Influence of rare earth on the microstructure and age hardening response of indirect-extruded Mg-5Sn-4Zn alloy

The effects of Ce addition on the microstructure, age hardening response and mechanical properties of an indirect-extruded Mg-5wt.%Sn-4Zn (TZ54) alloy were investigated. Addition of Ce accelerated the aging response with the peak aging time moving from 300 h in TZ54 to 30 h in Mg-5wt.%Sn-4Zn-1Ce (TZE541), while the peak harness was similar to each other. The addition of Ce also caused an increase in the precipitation stability during overageing. Though the tensile strength of extruded TZ54 was improved by the addition of Ce, the tensile strength of the TZE541 was reduced after T6-treatment. The combined mechanical properties of the present as-extruded alloys by solution heat-treatment and artificial aging (T6) were comparable to commercial wrought magnesium alloys.