LAUSR

Abstract Formation of second phases in as-cast Mg-xNd-0.3Zr (x = 0, 5 and 11) alloys was characterized and the role of second phases on the corrosion resistance was investigated. Mg12Nd second phase with a semi-continuous network along grain boundary was formed in Mg-5Nd-0.3Zr alloy and the formed Mg12Nd second phase acted as corrosion barrier, which improved the corrosion resistance. A higher area fraction of second phase along grain boundary was formed in Mg-11Nd-0.3Zr alloy while the second phase was composed of Mg41Nd5 and Mg12Nd with a lamellar structure. Instead of corrosion barrier, cracks were formed along the second phase during the corrosion process in Mg-11Nd-0.3Zr alloy, which resulted in the fall out of grains and an intergranular corrosion behavior. This result indicated there was a limitation of corrosion barrier effect of second phases in Mg-Nd-Zr alloys.