Modeling of dynamic recrystallization texture in hot extruded Mg

Abstract

Because of the strong effect of texture on the properties of alloys, the evolution of texture during hot extrusion of Mg has been studied through experiments and simulations. For a better understanding of the texture evolution at high processing temperatures, the model based on viscoplastic formulation was extended to a cellular automaton procedure to consider the recrystallization mechanisms. Texture evolution was simulated for the basal, prismatic and pyramidal 2nd order slip systems. Twinning was not considered because no twins were observed in the microstructural investigation. In the experimental investigations, the samples were extruded to a strain of ε = 2.7 at different temperatures, namely 180 °C, 280 °C, and 380 °C. The microstructure, texture, and hardness were evaluated by optical and electron microscopy using EBSD, X-ray diffraction, and Vickers tests, respectively. The main textural components were identified for each deformation temperature. Based on the simulations, a mechanism for the formation of a specific component was proposed. It was found that the change in the main texture component depends not only on the critical resolved shear stress for a specific slip system but also on the recrystallization parameters. The vpsc model has been shown to predict only the deformation texture components because the temperature is accounted for in accordance with the critical resolved shear stress and rate sensitivity. These two parameters affect the slip system activity. The new model using the cellular automaton procedure, which covers recrystallization processes, produces textures that fall in line with the experimental results.