Microstructure and superplasticity of a Ti-25Al-10Nb-3V-1Mo intermetallic alloy

Superplastic properties in tension of a Ti-25Al-10Nb-3V-1Mo (at.%) alloy were studied in the temperature range 850–1050 °C under inert gas. The as-received material exhibits a fine elongated duplex structure with a significant rolling texture. Optimum superplastic properties are obtained for temperatures in the interval 930 ⩽ T ⩽ 980 °C. At T = 930 °C, an equiaxed structure is produced in the first steps of deformation, and dynamic phase growth remains limited. A decrease in the initial texture is associated with the superplastic deformation. The values of the apparent activation energy in the superplastic regime were determined. The respective contributions of solute effects and phase volume fractions to the experimentally obtained activation energies are discussed.