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研究正交结构Ti-22Al-26Nb-1Zr合金片层组织在长期时效过程中B2相的分解、O相板条的球化等显微组织演变规律。结果表明:合金加热到B2单相区炉冷后可以获得板条组织,在(O+B2)相区700℃时效100 h以内显微组织无明显变化。但在长时时效过程中板条组织发生明显粗化。在700℃长期时效800 h时,B2相极不稳定,会在时效初期短时间内迅速发生分解。随着时效时间的延长,块状和少量板条状O相在晶界和O/BCC相界处析出并以球状形式长大。此外,在时效时间超过100 h后,会有明显的树枝状O相板条组织形成。
The microstructure evolution of B2 phase decomposition and spheroidization of O-phase lath in the orthorhombic Ti-22Al-26Nb-1Zr alloy sheet was investigated. The results show that the microstructure of the slab can be obtained after the alloy is heated to B2 single-phase furnace, and there is no obvious change in microstructure within 700 h after aging at 700 ℃ for (O + B2) phase. However, the laths obviously coarsen during aging. The long-term aging at 700 ℃ for 800 h, the B2 phase is very unstable, will be in a short period of time early decomposition quickly. With the extension of the aging time, massive and a few lamellar O phases precipitate at the grain boundaries and the O / BCC phase boundaries and grow in a spherical form. In addition, the obvious dendritic O-phase lath was formed after aging for more than 100 h.