Enhancement of superelasticity in Cu-Al-Mn-Ni shape-memory alloys by texture control

A significant improvement in the degree of superelasticity in Cu-Al-Mn ductile polycrystalline alloys has been achieved through the addition of Ni and control of the recrystallization texture by thermomechanical processing, which contain the annealing in the fcc (α) + bcc (β) two-phase region, followed by heavy cold reductions of over 60 pct. The addition of Ni to the Cu-Al-Mn alloys shows a drastic effect on the formation of the strong {112} 〈110〉 recrystallization texture. Superelastic strains on the order of 7 pct, 3 times larger than those in other Cu-based shape-memory alloys (SMAs), have been realized in the textured Cu-Al-Mn-Ni alloys. The superelastic strains obtainable in the textured Cu-based SMAs are on a par with those attainable in Ni-Ti-based alloys.