硫酸阳极氧化对7A65航空铝合金疲劳性能的影响  

Effect of sulfuric acid anodization on fatigue property of 7A65 aluminum alloy for aviation

作　　者：吕弛 张锰 岳珊 陈素明 LYU Chi;ZHANG Meng;YUE Shan;CHEN Suming(AVIC Xi’an Aircraft Industry Group Company Ltd.,Xi’an 710089,China)

机构地区：[1]中航西安飞机工业集团股份有限公司,陕西西安710089

出　　处：《电镀与涂饰》2024年第2期18-26,共9页Electroplating & Finishing

摘　　要：[目的]铝合金零件的疲劳性能是决定飞机服役寿命的关键因素。硫酸阳极氧化是铝合金零件常用的表面处理工艺,研究其对铝合金疲劳性能的影响对指导生产极其重要。[方法]针对新型航空铝合金7A65,采用重复退膜-阳极氧化的方式开展实验。通过疲劳试验机对试样进行疲劳性能测试,绘制应力-疲劳寿命曲线,分析和对比重复退膜和阳极氧化不同次数后7A65铝合金的疲劳性能。通过体视显微镜和扫描电子显微镜对典型断口形貌进行分析,并探讨了其疲劳失效机制。[结果]7A65铝合金在重复退膜-阳极氧化处理后疲劳极限明显下降。经过2次阳极氧化,7A65铝合金的疲劳极限下降为原疲劳极限的61.1%;继续进行退膜-阳极氧化处理,疲劳极限下降趋缓,4次阳极氧化后的疲劳极限为原疲劳极限的56.5%。在此过程中,其疲劳断口呈现出由单一裂纹源向多裂纹源,以及从韧性断裂向脆性断裂的转变。[结论]硫酸阳极氧化对7A65铝合金疲劳性能的影响较大,在生产中应当控制阳极氧化零件的返修次数。[Introduction]The fatigue performance of aluminum alloy part is one of the key factors determining the service life of aircraft.Sulfuric acid anodization is a common surface treatment technology used in manufacturing of aluminum alloy parts.It’s very important to study the effect of anodization on the fatigue performance of aluminum alloys for guiding industrial production.[Method]The anodization and oxide film stripping were conducted repeatedly on a novel aluminum alloy 7A65 for aviation.The fatigue properties of the specimens after the repeated treatment for different times were tested with a fatigue testing machine,and then the strain vs.fatigue life curves were plotted for analysis and comparison.The morphologies of typical fractures were characterized by using stereomicroscope and scanning electron microscope,and the mechanism of fatigue failure was discussed.[Result]The fatigue limit of 7A65 aluminum alloy was greatly decreased after repeated anodization and oxide film stripping.The fatigue limit was decreased to 61.1%of the un-anodized 7A65 aluminum alloy after anodization for twice.The decreasing trend of fatigue limit became slower after oxide film striping and anodization one more time,and the fatigue limit was decreased to 56.5%of the un-anodized 7A65 aluminum alloy after anodization for four times.During these repeated treatment process,the fatigue fracture showed a transition from single to multiple in crack sources,and from ductile to brittle in fracture mechanism.[Conclusion]Sulfuric acid anodization has a significant impact on the fatigue performance of 7A65 aluminum alloy.It is necessary to control reworking times of anodized aluminum alloy parts in industrial production.

关 键 词：铝合金 航空 硫酸阳极氧化 疲劳性能 断口形貌 

分 类 号：TQ153.6[化学工程—电化学工业]