Heterogeneous microstructure and voids dependence of tensile deformation in a selective laser melted AlSi10Mg alloy

Abstract Microstructure and voids evolution of a selective laser melted (SLM) AlSi10Mg alloy during tension were systematically investigated. The SLM AlSi10Mg sample is featured with a multi-level heterogeneous microstructure that is composed of melt pools (MPs), columnar Al grains and sub-cells. According to the Si morphologies and thermal history, the MP could be divided into three regions, including the fine structure zone (FSZ), remelted zone (RMZ) and heat-affected zone (HAZ), respectively. The Si segregation phenomenon on sub-cells boundaries is observed and may attributed to the constitutional supercooling. The tensile deformation behaviors of the vertical sample (V-sample) vary from the horizontal sample (H-sample) for that heterogeneous microstructure arises strain localization in V-sample. In addition, the voids have no obvious effect on the uniform plastic deformation, while they may affect the non-uniform deformation during tension. The combined effects of strain localization and void contribute to the earlier break in V-samples than in H-samples.