The microstructure, texture and mechanical properties of extruded Mg-5.3Zn-0.2Ca-0.5Ce (wt%) alloy

Mg-5.3 wt%Zn alloy microalloyed with 0.2 wt%Ca and 0.5 wt%Ce was extruded, and the microstructure, texture and mechanical properties of the as-extruded alloy were investigated. The undissolved coarse T1′during homogenization treatment stimulated nucleation of dynamic recrystallization (DRX) grains during extrusion. The double microalloying with Ca and Ce promoted the dynamic precipitation, resulting in high density precipitates after hot extrusion. Fine Ca2Mg6Zn3 particles precipitated dynamically at the grain boundaries (GBs) could effectively hinder the grain growth during hot extrusion. A weaker texture in DRXed grains was attributed to the coarse-particle stimulated nucleation (PSN) and pinning of the grain boundaries by fine precipitates. The fine DRXed grains, high density of dislocation in the unDRXed region, and fine dense precipitates gave rise to the improved strength of the as-extruded Mg-Zn-Ca-Ce alloy.