航空学报 > 2025, Vol. 46 Issue (21): 532364-532364   doi: 10.7527/S1000-6893.2025.32364

中国飞机强度研究所建所 60 周年专刊

高温条件下FGH4108合金的保载-疲劳裂纹扩展行为

秦豪1, 刘强1(), 江荣2, 宋迎东2, 张强3, 刘建涛3, 邓健1, 卢天健1   

  1. 1.南京航空航天大学 多功能轻量化材料与结构工信部重点实验室,南京 210016
    2.南京航空航天大学 航空发动机热环境与热结构工信部重点实验室,南京 210016
    3.钢铁研究总院 高温材料研究所,北京 100081
  • 收稿日期:2025-06-03 修回日期:2025-06-17 接受日期:2025-07-07 出版日期:2025-07-28 发布日期:2025-07-15
  • 通讯作者: 刘强 E-mail:liuqiang2015@nuaa.edu.cn
  • 基金资助:
    国家自然科学基金(12272174);国家科技重大专项(2017-Ⅵ-0008-0078);江苏省双创团队(JSSCTD202206);江苏省自然科学基金(BK20220136);航空发动机及燃气轮机基础科学中心重点项目(P2022-B-Ⅲ-007-001)

Dwell-fatigue crack growth behavior of FGH4108 alloy at high temperature

Hao QIN1, Qiang LIU1(), Rong JIANG2, Yingdong SONG2, Qiang ZHANG3, Jiantao LIU3, Jian DENG1, Tianjian LU1   

  1. 1.MIIT Key Laboratory of Multifunctional Lightweight Materials and Structures,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China
    2.MIIT Key Laboratory of Aero-engine Thermal Environment and Structure,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China
    3.High Temperature Material Institute,Central Iron and Steel Research Institute,Beijing 100081,China
  • Received:2025-06-03 Revised:2025-06-17 Accepted:2025-07-07 Online:2025-07-28 Published:2025-07-15
  • Contact: Qiang LIU E-mail:liuqiang2015@nuaa.edu.cn
  • Supported by:
    National Natural Science Foundation of China(12272174);Innovation and Entrepreneurship Teams of Jiangsu Province(JSSCTD202206);Natural Science Foundation of Jiangsu Province(BK20220136);National Science and Technology Major Project (2017-Ⅵ-0008-0078);Key Project of the Basic Science Center for Aero Engines and Gas Turbines (P2022-B-Ⅲ-007-001)

摘要:

针对第4代粉末高温合金FGH4108,开展不同温度、不同保载时间下的疲劳裂纹扩展实验和中断实验研究,并结合扫描电子显微镜(SEM)、电子背散射衍射(EBSD)、电子探针X射线显微分析(EPMA)等表征手段分析温度和保载时间对裂纹扩展行为的影响,揭示氧化损伤对裂纹扩展的影响机理,提出1种描述机械-氧化耦合作用的疲劳裂纹扩展速率模型。结果表明:随着温度和保载时间增加,裂纹扩展速率上升,疲劳寿命显著下降;断面特征分析发现,在650 ℃时疲劳裂纹主要呈现穿晶扩展、断面平整,在750 ℃以上时疲劳裂纹主要呈现沿晶扩展、并伴随着二次裂纹的形成;同时,裂纹扩展过程中还伴随有尖端形貌改变与氧化物生成等现象,揭示了氧化作用对裂纹扩展的影响。提出的模型可以较好地描述不同温度与保载时间下的疲劳裂纹扩展速率,同时解耦了机械损伤、氧化损伤对裂纹扩展的影响,并确定了氧化损伤参数的温度相关性。

关键词: 粉末高温合金, 氧化损伤, 疲劳裂纹扩展, 裂纹扩展速率模型, 高温

Abstract:

Fatigue crack growth experiments and interrupted tests are conducted on the fourth-generation powder metallurgy superalloy FGH4108 under varying temperatures and dwell time. The influence of temperature and dwell time on crack growth behavior is analyzed using characterization techniques such as Scanning Electron Microscopy (SEM), Electron Backscatter Diffraction (EBSD), and Electron Probe Microanalysis (EPMA). The mechanism by which oxidation damage affects crack growth is revealed. A fatigue crack growth rate model describing the mechanical-oxidation coupling effect is proposed. The results show that as temperature and dwell time increase, the crack growth rate rises and fatigue life decreases significantly. Fractographic analysis reveals that at 650 ℃, fatigue cracks primarily propagate transgranularly with relatively flat fracture surfaces, while at temperatures above 750 ℃, fatigue cracks mainly propagate intergranularly, accompanied by the formation of secondary cracks. Concurrently, phenomena such as alterations in crack tip morphology and oxide formation were observed during crack propagation, elucidating the impact of oxidation on crack growth. The proposed model can better describe the fatigue crack growth rate at different temperatures and dwell time. At the same time, the effects of mechanical damage and oxidative damage on crack growth are decoupled, and the temperature dependence of oxidative damage parameters is determined.

Key words: powder metallurgy superalloy, oxidation damage, fatigue crack propagation, crack propagation rate model, high temperature

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