Microstructural evolution and creep deformation behavior of novel Ti−22Al−25Nb−1Mo−1V−1Zr−0.2Si (at.%) orthorhombic alloy

The microstructural evolution and creep deformation behavior which were adjusted and controlled by age treatment of a novel Ti−22Al−25Nb−1Mo−1V−1Zr−0.2Si (mole fraction, %) alloy, were investigated. The microstructures were obtained at different heat treatment temperatures and analyzed by SEM and TEM techniques. The creep behavior of the alloy was studied at 650 °C, 150 MPa for 100 h in air. The results showed that the initial microstructure mainly contained lath-like α ₂ , B2, and O phases. The precipitated O phase was sensitive to aging temperature. With the aging temperature increasing, the thickness of the precipitated O phase was also increased, and the length was shortened. The creep resistance of this alloy was relevant to the morphology and volume faction of the lamellar O phase. The increase of lamellar O phase in thickness was the main reason for the improved creep properties.