Microstructure of a rapidly solidified Ti75Ni25 alloy by melt-spinning process

A metastable crystalline Ti75Ni25 alloy in ribbon form is obtained by rapid solidification process. With the control of melt-spinning parameters different microstructures are formed, pointing to complex solidification effects in samples. The microstructural evolution as a function of cooling rate is explored using transmission electron microscopy. Temperatures of phase transitions are determined by different DSC analyses. X-ray diffraction patterns from the “disc side” and “air side” of the ribbon are analyzed to determine the difference in the phase composition. The correlation between cooling rates and the nature of solidification through the ribbon thickness as reflected in various microstructures is explained.