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利用三维原子探针(3DAP),SEM,TEM和相分离方法,研究了5种Hf含量的FGH97粉末冶金高温合金中Hf在γ基体、γ′相和MC相中的分配,以及Hf对γ′和MC析出相的数量、组成和形貌的影响.结果表明:Hf主要进入γ′相和MC型碳化物,γ′相变为(Ni,Co)_3(Al,Ti,Nb,Hf),MC碳化物变为(Nb,Ti,Hf)C.随着合金中Hf含量的增加,Hf进入γ′相的比例基本不变,进入MC相的比例逐渐增大,进入γ相的比例逐渐减小,即Hf在γ′和MC相的分配比R_1逐渐减小,在γ′和γ相的分配比R_2逐渐增大,R_1和R_2的平均值分别为1:0.1和1:0.05,这表明Hf主要分配在γ′相中,其次分配在MC相中.Hf促进γ′相和MC相析出,影响γ′相的尺寸和形貌,对MC碳化物的尺寸和形貌的影响并不明显.
The distribution of Hf in γ matrix, γ ’phase and MC phase in FGH97 powder metallurgy superalloy with five Hf contents was studied by three-dimensional atom probe (3DAP), SEM, TEM and phase separation method. The effects of Hf on γ’ (Ni, Co) _3 (Al, Ti, Nb, Hf), and the phase transition of γ ’phase to (Ni, Co) MC carbides become (Nb, Ti, Hf) C. With the increase of Hf content in the alloy, the proportion of Hf entering the γ ’phase is basically unchanged, the proportion of entering the MC phase is gradually increased, and the proportion of entering the γ phase is gradually decreased That is, the distribution ratio of Hf in γ ’and MC phase decreases gradually, while the distribution ratio of γ’ and γ phase increases gradually, the average value of R_1 and R_2 is 1: 0.1 and 1: 0.05 respectively Hf is mainly distributed in the γ ’phase and secondly in the MC phase, and Hf promotes the precipitation of γ’ phase and MC phase, affecting the size and morphology of the γ ’phase, and has no obvious effect on the size and morphology of the MC carbide .