Microstructure and Thermal Stability of Copper - Carbon Nanotube Composites Consolidated by High Pressure Torsion

Abstract:

Blends of Cu powders and 3 vol. % carbon nanotubes (CNTs), and an additional sample from pure Cu powder were consolidated by High Pressure Torsion (HPT) at room temperature (RT) and 373 K. The grain size, the lattice defect densities as well as the hardness of the pure and composite materials were determined. Due to the pinning effect of CNTs, the dislocation density is about three times larger, while the grain size is about half of that obtained in the sample consolidated from the pure Cu powder. The increase of the HPT-processing temperature from RT to 373 K resulted in only a slight increase of the grain size in the Cu-CNT composite while the dislocation density and the twin boundary frequency were reduced significantly. The flow stress obtained experimentally agrees well with the value calculated by the Taylor-formula indicating that the strength in both pure Cu and Cu-CNT composites is determined mainly by the interaction between dislocations. The addition of CNTs to Cu yields a significantly better thermal stability of the UFG matrix processed by HPT.

• Periodical: Materials Science Forum (Volume 729)
• Pages: 228-233
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.729.228
• Online since: November 2012
• Authors: P. Jenei, E.Y. Yoon, Jenő Gubicza, Hyoung Seop Kim, J.L. Lábár, Tamás Ungár
• Keywords: Carbon Nanotube (CN), Hardness, High-Pressure Torsion, Microstructure, Thermal Stability

References

[1] R.Z. Valiev, T.G. Langdon, Principles of equal-channel angular pressing as a processing tool for grain refinement, Prog. Mater. Sci. 51 (2006) 881-981.

DOI: 10.1016/j.pmatsci.2006.02.003

[2] A.P. Zhilyaev, T.G. Langdon, Using high-pressure torsion for metal processing: Fundamentals and applications, Prog. Mater. Sci. 53 (2008) 893-979.

DOI: 10.1016/j.pmatsci.2008.03.002

[3] H.J. Choi, J.H. Shin, B.H. Min, J.S. Park, D.H. Bae, Reinforcing effects of carbon nanotubes in structural aluminum matrix nanocomposites, J. Mater. Res. 24 (2009) 2610-2616.

DOI: 10.1557/jmr.2009.0318

[4] H. Li, A. Misra, Y. Zhu, Z. Horita, C.C. Koch, T.G. Holesinger, Processing and characterization of nanostructured Cu-carbon nanotube composites, Mater. Sci. Eng. A 523 (2009) 60-64.

DOI: 10.1016/j.msea.2009.05.031

[5] G. Ribárik, J. Gubicza, T. Ungár, Correlation between strength and microstructure of ball-milled Al–Mg alloys determined by X-ray diffraction, Mater. Sci. Eng. A 387–389 (2004) 343-347.

DOI: 10.1016/j.msea.2004.01.089

[6] L. Balogh, G. Ribárik, T. Ungár, Stacking Faults and Twin Boundaries in fcc Crystals Determined by X-ray Diffraction Profile Analysis, J. Appl. Phys. 100 (2006) 023512.

DOI: 10.1063/1.2216195

[7] P. Jenei, E.Y. Yoon, J. Gubicza, H.S. Kim, J.L. Lábár, T. Ungár, Microstructure and hardness of copper–carbon nanotube composites consolidated by High Pressure Torsion, Mater. Sci. Eng. A 528 (2011) 4690-4695.

DOI: 10.1016/j.msea.2011.02.066

[8] J. Luo, R. Stevens, Porosity-dependence of elastic moduli and hardness of 3Y-TZP ceramics, Ceram. Int. 25 (1999) 281-286.

DOI: 10.1016/s0272-8842(98)00037-6

[9] N.Q. Chinh, J. Gubicza, T.G. Langdon, Characteristics of face-centered cubic metals processed by equal-channel angular pressing, J. Mater. Sci. 42 (2007) 1594-1605.

DOI: 10.1007/s10853-006-0900-3

[10] J. Gubicza, N.Q. Chinh, J.L. Lábár, Z. Hegedűs, C. Xu, T.G. Langdon, Microstructure and yield strength of severely deformed silver, Scr. Mater. 58 (2008) 775-778.

DOI: 10.1016/j.scriptamat.2007.12.028

[11] D.H. Chung, W.R. Buessem, in: F.W. Vahldiek, S.A. Mersol (Eds. ), Anisotropy of Single Crystal Refractory Compounds, vol. 2, Plenum Press, New York, 1968, pp.217-245.

[12] N. Hansen, Hall–Petch relation and boundary strengthening, Scr. Mater. 51 (2004) 801-806.

DOI: 10.1016/j.scriptamat.2004.06.002

[13] D.A. Hughes, N. Hansen, Microstructure and strength of nickel at large strains, Acta Mater. 48 (2000) 2985-3004.

DOI: 10.1016/s1359-6454(00)00082-3

[14] T. Tokunaga, K. Kaneko, Z. Horita, Production of aluminum-matrix carbon nanotube composite using high pressure torsion, Mater. Sci. Eng. A 490 (2008) 300-304.

DOI: 10.1016/j.msea.2008.02.022