A Study of the Structural and Energy Properties of (210) and (130) Boundaries in Iron and an Fe–Cr Alloy

The structure and energy properties of symmetric tilt boundaries Σ5 (130)[001] and Σ5 (210)[001] in iron and low-concentration Fe–Cr alloys are investigated from first principles and by the molecular statistics method. It is shown that the boundary strongly changes the interplane distances. The sequence of multi-layer relaxation comprises damped oscillations, gradually decreasing into the grains. The energy for the replacement of iron with chromium atoms near the boundaries is lower than in pure iron. Our calculations indicate the tendency to accumulate Cr atoms and vacancies near the grain boundaries.