Simultaneously improving mechanical and anti-corrosion properties of extruded Mg-Al dilute alloy via trace Er addition

Simultaneously improving the mechanical properties and corrosion resistance of magnesium (Mg) alloys is a long-standing challenge to be solved in their engineering applications. In this work, we find that trace Er addition can improve the mechanical and anti-corrosion properties of Mg-1.4Al-0.4Mn-0.4Ca0.3Er (wt%, AMXE) dilute alloy synergistically, especially reducing the corrosion rate (0.75 mm y -1 ) by one order of magnitude compared with the reference Mg-1.4Al-0.4Mn-0.4Ca (AMX) alloy and making it comparable to that of high-purity Mg. Adding trace Er reduces the dynamic recrystallization degree and increases the strengthening phase particles, which is mainly responsible for the increase of yield strength by 42 MPa. The addition of Er promotes the formation of much less noble Al 8 Mn 4 Er with effective Fe trapping ability and induces dislocation segregation, thus dramatically reducing micro-galvanic corrosion tendency. Meanwhile, Er addition promotes the formation of a more passivation and dense corrosion film. These two factors together lead to the extremely low corrosion rate of AMXE alloy. Our findings are expected to promote the development of low alloyed high performance Mg alloys. (c) 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

In this study, trace Er addition was found to synergistically improve the mechanical and anti-corrosion properties of the Mg-1.4Al-0.4Mn-0.4Ca0.3Er alloy. The corrosion rate of the alloy was reduced by one order of magnitude compared to the reference alloy. This improvement was attributed to the reduction in dynamic recrystallization and the formation of stronger strengthening phase particles. The addition of Er also promoted the formation of a less noble Al8Mn4Er phase with effective Fe trapping ability and induced dislocation segregation, leading to reduced micro-galvanic corrosion.