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 various iso‐thermal heat treatments on powder bed fusion‐laser beam (PBF‐LB) AlSi10Mg alloy has been widely studied; however, a process‐property relationship has not yet been established. In addition, the eutectic Al‐Si network breakdown and coarsening of eutectic Si from low‐to high (200oC–500oC) temperature heat treatment has not been investigated systematically. Therefore, the AlSi10Mg alloy is heat‐treated at 200oC, 300oC, 400oC, and 500oC for various holding times ranging from 0.5 to 32 hours. Uniaxial tensile and hardness tests are conducted, and the microstructure is characterised in detail. A unique approach is adopted for estimating Si solubility where 200oC heat‐treated microstructure data is used to estimate solute trapping due to the high cooling rate in the as‐fabricated state. Furthermore, it was observed that increasing the heat treatment temperature and time reduces the strength and strain hardening rate but increases the tensile elongation up to 400oC heat treatment. Above 500oC, the yield strength increases, and the elongation reduces compared with the 400oC heat treatment owing to the refined Fe containing dispersoid formation at 500oC. 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 rapid prototyping application.This article is protected by copyright. All rights reserved.