Enhanced yield symmetry and strength-ductility balance of caliber-rolled Mg–6Zn-0.5Zr with ultrafine-grained structure and bulk dimension

This study investigated a caliber-rolled Mg–6Zn-0.5Zr (ZK60) alloy as part of an effort to achieve enhanced mechanical properties and bulk dimension out of lab scale. The caliber-rolled ZK60 alloy presented a high fraction of dynamically recrystallized (DRXed) grains with submicron sizes. The alloy also exhibited simultaneous improvements in strength and ductility in comparison to commercially extruded ZK60 alloys. The ultrafine-grained (UFG) structure and enhanced mechanical properties were attained while maintaining bulk dimension, which was difficult with severe plastic deformation processes. Furthermore, caliber rolling gave rise to nearly symmetric behavior in terms of yielding. These mechanical improvements in the caliber-rolled ZK60 alloy were interpreted in light of its microstructural characteristics, such as UFG structure, DRX, precipitates, basal texture with tilting of c-axes, and activation of mechanical twinning.