Understanding heterogeneous metal-mediated interfacial enhancement mechanisms in graphene-embedded copper matrix composites

Highlights: • Graphene-Cu interfaces were tuned via alloying heterogeneous elements. • The enhanced interfaces are favourable to improving tensile properties. • The preferable atomic orientation arrangement states were identified. • The underlying interfacial enhancement mechanisms were analysed. Graphene-embedded Cu matrix composites (GE-CMCs), as one of typical versatile functional composite materials, have great potential to be widely utilized in many engineering fields. Unfortunately, one of major issues is the weak interfacial interactions between metallic matrix and carbonaceous graphene, leading to the rapid mechanical failure. In this work, some heterogeneous alloying elements, including Ni, Ti, Mn and Al, are proposed to be incorporated into Cu matrix to re-construct graphene-Cu interface with the attempt to improve tensile properties of GE-CMCs via first-principles calculations. Meanwhile, a systematical investigation is given on the atomic orientation arrangement states to identify the preferable conditions, which reveal that alloying Mn element with Cu matrix with an equal atomic arrangement over the graphene-Cu interface delivers the most robust interfacial bonding ability, thus resulting in obvious strength (364%) and elongation increasement (415%) in comparison with the pristine graphene-Cu interface in GE-CMCs. Furthermore, the electronic structures and the underlying deformation and enhancement mechanisms of Mn-alloyed GE-CMCs are analyzed to verify the presence of enhanced Mn-C bonds over graphene-Cu interfaces as the external strain increases. It is expected that this work opens an avenue to understand the interfacial enhancement mechanisms and offers an effective interfacial optimization strategy via tuning the atomic arrangement orientation states to achieve high-performance tensile performance for GE-CMCs or other graphene-metal composites.