Role of Direct Aging and Solution Treatment on Hardness, Microstructure and Residual Stress of the A357 (AlSi7Mg0.6) Alloy Produced by Powder Bed Fusion

Abstract Applying additive manufacturing (AM) technologies to the fabrication of aluminum automotive components, with an optimized design, may result in improved vehicle light weighting. However, post-process heat treatment such alloys has be customized for particular AM microstructure. The present study is aimed at investigating effect different treatments on microstructure, hardness and residual stress A357 (AlSi7Mg0.6) heat-treatable alloy produced by laser-based powder bed fusion (LPBF, also known as selective laser melting). There are two major issues addressed: (1) relieving internal resulting from process (2) strengthening a treatment. Therefore, stress-relief annealing treatment, direct aging as-built redesigned T6 (consisting shortened high-temperature solution followed artificial aging) were examined. Comparable values reached LPBF treatments, but complete relief was obtained only T6. Microstructural analyses suggested that, because supersaturated solid solution, phenomena involved