高强铝合金在户外海洋大气环境薄液膜腐蚀和弹性应力交互作用下的失效行为与机理研究

As the structural material of the marine equipment superstructure, the corrosion damage behavior of high strength aluminum alloy can be attributed to the interaction of thin electrolyte film corrosion of marine atmospheric environment and elastic stress. Atmospheric corrosion is carried out in a thin electrolyte film, the development of the corrosion process and its secondary effects and the affecting factors are very different from that in the solution. However, the related research that has been carried out at present mainly focus on the electrochemical characterization of loading materials in solution immersion environment. In addition, the synergistic effects between the local corrosion and the local deformation, and the effects of microstructure and corrosion products on the interaction effect, have not yet formed a unified understanding up to now. Based on this, this study intends to use the outdoor actual marine atmosphere as the thin electrolyte film corrosion environment for high strength aluminum alloys, and different elastic stress loads are applied at the same time. It aims to study the corrosion damage law of high strength aluminum alloys under the interaction effect based on surface properties, mechanical properties and electrochemical response characteristics, and to elucidate the effect of stress on the thermodynamics and kinetics of corrosion process. At the same time, the effects of microstructure and corrosion products on the interaction effect are explored, and the failure mechanism is revealed finally. The expected achievement can provides important basic data and theoretical basis for the reliability design of metal structures of marine equipment and the scientific prediction of service life and service safety.

海洋装备上层建筑铝合金结构材料在服役过程中的腐蚀损伤行为是海洋大气环境产生的薄液膜腐蚀和弹性应力交互作用的结果。目前已开展的腐蚀环境和弹性应力交互作用研究主要集中于加载材料在溶液中的电化学行为表征，然而材料在大气环境薄液膜下腐蚀过程的发展及其次生效应等与溶液中差异很大，且两者影响腐蚀的介质因素也有本质不同。此外，对于局部腐蚀与局部形变之间协同作用以及材料组织特征和腐蚀产物膜等对交互作用的影响机制目前还无统一认识。基于此，本课题拟以户外实际海洋大气环境作为高强铝合金的薄液膜腐蚀环境，同时施加不同弹性应力作用，并基于表面性能、力学性能以及薄液膜下电化学响应特性等研究交互作用下的腐蚀损伤规律，阐明应力对腐蚀热力学、动力学过程作用机制，探索微观组织及腐蚀产物膜等对交互作用的影响机制，最终揭示失效机理，为海洋装备金属结构件的可靠性设计以及服役寿命和服役安全的科学预测等提供重要的基础数据和理论依据。

为推进高强铝合金结构材料在海洋装备的工程化应用水平，本项目紧密结合海洋装备上层建筑用高强铝合金在实际服役过程中广泛遭受海洋大气环境薄液膜腐蚀和弹性应力交互作用的服役特点及迫切需求开展了基础研究。项目基于材料腐蚀形貌、力学性能、电化学性能及表面性能等多方面性能演变特征全面获得了高强铝合金在户外海洋大气环境和弹性应力交互作用下的腐蚀损伤规律，分析了不同弹性应力加载条件对交互作用的影响特性。研究表明弹性应力能够加速高强铝合金的腐蚀损伤进程，其中动态应力的加速作用更显著，而静态应力的加速作用随暴露时间的延长不断增强。本项目同时阐明了高强铝合金在户外海洋大气环境和弹性应力交互作用下的腐蚀损伤行为的显著性影响因素及影响机制，揭示了高强铝合金在交互作用下的失效机理。本项目研究可为海洋装备铝合金等金属结构件的可靠性设计以及服役寿命和服役安全的科学预测等提供重要的基础数据和理论依据，对提升海洋装备的环境适应性和服役安全性等具有重要意义。