Influence of Ce micro-alloying on the microstructure and corrosion behavior of sub-rapid solidified Mg-4.5Al-1.5Sn-0.5Ca alloys

Abstract

The effect of Ce micro-alloying (0, 0.05, 0.1 and 0.2 wt.%) on the microstructure and corrosion resistance of as-cast Mg-4.5Al-1.5Sn-0.5Ca (ATX521) alloys was investigated. The results reveal that the corrosion resistance of ATX521-0.1Ce alloy is remarkably improved by one order of magnitude via trace Ce addition in comparison to Ce-free alloy. The reduced electrochemical potential, refined and homogeneously distributed Ce-rich CaMgSn eutectic particles, effectively alleviate micro-galvanic corrosion and block the corrosion propagation. Furthermore, 0.1 wt.% Ce addition improves the compactness and protectiveness of product film, contributing to the enhanced corrosion resistance. The current work proposes a high-efficiency and low-cost route, i.e., sub-rapid solidification combined with Ce micro-alloying, towards fabricating a corrosion-resistant ATX521-0.1Ce alloy with improved mechanical properties.

Keywords

• Magnesium alloy
• Intermetallic
• Rare earth element
• Local corrosion