Folded graphene reinforced nanocomposites with superior strength and toughness: A molecular dynamics study

• Folded graphene is designed and generated with the aid of hydrogenation and pre-compression. • Current molecular dynamics simulation model is experimentally and numerically validated. • The designed folded graphene leads to superior strength and toughness simultaneously in copper nanocomposites. • Pre-compressive strain of folded graphene further improves the strength and toughness of nanocomposites. • Nanocomposites reinforced with folded graphene with more wave and peak numbers exhibit better toughness. Toughness and strength are important material parameters in practical structural applications. However, it remains a great challenge to achieve high toughness and high strength simultaneously for most materials. Here, we report a folded graphene (FG) reinforced copper (Cu) nanocomposite that overcomes the long-standing conflicts between toughness and strength. Intensive molecular dynamics simulations show that the 10% pre-strain-induced four-wave-patterned FG (1.09 wt%) reinforced Cu nanocomposite exhibits simultaneous enhancement in toughness (∼13.59 J/m 2 ), ductility (∼32.38%), and strength (∼9.52 GPa), corresponding to 38.53%, 58.88%, and 2.26% increase, respectively when compared with its counterpart reinforced by pristine graphene (PG). More importantly, the mechanical properties of FG/Cu nanocomposites can be effectively tuned by changing the pre-compressive strain, wave number, and peak number of FG. The toughening and strengthening mechanisms are applicable to other metal materials reinforced by other 2D nanomaterials, opening up a new avenue for developing tough and strong metal nanocomposites.