Crystal structure of a long-period ordered phase in Fe-C martensite and computer simulation of its electron diffraction patterns

Different structure models of a long-period ordered phase in Fe-C martensite formed during aging have been checked by computer simulation of electron diffraction (ED) patterns based on these models. The results showed that the simulated ED pattern of γ′-Fe_xC(II) model proposed by the present authors is in good agreement with experimentally observed ED pattern. It was also confirmed that the incommensurate superperiod stems from the coexistence of several γ′-Fe_xC(II) phases with different superperiods. The Fe₁₄₄C₂₄(Fe₆C) model proposed by Uwakweh et al. generated ED patterns remarkably different from the experimental ones.