The Effect of Dynamic Strain Aging on Strengthening of AA5754 Aluminum Alloys: Theoretical and Numerical Approaches

A constitutive model for face-centered cubic structured materials considering the characteristics of dynamic strain aging and its effect on the material behaviors is developed by introducing an extra stress component. In the proposed model, the total stress is divided into athermal and thermal components. The former includes the additional term for dynamic strain aging. This term is conceptually inspired by the probabilistic nature of dynamic strain aging, and its derivation is micromechanics-based. Both athermal and thermal components are defined as a function of temperature, equivalent plastic strain, and equivalent plastic strain rate, because the occurrence and characteristics of dynamic strain aging are dependent on them. To evaluate the validity of the proposed model, two sets of experiments from different literature regarding AA5754 aluminum alloys are utilized. Although identical material parameter values are applied to the different experiments, the proposed model provides excellent quality result. A finite element solution for the proposed model is addressed additionally to further investigate the characteristics of dynamic strain aging. The numerical results are compared to the experiments and theoretical predictions for its validation. Lastly, the effect of dynamic strain aging on strain rate sensitivity is discussed.