Microstructure, Mechanical and Corrosion Properties of Mg-Gd-Zn Alloys

Abstract

Microstructure, mechanical and corrosion properties of Mg-10Gd-2Zn and Mg-10Gd-6Zn (all in wt.%) were evaluated in the as-cast condition. The microstructures of both alloys contained (Mg, Zn)3Gd phase at the interdendritic regions and long period stacking ordered (LPSO) phase distributed in the matrix. The Mg-10Gd-6Zn alloy consisted of a high volume fraction of (Mg,Zn)3Gd intermetallic phases continuously distributed along the grain boundaries. The tensile properties, especially the elongation to failure of the Mg-10Gd-6Zn alloy were slightly lower than those of Mg-10Gd-2Zn. An enhancement in creep resistance was observed with Mg-10Gd-2Zn alloy with the post creep tested microstructure showing dynamic precipitation. Corrosion studies indicated that increased Zn content, from 2 to 6 % in Mg-10Gd alloys, significantly reduced the corrosion resistance.