In the recent past, applications for nanoscale devices seem to be ever increasing creating a growing need to ensure reliability and predictive modeling capabilities. Consequently, this has motivated extensive research and discussion on the mechanical behavior and deformation mechanisms in nanocrystalline (NC) metals. As characteristic length scales shrink (< 100 nm), most NC metals exhibit
unique or different deformation mechanisms to those active in bulk and coarse-grained material counterparts. The purpose of this research is to investigate the nanoscale deformation processes through the development and application of a 3D PFDD model. The PF approach is centered on energy minimization; hence evolution of the PF variables has a direct dependence on system energetics. The total system energy is comprised of elastic contributions that take into consideration dislocation-dislocation interactions, interactions with applied stress, and a generalized stacking fault (SF) energy term. In this case, the 3D PFDD model can be informed directly by atomistic simulations in order to incorporate a dependence on the entire material g-surface as opposed to only one or two SF energies. Additionally, this third energy term can be used to account for the directional motion of dislocations as in body-centered cubic (bcc) metals, where edge dislocations are easier to move than screw dislocations due to differences in the dislocation core structure. In this talk, the PFDD approach will be presented and recent results addressing dislocation transmission through interfaces along with other extensions will be discussed.
Dr. Abigail Hunter
Currently a staff scientist at Los Alamos National Laboratory (LANL) in the Computational Physics (XCP) Division. She earned a Ph.D. in Mechanical Engineering (ME) from Purdue University in 2011, and a B.S. degree in ME from the University of Utah in 2006. Following her Ph.D., she joined LANL as a postdoctoral research associate in 2011 in the Lagrangian Codes Group (XCP-1) and converted to a staff scientist in 2012. She moved to the Materials and Physical Data Group (XCP-5) in 2019. She is currently the Deputy Director for the Institute of Materials Science at LANL and an Associate Editor of the Journal of Engineering Materials and Technology. In 2020, she received the Alum of the Year Award from the ME department at the University of Utah in recognition for outstanding achievements in ME and service to the community. In 2019 she was nationally recognized as a recipient of the Presidential Early Career Award for Scientists and Engineers for work developing and implementing models addressing brittle damage and dislocation dynamics in metals, which are two capabilities designed to address questions concerning advanced manufacturing of new materials. Her research interests include modeling the strength and damage of metals at both the meso- and macro-scales, with specific interest in connections between microstructure, dislocation-based deformation behaviors, and overall material response.