Simultaneously enhanced strength and ductility in graphene nanosheet/Al-Cu-Mg nano-laminated composites by incorporating coarse domains

Abstract

A heterogeneous structure by designing soft/hard domains with dramatically different strengths is effective to maintain the high ductility of metals but it sacrifices the yield strength. Here we first demonstrate a simultaneous enhancement of yield strength and tensile elongation by ∼20% in graphene nanosheet (GNS)/Al-Cu-Mg nano-laminated composites, with a tensile strength of ∼687 MPa and elongation over 10%, by designing heterogeneous domains with a little difference. The underlying mechanism was investigated by microstructural characterizations and simulations, and the hetero-deformation-induced hardening and nano-precipitation strengthening were mainly responsible for the strength-ductility synergy. This study broadens the understanding of heterostructured materials in pursuit of extraordinary mechanical properties.

Keywords

• Metal matrix composites (MMCs)
• heterogeneous structure
• hetero-deformation-induced (HDI) hardening
• nano-laminated structure
• precipitation strengthening