Effect of strain textures on the high-temperature interaction of titanium with rarefied gases

Abstract

We studied the influence of the type and degree of perfection of the original crystallographic strain texture of thin-sheet semifinished products of VT1-0 alloy on the processes of high-temperature interaction with rarefied oxygen-containing gases. It is shown that the basic\((0001)[10\bar 10]\) texture facilitates the process of increase in the concentration of interstitial impurities in subsurface layers of the metal, intensifies the process of nucleation of oxide phases, and accelerates the process of formation and growth of oxide films. The\((10\bar 11)[11\bar 20]\) “prismatic” texture is characterized by the intensification of diffusion (gas saturation and sublimation) which manifests itself in an increase in the depth of the zone of solid-solution hardening as well as in the growth of the surface roughness of the metal caused by the development of sublimation micropatterns. The indicated effects become more pronounced as the crystallographic strain texture becomes more perfect. We determine the constants of phase-boundary reactions and estimate the ratios of diffusion coefficients of interstitial impurities for various crystallographic textures. This enables one to take into account the influence of the strain texture on the conditions of mass exchange through the metal-gas boundary as well as the conditions of mass transfer in the titanium matrix and, therefore, to develop a model of the diffusion saturation of titanium alloys in gases.