High temperature tensile properties and fracture behavior of Y₂O₃-bearing Ti-48Al-2Cr-2Nb alloy

In present work, the effect of Y₂O₃ on tensile properties and fracture behavior of Ti-48Al-2Cr-2Nb alloy at elevated temperature was investigated. The alloys were successively fabricated by induction skull melting. The results revealed that tensile strength and elongation of the Y₂O₃-bearing TiAl alloy both improved evidently at elevated temperature. The TiAl-Y₂O₃ alloy still exhibited considerable mechanical properties with ultimate tensile strength of 587 MPa and elongation of 23.0% at 850 °C. Simultaneously, the brittle-ductile transition temperature of the TiAl-Y₂O₃ alloy reduced about 50 °C, which displayed the toughness fracture feature with dimples firstly at 800 °C. In addition, Y₂O₃ could effectively prevent the movement of dislocation and promote the nucleation of deformation twins during tensile testing. The excellent properties could be attributed to the compounding effect of fine lamellar phase, increasing content of γ phase and dispersive Y₂O₃ particles.