Microstructure and beta grain growth behavior of Ti–Mo alloys solution treated

The microstructure and grain growth kinetics of Ti–Mo binary alloys in the β phase have been studied. The results show that the phase composition and grain growth kinetics of the solution-treated alloys are sensitive to Mo content. Ti–1Mo alloy mainly containes hexagonal α phase, while Ti–4Mo alloy is composed of dominated β phase and some inner acicular α′. When Mo content increases to 10 wt% or higher, the retained β phase becomes the only phase. The β grain size is not only related to temperature and solution time, but also relates to Mo content. The grain growth rate of Ti–4Mo alloy during solution treatment is much faster than that of Ti–20Mo alloy, and the time exponent 0.42 of the Ti–4Mo alloy is higher than that of Ti–20Mo alloy due to the low dislocation density. However, the grain-growth activation energy of Ti–20Mo alloy is 272.16 kJ/mol, which is much higher than that of Ti–4Mo alloy, due to the “solute drag effect” of Mo. The room-temperature strength and plasticity of Ti–Mo alloys increase with the increasing of Mo content and decreasing of grain size.