Superelastic bionic graphene/nanoceramic metamaterials with tunable thermo-mechanical performances

Abstract

Limited by the intrinsic strong bonds between the composing atoms, engineering materials are plagued by the inevitable trade-offs among thermo-mechanical strength, toughness, and stability. In this work, a graphene/nanoceramic metamaterials (GNC) metamaterial was created by in-situ intercalation of Zr(WO4)2 nanoparticles within the multilayered microcell wall of a 3D hyperbolic graphene template. The bionic lamellar feature of the reduced graphene oxide (RGO)-Zr(WO4)2 sheet makes it highly ductile and stiff at the microscale, while the hyperbolic mesoscopic structure of GNC significantly enhanced the resistance to shear slip-induced fracture. 3D lightweight GNC metamaterials, therefore, exhibited synergic improvement in elastic compressibility (90%), strength (1.4 MPa), and toughness (1.62 N/m) than those of reported materials with similar architectures from either individual component or sandwiched microcell. Moreover, due to the lattice rotation of Zr(WO4)2 effectively regulated by the RGO sheet, the 3D GNC demonstrated tunable thermal expansion coefficient (TEC) as near-zero (−1.1 × 10−6 K−1), negative (−11.6 × 10−6 K−1), positive (1.2 × 10−6 K−1), and even combinations of three schemes. The resultant low thermal conductivity (∼0.007 W m−1 K−1), prior thermal shock resistance (200 K/s), and fireproof make GNC metamaterial show promise for applications in extreme conditions, such as lightweight protective filler, thermal insulator, robust damper, fire-retardant coating, thermal stress regulator, etc.