Grain-boundary diffusion: an historical perspective

Abstract

About 60 years ago it was first realised that grain boundaries in crystalline solids were preferential pathways for diffusion, especially at relatively low temperatures. This paper traces the main developments in the field from its inception to the present day. Particular emphasis is placed on experimental methods and the interpretation of results therefrom. Although there has been considerable progress and many data have been accumulated, some fundamental aspects remain unresolved.