关键词: Nd∶YLF平顶激光冲击, TC6钛合金, 表面残余应力, 表面微变形, 粗糙度

Abstract: To study the effect of laser shock peening on surface stress and deformation of the TC6 titanium alloy under the condition of high frequency, a Nd∶YLF flat-top laser was used to perform laser shock peening test on TC6 titanium alloy specimens at a repetition frequency of 10 Hz, and the influence of laser energy and impact times on surface residual stress and deformation of the specimen was analyzed. The residual stress on the surface of the TC6 titanium alloy specimen was measured by using XL-640 X-ray stress tester before and after impact, and the three-dimensional morphology and surface roughness of the specimen were measured by using Contour GT-X3 white light interferometer. The results show that, for Nd∶YLF flat-top laser shock peening, the spot overlapping rate of 30% is more appropriate choice than that of 50%, because the overlapping rate of 50% is liable to cause surface ablation of specimen. With the increase of laser energy and impact times, the residual stress, surface deformation and surface roughness of the specimen surface all increase. For the single spot non-overlap area, the variation gradient of specimen surface deformation is relatively gentle, while in the spot overlap area, the surface deformation of specimen approximately presents a “V”-shaped change.

Key words: Nd∶YLF flat-top laser shock, TC6 titanium alloy, surface residual stress, surface micro-deformation, roughness