The incorporation of ω particles during growing or coarsening process in metastable β titanium alloy

The ω particle in metastable β titanium alloys is found in nano-scale size. Furthermore, the driving force distributes homogeneously in the parent phase and is too small to drive the ω particle bigger, which may cause the homogeneous nucleation and small growth rate. However, the incorporation of ω particles may happen during the growing and coarsening process,which may lead to the redistribution of ω particles. In this study, according to the simulation model and local free energy calculation, the incorporation and redistribution behaviors of w particles are investigated. This research shows that the incorporation of ω particles is determined by the competition between interfacial energy and coherent elastic energy, which associates with the morphology of ω particles and the energy distribution around them. The ω phase is in the shape of truncated ellipsoid by the planes at both ends of the major axis (along 〈111〉 direction). By the minimizing action of free energy, the new direction of the particles arrangement deviates from 〈111〉 crystal orientation about 10°. Moreover, the particle incorporation and redistribution phenomenon are widely found in quenching and aging processes. The calculation results accord well with experimental results.