Interface optimization of CNT/Cu composite by forming TiC nanoprecipitation and low interface energy structure via spark plasma sintering

摘要

CNT/Cu composite was fabricated by using copper powders within small amounts of titanium nanometer powder via balling milling and followed by spark plasma sintering. Microstructure analysis by SEM, FETEM and EDS shows that laminar grain shape of the composite is inherited from the starting flake powder, and some CNT aggregates are observed at the edge of copper grains. TiC nanoprecipitation, as a transition phase from CNT to metal matrix, is formed in the composites; this phase shows a typical orientation relationship with the Cu matrix, that is Cu (002)//TiC (002). The coherent relationship between TiC and Cu grain reveals the formation mechanism of titanium carbide. Besides, TiC nano-structures contribute to the load transfer of the interface and then the enhancement of the mechanical strength. Furthermore, low angle grain boundary is also revealed by deflecting Moire fringes. It improves the dislocation carrying capacity of the interface. (C) 2017 Elsevier B.V. All rights reserved.