The role of intermetallics on the corrosion initiation of twin roll cast AZ31 Mg alloy
The role of intermetallics on the corrosion initiation of twin roll cast AZ31 Mg alloy
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DOI：
10.1149/2.0291509jes
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发表时间：
2015
影响因子：
3.9
通讯作者：
S. Pawar;Xiaorong Zhou;G. Thompson;G. Scamans;Z. Fan
中科院分区：
文献类型：
--
作者：
S. Pawar;Xiaorong Zhou;G. Thompson;G. Scamans;Z. Fan
使用扫描开尔文探针力显微镜 (SKPFM) 和电子显微镜研究了 6 mm 厚双辊铸造 AZ31 镁合金板中微组分相与 α-Mg 基体之间的微电耦合。在合金板的表面/近表面区域观察到枝晶间的β-Mg 17 (Al, Zn) 12 相以及具有玫瑰花状/花状形貌的Al 8 Mn 5 颗粒和Fe颗粒。微组分相对于α-Mg基体表现出的伏特电势差的顺序为：Fe颗粒>Al 8 Mn 5 金属间化合物>β-Mg 17 (Al,Zn) 12 相。 SKPFM 预测的金属间化合物对局部腐蚀引发的敏感性通过在环境温度下自然通气的 3.5% NaCl 溶液中进行的浸泡测试得到了证实。
The micro-galvanic coupling between the microconstituent phases and the α-Mg matrix in the twin roll cast AZ31 Mg alloy sheet of 6 mm thickness has been investigated using scanning Kelvin probe force microscopy (SKPFM) and electron microscopy. The β-Mg 17 (Al, Zn) 12 phase at the interdendritic spaces, along with the Al 8 Mn 5 particles with rosette/flower-shaped morphologies and Fe-particles have been observed in the surface/near-surface region of the alloy sheet. Volta potential differences exhibited by the microconstituents relative to the α-Mg matrix followed the order of Fe-particles> Al 8 Mn 5 intermetallics> β-Mg 17 (Al, Zn) 12 phase. The susceptibility to localized corrosion initiation by the intermetallics predicted from the SKPFM was confirmed by immersion testing conducted in naturally aerated 3.5% NaCl solution at ambient temperature.