Regulation of the interfacial structure in CNTs/Cu composites by chemical vapor deposited WC to enhance mechanical properties and conductivity

On the premise of ensuring the structural integrity of reinforcement, optimizing the microstructure of interfaces can be an effective method to improve the comprehensive performance of composites. In this study, carbon nanotubes (CNTs) were pre-coated with ammonium metatungstate, and methane was utilized as carbon source for the creative synthesis of WC nanoparticles on intact CNTs (WC@CNTs) through chemical vapor deposition. The WC@CNTs/Cu composites were prepared by regulating the morphology and distribution of WC on CNTs through powder metallurgy. The results demonstrated a significant enhancement of dispersion uniformity of WC@CNTs within Cu matrix. A specific orientation relationship was observed between WC and CNTs as well as Cu, namely ( 111 ) Cu ∥ ( 001 ) WC and ( 100 ) WC ∥ ( 002 ) CNTs , indicating that the introduction of interfacial WC can achieve robust interfacial bonding. This not only effectively enhanced the load transfer capacity of WC@CNTs by restraining interfacial sliding, but also improved the fracture toughness of the composite through crack deflection and bifurcation. The tensile strength of the WC@CNTs/Cu composite reached 272 MPa, exhibiting a 24.8 % and 18.3 % increase compared to that of pure Cu and CNTs/Cu composite, while maintaining a fracture elongation of 29.4 %. Furthermore, the robust interface bonding can also enhance the electrical and thermal conductivity of the composites by reducing interface scattering. The highest electrical and thermal conductivity of WC@CNTs/Cu composites was 95.9 ± 0.7 %IACS and 390 ± 7 W/mK, respectively, which was 1.9 % and 17.8 % higher than that of CNTs/Cu composite. The method employed in this study can offer valuable insights for interface optimization of nanocarbon reinforced metal matrix composites.