静态接触中表面纹理对塑性变形界面微凸体平坦化的影响

Effect of Surface Texture on Asperity Flattening at Plastic Deformed Interface in Static Contact State

试验研究了静态接触中表面纹理对塑性变形界面微凸体平坦化的影响。运用抛光技术制备了两种试件表面:单向纹理表面和各向同性表面。采用HDM-20端面摩擦试验机,分别在有、无润滑油条件下对试件进行了压缩试验。用JM-6200型光学显微镜观测试件表面形貌结构的变化;用Talysurf CCI Lite测量三维表面参数,并选取S_a、S_(al)、S_(tr)、S_(dr)和S_(dq)等参数来定量描述试件表面形貌结构的变化。结果表明,试件表面纹理对微凸体平坦化行为具有明显的影响,无润滑油时各向同性表面微凸体平坦化程度大于单向纹理表面,但有润滑油时刚好相反;表面纹理对微凸体平坦化的影响使得三维表面参数发生了规律性变化。基于机械流变模型的分析表明,封闭润滑油坑的出现导致了有润滑油时表面纹理影响微凸体平坦化行为。通过封闭润滑油坑特征的提取,验证了分析的正确性。

The effect of surface texture on asperity flattening at plastic deformed interface in static contact state has been investigated experimentally. Two types of surfaces textures of specimens, isotropic surface and solely directional surface, are obtained by polishing. A series of compression tests are carried out with lubricant and without lubricant respectively using HDM-20 End-Face Tribometer. The three dimensional surface topography of the specimens are observed by means of JM-6200 optical microscope. The three dimensional surface parameters are measured with Talysurf CCI Lite. The variations of surface microstructure are analyzed by choosing such parameters as Sa, Sal, Str, Sdr and Sdq. The experimental results show that the surface texture of specimens has a significant effect on asperity flattening. The isotropic surface exhibits a higher rate of asperity flattening than the solely directional surface without lubricant, while an opposite situation occurs with lubricant. The effect of surface texture on asperity flattening leads to regular changes of the three dimensional surface parameters. Based on mechanical-rheological model, it comes to a conclusion that the effect of surface texture on asperity flattening with lubricant can be attributed to the presence of closed lubricant pockets, which is validated by the extraction of the closed lubricant pocket features.