R-phase transition and related mechanical properties controlled by low-temperature aging treatment in a Ti-50.8 at.% Ni thin wire

A cold-drawn Ti-50.8 at.% Ni wire was annealed at 600 degrees C for 30 min, followed by aging at 250 degrees C for different times. A microstructure with small grains and nanoscaled precipitates was obtained. The thermally induced martensite transformation is suppressed in the samples aged for 4 h or longer, leaving a one-stage R-phase transition between -150 and +150 degrees C. The transformation behavior, work output and recovery stress associated with the R-phase transition are presented. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.