Manganese-induced ordering in the α-(Al-Mn-Fe-Si) approximant phase

Abstract

Abstract We report a transmission electron microscopy study of α-(Al-Mn-Fe-Si) phases, isostructural to the α-(Al-Mn-Si) approximant phase. Selected-area diffraction patterns exhibit a noticeable diffuse scattering due to short-range ordering. We show that the ordering effect is reinforced by the Mn additions. This diffuse scattering can be described by a surface close to a polyhedron in the reciprocal space. We interpret the shape of this surface as a consequence of the ordering of two types of entities (Mackay icosahedra) along the (111) directions.