An analytical relaxation model of plasticity is proposed for predicting the deformation characteristics of cyclically stabilized materials. The model is modified for cyclic deformation conditions and involves the determination of the structural-temporal and relaxation characteristics of the material. It is shown that the earlier developed relaxation model of plastic deformation for single loading can predict the rapid relaxation of plastic strains (stabilization effect). The phenomenological model results agree well with experimental data for steel DP500 as well as for steel 50 subjected to heat and thermomechanical treatments under unidirectional cyclic deformation. The characteristic times of structured and nanostructured steel 50 are estimated and compared. It is shown that the time sensitivity factor of the material included in the relaxation model of plasticity can take into account the material processing method.