Modeling of the tension-compression asymmetry reduction of ECAPed Mg-3Al-1Zn through grain fragmentation

Abstract

In this work, a physically based model accounting for grain-to-grain interaction and grain refinement mechanisms is proposed to predict the anisotropic mechanical response and the texture evolution in ECAPed Mg-3Al-1Zn. The proposed model couples two approaches: crystal plasticity (CP), including twinning, and continuum dislocation dynamics (CDD). A grain refinement mechanism is also integrated into the model in order to predict the formation of refined grains during severe plastic deformation. A robust parameter identification method is proposed, in which experimentally reported process parameters are calibrated to fit the simulated mechanical behavior, texture evolution, and deformation systems-related activities. The anisotropic behavior evolution of the Mg-3Al-1Zn hot-rolled plate is examined by predicting the mechanical behavior, dislocation evolution, and slip/twin systems activities of the ECAPed material. The coupled CP-CDD model predicts grain size reduction with an average grain size which is in agreement with the experimentally measured values. Furthermore, the model generated textures are in accordance with those reported in the literature. Finally, a good agreement between the experimental and predicted true tensile stress–strain curves up to the ultimate tensile strength for both routes 4A and 4 K along extrusion and flow directions was found.