Strengthening effect induced by interfacial reaction in graphene nanoplatelets reinforced aluminum matrix composites

GNPs/Al composites with the different volume fractions of GNPs (0.3, 0.6, 0.9 and 1.2 vol %) were successfully fabricated by spark plasma sintering. Microscopy observation indicated that interfacial Al4C3 phases take on nano-rod or granulate with a mean diameter of similar to 30 nm. Nano-sized Al4C3 phases are uniformly distributed and intimately contacted with GNPs. The interfacial bonding state between GNPs and Al matrix changes from mechanical bonding to strong chemical bonding, because Al4C3 phases are tightly locked into Al matrix forming an anchor effect. The strengthening effect induced by interfacial reaction in GNPs/Al composites was investigated according to grain refinement strengthening, Orowan strengthening, dislocation strengthening by CTE mismatch and load transfer. It is innovatively proposed that GNPs and nano-sized Al4C3 phase should be taken as a whole to discuss the strengthening effect in GNPs/Al composites. Load transfer in GNPs/Al composites is significantly affected by interfacial nanosized Al4C3 phases. Due to the deformation strengthening of Al matrix during tension and the anchor effect of Al4C3 phase, load transfer calculated from the experimental value is one-to twofold higher than its theoretical maximum. This work can provide some meaningful suggests for revealing the strengthening behavior of GNPs reinforced metal matrix composites. (C) 2020 Elsevier B.V. All rights reserved.