较系统地研究了低错配度FGH98I和FGH96合金在热处理条件下γ'相的形态演化行为. 结果表明: γ'相的形态失稳形式可归纳为γ'相分裂和γ'相不稳定长出形态, γ'相分裂主要是γ/γ'相间弹性应变场的各向异性和溶质元素富集相互作用造成, 而形状不规则的不稳定长出形态主要是由于基体或晶界局部溶质原子浓度(或过饱和度)变化导致γ'相的非平衡性生长, 讨论了γ'相分裂和不稳定长出形态同时发生现象, 及不连续脱溶析出导致扇形结构的形成机理.
The morphological evolution and its regularity of γ' precipitates in the low mismatch alloys powder metallurgy (P/M) FGH98I and FGH96 under different heat treatment conditions were studied systematically. The results show that the morphological instability of γ' phase can be summarized as the splitting and unstable protrusion. The splitting of γ' phase is caused by the interaction of anisotropic elastic strain field between γ' phase and $\gamma$ matrix which is rich in solute atoms. While the irregular morphology of unstabe protrusion is mainly due to the concentration changes of solute atoms in the matrix or in the local places along grain boundaries, leading to the non-equilibrium growth of γ' phase. The coexist phenomenon of splitting and unstable protrusion, the formation mechanism of fan type structure induced by discontinous precipitation are discussed respectively.
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