Fatigue behavior of selective laser melted 316L stainless steel: Experiments and modeling

Abstract

Selective laser melting (SLM) is extensively applied in fabricating 316L stainless steel structures. In this study, a series of mechanical tests were conducted on SLM 316L stainless steel, including tensile testing, high cycle fatigue (HCF) testing at various stress ratios and mean stresses, and low cycle fatigue (LCF) testing at different strain amplitudes. A efficient method of processing CT images was employed to analyze the porosity and fatigue failure behavior of material. Additionally, we proposed an elasto-plastic fatigue damage evolution model takes porosity into account, with relevant parameters determined through experiments. The predicted life under experimental conditions was calculated using the UMAT and DISP subroutines in ABAQUS software. Results indicate that mean stress significantly reduces fatigue strength, and irregularly shaped pores are the primary cause of material failure and reduction in strength. The predicted life of the elasto-plastic fatigue damage model is in good agreement with the experimental results. These results have important implications for the design and maintenance of SLM 316L stainless steel structures.