Microstructure and damping characteristics of Ti50Ni24.9Cu25Y0.1 shape memory alloy

The microstructure of annealed Ti50Ni24.9Cu25Y0.1 alloy was studied through X-ray diffraction (XRD) and transmission electron microscope (TEM) measurements. It has been shown that the microstructure was composed of the B19 martensite. The temperature, frequency and strain amplitude dependences of the internal friction (IF) in the Ti50Ni24.9Cu25Y0.1 alloy were investigated by dynamic mechanical analyzer (DMA), as well as differential scanning calorimetry (DSC) measurement. The DSC results indicated that only a stage of the phase transformation took place and yttrium (Y) solid-solution narrowed the transformation hysteresis. The IF kept a high value in the stage of martensitic phase and the phase transformation due to the addition of Y element during nonisothermal process. The isothermal internal friction curves were observed in our work.