The Effect of the Iso‐Thermal Heat Treatment on the Microstructure and Properties of Powder Bed Fusion–Laser Beam AlSi10Mg Alloy

Abstract

The effect of iso‐thermal heat treatments on powder bed fusion–laser beam (PBF–LB) AlSi10Mg alloy has been studied; however, an extensive process–property relationship evaluation has not yet been undertaken. In addition, the coarsening of eutectic Si from low‐to‐high (200–500 °C) temperature heat treatment has not been investigated systematically. Therefore, AlSi10Mg alloy is heat‐treated at 200, 300, 400, and 500 °C for holding times ranging from 0.5 to 32 h. Uniaxial tensile and hardness tests are conducted, and the microstructure is characterized. A unique approach is adopted for estimating Si solubility where 200 °C heat‐treated microstructure data to estimate solute trapping due to the high cooling rate in the as‐fabricated state. It is observed that increasing the heat‐treatment temperature and time reduces the strength and strain‐hardening rate but increases the tensile elongation up to 400 °C heat treatment. At 500 °C, the yield strength increases, and the elongation reduces compared with the 400 °C heat treatment owing to the refined Fe containing dispersoid formation at 500 °C. The important outcome of this study is heat‐treatment process–property contour maps that are useful for fine‐tuning the mechanical properties of PBF–LB AlSi10Mg alloy for industrial prototyping application.