前处理工艺对航空铝锂合金硫酸阳极氧化膜层性能影响

针对一种新研制的航空用Al-Li-Cu-Zn-Mg系铝锂合金,采用了光学显微镜、电子显微镜和能谱分析技术,分析碱腐蚀和三酸脱氧两种不同前处理工艺对铝锂合金硫酸阳极氧化膜层的外观、耐蚀性和疲劳性能的影响规律。结果表明:相比三酸脱氧工艺,碱腐蚀工艺对铝锂合金表面的腐蚀程度较深,晶界处的耐腐蚀能力较差,硫酸阳极氧化膜层表面形成了网状晶界形貌;采用碱腐蚀处理的试样疲劳寿命较三酸脱氧处理试样更低,而不同前处理后经过硫酸阳极氧化的试样疲劳寿命相差不大。不同前处理对铝锂合金的硫酸阳极氧化膜层的耐蚀性的影响不大。

Effect of Pretreatment Process on Properties of Aerospace Al-Li Alloy Sulfuric Acid Anodic Film

Aiming at a new Al-Li alloy,by the use of optical microscope,SEMand EDS,we analyzed the effects of different pretreat-ment processes including alkali corrosion and tri-acid deoxidation on the appearance,corrosion resistance and fatigue properties of sul-furic acid anodic oxide coatings.which provided a theoretical basis for the design,selection,application and surface protection of Al-Li alloy structural components.We found that the corrosion degree of the Al-Li alloy surface by alkali corrosion was deeper than that of the tri-acid deoxidation process.The corrosion resistance at the grain boundary was poor,so the mesh surface morphology of the anodic oxide film was formed.The fatigue life of the samples treated with alkali corrosion was lower than that of the tr-ioxic acid treatment,the fatigue life of the samples subjected to sulfuric acid anodic oxidation is different.The effect of different pretreatment on the corrosion re-sistance of the sulfuric acid anodic oxide layer of Al-Li alloy is not significant.