Effect of Sn content on the mechanical properties and corrosion behavior of Mg-3Al-xSn alloys
Zhaochen Yu, Qianfei Huang, Wentao Zhang, Chao Luo, Hongyu Guan, Yang Chen, Honggun Song, Zhi Hu, Luc Chassagne
Abstract
Abstract The effect of Sn content on the mechanical properties and corrosion behavior of Mg-3Al-xSn alloys was investigated by SEM-EDXS, XRD, electrochemical measurements, and scanning Kelvin probe force microscopy (SKPFM). The results showed that when the Sn content was 1.4 wt%, Sn dissolved in the α -Mg matrix and then precipitated as an intermetallic compound (Mg 2 Sn). The combined results of mass loss, hydrogen evolution, and electrochemical measurements indicated that Mg-3Al-1Sn had a low corrosion rate. The SKPFM results showed that the Volta potential of Mg 2 Sn particles, Al-Mn, and β -Mg 17 Al 12 phases were 100, 80, and 50 mV higher than the matrix, respectively. Therefore, the Mg 2 Sn phase that formed in Mg-3Al-xSn served as a local cathode due to its high potential, which accelerated microgalvanic corrosion along with the secondary local cathode (Al-Mn). The Sn solution strengthening and secondary phase strengthening (fine Mg 2 Sn particles) improved the mechanical properties of the Mg-3Al-xSn alloys.