Coordinated matrix deformation induced ductility in multilayer graphene/aluminum composites

A new strategy to improve strength and ductility by coordinated deformation mechanism of multilayer graphene (MLG) in graphene/aluminum composite was proposed, and the coordinated deformation induced ductility in MLG/Al composite by in-situ tensile tests in this work. Fabricated by a three-step powder metallurgy routes, including flaky ball-milling, horizontal sintering by spark plasma sintering and vertical hot-extrusion, the microstructure of densely distributed MLG with aligned orientation in aluminum matrix was achieved in the MLG/Al composite to take full advantage of MLG in enhancing ductility. Besides 22% and 15% increment in yield and tensile strength, the composite exhibited exciting 11% increment in ductility, which originated from good uniform elongation (6.8%) and especially excellent post-necking elongation (9.5%) which was increased 69% than that of the Al matrix. The evolution behavior of graphene during deformation was analyzed by in-situ TEM. In-situ analysis revealed that the premature fracture before necking was suppressed by rotation and straightening of MLG, while the post-necking elongation was improved substantially by the crack bridging, interlayer sliding and asynchronous delamination fracture of the MLG. Distinguished to the traditional charac-teristics of dimples, fractured MLGs were mainly distributed along tear ridge of Al dimple with a novel cicada wings-like morphology attributed to the coordinated deformation behavior.

Automated summary

A new strategy to improve strength and ductility by coordinated deformation mechanism of multilayer graphene in graphene/aluminum composite was proposed.