comparative study on microstructure, tensile properties and fatigue strength of slm and wrought 316l stainless steel

Selective laser melting (slm) is the most popular technology for additive manufacturing (am) of metallic parts. the slm 316l stainless steel has been studied due to wide range of applications stemming from its excellent mechanical and corrosion properties. the microstructure, tensile properties and fatigue strength of the as-built 316l specimens fabricated by slm are comprehensively investigated and the results are compared to those of the wrought material. it is observed that the slm 316l microstructures were composed of a bimodal grain size distribution. they show a significant yield strength increase as well as a considerable ultimate strength increase which can be explained by the multi-scale microstructural features. the fatigue strength of as-built materials is significantly reduced by the surface roughness and process-induced defects which are highly concentrated near to the surface. thus, possibilities for fatigue strength improvement include surface post-treatment.