| AVS 58th Annual International Symposium and Exhibition | |
| Energy Frontiers Focus Topic | Friday Sessions |
| Session EN+AC-FrM |
| Session: | Materials Challenges for Nuclear Energy |
| Presenter: | G. Malcolm Stocks, Oak Ridge National Laboratory |
| Authors: | G.M. Stocks, Oak Ridge National Laboratory B.C. Larson, Oak Ridge National Laboratory |
| Correspondent: | Click to Email |
The extent to which the collective effects of defects can be manipulated and controlled yields the combination of structural materials properties – strength, toughness, and resistance to degradation in extreme chemical and radiation environments. In this presentation I shall outline the scope of studies of the fundamental physics of dislocations and radiation-induced displacement cascades being conducted within the Center for Defect Physics (CDP) at Oak Ridge National Laboratory and its partner institutions. Within the CDP, the focus is on the quantitative measurement and direct quantum simulation of defects at the level of unit dislocation and cascade events. For dislocation interactions, the focus is on high-spatial-resolution techniques such as 3D X-ray microscopy and convergent beam electron diffraction, which measure the local strains/stresses near isolated defects directly and thereby quantify the interactions and dynamics of defects in the bulk. For displacement cascades, the focus is on quantitative measurement of the formation and time evolution of energetic-ion-induced atomic displacement cascades using ultrahigh-resolution time-resolved X-ray diffuse scattering measurements made possible by the ultrahigh brilliance of femtosecond X-ray pulses produced at the Linac Coherent Light Source (LCLS) and the time-averaged brilliance of the Advanced Photon Source (APS). Theoretically, the focus is on developing high-fidelity models that treat spin and ion dynamics on an equal footing and to address system sizes and time scales commensurate with experiments. I will outline early progress with respect to addressing the feasibility of experimentally observing unit events and on developing ab initio electronic structure based theories of combined atomistic and spin dynamics. For the latter, I will show preliminary results for Fe that address the importance of the disruption of the magnetic state of Fe caused by the introduction of defects such as dislocations and displacement cascades that are based on large scale (~10,000 atom) models and order-N electronic structure methods.
Work supported by the “Center for Defect Physics in Structural Materials” which is a Department of Energy, Office of Science, Energy Frontier Research Center (EFRC).