High temperature internal friction in Ni50.3Ti29.7Zr20 shape memory alloy

Abstract The internal friction at temperature up to 980 K in Ni 50.3 Ti 29.7 Zr 20 (at.%) high temperature shape memory alloy was investigated. A relaxation peak was observed at about 750 K for 0.1 Hz. Its activation parameters were determined, H act  = 1.82 ± 0.04 eV, τ 0  = 2.22 × 10 −12  s. Similar relaxation peak with the activation enthalpy of about H act  = 1.42 eV was observed in Ni Ti binary alloy at a slightly lower temperature. Alloying of Zr is found to increase the activation enthalpy of this relaxation. The mechanism of this relaxation was discussed based on a Zener relaxation related to the short-range diffusion of Ni.