Effect of micro-alloying Ca on microstructure, texture and mechanical properties of Mg–Zn–Y–Ce alloys

Abstract

Microstructure, texture and mechanical properties of Mg–5Zn-0.3Y-0.2Ce alloys with the addition of trace xCa (x = 0, 0.3, 0.6 wt%) were systematically investigated in this work. The results revealed that more secondary eutectic phases and smaller grain size of as-cast microstructure could be found with increasing Ca content. After hot extrusion, the Ca-free alloy showed a uniformly recrystallized grain structure, while the Ca-containing alloys possessed a bimodal grain structure composed of fine dynamic recrystallized (DRXed) grains with a size of several microns and un-recrystallized coarse grains. EBSD analysis showed that the three extruded alloys had a fiber texture of (0001) basal plane aligned with the extrusion direction. Texture intensity of the DRXed region was weaker than the deformed region. The extruded alloy with the addition of 0.6 wt% Ca exhibited the highest yield strength of 321MPa due to the smallest DRXed grain size, the deformed region with strong basal texture and dense nanosized precipitates.