Effects of calcium and rare-earth elements on the microstructure and tension-compression yield asymmetry of ZEK100 alloy

Variations of the Mg-Zn-Zr alloy ZK100 were cast and extruded containing rare-earth elements and different amounts of Ca (0.4 and 0.8 wt%). After extrusion and heat treatment, the tensile and compressive mechanical properties of the alloys were evaluated at room temperature. The effects of calcium and rare-earth elements on the microstructure, texture and tension-compression yield asymmetry of the ZEK100-based alloys were studied. The microstructural investigation revealed fine and uniformly distributed Mg-Ca and Mg-RE precipitates throughout the volume of the specimens. A weak texture and a fully recrystallized and homogeneous grain structure were observed in the ZEK100-Ca alloys. The reduced yield asymmetry of the ZEK100-Ca alloys is attributed to the fine grain size, the weak texture, and the small precipitates of these alloy variants. (C) 2014 Elsevier B.V. All rights reserved.