Quantitative phase field simulation of athermal ω transition in Ti-Mo alloys

The ω phase is an important metastable phase in metastable β titanium alloys due to its significant influence on the phase transition sequence, microstructure evolution and mechanical properties of the alloys. In the present work, a quantitative phase-field model has been developed to describe the microstructural evolution during the athermal β to ω phase transition based on exact solution of coherent elastic energy and couplings to Ti-Mo metastable thermodynamical database. While reflecting the essential physics of {111}_β collapse mechanism that leads to displacive transition, the modeling appropriately described the morphology, orientation and growth process of the athermal ω phase upon different quenching temperatures and Mo contents, which agree remarkably well with available experimental data. Present approach also nicely predicts a selective variant growth which observed in the experiments.