Microstructural evolution and creep deformation behavior of novel Ti-22Al-25Nb-1Mo-1V-1Zr-0.2Si (at.%) orthorhombic alloy
(1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China;
2. Western Superconducting Technologies Co., Ltd., Shaanxi Province Engineering Laboratory for Aerial Material, Xi’an 710018, China)
2. Western Superconducting Technologies Co., Ltd., Shaanxi Province Engineering Laboratory for Aerial Material, Xi’an 710018, China)
Abstract: 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 α2, 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.
Key words: Ti2AlNb-based alloy; microstructure evolution; heat treatment; creep deformation behavior