Microstructure, texture and mechanical properties of Mg–Zn–Er alloys containing I-phase and W-phase simultaneously

Abstract

The microstructure, texture and mechanical properties of Mg–9Zn–xEr (x = 3, 4.5 and 6 wt.%) alloys have been investigated. It was found that the main phase compositions of the present Mg–9Zn–xEr alloys were composed of I-phase and W-phase as well as the α-Mg solid solution. The volume fraction of the secondary phases, especially for the W-phase which increased as the content of the Er element increased. The increment in the content of the W-phase led to unexpected results in the associated texture and mechanical properties. The texture was not weakened as the volume fraction of the secondary phase increased compared with those of Mg–Zn–Er alloys containing I-phase or W-phase exclusively, respectively. Whereas, the mechanical properties of as-extruded Mg–9Zn–xEr alloys displayed a tendency to increase with the content of Er increasing. The best mechanical properties had been observed in the Mg–9Zn–6Er alloy after hot extrusion at 300 °C, and the values of the ultimate tensile strength and the elongation were 338 (±5.2) MPa and 13.8 (±1.0)%, respectively. The hot extrusion temperature did not play an important role in influencing mechanical properties.