A low-cost method for preparing nano in-situ particle reinforced titanium alloy wear-resistant coating

Abstract

The present invention discloses a method for preparing a low-cost nano-in-situ particle-reinforced titanium alloy wear-resistant coating, which solves the problem of poor wear resistance of titanium alloy in the prior art. The preparation steps of the coating preparation method are as follows: (1) using a planetary fast grinder to prepare Al-Si-based multi-element alloy powder; (2) using a laser deposition device to deposit an Al-Si-based multi-element alloy wear-resistant coating on the surface of the titanium alloy. During the deposition process, circulating gas is used for cooling to increase the cooling rate of the molten coating and ensure the generation of nano-in-situ particle-reinforced phase in the coating; (3) using machining technology to cut off excess coating on the surface of the laser-deposited wear-resistant coating, and the remaining wear-resistant coating thickness is 0.3-0.5 mm from the titanium alloy substrate; (4) using thinning and grinding technology to further thin and grind the remaining wear-resistant coating until the coating thickness reaches 4-20 μm; (5) according to the above preparation steps, a low-cost nano-in-situ particle-reinforced titanium alloy wear-resistant coating can be obtained, the coating contains a large amount of nano-in-situ particle-reinforced phase, and the coating has high hardness and good wear resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium alloy wear-resistant coating preparation, and specifically relates to a low-cost nano in-situ particle reinforced titanium alloy wear-resistant coating preparation method. Background Art

[0002] Titanium and titanium alloys are widely used in aerospace, aviation, petroleum, chemical industry, etc. due to their excellent comprehensive properties. However, titanium alloys have relatively poor wear resistance due to their large friction coefficient, so the application of titanium alloys under friction and wear conditions is severely limited. Therefore, titanium alloy wear-resistant coatings and their preparation technology have become one of the research hotspots in the field of titanium alloy surface strengthening, and are technical problems that have been longed for but not yet well solved in this field. Many researchers have prepared various titanium alloy wear-resistant coatings by particle reinforcement, gradient coating, etc., and these wear-resistant coatings can significantly improve the wear resistance of titanium alloys. Particle-reinforced titanium alloy wear-resistant coatings are usually prepared by adding hard particle phases to the titanium alloy matrix or in-situ hard particle reinforcement phases in the coating preparation, thereby improving the wear resistance of the titanium alloy surface. The size of the hard particle reinforcement phase has a great influence on the toughness and wear resistance of the titanium alloy wear-resistant coating. The smaller the size, the better the wear resistance of the alloy. However, when obtaining the size of the hard particle phase, special materials or complex preparation processes are often required to achieve, so the preparation cost is relatively high. Based on this, the present invention proposes a low-cost nano in-situ particle-reinforced titanium alloy wear-resistant coating preparation method. Summary of the invention

[0003] The purpose of the present invention is to provide a low-cost nano-in-situ particle-reinforced titanium alloy wear-resistant coating preparation method to solve the problem of poor wear resistance of titanium alloy in the prior art. The preparation steps of the coating preparation method are as follows: (1) using a planetary fast grinder to prepare Al-Si based multi-element alloy powder; (2) using a laser deposition device to deposit an Al-Si based multi-element alloy wear-resistant coating on the surface of the titanium alloy. During the deposition process, circulating gas is used for cooling to increase the cooling rate of the molten coating and ensure the generation of nano-in-situ particle-reinforced phase in the coating; (3) using machining technology to cut off excess coating on the surface of the laser deposited wear-resistant coating, and the remaining wear-resistant coating thickness is 0.3-0.5 mm from the titanium alloy substrate; (4) using thinning and grinding technology to further thin and grind the remaining wear-resistant coating until the coating thickness reaches 4-20 μm; (5) according to the above preparation steps, a low-cost nano-in-situ particle-reinforced titanium alloy wear-resistant coating can be obtained, the coating contains a large amount of nano-in-situ particle-reinforced phase, and the coating has high hardness and good wear resistance.

[0004] Another object of the present invention is to provide a low-cost method for preparing nano in-situ particle reinforced titanium alloy wear-resistant coating, which adopts laser deposition preparation technology and has the characteristics of simple process, low cost, wide applicability, etc.

[0005] The technical solution of the present invention is:

[0006] A method for preparing a low-cost nano-in-situ particle-reinforced titanium alloy wear-resistant coating, the preparation steps of which are as follows: using a planetary fast grinder to prepare Al-Si-based multi-element alloy powder; using a laser deposition device to deposit an Al-Si-based multi-element alloy wear-resistant coating on the surface of the titanium alloy, the coating thickness is 1-3 mm. During the deposition process, circulating gas is used for cooling to increase the cooling rate of the molten coating and ensure the generation of nano-in-situ particle-reinforced phases in the coating; using machining technology to cut off excess coating on the surface of the laser-deposited wear-resistant coating, the remaining wear-resistant coating thickness is 0.3-0.5 mm from the titanium alloy substrate; using thinning and grinding technology to further thin and grind the remaining wear-resistant coating until the coating thickness reaches 4-20 μm; according to the above preparation steps, a low-cost nano-in-situ particle-reinforced titanium alloy wear-resistant coating can be obtained, the coating contains a large amount of nano-in-situ particle-reinforced phases, and the coating has high hardness and good wear resistance.

[0007] The alloy powder raw material required by the preparation method is based on Al-Si components, and titanium alloy β-stabilizing elements (such as V, Nb, Mo, Cr, etc.) can be added for alloying to improve the wear resistance of the coating. The mass percentages of the powder components are: Al, 60-90%; Si, 5-35%; the rest is the sum of the β-stabilizing element content.

[0008] The structure of the coating prepared by the method contains nano in-situ Si phase, Ti-Al, Ti-Si and intermetallic compounds containing other alloy elements.

[0009] The microhardness of the coating prepared by this method is 550-750HV, and the friction and wear resistance is 5-20 times that of the substrate.

[0010] The coating prepared by this method has a low tendency to crack formation and no macro cracks were found.

[0011] The selected laser deposition power is 800-2000 W, the argon flow rate is 9-11 mL / min, the scanning speed is 0.8-2 mm / s, and the defocus is 6-8 cm.

[0012] High-purity argon is used as the cooling gas during the laser deposition process. The outer side of the end of the circulating gas is wrapped with a copper tube, and circulating water is passed into the copper tube for cooling.

[0013] The design idea of ​​the present invention is:

[0014] Laser deposition manufacturing technology combines laser cladding technology with rapid prototyping technology and is a new integrated manufacturing technology. This type of laser deposition technology has the characteristics of short processing cycle, high material utilization rate, and concentrated heat input. It has been widely used in titanium alloy surface modification. Since laser deposition technology has a high energy input, it is more suitable for the preparation of high melting point in-situ particle reinforcement phase. The generation of in-situ nanoparticle reinforcement phase can be achieved by selecting nanopowder materials and combining special process methods. However, nanopowder materials are prone to aggregation when mixed, which significantly reduces the effect of nanoparticles, and the preparation cost of nanopowder materials is high. The preparation method of the present invention does not require high particle size of powder raw materials, and both nanometer and micron levels are acceptable. Al-Si alloy has good wear resistance and low density. The maximum solid solubility of Al element in titanium alloy is about 7% (mass percentage), while the solid solubility of Si element in titanium alloy is very small, so the possibility of forming nanoparticle reinforcement phase between Al, Si and matrix Ti is high. β-stabilizing elements in titanium alloys (such as V, Nb, Cr, etc.) can promote the formation of β-phase, and β-phase has higher plasticity, which can ensure that the nano-in-situ particle reinforced titanium alloy wear-resistant coating has higher toughness and extend the service life of the coating.

[0015] The advantages and beneficial effects of the present invention are:

[0016] (1) The coating designed by the present invention can significantly improve the hardness and wear resistance of titanium alloy.

[0017] (2) The coating of the present invention adopts laser deposition technology and uses Al-Si based alloy powder to prepare low-cost nano in-situ particle reinforced wear-resistant coating on the surface of titanium alloy.

[0018] (3) The present invention has low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the morphology of the Al-13Si-2Nb coating.

[0020] Figure 2 Friction and wear properties of Al-13Si-2Nb coating. DETAILED DESCRIPTION

[0021] In a specific embodiment, a low-cost nano-in-situ particle-reinforced titanium alloy wear-resistant coating preparation method of the present invention uses Al-Si-based alloy powder, and titanium alloy β-stabilizing elements (such as V, Nb, Mo, Cr, etc.) can be added for alloying to improve the wear resistance of the coating. The mass percentages of the powder components are: Al, 60-90%; Si, 5-35%; the rest is the sum of the β-stabilizing element content. The powder is mixed using a planetary fast grinder, the mixing speed is 100r / min, and the mixing time is 150min. A 3000W fiber laser is used for laser deposition, the laser deposition power is 800-2000 W, the flow rate of argon is 9-11mL / min, the scanning speed is 0.8-2 mm / s, and the defocus is 6-8 cm. High-purity argon is used as the cooling gas in the laser deposition process, and the outer side of the end of the circulating gas is wrapped with a copper tube, and circulating water is passed into the copper tube for cooling.

[0022] The excess coating is cut off on the surface of the laser deposited wear-resistant coating by machining technology, and the thickness of the remaining wear-resistant coating is 0.3-0.5 mm from the titanium alloy substrate. The remaining wear-resistant coating is further thinned and ground by thinning and grinding technology until the coating thickness reaches 4-20 μm. According to the above preparation steps, a low-cost nano-in-situ particle-reinforced titanium alloy wear-resistant coating can be obtained. The coating contains a large amount of nano-in-situ particle reinforcement phase, and the coating has high hardness and good wear resistance.

[0023] The wear-resistant coating prepared by the preparation method contains nano-in-situ Si phase, Ti-Al, Ti-Si and intermetallic compounds containing other alloy elements in its structure. The microhardness of the coating prepared by the method is 550-750HV, and the friction and wear resistance is 5-20 times that of the substrate. The coating has a small tendency to form cracks and no cracks are found.

[0024] In the present invention, the laser deposition equipment is a 3000W fiber laser deposition equipment produced by Wuhan Ruifeng Optoelectronics Technology Co., Ltd.

[0025] In order to make the technical solutions and advantages of the present invention more clear, a detailed description will be given below in conjunction with specific embodiments.

[0026] Example 1

[0027] The Al-13Si-2Nb alloy powder was laser deposited on the surface of Ti6Al4V titanium alloy. The laser power was 900W, the argon flow rate was 10 mL / min, the scanning speed was 1 mm / s, the defocus was 7 cm, and high-purity circulating argon was used for cooling during the preparation to obtain a coating with a thickness of 1 mm. The excess coating was cut off on the surface of the laser deposited coating using wire cutting technology, and the remaining wear-resistant coating thickness was 0.4 mm from the titanium alloy substrate. The remaining wear-resistant coating was further thinned and ground using sandpaper and a grinder until the coating thickness reached 8μm, and the target low-cost nano in-situ particle-reinforced titanium alloy wear-resistant coating was prepared. According to the traditional metallographic preparation method, the organization was observed, and it was found that the organization of the coating contained nano in-situ Si phase, Ti-Al, Ti-Si and intermetallic compounds containing other alloy elements. No macro cracks were found in the coating, see the attached Figure 1 The performance test was carried out using a hardness tester and a friction and wear tester, and it was found that the microhardness of the coating was 580HV; the friction and wear resistance was about 10-15 times that of the substrate, see attached Figure 2 .

[0028] Example 2

[0029] The Al-15Si-15Nb alloy powder was laser deposited on the surface of Ti6Al4V titanium alloy. The laser power was 900W, the flow rate of argon was 10 mL / min, the scanning speed was 1 mm / s, the defocus was 7 cm, and high-purity circulating argon was used for cooling during the preparation to obtain a coating with a thickness of 1.5 mm. The excess coating was cut off on the surface of the laser deposited coating using wire cutting technology, and the remaining wear-resistant coating thickness was 0.35 mm from the titanium alloy substrate. The remaining wear-resistant coating was further thinned and ground using sandpaper and a grinder until the coating thickness reached about 15 μm, and the target low-cost nano in-situ particle-reinforced titanium alloy wear-resistant coating was prepared.

[0030] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A low-cost method for preparing nano in-situ particle reinforced titanium alloy wear-resistant coating, the preparation steps are as follows: The Al-Si based multi-element alloy powder was prepared by using a planetary rapid grinding machine; Laser deposition equipment is used to deposit Al-Si based multi-element alloy wear-resistant coating on the surface of titanium alloy; circulating gas is used for cooling during the deposition process to increase the cooling rate of the molten coating and ensure the formation of nano-in-situ particle reinforcement phase in the coating; The excess coating is cut off on the surface of the laser deposited wear-resistant coating by machining technology, and the thickness of the remaining wear-resistant coating is 0.3-0.5 mm from the titanium alloy substrate; Use thinning and grinding technology to further thin and grind the remaining wear-resistant coating until the coating thickness reaches 4-20 microns; According to the above preparation steps, a low-cost nano in-situ particle reinforced titanium alloy wear-resistant coating can be obtained; The structure of the coating prepared by this method contains nano-in-situ Si phase, Ti-Al phase and Ti-Si phase; The selected laser deposition power is 800-2000W, the flow rate of argon gas is 9-11mL / min, the scanning speed is 0.8-2mm / s, and the defocusing amount is 6-8cm.

2. The method for preparing a low-cost nano-in-situ particle-reinforced titanium alloy wear-resistant coating according to claim 1, characterized in that: The alloy powder raw material required by the method is based on Al-Si components, titanium alloy β-stabilizing elements are added, and alloying is performed to improve the wear resistance of the coating; the mass percentages of the powder components are: Al, 60-90%; Si, 5-35%; the rest is the sum of the β-stabilizing element content.

3. The method for preparing a low-cost nano-in-situ particle-reinforced titanium alloy wear-resistant coating according to claim 1, characterized in that: The microhardness of the coating prepared by this method is 550-750HV, and the friction and wear resistance is 5-20 times that of the substrate.

4. The method for preparing a low-cost nano-in-situ particle-reinforced titanium alloy wear-resistant coating according to claim 1, characterized in that: High-purity argon is used as the cooling gas during the laser deposition process. The outer side of the end of the circulating gas is wrapped with a copper tube, and circulating water is passed into the copper tube for cooling.

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