Towards new experimentally validated crystal plasticity models for polycrystalline metals

Abstract

To enhance the current materials design paradigm, a vastly improved understanding of structure-property relationships across a wide range of material systems is required. Recent initiatives have highlighted the importance of using a synthesized approach of experiment and modeling to further elucidate these relationships. Numerical models should aim to robustly predict the effect of different microstructural features on material response, but certainly require validation against relevant experimental data, ideally on several different length scales. With this in mind, experimental in-plane deformation maps as a tool for mesoscale calibration is presented. First, an investigation of the errors associated with experimental strain maps from Digital Image Correlation (DIC) and methods for optimizing experimental and numerical protocols to reduce uncertainty are presented. Second, a method to employ in-plane strain maps in calibrating a high-order numerical model is presented, highlighting the ability of the experimental dataset to further reduce the parameter space determined from experimental macroscopic load-displacement data. Lastly, a new, microstructurally-sensitive creep damage model is proposed and employed in a finite-element framework, and shows excellent agreement with experimental data, especially in the tertiary creep regime.