基于腐蚀损伤表征参数的铝合金预腐蚀疲劳裂纹扩展修正模型

摘要

Pit corrosion morphology prevails on aluminum alloy surface when subjected to corrosive media in service environment, which will favor crack initiation and accelerates crack propagation behavior, thus it threatens the engineering structure safety. This paper establishes a linear elasticity fatigue crack characterizing with respect to pit corrosion parameter and verify the validity of the proposed model by experimental data from prior-corrosion fatigue test of aluminum alloy. The proposed model is of reference value for corrosion fatigue life and damage tolerance evaluation of aluminum alloy structure.%服役环境中的腐蚀介质会在铝合金表面形成以腐蚀坑为代表的典型点蚀形貌。在疲劳载荷作用下，这些腐蚀坑会有助于裂纹的萌生，加速并影响其扩展行为，威胁结构安全。考虑腐蚀坑的影响，建立了一个基于腐蚀损伤表征参数的线弹性裂纹扩展表征模型。利用航空结构中常见承力构件所采用的LD2铝合金进行验证性实验。结果表明，所建立的模型能够反映出腐蚀损伤对于裂纹扩展行为的影响，对于铝合金构件的腐蚀疲劳寿命预测和损伤容限评估具有参考价值。