How do atoms jump in ordered alloys? the model system Fe−Al

Summary Our aim is to reveal the elementary diffusion jump of Fe atoms in ordered Fe−Al single crystals (Fe contents 50.5, 55, 66 and 75 at.%) by comparing results from quasi-elastic M?ssbauer spectroscopy at⁵⁷Fe with results from other methods. The mechanism obviously follows one and the same logics irrespective of the alloy composition: Fe atoms jump into second or third nearest-neighbour sites on their own sublattice via the lying-between antistructure site on the Al sublattice. Since the disorder increases with increasing Fe concentration, the residence time of Fe atoms on the antistructure sites increases at the same time. Paper presented at ICAME-95, Rimini, 10–16 September 1995.