Effect of molybdenum content on phase transformations during continuous heating of metastable β Ti-Mo alloys

Abstract

Three metastable $\beta$ titanium alloys with different molybdenum contents, Ti-12Mo, Ti-15Mo and Ti-18Mo (wt.%), were investigated to determine the influence of $\beta$-phase stability on phase transformations during continuous heating. Electrical resistance measurement, dilatometry and differential scanning calorimetry were performed during linear heating at 5 °C/min up to 750 °C. The in-situ experiments were complemented by electron microscopy observations of specimens heated to selected temperatures and subsequently water-quenched. All alloys exhibited a sequence involving partial dissolution of athermal $\omega$ phase, stabilization and growth of isothermal $\omega$ phase, subsequent $\omega$ dissolution and precipitation of $\alpha$ phase. Increasing molybdenum content progressively suppressed $\omega$ phase evolution and subsequent $\alpha$ precipitation and narrowed the temperature interval associated with $\omega$-related transformations. The excellent agreement between electrical resistance measurements, DSC, dilatometry and electron microscopy enabled a consistent description of phase evolution during heating and demonstrated the benefits of combining complementary experimental techniques for investigation of complex transformation pathways in metastable $\beta$ titanium alloys.

arXiv comment21 pages, 10 figures, submitted to Journal of Alloys and Compounds