Synergistic Effects of Solution Treatment, Aging, and Shot Peening on the Microstructure, Mechanical Properties, and Surface Integrity of SLM-Fabricated AlSi10Mg Alloy

Abstract This study investigates the effects of shot peening (SP) performed after solution treatment (ST) and aging on the microstructure, mechanical properties, and surface quality of AlSi10Mg alloy produced by selective laser melting (SLM). ST was conducted at 540°C for 2 hours, followed by aging at 180°C for 6 hours, whereas SP was performed using various processing parameters. Microstructural examinations, tensile tests, and analyses of microhardness, density, and 3D surface topography were performed. The results indicated that ST and aging reduced tensile strength while increasing elongation at break. SP increased the yield strength of the heat-treated samples; for the sample subjected to SP after aging, this value exceeded that of the as-built condition (reaching 267 MPa). Furthermore, SP reduced surface roughness across all processing conditions. The lowest Ra and Rq values, 0.30 µm and 0.40 µm, respectively, were observed in the sample subjected to SP after ST. Conversely, the near-surface microcracks and reduced ductility observed after SP highlighted the need for a comprehensive evaluation of mechanical properties. The findings demonstrate that SP is a complementary process that enhances the mechanical properties and surface quality of the heat-treated AlSi10Mg; however, processing parameters must be optimized with due consideration for surface integrity and ductility.