金属材料表面形貌对微观力学行为的影响

利用原子力显微镜对不同金属试件表面的三维形貌进行了定量表征和分析,并通过建立有限元模型研究了表面微观应力集中的分布及变化.结果表明:不同的表面处理方式、不同的材料性质对表面微观形貌的影响非常明显,而且在金属表面,微观应力的分布与其微观形貌紧密相关,当表面处理方式改变时,表征参数的全面改变是导致微应力集中变化的主要原因,在评价表面状态对疲劳性能的影响时,不能仅考虑表面粗糙度的改变,应当综合分析各表征参数的变化.

Effect of Surface Topography on Micro-Mechanical Behavior for Different Metallic Materials

Surface topographies of different machined specimens from three typical metallic materials,stainless steel,Ti alloy and Al alloy,have been quantitatively characterized and analyzed to investigate the effect of surface topography on micro-stress concentrations based on the atomic force microscope measurement and finite element simulation.It is found that the surface topography is significantly influenced by the surface treatment method.However,the surface characteristic parameters have shown different variation rules for different metals.It is not only the surface roughness parameters but all characteristic parameters that determine the micro-stress concentrations caused by the surface conditions.Therefore,the integrated influences of surface characteristic parameters on micro-stress behaviors should be considered to estimate the effect of surface conditions on material fatigue performance effectively.