Effects of Mo on the solidification structure and solidification route of high Nb-TiAl alloy prepared by a non-consumable arc melting furnace in an argon atmosphere were analyzed.The results reveal that solidification route is changed and solidification structure is refined in Ti-46Al-6Nb-0.2B alloy with Mo addition.With 1% Mo addition

solidification structure of the alloy is composed of α2 phase and γ phase as well as minor β phase

and major β phase is segregated along the grain boundary as network structure

and the minor one is distributed in lamellar colony as strip structure.With increasing in Mo addition

β phase is increased.Based on phase diagram

solidification route of the high Nb-TiAl alloy with different Mo content was presented.