夹层结构自冲铆接头的腐蚀行为及力学性能

Corrosion behavior and mechanical properties of sandwich structure self-piercing riveted joint

通过盐溶液周期浸润腐蚀试验,研究以AA5052铝合金为基板的泡沫铁镍夹层结构自冲铆接头的耐腐蚀性能,并用扫描电镜观察接头的腐蚀产物,再对各腐蚀时间的接头进行拉伸-剪切试验,探究夹层结构自冲铆接头的腐蚀行为,并揭示腐蚀对接头力学性能的影响。此外,总结了周浸腐蚀对接头能量吸收能力的影响规律。结果表明:不同腐蚀时间接头的拉伸失效模式变化的原因与其内部的腐蚀行为相关;接头的残余抗剪强度随周浸腐蚀时间的增加呈先增加后递减的趋势,失效位移和能量吸收值在周浸腐蚀前30 d先减小再增加,而30 d以后逐渐减小,这主要是受接头内部界面上腐蚀产物形貌演变的影响。

The corrosion resistance of SPR joint with AA5052 aluminum alloy as substrate and foam iron-nickel as inter-layers was studied by carrying out salt solution periodic immersion corrosion tests. The corrosion products of the joints were observed by SEM,and then the tensile-shear tests were carried out on the joints corroded for different corrosion time. The corrosion behavior of sandwich structure SPR joint was investigated,and the influence of corrosion on the mechanical performance of the joint was revealed. Furthermore,the influence law of the periodic immersion corrosion on the energy absorption capacity of the joint was summarized. The results indicate that the reason for the change of tensile failure mode of joints with different corrosion time is related to their internal corrosion behavior. The residual shear strength of the joint increases first and then eventually decreases with the increase of periodic immersion corrosion time. The failure displacement and energy absorption value of the joint decrease first and then increase in the first 30 days of the test,and decrease gradually after 30 days,which are mainly affected by the morphology evolution of corrosion products at the inner interface of the joint.