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

Abstract

The invention discloses a high-strength and high-wear-resistance titanium alloy bar and a preparation method thereof, and relates to the technical field of titanium alloy surface treatment. The method comprises the steps that 1, a titanium rod serves as a base material and is subjected to roughening, cold spraying of alloy composite powder and heat treatment in sequence, and a transition layer is formed; a titanium alloy bar A is obtained; 2, the titanium alloy bar A is polished, deoiled and subjected to acid pickling, then a nickel-graphene-cerium oxide layer is electroplated, then laser aftertreatment is conducted, and a wear-resistant layer is formed; the high-strength and high-wear-resistance titanium alloy bar is obtained; the alloy composite powder comprises one or more of TC4 powder, boriding TC4 powder and CuNiIn powder. According to the method, the high-strength TC4 type titanium rod serves as a base body, the surface of the high-strength TC4 type titanium rod is further strengthened, the transition layer is formed through cold spraying, then the abrasion-resistant layer is effectively formed through the gradient electrodeposition technology, and finally the surface hardness is effectively improved through laser strengthening.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of titanium alloy surface treatment, and particularly relates to a high-strength and high-wear-resistance titanium alloy rod and a preparation method thereof. BACKGROUND

[0002] Titanium alloy rods have a wide range of applications in the technical fields of aerospace, medical devices and the like due to excellent specific strength and corrosion resistance. Among them, Ti-6Al-4V (TC4 type) is an alpha + beta type alloy with medium hardness, and has low surface hardness, poor wear resistance and high friction coefficient, which greatly limits the reliability and service life thereof under working conditions of bearing friction and wear.

[0003] At present, the surface performance improvement of titanium alloy rods generally includes chemical heat treatment, vapor deposition, laser cladding, electrodeposition and the like. Among them, chemical heat treatment processes such as carburizing and nitriding have the defect of high treatment temperature affecting the microstructure of the base material. Vapor deposition processes such as magnetron sputtering can obtain a coating with excellent performance, but the equipment cost is high and the industrialization is not widely applicable. The laser cladding method has problems such as causing lattice distortion and large residual stress. Compared with the above methods, the electrodeposition technology has the advantages of small heat effect on the base material, simple operation and wide application range, and is more widely used in metal surface modification.

[0004] In the prior art, the nickel-based plating layer has the properties of compact structure and good wear resistance, but the following defects still exist: first, the bonding strength between the electroplated layer and the titanium alloy base material is insufficient, which leads to cracks and peeling under heavy load or impact working 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 plating layer, and reducing the content of particles will reduce the surface wear resistance.

[0005] In summary, it is of great significance to solve the above problems and prepare a high-strength and high-wear-resistance titanium alloy rod. SUMMARY

[0006] The present application aims to provide a high-strength and high-wear-resistance titanium alloy rod and a preparation method thereof to solve the problems raised in the background.

[0007] A preparation method of a high-strength and high-wear-resistance titanium alloy rod, comprising the following steps: Step 1: taking a titanium rod as a base material, sequentially performing roughening, cold spraying of alloy composite powder and heat treatment to form a transition layer; obtaining a titanium alloy rod A; Step 2: polishing and removing oil from the titanium alloy rod A, acid pickling, electroplating a nickel-graphene-cerium oxide layer, and then laser post-treatment to form a wear-resistant layer; obtaining a high-strength and high-wear-resistance titanium alloy rod; The alloy composite powder comprises one or more of TC4 powder, boronized TC4 powder and CuNiIn powder.

[0008] More preferably, 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.

[0009] In the scheme, TC4 powder, boronized TC4 powder and CuNiIn powder in a specific ratio are used as the transition layer, wherein the TC4 powder is the main powder and is homologous to the base material, which can better adhere to the roughened surface of the base material and form a continuous phase with the coating; the boronized TC4 powder contains hard TiB phase, which produces dispersion strengthening effect on the transition layer; and the introduced CuNiIn powder is relatively soft, which acts as a binder and lubricant for the boronized TC4 powder and helps to improve the density of the transition layer.

[0010] More preferably, the preparation method of the boronized TC4 powder comprises: mixing TC4 powder and boron nitride and ball milling; transferring to a graphite mold, heating to 1000-1100℃ at a rate of 80-150℃ / min under vacuum, and spark plasma sintering for 5-8 min under a pressure of 30-40 MPa, and then cooling in the furnace, crushing and grinding to obtain the boronized TC4 powder.

[0011] More preferably, the roughening is laser roughening, and the process parameters of the laser roughening are as follows: grid scanning under an argon atmosphere, laser power of 50-100 W, scanning speed of 800-1200 mm / s, and line spacing of 0.1-0.15 mm. In the cold spraying process, the laser-roughened base material is preheated to 150-200℃; nitrogen is used as the gas type, the spraying temperature is 600-700℃, the spraying pressure is 3-4 MPa, the spraying distance is 20-30 mm, and the powder feeding rate is 20-25 g / min. The process parameters of the heat treatment are as follows: holding at 700-720℃ for 20-30 min, air cooling, and then annealing at 400-500℃ for 1-2 h.

[0012] In the process, laser roughening can promote interfacial bonding; after heat treatment, thermal diffusion bonding occurs between the TC4 powder, the boronized TC4 powder and the CuNiIn powder, which effectively improves the bonding strength of the transition layer, reduces the porosity in cold spraying and improves the density; and the internal stress generated in cold spraying is released. In the process, the hard TiB whiskers contained in the boronized TC4 powder are strengthened in combination with the soft CuNiIn, forming a stable and dense transition layer; and the subsequent electroplating is promoted. Due to the presence of CuNiIn powder, the nickel element can promote the deposition of the subsequent nickel-graphene-cerium oxide layer, improve the electroplating bonding force and reduce the stress.

[0013] More preferably, in the process of pickling, the pickling is carried out in turn by using a mixed solution of hydrofluoric acid and nitric acid and a mixed solution of phosphonic acid; the raw materials of the mixed solution of hydrofluoric acid include 40-50 mL / L of hydrofluoric acid, 100-120 mL / L of nitric acid, 80-100 mL / L of hydrogen peroxide, and the rest is deionized water; The mixed solution of phosphonic acid has a pH of 3-3.5, and the raw materials thereof include 80-120 mL / L of aminotri(methylphosphonic acid), 40-60 g / L of citric acid, 20-40 mL / L of hydrogen peroxide, 1-3 g / L of ammonium fluoride, and the rest is water.

[0014] In the process of pickling, the mixed solution of hydrofluoric acid is used at room temperature for 30-60 seconds, then washed with water and dried with nitrogen; then the mixed solution of phosphonic acid is used for pickling at 45-55°C for 1-5 minutes, then washed with water and dried with nitrogen.

[0015] In the process, in order to improve the performance of the electroplated layer, two kinds of acid mixed solutions, a mixed solution of hydrofluoric acid and nitric acid, are used for pre-activation to form a relatively rough surface, and then the surface roughness is refined in the mixed solution of phosphonic acid to form uniform high-density nano pits, which promotes subsequent electroplating. At the same time, the aminotri(methylphosphonic acid) and citric acid contained therein have strong complexation and can completely chelate and remove the trace metal ion pollutants remaining in the first step to form a uniform surface. In addition, the aminotri(methylphosphonic acid) can prevent secondary oxidation during the period from processing to electroplating, and can also perfectly infiltrate the subsequent electroplating solution and provide abundant nickel ion nucleation sites.

[0016] More preferably, in the process of electroplating the nickel-graphene- cerium oxide layer, the electroplating solution has a pH of 3.8-4.5 and includes the following raw materials: 300-320 g / L of nickel sulfate, 40-50 g / L of nickel chloride, 35-40 g / L of boric acid, 2-5 g / L of fluorinated graphene, 15-20 g / L of cerium oxide, 1-1.5 g / L of sodium dodecyl sulfate, 0.2-0.5 g / L of polyethylene glycol silane coupling agent, 1-2 g / L of sodium saccharin, and 20-30 g / L of sodium citrate.

[0017] In the 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. The fluorinated graphene is in a sheet shape and has solid lubrication to reduce the friction coefficient. The cerium oxide is in a particle shape and has a hard shape to disperse and strengthen and inhibit wear. A composite wear-resistant network is formed. In order to improve the dispersibility, a polyethylene glycol silane coupling agent is used as a dispersant to improve the dispersibility of the wear-resistant particles.

[0018] Compared with conventional graphene oxide, the use of fluorinated graphene has better stability and dispersibility in the plating solution than graphene oxide, and the fluorine atoms can form a stronger interface with nickel ions to have better interlayer lubricity.

[0019] More preferably, the electroplating process is as follows: the temperature of the electroplating solution is 40-45℃, the anode is an electrolytic nickel plate, and the electroplating distance is 30-35mm; first, activate for 30-60 seconds at a cathode current density of 0.5-1A / dm2; then, electrodeposition for 5-10 minutes at a high pulse current of 5-6A / dm2 and a duty cycle of 30%; electrodeposition for 20-40 minutes at a medium pulse current of 3-4A / dm2 and a duty cycle of 40%; electrodeposition for 10-15 minutes at a low direct current density of 1-2A / dm2; and ultrasonic auxiliary dispersion at a frequency of 40-50 kHz is provided during the entire process.

[0020] In the scheme, since two kinds of wear-resistant particles are used, a gradient electroplating process is used in the scheme to improve the compactness and wear resistance of the plating layer; first, surface activation to improve surface properties; then, high pulse to lay the foundation, promote co-deposition of wear-resistant particles, and form a compact composite bottom layer with firm interface bonding; then, use medium pulse to thicken, ensure uniform dispersion of wear-resistant particles while achieving uniform thickening, and improve the hardness and wear resistance of the plating layer; finally, low direct current deposition makes the nickel electrocrystallization process more gentle and orderly, reduces internal stress, and reduces the tendency of the plating layer to crack; thus forming a gradient plating layer to improve the adhesion and wear resistance of the plating layer.

[0021] More preferably, in the process of laser post-treatment, the laser power is 10-30W, the pulse width is <10 picoseconds, the repetition frequency 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 / cm 2 .

[0022] Finally, the surface is subjected to laser strengthening treatment, the surface layer is rapidly remelted, thereby densified and phase-transformed, the surface layer grains are refined, micro defects are eliminated, and the surface properties are improved; at the same time, the heat zone of the laser treatment is extremely shallow, and the overall bonding strength of the plating layer and the substrate properties are not damaged.

[0023] More preferably, the titanium rod is a TC4 type titanium rod.

[0024] The TC4 type titanium rod is a high-strength titanium rod, and the preparation process is as follows: TC4 type titanium ingot is open-die forged at 980-1150℃ (forged above the beta phase transition point), intermediate forged at 950-980℃ (in the alpha+beta two-phase region or near the beta region), finish forged at 750-950℃ (in the lower part of the alpha+beta two-phase region), rolled, annealed at 650-800℃ (below the beta phase transition point), and air or furnace cooled; after solid solution at 870-890℃ and rapid cooling, aging at 500-580℃; turning or grinding; removing the surface oxide layer and embedded iron contamination in a hydrofluoric acid-nitric acid mixed solution, and improving the surface state by sandblasting or shot blasting; to obtain a TC4 type titanium rod.

[0025] More preferably, the high-strength and high-wear-resistance titanium alloy rod is prepared by the preparation method of the high-strength and high-wear-resistance titanium alloy rod.

[0026] Compared with the prior art, the application has the beneficial effects that: in the application, a high-strength TC4 type titanium rod is used as a base body, the surface of the base body is further strengthened, a transition layer is formed by cold spraying, then a gradient electrodeposition process is used to effectively form a wear-resistant layer, and finally laser strengthening is used to effectively improve the surface hardness.

[0027] The use of the cold-sprayed transition layer has the following effects: compared with nitriding or direct laser cladding, the method does not affect the base body strength of the TC4 type titanium rod; compared with the previous nickel plating layer, the method can effectively buffer stress and improve the bonding strength by setting the transition layer; and the cold spraying forms a rough structure, which can promote the interface bonding force of the plating layer.

[0028] The introduction of the specific pickling solution effectively improves the nucleation of the nickel layer and the adhesion of the electroplated layer, and cooperates with the transition layer to improve the bonding strength of the plating layer and inhibit crack generation and peeling.

[0029] The gradient electrodeposition process is used in the same electroplating solution containing fluorinated graphene and cerium dioxide to deposit a continuous gradient structure and effectively form a high-hardness surface. The gradient deposition process effectively relieves stress concentration and avoids brittle peeling of the high-hardness outer layer. At the same time, laser strengthening of the outermost layer densifies the outer layer quickly, eliminates micro defects, and effectively improves the surface hardness.

[0030] Therefore, without sacrificing the base body performance, the high-strength and high-wear-resistance titanium alloy rod is achieved, which effectively improves the surface wear resistance and bonding force. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the application will be described below in a clear and complete manner. Obviously, the described embodiments are only some of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the application.

[0032] It should be noted that the following parts are by weight, and there is no special restriction on the purchase manufacturers of all raw materials involved in the application, which exemplarily includes: in the following embodiments, the fluorinated graphene sheet is 0.4-5 mu m, and the cerium oxide is 40-60 nm; the CAS number of the polyethylene glycol silane coupling agent is 98358-37-3, and the graphene oxide is 0.5-5 mu m; all the above and other unmentioned raw materials are commercially available.

[0033] Embodiment 1: A method for preparing a high-strength and high-wear-resistance titanium alloy rod, comprising the following steps: Preparation: TC4 titanium ingot is open-die forged at 1100℃, intermediate forged at 950℃, finish forged at 850℃, rolled, annealed at 750℃, air or furnace cooled; solution treated at 880℃ and quenched, aged at 550℃; turned or ground; surface oxide layer and embedded iron contamination are removed in a mixture of hydrofluoric acid and nitric acid, sandblasting or shot blasting is used to improve the surface state; a high-strength TC4 titanium rod is obtained; Preparation of boronized TC4 powder: TC4 powder and boron nitride are mixed and ball milled at a ratio of 5:1; transferred to a graphite mold, heated to 1050℃ at a rate of 100℃ / min under vacuum, and spark plasma sintered at a pressure of 35Mpa for 5min, cooled in the furnace, broken and ground to obtain boronized TC4 powder; the TC4 powder is homologous to the TC4 titanium ingot, and the addition amount of boron nitride is 0.15wt%; Step 1: The titanium rod is laser textured, and in the process: grid scanning under argon atmosphere, laser power is 60W, scanning speed is 1000mm / s, line spacing is 0.1mm; then the surface of the titanium rod is cold sprayed with alloy composite powder, and in the process: the laser textured substrate is preheated to 200℃; cold spraying is carried out with nitrogen as the gas type, spraying temperature is 680℃, spraying pressure is 3MPa, spraying distance is 25mm, and powder feeding rate is 20g / min; then heat treatment is carried out, and in the process: heat preservation at 720℃ for 30min, air cooling, and then annealing at 450℃ for 2h; in this way, a transition layer is formed; a titanium alloy rod A is obtained; Step 2: The surface of the titanium alloy rod A is mechanically polished with 500 mesh, 1000 mesh and 1400 mesh metallographic paper in turn, and then alkali washed; then it is first immersed in a mixture of hydrofluoric acid for 60 seconds at room temperature, washed with water and dried with nitrogen; then it is pickled in a phosphonic acid mixture at 50℃ for 3min, washed with water and dried with nitrogen; it is placed in an electroplating solution, with the temperature of the electroplating solution being 45℃, the anode being an electrolytic nickel plate, and the electroplating distance being 30mm; first activated at a cathode current density of 1A / dm² for 30 seconds; then electrodeposited at a high pulse current of 5A / dm² and a duty cycle of 30% for 8min; electrodeposited at a medium pulse current of 4A / dm² and a duty cycle of 40% for 30min; electrodeposited at a low direct current density of 1.5A / dm² for 10min; in the whole process, ultrasonic assisted dispersion with a frequency of 50kHz is provided; then laser post-processing is carried out, and in the process: argon atmosphere, laser power is 20W, pulse width is <10 picoseconds, repetition frequency is 200kHz, scanning speed is 2000mm / s, spot diameter is 30μm, energy density is 1J / cm 2 ; in this way, a wear-resistant layer is formed; a high-strength and high-wear-resistance titanium alloy rod is obtained; In this embodiment, the alloy composite powder is composed of TC4 powder, boronized TC4 powder and CuNiIn powder with a mass ratio of 60:22:18; The raw materials of the hydrofluoric acid mixture solution include 50 mL / L hydrofluoric acid, 120 mL / L nitric acid, 100 mL / L hydrogen peroxide, and the rest is deionized water; The phosphonic acid mixture solution has a pH of 3.4, and its raw materials include 120 mL / L aminotri(methylphosphine) acid, 50 g / L citric acid, 30 mL / L hydrogen peroxide, 2 g / L ammonium hydrogen fluoride, and the rest is water; During the process of electroplating the 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.

[0034] Embodiment 2: A method for preparing a high-strength and high-wear-resistance titanium alloy rod, comprising the following steps: Early preparation: TC4 titanium ingot is open-die forged at 1100℃, intermediate forged at 950℃, finish forged at 850℃, rolled, annealed at 750℃, and air or furnace cooled; after solid solution at 880℃ and rapid cooling, aging at 550℃; turning or grinding; removing the surface oxide layer and embedded iron contamination in the hydrofluoric acid-nitric acid mixture solution, and improving the surface state by sandblasting or shot blasting; obtaining a high-strength TC4 titanium rod; Preparation of boronized TC4 powder: TC4 powder and boron nitride are mixed and ball milled at a ratio of 5:1; transferred to a graphite mold, heated to 1050℃ at 100℃ / min under vacuum, and spark plasma sintered at a pressure of 35Mpa for 5min, and then cooled in the furnace, broken and ground to obtain boronized TC4 powder; the TC4 powder is homologous to the TC4 titanium ingot, and the addition amount of boron nitride is 0.15wt%; Step 1: The titanium rod is laser textured in an argon atmosphere with a grid scan, a laser power of 60W, a scanning speed of 1000mm / s, and a line spacing of 0.1mm; then the surface of the titanium rod is cold sprayed with alloy composite powder, in which the laser textured substrate is preheated to 200℃, the gas type is nitrogen, the spraying temperature is 680℃, the spraying pressure is 3MPa, the spraying distance is 25mm, and the powder feeding rate is 20g / min; then heat treatment is performed, in which the temperature is kept at 720℃ for 30min, air cooling is performed, and then annealing is performed at 450℃ for 2h; in this way, a transition layer is formed; and a titanium alloy rod A is obtained; Step 2: The surface of the titanium alloy bar A is mechanically polished with 500 mesh, 1000 mesh and 1400 mesh metallographic paper in sequence, and then is alkali washed; 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 pickled in a phosphonic acid mixture at 50℃ for 3 minutes, washed with water and dried with nitrogen; it is placed in an electroplating solution, with the electroplating solution temperature being 45℃, the anode being an electrolytic nickel plate and the electroplating distance being 30 mm; it is first activated for 60 seconds with a cathode current density of 0.5 A / dm2; then it is electrodeposited for 5 min with a high pulse current of 5 A / dm2 and a duty cycle of 30%; it is electrodeposited for 40 min with a medium pulse current of 3 A / dm2 and a duty cycle of 40%; it is electrodeposited for 10 min with a low direct current density of 2 A / dm2; in the overall process, ultrasonic auxiliary dispersion with a frequency of 50 kHz is provided; then laser post-processing is performed, in which: under an argon atmosphere, the laser power is 20 W, the pulse width is <10 picoseconds, the repetition frequency is 200 kHz, the scanning speed is 2000 mm / s, the spot diameter is 30 μm and the energy density is 1 J / cm2 2 ; in this way, a wear-resistant layer is formed; a high-strength high-wear-resistant titanium alloy bar is obtained; 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; The raw materials of the hydrofluoric acid mixture include: 50 mL / L hydrofluoric acid, 120 mL / L nitric acid, 100 mL / L hydrogen peroxide, and the rest is deionized water; The phosphonic acid mixture has a pH of 3.4, and its raw materials include: 120 mL / L aminotri(methylphosphine) acid, 50 g / L citric acid, 30 mL / L hydrogen peroxide, 2 g / L ammonium hydrogen fluoride, and the rest is water; In the process of electroplating the 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.

[0035] Embodiment 3: A method for preparing a high-strength high-wear-resistant titanium alloy bar, comprising the following steps: Preparation: TC4 titanium ingots are open-die forged at 1100℃, intermediate-forged at 950℃, finish-forged at 850℃, rolled, annealed at 750℃, and air-cooled or furnace-cooled; solution-treated at 880℃ and then quickly cooled, and aged at 550℃; turned or ground; the surface oxide layer and embedded iron contamination are removed in a hydrofluoric acid-nitric acid mixture, and the surface state is improved by sandblasting or shot blasting; a high-strength TC4 titanium bar is obtained; Preparation of boronized TC4 powder: TC4 powder and boron nitride were mixed and ball milled with a ball milling ratio of 5:1; then transferred into a graphite mold, heated to 1050℃ at a rate of 100℃ / min under vacuum, and spark plasma sintered for 5 min under a pressure of 35 MPa, and then cooled in the furnace, broken and ground to obtain boronized TC4 powder; the TC4 powder is homologous to TC4 titanium ingot, and the addition amount of boron nitride is 0.15wt%; Step 1: take a titanium bar as a base material, laser texturize it, in the process: grid scanning under argon atmosphere, laser power is 60W, scanning speed is 1000mm / s, line spacing is 0.1mm; then cold spray alloy composite powder on its surface, in the process: preheat the laser textured substrate to 200℃; cold spray with nitrogen as the gas type, spray temperature is 680℃, spray pressure is 3MPa, spray distance is 25mm, powder feeding rate is 20g / min; then heat treatment, in the process: heat preservation at 720℃ for 30 minutes, air cooling, then annealing at 450℃ for 2 hours; in this way, a transition layer is formed; titanium alloy bar A is obtained; Step 2: mechanically polish the surface of titanium alloy bar A with 500 mesh, 1000 mesh and 1400 mesh metallographic paper in turn, and then alkali wash; then immerse it in a mixed solution of hydrofluoric acid at room temperature for 60 seconds, wash with water and dry with nitrogen; then acid wash in a phosphonic acid mixed solution at 50℃ for 3 minutes, wash with water and dry with nitrogen; place it in an electroplating solution, with the temperature of the electroplating solution being 45℃, the anode being an electrolytic nickel plate, and the electroplating distance being 30mm; first activate it with a cathode current density of 1A / dm² for 30 seconds; then electrodeposition for 5min with a high pulse current of 6A / dm² and a duty cycle of 30%; then electrodeposition for 20min with a medium pulse current of 4A / dm² and a duty cycle of 40%; then electrodeposition for 10min with a low direct current density of 1A / dm²; in the whole process, ultrasonic assisted dispersion with a frequency of 50kHz is provided; then laser post-processing, in the process: argon atmosphere, laser power is 20W, pulse width <10 picoseconds, repetition frequency is 200kHz, scanning speed is 2000mm / s, spot diameter is 30μm, energy density is 1J / cm 2 ; in this way, a wear-resistant layer is formed; a high-strength high-wear-resistant titanium alloy bar is obtained; In this embodiment, the alloy composite powder is composed of TC4 powder, boronized TC4 powder and CuNiIn powder with a mass ratio of 65:20:15; The raw materials of the mixed solution of hydrofluoric acid include: 50mL / L hydrofluoric acid, 120mL / L nitric acid, 100mL / L hydrogen peroxide, and the rest is deionized water; The pH of the phosphonic acid mixed solution is 3.4, and its raw materials include: 120mL / L aminotriisopropyl phosphonic acid, 50g / L citric acid, 30mL / L hydrogen peroxide, 2g / L ammonium hydrogen fluoride, and the rest is water; In the process of electroplating the nickel-graphene- cerium oxide layer, the electroplating solution has a pH of 4.2 and contains 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.

[0036] Comparative Example 1: In the cold spraying process, no boronized TC4 powder is introduced, and the rest is the same as in Example 1; the difference lies in the following steps: Step 1: A titanium rod is used as the base material, which is laser textured in an argon atmosphere with a grid scan, a laser power of 60 W, a scanning speed of 1000 mm / s, and a line spacing of 0.1 mm. Then, the surface of the laser textured base material is cold sprayed with an alloy composite powder, in which the laser textured base material is preheated to 200°C, the gas type is nitrogen, the spraying temperature is 600°C, the spraying pressure is 3 MPa, the spraying distance is 25 mm, and the powder feeding rate is 20 g / min. Then, heat treatment is performed at 650°C for 30 minutes, air cooling, and then annealing at 450°C for 2 hours. In this way, a transition layer is formed. A titanium alloy rod A is obtained. In this example, the alloy composite powder is composed of TC4 powder and CuNiIn powder in a mass ratio of 80:20.

[0037] Comparative Example 2: In the cold spraying process, an excess amount of boronized TC4 powder is introduced, and the rest is the same as in Example 1; the difference lies in the following steps: In this example, the alloy composite powder is composed of TC4 powder, boronized TC4 powder, and CuNiIn powder in a mass ratio of 52:30:18.

[0038] Comparative Example 3: In the electroplating process, a single process is used for electroplating, and the rest is the same as in Example 1; the difference lies in the following steps: Step 2: The surface of the titanium alloy rod A is mechanically polished with 500-mesh, 1000-mesh, and 1400-mesh metallographic paper in sequence, and then alkali washed. 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 placed in an electroplating solution with an electroplating solution temperature of 45°C, an anode of an electrolytic nickel plate, and an electroplating distance of 30 mm. A medium pulse current of 4 A / dm² and a duty cycle of 40% are used for electrodeposition for 48 minutes. An ultrasonic wave with a frequency of 50 kHz is used for auxiliary dispersion during the whole process. Then, laser post-processing is performed in an argon atmosphere with a laser power of 20 W, a pulse width of <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; in this way, a wear-resistant layer is formed; and a titanium alloy rod with high strength and high wear resistance is obtained.

[0039] Comparative Example 4: In the electroplating process, the graphene fluoride is adjusted to graphene oxide, and the rest is the same as in Example 1; the difference lies in the following steps: In the process of electroplating the nickel-graphene oxide-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.

[0040] Comparative Example 5: A single acid treatment is used, and the rest is the same as in Example 1; the difference lies in the following steps: Step 2: The surface of the titanium alloy rod A is mechanically polished with 500-mesh, 1000-mesh, and 1400-mesh metallographic paper in sequence, and is subjected to alkaline cleaning; then it is immersed in a hydrofluoric acid mixture at room temperature for 3 minutes, washed with water, and dried with nitrogen; and then it is placed in an electroplating solution, with an electroplating solution temperature of 45°C, an anode of an electrolytic nickel plate, and an electroplating distance of 30 mm; first, it is activated at a cathode current density of 1 A / dm² for 30 seconds; then, it is electrodeposited at a high pulse current of 5 A / dm² and a duty cycle of 30% for 8 minutes; then, it is electrodeposited at a medium pulse current of 4 A / dm² and a duty cycle of 40% for 30 minutes; and then, it is electrodeposited at a low direct current density of 1.5 A / dm² for 10 minutes; during the entire process, ultrasonic auxiliary dispersion with a frequency of 50 kHz is provided; then, laser post-processing is performed, with the following process parameters: an argon atmosphere, a laser power of 20 W, a pulse width of <10 picoseconds, a repetition frequency of 200 kHz, a scanning speed of 2000 mm / s, a spot diameter of 30 μm, an energy density of 1 J / cm 2 ; in this way, a wear-resistant layer is formed; and a titanium alloy rod with high strength and high wear resistance is obtained.

[0041] Performance Test 1: Basic tests are performed on the TC4 titanium rod, including (1) determination of hydrogen content according to GB / T4698.15-2011; (2) determination of room temperature tensile properties according to GB / T228.1-2010; and (3) determination of high-magnification microstructure according to GB / T5168-2020; the obtained data are shown in the following table:

[0042] Conclusion: It is shown that the titanium rod has high strength and high toughness, and is suitable for use in fields with high requirements for mechanical properties and reliability; at the same time, it is suitable for further surface strengthening treatment to improve surface hardness and wear resistance, thereby improving its high wear resistance and expanding its application in working conditions involving friction and wear.

[0043] Performance test 2: (1) using a microhardness tester, load 5N, loading time 15 seconds, measuring microhardness; (2) using a pin-on-disk friction and wear test, with a load of 10N, a temperature of 600°C, a rotational speed of 560r / min, a friction radius of 3mm, a test time of 60 minutes, measuring the mass loss before and after, measuring the wear amount; (3) using a scratch tester, with a loading speed of 10N / min, a diamond indenter, measuring the critical load at which peeling occurs; the data obtained are shown in the following table:

[0044] Conclusion: From the data in the above table, it can be seen that a titanium alloy bar with high wear resistance is prepared; the data of Comparative Examples 1-2 shows that boronized TC4 powder introduction and excessive boronized 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 force; the data of Comparative Example 4 shows that adjusting the graphene fluoride to graphene oxide causes a slight decrease in related performance; the data of Comparative Example 5 shows that a single acid treatment affects the bonding performance.

[0045] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application 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 replacements to some technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

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 includes one or more of TC4 powder, boronized TC4 powder, and CuNiIn powder.

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

3. The method for preparing a high-strength, high-wear-resistant titanium alloy rod according to claim 2, 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.

4. 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.

5. The method for preparing a high-strength, high-wear-resistant titanium alloy rod according to claim 1, characterized in that: During the pickling process, a mixture of hydrofluoric acid and nitric acid and a mixture of phosphonic acid are used sequentially for pickling. 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.

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

7. The method for preparing a high-strength, high-wear-resistant titanium alloy rod according to claim 6, characterized in that: 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 and duty cycle of 30% are used for electrodeposition for 5~10 minutes; medium pulse current of 3~4A / dm² and duty cycle of 40% are 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 process, ultrasonic dispersion with a frequency of 40~50 kHz is used.

8. 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 .

9. 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.

10. 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 9.

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