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时效对FGH2907合金组织和性能的影响

Influence of Aging Treatment on Microstructural Evolution and Mechanical Properties of FGH2907

  • 摘要: 粉末冶金近净成形工艺制备高温合金环形件是未来航空发动机关键部件制造的重要发展方向。本文以粉末冶金工艺制备的FGH2907合金为研究对象,采用785 ℃不同时效时间处理,研究显微组织演变与力学性能变化规律。结果表明,随着时效时间延长,抗拉强度先升高后降低,塑性持续下降至2 h时的最低值。1 h时效时,γ′相均匀弥散分布且?相极少,强度与塑性匹配最佳;2 h时效后,大量针状?相在晶界及晶内析出,显著提高强度但使塑性急剧下降;4 h时效时,?相粗化聚集,沉淀强化作用减弱,强度降低,塑性略有恢复。本研究为粉末冶金工艺制备FGH2907环形件的热处理制度优化提供了实验依据与理论参考。

     

    Abstract: Near-net-shape forming of alloy rings is regarded as a promising approach for manufacturing critical components in aero-engines. In this work, FGH2907 is aged at 785 °C for different durations to investigate the evolution of its microstructure and mechanical properties. The results indicate that the tensile strength initially increases and then decreases with increasing aging time, whereas the ductility continuously decreases and reaches a minimum at 2 h. After aging for 1 h, the γ′ phase is finely and uniformly distributed in the matrix, while only a small amount of ε phase is present, leading to an optimal balance between strength and ductility. When the aging time increases to 2 h, both the acicular ε phase and the spherical γ′ phase undergo noticeable coarsening, which significantly enhances the strength but results in a marked reduction in ductility. With further aging to 4 h, secondary nucleation of the ε phase and γ′ phase occurs, this weakens the precipitation-strengthening effect, causing a reduction in strength while the ductility shows a slight recovery. These findings provide experimental evidence and theoretical support for optimizing the heat-treatment process of powder-metallurgy FGH2907 alloy rings.

     

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