Stress-induced reverse martensitic transformation in a Ti-51Ni (at%) alloy aged under uniaxial stress.

Ti-51Ni (at%) alloys including coherent precipitates of TiNi exhibits thermally-induced B2-R transformation. If the TiNi is formed under tensile stress, it orientates preferentially so that its habit plane becomes perpendicular to the tensile axis. In such specimens, stress-induced reverse R-B2 transformation is reported to occur. In the present study, the stress-induced reverse R-B2 transformation behavior was studied by infrared camera and in situ X-ray analysis. The infrared camera observation revealed that the temperature of the specimen decreases homogeneously by the application of tensile stress within the resolution of the camera. The in situ X-ray analysis revealed that stress-induced reverse R-B2 transformation and rearrangement of variants of the R-phase occurs simultaneously in the specimen.