大变形2519A铝合金局部腐蚀行为研究
时间:2018-04-22 20:16 来源:毕业论文 作者:毕业论文 点击:次
| 摘要为了探明剧烈变形后时效强化铝合金的抗局部腐蚀的潜力，本论文选择2519A 为研究对象，借助于金相显微镜、扫描电镜等手段，采用 Tafel 实验、浸泡实验法研究了单道次 ECAP 变形再时效后该合金的晶间腐蚀、剥落腐蚀性能。结果表明：经 ECAP 塑性变形的 2519A 铝合金的抗晶间腐蚀性能较固溶态合金高，但抗剥落腐蚀性能低于固溶态合金；变形合金进行 180℃时效处理，随着时效时间的延长，晶间腐蚀深度呈先升后降的趋势，从 85.2μm 上升到 288.0μm 再逐渐下降到 213μm；合金的剥落腐蚀等级虽然变化很小，其严重程度却基本呈先降后升趋势。时效温度的提高，对合金晶间腐蚀影响较小，剥落腐蚀严重程度显著加强。 21603 毕业论文关键词 2519A 铝合金 ECAP 塑性变形 局部腐蚀 时效 Title Study on localized corrosion of severe plastic deformed 2519A aluminum alloy Abstract To explore the localized corrosion potential of age-hardening aluminum alloy subjected to severe plastic deformation, we choose aluminum alloy 2519A as object. By optical microscope and scanning electron microscope the properties of localized corrosion on 2519A aluminum alloy after plastic deformation by ECAP after one-pass and aging were studied by immersion test and Tafel test. The results show that intergranular corrosion depths for samples after one pass ECAPed were sharply decreased compared to samples after solid solution treatment，but exfoliation corrosion resistance shows the opposite tendency. As time gose on, the intergranular corrosion propagation depths was found raised at first, then decreased, form 85.2μ m to 288.0μ m than decrease to 213.5μ m, but diametrically opposite condition was found in the exfoliation corrosion in the 2519A aluminum alloy aged at 180℃. As the aging temperature increases, the influence of intergranular corrosion was decreased, but the exfoliation corrosion just the opposite. Keywords 2519A aluminum ally ECAP localized corrosion aging 目 录 ..I 1 引言 .1 1.1 等通道转角挤压技术概述 .1 1.2 铝合金腐蚀 .3 1.2.1 铝合金晶间腐蚀 4 1.2.1.1 铝合金晶间腐蚀理论 ..4 1.2.1.2 铝合金晶间腐蚀影响因素 5 1.2.2 铝合金剥落腐蚀 6 1.2.2.1 铝合金剥落腐蚀理论 ..6 1.2.2.2 铝合金剥落腐蚀影响因素 6 1.3 本课题研究的意义 8 2 实验 .8 2.1 实验材料 ..8 2.2 实验仪器 ..8 2.3 样品制备及实验方法 9 2.3.1 实验流程 9 2.3.2 样品制备 9 2.3.3 实验方法 10 2.3.3.1 TAFEL 极化曲线测试 .. 10 2.2.3.2 晶间腐蚀 . 10 2.3.3.1 剥落腐蚀 . 10 3 实验结果 .. 10 3.1 Tafel极化曲线 11 3.2 晶间腐蚀 .. 11 3.3 剥落腐蚀 .. 13 4 . 18 4.1 ECAP大塑性变形对铝合金腐蚀性能的影响 .. 18 4.2. 热处理制度对铝合金腐蚀性能的影响 19 结 论 22 致 谢 23 参 考 文 献 .. 24 1 引言 随着科学技术的飞速发展，航空航天技术、军事工业和交通运输领域对制造材料 (责任编辑：qin) |