Effect of laser scanning angle on shear slip behavior along melt track of selective laser melted 316L stainless steel during tensile failure

The improved mechanical properties have been recently realized in 316 L stainless steel (SS) materials processed by additive manufacturing (AM) techniques, owing to its cross-scale structure, especially the formation of cell-structure. However, their heterogeneous structure also inevitably leads to significant mechanical anisotropy which may impede their further applications. For revealing the impact of microstructural heterogeneity on anisotropic properties of AM processed parts, this work prepared 316 L SS components using selective laser melting (SLM) techniques under different laser scanning angles. Their tensile performances are examined, and the relationship between the origin points of deformation failure and molten pool boundary is established. The results show that when the laser scanning angle is parallel with the tensile loading direction, the elongation of 316 L stainless steel fabricated by SLM is the highest, reaching 52.5%. Meanwhile, the maximum yield strength of 687.5 MPa was obtained when the laser scanning angle was 30–45°. The main reason is that the mechanical properties of the SLM parts change with the adjustment of scanning angle due to the effect of short edge grain size and poor orientation of the low grain. So, this study will provide new insights into the microscopic fracture mechanism in SLM parts.