Microstructures and properties of graphene nanoplatelets reinforced Cu/Ti3SiC2/C nanocomposites with efficient dispersion and strengthening achieved by high-pressure torsion

Based on the advantages that high-pressure torsion (HPT) can effectively promote the dispersion of reinforcing phases and refine the grain size of the composites, graphene nanoplatelets (GNPs) reinforced Cu/Ti3SiC2/C nanocomposites have been successfully prepared by HPT after powder metallurgy. In this study, microstructures, interfacial bonding, mechanical, and electrical properties of the nanocomposites were systematically analyzed. The results showed that after HPT, the dispersion of GNPs was significantly improved, and the interfaces between matrix and reinforcing phases were clear and well-bonded. The grain size of the nanocomposites was considerably refined, and nanograins with an average grain size of 0.48 μm were obtained. With the increase of HPT turns, the relative density, mechanical, and electrical properties of the nanocomposites were all improved, and the maximum values of microhardness and electrical conductivity reached 302 HV and 3.85 × 107 S/m (65% IACS), respectively. After HPT, the strengthening mechanisms in the nanocomposites derived from synergistic effects including the uniform dispersion of reinforcing phases, refinement strengthening, and dislocation strengthening. This study provides a reference for the dispersion of reinforcing phases and the refinement of grain size in the composites, to improve their comprehensive properties.