FCC → FCT martensitic transformation in two-phase Mn–Cu alloys

Abstract

The fcc → fct martensitic transformation in Mn–Cu alloys, which contain two isomorphous fcc phases with different manganese contents, is considered. The influence of the ratio of contents of these phases, the phase dispersity, and the state of interphase boundaries on the development of the martensitic transformation in the volume of the alloys is described. As a result of these factors, the martensitic transformation can cover the entire volume of an alloy, including particles with the manganese content that is lower than the critical content required for the martensitic transformation to occur in single-phase solid solutions, and can take place only in manganese-rich particles. In the first case, a general tetragonal structure modulated with respect to lattice parameter c forms in the volume of a two-phase alloy.