Evolution of microstructure and thermomechanical properties during superelastic compression cycling in Cu–Al–Ni single crystals

The aim of this work is to relate the macroscopic evolution of the compression superelastic effect in Cu–Al–Ni shape memory alloy single crystals with the evolution of the microstructure during cycling. The analysis has been carried out as a function of the number of cycles, the maximum reached deformation and the kind of induced martensite. Moreover, the new microstructure after mechanical cycling and the evolution of the thermal transformation have been also studied. The presence of two new families of dislocations created by different mechanisms has been observed and the influence of each one on the stress-induced and thermal transformations has been analyzed. In the samples where both kinds of dislocations are present at the same time, the observed behaviour is a combination of their effects in proportion to their density.