Influence of nano-Y_2O_3 addition on microstructure and tensile properties of high-Al TiAl alloys

摘要

The effect of nano-Y_2O_3 addition on microstructure and tensile properties of high-Al TiAl alloys prepared by induction skull melting is investigated. The result shows that the addition of nano-Y_2O_3 affords an obvious refinement in lamellar colony due to the heterogeneous nucleation. A crystallographic model is used to predict the α and γ nucleation potencies of Y_2O_3 particles during solidification. Besides, Y_2O_3 induces the solidification pathway of TiAl alloys into high-Al side, resulting in the increase of γ phase. Owing to fine grain strengthening and second phase strengthening, the tensile strength and elongation of TiAl-Y_2O_3 alloys are enhanced significantly at room temperature.