Constitutive modeling of flow stress and work hardening behavior while considering dynamic strain aging

The phenomenon of dynamic strain aging (DSA) occurs in many alloy systems and inevitably leads to variations in the flow stress and work hardening behavior. In this study, a modified constitutive relationship that takes into account DSA is proposed for modeling the flow stress and work hardening behavior of alloys. We theoretically show that the additional strengthening caused by DSA depends on the strain and strain rate at a given temperature. The contribution of DSA on flow stress and work hardening rate is clearly predicted by our model, which can account for as much as 9% and 14%, respectively. The modeling results agree well with those of experiments performed on an AlMg alloy that exhibits the DSA phenomenon. Finally, the intrinsic mechanism of DSA-induced strengthening on flow stress and work hardening rate is discussed. It is proposed to be that when the imposed strain or strain rate changes, the binding energy between the diffusing solute atmosphere at the dislocation core and the dislocations also changes, thus affecting the flow stress and work hardening rate during the deformation process. This study quantifies the influence of DSA on flow stress and work hardening rate during deformation, which can provide insight into the understanding of mechanical behavior of materials with DSA.