A cluster-type grain interaction deformation texture model accounting for twinning-induced texture and strain-hardening evolution: Application to magnesium alloys

Abstract

Twinning plays two important roles in deformation texture evolution: it reorients the twinned volume of a grain discontinuously, thus causing a texture change; and the lamellar structure of twins reduces the mean free path for dislocation slip, which effectively promotes work-hardening. To correctly predict the texture evolution of materials in which twinning plays an important role, both effects of deformation twinning must be taken into consideration. In the current work, both effects are accounted for in the cluster-type deformation texture grain interaction (GIA) model. Slip-induced strain-hardening was considered by employing a one-parameter hardening model, which calculates the flow stress evolution for each slip system. Twinning-induced strain-hardening was incorporated into the model by treating twin lamellae as ellipsoidal inclusions formed by alternating layers of twin and matrix domains. The twin–matrix interfaces provide barriers and define a directional mean free path for the propagations of subsequent slip or further twinning. The modified GIA model is called the GIA-TW-HD model. It was applied to predict the deformation behavior and texture evolution of Mg alloy AZ31 at 100°C. The predicted texture evolution as well as strain-hardening curves were compared with experimental results. Overall good agreement between simulation and experiment was obtained.