时效时间对 FGH2907 合金组织和性能的影响

Influence of aging time on microstructural evolution and mechanical properties of FGH2907 alloys

摘要

以等离子旋转电极法制备 FGH2907 合金粉末为原料，采用热等静压工艺制备 FGH2907 合金试样。将试样进行固溶时效热处理，时效时间分别为 1 h、2 h 和 4 h，研究不同时效时间对 FGH2907 合金显微组织演变与力学性能变化的影响。结果表明，随着时效时间延长，FGH2907 合金的抗拉强度先升高后降低，塑性先下降后略有回升。经过 1 h 时效处理，合金中 γ′相均匀弥散分布且 ε 相较少，强度与塑性匹配最佳；经过 2 h 时效处理，针状ɛ相和球状 γ′相发生粗化，显著提高强度但塑性急剧下降；经过 4 h 时效处理，ε 相和 γ′相二次形核，沉淀强化作用减弱，强度降低，塑性略有恢复。

Abstract

The near-net-shape forming of alloy rings is regarded as the promising approach for manufacturing critical components in aero-engines. The FGH2907 alloy powders were prepared by plasma rotating electrode process, and the FGH2907 alloys were fabricated by hot isostatic pressing. The specimens were subjected to solution and aging heat treatments for 1 h, 2 h, and 4 h, respectively. The effects of aging time on microstructural evolution and mechanical properties of the FGH2907 alloys were investigated. Results show that, with the prolonged aging time, the tensile strength initially increases and then decreases, while the ductility first decreases and then slightly recovers. After 1 h of aging, the γ′ phases are uniformly and finely dispersed within the matrix, and the ε phase content is low, resulting in the optimal balance between strength and ductility. After 2 h of aging, the needle-like ε phases and the spherical γ′ phases coarsen significantly, leading to the marked increase in strength but the sharp decline in ductility. After 4 h of aging, the secondary nucleation of the ε phases and γ′ phases occurs, weakening the precipitation hardening, leading to the reduce in strength and the slight recovery in ductility.

关键词

FGH2907 合金 / 时效处理 / 力学性能 / ε 相 / 显微组织

Key words

FGH2907 alloys / aging treatment / mechanical properties / ε phase / microstructure

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