Effect of RE Content on the Fracture Behavior in Mg-Gd-Nd-Zr Alloys
Tensile tests were performed on T4-treated specimens of GN62K (Mg-6Gd-2Nd-Zr(wt%)) and GN112K (Mg-11Gd-2Nd-Zr) alloys at room temperature and on T6-treated ones from room temperature to 300°C. The fracture behavior was investigated by using SEM images of fracture surfaces together with optical metallographs adjacent to the surface. Quasi-cleavage fracture was observed in the fracture surfaces of both alloys in T4-treated condition, and it seems that RE content has no significant effect on the fracture mechanism in T4-treated alloys. As for T6 treated condition, cracking was in a manner of transgranular cleavage and/or quasi-cleavage fracture in GN62K alloy but intergranular fracture in GN112K alloy, which implies that the fracture mechanism in T6-treated Mg-Gd-Nd-Zr alloys can be altered by the amount of RE addition. This phenomenon is interpreted in association with the relative strength of grain bulk and boundary.
Yafang Han et al.
K. Y. Zheng et al., "Effect of RE Content on the Fracture Behavior in Mg-Gd-Nd-Zr Alloys", Materials Science Forum, Vols. 546-549, pp. 199-202, 2007