EFFECTS OF MICROSTRUCTURE ON HIGH-CYCLE FATIGUE OF AN AL-ZN-MG-CU ALLOY (AL-7055)
EFFECTS OF MICROSTRUCTURE ON HIGH-CYCLE FATIGUE OF AN AL-ZN-MG-CU ALLOY (AL-7055)
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发表时间：
2003-05
影响因子：
5.4
通讯作者：
L. E. Oswald
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文献类型：
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作者：
L. E. Oswald
微观组织对铝-锌-镁-铜合金（AL-7055）高周疲劳性能的影响林恩尤金奥斯瓦尔德，匹兹堡大学，2003年。虽然在各种研究中已经报道了疲劳开始的拟议过程和机制，但仍然存在需要改进理解的领域。目前的研究探讨了微观结构特征在疲劳裂纹萌生方面所起的作用。7055合金已被商用飞机制造商广泛接受用于机翼上蒙皮。该产品显示出压缩屈服强度、断裂韧性和耐腐蚀性的独特组合，这些都是用于以压缩为主的上翼结构所需的。疲劳裂纹萌生被飞机设计师用来确定飞机必须遵守的初始检查间隔。通过增加铝合金的抗疲劳起始性，飞机可以在初始检查之前经受额外的飞行。成分颗粒（Mg_2Si和Al_7Cu_2Fe）对7055合金的疲劳裂纹萌生抗力起主要作用。在目前的研究中，Mg 2Si被确定为在抗疲劳裂纹萌生方面的微观结构中的特别有害的特征，与Al 7 Cu 2Fe相比。这些颗粒的弹性和塑性行为，如用配备有纳米压痕仪的原子力显微镜（AFM）测定的，揭示了与含Si颗粒相比，含Fe颗粒更耐断裂并且表现出增加的塑性。
ABSTRACTEFFECTS OF MICROSTRUCTURE ON HIGH-CYCLE FATIGUE OF AN AL-ZN-MG-CU ALLOY (AL-7055)Lynn Eugene Oswald, MSUniversity of Pittsburgh, 2003The study of fatigue in aluminum alloys is an area that has been studied for many years. Although proposed processes and mechanisms for fatigue initiation have been reported in various studies, there still exist areas that require improved understanding. The current study examines the role that microstructural features can play with regard to fatigue crack initiation.Alloy 7055 has found wide acceptance by commercial aircraft manufacturers in the use of upper wing skins. This product displays a unique combination of compressive yield strength, fracture toughness and corrosion resistance which are required for use in compression-dominated upper wing structures. Fatigue crack initiation is used by aircraft designers to determine the initial inspection intervals an aircraft must adhere to. By increasing the fatigue initiation resistance of an aluminum alloy, an aircraft can endure additional flights prior to initial inspection. This has an obvious impact on the financial and safety performance of the structure.Constituent particles (Mg2Si and Al7Cu2Fe) play a primary role in the fatigue crack initiation resistance of 7055 alloy. In the current study Mg2Si was determined to be a particularly damaging feature in the microstructure in terms of fatigue crack initiation resistance, as compared to Al7Cu2Fe. The elastic and plastic behavior of these particles, as determined with an atomic force microscope (AFM) equipped with a nanoindenter, revealed that the Fe-bearing particles were more resistant to fracture and exhibit increased plasticity, as compared to the Si-bearing particle.