Grain boundary diffusion: recent progress and future research

Grain boundary (GB) diffusion often controls the evolution of structure and properties of engineering materials at elevated temperatures. A knowledge of diffusion characteristics of GBs and deep fundamental understanding of t his phenomenon are critical to many materials applications. In this paper w e give an overview of boundary diffusion theory with emphasis on the interp retation of concentration profiles measured in diffusion experiments. We co nsider the most important situations encountered in boundary diffusion expe riments, such as diffusion in the B and C regimes and diffusion in the pres ence of segregation. We also discuss the recent progress in the atomistic i nterpretation of GB diffusion. We conclude with an outlook for future resea rch in this area. (C) 1999 Elsevier Science S.A. All rights reserved.