时效制度对挤压Al-6.2Zn-2.3Mg-2.3Cu铝合金电化学腐蚀性能的影响

发布时间：2018-06-27 03:13

本文选题：Al-.Zn-.Mg-.Cu铝合金 + 时效制度　；参考：《中国有色金属学报》2015年04期

【摘要】：采用开路电位、循环极化曲线、电化学阻抗谱及腐蚀形貌表征等研究不同时效制度下Al-6.2Zn-2.3Mg-2.3Cu铝合金分别在3.5%Na Cl(质量分数)以及10 mmol/L Na Cl+0.1mol/L Na2SO4溶液中的电化学腐蚀行为。结果表明:4种时效制度处理后,挤压铝合金耐局部腐蚀能力由大到小的顺序依次为T76+T6、T76、T77、T6。试样在10 mmol/L Na Cl+0.1mol/L Na2SO4溶液中主要发生点蚀,从循环阳极极化曲线上可以观察到明显的点蚀电位和点蚀转换电位;在3.5%Na Cl溶液中发生点蚀和晶间腐蚀。利用点蚀电位φb以及点蚀电位与自腐蚀电位的差值(φb-φcorr)表征局部腐蚀发生的难易程度,自腐蚀电位和再钝化电位的差值(φcorr-φrep)表征局部腐蚀的发展程度。另外,表征了试样的硬度和导电率等性能,发现与峰时效相比,三级时效处理后的合金的硬度并无显著降低,且T76+T6态的硬度稍大于T77态的。可见扩大三级时效的回归时间窗口、降低回归温度,可使合金同时获得更优异的强度和耐蚀性能。
[Abstract]:The electrochemical corrosion behavior of Al-6.2Zn-2.3Mg-2.3Cu aluminum alloy in 3.5 mol / L NaCl solution and 10 mmol / L NaCl 0.1mol / L Na _ 2SO _ 4 solution was investigated by open-circuit potential, cyclic polarization curve, electrochemical impedance spectroscopy and corrosion morphology characterization. The results showed that the order of local corrosion resistance of extruded aluminum alloy was T76 T6, T76 T76T77T7 and T6 after being treated with different aging systems. Pitting corrosion occurred mainly in 10 mmol / L NaCl 0.1 mol / L Na _ 2SO _ 4 solution. The pitting potential and pitting conversion potential were observed from the cyclic anodic polarization curve, and pitting and intergranular corrosion occurred in 3.5% NaCl solution. The pitting potential 蠁 b and the difference between pitting potential and self corrosion potential (蠁 b- 蠁 corr) were used to characterize the degree of difficulty of local corrosion, and the difference between self corrosion potential and repassivation potential (蠁 corr- 蠁 rep) was used to characterize the development of local corrosion. In addition, the hardness and conductivity of the samples were characterized. It was found that compared with peak aging, the hardness of the alloy after three-stage aging treatment was not significantly reduced, and the hardness of T76 T6 state was slightly higher than that of T77 state. It can be seen that by enlarging the regression time window and decreasing the regression temperature, the alloy can obtain more excellent strength and corrosion resistance at the same time.
【作者单位】：中南大学粉末冶金国家重点实验室;中南大学化学化工学院;
【基金】：国家重点基础研究发展计划资助项目(2012CB619502,2010CB731701) 国家自然科学基金重点资助项目(51134007);国家自然科学基金资助项目(51201186) 湖南省自然科学基金资助项目(12JJ6040) 国家重大科研仪器设备研制专项资助项目(51327902)
【分类号】：TG174.36

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