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采用室温拉伸和Kahn撕裂测试方法,对一种加入不同含Ce量的新型Al-Cu-Li合金在T6态和T8态峰时效时的力学性能分别进行了测试;同时辅以扫描电镜和透射电镜对其断口形貌和晶界析出相相应的变化规律进行了研究。对所有状态样品的断口扫描照片和晶界析出相情况进行了统计。结果表明:T8态的强度值和UIE值(unit initiation energy)总体高于T6态,中等含Ce量的合金在T8态具有最高的强韧性配合。断口分析中发现:具有韧窝环绕金属间化合物特征的区域所占面积分数的变化趋势与UIE值变化规律一致;晶界分析表明:无析出带宽度的大小、晶界析出相的数密度和有效尺寸的变化决定了样品在不同Ce含量和热处理状态下的断裂阻力和裂纹扩展方式。
The mechanical properties of a new type of Al-Cu-Li alloy with different content of Ce at the time of aging of T6 and T8 were tested respectively by room temperature tensile test and Kahn tear test. At the same time, Transmission electron microscopy of the fracture morphology and grain boundary precipitation corresponding changes in the law were studied. The statistics of fracture scanning pictures and grain boundary precipitates of all the state samples were calculated. The results show that the T8 state strength and the unit initiation energy are higher than the T6 state, while the medium Ce content alloy has the highest strength and toughness in the T8 state. The analysis of fracture surface shows that the change trend of the area fraction occupied by the region with dimple intercalation intermetallic compounds is consistent with the variation of UIE value. The grain boundary analysis shows that the size of precipitate-free zone, the number density and effective The change of size determines the fracture resistance and crack propagation mode of the sample under different Ce contents and heat treatment conditions.