Strain hardening due to deformation twinning in (alpha)-titanium: Constitutive relations and crystalplasticity modeling

The mechanisms governing twin-induced strain hardening of high-purity (alpha)-titanium at room temperature were incorporated into constitutive laws to describe the evolution of both twin and slip resistance due to deformation twinning. The proposed equations were incorporated in a Taylor-type crystal plasticity model to predict mechanical behavior and texture evolution for different deformation paths. Model predictions for the overall stress–strain response and texture evolution compared well with the experimental results. Specifically, the model captured the three stages of strain hardening for uniaxial-compression and plane-strain-compression testing of (alpha)-titanium. In addition, predicted texture evolution due to the reorientation of twinned area showed excellent agreement with the observations. These findings proved the necessity of incorporating twinning and its associated hardening mechanisms in realistic constitutive descriptions to account for anisotropic strain-hardening behavior and texture evolution in materials that deform by both slip and twinning.