Crystallization behavior of a Ti50Ni25Cu25 melt-spun ribbon

In the present study, the crystallization behavior of an as-spun Ti50Ni25Cu25 ribbon was investigated by using differential scanning calorimetry (DSC) method under continuous heating. After different crystallization processes, martensitic transformation of Ti50Ni25Cu25 ribbon was studied by using DSC, X-ray diffraction (XRD) and transmission electron microscopy (TEM). The crystallization temperature and the activation energy of the as-spun Ti50Ni25Cu25 ribbon were determined. A two-stage martensitic transformation was found after crystallized under different heating rates. For the transformation at higher temperature side, no obvious change with the heating rate was observed. For the transformation at lower temperature side, the transformation temperatures/hysteresis first decreased/increased with decreasing the heating rates and then quickly reached to a stable level. The transformation behavior is attributed to a combined effect of the inhomogeneous microstructure and the precipitation. (c) 2006 Elsevier B.V. All rights reserved.