INTERSTITIAL HYDROGEN IN BCC BINARY-ALLOYS - SITE OCCUPANCIES AND TRANSITION-PROBABILITIES

The nature of interstitial sites, their spatial correlations as well a s their occupation probabilities by H (or D) have been investigated in random bce binary alloys. Sites of both octahedral and tetrahedral ty pes have been taken into account assuming they were distinguishable on e another on the basis of either the chemical composition of their fir st shell of neigbouring atoms or of the distribution of the two metall ic species within this shell. Short-range repulsive interactions among H atoms have been accounted for in terms of the hard core model and e xpressions have been derived for the so-called selective blocking fact ors. The results of calculations have been used to predict the occurre nce of anelastic relaxations due to H. A comparison of the theoretical predictions with experimental data available in the literature is pre sented.