Influence of post-processing techniques on the microstructure, properties and surface integrity of Al Si Mg alloy processed by laser powder bed fusion technique

Abstract

The present work investigates the influence of post-processing techniques such as heat treatments (T5 and T6 conditions) and the shot peening (SP) under peening pressures such as 3 bar (SP-3) and 6 bar (SP-6) on the LPBF processed AlSi10Mg alloy. The microstructures of as-printed and heat-treated samples revealed a density of greater than 99.9%. The micro-hardness, yield and tensile strength properties were similar in both as-printed and heat-treated (T5) conditions. However, the samples of the heat-treated (T6) showed lower micro-hardness, yield and tensile strength properties than as-printed and heat-treated (T5) samples. There was a significant decrease in surface roughness and a notable improvement in surface hardness for shot-peened samples compared to the as-printed samples. SP process decreased the surface roughness parameter values by more than about ~50% compared to the as-printed samples. The SP-3 condition induced a smoother surface (~12%) than the SP-6 condition on the LPBF processed AlSi10Mg samples. Overall, the employed post-processing techniques such as heat treatment and shot peening on the LPBF processed AlSi10Mg alloy exhibit improved isotropic mechanical properties and surface integrity. • Post-processing techniques such as heat treatments and the shot peening on the LPBF processed AlSi10Mg alloy is studied. • The micro-hardness and tensile properties of T5 were higher than T6 conditions. • SP process decreased the surface roughness by more than about ~50% compared to the as-printed samples. • The SP-3 condition induced a smoother surface (~12%) than the SP-6 condition.