Crystal Plasticity and Grain-Orientation-Dependent hkl-Lattice Strain in Polycrystalline SUS316

Abstract

Non-uniform deformation at the micro-structural level is considered as critically important because it contributes a lot to study the early stage failure process in engineering components. To understand the deformation micro-mechanisms of stainless steels under complex stress states, we start with the heterogeneous deformation examination at the grain level under uniaxial loading condition and try to correlate the micro-deformation with the intergranular damage existing in many industrial processes. Due to the popularity, stainless steel 316 polycrystal is chosen in this study. The crystal plasticity finite element method (CPFEM) based on the crystalline slip theory is employed to establish a fundamental framework to predict the lattice strain evolution. Single-crystal elastic constants as part of the input information for CPFEM are obtained through the least square fitting to the neutron diffraction lattice strain data. Yielding behavior and the load carrying responsibility onset of the plastic deformation are discussed among several crystallographic planes, leading to the insight discussion between the lattice strain evolution and intergranular damage.