Microstructure and Anisotropy of the Mechanical Properties of 316L Stainless Steel Fabricated by Selective Laser Melting

Significant anisotropy in mechanical properties was observed in 316L stainless steel (SS) that was subjected to selective laser melting (SLM) to produce a hierarchical structure, composed of molten pool, columnar grains, and a cellular substructure. Such anisotropy was induced by the geometric relationship between the boundary of the molten pool and the tensile force. The in situ tensile test showed initial deformation rapidly occurred at the boundary of the molten pool, followed by strain localization, and a lower ductility was obtained when loaded in the longitudinal direction (perpendicular to the molten pool). By contrast, the deformation was significantly constrained because of the geometry of the boundary of the molten pool, and substantial deformation occurred in the cellular substructure during loading in transverse direction (parallel to the molten pool). Finally, the quantitative analysis revealed that the high-level strength was attributed to the high-density dislocations and the fine cellular substructure.

Automated summary

Significant anisotropy in mechanical properties was observed in 316L stainless steel produced through selective laser melting, with initial deformation occurring rapidly at the boundary of the molten pool. The high-level strength was attributed to high-density dislocations and the fine cellular substructure, with lower ductility obtained when loaded in the longitudinal direction and substantial deformation occurring in the cellular substructure during loading in the transverse direction.