Ordering and decomposition of the β phase in melt-spun TiAl1 − x Vx alloys

Ordering and decomposition of the β phase in melt-spun and aged TiAl1 − x Vx ribbons were studied using calculated phase equilibria and electron microscopy. The phase transformation paths were dramatically changed by rapid quenching from the melt. In the melt-spun ribbons, γ nucleation in the β/B2 matrix and α → α2 ordering were completely suppressed. The β → B2 ordering temperature TC was modelled. The results support the predicted decrease in TC with substitution of Al with V. The effective β → B2 ordering temperature was lowered by high cooling rates. The formation of the ω phase in the melt-spun ribbons and of ω and α2 phases in the aged ribbons is also discussed.