TiNi alloy superelasticity degradation under constrained strain conditions

The superelasticity degradation of the TiNi alloys has been investigated under long-term constrained strain conditions. The results show that the superelasticity of TiNi alloys is degraded by the parabola-like type with time, and the constrained strain is larger, the value of the degradation is higher. When the constrained strain is low, no obvious degradation is found. The amplitude of the superelasticity degradation can be markedly decreased by the treatment of the stress-strain cycling. The mechanism on superelasticity degradation of TiNi alloys is discussed based on the clarification of degradation regularity.