Mechanical Properties of AlSi10Mg Processed by Laser Powder Bed Fusion at Elevated Temperature

Abstract

AlSi10Mg processed by laser powder bed fusion is expected to have remarkable mechanical properties due to the dominant cellular microstructure. However, the as-processed material is often both anisotropic and containing significant residual stresses. To mitigate these problems, a retrofitted heating system was used to elevate the process temperature to 200°C. The characterization results show low levels of porosity, anisotropy and residual stress. Furthermore, the effect of three heat treatment conditions (as-built, stress relief, and T6) on the tensile properties was investigated. For this purpose, 14 tensile samples were built in seven different orientations. Digital image correlation was used to understand the deformation mechanism for each heat treatment condition. It was observed that the as-built material has comparable properties to the stress relieved condition, while T6 heat treatment resulted in increased ductility. Based on the results, LPBF processing of AlSi10Mg at elevated temperature can potentially eliminate the need for post-process stress relief heat treatment.