The effect of nano-Y₂O₃ addition on tensile properties and creep behavior of as-cast TiAl alloy

The effect of nano-Y₂O₃ addition on tensile properties and creep behavior of Ti–45Al–6Nb-2.5V alloy prepared by induction skull melting (ISM) has been studied in this paper. The results reveal that 0.15 at% Y₂O₃ increases both ultimate tensile strength and elongation of the alloy, as 666 MPa and 0.56% at room temperature, 747 MPa and 14.1% at 800 °C, 597 MPa and 22.5% at 900 °C. And the alloy with nano-Y₂O₃ addition displays a better creep resistance and longer creep life at 800 °C. Additionally, the fracture feature shows that the main failure mechanism of TiAl alloy at 800 °C during creep is initiation, growth and coalescence of voids and cracks in grain boundary. Particularly, Y₂O₃ could impede dislocation movement and defer initiation and propagation of cracks to improve creep resistance.