Tensile and Fatigue Properties and Deformation Mechanisms of Twinning-Induced Plasticity Steels

With the development of automotive industry, it is necessary to develop advanced high-strength steels for the purpose of lightweight of car. Based on the systematic studies on the strengthening and toughening as well as fatigue design of the twinning-induced plasticity (TWIP) steels, the recent progress in this aspect is summarized and discussed. Among them, the strengthening and toughening mechanisms have been analyzed and further developed in terms of several influencing factors, including compositions, microstructure, strain rate and so on. Furthermore, the low-cycle and high-cycle fatigue behaviors and damage mechanisms were explored. For better understanding the intrinsic fatigue damage mechanism, a new low-cycle fatigue prediction model regarding the hysteresis loop energy during cyclic deformation was introduced. It is found that the energy damage model can well explain and evaluate the fatigue damage mechanism and predict the low-cycle fatigue life of the TWIP steels and other materials. Based on the new fatigue damage model, new TWIP steels with high service performance can be developed by adjusting their deformation and damage mechanisms rationally.