Inhibiting GNPs breakage during ball milling for a balanced strength-ductility match in GNPs/Al composites

The difficulty in balancing the structural damage and dispersion of graphene nanoplates (GNPs) during ball milling process has made a great compromise in developing high-performance GNPs/Al composites with a balanced strength-ductility match in large-scale production. Here, we proposed a strategy to inhibit GNPs breakage during the ball milling process by controlling the relative size between GNPs lateral size (d_GNPs) and Al powder diameter (d_Al). The fragmentation of GNPs in as-blended powder was reduced due to the buffering effect of Al powders when d_Al > d_GNPs. The defect density of GNPs was affected by the contact area between GNPs and milling balls, which was closely related to d_GNPs and d_Al. The lateral size and defect density of GNPs showed a combined effect on the mechanical properties of GNPs/Al composites. GNPs/Al composites with 5 vol% GNPs exhibited excellent strength-ductility match with ultimate tensile strength (UTS) of 344 MPa and elongation of over 10%.