Influence of boundary conditions on bi-phased polycrystal microstructure calculation

Abstract

In this paper, polycrystalline bi-phased microstructure calculations were performed using finite element (FE) method and compared to mechanical fields measured experimentally using a digital image correlation (DIC) technique. From scanning electron microscopic (SEM) observations and electron back-scattered diffraction (EBSD) crystal orientation measurements performed on an austenitic-ferritic stainless steel test specimen, a quasi-2D numerical polycrystalline microstructure was constructed. Mechanical behaviors of austenitic (FCC) and ferritic (BCC) grains were modeled by two crystal plasticity laws, based on crystallographic slips and dislocation densities. FE mechanical fields were calculated using two types of boundary conditions: the displacements measured by DIC, and the average of the displacements measured by DIC. A better description of intraphase and intragranular strain heterogeneities is obtained using as boundary conditions the displacements measured instead of the average of the displacements measured.