Tensile fracture behavior of aging hardened Mg-1Ca and Mg-1Ca-1Zn alloys

The tensile properties and fracture characteristics of the peak-aged Mg-1.0 wt.% Ca and Mg-1.0 wt.% Ca-1.0 wt.% Zn alloys, have been investigated in the temperature range 295-450 K. In this temperature range the tensile strength of the Mg-1Ca alloy linearly diminishes by 20%. However the drop in the tensile strength for the Mg-1Ca-1Zn alloy is smaller. The results indicate that the precipitates formed in the Mg-1Ca-1Zn alloy retain their strengthening potential up to similar to 450 K. Microstructure observations using scanning electron microscopy revealed that the failure mode for both alloys is transgranular combined with intergranular rupture, irrespective of the treatment and test temperature. The fractography analyses showed that the transgranular fracture changed from quasi-cleavage to dimple rupture with increasing temperature. (C) 2008 Elsevier B.V. All rights reserved.