Electron Backscatter Diffraction-Enabled Anisotropic Thermo-Elastic Analysis of Additively Manufactured Single Tracks

Abstract

Despite extensive efforts directed toward elucidating the connections between process, microstructure and performance of additively manufactured structures and components, a significant number of meaningful questions remain unanswered. Specifically, a large body of work has demonstrated that microstructural/sub-structural features in selectively laser melted (SLM) components give rise to a significant enhancement in strength. Furthermore, the change in associated ductility is comparable to that seen in post-processed, wrought annealed material. However, the origin and mechanism by which these features arise have remained elusive. This work is an initial step in leveraging computational capabilities for validating experiment-based theories that explain the basis for the above-mentioned phenomena. The present work describes a computational approach for utilizing spatially resolved crystal-lographic descriptions obtained via electron backscatter diffraction (EBSD) to define the domain geometry and material properties of an anisotropic thermo-elastic simulation. The resulting solution is used to ascertain the elastic strain energy state, and slip-system resolved shear stresses on a per-grain basis. This analysis is performed, in part, as a means for validating a hypothesis linking these characteristics with the development of sub-structural features, which are in turn, correlated with improvements in material performance. The results suggest that both strain energy density and grain boundary character play an important role in the formation of substructure in additively manufactured 316L stainless steels.