Microstructure and mechanical properties of extruded Mg–1Ca–1Zn–0.6Zr alloy

The microstructure and tensile property of extruded Mg–1Ca–1Zn–0.6Zr alloy have been examined by means of electron backscattered diffraction, scanning and transmission electron microscopy. A fine microstructure and a typical basal texture are obtained in the extruded alloy which exhibits a yield strength as high as 306 MPa along with a moderate elongation ~11%. The refined as-extruded microstructure is a result of the combination of dynamic recrystallisation and the Zener pinning effect induced by the fine precipitates. Both discontinuous and continuous dynamic recrystallisation are found to be operative in this study. Under tensile stress, cracks nucleate and propagate in the large Mg₂Ca(Zn) particles which are formed during the solidification of casting and retained after extrusion.