On the effects of laser shock peening on fatigue behavior of V-notched AlSi10Mg manufactured by laser powder bed fusion. (October 2022) - Maleki, Erfan
Highlights: Effects of HT, LSP, ECP and their combination were investigated on fatigue behavior of notched LPBF AlSi10Mg samples. LSP has a high potential to close sub-surface pores up to a depth of 420 µm in heat treated sets. ECP was found to be more efficient for roughness reduction. Hybrid treatment of HT + LSP + ECP improved the fatigue life up to 400 times higher compared to the AB state. Lower residual stress relaxation rate was observed in heat treated samples during fatigue tests. 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.