Weakest region analysis of non-combustible Mg products fabricated by selective laser melting

Abstract

In this study, several Mg-9%Al-2%Ca alloy specimens were made using selective laser melting process (SLM) and subsequently subjected to tensile testing. Results showed that the microstructure of this specimen consist of fine grain, which serves to harden the material, and coarse grain, which is defined by the relatively slowly cooled region, softening the material and increasing its plasticity. The coarse grain tended to preferentially solidify immediately below the outer surface of the sample, which could lead to a stable crack propagation that originated from a defect located at the surface as a consequence of the intrinsic irregularity of SLM processes, the effects of which must be considered in order to determine the fracture toughness. Based on this information, corresponding measures can be provided in order to improve the process stability for non-combustible magnesium products.