通过组织形态观察和XRD分析, 研究了热处理对GH4169G合金相组成和分布规律的影响.结果表明, 在实验条件下, 合金的组织结构由γ基体、粒状γ′相、圆盘状γ^〞相和δ相组成, 且各相之间保持共格界面, 其中,直接时效处理ITF-DA-GH4169G合金由少量γ′相、大量γ^〞相和γ基体组成, 而长期时效处理ITF-DA-LTA-GH4169G合金由少量γ^′相、大量γ^〞相和γ相及针状δ相组成. 时效期间,随着合金中Nb原子扩散进入γ′相, 使γ′相(001)面的Nb和Ni原子沿1/2<110>方向迁移, L1₂结构的γ′-Ni₃Al相可转变成DO₂₂结构的γ^〞-Ni₃Nb相. 随时效时间延长, γ^〞相长大,γ^〞相单胞中的平行六面体沿特定晶面发生1/6<112>位移,促使γ^〞相转变成DO_a结构的δ-Ni₃Nb. 其中,γ^〞相中的a, b轴与γ基体和γ^′相保持共格界面,可使其沿c轴生长成为圆盘状形态; 而δ-Ni₃Nb相的{200}_δ晶面与γ基体的{111}_γ晶面保持共格界面, 是促使δ相沿(100)晶面生长成为针状的主要原因.

By means of heat treatment at different regimes, microstructure observation and XRD analysis, an investigation has been made into the influence of heat treatment on the phases constitution and distribution regularity of GH4169G alloy. The results show that under the experimental conditions, microstructure of GH4169G alloy consists of γ matrix, particle-like γ′,disc-like γ^〞and δ phases, and the coherent interfaces are kept between the phases. Thereinto, microstructure of directional aging treatment ITF-DA-GH4169G alloy consists of a few γ′phase, lots of γ^〞 and γ phases, however, long-time aging treatment ITF-DA-LTA-GH4169G consists of a few γ′,lots of γ^〞, γ and needle-like δ phases. As the Nb atom diffuses into the lattice of γ′  phase during the aging treatment,γ^′ -Ni₃Al phase with L1₂ structure is transformed intoγ^〞-Ni₃Nb phase with DO₂₂ structure when the Nb and Ni atoms on (001) plane of γ′ phase migrate along 1/2<110> direction. With the growth of γ^〞 phase during the long term aging, the given crystal plane in the new parallelepiped migrates along the 1/6<112> direction, which makes the γ^〞 phase transform into δ-Ni₃Nb phase with DO_a structure. Moreover, the γ^〞 phase may grow up into the disc-like configuration along the c-axis direction due to the restriction of the a- and b-axis coherent interfaces. And it is a main reason that the δ-Ni₃Nb phase grows into needle-like configuration along the (100) plane due to the {200}_δ plane ofδ phase keeps coherent interface with {111}_γ plane of γ matrix phase.