Effect of the heat treatment on the damping characteristics of the NiTi shape memory alloy

The structures and damping characteristics of the NiTi shape memory alloy using different heat treatment methods have been clarified by X-ray diffraction, differential scanning calorimetry, and damping analysis. Especially, we studied the dependence of damping characteristics on temperature, and the relations between vibration frequency and the transformation of the material. The results show that the structure of the alloy with slow cooling consists of large amounts of the M and R phases, and the Ni-richer Ti3Ni4, so that the damping level of the alloy is higher and produce a low frequency damping peak in the temperature area corresponding to the M → R reverse transformation in the reheating process. It is of technological importance.