不同表面状态2024-T3铝合金腐蚀行为及DFR退化规律

目的研究阳极氧化膜破损的航空铝合金试件在实验室加速腐蚀条件下的腐蚀行为和疲劳性能退化规律,并和阳极氧化膜完好的试件进行对比。方法以不同表面状态的2024-T3铝合金试件为研究对象,进行不同时长的实验室加速腐蚀试验和与加速腐蚀后的DFR试验。通过观察腐蚀形貌,测量腐蚀坑深度和孔蚀率来观测腐蚀行为,通过计算腐蚀后的DFR来研究DFR退化规律。结果阳极氧化膜完好、破损的2024-T3铝合金试件分别在加速腐蚀180、36 h后出现点蚀坑,平均点蚀坑深度与加速腐蚀时间符合幂函数关系。试件在实验室加速腐蚀条件下,DFR的退化规律符合指数函数关系。结论与阳极氧化膜完好试件相比,阳极氧化膜破损会导致2024-T3铝合金试件的耐腐蚀性降低,加速试件疲劳性能退化的速率。

Corrosion Behavior and DFR Degradation Law of 2024-T3 Aluminium Alloy in Different Surface State

The paper aims to study the corrosion behavior and fatigue deterioration law of aeronautical aluminium alloy specimens with damaged anodic oxide film under accelerated corrosion conditions in laboratory, and to compare with specimens with intact anodic oxide film.2024-T3 aluminium alloy specimens with different surface states were studied, accelerated corrosion tests of different time lengths and DFR experiments after accelerated corrosion were carried out. Corrosion behavior was observed by observing corrosion morphology, measuring pit depth and pitting corrosion rate. Degradation law of DFR was studied by calculating the DFR after corrosion. Corrosion pits appeared in 2024-T3 aluminium alloy specimens with intact and damaged anodic oxide film after 180 h and 36 of accelerated corrosion, respectively. The average corrosion pit depth and accelerated corrosion time coincided with power function relations. The degradation laws of DFR of the specimen with intact anodic oxide film and damaged anodic oxide film under accelerated corrosion in laboratory coincided with exponential function. Compared with the specimens with intact anodic oxide film, the damage of anodic oxide film would reduce the corrosion resistance of 2024-T3 aluminium alloy specimens and accelerate the degradation rate of fatigue property of specimens.