Investigation of early stage deformation mechanisms in a metastable β titanium alloy showing combined twinning-induced plasticity and transformation-induced plasticity effects

Sun, F. [Chimie-ParisTech, France] Zhang, J.Y. [Chimie-ParisTech, France] Marteleur, Matthieu [UCL] Gloriant, T. [Institut des Sciences chimiques de Rennes, France] Vermaut, P. [ESRF, Grenoble, France] Laillé, D. [Institut des Sciences chimiques de Rennes, France] Castany, P. [Institut des Sciences chimiques de Rennes, France] Curfs, C. [ESRF, Grenoble, France] Jacques, Pascal [UCL] Prima, F. [Chimie-ParisTech, France] et al.[show all]

As expected from the alloy design procedure, combined twinning-induced plasticity and transformation-induced plasticity effects are activated in a metastable β Ti–12 wt.% Mo alloy. In situ synchrotron X-ray diffraction, electron backscatter diffraction and transmission electron microscopy observations were carried out to investigate the deformation mechanisms and microstructure evolution sequence. In the early deformation stage, primary strain/stress-induced phase transformations (β → ω and β → α″) and primary mechanical twinning ({3 3 2}〈1 1 3〉 and {1 1 2}〈1 1 1〉) are activated simultaneously. Secondary martensitic phase transformation and secondary mechanical twinning are then triggered in the twinned β zones. The {3 3 2}〈1 1 3〉 twinning and the subsequent secondary mechanisms dominate the early-stage deformation process. The evolution of the deformation microstructure results in a high strain-hardening rate (∼2 GPa), bringing about high tensile strength (∼1 GPa) and large uniform elongation (>0.38).