Improved intergranular corrosion resistance of Al-Mg-Mn alloys with Sc and Zr additions

Al-5.8Mg-0.4Mn with minor alloying additions of Sc and Zr was investigated via electrochemical testing and nitric acid mass loss testing (NAMLT) in order to reveal the influence of Sc and Zr upon sensitization and intergranular corrosion. The Al-Mg-Mn alloys were also analysed using an electron probe microanalyzer, indicating that beta-phase (Al3Mg2) was more likely to precipitate around rectangular or cubic Al6Mn particles. Results reveal that the strength and intergranular corrosion resistance of Al-5.8Mg-0.4Mn was improved by the combined addition of Sc and Zr. The Al-3(Sc1-xZrx) dispersoids can lead to an alteration of the relative proportion of low angle grain boundaries, and lower volume fraction of beta-phase was observed for Al-5.8Mg-0.4Mn-xSc-yZr relative to the Sc and Zr free alloy.

Automated summary

The influence of Sc and Zr on sensitization and intergranular corrosion in Al-5.8Mg-0.4Mn alloy was investigated. Results show that the addition of Sc and Zr improves the strength and intergranular corrosion resistance of the alloy. The presence of Al-3(Sc1-xZrx) dispersoids alters the proportion of low angle grain boundaries and decreases the volume fraction of beta-phase in the alloy.