Study of the irradiation-induced α → ω phase transformation in titanium: Kinetics and mechanism

Abstract

An atomic-crystallographic mechanism is proposed for the α → ω transformation during irradiation. The mechanism is based on the propagation of a localized displacement wave of the [100]α close-packed rows. From the phonon dispersion curves along (010)α, the displacement wave is decomposed into two transverse optical phonons and one transverse acoustic phonon. The proposed mechanism accounts for the ω morphology and can explain the presence of (210)α planes of diffuse intensity in reciprocal space. The kinetic of the transformation was followed by in-situ length and electrical resistance measurements. An analytical model based on the proposed mechanism enabled us to fit the experimental curves. Finally the kinetic results were compared with those obtained previously for the transformation occurring under an applied static pressure.