Optimizing the interface bonding in Cu matrix composites by using functionalized carbon nanotubes and cold rolling

摘要

Nonuniform dispersion and weak interfacial bonding between carbon nanotubes ( CNTs) and Cu matrix are two critical issues for achieving high strength and good ductility of CNT/ Cu composites. Here, acid- treated CNTs precoated with Ni coatings were used to enhance the dispersion uniformity of CNTs and interfacial bonding between CNTs and Cu matrix in the CNT/ Cu composites fabricated through spark plasma sintering and subsequently cold rolling. Scanning electron microscopy analysis revealed the homogeneous dispersion of Nicoated CNTs ( Ni- CNTs) in the composite compared with uncoated CNTs. Transmission electron microscope observation indicated that Cu2O nanoparticles were in situ formed at the interface in Ni- CNT/ Cu composite, where CNTs were uncovered by Ni coatings. After rolling, the distribution of Ni- CNTs transformed into ribbons aligning along the rolling direction. The ultimate tensile strength ( UTS) of 261 MPa was achieved in rolled 1 vol% Ni- CNT/ Cu composite, which was 24.3% higher than that before rolling. The UTS of 2 vol% Ni- CNT/ Cu composite obviously decreased, which could be attributed to the agglomeration of Ni- CNTs in the Cu matrix due to the increased volume content.