Dual-heterostructure-enabled mechanical property enhancement and coordinated deformation mechanisms in laminated Mg composite alloys

A laminated Mg-Zn/Mg–Ca composite sheet with dual heterostructures have been fabricated via accumulative roll bonding and annealing. This architecture introduces heterogeneities in both grain sizes and textures. The key lies in the engineered transition zones near hetero-interfaces, which serve a dual function: they coordinate plastic strain via non-basal slip and hetero-deformation induced (HDI) hardening, while the interfaces themselves enhance damage tolerance by crack deflection and blunting. This work elucidates the coupled mechanisms where strain gradients and interfacial transition zones collectively govern plastic compatibility and damage evolution, providing a new design principle for high-performance Mg alloys via heterostructure engineering.