Microstructural modeling and measurements of anisotropic plasticity in large scale additively manufactured 316L stainless steel

In this paper, the wire + arc additive manufacturing process-induced plastic anisotropy of 316L stainless steel is analyzed by means of detailed 3D microstructural modeling and compared to experimental tensile tests. A spatially varying representative grain texture and morphology are incorporated in a representative volume element having the size of a single fusion zone and which is generated using a 3D anisotropic Voronoi algorithm. The constitutive behavior is modeled at the grain scale by a finite element crystal plasticity framework, of which the corresponding parameters are obtained from experimental tensile tests in one of the processing directions. As a result of the spatially correlated grain orientations inside the fusion zone, distinct deformation patterns and strain localizations have been observed during experimental tensile tests. The strain fields obtained from numerical simulations are compared to the experimental deformation patterns and a remarkable correspondence is observed. Numerical simulations are also performed in various uniaxial loading directions to predict the 3D yield behavior. A strongly anisotropic plastic response is obtained and a convincing match between the numerical model and experimental tensile tests is found in various loading directions.