Influence of cerium on the microstructure, mechanical properties and corrosion resistance of magnesium alloy

The influence of cerium on the microstructure, mechanical properties and corrosion resistance of AZ91D was investigated. By adding 2% cerium to AZ91D alloy, the ultimate tensile strength and the elongation increased by 19.3% and 104.0%, respectively. This was mainly caused by the refinement of the β phase and the formation of Al4Ce strengthening phase. By adding 2% Ce, the corrosion rate decreased to 21.8% of the AZ91D corrosion rate. The corrosion morphologies indicated that the addition of cerium formed the more continuous β phase, which acted as a corrosion barrier. The Auger depth profiles indicated that the corrosion film on AZ91D + 2% Ce had a two-layer structure: an outer layer and an Al-enriched inner layer. This Al-enriched layer contributes to the improved corrosion resistance of AZ91D.