High strength and high ductility achieved in a heterogeneous lamella-structured magnesium alloy

IMPACT STATEMENT The heterogeneous lamella-structure leads to sustained strain-hardenability in Mg-alloy with unique accommodating deformation modes (extensive abnormal slips and feather-shaped twins), induced by grain-boundary disclinations and intergranular slip transfers. By introducing heterogeneous lamella-structure, we obtained a superior strength-ductility synergy in Mg-alloy associated with excellent strain-hardening ability, i.e. yield strength of similar to 251 MPa, tensile strength of similar to 393 MPa and elongation of similar to 23%. By using advanced characterization techniques, we showed that strengthening was mainly caused by the non-uniform distribution of hetero-deformation induced (HDI) stress associated with grain-boundary disclinations, which are mediated by heterogeneous multi-grain interactions. Induced by grain-boundary disclinations and intergranular slip transfers, a variety of abnormal deformation modes have been activated?which contributed significantly to enhanced ductility. This work suggests a new avenue to evade strength-ductility trade-off dilemma in Mg-alloys.

Automated summary

This research has achieved excellent strength-ductility synergy in magnesium alloys by introducing a heterogeneous lamella structure. Strengthening and enhanced ductility were achieved through the non-uniform distribution of hetero-deformation induced stress, grain-boundary disclinations, and intergranular slip transfers. This provides a new approach to address the strength-ductility trade-off dilemma in magnesium alloys.