Laminated structure graphene / CoCrNi multi-principal element alloy wear-resistant composite material and preparation method thereof
By ball milling spherical CoCrNi multi-principal alloy powder into flakes, and then mixing it with graphene powder followed by low-energy ball milling and spark plasma sintering, the problem of graphene's difficulty in dispersing in CoCrNi multi-principal alloy composites was solved, thereby improving wear resistance and preparation efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- RES & DEV INST OF NORTHWESTERN POLYTECHNICAL UNIV IN SHENZHEN
- Filing Date
- 2026-01-27
- Publication Date
- 2026-05-01
AI Technical Summary
In existing technologies, graphene is difficult to disperse uniformly in CoCrNi multi-principal-element alloy composites, resulting in poor wear resistance. Furthermore, existing dispersion methods are time-consuming and labor-intensive, making it difficult to meet the needs of aerospace and other fields.
By ball milling spherical CoCrNi multi-principal alloy powder into flakes, mixing it with graphene powder, and then ball milling it at low energy, a stacked structure is formed by spark plasma sintering, which promotes the uniform dispersion of graphene on the surface of the CoCrNi multi-principal alloy matrix.
The wear resistance of CoCrNi multi-principal alloy was significantly improved, the agglomeration of graphene was reduced, the preparation efficiency was improved, and a stacked structure with two phases of FCC solid solution phase and Cr7C3 carbide phase was formed.
Smart Images
Figure CN121945748A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of graphene / CoCrNi multi-principal-element alloy composite materials and their preparation technology, specifically relating to a multilayered graphene / CoCrNi multi-principal-element alloy wear-resistant composite material and its preparation method. Background Technology
[0002] Compared to traditional alloys, multi-principal element alloys (initially also known as multi-component alloys, synthetic complex alloys, and complex enriched alloys) exhibit significant disorder due to the near-equal or near-equal atomic ratios of their principal elements, which contribute substantially to their composition. The simple solid solution structure of multi-principal element alloys ensures good plasticity and low-temperature toughness, while lattice distortion effects endow them with high strength and hardness. Furthermore, the slow diffusion effect provides excellent structural stability, and the complex passivation layer formed by multiple principal elements further guarantees excellent corrosion resistance. The synergistic effect of these unique properties enables multi-principal element alloys to meet the requirements of many harsh working environments, thus attracting widespread attention in key fields such as aerospace, shipbuilding, nuclear energy, and defense.
[0003] The simple solid solution structures of multi-principal element alloys mainly include face-centered cubic (FCC), body-centered cubic (BCC), and hexagonal close-packed (HCP) structures. CoCrNi multi-principal element alloys are typical single-phase FCC structure multi-principal element alloys, and their wear resistance needs improvement. To address the poor wear resistance of CoCrNi multi-principal element alloys, the introduction of graphene is considered. Graphene's unique two-dimensional planar structure not only facilitates the structural control and functional design of metal matrix composites but also possesses excellent thermal conductivity, electrical conductivity, and strength, making it a reinforcing phase material with significant potential for wear resistance. Studies have shown that graphene is beneficial for improving the wear resistance of metal matrix composites. Therefore, as an ideal reinforcing phase, graphene plays a crucial role in improving wear resistance. However, graphene tends to aggregate at the grain boundaries of the metal matrix during composite material preparation or deformation, which greatly reduces its wear-resistant effect. Existing dispersion methods are difficult to implement quickly and efficiently, and are mostly used in liquid environments. Dispersion involves processes such as filtration and drying, which are time-consuming, labor-intensive, and extremely cumbersome. Therefore, achieving efficient and rapid uniform dispersion of graphene remains a bottleneck hindering the development of related fields. Summary of the Invention
[0004] To address the problems existing in the prior art, the present invention aims to provide a multilayered graphene / CoCrNi multi-principal alloy wear-resistant composite material and its preparation method. The present invention can effectively reduce the agglomeration of graphene and significantly improve the wear resistance of CoCrNi multi-principal alloy.
[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a multilayered graphene / CoCrNi multi-principal-element alloy wear-resistant composite material includes the following steps: Spherical CoCrNi multi-principal-element alloy powder was processed into flake-shaped CoCrNi multi-principal-element alloy powder by ball milling. Graphene powder was mixed with sheet-like CoCrNi multi-principal alloy powder and ball-milled to allow the sheet-like CoCrNi multi-principal alloy powder to carry graphene powder, thus obtaining graphene / CoCrNi multi-principal alloy composite powder. The graphene / CoCrNi multi-principal-element alloy composite powder was densified by spark plasma sintering to obtain the layered graphene / CoCrNi multi-principal-element alloy wear-resistant composite material.
[0006] Preferably, in a protective atmosphere, spherical CoCrNi multi-principal element alloy powder is processed into flake-shaped CoCrNi multi-principal element alloy powder by ball milling. The ball milling balls are stainless steel balls with a diameter of 8~10 mm, the ball-to-material ratio is (8~10):1, the ball milling speed is 220~240 rpm, the ball milling process adopts intermittent ball milling, the effective ball milling time is 4~6 h, the ball milling running time is 19~21 min, and the ball milling pause time is 9~11 min.
[0007] Preferably, the preparation method of the present invention further includes the following process: The spherical CoCrNi multi-principal component alloy powder was vacuum dried to remove moisture, and then the vacuum-dried spherical CoCrNi multi-principal component alloy powder was processed into flake CoCrNi multi-principal component alloy powder by ball milling.
[0008] Preferably, graphene powder and sheet-like CoCrNi multi-principal-element alloy powder are mixed at a mass ratio of 0.01-0.03.
[0009] Preferably, in a protective atmosphere, graphene powder is mixed with flake-shaped CoCrNi multi-principal-element alloy powder and ball-milled. During ball milling, stainless steel balls with a diameter of 8-10 mm are used, the ball-to-material ratio is (3-5):1, and the ball milling speed is 90-150 rpm. The ball milling process is intermittent, with an effective ball milling time of 1-2 hours, a ball milling running time of 19-21 minutes, and a ball milling pause time of 9-11 minutes.
[0010] Preferably, the protective atmosphere is argon.
[0011] Preferably, the preparation method of the present invention further includes the following process: Graphene powder was vacuum dried to remove moisture. The vacuum-dried graphene powder was then mixed with sheet-like CoCrNi multi-principal-element alloy powder and ball-milled.
[0012] Preferably, when densifying the graphene / CoCrNi multi-principal-element alloy composite powder by spark plasma sintering: the treatment environment is a vacuum environment, the heating rate is 100~150 ℃ / min, the sintering temperature is 900~1000℃, the sintering pressure is 30~40 MPa, the holding time is 20~30 min, and the cooling rate is 150~200 ℃ / min.
[0013] Preferably, the spherical CoCrNi multi-principal-element alloy powder has a particle size of 15~45 μm and a purity of not less than 99.95 wt.%.
[0014] The present invention also provides a multilayered graphene / CoCrNi multi-principal-element alloy wear-resistant composite material, which is prepared by the above-described preparation method of the present invention.
[0015] The present invention has the following beneficial effects: This invention processes spherical CoCrNi multi-principal alloy particles through ball milling to obtain sheet-like CoCrNi multi-principal alloy powder. Using this sheet-like CoCrNi multi-principal alloy powder as a carrier particle, subsequent mixing of graphene powder with the sheet-like CoCrNi multi-principal alloy powder and ball milling allows the sheet-like CoCrNi multi-principal alloy powder to carry the graphene. The sheet-like CoCrNi multi-principal alloy powder not only has a larger specific surface area but also typically exhibits spontaneous stacking behavior with parallel orientation under gravity. On one hand, the large specific surface area of the sheet-like CoCrNi multi-principal alloy powder is beneficial for the adhesion of two-dimensional planar graphene, reducing the intrinsic agglomeration behavior of graphene. On the other hand, the sheet-like CoCrNi multi-principal alloy powder has the characteristic of spontaneous parallel stacking orientation. By densifying the graphene-carrying sheet-like CoCrNi multi-principal alloy powder through spark plasma sintering, a self-assembled layered structure (i.e., the layered graphene / CoCrNi multi-principal alloy wear-resistant composite material of this invention) is finally obtained. This invention increases the active interface area between graphene and CoCrNi multi-principal alloy by changing the shape of the original powder, thereby promoting the nucleation of the in-situ precipitated phase and increasing the volume fraction of the in-situ precipitated phase. Based on this, graphene is uniformly dispersed on the surface of sheet-like CoCrNi multi-principal alloy matrix powder using a ball milling method to prepare a layered graphene / CoCrNi multi-principal alloy wear-resistant composite material. The microstructure of the layered graphene / CoCrNi multi-principal alloy wear-resistant composite material prepared by this method consists of an FCC solid solution phase and in-situ reacted Cr7C3 carbide phases. Compared with existing conventional graphene / CoCrNi multi-principal alloy wear-resistant composite materials, the preparation method of this invention can effectively reduce graphene agglomeration and significantly improve preparation efficiency. Attached Figure Description
[0016] Figure 1 The image shows the microstructure of the 1.0 wt.% multi-principal-element alloy wear-resistant composite material of graphene / CoCrNi with a stacked structure prepared in Example 1 of this invention, as shown in the SEM image.
[0017] Figure 2 The image shows the microstructure of the 1.5 wt.% multi-principal-element alloy wear-resistant composite material of graphene / CoCrNi with a stacked structure prepared in Example 2 of this invention, as shown in the SEM image.
[0018] Figure 3(a) is a schematic diagram of the structure of the 3.0 wt.% stacked graphene / CoCrNi multi-principal-element alloy wear-resistant composite material prepared in Example 3 of the present invention; Figure 3(b) is a SEM image of the in-plane orientation microstructure of the 3.0 wt.% multi-principal-element alloy wear-resistant composite material of stacked graphene / CoCrNi prepared in Example 3 of the present invention. Figure 3(c) is a SEM image of the cross-sectional orientation of the 3.0 wt.% multi-principal-element alloy wear-resistant composite material of graphene / CoCrNi with stacked structure prepared in Example 3 of the present invention.
[0019] Figure 4(a) is a schematic diagram of the 3.0 wt.% multi-principal-element alloy wear-resistant composite material of stacked graphene / CoCrNi prepared in Comparative Example 1 of the present invention; Figure 4(b) is a SEM image of the microstructure of the 3.0 wt.% multi-principal-element alloy wear-resistant composite material of graphene / CoCrNi with stacked structure prepared in Comparative Example 1 of the present invention.
[0020] Figure 5 The XRD patterns of the 3.0 wt.% multilayered graphene / CoCrNi multi-principal alloy wear-resistant composite material prepared in Example 3 of this invention, the graphene / CoCrNi multi-principal alloy wear-resistant composite material prepared in Comparative Example 1, and the CoCrNi multi-principal alloy prepared in Comparative Example 2 are shown.
[0021] Figure 6 This diagram illustrates the wear rate results of the multilayered graphene / CoCrNi multi-principal alloy wear-resistant composite materials prepared in Examples 1 to 3 of this invention, as well as the graphene / CoCrNi multi-principal alloy wear-resistant composite material prepared in Comparative Example 1 and the CoCrNi multi-principal alloy prepared in Comparative Example 2. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0023] This invention provides a layered graphene / CoCrNi multi-principal alloy wear-resistant composite material. The microstructure of this composite material consists of two phases: an FCC solid solution phase and Cr7C3 carbides generated by in-situ reaction. In this invention's layered graphene / CoCrNi multi-principal alloy wear-resistant composite material, the mass ratio of CoCrNi multi-principal alloy powder to graphene is 1:(0.01~0.03).
[0024] Another object of the present invention is to provide a method for preparing the aforementioned multilayered graphene / CoCrNi multi-principal-element alloy wear-resistant composite material, the preparation method being specifically implemented according to the following steps: Step 1: Preparation of flake-shaped CoCrNi multi-principal alloy powder: Spherical CoCrNi multi-principal alloy powder with a particle size of 15-45 μm was dried and then ball-milled. Specifically, the spherical CoCrNi multi-principal alloy powder was placed in a vacuum drying oven and dried at 200℃ for 24 h. After drying, the corresponding spherical CoCrNi multi-principal alloy powder was transferred to a glove box and sealed in a ball mill jar under a protective atmosphere (argon atmosphere). The ball mill jar was then removed from the glove box and fixed on an omnidirectional planetary ball mill for ball milling to obtain flake-shaped CoCrNi multi-principal alloy powder. A 1 L stainless steel vacuum ball mill jar was selected, and stainless steel balls with a diameter of 8-10 mm were used. The ball-to-powder ratio was set to (8-10):1. The ball milling was conducted intermittently at a speed of 220–240 rpm. The effective milling time was 1–2 hours, with a running time of 19–21 minutes and a rest time of 9–11 minutes. After milling, the milling jar was removed and transferred to a glove box. The flake-shaped CoCrNi multi-principal element alloy powder was removed and packaged under an argon atmosphere for use in step 2. In the following examples and comparative examples, the purity of the spherical CoCrNi multi-principal element alloy powder raw material was not less than 99.95 wt.%.
[0025] Step 2: Prepare multi-principal element alloy powder and graphene powder, and make them in a mass ratio of 1: x ( x Weigh out sheet-like CoCrNi multi-principal element alloy powder and graphene powder according to a ratio of 0.01~0.03. The specific method includes: weighing out the sheet-like CoCrNi multi-principal element alloy powder and graphene powder according to a predetermined material mass fraction. x Weigh the pretreated raw materials from step 1 using a Mettler Toledo 204E precision electronic balance (accuracy: 0.0001 g). The total mass of the sheet-like CoCrNi multi-principal component alloy powder and graphene powder is approximately 200 g, and the powder is placed in a vacuum drying oven and dried at 200°C for 24–48 h. After drying, the prepared CoCrNi multi-principal component alloy powder and graphene powder are removed and packaged under an argon atmosphere for use in step 3.
[0026] Step 3: Low-energy ball milling of sheet-like CoCrNi multi-principal component alloy powder and graphene powder to prepare graphene / CoCrNi multi-principal component alloy composite powder. The specific method includes: under an argon atmosphere, adding the powder packaged in Step 2 into a ball mill jar, removing the glove box, and fixing it on an omnidirectional planetary ball mill for low-energy ball milling to prepare the graphene / CoCrNi multi-principal component alloy composite powder. During low-energy ball milling, stainless steel balls with a diameter of 8-10 mm are used, with a ball-to-material ratio of (3-5):1, and a milling speed of 90-150 rpm. The ball milling process is intermittent, with an effective milling time of 1-2 hours, a milling run time of 19-21 minutes, and a milling pause time of 9-11 minutes. After the milling process, the ball mill jar is removed and transferred to the glove box. Under an argon atmosphere, the composite powder is removed and vacuum-sealed for use in Step 4.
[0027] Step 4: The graphene / CoCrNi multi-principal-element alloy composite powder from Step 3 is extracted and densified by spark plasma sintering. The specific method includes: extracting the graphene / CoCrNi multi-principal-element alloy composite powder from Step 3 and densifying it by spark plasma sintering. During spark plasma sintering densification, the treatment environment is a vacuum environment, the heating rate is 100~150 ℃ / min, the sintering temperature is 900~1000 ℃, the sintering pressure is 30~40 MPa, the holding time is 20~30 min, and the cooling rate is 150~200 ℃ / min. A sintering mold is selected. A 30 mm graphite mold was used. Continuous vacuum was required during sintering to prevent high-temperature oxidation of the sample. The diameter of the prepared multilayered graphene / CoCrNi multi-principal-element alloy wear-resistant composite sample was [missing information]. 30 mm in diameter and 20 mm in height.
[0028] The segmented ball milling method employed in the above-mentioned scheme of this invention involves pre-high-speed ball milling of spherical CoCrNi multi-principal alloy particles to obtain sheet-like CoCrNi multi-principal alloy particles as carrier particles. Then, low-energy ball milling is used to mix graphene with the sheet-like CoCrNi multi-principal alloy powder, allowing the sheet-like CoCrNi multi-principal alloy powder to carry the graphene. The sheet-like CoCrNi multi-principal alloy powder has a high aspect ratio, which not only provides a larger specific surface area but also typically exhibits spontaneous stacking behavior with parallel orientation under gravity. On one hand, the large specific surface area of the sheet-like CoCrNi multi-principal alloy powder is beneficial for the adhesion of two-dimensional planar graphene, reducing the intrinsic agglomeration behavior of graphene. On the other hand, the sheet-like CoCrNi multi-principal alloy powder has the characteristic of spontaneous parallel stacking orientation; therefore, the sheet-like CoCrNi multi-principal alloy powder carrying graphene, after densification and high-temperature sintering, ultimately achieves a self-assembled layered structure. Finally, the segmented ball milling method can effectively avoid structural damage to graphene caused by high-speed ball milling and effectively reduce structural damage caused by ball milling. By changing the shape of the original powder (i.e., spherical CoCrNi multi-principal alloy powder), the active interface area between graphene and CoCrNi multi-principal alloy is increased, thereby promoting the nucleation of in-situ precipitated phases and increasing the volume fraction of in-situ precipitated phases. Based on this, 3.0 wt.% graphene was uniformly dispersed on the surface of sheet-like CoCrNi multi-principal alloy matrix powder using a low-energy ball milling method to prepare a layered graphene / CoCrNi multi-principal alloy wear-resistant composite material. The microstructure of the layered graphene / CoCrNi multi-principal alloy wear-resistant composite material prepared according to the method of this invention shows that it consists of a relatively soft FCC solid solution phase and a relatively hard Cr7C3 carbide phase generated by in-situ reaction, exhibiting good wear resistance and solving the two major problems of poor wear resistance of single-phase FCC structure CoCrNi multi-principal alloy and difficulty in dispersing graphene. Compared with existing conventional graphene / CoCrNi multi-principal-element alloy wear-resistant composite materials, this preparation method can effectively reduce graphene agglomeration and significantly improve preparation efficiency.
[0029] Example 1: In this embodiment, the mass ratio of CoCrNi multi-principal alloy powder to graphene in the multi-layered graphene / CoCrNi multi-principal alloy wear-resistant composite material is 1:0.01, i.e., 1.0 wt.% graphene. The specific preparation method includes the following steps: Step 1: Preparation of flake-shaped CoCrNi multi-principal alloy powder: The spherical CoCrNi multi-principal alloy powder raw material was dried and then ball-milled. Specifically, the spherical CoCrNi multi-principal alloy powder was placed in a vacuum drying oven and dried at 200℃ for 24 h. After drying, the corresponding spherical CoCrNi multi-principal alloy powder was transferred to a glove box and sealed in a ball milling jar under an argon atmosphere. The ball milling jar was then removed from the glove box and fixed on an omnidirectional planetary ball mill for high-energy ball milling, thus preparing the flake-shaped CoCrNi multi-principal alloy powder. A 1 L stainless steel vacuum ball milling jar was selected, and stainless steel balls with a diameter of 8 mm were used, with a ball-to-material ratio of 8:1. Intermittent ball milling was used, with the ball milling speed, effective ball milling time, and ball milling run / stop time set to 220 rpm, 4 h, and 20 min / 10 min, respectively. After the ball milling process, the ball milling jar was removed and transferred to the glove box. Under an argon atmosphere, the sheet-like CoCrNi multi-principal-element alloy powder is removed and packaged for use in step 2.
[0030] Step 2: Prepare multi-principal component alloy powder and graphene powder, and weigh the sheet-like CoCrNi multi-principal component alloy powder and graphene powder at a mass ratio of 1:0.01. Specifically, the method involves weighing the pretreated raw materials from Step 1 using a Mettler Toledo 204E precision electronic balance (accuracy: 0.0001 g) at a predetermined material mass fraction of 1.0 wt.%. The total mass of the sheet-like CoCrNi multi-principal component alloy powder and graphene powder is 202 g, and the powder is dried in a vacuum drying oven at 200°C for 24 h. After drying, the prepared CoCrNi multi-principal component alloy powder and graphene powder are removed and packaged under an argon atmosphere for use in Step 3.
[0031] Step 3: Low-energy ball milling of sheet-like CoCrNi multi-principal component alloy powder and graphene powder to prepare graphene / CoCrNi multi-principal component alloy composite powder. The specific method includes: adding the powder packaged in Step 2 into a ball mill jar under an argon atmosphere, removing the glove box, and fixing it on an omnidirectional planetary ball mill for low-energy ball milling to prepare the graphene / CoCrNi multi-principal component alloy composite powder. During low-energy ball milling, stainless steel balls with a diameter of 8 mm are used, with a ball-to-powder ratio of 3:1. The ball milling process is intermittent, with the ball milling speed, effective ball milling time, and ball milling run / stop time set to 90 rpm, 1 h, and 20 min / 10 min, respectively. After the ball milling process, the ball mill jar is removed and transferred to the glove box. Under an argon atmosphere, the composite powder is removed and vacuum-sealed for use in Step 4.
[0032] Step 4: The graphene / CoCrNi multi-principal component alloy composite powder from Step 3 is extracted and densified by spark plasma sintering. Specifically, the graphene / CoCrNi multi-principal component alloy composite powder from Step 3 is extracted and densified by spark plasma sintering. During the spark plasma sintering densification process, the treatment environment is a vacuum environment, and the heating rate, sintering temperature, sintering pressure, holding time, and cooling rate are set to 100 ℃ / min, 900 ℃, 30 MPa, 20 min, and 150 ℃ / min, respectively. A sintering mold is selected. A 30 mm graphite mold was used. Continuous vacuum was required during sintering to prevent high-temperature oxidation of the sample. The diameter of the prepared multilayered graphene / CoCrNi multi-principal-element alloy wear-resistant composite sample was [missing information]. 30 mm in diameter and 20 mm in height.
[0033] Example 2: In this embodiment, the mass ratio of CoCrNi multi-principal alloy powder to graphene in the multi-layered graphene / CoCrNi multi-principal alloy wear-resistant composite material is 1:0.015, i.e., 1.5 wt.% graphene. The specific preparation method includes the following steps: Step 1: Preparation of flake-shaped CoCrNi multi-principal alloy powder: The spherical CoCrNi multi-principal alloy powder raw material was dried and then ball-milled. Specifically, the spherical CoCrNi multi-principal alloy powder was placed in a vacuum drying oven and dried at 200℃ for 24 h. After drying, the corresponding spherical CoCrNi multi-principal alloy powder was transferred to a glove box and sealed in a ball milling jar under an argon atmosphere. The ball milling jar was then removed from the glove box and fixed on an omnidirectional planetary ball mill for high-energy ball milling, thus preparing the flake-shaped CoCrNi multi-principal alloy powder. A 1 L stainless steel vacuum ball milling jar was selected, and stainless steel balls with a diameter of 10 mm were used, with a ball-to-material ratio of 10:1. Intermittent ball milling was used, with the ball milling speed, effective ball milling time, and ball milling run / stop time set to 240 rpm, 6 h, and 20 min / 10 min, respectively. After the ball milling process, the ball milling jar was removed and transferred to the glove box. Under an argon atmosphere, the sheet-like CoCrNi multi-principal-element alloy powder is removed and packaged for use in step 2.
[0034] Step 2: Prepare multi-principal component alloy powder and graphene powder, and weigh the sheet-like CoCrNi multi-principal component alloy powder and graphene powder at a mass ratio of 1:0.015. The specific method includes: weighing the pretreated raw materials from Step 1 using a Mettler Toledo 204E precision electronic balance (accuracy: 0.0001 g) according to a predetermined material mass fraction of 1. The total mass of the sheet-like CoCrNi multi-principal component alloy powder and graphene powder is 203 g, and it is placed in a vacuum drying oven and dried at 200°C for 48 h. After drying, the prepared CoCrNi multi-principal component alloy powder and graphene powder are removed under an argon atmosphere and packaged for use in Step 3.
[0035] Step 3: Low-energy ball milling of sheet-like CoCrNi multi-principal component alloy powder and graphene powder to prepare graphene / CoCrNi multi-principal component alloy composite powder. The specific method includes: adding the powder packaged in Step 2 into a ball mill jar under an argon atmosphere, removing the glove box, and fixing it on an omnidirectional planetary ball mill for low-energy ball milling to prepare the graphene / CoCrNi multi-principal component alloy composite powder. During low-energy ball milling, stainless steel balls with a diameter of 10 mm are used, with a ball-to-powder ratio of 5:1. The ball milling process is intermittent, with the ball milling speed, effective ball milling time, and ball milling run / stop time set to 150 rpm, 2 h, and 20 min / 10 min, respectively. After the ball milling process, the ball mill jar is removed and transferred to the glove box. Under an argon atmosphere, the composite powder is removed and vacuum-sealed for use in Step 4.
[0036] Step 4: The graphene / CoCrNi multi-principal component alloy composite powder from Step 3 is extracted and densified by spark plasma sintering. Specifically, the graphene / CoCrNi multi-principal component alloy composite powder from Step 3 is extracted and densified by spark plasma sintering. During spark plasma sintering densification, the treatment environment is a vacuum environment, and the heating rate, sintering temperature, sintering pressure, holding time, and cooling rate are set to 150 ℃ / min, 1000 ℃, 40 MPa, 30 min, and 200 ℃ / min, respectively. A sintering mold is selected. A 30 mm graphite mold was used. Continuous vacuum was required during sintering to prevent high-temperature oxidation of the sample. The diameter of the prepared multilayered graphene / CoCrNi multi-principal-element alloy wear-resistant composite sample was [missing information]. 30 mm in diameter and 20 mm in height.
[0037] Example 3: In this embodiment, the mass ratio of CoCrNi multi-principal alloy powder to graphene in the multi-layered graphene / CoCrNi multi-principal alloy wear-resistant composite material is 1:0.03, i.e., 3.0 wt.% graphene. The specific preparation method includes the following steps: Step 1: Preparation of flake-shaped CoCrNi multi-principal alloy powder: The spherical CoCrNi multi-principal alloy powder raw material was dried and then ball-milled. Specifically, the spherical CoCrNi multi-principal alloy powder was placed in a vacuum drying oven and dried at 200℃ for 24 h. After drying, the corresponding spherical CoCrNi multi-principal alloy powder was transferred to a glove box and sealed in a ball milling jar under an argon atmosphere. The ball milling jar was then removed from the glove box and fixed on an omnidirectional planetary ball mill for high-energy ball milling, thus preparing the flake-shaped CoCrNi multi-principal alloy powder. A 1 L stainless steel vacuum ball milling jar was selected, and stainless steel balls with a diameter of 9 mm were used, with a ball-to-material ratio of 9:1. Intermittent ball milling was used, with the ball milling speed, effective ball milling time, and ball milling run / stop time set to 230 rpm, 5 h, and 20 min / 10 min, respectively. After the ball milling process, the ball milling jar was removed and transferred to the glove box. Under an argon atmosphere, the sheet-like CoCrNi multi-principal-element alloy powder is removed and packaged for use in step 2.
[0038] Step 2: Prepare multi-principal component alloy powder and graphene powder, and weigh the sheet-like CoCrNi multi-principal component alloy powder and graphene powder at a mass ratio of 1:0.03. The specific method includes: weighing the pretreated raw materials from Step 1 using a Mettler Toledo 204E precision electronic balance (accuracy: 0.0001 g) according to a predetermined material mass fraction of 3.0 wt.%. The total mass of the sheet-like CoCrNi multi-principal component alloy powder and graphene powder is 206 g, and it is placed in a vacuum drying oven and dried at 200°C for 36 h. After drying, the prepared CoCrNi multi-principal component alloy powder and graphene powder are removed under an argon atmosphere and packaged for use in Step 3.
[0039] Step 3: Low-energy ball milling of sheet-like CoCrNi multi-principal component alloy powder and graphene powder to prepare graphene / CoCrNi multi-principal component alloy composite powder. The specific method includes: adding the powder packaged in Step 2 into a ball mill jar under an argon atmosphere, removing the glove box, and fixing it on an omnidirectional planetary ball mill for low-energy ball milling to prepare the graphene / CoCrNi multi-principal component alloy composite powder. During low-energy ball milling, stainless steel balls with a diameter of 9 mm are used, with a ball-to-powder ratio of 4:1. The ball milling process is intermittent, with the ball milling speed, effective ball milling time, and ball milling run / stop time set to 120 rpm, 1.5 h, and 20 min / 10 min, respectively. After the ball milling process, the ball mill jar is removed and transferred to the glove box. Under an argon atmosphere, the composite powder is removed and vacuum-sealed for use in Step 4.
[0040] Step 4: The graphene / CoCrNi multi-principal component alloy composite powder from Step 3 is extracted and densified by spark plasma sintering. Specifically, the graphene / CoCrNi multi-principal component alloy composite powder from Step 3 is extracted and densified by spark plasma sintering. During the spark plasma sintering densification process, the treatment environment is a vacuum environment, and the heating rate, sintering temperature, sintering pressure, holding time, and cooling rate are set to 120 ℃ / min, 950 ℃, 35 MPa, 25 min, and 180 ℃ / min, respectively. A sintering mold is selected. A 30 mm graphite mold was used. Continuous vacuum was required during sintering to prevent high-temperature oxidation of the sample. The diameter of the prepared multilayered graphene / CoCrNi multi-principal-element alloy wear-resistant composite sample was [missing information]. 30 mm in diameter and 20 mm in height.
[0041] Comparative Example 1 To highlight the role of the laminated structure of the graphene / CoCrNi multi-principal alloy wear-resistant composite material in Example 3, a graphene / CoCrNi multi-principal alloy composite material with the same composition as in Example 3 was prepared using a conventional high-energy ball milling powder metallurgy method. Specifically, the graphene / CoCrNi multi-principal alloy wear-resistant composite material was prepared by conventional high-energy ball milling, wherein the content of CoCrNi multi-principal alloy powder and graphene was in a mass ratio of 1:0.03. The specific preparation method includes the following steps: Step 1: Prepare CoCrNi multi-principal component alloy powder and graphene powder, and weigh spherical CoCrNi multi-principal component alloy powder and graphene powder at a mass ratio of 1:0.03. The specific method includes: weighing and mixing the materials according to a predetermined material mass fraction of 3.0 wt.% using a Mettler Toledo 204E precision electronic balance (accuracy: 0.0001 g). The total mass of the spherical CoCrNi multi-principal component alloy powder and graphene powder is 206 g, and the powder is placed in a vacuum drying oven and dried at 200°C for 36 h. After drying, the prepared CoCrNi multi-principal component alloy powder and graphene powder are removed and packaged under an argon atmosphere for use in Step 2.
[0042] Step 2 involves high-energy ball milling of spherical CoCrNi multi-principal alloy powder and graphene powder to prepare graphene / CoCrNi multi-principal alloy composite powder. The specific method includes: adding the powder packaged in Step 1 into a ball mill jar under an argon atmosphere, removing the glove box, and fixing it on an omnidirectional planetary ball mill for high-energy ball milling to prepare the graphene / CoCrNi multi-principal alloy composite powder. A 1 L stainless steel vacuum ball mill jar is selected, and stainless steel balls with a diameter of 9 mm are used, with a ball-to-powder ratio of 6:1. The ball milling process employs intermittent ball milling, with the ball milling speed, effective ball milling time, and ball milling run / stop time set to 220 rpm, 6.5 h (the total ball milling time is the same as the 5 h high-energy ball milling and 1.5 h low-energy ball milling total of 6.5 h) and 20 min / 10 min respectively. After the ball milling process is completed, the ball mill jar is removed and transferred to the glove box. Under an argon atmosphere, the composite powder is removed and vacuum-sealed for use in step 3.
[0043] Step 3: The graphene / CoCrNi multi-principal component alloy composite powder from Step 2 is extracted and densified by spark plasma sintering. Specifically, the graphene / CoCrNi multi-principal component alloy composite powder from Step 2 is extracted and densified by spark plasma sintering. During the spark plasma sintering densification process, the treatment environment is a vacuum environment, and the heating rate, sintering temperature, sintering pressure, holding time, and cooling rate are set to 120 ℃ / min, 950 ℃, 35 MPa, 25 min, and 180 ℃ / min, respectively. A sintering mold is selected. A 30 mm graphite mold was used. Continuous vacuum was required during sintering to prevent high-temperature oxidation of the sample. The diameter of the prepared graphene / CoCrNi multi-principal-element alloy wear-resistant composite sample was [missing information]. 30 mm in diameter and 20 mm in height.
[0044] Comparative Example 2 To compare the reinforcing effect of graphene, a CoCrNi multi-principal element alloy was prepared using the traditional powder metallurgy method of high-energy ball milling. The specific preparation method is as follows: Step 1: Weigh the CoCrNi multi-principal element alloy powder. Specifically, use a Mettler Toledo 204E precision electronic balance (accuracy: 0.0001 g) to weigh 200 g of spherical CoCrNi multi-principal element alloy powder, and place it in a vacuum drying oven at 200°C for 36 h. After drying, remove the prepared CoCrNi multi-principal element alloy powder under an argon atmosphere and package it for use in Step 2.
[0045] Step 2: High-energy ball milling of spherical CoCrNi multi-principal element alloy powder. The specific method includes: under an argon atmosphere, adding the powder packaged in Step 1 to a grinding jar, removing the glove box, and fixing it on an omnidirectional planetary ball mill for high-energy ball milling to prepare CoCrNi multi-principal element alloy powder. A 1 L stainless steel vacuum grinding jar is selected, and stainless steel balls with a diameter of 9 mm are used, with a ball-to-powder ratio set at 6:1. Intermittent ball milling is employed, with the grinding speed, effective grinding time, and grinding run / stop time set at 230 rpm, 6.5 h (the total grinding time is the same as the 5 h high-energy ball milling and 1.5 h low-energy ball milling total of 6.5 h) and 20 min / 10 min, respectively. After the grinding process, the grinding jar is removed and transferred to the glove box. Under an argon atmosphere, the powder is removed and vacuum-sealed for use in Step 3.
[0046] Step 3: The CoCrNi multi-principal element alloy powder from Step 2 is extracted and densified by spark plasma sintering. The specific method includes: extracting the CoCrNi multi-principal element alloy powder from Step 2 and densifying it by spark plasma sintering. During the spark plasma sintering densification process, the treatment environment is a vacuum environment, and the heating rate, sintering temperature, sintering pressure, holding time, and cooling rate are set to 120 ℃ / min, 950 ℃, 35 MPa, 25 min, and 180 ℃ / min, respectively. A sintering mold is selected. A 30 mm graphite mold was used. Continuous vacuum was required during sintering to prevent high-temperature oxidation of the sample. The diameter of the prepared CoCrNi multi-principal-element alloy wear-resistant composite sample was [missing information]. 30 mm in diameter and 20 mm in height.
[0047] Figure 1 The image shows the SEM image of the microstructure of the 1.0 wt.% multi-principal-element alloy wear-resistant composite material with a stacked structure of graphene / CoCrNi prepared in Example 1. Figure 1As can be seen, the CoCrNi multi-principal element alloy exhibits a significant discontinuous lamellar morphology, and the sintering process has no significant impact on the morphology of the lamellars. Graphene is distributed around the CoCrNi multi-principal element alloy.
[0048] Figure 2 The image shows the SEM image of the microstructure of the 1.5 wt.% multi-principal-element alloy wear-resistant composite material with a stacked structure of graphene / CoCrNi prepared in Example 2. Figure 2 As can be seen, the CoCrNi multi-principal-element alloy exhibits a significant discontinuous lamellar morphology, and the sintering process has no significant effect on the morphology of the lamellars.
[0049] Figures 3(a)-3(c) show the structural schematic diagram and SEM images of the 3.0 wt.% layered graphene / CoCrNi multi-principal-element alloy wear-resistant composite material prepared in Example 3. Figure 3(a) is the structural schematic diagram, and Figures 3(b) and 3(c) are the SEM images of the microstructure with in-plane and cross-sectional orientations, respectively. Sheet-like MPEA powders with a high diameter-to-thickness ratio (as shown in Figure 3(a)) will naturally align in a parallel manner under external normal force; therefore, a self-assembled layered structure can be achieved through sheet powder metallurgy technology. For Gr / CoCrNi MPEA... AL The composite material, as shown in the plan view of Figure 3(b), reveals that the CoCrNi MPEA layer may have slightly bent during densification, resulting in a flower-like morphology visible from the top view. After etching the MPEA matrix, the residual graphene and in-situ carbides are clearly identifiable, as shown in the embedded image in Figure 3(b). Gr / CoCrNi MPEA AL Cross-sectional views of the composite material reveal a distinct “masonry structure” of in-situ carbides (Figure 3(c)), indicating uniform dispersion of graphene in the CoCrNi MPEA matrix. In summary, the optimized self-assembly strategy ensures uniform dispersion of graphene in the CoCrNi multi-principal alloy matrix, significantly increasing the upper limit of graphene addition in this type of composite material.
[0050] Figures 4(a) and 4(b) show the structural schematic and SEM images of the 3.0 wt.% layered graphene / CoCrNi multi-principal alloy wear-resistant composite material prepared in Comparative Example 1. Figure 4(a) is the structural schematic, and Figure 4(b) is the SEM image of the microstructure. Unlike the sheet-like CoCrNi multi-principal alloy powder of Example 3, the spherical CoCrNi multi-principal alloy powder (as shown in Figure 4(a)) makes it difficult to achieve uniform dispersion of graphene. As can be seen from Figure 4(b), during sintering, the diffusion of carbon atoms leads to in-situ precipitates at both grain boundaries and within the grains. The surface morphology of the graphene / CoCrNi multi-principal alloy wear-resistant composite material prepared by the traditional powder metallurgy method of high-energy ball milling exhibits a quasi-continuous spherical microstructure, and Cr7C3 carbides show obvious agglomeration at the primary powder boundaries. The excessive addition of graphene prevents uniform dispersion, resulting in clustered in-situ precipitates, thus weakening the wear resistance.
[0051] Figure 5 The XRD patterns of the 3.0 wt.% multilayered graphene / CoCrNi multi-principal element alloy wear-resistant composite material prepared in Example 3, the graphene / CoCrNi multi-principal element alloy wear-resistant composite material prepared in Comparative Example 1, and the CoCrNi multi-principal element alloy prepared in Comparative Example 2 are shown. Figure 5 It can be seen that the microstructure of Example 3 consists of two phases: an FCC solid solution phase and an in-situ reacted Cr7C3 carbide phase.
[0052] Figure 6 This diagram illustrates the wear rate results of the multilayered graphene / CoCrNi multi-principal alloy wear-resistant composite materials prepared in Examples 1-3, Comparative Example 1, and Comparative Example 2. Friction and wear tests were conducted according to the national standard GB / T 45880-2025. The wear rates of the multilayered graphene / CoCrNi multi-principal alloy wear-resistant composite materials prepared in Examples 1-3 were 1.83 × 10⁻⁶, respectively. - 5 mm 3 ·N -1 ·m -1 1.03×10 -5 mm 3 ·N -1 ·m -1 and 4.3×10 -6 mm 3 ·N -1 ·m -1 Compared with the CoCrNi multi-principal element alloy prepared in Comparative Example 2 (3.68 × 10⁻⁶), -5 mm 3 ·N -1 ·m-1 The graphene / CoCrNi multi-principal-element alloy wear-resistant composite material prepared in Comparative Example 1 (2.17 × 10⁻⁶) and Comparative Example 1 were also tested. -5 mm 3 ·N -1 ·m -1 Compared to the previous method, the wear resistance of the multilayered graphene / CoCrNi multi-principal alloy wear-resistant composite material is improved by an order of magnitude.
[0053] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.
[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.
Claims
1. A method for preparing a multi-principal-element alloy wear-resistant composite material with a layered graphene / CoCrNi structure, characterized in that, The process includes the following: Spherical CoCrNi multi-principal-element alloy powder was processed into flake-shaped CoCrNi multi-principal-element alloy powder by ball milling. Graphene powder was mixed with sheet-like CoCrNi multi-principal alloy powder and ball-milled to allow the sheet-like CoCrNi multi-principal alloy powder to carry graphene powder, thus obtaining graphene / CoCrNi multi-principal alloy composite powder. The graphene / CoCrNi multi-principal-element alloy composite powder was densified by spark plasma sintering to obtain the layered graphene / CoCrNi multi-principal-element alloy wear-resistant composite material.
2. The method for preparing a multi-principal-element alloy wear-resistant composite material with a stacked structure of graphene / CoCrNi according to claim 1, characterized in that, In a protective atmosphere, spherical CoCrNi multi-principal element alloy powder is processed into flake CoCrNi multi-principal element alloy powder by ball milling. The ball milling balls are stainless steel balls with a diameter of 8~10 mm, the ball-to-material ratio is (8~10):1, and the ball milling speed is 220~240 rpm. The ball milling process adopts intermittent ball milling, with an effective ball milling time of 4~6 h, a ball milling running time of 19~21 min, and a ball milling stop time of 9~11 min.
3. The method for preparing a multi-principal-element alloy wear-resistant composite material with a stacked structure of graphene / CoCrNi according to claim 1, characterized in that, It also includes the following processes: The spherical CoCrNi multi-principal component alloy powder was vacuum dried to remove moisture, and then the vacuum-dried spherical CoCrNi multi-principal component alloy powder was processed into flake CoCrNi multi-principal component alloy powder by ball milling.
4. The method for preparing a multi-principal-element alloy wear-resistant composite material with a stacked structure of graphene / CoCrNi according to claim 1, characterized in that, Graphene powder and sheet-like CoCrNi multi-principal-element alloy powder are mixed at a mass ratio of 0.01-0.
03.
5. The method for preparing a multi-principal-element alloy wear-resistant composite material with a stacked structure of graphene / CoCrNi according to claim 1, characterized in that, In a protective atmosphere, graphene powder and flake-shaped CoCrNi multi-principal-element alloy powder are mixed and ball-milled. During ball milling, stainless steel balls with a diameter of 8-10 mm are used, the ball-to-material ratio is (3-5):1, and the ball milling speed is 90-150 rpm. The ball milling process is intermittent, with an effective ball milling time of 1-2 hours, a ball milling running time of 19-21 minutes, and a ball milling pause time of 9-11 minutes.
6. A method for preparing a multilayered graphene / CoCrNi multi-principal-element alloy wear-resistant composite material according to claim 2 or 5, characterized in that, Argon is used as the protective atmosphere.
7. The method for preparing a multilayered graphene / CoCrNi multi-principal-element alloy wear-resistant composite material according to claim 1, characterized in that, It also includes the following processes: Graphene powder was vacuum dried to remove moisture. The vacuum-dried graphene powder was then mixed with sheet-like CoCrNi multi-principal-element alloy powder and ball-milled.
8. The method for preparing a multilayered graphene / CoCrNi multi-principal-element alloy wear-resistant composite material according to claim 1, characterized in that, When densifying the graphene / CoCrNi multi-principal-element alloy composite powder by spark plasma sintering: the treatment environment is a vacuum environment, the heating rate is 100~150 ℃ / min, the sintering temperature is 900~1000 ℃, the sintering pressure is 30~40 MPa, the holding time is 20~30 min, and the cooling rate is 150~200 ℃ / min.
9. The method for preparing a multi-principal-element alloy wear-resistant composite material with a stacked structure of graphene / CoCrNi according to claim 1, characterized in that, The spherical CoCrNi multi-principal-element alloy powder has a particle size of 15~45 μm and a purity of not less than 99.95 wt.%.
10. A multi-principal-element alloy wear-resistant composite material with a stacked structure of graphene / CoCrNi prepared by any one of the preparation methods of claims 1-9.