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本工作研究了２０９０和８０９０合金名义门槛值、本征门槛值和闭合效应对裂纹尾迹的响应关系。Ａｌ－Ｌｉ合金具有优良的疲劳长裂纹门槛值和强的短裂纹效应，其物理本质是高的裂纹闭合效应和裂纹闭合效应的尾迹依赖性．２０９０合金微小裂纹的扩展抗力劣于７０７５合金，系因△Ｋｉ低；８０９０合金的△Ｋｉ与２０２４合金相当，其短裂纹扩展抗力相当或优于２０２４合金，微量稀土元素Ｃｅ可显著改善２０９０合金的本征门槛值，有益于裂纹闭合效应，较大幅度提高其疲劳长、短裂纹扩展抗力。Ｃｅ降低８０９０合金的本征门槛值，有损于其疲劳长、短裂纹扩展抗力。
In this work, the nominal thresholds, intrinsic thresholds and closure effects of 2090 and 8090 alloys on the crack wake response were studied. Al-Li alloy has excellent fatigue crack initiation threshold value and strong short-crack effect, and its physical essence is high crack closure effect and tail-dependence of crack closure effect. The extended resistance of 2090 alloy micro-crack is inferior to that of 7075 alloy due to the low △ Ki. The Δ Ki of 8090 alloy is comparable to that of 2024 alloy, and its short crack propagation resistance is equal to or better than that of 2024 alloy. Trace rare earth element Ce can significantly improve the 2090 alloy The intrinsic threshold value is beneficial to the crack closure effect, greatly improving its fatigue resistance and short crack propagation resistance. Ce reduces the intrinsic threshold of 8090 alloy, detrimental to its fatigue length, short crack propagation resistance.