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

摘要

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 degrees C, 597 MPa and 22.5% at 900 degrees C. And the alloy with nano-Y2O3 addition displays a better creep resistance and longer creep life at 800 degrees C. Additionally, the fracture feature shows that the main failure mechanism of TiAl alloy at 800 degrees 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. (C) 2020 Elsevier B.V. All rights reserved.