High-strength high-wear-resistance titanium alloy bar and preparation method thereof

Abstract

The application discloses a kind of high-strength high-wear-resistance titanium alloy bar and preparation method thereof, it is related to titanium alloy surface treatment technical field.Step 1: with titanium bar as base material, it is sequentially roughened, cold spraying alloy composite powder, heat treatment, and forms transition layer;Titanium alloy bar A is obtained;Step 2: titanium alloy bar A is polished and oil is removed, pickling, then nickel-graphene-cerium oxide layer is electroplated, and then laser post-processing is carried out, and wear-resistant layer is formed;High-strength high-wear-resistance titanium alloy bar is obtained;The alloy composite powder includes TC4 powder, boronized TC4 powder and CuNiIn powder one or more kinds.This application is with the TC4 type titanium bar of strength as matrix, and the surface is further strengthened, and transition layer is formed by cold spraying, then gradient electrodeposition process is used, and wear-resistant layer is effectively formed, and finally laser strengthening is used to effectively improve surface hardness.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy surface treatment, specifically to a high-strength, high-wear-resistant titanium alloy bar and its preparation method. Background Technology

[0002] Titanium alloy bars are widely used in aerospace, medical device and other technical fields due to their excellent specific strength and corrosion resistance. Among them, Ti-6Al-4V (TC4 type) is a medium-hardness α+β type alloy with low surface hardness, poor wear resistance and high coefficient of friction, which greatly limits its reliability and service life under conditions of friction and wear.

[0003] Currently, methods for improving the surface properties of titanium alloy bars typically include chemical heat treatment, vapor deposition, laser cladding, and electrodeposition. Among these, chemical heat treatment processes such as carburizing and nitriding suffer from the drawback of high processing temperatures affecting the microstructure of the substrate. While vapor deposition processes such as magnetron sputtering can produce coatings with excellent performance, they are costly and have limited industrial applicability. Laser cladding, on the other hand, can cause lattice distortion and significant residual stress. In comparison, electrodeposition technology is more widely used in metal surface modification due to its advantages such as minimal heat-affected zone, ease of operation, and wide applicability.

[0004] In the existing technology, nickel-based plating has the properties of dense structure and good wear resistance in the electroplating process of titanium alloy bars. However, the following defects still exist: First, the bonding strength between the electroplated layer and the titanium alloy substrate is insufficient, which makes it easy to crack and peel off under heavy load or impact conditions. Second, increasing the content of hard particles to improve hardness will lead to increased internal stress, increased brittleness and increased crack sensitivity of the coating. On the other hand, reducing the particle content will reduce the surface wear resistance.

[0005] In conclusion, solving the above problems and preparing a high-strength, high-wear-resistant titanium alloy rod is of great significance. Summary of the Invention

[0006] The purpose of this invention is to provide a high-strength, high-wear-resistant titanium alloy rod and its preparation method, so as to solve the problems mentioned in the background art.

[0007] A method for preparing a high-strength, high-wear-resistant titanium alloy rod includes the following steps:

[0008] Step 1: Using a titanium rod as the substrate, it is subjected to roughening, cold spraying with alloy composite powder, and heat treatment to form a transition layer; thus obtaining titanium alloy rod A.

[0009] Step 2: Polish and degrease titanium alloy rod A, pickle it, then electroplate a nickel-graphene-cerium oxide layer, followed by laser post-treatment to form a wear-resistant layer; thus obtaining a high-strength, high-wear-resistant titanium alloy rod.

[0010] The alloy composite powder includes one or more of TC4 powder, boronized TC4 powder, and CuNiIn powder.

[0011] In a more optimized manner, the alloy composite powder is composed of TC4 powder, boronized TC4 powder, and CuNiIn powder in a mass ratio of 55~65:20~25:15~20.

[0012] In this scheme, a specific ratio of TC4 powder, boronized TC4 powder, and CuNiIn powder is used as a transition layer. TC4 powder is the main powder, which is homologous to the substrate and can better adhere to the roughened substrate surface to form a continuous phase with the coating. The boronized TC4 powder contains a hard TiB phase, which has a dispersion strengthening effect on the transition layer. The introduced CuNiIn powder is relatively soft and acts as a binder and lubricant for the boronized TC4 powder, which helps to improve the density of the transition layer.

[0013] A more optimized method for preparing the boron-impregnated TC4 powder is as follows: TC4 powder and boron nitride are mixed and ball-milled; the mixture is transferred to a graphite mold, heated to 1000-1100℃ under vacuum at a rate of 80-150℃ / min, and sintered by spark plasma for 5-8 min under a pressure of 30-40 MPa. The mixture is then cooled in the furnace, crushed, and ground to obtain the boron-impregnated TC4 powder.

[0014] More optimally, the roughening is laser texturing, and the process parameters of the laser texturing are: under an argon atmosphere, grid scanning, laser power of 50~100W, scanning speed of 800~1200mm / s, and line spacing of 0.1~0.15mm;

[0015] In the process of cold spraying, the laser-textured substrate is preheated to 150~200℃; cold spraying is carried out with nitrogen as the gas type, spraying temperature of 600~700℃, spraying pressure of 3~4MPa, spraying distance of 20~30mm, and powder feeding rate of 20~25g / min.

[0016] The heat treatment process parameters are as follows: heat treatment at 700~720℃ for 20~30 minutes, air cooling, and then annealing at 400~500℃ for 1~2 hours.

[0017] During the process, laser texturing promotes interfacial bonding; after heat treatment, thermal diffusion bonding occurs between TC4 powder, boronized TC4 powder, and CuNiIn powder, effectively improving the bonding strength of the transition layer, reducing porosity in cold spraying, and increasing density; simultaneously, it releases the internal stress generated by cold spraying. Furthermore, the bonding between the hard TiB whiskers contained in the boronized TC4 powder and the soft CuNiIn is strengthened, forming a stable and dense transition layer, promoting subsequent electroplating. Due to the presence of CuNiIn powder, nickel can promote the subsequent deposition of the nickel-graphene-cerium oxide layer, improving electroplating adhesion and reducing stress.

[0018] In a more optimized manner, the pickling process involves sequentially using a hydrofluoric acid-nitric acid mixture and a phosphonic acid mixture; the hydrofluoric acid mixture comprises: 40-50 mL / L hydrofluoric acid, 100-120 mL / L nitric acid, 80-100 mL / L hydrogen peroxide, and the remainder being deionized water;

[0019] The phosphonic acid mixture has a pH of 3-3.5 and its raw materials include: 80-120 mL / L aminotrimethylphosphonic acid, 40-60 g / L citric acid, 20-40 mL / L hydrogen peroxide, 1-3 g / L ammonium fluoride, and the remainder is water.

[0020] During the pickling process, the sample is first immersed in a hydrofluoric acid mixture at room temperature for 30-60 seconds, then washed with water and dried with nitrogen; then it is pickled in a phosphonic acid mixture at 45-55°C for 1-5 minutes, then washed with water and dried with nitrogen.

[0021] During the process, to enhance the performance of the electroplated layer, a mixture of two acids, hydrofluoric acid and nitric acid, is used for pre-activation to form a relatively rough surface. Then, the surface roughness is refined in a phosphonic acid mixture to form uniform, high-density nano-pits, promoting subsequent electroplating. At the same time, the aminotrimethylphosphonic acid and citric acid contained therein have a strong complexing effect, which can thoroughly chelate and remove trace metal ion contaminants remaining from the first step, forming a uniform surface. In addition, aminotrimethylphosphonic acid can prevent secondary oxidation during the period from treatment to electroplating, and can perfectly wet the subsequent electroplating solution, while providing abundant nickel ion nucleation sites.

[0022] In a more optimized manner, during the electroplating process of the nickel-graphene-cerium oxide layer, the electroplating solution has a pH of 3.8~4.5 and includes the following raw materials: 300~320g / L nickel sulfate, 40~50g / L nickel chloride, 35~40g / L boric acid, 2~5g / L fluorinated graphene, 15~20g / L cerium oxide, 1~1.5g / L sodium dodecyl sulfate, 0.2~0.5g / L polyethylene glycol silane coupling agent, 1~2g / L sodium saccharin, and 20~30g / L sodium citrate.

[0023] In this scheme, fluorinated graphene and cerium oxide are used as wear-resistant particles in the electroplating solution to effectively improve the wear resistance of the electroplated nickel-graphene-cerium oxide layer. Fluorinated graphene, being sheet-like, provides solid lubrication and reduces the coefficient of friction; cerium oxide, being particulate and hard, provides dispersion reinforcement and inhibits wear, forming a composite wear-resistant network. To improve dispersibility, polyethylene glycol silane coupling agent is used as a dispersant to enhance the dispersion of the wear-resistant particles.

[0024] Compared to conventional graphene oxide, fluorinated graphene is more stable and has better dispersibility in the plating solution. Furthermore, fluorine atoms can form a stronger interfacial bond with nickel ions, resulting in better interlayer lubrication.

[0025] In a more optimized manner, the electroplating process is as follows: the electroplating solution temperature is 40~45℃, the anode is an electrolytic nickel plate, and the electroplating distance is 30~35mm; firstly, the cathode current density is 0.5~1A / dm² for activation for 30~60 seconds; then, high pulse current of 5~6A / dm² with a duty cycle of 30% is used for electrodeposition for 5~10 minutes; medium pulse current of 3~4A / dm² with a duty cycle of 40% is used for electrodeposition for 20~40 minutes; and low DC current density of 1~2A / dm² is used for electrodeposition for 10~15 minutes; throughout the entire process, ultrasonic dispersion with a frequency of 40~50 kHz is provided.

[0026] In this design, due to the use of two types of wear-resistant particles, a gradient electroplating process is employed to improve the density and wear resistance of the coating. First, electroactivation enhances surface properties. Then, a high-pulse undercoating promotes the co-deposition of wear-resistant particles, forming a dense composite underlayer with strong interfacial bonding. Next, a medium-pulse undercoating process is used to thicken the coating, ensuring uniform dispersion of the wear-resistant particles while achieving uniform thickness, thus improving the hardness and wear resistance of the coating. Finally, low-DC deposition makes the electrocrystallization process of nickel more gradual and orderly, reducing internal stress and minimizing the tendency for coating cracking. This process forms a gradient coating, improving the adhesion and wear resistance of the coating.

[0027] In a more optimized manner, during the laser post-processing, under an argon atmosphere, the laser power is 10-30W, the pulse width is <10 picoseconds, the repetition rate is 100-500kHz, the scanning speed is 1000-3000mm / s, the spot diameter is 30-50μm, and the energy density is 0.5-1.2J / cm². 2 .

[0028] Finally, the surface was subjected to laser strengthening treatment, which caused rapid remelting of the surface layer, thereby densifying and phase transformation, refining the surface grains, eliminating micro-defects, and improving surface properties. At the same time, the heat zone of the laser treatment is extremely shallow, which will not damage the overall bonding strength of the coating and the properties of the substrate.

[0029] Ideally, the titanium rod is a TC4 type titanium rod.

[0030] TC4 titanium rods are high-strength titanium rods. Their preparation process is as follows: TC4 titanium ingots are forged at 980~1150℃ (forging above the β phase transformation point), intermediate forging at 950~980℃ (in the α+β two-phase region or near the β region), precision forging at 750~950℃ (in the lower part of the α+β two-phase region), rolling, annealing at 650~800℃ (below the β phase transformation point), air cooling or furnace cooling; solution cooling at 870~890℃ followed by rapid cooling, aging at 500~580℃; turning or grinding; removing the surface oxide layer and embedded iron contaminants in a hydrofluoric acid-nitric acid mixture, and sandblasting or shot peening to improve the surface condition; thus obtaining TC4 titanium rods.

[0031] A more optimized method for preparing high-strength, high-wear-resistant titanium alloy rods yields high-strength, high-wear-resistant titanium alloy rods.

[0032] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: In this application, a high-strength TC4 type titanium rod is used as the substrate, and its surface is further strengthened. A transition layer is formed by cold spraying, and then a wear-resistant layer is effectively formed by gradient electrodeposition. Finally, laser strengthening is used to effectively improve the surface hardness.

[0033] The use of a cold-spray transition layer serves several advantages. First, compared to nitriding or direct laser cladding, which affect the microstructure and basic strength of the TC4 titanium rod substrate, this method does not affect the substrate strength. Second, compared to the previous electroplated nickel layer, the difference in thermal expansion coefficient affects the coating adhesion. By setting this transition layer, stress can be effectively buffered and the bonding strength improved. Third, the rough structure formed after cold spraying can promote the interfacial bonding of the coating.

[0034] The introduction of a specific pickling solution effectively improves the nucleation of the nickel layer and enhances the adhesion of the electroplated layer; it also works synergistically with the transition layer to improve the bonding strength of the plating layer and suppress crack formation and peeling.

[0035] In this process, a gradient electrodeposition technique is employed in the same electroplating solution containing fluorinated graphene and cerium dioxide to deposit a continuous gradient structure, effectively forming a high-hardness surface. The gradient deposition process effectively alleviates stress concentration and prevents brittle peeling of the high-hardness outer layer. Simultaneously, laser strengthening is used to rapidly densify the outermost layer, eliminating microscopic defects and effectively improving surface hardness.

[0036] Thus, high-strength, high-wear-resistant titanium alloy rods were produced without sacrificing the properties of the matrix, achieving effective improvements in surface wear resistance and bonding strength. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0038] It should be noted that the following quantities are by weight. There are no special restrictions on the manufacturers of the raw materials involved in this invention. Exemplary examples include: in the following embodiments, the fluorinated graphene sheet is 0.4~5μm, and the cerium oxide is 40~60nm; the CAS number of the polyethylene glycol silane coupling agent is 98358-37-3, and the graphene oxide is 0.5~5μm; all the above and other unmentioned raw materials are commercially available.

[0039] Example 1: A method for preparing a high-strength, high-wear-resistant titanium alloy rod, comprising the following steps:

[0040] Preliminary preparation: TC4 titanium ingots are forged at 1100℃, intermediate forged at 950℃, precision forged at 850℃, rolled, annealed at 750℃, and air-cooled or furnace-cooled; solution-treated at 880℃ followed by rapid cooling, and aged at 550℃; turned or ground; surface oxide layer and embedded iron contaminants are removed in a hydrofluoric acid-nitric acid mixture, and surface condition is improved by sandblasting or shot peening; high-strength TC4 titanium rods are obtained.

[0041] Preparation of boron-infiltrated TC4 powder: TC4 powder and boron nitride were mixed and ball-milled at a ratio of 5:1; the mixture was then transferred to a graphite mold and sintered under vacuum at a rate of 100℃ / min to 1050℃, followed by spark plasma sintering at a pressure of 35 MPa for 5 min. The mixture was then cooled in the furnace, crushed, and ground to obtain boron-infiltrated TC4 powder. The TC4 powder is homologous to TC4 type titanium ingots, and the boron nitride content was 0.15 wt%.

[0042] Step 1: Using a titanium rod as the substrate, laser texturing is performed under an argon atmosphere with grid scanning. The laser power is 60W, the scanning speed is 1000mm / s, and the line spacing is 0.1mm. Then, alloy composite powder is cold-sprayed onto the surface. During this process, the laser-textured substrate is preheated to 200℃. Cold spraying is performed using nitrogen gas at a spraying temperature of 680℃, a spraying pressure of 3MPa, a spraying distance of 25mm, and a powder feed rate of 20g / min. Next, heat treatment is performed: the substrate is held at 720℃ for 30 minutes, air-cooled, and then annealed at 450℃ for 2 hours. This forms a transition layer, resulting in titanium alloy rod A.

[0043] Step 2: The surface of titanium alloy rod A is mechanically polished and alkaline washed sequentially using 500-mesh, 1000-mesh, and 1400-mesh metallographic paper; then it is immersed in a hydrofluoric acid mixture at room temperature for 60 seconds, washed with water, and dried with nitrogen; then it is acid-washed in a phosphonic acid mixture at 50°C for 3 minutes, washed with water, and dried with nitrogen; it is then placed in an electroplating solution at a temperature of 45°C, with an electrolytic nickel plate as the anode and an electroplating distance of 30mm; first, it is activated with a cathode current density of 1A / dm² for 30 seconds; then, it is activated with a high pulse current of 5A / dm². Electrodeposition was performed for 8 minutes with a duty cycle of 30%; 30 minutes with a medium pulse current of 4 A / dm² and a duty cycle of 40%; and 10 minutes with a low DC current density of 1.5 A / dm². Throughout the process, ultrasonic dispersion at a frequency of 50 kHz was used for assisted dispersion. Laser post-processing was then performed under an argon atmosphere with a laser power of 20 W, a pulse width < 10 picoseconds, a repetition rate of 200 kHz, a scanning speed of 2000 mm / s, a spot diameter of 30 μm, and an energy density of 1 J / cm². 2 Thus, a wear-resistant layer is formed, resulting in a high-strength, high-wear-resistant titanium alloy rod.

[0044] In this embodiment, the alloy composite powder is composed of TC4 powder, boronized TC4 powder and CuNiIn powder in a mass ratio of 60:22:18.

[0045] The raw materials for the hydrofluoric acid mixture include: 50 mL / L hydrofluoric acid, 120 mL / L nitric acid, 100 mL / L hydrogen peroxide, and the remainder is deionized water;

[0046] The pH of the phosphonic acid mixture is 3.4. Its raw materials include: 120 mL / L aminotrimethylphosphonic acid, 50 g / L citric acid, 30 mL / L hydrogen peroxide, 2 g / L ammonium fluoride, and the remainder is water.

[0047] During the electroplating process of nickel-graphene-cerium oxide layer, the electroplating solution has a pH of 4.2 and includes the following raw materials: 300 g / L nickel sulfate, 45 g / L nickel chloride, 38 g / L boric acid, 3 g / L fluorinated graphene, 17 g / L cerium oxide, 1 g / L sodium dodecyl sulfate, 0.2~0.5 g / L polyethylene glycol silane coupling agent, 1.5 g / L sodium saccharin, and 25 g / L sodium citrate.

[0048] Example 2: A method for preparing a high-strength, high-wear-resistant titanium alloy rod, comprising the following steps:

[0049] Preliminary preparation: TC4 titanium ingots are forged at 1100℃, intermediate forged at 950℃, precision forged at 850℃, rolled, annealed at 750℃, and air-cooled or furnace-cooled; solution-treated at 880℃ followed by rapid cooling, and aged at 550℃; turned or ground; surface oxide layer and embedded iron contaminants are removed in a hydrofluoric acid-nitric acid mixture, and surface condition is improved by sandblasting or shot peening; high-strength TC4 titanium rods are obtained.

[0050] Preparation of boron-infiltrated TC4 powder: TC4 powder and boron nitride were mixed and ball-milled at a ratio of 5:1; the mixture was then transferred to a graphite mold and sintered under vacuum at a rate of 100℃ / min to 1050℃, followed by spark plasma sintering at a pressure of 35 MPa for 5 min. The mixture was then cooled in the furnace, crushed, and ground to obtain boron-infiltrated TC4 powder. The TC4 powder is homologous to TC4 type titanium ingots, and the boron nitride content was 0.15 wt%.

[0051] Step 1: Using a titanium rod as the substrate, laser texturing is performed under an argon atmosphere with grid scanning. The laser power is 60W, the scanning speed is 1000mm / s, and the line spacing is 0.1mm. Then, alloy composite powder is cold-sprayed onto the surface. During this process, the laser-textured substrate is preheated to 200℃. Cold spraying is performed using nitrogen gas at a spraying temperature of 680℃, a spraying pressure of 3MPa, a spraying distance of 25mm, and a powder feed rate of 20g / min. Next, heat treatment is performed: the substrate is held at 720℃ for 30 minutes, air-cooled, and then annealed at 450℃ for 2 hours. This forms a transition layer, resulting in titanium alloy rod A.

[0052] Step 2: The surface of titanium alloy rod A is mechanically polished and alkaline-washed sequentially using 500-mesh, 1000-mesh, and 1400-mesh metallographic paper. Then, it is immersed in a hydrofluoric acid mixture at room temperature for 60 seconds, rinsed with water, and dried with nitrogen. Next, it is acid-washed in a phosphonic acid mixture at 50°C for 3 minutes, rinsed with water, and dried with nitrogen. Finally, it is placed in an electroplating solution at 45°C, with an electrolytic nickel plate as the anode and a plating distance of 30mm. Activation is first performed with a cathode current density of 0.5A / dm² for 60 seconds, followed by activation with a high-pulse current of 5A / dm². ², Electrodeposition was performed with a duty cycle of 30% for 5 min; with a medium pulse current of 3 A / dm² and a duty cycle of 40% for 40 min; and with a low DC current density of 2 A / dm² for 10 min. Throughout the process, ultrasonic dispersion at a frequency of 50 kHz was used for assisted dispersion. Laser post-processing was then performed under an argon atmosphere, with a laser power of 20 W, a pulse width < 10 picoseconds, a repetition frequency of 200 kHz, a scanning speed of 2000 mm / s, a spot diameter of 30 μm, and an energy density of 1 J / cm². 2 Thus, a wear-resistant layer is formed, resulting in a high-strength, high-wear-resistant titanium alloy rod.

[0053] In this embodiment, the alloy composite powder is composed of TC4 powder, boronized TC4 powder and CuNiIn powder in a mass ratio of 55:25:20.

[0054] The raw materials for the hydrofluoric acid mixture include: 50 mL / L hydrofluoric acid, 120 mL / L nitric acid, 100 mL / L hydrogen peroxide, and the remainder is deionized water;

[0055] The pH of the phosphonic acid mixture is 3.4. Its raw materials include: 120 mL / L aminotrimethylphosphonic acid, 50 g / L citric acid, 30 mL / L hydrogen peroxide, 2 g / L ammonium fluoride, and the remainder is water.

[0056] During the electroplating process of nickel-graphene-cerium oxide layer, the electroplating solution has a pH of 4.2 and includes the following raw materials: 300 g / L nickel sulfate, 45 g / L nickel chloride, 38 g / L boric acid, 2 g / L fluorinated graphene, 18 g / L cerium oxide, 1 g / L sodium dodecyl sulfate, 0.2~0.5 g / L polyethylene glycol silane coupling agent, 1.5 g / L sodium saccharin, and 25 g / L sodium citrate.

[0057] Example 3: A method for preparing a high-strength, high-wear-resistant titanium alloy rod, comprising the following steps:

[0058] Preliminary preparation: TC4 titanium ingots are forged at 1100℃, intermediate forged at 950℃, precision forged at 850℃, rolled, annealed at 750℃, and air-cooled or furnace-cooled; solution-treated at 880℃ followed by rapid cooling, and aged at 550℃; turned or ground; surface oxide layer and embedded iron contaminants are removed in a hydrofluoric acid-nitric acid mixture, and surface condition is improved by sandblasting or shot peening; high-strength TC4 titanium rods are obtained.

[0059] Preparation of boron-infiltrated TC4 powder: TC4 powder and boron nitride were mixed and ball-milled at a ratio of 5:1; the mixture was then transferred to a graphite mold and sintered under vacuum at a rate of 100℃ / min to 1050℃, followed by spark plasma sintering at a pressure of 35 MPa for 5 min. The mixture was then cooled in the furnace, crushed, and ground to obtain boron-infiltrated TC4 powder. The TC4 powder is homologous to TC4 type titanium ingots, and the boron nitride content was 0.15 wt%.

[0060] Step 1: Using a titanium rod as the substrate, laser texturing is performed under an argon atmosphere with grid scanning. The laser power is 60W, the scanning speed is 1000mm / s, and the line spacing is 0.1mm. Then, alloy composite powder is cold-sprayed onto the surface. During this process, the laser-textured substrate is preheated to 200℃. Cold spraying is performed using nitrogen gas at a spraying temperature of 680℃, a spraying pressure of 3MPa, a spraying distance of 25mm, and a powder feed rate of 20g / min. Next, heat treatment is performed: the substrate is held at 720℃ for 30 minutes, air-cooled, and then annealed at 450℃ for 2 hours. This forms a transition layer, resulting in titanium alloy rod A.

[0061] Step 2: The surface of titanium alloy rod A is mechanically polished and alkaline washed sequentially using 500-mesh, 1000-mesh, and 1400-mesh metallographic paper. Then, it is immersed in a hydrofluoric acid mixture at room temperature for 60 seconds, rinsed with water, and dried with nitrogen. Next, it is acid-washed in a phosphonic acid mixture at 50°C for 3 minutes, rinsed with water, and dried with nitrogen. Finally, it is placed in an electroplating solution at 45°C, with an electrolytic nickel plate as the anode and a plating distance of 30mm. Activation is first performed with a cathode current density of 1A / dm² for 30 seconds, followed by activation with a high pulse current of 6A / dm². Electrodeposition was performed with a duty cycle of 30% for 5 minutes; with a medium pulse current of 4 A / dm² and a duty cycle of 40%, it was performed for 20 minutes; and with a low DC current density of 1 A / dm², it was performed for 10 minutes. Throughout the process, ultrasonic dispersion at a frequency of 50 kHz was used for assisted dispersion. Laser post-processing was then performed under an argon atmosphere with a laser power of 20 W, a pulse width < 10 picoseconds, a repetition frequency of 200 kHz, a scanning speed of 2000 mm / s, a spot diameter of 30 μm, and an energy density of 1 J / cm². 2 Thus, a wear-resistant layer is formed, resulting in a high-strength, high-wear-resistant titanium alloy rod.

[0062] In this embodiment, the alloy composite powder is composed of TC4 powder, boronized TC4 powder and CuNiIn powder in a mass ratio of 65:20:15.

[0063] The raw materials for the hydrofluoric acid mixture include: 50 mL / L hydrofluoric acid, 120 mL / L nitric acid, 100 mL / L hydrogen peroxide, and the remainder is deionized water;

[0064] The pH of the phosphonic acid mixture is 3.4. Its raw materials include: 120 mL / L aminotrimethylphosphonic acid, 50 g / L citric acid, 30 mL / L hydrogen peroxide, 2 g / L ammonium fluoride, and the remainder is water.

[0065] During the electroplating process of nickel-graphene-cerium oxide layer, the electroplating solution has a pH of 4.2 and includes the following raw materials: 300 g / L nickel sulfate, 45 g / L nickel chloride, 38 g / L boric acid, 5 g / L fluorinated graphene, 15 g / L cerium oxide, 1 g / L sodium dodecyl sulfate, 0.2~0.5 g / L polyethylene glycol silane coupling agent, 1.5 g / L sodium saccharin, and 25 g / L sodium citrate.

[0066] Comparative Example 1: During the cold spraying process, boronizing TC4 powder was not introduced, and the rest was the same as in Example 1; the difference lay in the following steps:

[0067] Step 1: Using a titanium rod as the substrate, laser texturing is performed under an argon atmosphere with grid scanning. The laser power is 60W, the scanning speed is 1000mm / s, and the line spacing is 0.1mm. Then, alloy composite powder is cold-sprayed onto the surface. During this process, the laser-textured substrate is preheated to 200℃. Cold spraying is performed using nitrogen gas at a spraying temperature of 600℃, a spraying pressure of 3MPa, a spraying distance of 25mm, and a powder feed rate of 20g / min. Next, heat treatment is performed: the substrate is held at 650℃ for 30 minutes, air-cooled, and then annealed at 450℃ for 2 hours. This forms a transition layer, resulting in titanium alloy rod A.

[0068] In this embodiment, the alloy composite powder is composed of TC4 powder and CuNiIn powder in a mass ratio of 80:20.

[0069] Comparative Example 2: During the cold spraying process, an excess of boron-impregnated TC4 powder was introduced, and the rest was the same as in Example 1; the difference lay in the following steps:

[0070] In this embodiment, the alloy composite powder is composed of TC4 powder, boronized TC4 powder and CuNiIn powder in a mass ratio of 52:30:18.

[0071] Comparative Example 3: In the electroplating process, a single process was used for electroplating, and the rest was the same as in Example 1; the difference was in the following steps:

[0072] Step 2: The surface of titanium alloy rod A is mechanically polished and alkaline washed sequentially using 500-mesh, 1000-mesh, and 1400-mesh metallographic paper. Then, it is immersed in a hydrofluoric acid mixture at room temperature for 60 seconds, washed with water, and dried with nitrogen. Next, it is acid-washed in a phosphonic acid mixture at 50°C for 3 minutes, washed with water, and dried with nitrogen. It is then placed in an electroplating solution at 45°C, with an electrolytic nickel plate as the anode and an electroplating distance of 30mm. Electrodeposition is performed for 48 minutes using a medium pulse current of 4A / dm² and a duty cycle of 40%. Throughout the process, ultrasonic dispersion at a frequency of 50kHz is used. Finally, laser post-processing is performed under an argon atmosphere with a laser power of 20W, a pulse width <10 picoseconds, a repetition frequency of 200kHz, a scanning speed of 2000mm / s, a spot diameter of 30μm, and an energy density of 1J / cm². 2 Thus, a wear-resistant layer is formed, resulting in a high-strength, high-wear-resistant titanium alloy rod.

[0073] Comparative Example 4: During the electroplating process, fluorinated graphene was replaced with graphene oxide, and the rest was the same as in Example 1; the difference lay in the following steps:

[0074] During the electroplating process of nickel-graphene-cerium oxide layer, the electroplating solution has a pH of 4.2 and includes the following raw materials: 300 g / L nickel sulfate, 45 g / L nickel chloride, 38 g / L boric acid, 3 g / L graphene oxide, 17 g / L cerium oxide, 1 g / L sodium dodecyl sulfate, 0.2~0.5 g / L polyethylene glycol silane coupling agent, 1.5 g / L sodium saccharin, and 25 g / L sodium citrate.

[0075] Comparative Example 5: Treatment with a single acid, otherwise the same as in Example 1; the difference lies in the following steps:

[0076] Step 2: The surface of titanium alloy rod A is mechanically polished and alkaline washed sequentially using 500-mesh, 1000-mesh, and 1400-mesh metallographic paper. Then, it is immersed in a hydrofluoric acid mixture at room temperature for 3 minutes, rinsed with water, and dried with nitrogen. It is then placed in an electroplating solution at 45°C, with an electrolytic nickel plate as the anode and a plating distance of 30 mm. First, it is activated with a cathode current density of 1 A / dm² for 30 seconds; then, it is electrodeposited for 8 minutes with a high pulse current of 5 A / dm² and a duty cycle of 30%. Electrodeposition was performed for 30 min with a medium pulse current of 4 A / dm² and a duty cycle of 40%, followed by electrodeposition for 10 min with a low DC current density of 1.5 A / dm². Throughout the process, ultrasonic dispersion at a frequency of 50 kHz was used for assisted dispersion. Laser post-processing was then performed under an argon atmosphere with a laser power of 20 W, a pulse width < 10 picoseconds, a repetition rate of 200 kHz, a scanning speed of 2000 mm / s, a spot diameter of 30 μm, and an energy density of 1 J / cm². 2 Thus, a wear-resistant layer is formed, resulting in a high-strength, high-wear-resistant titanium alloy rod.

[0077] Performance Test 1: The basic tests of the TC4 titanium rod were performed as follows: (1) the hydrogen content was determined according to GB / T4698.15-2011; (2) the room temperature tensile properties were determined according to GB / T228.1-2010; (3) the high magnification structure was determined according to GB / T5168-2020. The obtained data are shown in the table below:

[0078]

[0079] Conclusion: This study demonstrates that titanium rods possess high strength and toughness, making them suitable for applications requiring high mechanical properties and reliability. Furthermore, they are suitable for further surface strengthening treatments to enhance surface hardness and wear resistance, thereby improving their high wear resistance and expanding their applications under conditions of friction and wear.

[0080] Performance Test 2: (1) Microhardness was measured using a microhardness tester with a load of 5N and a loading time of 15 seconds; (2) A pin-disc friction and wear test was conducted with a load of 10N, a temperature of 600℃, a rotation speed of 560r / min, a friction radius of 3mm, and a test time of 60 minutes to measure the mass loss before and after the test and to measure the wear amount; (3) A scratch tester was used with a loading speed of 10N / min and a diamond indenter to measure the critical load at which peeling occurs; The obtained data are shown in the table below:

[0081]

[0082] Conclusion: The data in the table above show that a titanium alloy rod with high wear resistance was prepared in this application; the data of Comparative Examples 1 and 2 show that the introduction and excessive boronizing of TC4 powder have a significant impact on the bonding performance; Comparative Example 3 shows that a single electroplating process leads to a decrease in wear resistance and bonding strength; the data of Comparative Example 4 shows that changing fluorinated graphene to graphene oxide slightly reduces the relevant properties; the data of Comparative Example 5 shows that a single acid treatment affects the bonding performance.

[0083] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a high-strength, high-wear-resistant titanium alloy rod, characterized in that: Includes the following steps: Step 1: Using a titanium rod as the substrate, it is subjected to roughening, cold spraying with alloy composite powder, and heat treatment to form a transition layer; thus obtaining titanium alloy rod A. Step 2: Polish and degrease titanium alloy rod A, pickle it, then electroplate a nickel-graphene-cerium oxide layer, followed by laser post-treatment to form a wear-resistant layer; thus obtaining a high-strength, high-wear-resistant titanium alloy rod. The alloy composite powder is composed of TC4 powder, boronized TC4 powder and CuNiIn powder in a mass ratio of 55~65:20~25:15~20. During the pickling process, a mixture of hydrofluoric acid and nitric acid and a mixture of phosphonic acid are used sequentially for pickling; the pH of the phosphonic acid mixture is 3~3.5, and its raw materials include: 80~120mL / L aminotrimethylphosphonic acid, 40~60g / L citric acid, 20~40mL / L hydrogen peroxide, 1~3g / L ammonium bifluoride, and the remainder is water; During the electroplating process of the nickel-graphene-cerium oxide layer, the electroplating solution temperature is 40~45℃, the anode is an electrolytic nickel plate, and the electroplating distance is 30~35mm; initially, the cathode current density is 0.5~1A / dm. 2 Activation for 30-60 seconds; then with a high pulse current of 5-6 A / dm 2 Electrodeposition was performed with a duty cycle of 30% for 5-10 minutes; with a medium pulse current of 3-4 A / dm² and a duty cycle of 40% for 20-40 minutes; and with a low DC current density of 1-2 A / dm² for 10-15 minutes. Ultrasonic dispersion with a frequency of 40-50 kHz was used throughout the process. The electroplating solution has a pH of 3.8 to 4.5 and includes the following raw materials: 300 to 320 g / L nickel sulfate, 40 to 50 g / L nickel chloride, 35 to 40 g / L boric acid, 2 to 5 g / L fluorinated graphene, 15 to 20 g / L cerium oxide, 1 to 1.5 g / L sodium dodecyl sulfate, 0.2 to 0.5 g / L polyethylene glycol silane coupling agent, 1 to 2 g / L sodium saccharin, and 20 to 30 g / L sodium citrate.

2. The method for preparing a high-strength, high-wear-resistant titanium alloy rod according to claim 1, characterized in that: The method for preparing the boron-impregnated TC4 powder is as follows: TC4 powder and boron nitride are mixed and ball-milled; transferred to a graphite mold, heated to 1000-1100℃ under vacuum at a rate of 80-150℃ / min, and sintered by spark plasma for 5-8 min under a pressure of 30-40 MPa. After cooling in the furnace, the powder is crushed and ground to obtain the boron-impregnated TC4 powder.

3. The method for preparing a high-strength, high-wear-resistant titanium alloy rod according to claim 1, characterized in that: The roughening is laser texturing; during the cold spraying process, the laser-textured substrate is preheated to 150~200℃; cold spraying is performed using nitrogen as the gas, spraying temperature of 600~700℃, spraying pressure of 3~4MPa, spraying distance of 20~30mm, and powder feeding rate of 20~25g / min. The heat treatment process parameters are as follows: heat treatment at 700~720℃ for 20~30 minutes, air cooling, and then annealing at 400~500℃ for 1~2 hours.

4. The method for preparing a high-strength, high-wear-resistant titanium alloy rod according to claim 1, characterized in that: During the laser post-processing, under an argon atmosphere, the laser power is 10-30W, the pulse width is <10 picoseconds, the repetition rate is 100-500kHz, the scanning speed is 1000-3000mm / s, the spot diameter is 30-50μm, and the energy density is 0.5-1.2J / cm². 2 .

5. The method for preparing a high-strength, high-wear-resistant titanium alloy rod according to claim 1, characterized in that: The titanium rod is a TC4 type titanium rod.

6. The high-strength, high-wear-resistant titanium alloy rod prepared by the method for preparing a high-strength, high-wear-resistant titanium alloy rod according to any one of claims 1 to 5.

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