Application of gradient severe shot peening as a novel mechanical surface treatment on fatigue behavior of additively manufactured AlSi10Mg

Post-processing methods can be crucial in addressing the associated anomalies of the as-built state of additively manufactured materials. In this study, for the first time, the effects of gradient severe shot peening as a novel mechanical surface treatment, along with other types of shot peening treatments, including conventional, severe, and over shot peening processes were investigated individually and combined with heat treatment on fatigue behavior of hourglass AlSi10Mg samples fabricated by laser powder bed fusion. Detailed experimental characterizations in terms of microstructure, porosity, surface texture, hardness and residual stresses as well as rotating bending fatigue behavior were conducted. The experimental results revealed a significant fatigue behavior improvement after applying gradient severe shot peening treatments due to their remarkable capacity to modulate surface texture, known as a side effect of peening, besides surface layer nanocrystallization, enhanced hardness, and high compressive residual stresses.