Molecular dynamics study on the shear strain induced martensite-like transformation between rutile and α-PbO2 phase of titanium dioxide

Abstract

The martensitic-like transformation from rutile to α-PbO2 phase and its inverse phase transformation induced by shear strain were studied with molecular dynamics for titanium dioxide. After the strain exceeds 20.5% for the rutile phase, the martensitic α-PbO2 phase precipitates on the habitual plane between the new phase and parent phases, and then the stripe-shaped regions of the martensitic phase emerge between the edge and the center of the rutile-phase region. The titanium ions on the {011}rut crystal plane in the local area have uneven shuffle along the [0–11]rut and its opposite crystal direction，which means the shearing movements of titanium ions result in martensitic-like transformation. During the transition from the bulk α-PbO2 phase to the rutile phase, our potential barrier without any shear stress is 325 meV/TiO2 at 550 °C which is easy to be overcome for transformation. During the phase transition from the α-PbO2 phase to the rutile phase under certain shear stress, the rutile twins cannot appear separately in whole regions.