载荷及位移幅值对DLC薄膜微动磨损行为

Effects of Load and Displacement Amplitude on Fretting Wear Behavior of DLC Film

为了提高TC4钛合金表面的抗微动磨损性能,在本文中采用非平衡磁控溅技术(Unbalanced Magnetron Sputtering)在TC4钛合金表面沉积了类金刚石(DLC)薄膜.采用球/平面接触形式研究了DLC薄膜的微动摩擦磨损行为.在不同法向载荷和位移幅值下,结合微动运行工况图研究了DLC薄膜滑移状态和损伤机理.利用原子力显微镜、纳米压痕仪、激光拉曼光谱仪、激光共聚焦显微镜、场发射扫描电子显微镜和SRV-V微动摩擦磨损试验机等设备对DLC薄膜进行性能的表征和微动摩擦磨损性能测试.通过微动图,摩擦耗散能,磨痕形貌、化学成分分析揭示其损伤机理.结果表明:载荷和位移幅值对DLC薄膜微动摩擦磨损行为和损伤机理有显著影响.当位移幅值为25μm时,微动运行于混合滑移(mixed slip regime,MSR)情形下,当位移幅值为100μm时,微动运行于完全滑移(gross slip regime,GSR)情形下.小位移幅值时,DLC薄膜磨损机理是磨粒磨损为主;大位移幅值时,DLC薄膜磨损机理是黏着磨损为主.干摩擦条件下,DLC薄膜有良好的抗微动磨损性能,关键就在于其优异力学性能和自润滑特性.

In order to improve the fretting wear resistance of TC4 titanium alloy,diamond-like carbon(DLC)films were deposited on the surface of TC4 titanium alloy by unbalanced magnetron sputtering(UBMS)technique.The fretting friction and wear behaviors of DLC film against GCr15 steel ball were studied using a ball-on-flat contact.Under different normal loads and displacement amplitudes,the slip regime and wear mechanism of DLC film were studied with the running condition fretting map(RCFM).The characterization and fretting friction and wear performance of DLC films were carried out by means of atomic force microscopy,nanoindentation,laser Raman spectroscopy,threedimensional optical profilometer,laser confocal microscope,field emission scanning electron microscope and SRV-V fretting friction and wear tester.The damage mechanism was revealed through the analysis of fretting maps,dissipated energy,the morphology and chemical composition of wear track.The results showed that the displacement amplitude and normal load had great effect on the fretting mode and damage mechanism.The mixed slip regime(MSR)was dominant at the displacement amplitude of 25μm.On the other hand,the slip regime was gross slip regime(GSR)at the displacement amplitude of 100μm.The abrasive wear was the main damage mechanism of DLC film under small displacement amplitude,whereas under larger displacement amplitude the wear mechanism of DLC film was mainly adhesive wear.In short,the good fretting wear performance of DLC film in dry friction lies in its excellent mechanical properties and self-lubricating properties.