Influence of Ce content on the microstructures and tensile properties of Mg-1Gd-0.5Zn alloys

The microstructures and tensile properties of extruded Mg-1Gd-0.5Zn-xCe sheets with various Ce contents (0, 0.3, 0.7 and 1.2 wt%) were investigated at room temperature. Ce addition refined the grain size and resulted in the formation of new Mg12Ce phases. The volume fraction of Mg12Ce phases increased with the increase of Ce additions, which impeded the growth of dynamic recrystallized grains during extrusion and consequently led to the texture weakening of Mg-1Gd-0.5Zn based sheets. Grain refinement and massive Mg12Ce phases provided the highest strength in the Mg-1Gd-0.5Zn sheet with 1.2 wt% Ce addition. Moreover, due to more basal slip, pyramidal slip activity and uniform strain distribution, the ductility of extruded Mg-1Gd-0.5Zn sheet with 0.3 wt% Ce addition along the extrusion direction exhibited the maximum value of 33.6%, which was approximately 17.9% higher than that of the Mg-1Gd-0.5Zn sheet. However, with the further increase of Ce additions (0.7 and 1.2 wt%), the ductility of the sheets deteriorated gradually, which was associated with the increase of coarse Mg12Ce particles.

Automated summary

The addition of Ce refines the grain size and forms new Mg12Ce phases, leading to an increase in strength but decrease in ductility of Mg-1Gd-0.5Zn based sheets. An appropriate amount of Ce can improve the strength and ductility of the sheets, but excessive Ce content should be avoided to prevent deterioration in ductility.