Corrosion behavior of Al–Mg2Si alloys with/without addition of Al–P master alloy.

Corrosion resistance is an important fact to be considered in practical engineering application of Al–Mg 2 Si alloys, besides the mechanical properties. So in the paper, corrosion behavior of Al–20%Mg 2 Si with/without Al–3%P master alloy in 3.5% NaCl solution was investigated. For the Al–20%Mg 2 Si alloy, Mg 2 Si acts as anode and corrosion starts from its surface at the initial stage of corrosion process. As the corrosion proceeds, electrochemical polarity converts between Mg 2 Si and α (Al), which results in the corrosion of Al matrix with the formation of pits. Moreover, after addition of Al–3%P master alloy, Mg 2 Si transforms from enormous dendrite to fine and uniformly distributing polyhedron, which inhibits the corrosion pits from propagating in Al matrix and enhances the corrosion resistance of Al–20%Mg 2 Si. [ABSTRACT FROM AUTHOR]