材料表面形貌对激光冲击强化残余应力的影响

建立材料表面为凹面、凸面和平面的三种有限元模型,研究材料表面形貌对激光冲击强化Ti6Al4V钛合金残余应力的影响。当材料表面曲率半径大于光斑半径时,相对于材料表面为平面的工况,凹面表层产生的残余压应力偏大,并随着凹面曲率半径的减小而增大；凸面表层产生的残余压应力偏小,并随着凸面曲率半径的减小而减小。当材料表面曲率半径小于光斑半径时,凹面或凸面模型的激光冲击强化的残余压应力均不及于材料表面为平面的工况。

Influence of the surface topography on the residual stresses induced by laser shock processing

Three kinds of finite element models associated with the concave surface,convex surface and plane surface to be treated are developed to study the influence of the surface topography on the residual stresses induced by laser shock processing of Ti6Al4V alloy.In the case that the surface curvature radius is larger than that of laser beam,when compared with the compressive residual stresses result from the model with plane surface,the larger compressive residual stresses in the surface and subsurface are produced by the model with concave surface,and the stresses increase with the decrease of the curvature radius;conversely,the smaller compressive residual stresses in the surface and subsurface are produced by the model with convex surface,and the stresses decrease with the decrease of the curvature radius.In the case that the surface curvature radius is smaller than that of laser beam,the compressive residual stresses in the surface and subsurface in the cases of concave and convex surface are less than that in the case of plane surface.