Abstract: The effect of pre-strain on phase transformation of TiNi shape memory alloy film was studied by differential scanning calorimeter measurement(DSC).Compared with undeformed TiNi film,the reverse transformation of pre-strained specimens was elevated to a higher temperature on the first heating,but martensite and reverse transformation on subsequent thermal cycles occurred at a lower temperature.The evolution of transformation behavior in pre-strained TiNi film was related to the change of elastic strain energy,irreversible energy and internal stress field.

Key words: shape memory alloy, TiNi film, pre-strain,