Microstructure and mechanical properties of a new Ti2AlNbbased alloy after aging treatment

A new TiAlNb-based alloy with the composition of Ti-22Al-25Nb-1Mo-1V-1Zr-0.2Si(at%) was fabricated in the sequence of arc melting, forging, solid solution and aging. Present paper focuses on the effects of aging temperatures(700, 750, 800, 850 and 900 ℃) on microstructure, room-temperature tensile properties as well as tensile properties at 650 ℃ and creep properties at650 ℃/150 MPa. It is obvious that the aging treatment promotes the precipitation of O lathes from B2 matrix.With aging temperature increasing, the content of O phase decreases and its size increases gradually, which leads to the decrease in tensile strengths both at room temperature and 650 ℃ and a little increase in ductility. For creep properties, the sample aged at 700 ℃ shows the best creep resistance due to its extremely high O phase content. Aging at 800 ℃ leads to the decrease in the content of O phase and softening of the alloy significantly. However, with aging temperature further increasing from 800 to 900 ℃,the precipitated O phase will be coarsened gradually, which strengthens the alloy again.

A new Ti_2AlNb-based alloy with the composition of Ti-22Al-25Nb-1Mo-1V-1Zr-0.2Si(at%) was fabricated in the sequence of arc melting, forging, solid solution and aging. Present paper focuses on the effects of aging temperatures(700, 750, 800, 850 and 900 ℃) on microstructure, room-temperature tensile properties as well as tensile properties at 650 ℃ and creep properties at650 ℃/150 MPa. It is obvious that the aging treatment promotes the precipitation of O lathes from B2 matrix.With aging temperature increasing, the content of O phase decreases and its size increases gradually, which leads to the decrease in tensile strengths both at room temperature and 650 ℃ and a little increase in ductility. For creep properties, the sample aged at 700 ℃ shows the best creep resistance due to its extremely high O phase content. Aging at 800 ℃ leads to the decrease in the content of O phase and softening of the alloy significantly. However, with aging temperature further increasing from 800 to 900 ℃,the precipitated O phase will be coarsened gradually, which strengthens the alloy again.