Crystal Structure of New Approximant Phase in Al-Fe-V-Si System

Abstract

AbstractA model proposed for the atomic structure of the new hexagonal Al-Fe(V)-Si phase which was found in rapidly solidified Al-Fe(V)-Si alloys is discussed in terms of relation this phase to approximants. The structure of this new phase was described as hexagonal packing of double Mackay icosahedral units similar to those of which the cubic α-(AlFeSi) approximant phase is built up. On the basis of this model the experimental high resolution electron microscopic (HREM) images of the hexagonal phase were successfully interpreted. Like the á phase this structure is characterized by the local icosahedral ordering and can be regarded as an approximant.