Formation conditions of omega phase in the titanium alloys after quenching

Abstract

Features of athermal omega phase of anomalous morphology, as massive precipitations of "rafting" structure, in the Ti-Nb, Ti-V systems have been studied. It is shown that necessary conditions of "rafting" orphase formation are, firstly, competition of β → α ″ - and β → ω- transformation in process of quenching below temperature T=Tω = Ms, secondly, the value of electron concentration of ß-solid solution (e/a) corresponding to the lower limit of critical values of e/a, where the formation of omega phase is possible. A dislocation model,which explains morphology features of "rafting" orphase, was suggested. The formation of "rafting" ω-phase in the structure of quenching titanium alloys was found to promote increasing of physical-mechanical characteristics.