Corrosion behavior of 2195-T8 aluminum-lithium alloy with artificial defects in 30% HNO3
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摘要:
为研究2195-T8铝锂合金在酸性介质中的腐蚀性能,通过扫描电子显微镜(SEM)、扫描透射电子显微镜(STEM)等微观表征手段,分析2195-T8铝锂合金在30% HNO3中的腐蚀形貌。提出一种块分割和边缘检测相结合的图像处理方法,从统计的角度对2195-T8铝锂合金在30% HNO3中的腐蚀规律进行分析。结果表明:合金在浸泡不同时长后出现了典型的点蚀和晶间腐蚀形貌;人工缺陷深度会加剧腐蚀的程度;在腐蚀的初期阶段,蚀坑的数量快速增长,蚀坑面积主要集中在0~20 μm2。而在腐蚀的中后期,蚀坑的数量及面积变化不大,只有少量的蚀坑可以继续扩展形成面积大于50 μm2的蚀坑。
Abstract:To study the corrosion performance of the 2195-T8 Al-Li alloy in an acidic medium, the corrosion morphology of 2195-T8 Al-Li alloy in 30% HNO3 was analyzed by scanning electron microscope (SEM), scanning transmission electron microscopy (STEM) and other microscopic characterization methods. A method for processing images that combines edge detection and block segmentation is also suggested in order to examine the corrosion law of 2195-T8 Al-Li alloy in 30% HNO3 from a statistical perspective. The results show that the typical pitting and intergranular corrosion morphologies of the alloys appear after immersion at different times. The depth of artificial defects can accelerate the progression of corrosion. While the number and area of pits fluctuate little in the middle and later phases of corrosion, only a small number can continue to expand to create etch pits with an area >50 μm2. In the early stages of corrosion, the number of pits increases rapidly, and the pit area is primarily concentrated in 0~20 μm2.
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Key words:
- Al-Li alloy /
- HNO3 /
- artificial defects /
- localized corrosion /
- corrosion laws
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表 1 室温下2195-T8铝锂合金的基本力学性能
Table 1. Basic mechanical properties of 2195-T8 Al-Li alloy at room temperature
材料 抗拉强度σb/MPa 屈服强度σs/MPa 断裂延伸率δ/% 弹性模量E/GPa 2195-T8 609.9 583.3 11.4 72.3 表 2 颗粒的EDS分析结果
Table 2. EDS analysis results of the particles
元素 质量分数 元素 质量分数 Cu 0.0528 Mg 0.0491 Al 0.75 Fe 0.1481 表 3 d = 0.8 mm人工缺陷试样在不同腐蚀时间的点蚀坑数量
Table 3. The number of pitting pits of d = 0.8 mm artificial defect samples at different corrosion times
腐蚀时间/h 点蚀坑数量 A1 A2 A3 A4 6 466 138 22 2 12 814 199 35 9 18 665 196 78 32 -
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