Studies on omega Phase Formation in Ti-Mo Alloys Using Synchrotron XRD

摘要

This paper presents the results of synchrotron based x-ray diffraction experiments in Ti-Mo alloys, to examine the formation of metastable omega phase, which could not be detected using conventional XRD (x-ray diffraction). The study confirms the formation of non-equilibrium, athermal omega phase on quenching the beta phase at different cooling rates in Ti-15 wt% Mo alloy and its absence in Ti-25 wt% Mo alloy. On ageing, isothermal omega is observed in Ti-15 wt% Mo. However, increase in amount of Mo stabilises the bcc beta phase in Ti-25 wt% Mo alloy, leading to absence of omega phase, despite ageing in the alpha + beta field. The threshold concentration of Mo to stabilize the beta phase in the alloy is higher than 15 and lower than 25 wt%.