INFLUENCE OF ALFA MARTENSITE ON SHAPE-MEMORY IN FE-MN-BASED ALLOYS

An Fe-16Mn-6Si alloy exhibits a good one-way and a little two-way shap e memories by the stress induced gamma --> epsilon martensitic transfo rmation and its reversion on heating and cyclic thermal gamma reversib le arrow epsilon transformations, respectively. An intrusion of small amount of alpha' martensite at the initial shape change is not found t o deteriorate the one-way memory and rather enhance the two-way memory . The two Fe-Mn-C alloys are also examined and their inferior shape me mory is considered not due to the influence of alpha' martensite.