J. Phys. IV France
Volume 112, October 2003
Page(s) 1043 - 1046

J. Phys. IV France
112 (2003) 1043
DOI: 10.1051/jp4:20031060

Phase transformations in Pd-and Ni-rich Ti-Pd-Ni alloys

M. Nagasako and M. Nishida

Kumamoto University, Graduate Schoof of Science and Technology, 2-39-1 Kurokami, Kumamoto 860-8555, Japan

It has been found that Ti 45Pd 45Ni 10 alloy shows peculiar phase transformations. Upon heating in DSC measurement, an endothermic reaction occurs firstly around 373 K, which corresponds to the reverse martensitic transformation from B19 to B2 structure. Subsequently, a pair of exothermic and endothermic peaks is observed from 550 to 740 K, which is due to the appearance and disappearance of new order phase with long period stacking structure. One of characteristic feature in electron diffraction pattern of the new phase is superlattice spots as 1/8 position in the row of reflections of 111 $_{\rm B2}$*. Finally, an exothermic reaction which corresponds to the formation of Ti 2(PdNi) 3 phase is detected around 850 K. More interesting phenomenon, which is the parent phase stabilization with low temperature aging below 500 K, is discovered. The $\omega$-like diffuse reflections with rather strong intensity are observed in electron diffraction patterns taken from the stabilized B2 phase. Morphological and crystallographic aspects of the new order phase are also discussed.

© EDP Sciences 2003