Effect of Ag addition on the elevated-temperature mechanical properties of an extruded high strength Mg-Gd-Y-Zr alloy

Elevated-temperature mechanical properties of the extruded Mg-8.5Gd-2.5Y-0.5Zr (wt%) and Mg-8.5Gd-2.5Y-0.5Zr-2Ag (wt%) alloys were investigated by the shear punch test (SPT) in the temperature range of 25-300 degrees C. The average sizes of the dynamically recrystallized grains of the Ag-free and Ag-containing alloys were about 8 and 3 mu m, respectively. Addition of Ag to the base alloy led to the formation of a new intermetallic phase with a composition close to Mg16Gd2YAg, and increased the volume fraction of the second phase particles from 2.5% to about 13%. This together with the refinement of microstructure resulted in superior mechanical properties of the Ag-containing alloy over the base material in the whole temperature range studied. (C) 2014 Elsevier B.V. All rights reserved.