Correlation between artificial aging and intergranular corrosion sensitivity of a new Al-Cu-Li alloy sheet

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• 作者：Q. Liu ; R.-H. Zhu ; D.-Y. Liu ; Y. Xu ; J.-F. Li ; Y.-L. Chen ; X.-H. Zhang and Z.-Q. Zheng
• 刊名：Materials and Corrosion
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：68
• 期：1
• 页码：65-76
• 全文大小：2053K
• ISSN：1521-4176

文摘

The intergranular corrosion (IGC) sensitivity of an Al-3.81Cu-1.28Li-X alloy with T6 aging for different time at 150, 175, and 200 °C was investigated. With aging, the alloy potential lowers due to precipitation, accompanied with coarsening and discontinuous distribution of grain boundary precipitates, which contributes to corrosion evolution with aging time. Corrosion mode evolution with aging stage (corresponding to hardness evolution) at aging temperature of 150 and 175 °C follows the following order: pitting and local IGC (early aging), general IGC (under-aged), local IGC with pitting (near peak-aged), and pitting (over-aged). At elevated aging temperature of 200 °C, the corrosion mode evolves much faster. IGC only appears in the intensively under-aged stage, but the later under-, peak-, and over-aged stage are featured with pitting corrosion. As IGC occurs, its depth is initially increased and then decreased with aging time.