Influence of laser process on the porosity-related defects, microstructure and mechanical properties for selective laser melted AlSi10Mg alloy.

Correlations among the laser process, microstructure, porosity-related defects, and mechanical properties for selective laser melted AlSi10Mg alloy were investigated through experiments. A series of samples were produced with various laser parameters, and the porosity-related defects and microstructure were characterized by using X-ray computed tomography and scanning electron microscope. A model is proposed based on the energy density to reflect the evolution of the sample density with changing laser parameters; the optimal energy density level is evident when the sample density reaches 99.5%. Furthermore, the model has good applicability for both the volumetric energy density and deposited energy density parameters. In addition, defect evolution with increasing energy density, namely, the transition from lack of fusion defect domination to pore defect domination, is identified by considering anisotropy and sphericity factors simultaneously. The results also indicate that the porosity and Al-Si eutectic microcell have different effects on the mechanical properties. The negative correlation between the cell size and microhardness is built. The tensile strength highly depends on the porosity while the yield strength is mainly associated with the Al-Si eutectic structure. [ABSTRACT FROM AUTHOR]