High-hardness and high-strength alloy powder for laser cladding and preparation process thereof

Abstract

The application relates to the technical field of alloy powder materials, in particular to a high-hardness and high-strength alloy powder for laser cladding and a preparation process thereof, which is used for solving the problems that the existing alloy powder cannot simultaneously have hardness and strength, some alloy powder has high hardness but the improvement of the hardness sacrifices the strength, or vice versa, the strength is high but the hardness is insufficient; the alloy powder adopts a high-entropy alloy as a matrix and adds modified ceramic powder as a reinforcing phase; the material has high hardness, excellent strength and toughness balance, and good fracture toughness, and has low wear rate; the matrix has a FCC+BCC dual-phase structure and has strength and plasticity; the modified ceramic particles are metallurgically combined with the matrix and have no gap and no air hole; the alloy powder has excellent high-temperature hardness and high-temperature wear resistance; a dense composite oxide layer is formed on the surface, can effectively block the inward diffusion of oxygen elements, and has good high-temperature oxidation resistance.

Description

Technical Field

[0001] This invention relates to the field of alloy powder materials technology, specifically to a high-hardness, high-strength alloy powder for laser cladding and its preparation process. Background Technology

[0002] Laser cladding technology is a technique that uses a high-energy laser beam to efficiently clad alloy powder onto the surface of a substrate material to improve the wear resistance and corrosion resistance of the substrate material. This technology is widely used in many fields such as machinery, aerospace, and mold making. It is favored because it can locally improve material properties and has the advantages of high efficiency, energy saving, and low cost. In the laser cladding process, the quality of the alloy powder directly affects the performance of the cladding layer.

[0003] Traditional laser cladding alloy powders typically contain iron and nickel alloys, which are mainly used to improve the wear resistance and corrosion resistance of materials. However, existing alloy powders generally suffer from insufficient hardness and strength. Some alloy powders have high hardness, but the increase in hardness comes at the expense of strength, or vice versa. These unbalanced properties make products prone to wear and cracking when subjected to high stress or harsh working environments, thus affecting the product's service life and performance.

[0004] Therefore, the development of a high-hardness, high-strength alloy powder for laser cladding and its preparation process is of great significance in the field of alloy powder materials technology. Summary of the Invention

[0005] In order to overcome the above-mentioned technical problems, the purpose of this invention is to provide a high-hardness and high-strength alloy powder for laser cladding and its preparation process; it solves the problem that existing alloy powders cannot simultaneously possess both hardness and strength, and that some alloy powders, although having high hardness, sacrifice strength for increased hardness, or conversely, have high strength but insufficient hardness.

[0006] The objective of this invention can be achieved through the following technical solutions: In a first aspect, this application provides a high-hardness, high-strength alloy powder for laser cladding, comprising the following components by weight: 85-92 parts of high-entropy alloy matrix powder and 5-9 parts of modified ceramic powder; The high-entropy alloy matrix powder is composed of the following substances in mass percentage: Cobalt 10-25%, Chromium 10-20%, Nickel 10-25%, Aluminum 5-15%, Titanium 5-20%, with the balance being iron.

[0007] In a preferred embodiment of the present invention, the high-entropy alloy matrix powder is composed of the following substances in mass percentage: cobalt 18-20%, chromium 16-18%, nickel 19-20%, aluminum 10-13%, titanium 14-16%, with the balance being iron.

[0008] In a preferred embodiment of the present invention, the high-entropy alloy matrix powder is prepared by the following steps: Aluminum powder, cobalt powder, chromium powder, iron powder, nickel powder, and titanium powder are dry-mixed for 5-10 minutes to obtain a matrix powder. The matrix powder is then added to a planetary ball mill under argon protection, with a ball-to-powder ratio of 10-15:1. Anhydrous ethanol is added, and the mixture is ball-milled at 300-400 r / min for 15-20 hours. The milled slurry is then placed in a vacuum drying oven and dried at 60℃ for 6-8 hours. It is then transferred to a tube furnace and heated to 1200-1250℃ at a rate of 8-10℃ / min under argon protection, held for 40-60 minutes, and cooled to 25℃ in the furnace. The mixture is then sieved using a vibrating screen and dried in a vacuum drying oven at 100-120℃ for 1-2 hours to obtain a high-entropy alloy matrix powder.

[0009] In a preferred embodiment of the present invention, the ratio of the matrix powder to anhydrous ethanol is 90-100g:40-60mL.

[0010] In a preferred embodiment of the present invention, the modified ceramic powder is prepared by the following steps: Tungsten carbide powder is immersed in a pretreatment solution and ultrasonically treated for 15-30 minutes. The pretreated tungsten carbide powder is then added to a chemical plating solution, and the pH is adjusted to 4.8 with ammonia. Ultrasonic plating is then performed at 70-85℃ and 200-300 rpm for 30-60 minutes with stirring. The mixture is filtered, and the precipitate is washed 2-3 times with distilled water. The precipitate is then dried in a vacuum drying oven at 80-100℃ for 2-4 hours to obtain modified tungsten carbide. Titanium dioxide and carbon black are then added to a three-dimensional electroplating solution. In a dynamic mixer, the ball-to-material ratio is 4-6:1, and the mixture is ball-milled for 30 minutes to obtain a mixture. The mixture is then placed in a high-energy ball mill for mechanical activation, with a ball-to-material ratio of 4:1 and an activation time of 2-4 hours. The activated mixture is then added to a microwave sintering furnace, vacuumed, and protected with nitrogen gas. It is then microwave-heated at 1000-1200℃ and held for 1-2 hours to obtain modified titanium carbide. The modified tungsten carbide and modified titanium carbide are then dry-mixed for 30 minutes to obtain modified ceramic powder.

[0011] In a preferred embodiment of the present invention, the ratio of tungsten carbide powder, pretreatment solution, electroless plating solution, titanium dioxide, and carbon black is 5-8g:250mL:250mL:4-6g:1.8-2.4g; the particle size of the tungsten carbide powder is 30-50μm; the particle size of the titanium dioxide is 200nm; the particle size of the carbon black is 20μm; the pretreatment solution is a mixed aqueous solution of hydrofluoric acid, nitric acid, and ammonium fluoride, wherein the hydrofluoric acid... The concentrations of the solvents are 34.5 g / L, nitric acid 28 g / L, and ammonium fluoride 3 g / L, with a solid-liquid ratio of 20 g / L. The electroless plating solution is a mixed aqueous solution of nickel sulfate hexahydrate, sodium hypophosphite, sodium citrate, and lactic acid, wherein the concentrations of nickel sulfate hexahydrate, sodium hypophosphite, sodium citrate, and lactic acid are 28 g / L, and the solid-liquid ratio is 20 g / L. The mass fraction of the ammonia solution is 28%.

[0012] Secondly, this application provides a process for preparing high-hardness, high-strength alloy powder for laser cladding, comprising the following steps: Step 1: Weigh out 85-92 parts of high-entropy alloy matrix powder and 5-9 parts of modified ceramic powder according to the weight ratio; Step 2: Add the high-entropy alloy matrix powder and modified ceramic powder to a ball mill with a ball-to-material ratio of 5:1. Dry mix at a speed of 250-300 r / min for 2-3 hours. Place the mixture in a vacuum tube furnace and heat it to 1200-1250℃ at a rate of 8-12℃ / min. Hold the temperature for 45-60 minutes and cool it to 25℃ with the furnace. Sieve the mixture using a vibrating screen and dry it in a vacuum drying oven at 100-120℃ for 1-2 hours to obtain high-hardness and high-strength alloy powder for laser cladding.

[0013] The beneficial effects of this invention are: This invention discloses a high-hardness, high-strength alloy powder for laser cladding and its preparation process. The process involves dry mixing, sintering, sieving, and drying of a high-entropy alloy matrix powder and modified ceramic powder to obtain the high-hardness, high-strength alloy powder for laser cladding. This alloy powder exhibits high hardness, excellent strength-toughness balance, good fracture toughness, and a low wear rate. The matrix has an FCC+BCC dual-phase structure, combining strength and plasticity. The modified ceramic particles form a metallurgical bond with the matrix, resulting in a seamless and pore-free structure with excellent high-temperature hardness and high-temperature wear resistance. A dense composite oxide layer forms on the surface, effectively preventing oxygen diffusion and providing good high-temperature oxidation resistance.

[0014] In the process of preparing high-hardness and high-strength alloy powder for laser cladding, a high-entropy alloy matrix powder was first prepared. Under the high-speed impact of grinding balls, aluminum powder, cobalt powder, chromium powder, iron powder, nickel powder, and titanium powder repeatedly underwent cold welding, crushing, and re-welding, resulting in solid-state diffusion between elements to form a BCC solid solution. The high mixing entropy of the multi-principal elements inhibited the formation of intermetallic compounds and promoted the formation of a simple solid solution structure, thus obtaining a high-entropy alloy matrix powder. Plastic deformation refined the grain size, which significantly improved the yield strength and increased the number of grain boundaries, providing more rapid channels for subsequent diffusion. The powder was transferred to a tube furnace and underwent a phase transformation at high temperature, transforming the BCC solid solution into a two-phase structure in which FCC solid solution and BCC solid solution coexist. The BCC phase has large lattice distortion and significant solid solution strengthening effect, providing high strength. The FCC phase has multiple slip systems and good plasticity, providing good fracture toughness. The two-phase interface acts as an effective barrier to dislocation movement, and the coordinated deformation of the two phases can delay crack propagation.

[0015] In the preparation of high-hardness, high-strength alloy powder for laser cladding, modified ceramic powder was first prepared. Nitric acid in the pretreatment solution served as an oxidant, forming a thin layer of tungsten oxide on the surface of tungsten carbide particles. Hydrofluoric acid in the pretreatment solution reacted with tungsten oxide to generate soluble fluorine complexes, forming micro-roughness and active sites on the tungsten carbide surface. Defects, dangling bonds, and oxygen-containing functional groups formed on the pretreated tungsten carbide surface. These active sites could serve as nucleation centers for electroless nickel plating. On the pretreated and activated tungsten carbide surface, nickel ions captured electrons and were reduced to metallic nickel, which was deposited on the tungsten carbide surface. Some sodium hypophosphite was reduced to elemental phosphorus and co-deposited with nickel to form a Ni-P alloy layer. During the laser cladding process, the nickel-coated tungsten carbide layer preferentially melted, and nickel elements were incorporated into the matrix. Tungsten carbide particles partially dissolved and reacted with iron and cobalt in the matrix to generate complex carbides. These in-situ generated carbides formed a co-deposition with the matrix. The lattice / semi-coherent interface generates strong interfacial strengthening and load transfer effects. Titanium dioxide and carbon black are mechanically activated in a high-energy ball mill, increasing specific surface area and contact area. Ball milling introduces defects such as oxygen vacancies and dislocations into the titanium dioxide lattice, reducing the activation energy of subsequent carbothermic reduction reactions. The two raw materials are uniformly mixed at the nanoscale to form a composite structure. Some titanium dioxide undergoes amorphization during ball milling, improving reactivity. This is then added to a microwave sintering furnace for carbothermic reduction to synthesize submicron-sized modified titanium carbide. Submicron-sized titanium carbide particles partially dissolve during laser cladding, releasing titanium and carbon atoms into the matrix to participate in the formation of the L12 phase, enhancing precipitation strengthening. Carbon atoms form carbides with chromium, iron, etc., providing Orowan strengthening. Undissolved TiC particles act as a hard framework, bearing load transfer while pinning grain boundaries, inhibiting grain growth, and improving the material's wear resistance and toughness. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram showing the hardness performance test results of the cladding layers prepared by high-hardness and high-strength alloy powder for laser cladding in Examples 1-3 and Comparative Examples 1-3 of the present invention.

[0018] Figure 2 This is a schematic diagram showing the tensile strength test results of the cladding layers prepared by high-hardness and high-strength alloy powder for laser cladding in Examples 1-3 and Comparative Examples 1-3 of the present invention.

[0019] Figure 3 This is a schematic diagram showing the yield strength test results of the cladding layers prepared by high-hardness and high-strength alloy powder for laser cladding in Examples 1-3 and Comparative Examples 1-3 of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1: This embodiment describes a preparation process for high-hardness, high-strength alloy powder for laser cladding, including the following steps: Step S1: Dry mix aluminum powder, cobalt powder, chromium powder, iron powder, nickel powder, and titanium powder for 5 minutes to obtain 90g of matrix powder; add 90g of matrix powder to a planetary ball mill, purge with argon gas, with a ball-to-powder ratio of 10:1, add 40mL of anhydrous ethanol, and mix and ball mill at 300r / min for 15h. Place the ball-milled slurry in a vacuum drying oven and dry at 60℃ for 6h. Transfer to a tube furnace, heat to 1200℃ at a rate of 8℃ / min under argon gas protection, hold for 40min, cool to 25℃ with the furnace, sieve using a vibrating screen, and dry in a 100℃ vacuum drying oven for 1h to obtain high-entropy alloy matrix powder; the matrix powder is composed of the following substances in the following mass percentages: cobalt 18%, chromium 16%, nickel 19%, aluminum 10%, titanium 14%, and iron 23%; Step S2: Immerse 5g of tungsten carbide powder with a particle size of 30μm in 250mL of pretreatment solution and sonicate for 15min. Add the pretreated tungsten carbide powder to 250mL of chemical plating solution, adjust the pH to 4.8 with 28% ammonia, and perform ultrasonic-assisted plating at 70℃ and 200r / min for 30min. Filter, wash the precipitate twice with distilled water, and dry in a vacuum drying oven at 80℃ for 2h to obtain modified tungsten carbide. Add 4g of titanium dioxide with a particle size of 200nm and 1.8g of carbon black with a particle size of 20μm to a three-dimensional motion mixer with a ball-to-material ratio of 4:1, and ball mill for 30min to obtain a mixture. Place the mixture in a high-energy ball mill for mechanical activation with a ball-to-material ratio of 4:1 for 2h. The activated mixture was added to a microwave sintering furnace, evacuated, and protected with nitrogen gas. It was then microwave-heated at 1000℃ for 1 hour to obtain modified titanium carbide. The modified tungsten carbide and modified titanium carbide were dry-mixed for 30 minutes to obtain modified ceramic powder. The pretreatment solution was a mixed aqueous solution of hydrofluoric acid, nitric acid, and ammonium fluoride, with a hydrofluoric acid concentration of 34.5 g / L, a nitric acid concentration of 28 g / L, and an ammonium fluoride concentration of 3 g / L, and a solid-liquid ratio of 20 g / L. The chemical plating solution was a mixed aqueous solution of nickel sulfate hexahydrate, sodium hypophosphite, sodium citrate, and lactic acid, with a nickel sulfate hexahydrate concentration of 28 g / L, a sodium hypophosphite concentration of 28 g / L, a sodium citrate concentration of 18 g / L, and a lactic acid concentration of 9.6 g / L, and a solid-liquid ratio of 20 g / L. Step S3: Weigh out 85 parts of high-entropy alloy matrix powder and 5 parts of modified ceramic powder according to the weight ratio. Step S4: Add the high-entropy alloy matrix powder and modified ceramic powder to a ball mill with a ball-to-material ratio of 5:1. Dry mix at 250 r / min for 2 h. Place in a vacuum tube furnace and heat to 1200℃ at a rate of 8℃ / min. Hold at this temperature for 45 min. Cool to 25℃ with the furnace. Sieve using a vibrating screen. Dry in a vacuum drying oven at 100℃ for 1 h to obtain high-hardness and high-strength alloy powder for laser cladding.

[0022] Example 2: This embodiment describes a preparation process for high-hardness, high-strength alloy powder for laser cladding, including the following steps: Step S1: Dry mix aluminum powder, cobalt powder, chromium powder, iron powder, nickel powder, and titanium powder for 8 minutes to obtain a matrix powder; add 95g of the matrix powder to a planetary ball mill, purge with argon gas, with a ball-to-powder ratio of 13:1, add 50mL of anhydrous ethanol, and mix and ball mill at 350r / min for 18h. Place the ball-milled slurry in a vacuum drying oven and dry at 60℃ for 7h. Transfer it to a tube furnace, heat it to 1225℃ at a rate of 9℃ / min under argon gas protection, hold for 50min, cool it to 25℃ with the furnace, sieve it using a vibrating screen, and dry it in a vacuum drying oven at 110℃ for 1.5h to obtain a high-entropy alloy matrix powder; the matrix powder is composed of the following substances in the following mass percentages: cobalt 19%, chromium 17%, nickel 19%, aluminum 12%, titanium 15%, and iron 18%; Step S2: Immerse 6.5g of tungsten carbide powder with a particle size of 40μm in 250mL of pretreatment solution and sonicate for 25min. Add the pretreated tungsten carbide powder to 250mL of chemical plating solution, adjust the pH to 4.8 with 28% ammonia, and perform ultrasonic-assisted plating at 80℃ and 250r / min for 45min. Filter, wash the precipitate three times with distilled water, and dry in a vacuum drying oven at 90℃ for 3h to obtain modified tungsten carbide. Add 5g of titanium dioxide with a particle size of 200nm and 2.1g of carbon black with a particle size of 20μm to a three-dimensional motion mixer at a ball-to-material ratio of 5:1 and ball mill for 30min to obtain a mixture. Place the mixture in a high-energy ball mill for mechanical activation at a ball-to-material ratio of 4:1 for 3h. The activated mixture was added to a microwave sintering furnace, evacuated, and protected with nitrogen gas. It was then microwave-heated at 1100℃ for 1.5 hours to obtain modified titanium carbide. The modified tungsten carbide and modified titanium carbide were dry-mixed for 30 minutes to obtain modified ceramic powder. The pretreatment solution was a mixed aqueous solution of hydrofluoric acid, nitric acid, and ammonium fluoride, with a hydrofluoric acid concentration of 34.5 g / L, a nitric acid concentration of 28 g / L, and an ammonium fluoride concentration of 3 g / L, and a solid-liquid ratio of 20 g / L. The electroless plating solution was a mixed aqueous solution of nickel sulfate hexahydrate, sodium hypophosphite, sodium citrate, and lactic acid, with a nickel sulfate hexahydrate concentration of 28 g / L, a sodium hypophosphite concentration of 28 g / L, a sodium citrate concentration of 18 g / L, and a lactic acid concentration of 9.6 g / L, and a solid-liquid ratio of 20 g / L. Step S3: Weigh out 88 parts of high-entropy alloy matrix powder and 7 parts of modified ceramic powder according to the weight ratio. Step S4: Add the high-entropy alloy matrix powder and modified ceramic powder to a ball mill with a ball-to-material ratio of 5:1. Dry mix at 275 r / min for 2.5 h. Place in a vacuum tube furnace and heat to 1225 °C at a rate of 10 °C / min. Hold at this temperature for 50 min. Cool to 25 °C with the furnace. Sieve using a vibrating screen. Dry in a vacuum drying oven at 110 °C for 1.5 h to obtain high-hardness, high-strength alloy powder for laser cladding.

[0023] Example 3: This embodiment describes a preparation process for high-hardness, high-strength alloy powder for laser cladding, including the following steps: Step S1: Dry mix aluminum powder, cobalt powder, chromium powder, iron powder, nickel powder, and titanium powder for 10 min to obtain matrix powder; add 100g of matrix powder to a planetary ball mill, purge with argon gas, with a ball-to-powder ratio of 15:1, add 60mL of anhydrous ethanol, and mix and ball mill at 400r / min for 20h. Place the ball-milled slurry in a vacuum drying oven and dry at 60℃ for 8h. Transfer to a tube furnace, heat to 1250℃ at a rate of 10℃ / min under argon gas protection, hold for 60min, cool to 25℃ with the furnace, sieve using a vibrating screen, and dry in a vacuum drying oven at 120℃ for 2h to obtain high-entropy alloy matrix powder; the matrix powder is composed of the following substances in the following mass percentages: cobalt 20%, chromium 18%, nickel 20%, aluminum 13%, titanium 16%, and iron 13%; Step S2: Immerse 8g of tungsten carbide powder with a particle size of 50μm in 250mL of pretreatment solution and sonicate for 30min. Add the pretreated tungsten carbide powder to 250mL of chemical plating solution, adjust the pH to 4.8 with 28% ammonia, and perform ultrasonic-assisted plating at 85℃ and 300r / min for 60min. Filter, wash the precipitate three times with distilled water, and dry in a vacuum drying oven at 100℃ for 4h to obtain modified tungsten carbide. Add 6g of titanium dioxide with a particle size of 200nm and 2.4g of carbon black with a particle size of 20μm to a three-dimensional motion mixer at a ball-to-material ratio of 6:1 and ball mill for 30min to obtain a mixture. Place the mixture in a high-energy ball mill for mechanical activation at a ball-to-material ratio of 4:1 and activation time of 4 minutes. h, the activated mixture is added to a microwave sintering furnace, vacuumed, protected with nitrogen, and microwave heated at 1200℃ for 2 hours to obtain modified titanium carbide; the above modified tungsten carbide and modified titanium carbide are dry-mixed for 30 minutes to obtain modified ceramic powder; the pretreatment solution is a mixed aqueous solution of hydrofluoric acid, nitric acid and ammonium fluoride, wherein the concentration of hydrofluoric acid is 34.5 g / L, the concentration of nitric acid is 28 g / L and the concentration of ammonium fluoride is 3 g / L, and the solid-liquid ratio is 20 g / L; the chemical plating solution is a mixed aqueous solution of nickel sulfate hexahydrate, sodium hypophosphite, sodium citrate and lactic acid, wherein the concentration of nickel sulfate hexahydrate is 28 g / L, the concentration of sodium hypophosphite is 28 g / L, the concentration of sodium citrate is 18 g / L and the concentration of lactic acid is 9.6 g / L, and the solid-liquid ratio is 20 g / L; Step S3: Weigh out 92 parts of high-entropy alloy matrix powder and 9 parts of modified ceramic powder according to the weight ratio; Step S4: Add the high-entropy alloy matrix powder and modified ceramic powder to a ball mill with a ball-to-material ratio of 5:1. Dry mix at 300 r / min for 3 h. Place in a vacuum tube furnace and heat to 1250℃ at a rate of 12℃ / min. Hold at this temperature for 60 min. Cool to 25℃ with the furnace. Sieve using a vibrating screen. Dry in a vacuum drying oven at 120℃ for 2 h to obtain high-hardness and high-strength alloy powder for laser cladding.

[0024] Comparative Example 1: This comparative example illustrates a preparation process for high-hardness, high-strength alloy powder used in laser cladding, comprising the following steps: Step S1: Dry mix aluminum powder, cobalt powder, chromium powder, iron powder, nickel powder, and titanium powder for 8 minutes to obtain a matrix powder; add 95g of the matrix powder to a planetary ball mill, purge with argon gas, with a ball-to-powder ratio of 13:1, add 50mL of anhydrous ethanol, and mix and ball mill at 350r / min for 18h. Place the ball-milled slurry in a vacuum drying oven and dry at 60℃ for 7h. Transfer it to a tube furnace, heat it to 1225℃ at a rate of 9℃ / min under argon gas protection, hold for 50min, cool it to 25℃ with the furnace, sieve it using a vibrating screen, and dry it in a vacuum drying oven at 110℃ for 1.5h to obtain a high-hardness, high-strength alloy powder for laser cladding; the matrix powder is composed of the following substances in the following mass percentages: cobalt 19%, chromium 17%, nickel 19%, aluminum 12%, titanium 15%, and iron 18%.

[0025] Comparative Example 2: This comparative example illustrates a preparation process for high-hardness, high-strength alloy powder used in laser cladding, comprising the following steps: Step S1: Dry mix aluminum powder, cobalt powder, chromium powder, iron powder, nickel powder, and titanium powder for 8 minutes to obtain a matrix powder; add 95g of the matrix powder to a planetary ball mill, purge with argon gas, with a ball-to-powder ratio of 13:1, add 50mL of anhydrous ethanol, and mix and ball mill at 350r / min for 18h. Place the ball-milled slurry in a vacuum drying oven and dry at 60℃ for 7h. Transfer it to a tube furnace, heat it to 1225℃ at a rate of 9℃ / min under argon gas protection, hold for 50min, cool it to 25℃ with the furnace, sieve it using a vibrating screen, and dry it in a vacuum drying oven at 110℃ for 1.5h to obtain a high-entropy alloy matrix powder; the matrix powder is composed of the following substances in the following mass percentages: cobalt 19%, chromium 17%, nickel 19%, aluminum 12%, titanium 15%, and iron 18%; Step S2: Add 5g of titanium dioxide with a particle size of 200nm and 2.1g of carbon black with a particle size of 20μm to a three-dimensional motion mixer with a ball-to-material ratio of 5:1. Mix and ball mill for 30min to obtain a mixture. Place the mixture in a high-energy ball mill for mechanical activation with a ball-to-material ratio of 4:1 and an activation time of 3h. Add the activated mixture to a microwave sintering furnace, evacuate, and purge with nitrogen for protection. Microwave heat at 1100℃ for 1.5h to obtain modified ceramic powder. Step S3: Weigh out 88 parts of high-entropy alloy matrix powder and 7 parts of modified ceramic powder according to the weight ratio. Step S4: Add the high-entropy alloy matrix powder and modified ceramic powder to a ball mill with a ball-to-material ratio of 5:1. Dry mix at 275 r / min for 2.5 h. Place in a vacuum tube furnace and heat to 1225 °C at a rate of 10 °C / min. Hold at this temperature for 50 min. Cool to 25 °C with the furnace. Sieve using a vibrating screen. Dry in a vacuum drying oven at 110 °C for 1.5 h to obtain high-hardness, high-strength alloy powder for laser cladding.

[0026] Comparative Example 3: This comparative example illustrates a preparation process for high-hardness, high-strength alloy powder used in laser cladding, comprising the following steps: Step S1: Dry mix aluminum powder, cobalt powder, chromium powder, iron powder, nickel powder, and titanium powder for 8 minutes to obtain a matrix powder; add 95g of the matrix powder to a planetary ball mill, purge with argon gas, with a ball-to-powder ratio of 13:1, add 50mL of anhydrous ethanol, and mix and ball mill at 350r / min for 18h. Place the ball-milled slurry in a vacuum drying oven and dry at 60℃ for 7h. Transfer it to a tube furnace, heat it to 1225℃ at a rate of 9℃ / min under argon gas protection, hold for 50min, cool it to 25℃ with the furnace, sieve it using a vibrating screen, and dry it in a vacuum drying oven at 110℃ for 1.5h to obtain a high-entropy alloy matrix powder; the matrix powder is composed of the following substances in the following mass percentages: cobalt 19%, chromium 17%, nickel 19%, aluminum 12%, titanium 15%, and iron 18%; Step S2: Immerse 6.5g of tungsten carbide powder with a particle size of 40μm in 250mL of pretreatment solution and sonicate for 25min. Add the pretreated tungsten carbide powder to 250mL of chemical plating solution, adjust the pH to 4.8 with 28% ammonia water, and perform ultrasonic-assisted plating at 80℃ and 250r / min for 45min with stirring. Filter, wash the precipitate three times with distilled water, and dry in a vacuum drying oven at 90℃ for 3h to obtain modified ceramic powder; the pretreatment... The liquid is a mixed aqueous solution of hydrofluoric acid, nitric acid, and ammonium fluoride, wherein the concentration of hydrofluoric acid is 34.5 g / L, the concentration of nitric acid is 28 g / L, and the concentration of ammonium fluoride is 3 g / L, with a solid-liquid ratio of 20 g / L; the electroless plating solution is a mixed aqueous solution of nickel sulfate hexahydrate, sodium hypophosphite, sodium citrate, and lactic acid, wherein the concentration of nickel sulfate hexahydrate is 28 g / L, the concentration of sodium hypophosphite is 28 g / L, the concentration of sodium citrate is 18 g / L, and the concentration of lactic acid is 9.6 g / L, with a solid-liquid ratio of 20 g / L; Step S3: Weigh out 88 parts of high-entropy alloy matrix powder and 7 parts of modified ceramic powder according to the weight ratio. Step S4: Add the high-entropy alloy matrix powder and modified ceramic powder to a ball mill with a ball-to-material ratio of 5:1. Dry mix at 275 r / min for 2.5 h. Place in a vacuum tube furnace and heat to 1225 °C at a rate of 10 °C / min. Hold at this temperature for 50 min. Cool to 25 °C with the furnace. Sieve using a vibrating screen. Dry in a vacuum drying oven at 110 °C for 1.5 h to obtain high-hardness, high-strength alloy powder for laser cladding.

[0027] The high-hardness, high-strength alloy powders prepared in Examples 1-3 and Comparative Examples 1-3 were used for laser cladding on the surface of 45# steel. The process parameters were: laser power 2200W, scanning speed 800mm / min, spot diameter 2mm, powder feed rate 6g / min, overlap rate 30%, protective gas argon, flow rate 20L / min. Before cladding, the surface of 45# steel was polished with sandpaper from 80# to 800#, ultrasonically cleaned with acetone for 15min, and preheated at 200℃ for 2h. After cladding, the steel was placed in a vacuum furnace and held at 500℃ for 2h, then cooled to room temperature with the furnace to obtain the cladding layer. The cladding layer was tested for hardness using a small force Vickers hardness test according to standard GB / T 4340.1-2024 "Metallic Materials - Vickers Hardness Test - Part 1: Test Method". Standard 228.1-2021, "Metallic materials, tensile testing—Part 1: Test at room temperature," specifies the determination of tensile strength and yield strength; test results are as follows: Figure 1-3 As shown: Comparing Examples 1-3 with Comparative Examples 1-3: The performance differences between Examples 1-3 stem from the synergistic effect of the content of reinforcing elements such as aluminum and titanium in the high-entropy alloy matrix and the proportion of modified ceramic powder. Example 2, with a moderate content of aluminum, titanium, modified tungsten carbide, and modified titanium carbide, achieved the optimal dispersion distribution of L12-type nano-precipitates and double ceramic reinforcing phases in the matrix through ball milling, resulting in higher hardness and tensile strength. Example 3, with higher aluminum and titanium content and the largest ceramic addition, had slightly higher hardness, but the excessive titanium element led to an increase in brittle Laves phase at the grain boundaries, and the high titanium carbide content caused particle agglomeration, reducing tensile strength. In Example 1, the aluminum and titanium content was lower and the ceramic addition was the smallest, resulting in insufficient precipitation strengthening and dispersion strengthening effects, leading to lower hardness and strength. Comparing Example 2 with Comparative Example 1 shows that... Comparative Example 1 consists only of high-entropy alloy matrix powder, and its strengthening mainly relies on solid solution strengthening caused by aluminum and titanium elements and precipitation strengthening of L12-type nanophases precipitated during ball milling-heat treatment. In contrast, Example 2 introduces a dual ceramic reinforcing phase on the basis of matrix strengthening, which significantly improves strength and hardness. Comparing Example 2 with Comparative Example 2, it can be seen that Comparative Example 2 only adds modified titanium carbide ceramic. Although the dispersion strengthening effect of titanium carbide can improve hardness and strength, it lacks the supporting effect of tungsten carbide particles. The load is mainly borne by the matrix, and the titanium carbide particles are prone to rotation or detachment under stress. Comparing Example 2 with Comparative Example 3, it can be seen that Comparative Example 3 only adds modified tungsten carbide ceramic. Although tungsten carbide particles can provide good interfacial bonding and load transfer, the matrix region between micron-sized particles lacks effective strengthening and is prone to cracking.

[0028] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0029] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in this application, they should all fall within the protection scope of the present invention.

Claims

1. A high-hardness, high-strength alloy powder for laser cladding, characterized in that, Includes the following components by weight: 85-92 parts of high-entropy alloy matrix powder and 5-9 parts of modified ceramic powder; The high-entropy alloy matrix powder is prepared by the following steps: Aluminum powder, cobalt powder, chromium powder, iron powder, nickel powder, and titanium powder are dry-mixed to obtain a matrix powder. The matrix powder is then added to a ball mill, anhydrous ethanol is added, and the mixture is ball-milled, dried, sintered, cooled in the furnace, sieved using a vibrating screen, and dried to obtain a high-entropy alloy matrix powder.

2. The high-hardness, high-strength alloy powder for laser cladding according to claim 1, characterized in that, The high-entropy alloy matrix powder is composed of the following substances in the indicated mass percentages: cobalt 10-25%, chromium 10-20%, nickel 10-25%, aluminum 5-15%, titanium 5-20%, with the balance being iron.

3. The high-hardness, high-strength alloy powder for laser cladding according to claim 1, characterized in that, The high-entropy alloy matrix powder is composed of the following substances in the indicated mass percentages: cobalt 18-20%, chromium 16-18%, nickel 19-20%, aluminum 10-13%, titanium 14-16%, with the balance being iron.

4. The high-hardness, high-strength alloy powder for laser cladding according to claim 1, characterized in that, The ratio of the matrix powder to anhydrous ethanol is 90-100g:40-60mL.

5. The high-hardness, high-strength alloy powder for laser cladding according to claim 1, characterized in that, The modified ceramic powder is prepared by the following steps: Tungsten carbide powder was immersed in a pretreatment solution, ultrasonically treated, added to a chemical plating solution, pH adjusted with ammonia, and ultrasonically assisted plating was performed with stirring. The mixture was then filtered, the precipitate was washed, and dried to obtain modified tungsten carbide. Titanium dioxide and carbon black were mixed and ball-milled to obtain a mixture. The mixture was placed in a high-energy ball mill for mechanical activation and then microwave-heated in a microwave sintering furnace to obtain modified titanium carbide. The modified tungsten carbide and modified titanium carbide were then dry-mixed to obtain modified ceramic powder.

6. The high-hardness, high-strength alloy powder for laser cladding according to claim 5, characterized in that, The ratio of tungsten carbide powder, pretreatment solution, electroless plating solution, titanium dioxide, and carbon black is 5-8g:250mL:250mL:4-6g:1.8-2.4g; the particle size of the tungsten carbide powder is 30-50μm; the particle size of the titanium dioxide is 200nm; the particle size of the carbon black is 20μm; the pretreatment solution is a mixed aqueous solution of hydrofluoric acid, nitric acid, and ammonium fluoride, wherein the concentration of hydrofluoric acid is 34.5g / L, the concentration of nitric acid is 28g / L, and the concentration of ammonium fluoride is 3g / L, with a solid-liquid ratio of 20g / L; the electroless plating solution is a mixed aqueous solution of nickel sulfate hexahydrate, sodium hypophosphite, sodium citrate, and lactic acid, wherein the concentration of nickel sulfate hexahydrate is 28g / L, the concentration of sodium hypophosphite is 28g / L, the concentration of sodium citrate is 18g / L, and the concentration of lactic acid is 9.6g / L, with a solid-liquid ratio of 20g / L; the mass fraction of the ammonia water is 28%.

7. A preparation process for high-hardness, high-strength alloy powder for laser cladding as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Weigh out 85-92 parts of high-entropy alloy matrix powder and 5-9 parts of modified ceramic powder according to the weight ratio; Step 2: Add the high-entropy alloy matrix powder and modified ceramic powder to a ball mill, dry mix, sinter in a vacuum tube furnace, cool with the furnace, sieve with a vibrating screen, and dry to obtain high-hardness and high-strength alloy powder for laser cladding.

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