Instability of cyclic stress-strain response in austenitic stainless steel single crystals

An austenitic stainless steel single crystal was cyclically deformed under plastic strain control. In order to investigate the instability of cyclic stress-strain response, standard deviations of stress and strain amplitudes in sequential cycles have been calculated throughout the cyclic deformation test. It is found that the standard deviations decreased with increasing cycles in the initial stage of fatigue. Such a successive decrease in the standard deviations is terminated at the cycle corresponding to the maximum value of the Bauschinger energy parameter. The instability of cyclic response appears to be associated with small-scale strain bursts.