Effect of grain size and texture on superelasticity of Cu-Al-Mn-based shape memory alloys

The effect of texture and β grain size on the superelasticity (SE) in Cu-Al-Mn-based alloys was investigated by tensile testing. The SE strain increases with increasing relative grain size d/t (d: grain size and t: specimen thickness), which is explained as being due to a relaxation of the grain constraint in the polycrystalline specimens. On the other hand, Cu-Al-Mn-Ni alloy recrystallized after heavy cold-rolling in the fcc (α) + bcc (β) two-phase region showed a {112}<110> strong recrystallization texture. The SE strain depends on the testing direction on the textured sheet specimens, and the largest value of SE strain was obtained in the specimen tested along the direction of 45° from the rolling direction (RD).