9703281 Giannuzzi The goal of this CAREER research grant is to determine the effects of impurity grain boundary segregation on grain boundary diffusion. Attention is given to the effects of segregating atoms on heterodiffusion along low angle, high angle, and special copper twist grain boundaries, comparing heterodiffusion along unsegregated and segregated twist boundaries. Grain boundary diffusion of a solute is assessed in the presence of impurity segregants at the same temperatures used for the segregation experiments. Systematic evaluation of segregation composition, grain boundary diffusion lengths, and grain boundary structure is performed as a function of the annealing conditions. Experimental and theoretical approaches are employed to model enhancement or reduction of grain boundary diffusion due to the segregating impurity atoms. A primary goal of the CAREER education component of the program is to develop innovative teaching methods, while incorporating recent research findings into the classroom in the Materials Science and Engineering discipline. Multimedia and computer usage is planned for videotaped and live interactive classroom demonstrations. Computer software demonstrations and digital image computer analyses are employed. The effort includes mentoring undergraduates and exposing them to research projects, curriculum development, and community outreach. %%% This research is significant because identification of the mechanisms of impurity segregation effects on grain boundary diffusion will assist in the processing of materials with specific grain boundary properties. Ultimately, grain boundary engineering could be performed to either enhance or minimize a particular solid-state reaction. ***
