A high-entropy alloy binder phase diamond composite material and a preparation method thereof

Abstract

The application discloses a novel high-entropy alloy binder phase diamond composite material with excellent wear resistance and a preparation method thereof. The composite material comprises 85-90 vol.% high-entropy alloy binder phase powder and 15-10 vol.% bare diamond powder. The composite material is prepared by weighing the required high-entropy alloy binder phase and bare diamond powder according to the configuration proportion, mixing by using a three-dimensional mixer, and rapidly hot-pressing sintering through pre-pressing deformation. The process has the advantages of simple flow, short production cycle, low production cost and no dangerous operation, and the prepared metal matrix composite material has the bending strength comparable to that of other binder phase composite materials and excellent wear resistance.

Description

Technical Field

[0001] The present invention relates to a metal-based diamond composite material, in particular to a high-entropy alloy binder phase diamond composite material and a preparation method thereof, belonging to the field of composite material preparation. Background Art

[0002] Traditional synthetic diamond composites are widely used in fields such as thermal conductivity, abrasive tools, diamond grinding wheels, and machining. Traditional diamond composites have a low diamond content of approximately 10% to 20%. Due to the low diamond content, the properties of the binder phase, the diamond retention capacity, and the interfacial bonding strength between the binder phase matrix and the diamond are key factors affecting the performance of diamond composites. Sintering is a common method for preparing diamond composites, and the sintering temperature is usually above 1000°C. However, diamond has poor thermal stability and is prone to graphitization. If the diamond in the composite material graphitizes, it will affect the bonding between the diamond and the binder phase matrix, and will also reduce the hardness and wear resistance of the diamond itself, leading to failure of the composite material. At the same time, the wettability between the diamond and the metal binder phase is relatively poor, making it difficult to form a strong interfacial bond, making it easy for diamond tools to cause abrasive spalling during use. In order to solve the above problems, coated diamond is usually used. For example, in the article "Effect of diffusion barrier and interfacial strengthening on the interface behavior between high entropy alloy and diamond" published in 2021, they introduced Ti-coated diamond and Fe 25 Co 25 Cr 25 Ni 25It was found that a TiC layer was generated in situ at the interface between diamond and the substrate, which played the role of diffusion barrier and strengthening layer, improved interface bonding, and inhibited diamond graphitization. The flexural strength and friction coefficient of the material were 925.5MPa and 0.15, respectively. The mechanical properties and wear resistance of the material were relatively good. In the article "Effect of Ti / NiCoating of Diamond Particles on Microstructure and Properties of High-EntropyAlloy / Diamond Composites" published in 2019, they introduced Ti / Ni coated diamond, and the flexural strength and friction coefficient of the prepared diamond composite material were approximately 750MPa and 0.05, respectively. In the article "Enhancedproperties of a novel medium-entropy alloy base diamond composite byintroducing coherent L12phase at interface" published in 2024, they used a medium-entropy alloy MEA:Co 34.07 Ni 33.94 Cr 13.57 Ti 7.82 Al 5.17 M 5.43 At% (M=Mo / W / Ta / Zr / Hf) and bare diamond powder were synthesized through hot pressing and sintering. An intermediate layer composed of L12 phase and chromium carbide was formed in situ between the diamond and the metal matrix. This intermediate layer improved the bonding between the diamond and the metal matrix and alleviated the graphitization of the diamond under service conditions. The average friction coefficient of the diamond composite was 0.1310 and the friction loss was low. Wear ratio experiments also found that the wear ratio of the diamond composite with a medium entropy alloy matrix was 706, indicating that the material has good wear resistance. This research shows that developing new binder phase alloy systems to improve the interfacial bonding between diamond and the matrix, thereby improving the wear resistance of composite materials, is currently a promising direction. Summary of the Invention

[0003] The present invention is guided by the development of high entropy alloy bonded phase diamond composite materials with excellent wear resistance after sintering at about 1000-1100 ° C. Co x Ni y Ti z Zr 1-x-y-zHigh-entropy alloy powder. By adjusting the composite material composition, sintering temperature, and sintering time, the designed composite material has excellent wear resistance.

[0004] The technical solution of the present invention is:

[0005] The present invention discloses a novel high-entropy alloy binder phase diamond composite material with excellent wear resistance, which consists of a high-entropy alloy binder phase and diamond, wherein the high-entropy alloy binder phase content is 80-90 vol.%, and the diamond content is 20-10 vol.%;

[0006] The element components and their atomic percentages of the high entropy alloy are: Co is 20-30%, Ni is 20-30%, Ti is 20-30%, and Zr is the balance;

[0007] The diamond has a particle size of 170-200 meshes.

[0008] Preferably, the diamond comprises bare diamond particles having a complete crystal form.

[0009] As a further preference, the model of the diamond is DSD80.

[0010] Preferably, a novel high entropy alloy binder phase diamond composite material is provided, wherein in the high entropy alloy binder phase, the ratio of Co:Ni:Ti:Zr is 1:1:1:1, calculated by mole percentage.

[0011] As a preferred embodiment, the novel high-entropy alloy binder phase diamond composite material with excellent wear resistance has a high-entropy alloy binder phase content of 85-90 vol.%, and a diamond content of 15-10 vol.%. As a further preferred embodiment, the high-entropy alloy binder phase content is 87.5 vol.%, and the diamond content is 12.5 vol.%.

[0012] The preparation method of the novel high entropy alloy binder phase diamond composite material of the present invention comprises: weighing required high entropy alloy binder phase powder and bare diamond powder according to a configuration ratio, mixing them, performing pre-compression deformation, and then hot pressing and sintering to obtain the composite material; the hot pressing and sintering temperature is 1010-1100°C.

[0013] As a preferred solution, the high entropy alloy binder phase and bare diamond powder are mixed using a three-dimensional mixer.

[0014] As a preferred solution, the hot pressing sintering temperature is 1040-1060° C., the sintering time is about 10-20 minutes, and the sintering pressure is about 30-50 MPa.

[0015] The preparation method of the novel high entropy alloy binder phase diamond composite material with excellent wear resistance comprises the following steps:

[0016] (1) Ingredients: Calculate the required content of metals Co, Ni, Ti, and Zr with a purity of 99.9% according to atomic percentage; and weigh the required diamond powder.

[0017] (2) Powdering: The high entropy alloy binder phase powder is prepared by ultrasonic atomization. This method can produce large quantities of powder with high sphericity. The prepared powder has good fluidity and formability, which is conducive to improving the uniformity of the composite material performance.

[0018] (3) Powder mixing: The high entropy alloy binder phase powder and diamond powder weighed according to the configuration ratio are mixed in a three-dimensional mixer for 24 hours to achieve uniform mixing of the binder phase and bare diamond powder. This method avoids the safety accidents and impurities that may be caused by the mechanical ball milling method.

[0019] (4) Sintering: The specific sintering process is to first evacuate to 5~50Pa, heat the temperature from room temperature to 715~800℃ at a heating rate of 80~120℃ / min, keep warm for 1~3min, and pressurize to a forming pressure of 30~50MPa; then heat the temperature to a sintering temperature of 1010~1100℃ at a heating rate of 80~130℃ / min, and keep warm for 8~24min.

[0020] The diamond powder includes bare diamond powder.

[0021] The high-entropy alloy bond phase diamond composite material designed and prepared in the present invention has a flexural strength of not less than 512.26 MPa. After a friction and wear test, the wear amount of the material does not exceed 0.0076 g, and the friction coefficient of the material does not exceed 0.5 during the friction time of 600s to 1800s.

[0022] By regulating the sintering temperature and sintering time, the flexural strength of the high-entropy alloy bond phase diamond composite material is not less than 642.58 MPa. After friction and wear tests, the wear amount of the material is 0.0013 g. During the friction time of 600s to 1800s, the friction coefficient of the material is around 0.05, and the wear ratio of the material is 843.

[0023] Compared with the existing technology, the present invention has the following advantages:

[0024] 1. The present invention adopts new Co x Ni y Ti z Zr 1-x-y-zHigh-entropy alloys, as the metallic binder phase of diamond composites, have introduced a new binder phase system into the field of diamond composites. The binder phase elements Co and Ni have a good lattice match with diamond, while Ti and Zr are carbide-forming elements.

[0025] 2. The present invention uses a three-dimensional powder mixer to mix powders and a rapid hot-pressing sintering process to produce a high-entropy alloy binder-phase diamond composite. This method is carried out entirely under atmospheric pressure, has a simple process flow, a short production cycle, and low production costs, making it suitable for large-scale production.

[0026] 3. Co of the present invention x Ni y Ti z Zr 1-x-y-z -Diamond composite materials have excellent wear resistance and maintain bending strength comparable to other alloy composite materials.

[0027] 4. The present invention provides a sintering parameter of a new high entropy alloy binder phase diamond composite material with excellent wear resistance. By adjusting the sintering temperature and sintering time during sintering, a diamond composite material with better wear resistance can be prepared. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 For comparative example 1 Co x Ni y Ti z Zr 1-x-y-z The high entropy alloy binder phase and bare diamond particles were sintered at 1000℃; and the surface microstructure of the composite material was observed after being kept at 1000℃ for 10 min.

[0029] Figure 2 For comparative example 2 Co x Ni y Ti z Zr 1-x-y-z The high entropy alloy binder phase and bare diamond particles were sintered at 1000℃; and the surface microstructure of the composite material was observed after being kept at 1000℃ for 20 minutes.

[0030] Figure 3 Example 1 Co x Ni y Ti z Zr 1-x-y-z The high entropy alloy binder phase and bare diamond particles were sintered at 1050℃; and the surface microstructure of the composite material was observed after being kept at 1050℃ for 10 min.

[0031] Figure 4 This is the surface microstructure morphology of the diamond composite material of Comparative Example 1 after friction and wear testing.

[0032] Figure 5 The surface microstructure of the diamond composite material of Comparative Example 2 after the friction and wear test.

[0033] Figure 6 The surface microstructure of the diamond composite material of Example 1 after the friction and wear test.

[0034] Figure 7 The energy spectrum image of the interface of the diamond composite material of Comparative Example 1.

[0035] Figure 8 The energy spectrum image of the interface of the diamond composite material of Comparative Example 2.

[0036] Figure 9 The energy spectrum image of the interface of the diamond composite material of Example 1.

[0037] Figure 10 The test force-friction force-friction coefficient curve of the diamond composite materials of Comparative Examples 1, 2 and Example 1 after the friction and wear test.

[0038] Figure 11 The transverse rupture strength of the diamond composite materials of Comparative Examples 1, 2 and Example 1.

[0039] From Figure 1 , 2 and 3, it can be seen that there is an obvious phenomenon of diamond particle falling off in Comparative Examples 1 and 2, and the diamond crystal form in Example 1 is more complete, the surface is smoother, and the ablation trace is not obvious. It is shown that the sintering temperature is increased, and the combination between the diamond and the binder phase is more closely.

[0040] From Figure 4 , 5 and 6, it can be seen that the sample surfaces of Comparative Examples 1 and 2 after the friction and wear test leave more obvious traces of Si3N4 ball friction, and the sample surface of Example 1 is smoother.

[0041] From Figure 7 , 8 and 9, it can be seen that there is enrichment of Zr element at the interface between the diamond and the binder phase matrix in the samples of Comparative Example 2 and Example 1, which shows that there may be an interface reaction between the binder phase and the diamond, and the interface bonding strength is higher.

[0042] From Figure 10It can be seen that within 600~1800s of Si3N4 ball friction, the friction coefficients of the three samples tend to be stable. The friction coefficients of comparative examples 1 and 2 are similar, about 0.4, while the friction coefficient of embodiment 1 is relatively low, about 0.05. The wear resistance of embodiment 1 is better, indicating that the wear resistance of the material can be improved by adjusting the sintering temperature and sintering time.

[0043] from Figure 11 It can be seen that with the increase of sintering time and sintering temperature, the transverse rupture strength of the sample gradually increases, indicating that the bonding between diamond and the bonding phase may be better, and the sample in the present invention has a transverse rupture strength comparable to that of other materials, and has good comprehensive performance. DETAILED DESCRIPTION

[0044] The present invention is described in detail below with reference to specific examples.

[0045] In Example 1, the wear ratio is tested according to JB / T 3235-2023.

[0046] Comparative Example 1

[0047] 1. Material preparation:

[0048] (1) Prepare Co x Ni y Ti z Zr 1-x-y-z High entropy alloy powder: Co, Ni, Ti and Zr metal raw materials with a purity of 99.9% are made by ultrasonic atomization to form a high entropy alloy powder with a composition of Co x Ni y Ti z Zr 1-x-y-z (at%, x=25, y=25, z=25) alloy powder.

[0049] (2) Prepare diamond powder: Select diamonds with a particle size range of 170-200 mesh and model DSD80. Diamond powder is all bare diamond.

[0050] (3) Powder mixing: Use a three-dimensional powder mixer to mix Co x Ni y Ti z Zr 1-x-y-z The alloy powder and diamond powder were mixed for 24 hours. The diamond content was 12.5 vol.%, Co x Ni y Ti z Zr 1-x-y-z The alloy powder content is 87.5 vol.%.

[0051] 2. Preparation of CoNiTiZr-based diamond composite materials:

[0052] The above Co x Ni y Ti z Zr 1-x-y-z The alloy powder-diamond mixed powder is loaded into a graphite mold and pre-pressed before rapid hot pressing and sintering. Vacuum is applied and the temperature is raised from room temperature to 800°C at a rate of 85°C / min. After a 2-minute hold, the pressure is simultaneously increased to a forming pressure of 50 MPa. The temperature is then raised from 800°C to the sintering temperature of 1000°C at a rate of 100°C / min, and held at the sintering temperature for 10 minutes.

[0053] Comparative Example 2

[0054] 1. Material preparation: The material preparation of Comparative Example 2 is the same as that of Comparative Example 1.

[0055] 2. Preparation of high entropy alloy binder phase diamond composite materials:

[0056] The above Co x Ni y Ti z Zr 1-x-y-z The alloy powder-diamond mixed powder is loaded into a graphite mold and, after pre-pressing, rapidly hot-pressed and sintered. Vacuum is applied and the temperature is raised from room temperature to 800°C at a rate of 85°C / min. After a 2-minute hold, the pressure is simultaneously increased to a forming pressure of 50 MPa. The temperature is then raised from 800°C to the sintering temperature of 1000°C at a rate of 100°C / min, and held at the sintering temperature for 20 minutes.

[0057] Example 1

[0058] 1. Material preparation: The material preparation of Example 1 is consistent with that of Comparative Examples 1 and 2.

[0059] 2. Preparation of high entropy alloy diamond composite materials:

[0060] The above Co x Ni y Ti z Zr 1-x-y-z The alloy powder-diamond mixed powder is loaded into a graphite mold and pre-pressed before rapid hot pressing and sintering. The mold is vacuumed and heated from room temperature to 800°C at a rate of 85°C / min. After a 2-minute hold, the pressure is simultaneously increased to 50 MPa. The mold is then heated from 800°C to a sintering temperature of 1050°C at a rate of 125°C / min, and held at the sintering temperature for 10 minutes.

[0061]

[0062] As shown in Table 1, after rapid hot pressing and sintering at 1050°C for 10 minutes and a 30-minute friction and wear test, the composite material of Example 1 showed less wear than the Si3N4 ball, at 0.0013g, while the Si3N4 ball showed twice the wear of the composite material, at 0.0026g. The wear of Comparative Examples 1 and 2 was higher than that of the Si3N4 ball, at 0.0049g and 0.0076g, respectively. This indicates that increasing the sintering temperature helps promote the bonding of diamond to the binder phase matrix, further improving the flexural strength and wear resistance of the composite material.

[0063]

[0064] As shown in Table 2, the wear ratio of Example 1 is 843 after being kept at 1050℃ for 10 minutes under the conditions of rapid hot pressing sintering according to JB / T 3235-2023. Compared with the composite materials made of other bonding phases, its wear ratio is relatively high, indicating that under this sintering condition, Co x Ni y Ti z Zr 1-x-y-z The composite material formed by the alloy binder phase and diamond has good wear resistance and bending strength.

Claims

1. A high entropy alloy binder phase diamond composite material, characterized by: It consists of two parts: high entropy alloy binder phase and diamond, wherein the high entropy alloy binder phase content is 80-90vol.%, and the diamond content is 10-20vol.%; The element components and their atomic percentages of the high entropy alloy are: Co is 20-30%, Ni is 20-30%, Ti is 20-30%, and Zr is the balance; The diamond has a particle size of 170-200 mesh; The high-entropy alloy binder phase diamond composite material is obtained by weighing required high-entropy alloy powder and bare diamond powder according to a configuration ratio, mixing them, performing pre-compression deformation, and then hot pressing and sintering; the hot pressing and sintering temperature is 1010-1100° C., the sintering time is 10-20 minutes, and the sintering pressure is 30-50 MPa.

2. The high entropy alloy binder phase diamond composite material according to claim 1, characterized in that: In the high entropy alloy binder phase, Co:Ni:Ti:Zr=1:1:1:1, calculated in molar percentage.

3. The high entropy alloy binder phase diamond composite material according to claim 1, characterized in that: The diamond includes bare diamond particles having a complete crystal form.

4. The high entropy alloy binder phase diamond composite material according to claim 1, characterized in that: The model of the diamond is DSD80.

5. The high entropy alloy binder phase diamond composite material according to claim 1, characterized in that: The content of high entropy alloy binder phase is 85~90vol.%, and the content of diamond is 10-15vol.%.

6. The high entropy alloy binder phase diamond composite material according to claim 5, characterized in that: The content of high entropy alloy binder phase is 87.5 vol.%, and the content of diamond is 12.5 vol.%.

7. A method for preparing a high entropy alloy binder phase diamond composite material according to any one of claims 1 to 6, characterized in that: The required high entropy alloy powder and bare diamond powder are weighed and mixed according to the configuration ratio, and then pre-pressed and deformed and then hot-pressed to obtain the powder; the hot-pressing sintering temperature is 1010-1100° C., the sintering time is 10-20 minutes, and the sintering pressure is 30-50 MPa.

8. The method for preparing a high entropy alloy binder phase diamond composite material according to claim 7, characterized in that: First, evacuate to 5~50Pa, heat up from room temperature to 715~800℃ at a heating rate of 80~120℃ / min, keep warm for 1~3min, and pressurize to forming pressure 30~50MPa; then heat up to sintering temperature 1010~1100℃ at a heating rate of 80~130℃ / min, and keep warm for 10~20min.

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