Improving strength and corrosion resistance of high Mg alloyed Al–Mg–Mn alloys through Ce addition

Micro-alloying is thought to improve the performance of Al–Mg alloys commonly used in transport applications. The effect of Ce addition (not higher than 0.9 wt-%) on the microstructure, corrosion behavior, and mechanical properties of the Al–9.2Mg–0.7Mn alloy was systematically investigated to assess its potential use in engineering applications. Ce addition had a significant effect on pitting corrosion resistance due to its segregation in the Mn-rich phase. In particular, the pitting corrosion rate of the alloy in the sensitization state decreased substantially with Ce addition, and was approximately 48 and 53% lower than that of the alloy matrix with 0.1 and 0.3 wt.% Ce, respectively. In addition, its strength was improved through 0.3 wt.% Ce addition (providing an increase in ultimate tensile strength of approximately 30 MPa) at no expense to intergranular corrosion resistance, indicating that Ce micro-alloying could comprehensively improve the properties of Al–Mg–Mn alloys.