Metastable phase transformation in quenched VT23 titanium alloy during heating

Phase transformations during heating of hardened VT23 alloy were studied using an x-ray structural camera vacuum attachment. The crystal lattice parameters of β, α'' and α phases were calculated. The stability and temperature of decomposition of metastable phases in VT23 alloy are shown to depend on phase concentration which is determined by prehardening temperature. Redistribution of alloying elements resulting in depleted and enriched areas occurs during decomposition of metastable phases. An α'' phase with high alloying element concentration can decompose within 150-200 deg C according to the mechanism similar to that of reverse martensitic transformation. An α'' phase produced by high temperature hardening is less alloyed, and its decomposition occurs according to the normal diffusion mechanism