| ELECTROCHEMICAL CORROSION BEHAVIOUR OF Mg-Li AND Mg-Li-Zn ALLOYS Chandra Perugu1; Ashtosh Jangde1; Subodh Kumar1; Satyam Suwas1; 1INDIAN INSTITUTE OF SCIENCE, Bangalore, India; PAPER: 190/Corrosion/Regular (Oral) SCHEDULED: 16:45/Mon. 28 Nov. 2022/Andaman 2 ABSTRACT: Mg-Li based alloys are the lightest alloys and hence, are attractive for aerospace applications [1]. We have optimized Li content as 8 wt% and Zn content as 2 wt% in Mg to obtain tensile properties better than the existing commercial and experimental wrought Mg-Li based alloys. The optimization of alloy composition, processing parameters and tensile properties have already been reported elsewhere [2]. However, the corrosion resistance of Mg-Li alloys is poorer than the other Mg-alloys, which restricts its applications [3]. The 2 wt% Zn addition not only improved the tensile properties of Mg-8Li (LZ80) alloy but also improved its corrosion resistance. Here, we present the electrochemical corrosion behavior of the two cold-rolled alloys, i.e., Mg-8Li and Mg-8Li-2Zn (LZ82). The microstructure of the alloys was examined by scanning electron microscope before and after corrosion tests in order to explain the observed corrosion behaviour. Both the alloys exhibited localized pitting corrosion, but it was less severe in the case of LZ82 alloy. The pitting corrosion initiated at the interface of α-hcp and β-bcc phases due to micro-galvanic coupling between the two phases, and Zn addition lowered the potential difference between these phases, as revealed by scanning Kelvin probe force microscopy. References: [1] I. J. Polmear, Light Alloys [M], Fourth Edition, 1995. [2] C. S. Perugu, G. Ganesh, S. Kumar, S. Suwas, S. Sivam, Proceedings of the 6th Decennial International Conference on Solidification Processing, Old Windsor, U.K., Ed. Z. Fan, 650-653, 2017. [3] D. Cao, Lin Wu, S. Yong, W. Guiling, Lv. Yanzhuo, Journal of Power Sources, 177 (2008) 624–630. |
