A crystal plasticity model based on transition state theory

Abstract

A crystal plasticity model is developed whereby explicit connections with transition state theory and with the statistics of dislocation arrangements are simultaneously enforced. Leveraging theoretical work on diffraction line profile analysis, the model predicts the distribution of internal stress (or lattice strain) resulting from that of dislocations arrangements. In turn the internal stress distribution is used to predict the activation rate of dislocation unpinning while providing an explicit connection with experimental diffraction line broadening profiles. The newly developed model is implemented into an elastic viscoplastic self-consistent (EVPSC) framework and applied to the case of stainless steel. To clearly demonstrate the additional predictive capabilities of the model, the latter is used to predict the rate sensitivity, stress and strain relaxation, Bauschinger effect, temperature effects, and evolution of the mean and the standard deviation of the lattice strains. It is found that a single set of parameters provides good agreement between the predictions and the corresponding experiments.