Ultra-thin twin plates and growth domains in the γ phase as a product of the B2 phase decomposition in Ti–40 at.% Al–10 at.% V

Abstract

Abstract The transformation-induced ultra-thin plates of γ twins in the Ti–40 at.% Al–10 at.% V alloy in which γ is formed from B2 were studied. While such twins are frequently observed in Ti–40 at.% Al–10 at.% V due to the B2→ γ transformation, they have not been observed in γ lamellae of the α2-γ lamellar structure formed via the α and α2 → α2 + γ transformations in γ-TiAl-based alloys or in γ nucleated from β (A2). The results show that these ultra-thin twin plates are secondary twins formed between the growing-in fronts of separately nucleated γ domains. The effect of the ordering in the β phase on the formation of planar defects in γ is also discussed.