ANISOTROPY OF SEVERAL PROPERTIES IN A POLYCRYSTALLINE FE-MN-SI BASED SHAPE-MEMORY ALLOY

The tensile properties, gamma<->epsilon transformation and shape recov ery have been related to the orientation of tensile axes i.e., along r olling direction(specimen 'A') and toward 45 degrees to the rolling di rection(specimen 'B') in a cold-rolled and then annealed Fe-15Mn-10Co- 5Cr-3Si alloy. It is revealed that the deformation modes of the specim ens 'A' and 'B' with respect to tensile axes are not the same; tensile deformation of the specimen 'A' is mainly achieved by slip, while tha t of the specimen 'B' is mainly governed by gamma-->epsilon transforma tion. The yield strengths of the specimens 'A' and 'B' are 569MPa and 745MPa, respectively. The reverse transformation temperature of the sp ecimen 'A' is much higher than that of the specimen 'B', and the shape recovery of the specimen 'B' is much larger than that of the specimen 'A'. The differences between those properties with tensile axes are d iscussed in association with texture developed in a cold-rolled and th en annealed Fe-15Mn-10Co-5Cr-3Si alloy.