Microstructure and Mechanical Properties of AlSi10Mg Parts Produced by the Laser Beam Additive Manufacturing (AM) Technology

Selective laser melting (SLM) is an additive manufacturing (AM) technique for fabrication of near net-shaped parts directly from computer-aided design data from a series of layers each one melted on top of the previous one by a laser beam. AlSi10Mg specimens were produced by the SLM technique from gas atomized pre-alloyed powders. The study shows the distinctive layered macrostructure, and the extremely fine cellular dendritic microstructure obtained by the SLM AM process, along with the remarkable tensile testing results for AlSi10Mg components. High thermal gradients determine the small grain sizes of the microstructure. Electron microscopy revealed anisotropy of the parts, inherent to the AM-SLM process, dependent on the build orientation. A ductile, dimpled failure mode was observed in these specimens as expected for a relatively ductile microstructure. It is shown that AlSi10Mg parts produced by SLM display room temperature mechanical properties comparable or even exceeding to those of conventionally cast AlSi10Mg.