Effect of crystal orientations and precipitates on corrosion behavior of Al-Cu-Li single crystals
(1. Faculty of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, China;
2. Dongguan Eontec Co., Ltd., Dongguan 523662, China;
3. Engineering Research Center of Continuous Extrusion, Ministry of Education, Dalian Jiaotong University, Dalian 116028, China)
2. Dongguan Eontec Co., Ltd., Dongguan 523662, China;
3. Engineering Research Center of Continuous Extrusion, Ministry of Education, Dalian Jiaotong University, Dalian 116028, China)
Abstract: The effect of the crystal orientations and precipitates on the corrosion behavior of Al-Cu-Li single crystals was studied by scanning electron microscopy, transmission electron microscopy, optical microscopy, immersion testing in exfoliation corrosion solution, and electrochemical testing. The results show that the corrosion rates of different orientations of the aged Al-Cu-Li alloy increase in the order of (001) < (101) < (111), which are different from those of the as-quenched alloy in the increasing order of (111) < (001) < (101). The precipitation of the T1 phase deteriorated the corrosion resistance of the Al-Cu-Li alloy, and the degree of deterioration differed in different crystal plane orientations. The severe localized corrosion of the aged alloy propagates along the crystallography and extends along the {111}Al plane in the form of corrosion bands.
Key words: aluminum alloys; single crystal; corrosion; crystal orientation; precipitates