Cyclic and time dependence of superelastic properties such as critical stress for stress-induced martensite (σ<sub>SIM</sub>),
irrecoverable strain levels, and stress hysteresis are crucial parameters to ensure stable operation in applications of shape
memory alloys. In our studies on titanium-niobium shape memory alloys that have undergone various thermo-mechanical
processes, declines in both σ<sub>SIM</sub> and stress hysteresis with increasing cycle number were observed. More
surprisingly, aging treatment at room temperature following cycling produced stress-strain behavior very similar to
behavior of samples prior to cyclic deformation, and irrecoverable strain levels did not increase monotonically with
increasing cycle number. Lowest irrecoverable strain levels and smallest evolution in the superelastic behavior were
found in precipitated cold rolled or processed specimen by equal channel angular extrusion.