摘要
目的改善钛合金零部件之间因相对滑动造成的磨损,提升钛合金零部件的使用寿命。方法采用超音速火焰喷涂(HVOF)方法在TC4钛合金表面上制备Cr_(3)C_(2)-NiCr、Ni50和NiCr涂层。采用扫描电子显微镜(SEM)、显微硬度计等分析涂层的显微结构及力学性能,采用多功能摩擦磨损试验机及白光共焦三维形貌仪测试和分析不同涂层与TC4钛合金在干摩擦条件下的摩擦学性能。结果Ni50和NiCr涂层的硬度分别为680HV0.3和438HV0.3,低于Cr_(3)C_(2)-NiCr涂层硬度1120HV0.3。在高载荷作用下,由于Ni50和NiCr涂层的硬度较低,导致其颗粒界面出现裂纹,断裂韧性测试表现低于Cr_(3)C_(2)-NiCr涂层。3种涂层的摩擦系数及波动均大于TC4钛合金基材。Cr_(3)C_(2)-NiCr涂层对TC4的切削和NiCr涂层对TC4的黏着导致了TC4对磨副的严重磨损。中等硬度的Ni50涂层对TC4的切削和黏着作用分别弱于Cr_(3)C_(2)-NiCr和NiCr涂层,TC4对磨副的磨损损失最低。结论采用超音速火焰喷涂技术制备Ni50涂层可以降低TC4钛合金基体和摩擦副的黏着磨损损失,本研究为钛合金表面耐磨涂层的设计和提高钛合金零部件间的摩擦性能提供了一种可行的方案。
The wear resistance of titanium alloy is one of the most important factors which affect its performance and service life.In previous studies,the wear resistance of titanium alloy surface protective coatings was mainly researched with stainless steel and Si_(3)N_(4) ceramics as friction pairs,and there was a lack of research on the wear performance between the protective coating and titanium alloy.In order to reduce the abrasion and find out a wear-resistant coating system that is applicable for the friction between titanium alloy parts,Cr_(3)C_(2)-NiCr,Ni50,and NiCr coatings,with high,medium,and low hardness,respectively,were sprayed on the surface of TC4 titanium alloy by HVOF.A scanning electron microscope(SEM)and a microhardness tester were used to analyze the microstructure and mechanical properties of the coatings.The tribological properties of the coatings in friction with TC4 titanium alloys were measured with a versatile friction and wear test machine.The results of the mechanical and wear test results showed that the hardness of Ni50 and NiCr coatings was lower than that of the Cr_(3)C_(2)-NiCr coating.The lower hardness of Ni50 and NiCr coatings lead to the cracks generated at particle interfaces that around the indention when they were subject to a load of 49 N.However,differ from the crack morphology of Ni50 and NiCr coatings,the cracks in higher hardness Cr_(3)C_(2)-NiCr coatings propagated along the particle interface.The fracture toughness of the two coatings was 3.58 MPa·m^(1/2) and 1.69 MPa·m^(1/2),respectively,which were lower than that of Cr_(3)C_(2)-NiCr coatings with a value of 3.65 MPa·m^(1/2).The hardness of TC4,Cr_(3)C_(2)-NiCr,Ni50 and NiCr coatings were 314HV0.3,1120HV0.3,680HV0.3,and 438HV0.3,respectively.However,the Ni50 coatings,as well as,the TC4 friction pair that was in friction with Ni50 coatings showed the lowest specific wear rate and wear loss,with the value of 0.87×10^(-7) mm^(3)/(N·m)and 2.84 g,respectively.The coating specific wear rate of Ni50 coatings was 2.53,0.84,and 0.08 times than TC4 alloy,Cr_(3)C_(2)-NiCr,and NiCr coatings,respectively.Meanwhile,the wear loss of the TC4 friction pair in friction with Ni50 was 1.1,0.3,and 0.04 times than the friction pair that was in friction with TC4 alloy,Cr_(3)C_(2)-NiCr,and NiCr coatings,respectively.The wear mechanism of the TC4 substrate in friction with TC4 was adhesive wear,which was same with NiCr coatings in friction with TC4 friction pairs.Due to the low fracture toughness,the NiCr coating sufferred a much greater wear loss than Cr_(3)C_(2)-NiCr and Ni50 coatings.The wear mechanism of Cr_(3)C_(2)-NiCr coatings and TC4 friction pairs was adhesive wear and abrasive wear,resulting in a significant cutting effect and leading to a greater wear loss of TC4 friction pairs.The Ni50 coatings showed a moderate hardness but a relatively large fracture toughness compared with Cr_(3)C_(2)-NiCr and NiCr coatings.The cutting effect and adhesion effect of Ni50 coatings on friction pairs was lower than that Cr_(3)C_(2)-NiCr coatings and NiCr coatings,respectively,and the wear loss of the coatings and friction pairs was lower than the other two.In summary,the Ni50 coatings prepared by HVOF can reduce the adhesion wear loss of TC4 titanium alloy substrates and friction pairs.This study provides a feasible scheme for the design of wear resistant coatings on titanium alloy surfaces and for the improvement of friction properties between titanium alloy parts.
作者
刘畅
张春晖
杜鹏程
许建亮
高名传
陈同舟
LIU Chang;ZHANG Chunhui;DU Pengcheng;XU Jianliang;GAO Mingchuan;CHEN Tongzhou(Wuhan Research Institute of Materials Protection,Wuhan 430030,China;State Key Laboratory of Special Surface Protection Materials and Application Technology,Wuhan 430030,China;Wuhan Marine Machinery Plant Co.,Ltd.,Wuhan 430080,China;Lingyun Science&Technology Group Co.,Ltd.,Wuhan 430030,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2024年第5期69-77,共9页
Surface Technology
基金
煤燃烧国家重点实验室开放基金资助项目(FSKLCCA1901)
中国机械科学研究总院集团有限公司技术发展基金项目(FZJJ202129)。
