High temperature thermal stability of pure copper and copper–carbon nanotube composites consolidated by High Pressure Torsion

• Published in: Composites. Part A, Applied science and manufacturing Vol. 51; pp. 71 - 79
• Main Authors: Jenei, P., Gubicza, J., Yoon, E.Y., Kim, H.S., Lábár, J.L.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.08.2013; Elsevier
• Subjects: A. Metal–matrix composites (MMCs); A. Nano-structures; Annealing; ANNEALING PROCESSES; Applied sciences; B. High-temperature properties; B. Microstructures; CARBON BASE MATERIALS; COMPOSITES; Consolidation; Copper; COPPER (PURE); cracking; Dispersion hardening metals; ELEVATED TEMPERATURE; energy; Exact sciences and technology; hardness; heat; HIGH PRESSURE; Metals. Metallurgy; Microstructure; MICROSTRUCTURES; Nanostructure; nanotubes; porosity; Powder metallurgy. Composite materials; Production techniques; sampling; Stability; temperature; THERMAL STABILITY; Torsion; TUBE; A. Nano-structures; A. Metal–matrix composites (MMCs); B. Microstructures; B. High-temperature properties; Annealing; Metal matrix composite; Temperature effect; Carbon nanotubes; Mechanical properties; Hardness; Experimental study; Composite material; Dispersion strengthened metal; Thermal stability; Thermal properties; A. Metal-matrix composites (MMCs); Nanocomposite; Porosity; Copper; Microstructure
• ISSN: 1359-835X; 1878-5840
• DOI: 10.1016/j.compositesa.2013.04.007

The thermal stability of ultrafine-grained (UFG) microstructures in pure copper samples and copper–carbon nanotube (CNT) composites processed by High Pressure Torsion (HPT) was compared. The UFG microstructure in the sample consolidated from pure Cu powder exhibited better stability than that developed in a casted Cu specimen. The addition of CNTs to the Cu powder further increased the stability of the UFG microstructure in the consolidated Cu matrix by hindering recrystallization, however it also yielded a growing porosity and cracking during annealing. It was shown that the former effect was stronger than the latter one, therefore the addition of CNTs to Cu has an overall benefit to the hardness in the temperature range between 300 and 1000K. A good agreement between the released heat measured during annealing and the calculated stored energy was found for all samples.