The deformation and fracture behavior of 316L SS fabricated by SLM under mini V-bending test

Abstract

In the present study, mini V-bending testing was conducted on 316L stainless steel specimens fabricated by selective laser melting (SLM). In order to analyze the microstructure evolution during the V-bending test, FE-SEM and EBSD techniques were performed along the building (BD) and scanning directions (SD). Microstructure analysis revealed that the as-fabricated SLM specimens contained pores in the surface and subsurface regions, which affected the deformation and fracture behavior during the V-bending process. The effect that these microstructural heterogeneities exerted on the deformation behavior of the SLM specimens is discussed herein with respect to the evolution of the Kernel average misorientation (KAM), grain boundaries (GBs), and Σ3 twin boundaries (TBs). Two-level finite element (FE) simulations were performed to explain the deformation and fracture behaviors during the V-bending process. The first-level FE simulation was done to understand the macroscopic deformation of the specimen during the V-bending process. During the second-level FE simulation, representative volume elements (RVEs) were considered in discussing the evolution of equivalent plastic strain and stress triaxiality at regions near the pores. High equivalent plastic strain and stress triaxiality states at regions near the pores in the surface and subsurface of the specimens made a considerable contribution to the nucleation and propagation of cracks during the V-bending process.