Fabrication of high strength Cu–NbC composite conductor by high pressure torsion

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2011-01, Vol.528 (3), p.1750-1756
• Main Authors: Long, B.D., Umemoto, M., Todaka, Y., Othman, R., Zuhailawati, H.
• Format: Article
• Language: English
• Subjects: Annealing; ANNEALING PROCESSES; Applied sciences; Composite materials; COMPOSITES; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Conductivity of specific materials; Conductors (devices); Copper; DENSITY; Elasticity. Plasticity; ELECTRICAL CONDUCTIVITY; ELECTRICAL CONDUCTORS; Electrical properties; Electrical resistivity; Electronic transport in condensed matter; Exact sciences and technology; FABRICATION; HARDNESS; HIGH PRESSURE; High strength; High-pressure torsion; Mechanical properties; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metal matrix composites; Metals. Metallurgy; Niobium; Particulate composites; Physics; Powder metallurgy; Powder metallurgy. Composite materials; Production techniques; Resistivity; Technology; TENSILE STRENGTH; Torsion
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2010.11.005

▶ Cu–NbC composite fabricated from elemental powders by high pressure torsion (HPT). ▶ After HPT, sample showed close to full density (>99%) without any further sintering. ▶ NbC was in situ formed in the Cu matrix after 20min of HPT deformation. ▶ Electrical conductivity (EC) increased whilst tensile strength slightly decreased. ▶ A good combination of EC, tensile strength and thermal stability was achieved. A high strength Cu–NbC composite conductor for electrical applications was fabricated from Cu, Nb and C elemental powders using high pressure torsion (HPT). After HPT, samples showed close to full density (>99%). SEM observations revealed that atomic scale mixing occurred in the following order: deformation of Cu particles, the formation of Cu/Nb lamellar structure, fracturing of Nb lamella into sub-micron particles and the formation of uniform structure with fine distribution of Nb particles. The in situ formation of NbC in the copper matrix during HPT was detected. Annealing at 600 and 700°C resulted in substantial increases in microhardness and tensile strength and a slight decrease in electrical conductivity with increasing NbC volume fraction. The best combination of electrical conductivity (54% IACS) and tensile strength (810MPa) ever reported for such a composite was obtained in the Cu–2vol% NbC composite after annealing at 700°C.