研究了含微量元素Hf(0-0.89%)的FGH97粉末高温合金中拓扑密排μ相的析出动力学、组织形态以及μ相对Hf含量为0.30%的合金盘坯力学性能的影响。结果表明：Hf含量为0.30%和0.89%的合金经750-900℃长期时效后μ相已明显析出，并随着时效温度的升高、时效时间的延长以及Hf添加量的增加，μ相析出量增加和尺寸长大。合金中的μ相主要在晶内以长条片状形态析出。合金盘坯(Hf含量为0.30%)在550-650℃长期时效后没出现μ相，高温拉伸性能和高温持久性能没有降低，组织稳定性良好。750℃长期时效后μ相的析出对合金盘坯的高温拉伸强度无明显影响，但降低拉伸塑性和高温持久寿命，而提高持久塑性约20%。详细讨论了μ相的析出行为、γ固溶体中合金元素的再分配以及合金断裂断口的特征，从理论上解释了μ相对力学性能的影响的脆-韧双重作用的机理，并提出控制和避免μ相大量析出造成性能劣化的措施和方法。

The precipitation kinetics and morphology of topologically close-packed μ phase in FGH97 powder metallurgy superalloy with 0-0.89 % microelement Hf and the effect of μ phase on the mechanical properties of FGH97 powder metallurgy superalloy billet with 0.30 % Hf has been investigated. The results showed that μ phase precipitated obviously in the alloys with 0.30 % and 0.89 % Hf after long-term aging at 750-900℃, the amount and size of μ phase increased as the aging temperature, aging time and Hf content increasing. μ phase mainly precipitated in grains as strip and flake shapes. After long-term aging at 550-650℃, no μ phase precipitated in FGH97 PM superalloy billet with 0.30 % Hf and the tensile properties and stress-rupture properties at high temperature were not decreased, which showed excellent microstructure stability. After long term aging at 750℃, precipitated μ phase had little effect on tensile strength at high temperature, however, the tensile ductility and high temperature stress rupture life reduced, and the stress rupture ductility increased by about 20%. In this paper, the precipitation behavior of μ phase, the redistribution of elements in γ solid solution and the FGH97 PM superalloy fracture morphology characteristics have been discussed in detail. The mechanism of the brittle and ductile dual effect of μ phase on the mechanical properties has been explained theoretically. The methods of controlling and avoiding excessive μ phase precipitation which leaded to performance deterioration have been proposed.