On the effects of laser shock peening on fatigue behavior of V-notched AlSi10Mg manufactured by laser powder bed fusion

Abstract

Post-processing methods can efficiently reduce the negative effects of the internal and surface defects in as-built laser powder bed fusion materials. In this study, the influence of different post-treatments including T6 thermal treatment and laser shock peening were investigated individually and synergistically together with electro-chemical polishing on microstructure, surface morphology, roughness, hardness and residual stresses as well as rotating bending fatigue behavior of V-notched LPBF AlSi10Mg samples. The results indicated that laser shock peening has a high potential to close the sub-surface pores up to a depth of 390 and 420 µm leading to an overall mean porosity reduction of 52% and 62% in the as-built and heat treated samples, respectively. In addition, the hybrid post-treatment of heat treatment + laser shock peening + electro-chemical polishing was found to remarkably improve the fatigue life up to 400 times longer compared to the as-built state.