Grain Stability in Nanostructured Metals

University Of California-San Diego, La Jolla CA

Investigators

Abstract

Grain Stability in Nanostructured Metals Abstract This project is concerned with fundamental studies of the stability of ultra-fine and nanstructured grains in metals, both with face centered cubic and hexagonal close packed crystal structures, and in metals that contain either, or both, nano-sized grains or nano-sized twins. Nano-twinned copper and nano-grain size titanium will be studied using a variety of methods, including micro-indentation, dynamic deformation, and micro-tensile testing. The dynamic deformation in titanium is designed specifically to document the tendency of titanium grain boundaries to migrate leading to instability of the ultra-fine grain structure. Complimentary theoretical studies will include atomistic simulation using our newly developed finite temperature quasi-continuum method. In these studies simulations of the deformation of nano-sized twinned structures will be performed to explore the interaction of dislocations with twins and the potential motion (that is the instability) of twin boundaries. Educational activities include the training of graduate students and undergraduate students chosen from under represented groups; two such undergraduate students are already working on directly related topics. A web site is established to rapidly disseminate novel results and to act as a repository for others to add newly obtained data. We are participating in a program called ?Bridges to the Future?, a San Diego program designed to transition the careers of under represented minorities into science. We also participate in the California State Summer School for Mathematics and Science (COSMOS) aimed at 9th-12th graders who demonstrate interest in math and science. Our focus in this will be nanotechnology.