Representative volume element model for quantitatively predicting the influence of 3D polycrystalline morphology on Coble creep deformation

Abstract

To evaluate creep in materials under actual-use conditions, it is necessary to consider the polycrystalline morphology. Herein, we propose the first model for quantitatively predicting the influence of 3D polycrystalline morphology on Coble creep deformation. This model was developed using a representative volume element (RVE). Two grain growth mechanisms, namely, grain boundary migration and grain boundary diffusion, were formulated considering the 3D data structure of a polycrystal and then superposed to simulate RVE deformation. The model was validated by comparison with the theoretical solution for Coble creep deformation under uniaxial loading conditions. The proposed model accurately reproduced the influences of grain size, applied stress, and temperature, thus demonstrating its validity. In addition, the influence of polycrystalline morphology was investigated by performing systematic numerical simulations. The model directly provided quantitative predictions of the performance of materials with arbitrary polycrystalline morphologies under any loading or temperature condition. Consequently, the proposed RVE model has the potential to serve as a basis for designing novel materials with resistance against high-temperature creep.