Microstructure and mechanical properties of Mg–8Li–xAl–0.5Ca alloys

The effect of the Al content on the microstructure and mechanical behaviour of Mg–8Li–xAl–0.5Ca alloys is investigated. The experimental results show that an as-cast Mg–8Li–0.5Ca alloy is mainly composed of α-Mg, β-Li and granular Mg2Ca phases. With the addition of Al, the amount of α-Mg phase first increases and then decreases. In addition, the intermetallic compounds also obviously change. The microstructure of the test alloys is refined due to dynamic recrystallisation that occurs during extrusion. The mechanical properties of extruded alloys are much more desirable than the properties of as-cast alloys. The as-extruded Mg–8Li–6Al–0.5Ca alloy exhibits good comprehensive mechanical properties with an ultimate tensile strength of 251.2 MPa, a yield strength of 220.6 MPa and an elongation of 23.5%.