Point defect-solute interactions in metals

As for a molecule in free space, the calculation of the point defect-solute interaction energy as a function of separation is usefully discussed in terms of regimes 1 and 2 characterized by (1) weak interaction and (2) electronic redistribution. Regime 1 is appropriate for simple impurities such as Zn, Ga and Ge interacting with vacancies in Al. Both electron theory and experiment yield small impurity-vacancy interaction energies in this case. Interstitial impurity-vacancy interactions probably fall in regime 2 and the theory is not well developed. However, the knowledge the authors have on diffusion by Miller pairs, and on interstitial H in Al, is reviewed. A brief discussion on self interstitial-impurity complexes is also included. (Auth.)