Shape memory behaviour of Ti51.5Ni(48.5−x)Cux (x = 23.4-37.3) thin films with submicron grain sizes

►Ti51.5Ni48.5−xCux (x > 27) thin films show a perfect shape memory effect under 1 GPa. ►This improvement was attributed to their fine grain sizes (<500 nm). ►The films show characteristic shape memory behaviour owing to their fine grains. ►The effect of grain size was discussed on the basis of their martensite structure.