Martensitic transformation in Ti-rich Ti-Pd shape memory alloys

Abstract

A systematic study on martensitic transformation in Ti-rich Ti-Pd alloys has been carried out using differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The alloys quenched from the single region of B2 parent phase show a successive transformation during DSC measurement. On the other hand, the furnace-cooled alloys show a single transformation. The successive transformation behavior is closely related to the formation of fine Ti2Pd precipitates with C11b-type structure during transformation cycle. The first peak on DSC heating curve is attributable to the reverse martensitic transformation of the TiPd matrix, while the second one is due to the reverse martensitic transformation in local regions around the Ti2Pd precipitates where Pd concentration is higher than that in matrix. Morphological characteristics of the precipitate are also discussed.