局部拉弯应力对民机蒙皮2024-T3铝合金剥蚀行为的影响

Impact of Local Tensile and Bending Stress on Exfoliation Corrosion Behavior of Aluminum Alloy 2024-T3 for Civil Aircraft Skin

根据弯梁法自制简易加载装置,结合电化学阻抗谱(EIS)测试方法,研究了民机蒙皮2024-T3铝合金在局部拉弯应力作用下浸泡于剥落腐蚀(EXCO)溶液中的剥蚀行为。结果表明,合金在发生剥蚀时,EIS中将出现2个时间常数。2024-T3铝合金加载试样的EIS在12h时出现2个时间常数,而未加载试样的EIS在12～24h之间才出现2个时间常数,且通过对比剥蚀过程中2种试样EIS的拟合数据,说明局部拉弯应力对2024-T3铝合金剥蚀的发生及发展具有促进作用。

By means of a simple loading device designed for the bending beam test combined with the electrochemical impedance spectroscopy （EIS） testing method, this paper studies the effect of local tensile and bending stress on the exfoliation corrosion （EXCO） behavior of aluminum alloy 2024-T3 for civil aircraft skin immersed in the EXCO solution. The result shows that in the EIS two time constants appeare when the alloy exfoliation corrosion occurres. The EIS of the aluminum alloy 2024-T3 load specimen demonstrate two time constants when immersed in the EXCO solution for 12 h, while the specimen without load demonstrate two time constants between 12 h and 24 h. The comparison of the EIS fitting data of two different specimens during alloy exfoliation corrosion shows that local tensile and bending stress can promote the exfoliation corrosion behavior of aluminum alloy 2024-T3.