Fatigue Behavior of Selective Laser Melted 316l Stainless Steel: Experimental Characterization and Modeling Prediction

Abstract

Selective laser melting (SLM) has been widely used to fabricate 316L stainless steel structures. In this study, we conducted a series of mechanical tests on SLM 316L stainless steel, including tensile tests, high cycle fatigue tests at different stress ratios and mean stresses, and low cycle fatigue tests at different stress amplitudes. We use a simple and efficient CT images processing method and SEM images to analyze the fatigue failure behavior of materials. We also propose an elasto-plastic fatigue damage evolution model that considers the influence of porosity, with relevant parameters determined through experiments. Using the UMAT and DISP subroutine in software ABAQUS, we calculated the predicted life under experimental conditions. Our results show that mean stress significantly reduces the high cycle fatigue limit of the material, and pores within the material are the main cause of the initiation of high cycle fatigue damage and the fracture of the low cycle fatigue damage. The predicted life of the elasto-plastic fatigue damage model is in good agreement with the experimental results. These findings have important implications for the design and maintenance of SLM 316L stainless steel structures.

Keywords: Additive manufacturing, Fatigue damage model, Fatigue life, 316L stainless steel, fracture behavior