K.N. Lin

Damping characteristics of the Ti-rich TiNi melt-spun ribbon measured by using a dynamic mechanical analyzer

Damping characteristics of melt-spun Ti51Ni49 ribbons are investigated by using a dynamic mechanical analyzer (DMA). The as-spun Ti51Ni49 ribbons are crystalline and possess a uniform grain size distribution with an average diameter of 3 μm. The DMA results reveal that the tan δ value of the martensitic transformation peak increases with an increase in the temperature rate and applied deformation amplitude but decreases with an increase in the deformation frequency. Compared to amorphous or crystallized Ti50Ni25Cu25 melt-spun ribbons, the as-spun Ti51Ni49 ribbon was found to have a higher damping capacity during martensitic transformation when DMA tests were conducted at a cooling rate of 3 °C min−1 and a deformation frequency of 10 Hz. Besides, the as-spun Ti51Ni49 ribbon also exhibits a much higher inherent internal friction than bulk Ti50Ni50 or Ti51Ni39Cu10 shape memory alloys under isothermal conditions. The Ti51Ni49 melt-spun ribbon does not exhibit a relaxation peak, which is usually obtained in bulk Ti–Ni-based alloys or crystallized Ti50Ni25Cu25 melt-spun ribbons at about −75 °C in the DMA tan δ curve.