Nanocrystalline metals represent a class of high-strength engineering materials with benefits for the electronics, aerospace, and automotive industries. However, their applications have been limited by their thermal instability and a lack of ductility. A strategy to address these limitations through thermo-mechanical treatment has been developed. This award supports fundamental research to understand the mechanisms that lead to improved ductility in nanocrystalline metals through this processing. The research will enable the development of sustainable bulk nanostructured metals with high strength and ductility to withstand application in extreme environments such as high temperatures and stresses. The work will also provide training to undergraduate and graduate students to meet the future needs of computationally-driven materials development.
The goal of the research supported by this award is to develop fundamental understanding of the cooperating and competing deformation mechanisms in grain boundary complexion-engineered nanocrystalline metals. It will elucidate their hierarchical contributions to mechanical performance and establish their connection with the disordered state of grain boundary complexion. This project will develop multi-scale modeling approaches, drawing from atomistic, mesoscale dynamics, and continuum mechanics simulations, utilizing kinetic Monte Carlo algorithm and finite element methods to bridge time and length scales. The direct connection of the model with in-situ neutron diffraction measurements will rigorously determine the dynamical interplay of deformation and grain boundary structural evolution. The findings of this project are expected to advance current knowledge of the underlying mechanisms controlling behavior in these materials, and to inform their coupling in the complex non-equilibrium metallic structures. The research results will provide guidance to complexion engineering for the design of mechanically-enhanced nanostructured metallic systems.
