J. Phys. IV France
Volume 112, October 2003
Page(s) 697 - 700

J. Phys. IV France
112 (2003) 697
DOI: 10.1051/jp4:2003978

Shape memory behavior associated with a two-stage R-phase transformation in Ti-50.9at%Ni alloy

J.I. Kim and S. Miyazaki

Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan

It was first found by the present authors that a two-stage R phase transformation appears in a Ti-50.9at%Ni alloy aged at 473K. The two-stage R phase transformation is characterized by two DSC peaks prior to the martensitic transformation during cooling (the first R phase transformation on cooling is denoted by R 1 and the second by R 2). Transformation temperatures of both the R-phases, R 1 and R 2, increase with increasing aging time. According to thermal cycling tests under various constant stresses, transformation strain of R 2 is larger than that of R 1, With increasing applied constant stress, the latter strain increases and the former one decreases. However, total strain of both R 1 and R 2 is almost constant irrespective of stress.

© EDP Sciences 2003