An analysis was performed, using the statistical thermodynamic approach, of an increase in site vacancies in interstitial-substitutional solid solutions and of an experimentally observable manifestation of this effect in H-charged austenitic steel. It was concluded that the dissolution of interstitials led to an increase, in the equilibrium concentration of site vacancies, due to an increase in the entropy of the solid solution and to the energy which was expended on the injection of interstitial atoms. After H out-gassing, the vacancies became thermodynamically unstable and formed dislocation loops which could be detected by means of transmission electron microscopy.

V.G.Gavriljuk, V.N.Bugaev, J.N.Petrov, A.V.Tarasenko, B.Z.Yanchitski: Scripta Materialia, 1996, 34[6], 903-7