An international team of researchers have developed a nanocomposite of graphene and copper that is 500 times stronger than pure metal. A related material, which fuses graphene and nickel, is 180 times stronger. The scientists, most of them hailing from Korea Advanced Institute of Science & Technology (KAIST; Daejeon, Korea) created the material by layering the metal with monolayer graphene. To accomplish that, they used chemical vapor deposition to create what is reportedly the first metal-graphene multilayer composite. If the material succeeds in being commercialized, it could enable the production of components with an unprecedented strength-to-weight ratio.
The researchers tested the materials using micro-compression tests with transmission electronic microscopes and molecular dynamics simulation.
As the researchers explain in an abstract:
Graphene is a single-atomic-layer material with excellent mechanical properties and has the potential to enhance the strength of composites. Its two-dimensional geometry, high intrinsic strength and modulus can effectively constrain dislocation motion, resulting in the significant strengthening of metals. Here we demonstrate a new material design in the form of a nanolayered composite consisting of alternating layers of metal (copper or nickel) and monolayer graphene that has ultra-high strengths of 1.5 and 4.0 GPa for copper-graphene with 70-nm repeat layer spacing and nickel-graphene with 100-nm repeat layer spacing, respectively. The ultra-high strengths of these metal-graphene nanolayered structures indicate the effectiveness of graphene in blocking dislocation propagation across the metal-graphene interface. Ex situ and in situ transmission electron microscopy compression tests and molecular dynamics simulations confirm a build-up of dislocations at the graphene interface.
Previous research to create similar composites of graphene and metal have not been as successful as the KAIST's researchers.
With a tensile strength 200 times stronger than steel, graphene is itself the strongest material known to man. So strong, in fact that a sheet of the material as thick as plastic wrap could withstand an elephant standing on it. As Columbia University professor James Hone has explained, such a sheet would not break unless the elephant's weight was concentrated to an area the size of the tip of a pencil.
In a separate research project, Columbia professors James Hone and Jeffrey Kysar showed that crystalline graphene threads could be stitched together to for structures nearly as strong as pure crystalline graphene.