Linking multiscale materials modeling with experiment at the mesoscale using 3D X-ray microscopy

Ben Larson

Recently developed 3D X-ray microscopy techniques using high-brilliance synchrotron X ray microbeams at the Advanced Photon Source (APS) now provide non-destructive, submicron-resolution 3D measurements of local crystal structure, lattice orientation, and strain tensors in single crystal and polycrystalline materials. This capability provides an unprecedented opportunity to directly link experiment with multi-scale modeling of the microstructure and evolution of materials, a critical step for detailed testing the predictions of models at mesoscopic length scales (~ tenths of microns to hundreds of microns). In this presentation, the 3D x-ray microscopy technique will be illustrated using thermal grain growth in polycrystalline Al and dislocation density tensor measurements in thin, plastically deformed single crystal Si plates, and the direct link between 3D x-ray microscopy and computer modeling on mesoscopic length scales will be discussed in connection with deformation in metals. The ability to make detailed, quantitative comparisons between non-destructive, micron-resolution 3D x-ray microscopy measurements and finite element modeling will be demonstrated using 3D maps of local lattice rotations and local dislocation density tensors associated with nano/micro indentation induced deformation in Cu. Direct statistical based comparisons between 3D x-ray microscopy measurements and discrete dislocation calculations of deformation in homogeneously strained metals will be demonstrated as well, and discussed in connection with dislocation patterning on mesoscopic length scales. The ability of 3D x-ray microscopy to characterize strong dislocation patterning will be illustrated through direct, spatially resolved measurements of elastic strain in dislocation-rich cell walls and dislocation-poor cell interiors in deformed Cu.

Research at Oak Ridge National Laboratory sponsored by the DOE, Office of Science, Basic Energy Sciences, Division of Materials Research and Engineering; Operation of the APS is sponsored by the DOE, Office of Science, Office of Basic Energy Sciences.