Mechanical anisotropy of Ti-6AI-4V alloy with α' martensite microstructure

Ti-6A1-4V alloy are widely used for industrial applications because it combines excellent mechanical properties with low density. During hot-or cold working of Ti-6A1-4V alloy, the grains develop preferred orientations or texture accompanied by the deformation. recrystalligation, grain growth or phase transformation. Such the texture formation results in pronounced anisotropy in mechanical properties. The microstructure consisting of α' martensite phase is expected to reduce the mechanical anisotropy in products of sheet and bar.due to the formation of relatively random crystallographic orientations in α' as compared to equilibrium (α+β). In this work, the mechanical anisotropy of Ti-6A1-4V alloy with α' martensite microstructure is examined with comparing the mechanical properties of alloy with equilibrium (α+β) microstructure. The Ti-6A1-4V alloy heat treated at 1223 K and quenched into ice-water exhibits the (α+α) duplex microstructure and relatively random crystallographic orientations as compared to that in alloy with equilibrium (α+β) microstructure. The mechanical anisotropics of Young's modulus, strength and e- longation to fracture in Ti-6A1-4V alloy-plate are reduced by the formation of the (α+α) duplex microstructure. This result indicates that for-mation of α' martensite microstructure is effective for reducing the mechanical anisotropy in Ti-6A1-4V alloy-plate.