典型服役环境中各向异性高强AZ80镁合金的电偶腐蚀机理与失效机制研究

项目名称： 典型服役环境中各向异性高强AZ80镁合金的电偶腐蚀机理与失效机制研究

项目编号： No.51501181

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 蒋全通

作者单位： 中国科学院海洋研究所

项目金额： 20万元

中文摘要： 装备于航空航天的高强AZ80镁合金，通过与铍青铜紧固件偶联，共同构成整体服役。在实际应用过程中，合金极易发生电偶腐蚀。由于变形镁合金织构的存在，其耐腐蚀性能存在各向异性，沿ED(挤压方向)、TD(横向)、ND(法向)腐蚀的萌生点、裂纹扩展方式和耐腐蚀寿命不同。前期预研中，我们测试了典型服役环境中ED方向“AZ80镁合金/铍青铜”的腐蚀失重速率。然而，关于晶体学各向异性对电偶腐蚀的影响规律和作用机理，腐蚀裂纹的萌生及扩展方式，合金断裂失效机制和耐腐蚀寿命等均需进一步研究。本项目拟采用长周期大气暴露试验和电化学腐蚀等手段，分析不同取向的电偶腐蚀速率、力学强度变化规律、腐蚀裂纹萌生与扩展方式及机理；阐述织构、环境因素、服役周期等的协同效应；基于FMEA理论，揭示合金的失效机制，建立腐蚀模型，科学预测合金的服役寿命。通过研究有效推进高强AZ80镁合金在航空航天和国防军工等领域的应用。

中文关键词： AZ80镁合金；各向异性；电偶腐蚀；失效机理

英文摘要： High-strength AZ80 magnesium alloys coupled with QBe1.7 beryllium bronze fasteners together were equipped to service in aerospace field. In the process of application, galvanic corrosion easily occurred. The corrosion behaviors AZ80 magnesium alloys existed anisotropy due to the textures, resulting the location of crack initiation and growth along the ED (extrusion direction), TD (transverse direction), ND (normal direction) were different. In the preliminary works, we tested “AZ80 magnesium alloy/beryllium bronze” galvanic corrosion weight loss rates along the extrusion direction in the typical service environment. However, the crystallographic anisotropy on the regularity and mechanism of the influence of galvanic corrosion, corrosion crack initiation and propagation mode, failure mechanism and service life needs to be studied further. This project intends to adopt the long cycle of atmospheric exposure tests and electrochemical corrosion, analysis the different orientation of AZ80 alloys galvanic corrosion rates, mechanical strength, crack initiation, propagation mode and mechanisms. The synergistic effect of the crystallographic orientation, service cycles and environments on the corrosion behavior will be expounded. Based on the theory of failure mode and effect analysis, the project will reveal the failure mechanism and corrosion model for different orientation galvanic. Then the service life alloy in service environment will be forecasted reasonably. This project will promote the applications for high-strength AZ80 magnesium alloy in the aerospace and national defense fields.

英文关键词： AZ80 magnesium alloy;anisotropy;galvanic corrosion;failure mechanisms