Thermodynamic and structural characterization of high- and low-temperature nitinol

Interest in micro actuators using Shape Memory Alloy (SMA) has increased as the research and development of micro and precision machinery have become active. However, no detailed studies of the thermodynamic properties of Nitinol alloy have been carried out yet. The thermal properties of high-temperature and low-temperature Nitinol SMAs were evaluated by using a differential scanning calorimeter (DSC) in the temperature range between -60 and 200 degrees C. The crystallographic structure was investigated by using X-ray diffraction (XRD). The storage and loss modulus of the SMA were measured by using a dynamic mechanical analyzer (DMA) as a function of frequency and temperature. The effects of frequency on the damping capacity have been systematically investigated in the cooling and heating process. Such frequency and temperature changes also significantly influenced the damping behavior of the SMA.