通过带加温系统的扫描电镜原位观测技术研究了胶接修补固化温度对LY12CZ铝合金疲劳裂纹扩展行为的影响。结果表明: 高温使得LY12CZ铝合金中萌生孔洞并聚集长大, 从而易于萌生短裂纹, 产生沿晶破裂趋势, 降低材料的疲劳性能; LY12CZ铝合金疲劳裂纹扩展门槛值随着温度的升高逐步降低, 且在温度撤除后, 疲劳裂纹扩展门槛值并未恢复到常温状态下的门槛值, 因此胶接修补过程中需要严格控制胶黏剂的固化温度, 以减小其对基体材料疲劳性能的影响。

The effects of elevated curing temperature on fatigue cracking propagation behavior of LY12CZ aluminum alloy during bonded repair process were studied by scanning electronic microscope (SEM) which could provide heating system in-situ observation technique. The results indicate that the elevated temperature would promote initiation and coalescence of inner hole, then accelerate initiation of small cracks and inclination of intergranular fracture, and finally decrease the fatigue resistance ability. The fatigue crack propagation threshold value of LY12CZ aluminum alloy decreased with the increase of the elevated temperature. What’s more, the fatigue crack propagation threshold value could not regain its value at room temperature with the elevated temperature removing. So the elevated curing temperature must be as low as possible to minimize the effect of temperature on fatigue resistance property of the matrix aluminum alloy.