In order to investigate the post yielding mechanical behaviors of SMA, the tension loading unloading tests were performed on the post yielding samples and superelastic samples at room temperature. Numbers of cycles, strain amplitudes and strain rates were considered to investigate their effects on the mechanical properties.The relationship between mechanical parameter and its corresponding loading factor was proposed.The experimental results show that these post yielding stress strain curves of SMA display no obvious superelastic plateau and have significantly residual strains after unloading completely.Compared to superelastic SMA, dissipated energy per unit volume of post yielding SMA decreases more than 40% and the peak stress increases about 90%.Plastic yielding strain has not much influence on ultimate stress while it has a strong influence on ultimate strain.It can be concluded that a small amount of plastic strain is helpful to obtain high recentering force of SMA based devices.Superelastic degradation and obvious residual strain of post yielding SMA should be considered in the SMA based devices design.
