Effect Of Micro-Alloying Element La On Corrosion Behavior Of Al-Mg-Si Alloys

The effect of micro-alloying element La on the corrosion behavior of Al-Mg-Si alloys in 3.5 wt. % NaCl solution was investigated. The results demonstrate that micro-alloying La causes the formation of a microstructure with discrete short-rod like Si particles and Mg2Si particles with a La-rich surface shell. The La-rich shell slows down the dissolution of the Mg2Si particles and mitigates the localized corrosion around the Mg2Si particles. The isolated Si particles hinder the corrosion propagation along grain boundaries. As a result, micro-alloying element La causes a significant improvement in the corrosion resistance of Al-Mg-Si alloys.