Effects of crystallization temperature on the stress of NiTi thin films

We report the effects of crystallization temperature on the phase transformation behavior of NiTi thin films. With increasing crystallization temperature, the film stress during phase transformations drops sharply. Smaller grains were found as crystallization temperatures increased. These data suggest that, along with thermal stress, microstructure contributes to the phase transformation behavior, whereby smaller grains may suppress the conversion to martensite. This study illuminates the connection between processing, microstructure and phase transformation behavior for these technologically important materials.