Mechanisms of grain boundary diffusion in intermetallic compounds

Atomic topological and chemical orders appearing at contact of two grains of an intermetallic compound are analyzed within the presentations of high-dimensional crystallography. It was shown that the anti-structure-like defects are possible to introduce for grain boundary material. The grain boundary diffusivity of intermetallic compounds is suggested to be governed by such defects. AB(3) intermetallic compounds with L1(2) structure and AB intermetallics with B2 structure are treated. Probable application of the model under consideration to grain boundary self-diffusion in Ni(3)Al is examined.