Effect of overlap pattern on the residual stress, surface morphology and fatigue properties of Ti-6Al-4V alloy by multiple laser shock peening

Abstract

In this study, the effects of the laser shock peening (LSP) pattern on the fatigue properties of Ti-6Al-4V alloy were investigated. The residual stress distribution and surface morphology generated by LSP were analyzed using both experiments and numerical simulations. The results show that by optimizing the LSP patterns and overlap ratios, deep compressive residual stresses and beneficial surface morphology can be obtained, resulting in a significant improvement of the four-point bending fatigue performance. Specifically, LSP without optimization improves the fatigue life by a factor of 1.68 when the stress level is 550 MPa and the stress ratio is 0.1, while LSP with optimized parameters improves the fatigue life by a factor of 29.67. It has been demonstrated that the optimization of LSP patterns and overlap ratios plays an important role in enhancing the surface integrity and, thus, the fatigue performance of the Ti-6Al-4V alloy.