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本文对1420Al－Li合金厚板采用紧凑拉伸、三点弯曲、电镜原位拉伸疲劳等方法，考察了不同取向的疲劳裂纹扩展行为，观测了长裂纹扩展路径形态、讨论了层状结构与材料疲劳性能之间的关系结果表明，层片的界面对板材的疲劳性能具有重要影响，在裂纹扩展过程中，层片与裂纹尖端相互作用，通过不同的外韧化作用使得1420合金裂纹扩展的阻力在不同取向出现显著差异．在L－T和T－S取向时，在△K为3－4和6－gMPa·m1／2范围内出现了裂纹扩展的“自抑制”现象
In this paper, the fatigue crack growth behavior of 1420Al-Li alloy plate with compact orientation, three-point bending and in-situ tensile fatigue under electron microscope was investigated. The morphology of long crack growth path was observed. The effects of layered structure and The relationship between the fatigue properties of the materials shows that the interfacial layer has an important influence on the fatigue properties of the sheet. During the crack propagation, the lamellae interact with the crack tip to make the 1420 alloy crack propagate through different external toughening Resistance in different orientations significant differences. In the L-T and T-S orientations, a “self-suppressing” phenomenon of crack propagation occurred in the range of ΔK of 3-4 and 6-gMPa · m1 / 2