Point defect species and concentrations in metastable Fe-C alloys were determined using density functional theory and a constrained free-energy functional. Carbon interstitials dominate unless Fe vacancies were in significant excess, whereas excess C caused greatly enhanced vacancy concentration. The predictions were open to experimental verification, and provided a baseline for rationalizing the complex microstructures seen in hardened and tempered steels, and in other materials created by, or subjected to, extreme environments.

Point Defect Concentrations in Metastable Fe-C Alloys. C.J.Först, J.Slycke, K.J.Van Vliet, S.Yip: Physical Review Letters, 2006, 96[17], 175501 (4pp)