Preparation method of high-entropy alloy binding phase hard alloy

Abstract

The invention discloses a high-entropy alloy binding phase hard alloy and a preparation method thereof, and belongs to the technical field of hard alloy materials. The method comprises the steps that FeCoCrNiMo0. 3 high-entropy alloy powder is subjected to refining pretreatment through planetary ball milling till the particle size ranges from 0.5 m to 3 m, then the FeCoCrNiMo0. 3 high-entropy alloy powder is mixed with 1-5 m TiC powder according to the proportion of 35-48 wt%, mechanical alloying is conducted for 4-8 h under the conditions that the ball-to-material ratio is 1: 1 and the rotating speed ranges from 300 rpm to 400 rpm, and mixed powder is obtained; the mixed powder is heated to 900-1050 DEG C at the speed of 10 DEG C / min under argon protection, heat preservation is conducted for 2 h, and axial oscillation pressure of 65 + / -5 MPa and 50 Hz is applied for sintering; and then annealing is conducted at 550-570 DEG C for 6 h, gas quenching solid solution is conducted at 1000-1100 DEG C for 30-60 min, and aging treatment is conducted at 550-600 DEG C for 1-3 h. The obtained hard alloy has the hardness HRC of 60-63, the bending strength of 3180-3800 MPa and the impact toughness of 24-28 J, has excellent red hardness, corrosion resistance and high-temperature stability, and is suitable for wear-resistant parts in petrochemical engineering, ocean engineering and mine equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hard alloy materials, and particularly relates to a preparation method of high-entropy alloy binder phase hard alloy BACKGROUND

[0002] As a key material in modern industry, hard alloy is widely used in wear-resistant parts under harsh working conditions due to its high hardness, excellent wear resistance and sufficient strength. In the fields of petroleum and chemical industry and ocean engineering, the sealing ring of the pump, the valve part and the key wear-resistant surface of the drilling equipment not only bear the severe erosion and wear of the mud medium, but also are exposed to the corrosion environment of seawater and chemical medium for a long time. Meanwhile, in the energy industry, the screw conveyor lining plate, nozzle and other parts in the coal and ore conveying system also continuously face the dual action of abrasive wear and humid corrosion environment. These complex working conditions put high requirements on the comprehensive performance of hard alloy.

[0003] However, the traditional hard alloy with cobalt or iron-manganese-nickel alloy as the binder phase has obvious limitations in the above-mentioned complex environment. The binder phase is easy to soften at high temperature, resulting in insufficient red hardness of the material. More prominently, these traditional binder phases have poor chemical stability in corrosive media and are prone to preferential corrosion, causing the hard particles to fall off and greatly shortening the service life of the parts. Therefore, it is urgent to develop a new type of hard alloy system with excellent strength and toughness, high temperature stability and excellent corrosion resistance.

[0004] The FeCoCrNiMo 0.3 The new type of hard alloy with high-entropy alloy and TiC hard phase is just to solve this technical bottleneck. The material system uses multi-main-element high-entropy alloy as the binder phase, which has inherent high strength, good toughness and excellent corrosion resistance brought by Cr and Mo elements, significantly improving the ability of the matrix to resist chemical corrosion and mechanical wear. At the same time, the TiC hard phase provides extremely high hardness and thermal stability. The synergistic effect of the two makes the composite material maintain high wear resistance while effectively resisting the corrosion of corrosive media and high temperature environment, thereby providing a more superior performance and longer service life solution for parts operating in extreme conditions where strong wear and strong corrosion coexist. SUMMARY

[0005] To solve the obvious limitations of hard alloy in complex environments, especially the poor red hardness and insufficient corrosion resistance, the present application proposes a preparation method of high-entropy alloy binder phase hard alloy: FeCoCrNiMo 0.3 high-entropy alloy powder and TiC powder are mixed and sintered according to a specific ratio, and the respective characteristics of the two materials are used to improve the red hardness and corrosion resistance, and to develop a new type of hard alloy system with excellent strength and toughness, high temperature stability and excellent corrosion resistance.

[0006] To achieve the above object, the technical scheme of the present application is as follows.

[0007] S1, FeCoCrNiMo 0.3 The high-entropy alloy powder is refined by planetary ball milling to a particle size of 0.5-3 µm as a binder phase;

[0008] S2, the obtained binder phase is mixed with 1-5 µm TiC powder at a ratio of 35-48 wt%, and mechanical alloying is carried out under the conditions of a ball-to-powder ratio of 1:1 and a rotation speed of 300-400 rpm for 4-8 h to obtain a mixed powder;

[0009] S3, the mixed powder is placed in a graphite mold, heated to 900-1050 ℃ at a rate of 10 ℃ / min under vacuum-argon protective atmosphere, and held for 2 h, while an axial oscillation pressure of 65±5 MPa and a frequency of 50 Hz is applied for sintering, followed by furnace cooling to obtain a dense sintered compact;

[0010] S4, the dense sintered compact is sequentially subjected to annealing at 550-570 ℃ for 6 h, gas quenching solid solution at 1000-1100 ℃ for 30-60 min, and aging treatment at 550-600 ℃ for 1-3 h to obtain a high-hardness, high-toughness, corrosion-resistant hard alloy.

[0011] The beneficial effects of the present application are:

[0012] 1. In the technical scheme of the present application, Cr-containing high-entropy alloy is used as the hard alloy matrix material, and the characteristics of difficult motion of dislocations in hard alloy and the synergistic optimization of FCC and BCC dual-phase materials are utilized to improve the wear resistance, corrosion resistance and mechanical properties of the matrix material.

[0013] 2. In the technical scheme of the present application, hot-pressing oscillation sintering technology is adopted, which introduces dynamic oscillation pressure (±5 MPa cyclic pressure) during sintering to promote plastic deformation and grain boundary sliding of powder particles, thereby realizing close combination of particles at a lower temperature and in a shorter time. Unlike traditional hot-pressing sintering, the hot-pressing oscillation sintering technology optimizes particle arrangement through an oscillation field, reduces oxidation reaction and improves material stability. DETAILED DESCRIPTION

[0014] In order to make the object, technical scheme and advantages of the present application clearer and more apparent, the present application will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0015] Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application.

[0016] Example 1

[0017] A method for preparing a high-entropy alloy binder phase cemented carbide, comprising the following steps:

[0018] S1, raw material preparation and pretreatment

[0019] Take the high-entropy alloy powder with the composition FeCoCrNiMo 0.3 as the binder phase, with an initial particle size of 75-250 pm; first dry grind with a planetary ball mill to a particle size of 0.5-3 pm to obtain ultra-fine powder that is cold-hardened and surface-activated; at the same time, select TiC with an average particle size of 1-5 pm as the hard phase, and both are dried at 80°C for 2h before use.

[0020] S2, preparation of mixed powder

[0021] The above two powders are mixed according to the target mass ratio, with a TiC content of 35wt%, placed in a stainless steel ball mill jar, a ball-to-material ratio of 1:1, and mechanically alloyed at 350 rpm for 6h to form a mixed powder.

[0022] S3, hot pressing and oscillation sintering

[0023] The mixed powder is quickly loaded into a high-strength graphite mold and sent into a hot pressing and oscillation sintering furnace; the furnace chamber is first evacuated and then filled with argon to 5MPa; the temperature is raised to 1000°C at a rate of 100°C / h and held for 2h, and during the holding stage, an axial oscillation pressure of 65±5MPa is applied synchronously at a frequency of 50Hz; the material is cooled to room temperature with the furnace, and a crack-free, near-net-shape sintered body is obtained.

[0024] S4, heat treatment

[0025] The sintered body is subjected to three-step heat treatment to optimize its microstructure and overall performance.

[0026] Annealing treatment: place the sintered body in a heat treatment furnace and hold at 550°C for 6 hours, then cool with the furnace. This process aims to eliminate internal stress generated during sintering and homogenize the structure.

[0027] Solution treatment: the annealed sample is subjected to solution treatment at 1080°C for 60 minutes to fully dissolve the alloying elements into the matrix. After completion, the sample is quickly transferred to a gas quenching device and rapidly cooled to room temperature using high-speed argon gas to obtain a supersaturated solid solution.

[0028] Aging treatment: the sample after solution treatment is subjected to aging at 550°C for 2 hours, and after completion, air cooling or water quenching to room temperature.

[0029] Example 2

[0030] A high-entropy alloy binder phase cemented carbide preparation method, comprising the following steps:

[0031] S1, raw material preparation and pretreatment

[0032] The high-entropy alloy powder with a composition of FeCoCrNiMo 0.3 is used as the binder phase, with an initial particle size of 75-250 µm; it is first dry ground in a planetary ball mill to a particle size of 0.5-3 µm to obtain a cold-worked and surface-activated ultrafine powder; at the same time, TiC with an average particle size of 1-5 µm is selected as the hard phase, and the two are vacuum dried at 80°C for 2h before use.

[0033] S2, preparation of mixed powder

[0034] The above two powders are mixed according to the target mass ratio, with a TiC content of 48wt%, placed in a stainless steel ball mill jar, a ball-to-material ratio of 1:1, and mechanically alloyed at 350rpm for 6h to form a mixed powder.

[0035] S3, hot pressing and oscillation sintering

[0036] The mixed powder is quickly loaded into a high-strength graphite mold and sent into a hot pressing and oscillation sintering furnace; the furnace chamber is first evacuated and then filled with argon to 5MPa; the temperature is raised to 1000°C at a rate of 100°C / h and held for 2h, and during the holding stage, an axial oscillation pressure of 65±5MPa is applied synchronously, with a frequency of 50Hz; the material is cooled to room temperature with the furnace, and a crack-free, near-net-shape sintered body is obtained.

[0037] S4, heat treatment

[0038] The sintered body is subjected to three-step heat treatment to optimize its microstructure and overall performance.

[0039] Annealing treatment: the sintered body is placed in a heat treatment furnace and held at 550°C for 6 hours, then cooled with the furnace. This process aims to eliminate internal stress generated during sintering and homogenize the structure.

[0040] Solution treatment: the annealed sample is subjected to solution treatment at 1080°C for 60 minutes to fully dissolve the alloying elements into the matrix. After completion, the sample is quickly transferred to a gas quenching device and rapidly cooled to room temperature using high-speed argon to obtain a supersaturated solid solution.

[0041] Aging treatment: the sample after solution treatment is subjected to aging at 550°C for 2 hours, and after completion, it is air-cooled or water-quenched to room temperature.

[0042] Example 3

[0043] S1, raw material preparation and pretreatment

[0044] The high-entropy alloy powder with a composition of FeCoCrNiMo 0.3The high-entropy alloy powder is the binder phase, with an initial particle size of 75-250 pm; it is first dry-milled in a planetary ball mill to a particle size of 0.5-3 pm to obtain a cold-worked and surface-activated ultrafine powder; and TiC with an average particle size of 1-5 pm is selected as the hard phase, and the two are dried in a vacuum at 80°C for 2 h.

[0045] S2, Preparation of mixed powder

[0046] The two powders are mixed according to the target mass ratio, with a TiC content of 48wt%, placed in a stainless steel ball mill jar, a ball-to-material ratio of 1:1, and mechanically alloyed at 350 rpm for 6 h to form a mixed powder.

[0047] S3, Hot pressing and sintering

[0048] The mixed powder is quickly loaded into a high-strength graphite mold and sent to a hot pressing and sintering furnace; the furnace chamber is first evacuated and then filled with argon to 5 MPa; the temperature is raised to 1000°C at a rate of 100°C / h and held for 2 h, and a 65±5 MPa axial oscillatory pressure is applied simultaneously during the holding stage, with a frequency of 50 Hz; the material is cooled to room temperature with the furnace, and a crack-free, near-net-shape sintered body is obtained.

[0049] S4, Heat treatment

[0050] The sintered body is subjected to three-step heat treatment to optimize its microstructure and overall performance.

[0051] Annealing: The sintered body is placed in a heat treatment furnace and held at 550°C for 6 hours, then cooled with the furnace. This process aims to eliminate internal stress generated during sintering and homogenize the structure.

[0052] Solution treatment: The annealed sample is solution treated at 1100°C for 60 minutes to fully dissolve alloying elements into the matrix. After completion, the sample is quickly transferred to a gas quenching device and rapidly cooled to room temperature using high-speed argon gas to obtain a supersaturated solid solution.

[0053] Aging treatment: The sample after solution treatment is aged at 550°C for 2 hours, and after completion, it is air-cooled or water-quenched to room temperature.

[0054] Example 4

[0055] A method for preparing a high-entropy alloy binder phase cemented carbide, comprising the following steps:

[0056] S1, Preparation of raw materials and pretreatment

[0057] The composition is FeCoCrNiMo 0.3The high-entropy alloy powder is the binder phase, with an initial particle size of 75-250 pm; it is first dry-milled in a planetary ball mill to a particle size of 0.5-3 pm to obtain a cold-worked and surface-activated ultrafine powder; and TiC with an average particle size of 1-5 pm is selected as the hard phase, and the two are dried in a vacuum at 80°C for 2 h.

[0058] S2, Preparation of mixed powder

[0059] The two powders are mixed according to the target mass ratio, with a TiC content of 48wt%, placed in a stainless steel ball mill jar, a ball-to-material ratio of 1:1, and mechanically alloyed at 350 rpm for 6 h to form a mixed powder.

[0060] S3, Hot pressing and sintering

[0061] The mixed powder is quickly loaded into a high-strength graphite mold and sent to a hot pressing and sintering furnace; the furnace chamber is first evacuated and then filled with argon to 5 MPa; the temperature is raised to 1000°C at a rate of 100°C / h and held for 2 h, and a 65±5 MPa axial oscillatory pressure is applied simultaneously during the holding stage, with a frequency of 50 Hz; the material is cooled to room temperature with the furnace, and a crack-free, near-net-shape sintered body is obtained.

[0062] S4, Heat treatment

[0063] The sintered body is subjected to three-step heat treatment to optimize its microstructure and overall performance.

[0064] Annealing treatment: the sintered body is placed in a heat treatment furnace and held at 550°C for 6 hours, and then cooled with the furnace. This process aims to eliminate internal stress generated during sintering and homogenize the structure.

[0065] Solution treatment: the annealed sample is solution treated at 1000°C for 60 minutes to fully dissolve the alloying elements into the matrix. After completion, the sample is quickly transferred to a gas quenching device and rapidly cooled to room temperature using high-speed argon gas to obtain a supersaturated solid solution.

[0066] Aging treatment: the sample after solution treatment is aged at 550°C for 2 hours, and then air-cooled or water-quenched to room temperature.

[0067] Comparative Example 1

[0068] A method for preparing a high-entropy alloy binder phase cemented carbide, comprising the following steps:

[0069] S1, Preparation and pretreatment of raw materials

[0070] The composition of FeCoCrNiMo 0.3High-entropy alloy powder as binder phase, the initial particle size range is 75-250 pm. The powder is put into a powder mixer without ball milling treatment. TiC powder with an average particle size of 1-5 pm is selected as the hard phase, and the TiC powder content is 48wt.%.

[0071] S2, Preparation of mixed powder

[0072] The pretreated FeCoCrNiMo 0.3 High-entropy alloy powder and TiC powder in a predetermined ratio. The mixed powder is placed in a planetary ball mill for mechanical mixing. The powder mixing process parameters are: the rotation speed of the powder mixer is set to 350 rpm, and the powder mixing time is 6 hours.

[0073] S3, hot pressing and sintering

[0074] The mixed powder is loaded into a graphite mold and transferred to a hot pressing and sintering furnace. Vacuum is extracted and argon is filled as a protective atmosphere. Sintering is carried out according to the set sintering process: heating to 1000℃ at a rate of 10℃ / min, and holding at this temperature for 2 hours. During the holding period, an oscillating pressure of 65±5MPa is applied to improve the contact between powder particles, break up possible agglomerates, and thus significantly accelerate the densification process of the sintered body. After sintering is completed, the furnace is cooled to room temperature to obtain a dense sintered body.

[0075] S4, heat treatment

[0076] The sintered body is subjected to three-step heat treatment to optimize its microstructure and comprehensive performance.

[0077] Annealing treatment: the sintered body is placed in a heat treatment furnace and held at 550℃ for 6 hours, then cooled in the furnace. This process aims to eliminate internal stress generated during sintering and homogenize the structure.

[0078] Solution treatment: the annealed sample is solution treated at 1100℃ for 60 minutes to fully dissolve the alloying elements into the matrix. After completion, the sample is quickly transferred to a gas quenching device and rapidly cooled to room temperature using high-speed argon to obtain a supersaturated solid solution.

[0079] Aging treatment: the sample after solution treatment is aged at 550℃ for 2 hours, and then air-cooled or water-quenched to room temperature after completion.

[0080] Comparative Example 2

[0081] A method for preparing a high-entropy alloy binder phase cemented carbide, comprising the following steps:

[0082] S1, preparation and pretreatment of raw materials

[0083] The binder phase was pure cobalt powder with an initial particle size range of 1-5 pm. The powder was placed in a powder mixer without ball milling. The hard phase was TiC powder with an average particle size of 1-5 pm, and the TiC powder content was 48 wt.%.

[0084] S2, Preparation of mixed powder

[0085] The pre-processed cobalt powder and TiC powder were mixed in a predetermined ratio. The mixed powder was placed in a powder mixer for mechanical mixing. The mixing parameters were: the rotation speed was set to 350 rpm, and the mixing time was 6 hours.

[0086] S3, Hot-pressing oscillation sintering

[0087] The mixed powder was loaded into a graphite mold and transferred to a hot-pressing oscillation sintering furnace. Vacuum was drawn and argon was filled as a protective atmosphere. The sintering process was carried out according to the set parameters: the temperature was raised to 1000°C at a rate of 10°C / min, and the temperature was maintained for 2 hours. During the holding period, an oscillation pressure of 65±5 MPa was applied to improve the contact between the powder particles, break up possible agglomerates, and thus significantly accelerate the densification process of the sintered body. After sintering, the furnace was cooled to room temperature to obtain a dense sintered body.

[0088] S4, Heat treatment

[0089] The sintered body was subjected to three-step heat treatment to optimize its microstructure and overall performance.

[0090] Annealing treatment: the sintered body was placed in a heat treatment furnace and held at 550°C for 6 hours, and then cooled in the furnace. This process aims to eliminate internal stress generated during sintering and homogenize the structure.

[0091] Solution treatment: the annealed sample was subjected to solution treatment at 1100°C for 60 minutes to fully dissolve the alloying elements into the matrix. After completion, the sample was quickly transferred to a gas quenching device and rapidly cooled to room temperature using high-speed argon to obtain a supersaturated solid solution.

[0092] Aging treatment: the sample after solution treatment was subjected to aging at 550°C for 2 hours, and then air-cooled or water-quenched to room temperature after completion.

[0093] Test 1, Mechanical property test

[0094] Test item Hardness (HRC) Bending strength (MPa) Impact toughness (J) Example 1 60 3804 28 Example 2 62 3552 24 Example 3 63 3189 25 Example 4 61 3362 26 Comparative Example 1 62 2573 19 Comparative Example 2 58 3215 28

[0095] The above test results show that the present application can significantly improve the mechanical properties of the sintered body by using "FeCoCrNiMo 0.3The synergistic effect among the three, high-entropy alloy binder phase, powder refinement and mechanical alloying, and oscillatory pressure sintering and specific heat treatment, realizes the best balance of hardness, strength and toughness of the cemented carbide.

[0096] In particular:

[0097] Comparative Example 2 (pure cobalt binder phase) has significantly lower hardness (HRC 58 vs. 62) compared to Example 2 (high-entropy alloy binder phase) under the same process, proving that the high-entropy alloy binder phase makes an independent and key contribution to the hardness improvement through multi-principal element solid solution strengthening effect.

[0098] Comparative Example 1 (without ball milling pretreatment) has a sharp decrease in bending strength (2573 MPa vs. 3552 MPa) and impact toughness (19 J vs. 24 J) compared to Example 2 (complete process) under the same composition, proving that the "refinement pretreatment" step is essential for eliminating defects in the original powder, realizing densification sintering, and thus obtaining high strength and toughness, and this step cannot be omitted.

[0099] The comparison of Examples 2, 3 and 4 shows that the performance fluctuates when the solid solution temperature changes between 1000℃ and 1100℃, proving that the specific heat treatment system of the present application is the key to regulating the final performance, and the parameter range is the result of careful design and optimization.

[0100] In this specification, expressions such as "one embodiment", "an example", or "a specific example" refer to at least one embodiment or example of the present application.

[0101] It should be noted that the illustrative expressions of these terms do not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0102] The above description of specific embodiments of the present application is only illustrative and not limiting. Any modifications, equivalent replacements or improvements made by any person skilled in the art within the scope defined by the claims of the present application shall be considered to fall within the protection scope of the present application.

Claims

1. A method of producing a high-entropy alloy binder phase cemented carbide, characterized by, The method comprises the following steps: (a) FeCoCrNiMo 0.3 High-entropy alloy powder was refined by planetary ball milling to a particle size of 0.5-3 pm as a binder phase; (b) mixing the adhesive phase obtained in step (a) with 1-5 µm TiC powder at a ratio of 35-48 wt%, and performing mechanical alloying under the conditions of a ball-to-powder ratio of 1:1 and a rotation speed of 300-400 rpm for 4-8 h to obtain a mixed powder; (c) placing the mixed powder in a graphite mold, and performing sintering under a vacuum-argon protective atmosphere at a temperature rising rate of 10 ℃ / min to 900-1050 ℃ and maintaining for 2 h while applying an axial oscillation pressure of 65±5 MPa and a frequency of 50 Hz, and then cooling in the furnace to obtain a dense sintered compact; (d) sequentially performing annealing, solid solution and aging treatment on the dense sintered compact; wherein the annealing is performed at 550-570 ℃ for 6 h; the solid solution treatment is performed at 1000-1100 ℃ for 30-60 min and then air quenched; and the aging treatment is performed at 550-600 ℃ for 1-3 h.

2. The method of claim 1, wherein: The TiC content is 48 wt%.

3. The method according to claim 1 or 2, characterized in that: The solid solution treatment temperature is 1000-1080 ℃.

4. The method of claim 1, wherein: The oscillation pressure amplitude is ±2 MPa.

5. The method of claim 1, wherein: The aging treatment is performed at 550 ℃ for 2 h and then air cooled.

6. A high-entropy alloy binder phase cemented carbide, characterized by: The method is prepared by the method in any one of claims 1-5.

7. The high-entropy alloy binder phase cemented carbolite according to claim 6, characterized in that: The hardness is HRC 60-63, the bending strength is 3180-3800 MPa, and the impact toughness is 24-28 J.