Experimental Investigation on Rate Dependence of Thermomechanical Response in Superelastic NiTi Shape Memory Alloy

In this paper, we focus on thermomechanical response of superelastic NiTi SMA at different strain rates under uniaxial loading. In situ digital image correlation method is applied to measure the local strain of the specimen. The evolution of the transformation bands is tracked by a CCD camera and the temperature field is recorded by an infrared camera. We show that there exists a strong link among strain rate, average temperature evolution, and the mechanical behavior of the material. It is also observed in the experiments that with the increase in strain rate, the deformation modes of the material transform from localization modes to homogenous modes.