Local electrochemical impedance spectroscopy study of the influence of ageing in air and laser shock processing on the micro-electrochemical behaviour of AA2050-T8 aluminium alloy
Local electrochemical impedance spectroscopy study of the influence of ageing in air and laser shock processing on the micro-electrochemical behaviour of AA2050-T8 aluminium alloy
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DOI：
10.1016/j.electacta.2011.01.091
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发表时间：
2011-11
影响因子：
6.6
通讯作者：
H. Krawiec;V. Vignal;Hassan Amar;P. Peyre
中科院分区：
文献类型：
--
作者：
H. Krawiec;V. Vignal;Hassan Amar;P. Peyre
采用局部电化学阻抗谱和场发射扫描电子显微镜/电子能谱（FE-SEM/EDS）研究了抛光后AA 2050-T8在0.1M NaCl溶液中的微观电化学行为。然后研究了在空气和LSP中老化的影响。在空气中老化三个月导致电荷转移电阻的增加。这在电荷转移电阻约为1 M Ω cm 2（而不是抛光后的10− 3 M Ω cm 2）的组成颗粒周围的位置中清楚地观察到。FE-SEM/EDS分析证实了颗粒周围的钝化性增加。另一方面，LSP对基质行为的影响被认为是非常有益的。在空气中老化后，电荷转移电阻和氧化膜电阻分别急剧增加到约0.35MΩ cm 2和1 M Ω cm 2，而在空气中老化后分别为约1.9×10− 3 M Ω cm 2和4.2×10− 3 M Ω cm 2。这归因于LSP处理后试样表面存在压应力。应力值由XRD测量确定。
In the present paper, the micro-electrochemical behaviour of AA2050-T8 in 0.1M NaCl was first studied after polishing by means of local electrochemical impedance spectroscopy and field-emission scanning electron microscopy/electron dispersive spectroscopy (FE-SEM/EDS). The influence of ageing in air and LSP was then investigated. Ageing in air for three months led to an increase in the charge transfer resistance. This was clearly observed in sites surrounding constituent particles where the charge transfer resistance was in the order of 1MΩcm2(instead of 10−3MΩcm2after polishing). Increased passivity around particles was confirmed from FE-SEM/EDS analysis. On the other hand, the effect of LSP on the behaviour of the matrix was found to be extremely beneficial. Both charge transfer and oxide film resistances were sharply increased to approximately 0.35MΩcm2and 1MΩcm2, respectively, as opposed to approximately 1.9×10−3MΩcm2and 4.2×10−3MΩcm2, respectively, after ageing in air. This was attributed to the presence of compressive stresses at the specimen surface after LSP treatment. Stress values were determined from XRD measurements.