Fine scale alpha precipitation in Ti-19at.%v in the absence of influence from omega precipitates

Abstract While the isothermal omega-assisted mechanism of homogeneously distributed fine scale alpha precipitation has been well-documented in several titanium alloys, including Ti-19at%V (Ti-20wt%V), this paper reports that a similar type of alpha precipitation may occur in the absence of any direct or indirect influence of omega precipitates. Rapid heating of a beta solution-treated and quenched Ti-19at.%V alloy to 500 °C results in destabilization of the congruent athermal omega precipitates, followed by the development of compositional fluctuations in the form of Ti-rich or V-depleted pockets during isothermal holding, as revealed by atom probe tomography. These pockets possibly result from beta phase separation and may subsequently act as homogeneously distributed alpha nucleation sites.