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

ABSTRACT

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 ∼251 MPa, tensile strength of ∼393 MPa and elongation of ∼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.

GRAPHICAL ABSTRACT

IMPACT STATEMENT

The heterogeneous lamella-structure leads to sustained strain-hardenability in Mg-alloy with unique accommodating deformation modes (extensive abnormal <c+a> slips and feather-shaped twins), induced by grain-boundary disclinations and intergranular slip transfers.

KEYWORDS:

• Mg-alloy
• heterogeneous lamella-structure
• strength-ductility synergy
• deformation behavior

Acknowledgement

We would like to thank Prof. Chao Xu from Harbin Institute of Technology for the TEM work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Financial supports from The National Natural Science Foundation of China (Nos. 51922048, 51871108, 52171116 and U19A2084) are greatly acknowledged. Partial financial support came from  Interdisciplinary Integration and Innovation Project of JLU (JLUXKJC2021ZZ08), The Science and Technology Development Program of Jilin Province (No. 20200201002JC), and The Fundamental Research Funds for the Central Universities, JLU.  We would like to thank Prof. Chao Xu from Harbin Institute of Technology for the TEM work.