400g of core-shell high-entropy ceramic phase metal powder and 5g of guanidine graphene were ball-milled and mixed for 60min. Then the mixture was placed in a sintering furnace and sintered using a three-stage sintering process. Specifically, under vacuum, the temperature was raised to 650℃ at a heating rate of 5℃ / min and held for 45min. Then the temperature was raised to 1000℃ at a heating rate of 15℃ / min and held for 25min. Finally, argon gas was introduced and the pressure in the sintering furnace was controlled at 40MPa. The temperature was raised to 1300℃ at a heating rate of 5℃ / min and held for 10min. The mixture was then cooled to obtain high-entropy dual-phase metal ceramic mold material.

[0034] Example 2:

[0035] (1) Add 15 mmol of 5-hydroxy-isophthalaldehyde and 42 mmol of aminoguanidine bicarbonate to 80 mL of ethanol, add 3 mL of 37% hydrochloric acid solution, heat to 75 °C, reflux for 5 h, distill under reduced pressure, add the product to saturated sodium bicarbonate aqueous solution, extract with ethyl acetate, distill under reduced pressure, recrystallize the product in ethanol to obtain 5-hydroxy-isophthalaldehyde aminoguanidine.

[0036] (2) Add 200 mg of graphene oxide to 200 mL of N,N-dimethylformamide, disperse by ultrasonication, then add 80 mg of 5-hydroxy-isophthalaldehyde guanidine, 74 mg of 4-dimethylaminopyridine and 17 mg of dicyclohexylcarbodiimide. Stir the mixture at 60 °C for 18 h, filter, wash the filter cake with water and ethanol, and dry to obtain guanidine graphene.

[0037] (3) 467g Ti powder, 360g V powder, 150g Nb powder, 18g Zr powder and 5g Hf powder were ball-milled and mixed, placed in a sintering furnace, heated to 1100℃ at a heating rate of 10℃ / min in a nitrogen atmosphere, held for sintering for 1.5h, and controlled the pressure of the sintering furnace at 30MPa. After cooling, the mixture was ball-milled to obtain high-entropy ceramic phase powder.

[0038] (4) Add 33g ferrous sulfate, 14g cobalt sulfate, 22g / L nickel sulfate and 27g / L sodium phosphite to 1L deionized water to prepare a chemical plating solution. Add 3kg high-entropy ceramic phase powder, heat to 75℃, stir and react for 90min, filter, wash with water and dry to obtain core-shell structured high-entropy ceramic phase metal powder.

[0039] (5) 400g of high-entropy alloy phase powder composed of Fe powder, Co powder, Ni powder, Cr powder and Mn powder in a mass ratio of 47:16:25:9:3, 600g of core-shell high-entropy ceramic phase metal powder and 15g of guanidine graphene were ball-milled and mixed for 30min. Then the mixture was placed in a sintering furnace and sintered using a three-stage sintering process. Specifically, under vacuum, the temperature was raised to 700℃ at a heating rate of 10℃ / min and held for 30min. Then the temperature was raised to 1100℃ at a heating rate of 15℃ / min and held for 20min. Finally, argon gas was introduced and the pressure in the sintering furnace was controlled at 50MPa. The temperature was raised to 1200℃ at a heating rate of 3℃ / min and held for 20min. The mixture was then cooled to obtain high-entropy dual-phase metal ceramic mold material.

[0040] Example 3:

[0041] (1) Add 200 mg of graphene oxide to 200 mL of N,N-dimethylformamide, disperse by ultrasonication, and then add 120 mg of 5-hydroxy-isophthalaldehyde guanidine (prepared from Example 1), 116 mg of 4-dimethylaminopyridine, and 26 mg of dicyclohexylcarbodiimide. Stir the mixture at 50 °C for 36 h, filter, wash the filter cake with water and ethanol, and dry to obtain guanidine graphene.

[0042] (2) 539g Ti powder, 223g V powder, 186g Nb powder, 40g Zr powder and 12g Hf powder were ball-milled and mixed, placed in a sintering furnace, heated to 1300℃ at a heating rate of 15℃ / min in an argon atmosphere, held for sintering for 1h, and controlled the pressure of the sintering furnace to be 30MPa. After cooling, the mixture was ball-milled to obtain high-entropy ceramic phase powder.

[0043] (3) Add 20g ferrous sulfate, 8g cobalt sulfate, 14g / L nickel sulfate and 17g / L sodium phosphite to 1L deionized water to prepare a chemical plating solution. Add 2kg high-entropy ceramic phase powder, heat to 80℃, stir and react for 60min, filter, wash with water and dry to obtain core-shell structured high-entropy ceramic phase metal powder.

[0044] (4) 700g of high-entropy alloy phase powder composed of Fe powder, Co powder, Ni powder, Cr powder and Mn powder in a mass ratio of 55:17:16:5:7, 300g of core-shell high-entropy ceramic phase metal powder and 20g of guanidine graphene were ball-milled and mixed for 60min. Then the mixture was placed in a sintering furnace and sintered using a three-stage sintering process. Specifically, under vacuum, the temperature was raised to 600℃ at a heating rate of 5℃ / min and held for 45min. Then the temperature was raised to 1000℃ at a heating rate of 10℃ / min and held for 15min. Finally, argon gas was introduced and the pressure in the sintering furnace was controlled at 30MPa. The temperature was raised to 1400℃ at a heating rate of 5℃ / min and held for 10min. The mixture was then cooled to obtain high-entropy dual-phase metal ceramic mold material.

[0045] Example 4:

[0046] (1) Add 200 mg of graphene oxide to 150 mL of N,N-dimethylformamide, disperse by ultrasonication, and then add 50 mg of 5-hydroxy-isophthalaldehyde guanidine (prepared from Example 1), 46 mg of 4-dimethylaminopyridine, and 10 mg of dicyclohexylcarbodiimide. Stir the mixture at 45 °C for 36 h, filter, wash the filter cake with water and ethanol, and dry to obtain guanidine graphene.

[0047] (2) 493g Ti powder, 335g V powder, 150g Nb powder, 10g Zr powder and 12g Hf powder were ball-milled and mixed, placed in a sintering furnace, heated to 1200℃ at a heating rate of 10℃ / min in an argon atmosphere, held for sintering for 1.5h, and controlled the pressure of the sintering furnace at 40MPa. After cooling, the mixture was ball-milled to obtain high-entropy ceramic phase powder.

[0048] (3) Add 27g ferrous sulfate, 11g cobalt sulfate, 18g / L nickel sulfate and 22g / L sodium phosphite to 1L deionized water to prepare a chemical plating solution. Add 3kg high-entropy ceramic phase powder, heat to 75℃, stir and react for 90min, filter, wash with water and dry to obtain core-shell structured high-entropy ceramic phase metal powder.

[0049] (4) 500g of high-entropy alloy phase powder composed of Fe powder, Co powder, Ni powder, Cr powder and Mn powder in a mass ratio of 54:13:23:4:6, 500g of core-shell high-entropy ceramic phase metal powder and 10g of guanidine graphene were ball-milled and mixed for 60min. Then the mixture was placed in a sintering furnace and sintered using a three-stage sintering process. Specifically, under vacuum, the temperature was raised to 600℃ at a heating rate of 10℃ / min and held for 45min. Then the temperature was raised to 1000℃ at a heating rate of 10℃ / min and held for 15min. Finally, argon gas was introduced and the pressure in the sintering furnace was controlled at 40MPa. The temperature was raised to 1300℃ at a heating rate of 5℃ / min and held for 10min. The mixture was then cooled to obtain high-entropy dual-phase metal ceramic mold material.

[0050] Comparative Example 1 differs from Example 1 in that graphene oxide is used instead of guanidine graphene.

[0051] (1) 600g of high-entropy alloy phase powder composed of Fe powder, Co powder, Ni powder, Cr powder and Mn powder in a mass ratio of 49:20:18:9:4, 400g of core-shell structured high-entropy ceramic phase metal powder (prepared by Example 1) and 5g of graphene oxide were ball-milled and mixed for 60min. Then the mixture was placed in a sintering furnace and sintered using a three-stage sintering process. Specifically, under vacuum, the temperature was raised to 650℃ at a heating rate of 5℃ / min and held for 45min. Then the temperature was raised to 1000℃ at a heating rate of 15℃ / min and held for 25min. Finally, argon gas was introduced and the pressure in the sintering furnace was controlled at 40MPa. The temperature was raised to 1300℃ at a heating rate of 5℃ / min and held for 10min. The mixture was then cooled to obtain high-entropy dual-phase metal ceramic mold material.

[0052] Comparative Example 2 differs from Comparative Example 1 and Example 1 in that 4-hydroxybenzaldehyde aminoguanidine is used instead of 5-hydroxyisophthalaldehyde aminoguanidine.

[0053] (1) Add 15 mmol of 4-hydroxybenzaldehyde and 18 mmol of aminoguanidine bicarbonate to 60 mL of ethanol, add 2 mL of 30% hydrochloric acid solution dropwise, heat to 65 °C, reflux for 7 h, distill under reduced pressure, add the product to a saturated sodium bicarbonate aqueous solution, extract with ethyl acetate, distill the organic phase under reduced pressure, and recrystallize the product in ethanol to obtain 4-hydroxybenzaldehyde aminoguanidine. The structural formula is...

[0054]

[0055] (2) Add 200 mg of graphene oxide to 150 mL of N,N-dimethylformamide, disperse by ultrasonication, then add 20 mg of 4-hydroxybenzaldehyde guanidine, 18 mg of 4-dimethylaminopyridine and 4 mg of dicyclohexylcarbodiimide. Stir the mixture at 45 °C for 24 h, filter, wash the filter cake with water and ethanol, and dry to obtain guanidine graphene.

[0056] (3) 600g of high-entropy alloy phase powder composed of Fe powder, Co powder, Ni powder, Cr powder and Mn powder in a mass ratio of 49:20:18:9:4, 400g of core-shell structure high-entropy ceramic phase metal powder (prepared from Example 1) and 5g of guanidine graphene were ball-milled and mixed for 60min. Then the mixture was placed in a sintering furnace and sintered using a three-stage sintering process. Specifically, under vacuum, the temperature was raised to 650℃ at a heating rate of 5℃ / min and held for 45min. Then the temperature was raised to 1000℃ at a heating rate of 15℃ / min and held for 25min. Finally, argon gas was introduced and the pressure in the sintering furnace was controlled at 40MPa. The temperature was raised to 1300℃ at a heating rate of 5℃ / min and held for 10min. The mixture was then cooled to obtain high-entropy dual-phase metal ceramic mold material.

[0057] Comparative Example 3 differs from Comparative Example 1 and Example 1 in that high-entropy ceramic phase powder is used instead of core-shell high-entropy ceramic phase metal powder.

[0058] (1) 522g Ti powder, 276g V powder, 180g Nb powder, 15g Zr powder and 7g Hf powder were ball-milled and mixed, placed in a sintering furnace, heated to 1200℃ at a heating rate of 10℃ / min in an argon atmosphere, held for sintering for 1.5h, and controlled the pressure of the sintering furnace at 30MPa. After cooling, the mixture was ball-milled to obtain high-entropy ceramic phase powder.

[0059] (2) 600g of high-entropy alloy phase powder composed of Fe powder, Co powder, Ni powder, Cr powder and Mn powder in a mass ratio of 49:20:18:9:4, 400g of high-entropy ceramic phase powder and 5g of guanidine graphene were ball-milled and mixed for 60min. Then the mixture was placed in a sintering furnace and sintered using a three-stage sintering process. Specifically, under vacuum, the temperature was raised to 650℃ at a heating rate of 5℃ / min and held for 45min. Then the temperature was raised to 1000℃ at a heating rate of 15℃ / min and held for 25min. Finally, argon gas was introduced and the pressure in the sintering furnace was controlled at 40MPa. The temperature was raised to 1300℃ at a heating rate of 5℃ / min and held for 10min. The mixture was then cooled to obtain high-entropy biphase metal ceramic mold material.

[0060] Comparative Example 4, without the three-stage sintering process.

[0061] (1) 600g of high-entropy alloy phase powder composed of Fe powder, Co powder, Ni powder, Cr powder and Mn powder in a mass ratio of 49:20:18:9:4, 400g of core-shell high-entropy ceramic phase metal powder (prepared by Example 1) and 5g of guanidine graphene (prepared by Example 1) were ball-milled and mixed for 60min. Then the mixture was placed in a sintering furnace, argon gas was introduced, and the pressure in the sintering furnace was controlled at 40MPa. The temperature was raised to 1300℃ at a heating rate of 5℃ / min, held for 10min, and then cooled to obtain high-entropy dual-phase metal ceramic mold material.

[0062] The compressive strength of the material is tested according to standard GB / T 23370-2009. The Rockwell hardness is tested according to standard GB / T 3849.1-2015. The fracture toughness is tested according to standard GB / T 21143-2014.

[0063] Table 1 Material Performance Tests

[0064]

[0065] Testing revealed that Examples 1-4 exhibited higher compressive strength, Rockwell hardness, and fracture toughness. This was primarily due to the formation of an iron-cobalt-nickel alloy layer on the surface of the high-entropy ceramic phase metal powder via chemical plating. This unique core-shell structure improved the interfacial compatibility between the high-entropy ceramic phase metal powder and the Fe-Co-Ni-Cr-Mn high-entropy alloy phase powder, promoting element diffusion and interfacial bonding during sintering. This process helps solve the densification problem in high-entropy materials, thereby improving the internal density and mechanical properties of the material. Furthermore, the added guanidine-based graphene contained a large number of Schiff base guanidine groups on its surface. The graphene forms an iron-cobalt-nickel alloy layer on the surface of the high-entropy ceramic phase metal powder, and the iron, cobalt, and nickel metal elements in the high-entropy alloy phase powder form a strong chemical coordination effect, thereby improving the interfacial strength between graphene and the high-entropy ceramic phase metal powder and the high-entropy alloy phase powder. At the same time, it better promotes the formation of a metal-ceramic carbide reinforcing phase between graphene and the high-entropy ceramic phase metal powder and the high-entropy alloy phase powder during high-temperature sintering, further improving the mechanical strength of the material. Furthermore, by adopting a three-stage sintering process, the physicochemical changes at different temperature stages are observed, and the heating rate and holding time are reasonably controlled, which improves the sintering efficiency and the compactness of the material, making the material exhibit higher compressive strength, Rockwell hardness, and fracture toughness.

[0066] In Comparative Example 1, ordinary graphene oxide was added. The chemical coordination between graphene oxide and high-entropy ceramic phase metal powder and high-entropy alloy phase powder was weak, the interfacial strength was low, and the reinforcing effect was poor. As a result, the compressive strength, Rockwell hardness and fracture toughness of the material were lower than those of Example 1.

[0067] Comparative Example 2's 4-hydroxybenzaldehyde guanidine acetal contains only one Schiff base guanidine group, resulting in a lower Schiff base guanidine group content in the prepared guanidine graphene compared to the guanidine graphene in Example 1. Consequently, the chemical coordination and interfacial strength between the graphene and the high-entropy ceramic phase metal powder and the high-entropy alloy phase powder are lower than in Example 1, and the reinforcing effect of graphene is poor, leading to lower compressive strength, Rockwell hardness, and fracture toughness of the material compared to Example 1.

[0068] The high-entropy ceramic phase powder of Comparative Example 3 was not subjected to iron-cobalt-nickel electroless plating, thus it did not form a core-shell structure and did not improve the interfacial compatibility with the high-entropy alloy phase powder, resulting in the mechanical properties of the material being lower than those of Example 1.

[0069] Comparative Example 4 did not employ a three-stage sintering process, and the mechanical properties of the material were lower than those of Example 1.

[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-entropy biphase metal-ceramic tooling material, characterized in that, The raw materials of the high-entropy biphase metal-ceramic mold material include 30-60 parts by weight of high-entropy ceramic phase metal powder, 40-70 parts by weight of high-entropy alloy phase powder, and 0.5-2 parts by weight of guanidine graphene. The preparation method of the high-entropy ceramic phase metal powder is as follows: (1) The Ti powder, V powder, Nb powder, Zr powder and Hf powder are ball-milled and mixed, placed in a sintering furnace, sintered in an inert atmosphere, cooled and then ball-milled to obtain high-entropy ceramic phase powder; (2) Add ferrous sulfate, cobalt sulfate, nickel sulfate and sodium phosphite to deionized water to prepare a chemical plating solution. Add high-entropy ceramic phase powder, stir and react, filter, wash with water and dry to obtain high-entropy ceramic phase metal powder. The preparation method of the guanidine graphene is as follows: graphene oxide is added to N,N-dimethylformamide, ultrasonically dispersed, and then 5-hydroxyisophthalaldehyde acetal aminoguanidine, 4-dimethylaminopyridine and dicyclohexylcarbodiimide are added. After stirring and reacting, the mixture is filtered, the filter cake is washed with water and ethanol, and dried to obtain guanidine graphene. The high-entropy alloy phase powder includes any one or a combination of Fe powder, Co powder, Ni powder, Cr powder, and Mn powder; The mass ratio of Ti powder, V powder, Nb powder, Zr powder, and Hf powder in (1) is (46-54):(22-36):(15-22):(1-4):(0.5-1.2); The concentration of ferrous sulfate in the electroless plating solution in (2) is 14-33 g / L, the concentration of cobalt sulfate is 6-14 g / L, the concentration of nickel sulfate is 10-22 g / L, and the concentration of sodium phosphite is 11-27 g / L. The mass ratio of graphene oxide, 5-hydroxyisophthalaldehyde guanidine, 4-dimethylaminopyridine, and dicyclohexylcarbodiimide is 100:(10-60):(9-58):(2-13); The mass ratio of Fe powder, Co powder, Ni powder, Cr powder, and Mn powder in the high-entropy alloy phase powder is (47-55):(13-20):(16-25):(4-9):(3-7).

2. The high-entropy biphase metal-ceramic tooling material according to claim 1, characterized in that, In step (1), the inert atmosphere is nitrogen or argon, the pressure in the sintering furnace is 30-40 MPa, the sintering temperature is 1100-1300℃, and the sintering time is 1-1.5h.

3. The high-entropy biphase metal-ceramic tooling material according to claim 1, characterized in that, The reaction temperature in (2) is 75-90℃ and the reaction time is 60-90min.

4. The high-entropy biphase metal-ceramic tooling material according to claim 1, characterized in that, In the preparation method of the guanidinographene, the reaction temperature is 45-60℃ and the reaction time is 18-36h.

5. The high-entropy biphase metal-ceramic tooling material according to claim 1, characterized in that, The preparation method of the 5-hydroxy-isophthalaldehyde aminoguanidine is as follows: 5-hydroxy-isophthalaldehyde and aminoguanidine bicarbonate are added to ethanol in a molar ratio of 1:(2.4-2.8), and a 30-37% hydrochloric acid solution is added dropwise. The mixture is heated to 65-75℃, refluxed for 5-7 hours, and distilled under reduced pressure. The product is added to a saturated sodium bicarbonate aqueous solution and extracted with ethyl acetate. The organic phase is then distilled under reduced pressure, and the product is recrystallized in ethanol to obtain 5-hydroxy-isophthalaldehyde aminoguanidine.

6. A method for preparing a high-entropy biphase metal-ceramic tooling material as described in any one of claims 1-5, characterized in that, The preparation method includes: ball milling and mixing high-entropy alloy phase powder, high-entropy ceramic phase metal powder, and guanidine graphene, then placing the mixture in a sintering furnace, heating it to 600-700℃ at a heating rate of 5-10℃ / min under vacuum, and holding it at that temperature for 30-45min; then heating it to 1000-1100℃ at a heating rate of 10-15℃ / min and holding it at that temperature for 15-25min; finally, introducing argon gas and controlling the pressure in the sintering furnace to 30-50MPa, heating it to 1200-1400℃ at a heating rate of 3-5℃ / min, holding it at that temperature for 10-20min, and then cooling it to obtain a high-entropy dual-phase metal-ceramic mold material.

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