3D simulations of microstructure and comparison with experimental microstructure coming from OIM analysis

This paper presents a new methodology to create realistic 3D microstructures of polycrystals. The virtual microstructures are based on statistical data describing the morphological and crystallographic textures of a sample, obtained from an EBSD analysis. In addition, the methodology can reproduce the observed surface on top of the simulated microstructure. This feature allows finite element calculations on these virtual aggregates to be compared to experimental results of mechanical tests. Such a comparison leads to the identification of the mechanical parameters of constitutive laws, such as critical resolved shear stress and strain hardening, using an optimization algorithm. Two materials were simulated in this study: TiAl and grade 702 zirconium. The first one presents twins inside the microstructure and the second one has an anisotropic texture. Based on 2D simulations, the important parameters necessary to describe a microstructure were identified as grain size, grain shape and crystallographic orientation distributions. Then, a methodology was developed to extend this surface observation to a realistic volumetric description necessary to simulate 3D microstructures. Finally, multiple slices of a virtual 3D microstructure were compared to an experimental surface observation in order to validate the proposed methodology. (authors)