DIFFUSION IN ORDERED ALLOYS AND INTERMETALLIC COMPOUNDS

Diffusion in binary ordered alloys has been treated using the pair-app roximation of the Path Probability Method (PPM) based on an atomistic model. The effect of the atomic interaction on the ordering behavior a nd its influence on transport properties have been clarified. Composit ional dependence of both the intrinsic diffusion and interdiffusion co efficients, correlation factor and thermodynamic factor agree very wel l with the Monte Carlo simulation. The calculated properties also show qualitative agreement with the experimental data on diffusivity, acti vity and creep in the NiAl system.