High temperature creep measurements in equiatomic Ni-Ti shape memory alloy

Abstract

High temperatures creep rates in equiatomic NiTi alloys at three different stress levels and at different temperatures have been measured. It was obtained that the creep rate can be well described by the Dorn equation with n=3. The activation energy of the effective diffusion coefficient, Dc (characterizing the Herring-Nabarro bulk creep) is Qc= 226 kJmole-1. From comparison of this value with the activation energy of Ni tracer diffusion (155 kJmol-1) it was concluded that the Ti is the slower component with high diffusion activation energy close to Q c. © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.