Microstructure and corrosion behavior of Al-10%Mg2Si cast alloy after heat treatment

The microstructure and corrosion behavior of Al-10%Mg2Si alloy after heat treatment are investigated. For Al-10%Mg2Si in 3.5 wt.% NaCl solution, corrosion of α-Al phase initiates in (Al + Mg2Si) binary eutectic zones with electrochemical polarity change of Mg2Si phase, and expands along the eutectic Mg2Si precipitates. After heat treatment, eutectic Mg2Si transforms from long flakes and rods to short fibers, disks and spheroidized particles. The transformation of eutectic Mg2Si phase suppresses the rapid expansion of corrosion pits, which leads to enhancing the corrosion resistance of Al-10%Mg2Si alloy.