Alloying effect of vanadium on the structure and strength of γ-phase titanium aluminides with aluminum-rich compositions

The effect of vanadium upon the structure and strength of γ-phase titanium aluminide polycrystals containing 55 at.% aluminum has been investigated. The vanadium content was varied from 0 to 20 at.% at 5 at.% intervals. Equiaxed polycrystals were prepared by recrystallizing the hot-deformed materials. The materials containing up to 15 at.% vanadium showed a single phase γ-structure, but the 20 at.% vanadium material contained a small volume fraction of β-phase solid solution based on vanadium. The lattice parameters, a and c, both decreased but the axial ratio, c/a, increased with increasing vanadium content, suggesting that vanadium enhanced the tetragonality of the substitutional solid solution. The 0.2% proof stress increases with increasing vanadium content between room temperature and 1300 K, and appears to be a solid solution strengthening effect.