Influence of cooling in liquid nitrogen on shape memory effect of CuZnAlMnNi alloy

Shape memory effect (SME) of a CuZnAlMnNi alloy after cooling in liquid nitrogen was investigated. It was found that the SME decreases when the quenched alloy is subjected to further cooling in liquid nitrogen. The original substructure of stacking faults becomes confused, and the order degree of the alloy reduces after further cooling. The confused stacking faults are easy to evolve into dislocations during training, which inhibits the motion of phase boundaries during the forward and reverse martensitic transformations and finally results in the decrement of SME.