Effect of substrate material on the molten pool characteristics in selective laser melting of thin wall parts

Substrate plays an important role in selective laser melting (SLM). In general, the same material substrate is utilized as the powder for SLM. However, there are considerable kinds of aluminum alloy and their physical properties are different. In this work, the effect of three aluminum substrates AlSi10Mg, 6061, and 7050 on the molten pool characteristics was investigated for SLMed AlSi10Mg thin wall parts by experimental and numerical analysis. The thermal behaviors, molten pool characteristics, microstructure, silicon distribution, and microhardness were studied as the deposited layers increase. Results show that these features of the three substrates are different at the first several layers of the thin wall parts then become the same after definite layers. Our results clarify the influence of the substrate materials on the SLM of aluminum thin wall parts, which has important theoretical significance and engineering application.