Comparison Between Microstructures, Deformation Mechanisms And Micromechanical Properties Of 316L Stainless Steel Consolidated By Laser Melting

Selective laser melting (SLM) was used to fabricate 316L stainless steel specimens for characterization of microstructures and micromechanical properties under uniaxial loading in-situ in SEM. Correlations between the microstructure, deformation mechanisms and mechanical properties were investigated. The results show that the morphology of microstructure is very different between the horizontal and vertical building direction. In horizontal direction smaller grain size and more deformed microstructure was observed. Under uniaxial loading the yield strength and initial work hardening rate was highest at the horizontally built specimen. The uniform and total elongation was better for the vertical built specimen.  Slip and twinning were the dominant deformation mechanisms with correlation to the observed texture.  The observed anisotropic mechanical behavior can be explained by the differences on the distribution of deformed and sub-structured microstructure along the stain path.