Effect of extrusion on corrosion properties of Mg-2Ca-χAl (χ=0, 2, 3, 5) alloys

Effect of extrusion on the microstructures and corrosion properties of Mg-2Ca-chi Al (chi = 0, 2, 3, 5 wt.%) alloys were investigated in present work. Results showed that the precipitated phase changed from Mg2Ca and (Mg, Al)(2)Ca to Al2Ca with the increase of Al content. Corrosion results indicated that the addition of Al could improve the corrosion resistance of Mg by the formation of protective (Mg, Al)(2)Ca and Al2Ca. The as-cast alloys showed uniform corrosion mechanism while the as-extruded Mg-Al-Ca alloys presented local corrosion characteristic. Above different corrosion mechanisms were illustrated and analyzed.