Using high energy diffraction microscopy to assess a model for microstructural sensitivity in spall response

[摘要] We present results from a modeling effort that employs detailed non-destructive three-dimensional microstructure data obtained from X-ray based High Energy Diffraction Microscopy (HEDM) experiments. The emphasis is on validating models that capture microstructural sensitivities so that these models can then be employed in rapid certification procedures. By focusing validation efforts on models that connect directly to experimentally measurable features of the microstructure, we can then build confidence in use of the models for components prepared under different processing routes, with different chemical compositions and attendant impurity distributions, or subjected to different loading conditions. The computational model makes use of a crystal mechanics based constitutive model that includes porosity evolution. The formulation includes nucleation behavior that is fully integrated into a robust numerical procedure, enhancing capabilities for modeling small length scales at which nucleation site potency and volume fraction are more variable. Three-dimensional experimental data are available both pre-shot and post-shot from the same volume of impact-loaded copper. Crystal lattice orientation and porosity data are obtained, respectively, from near-field HEDM and tomography techniques. The availability of such data serves as a primary motivation for the model effort at the microstructural scale.

[发布机构] Lawrence Livermore National Laboratory, Livermore; CA; 94551, United States^1;Los Alamos National Laboratory, Los Alamos; NM; 87545, United States^2

[关键词] Chemical compositions;Diffraction microscopy;Impurity distribution;Lattice orientations;Nucleation behavior;Numerical procedures;Porosity evolutions;Three-dimensional microstructures