The phase stability of ε-Fe alloys

Abstract

The hexagonal close packed ε-phase of Fe, which is of particular interest in the study of shape memory effects in some Fe-based alloys, can be stabilized in pure Fe under a pressure of about 11 GPa. Also, Fe will be in the ε-phase in the absence of ferromagnetic correlations in the α-phase. Therefore, an alternative to applying pressure to stabilize the ε-phase is to destroy the long range ferromagnetic ordering in α-Fe by alloying appropriate elements. In this study we discuss the relationship of the magnetic properties and the stability of the ε-phase in Fe and Fe-rich alloys with the aid of thermodynamical considerations and total energy calculations.