Modeling inelastic behavior of magnesium alloys during cyclic loading–unloading

Abstract

The inelastic behavior presenting in magnesium alloys during cyclic loading–unloading have been investigated through the finite strain elastic viscoplastic self-consistent (EVPSC) model for polycrystals (EVPSC-TDT), which has been updated by implementing the twinning and de-twinning (TDT) model. Corresponding to the existing experiments of extruded bars of Mg alloys, we constructed the extruded bars of magnesium alloys with different initial textures in our simulations to study the effects of initial textures and deformation processes (tension and compression) on inelastic behavior during cyclic loading and unloading. Taking the advantage of numerical modeling, the evolution of the instantaneous gradients, the activity of the deformation mechanisms and the evolution of twin volume fraction are characterized to interpret the inelastic behavior. We found that the alternation of deformation mechanisms corresponds to the inelastic behavior; in particular, the inelastic behavior becomes more pronounced when twinning and de-twinning are activated. Thus, a strong extrusion texture reduces the hysteresis loops of the loading–unloading cycle under uniaxial tension, while magnifies the inelastic behavior under uniaxial compression, because twinning and de-twinning are more active for extrude bars with the strong extrusion texture under compression. The simulated results are in agreement with the available experimental observations.