Aging temperature effects on microstructure and mechanical properties for additively manufactured AlSi10Mg

AlSi10Mg alloy was prepared by laser powder bed fusion (LPBF). The evolution of microstructure and mechanical properties after diverse aging temperatures were systematically studied. The metastable ultra-fine cellular structure was obtained for as-built specimens. Aging at lower temperatures (100–225°C) promotes the formation of a large number of Si-rich precipitates, and the original Si networks can be retained. With the increase in aging temperature, Si network gradually broke apart, and Si-rich particles grew and spheroidised. The hardness increases with temperatures up to 175°C, and decreases thereafter, while the opposite trend was observed for elongation. Excellent comprehensive mechanical properties with a tensile strength of 381 MPa and elongation of 5.2% can be obtained at 225°C for 2 h. Highlights The effect of aging temperatures on microstructure stability and mechanical properties of additive manufacturing AlSi10Mg alloy has been revealed systematically. The Si-rich precipitates and eutectic Si network were responsible for the observed mechanical properties changes. A good combination of strength and ductility is obtained at 225°C for 2 h aging heat treatment.