Hybrid graphene nanoplatelets/multi-walled carbon nanotubes reinforced Cu/Ti3SiC2/C nanocomposites with high efficiency dispersal and strengthening through high-pressure torsion

It is widely accepted to use hybrid reinforcements to prepare metal matrix composites (MMCs). However, it still suffers from some side effects, especially when nano-carbon is used as the reinforcing phase, it tends to agglomerate and then affect its strengthening effects. In the present work, Cu/Ti3SiC2/C nanocomposites reinforced with graphene nanoplatelets (GNPs) as well as multi-walled carbon nanotubes (MWCNTs) achieved combined mechanical along with electrical properties through high-pressure torsion (HPT). For one nanocomposite with 0.8% GNPs-0.2% MWCNTs, after HPT, nano-grains were obtained with the average size of 0.57 μm, which notably achieved grain refinement. With increasing HPT turns, the microhardness and electrical conductivity at N=5 T reached 260.02 HV and 68.3% IACS, which increased by 62.5% and 41.4%, respectively, compared to the samples before HPT. The enhanced performance with HPT on the nanocomposites mainly comes from the homogenization and grain refinement of the microstructure, as well as well-bonded interfaces between Cu matrix and reinforcements. This work provides a reference for preparing composites with balanced mechanical and electrical properties with hybrid reinforcements.