It was recalled that, whereas diffusion in pure metals and dilute alloys had been extensively investigated, and was reasonably well understood, relatively few systematic diffusion studies had been made of intermetallic compounds. The understanding of diffusion in intermetallics in terms of defect structures and diffusion mechanisms was expected to be more complicated than for metallic elements. The present review was devoted to the subject of binary intermetallics; especially the common B2, L12, D03, D019, L10 and cubic Laves-type structures. Some structural implications for diffusion in these materials were considered; including the Cu3Au rule. Diffusion phenomena in binary systems, such as self-diffusion, diffusion of foreign atoms, single-phase and multi- phase interdiffusion were described and illustrated by experimental examples. It was pointed out that the Darken-Manning equation, which was sometimes used to correlate the tracer diffusion of components with interdiffusion data, had limitations. The self-diffusion of components, which was the most basic diffusion process in solids, was reviewed for intermetallics with the above structures. Relevant factors, such as the crystal structure, degree of order, and temperature and composition dependences were illustrated. In a few cases, the diffusion of certain foreign elements was considered. Particular attention was paid to the current understanding of diffusion in terms of defect structures and atomic mechanisms. The review also included a summary of recent investigations of diffusion in the D03-type intermetallic compound, Fe3Si, of Ti self-diffusion in intermetallic compounds of the Ti-Al system, and of single-phase and multi-phase interdiffusion in intermetallics such as the cubic Laves phase, Co2Nb.

H.Mehrer: Materials Transactions, 1996, 37[6], 1259-80