Crystal plasticity modeling of mechanical anisotropy in additive manufacturing 316L stainless steel: Influence of build orientation and scan rotation angle

Abstract

316L-stainless steel (316L-SS) fabricated via laser powder bed fusion (LPBF) exhibits significant mechanical anisotropy in terms of strength and ductility. This study demonstrates that anisotropy is primarily influenced by build orientations (BOs) and scan rotation angles (SRAs). The key governing mechanisms were investigated experimentally, revealing that variations in dislocation density play a dominant role, while crystallographic texture differences further contribute to the anisotropic response. To better understand this behavior, a novel crystal plasticity finite element modeling (CPFEM) was developed to simulate mechanical anisotropy. The two most representative BOs (0° as X0 and 45° as XY45) and SRAs (0° as R0 and 67° as R67) were selected, with all samples printed on the horizontal plane. Using experimentally calculated dislocation density and microstructural data for each case, synthetic representative volume elements (RVEs) were generated and employed in mechanical simulations using the open-source DAMASK software. The simulated stress–strain curves closely matched the experimental results across all conditions, with a maximum error of 10% observed for the XY45–R67 sample. This demonstrates that the developed model effectively captures the influence of dislocation density variations and microstructural characteristics on mechanical anisotropy induced by different BOs and SRAs.