Preparation and Characteristics of Cu-Al₂O₃ Nanocomposite

F. Shehata, M. Abdelhameed, A. Fathy, M. Elmahdy

.

DOI: 10.4236/ojmetal.2011.12004                

Abstract

Thermo-chemical technique was used to synthesize Cu-Al₂O₃, nanocomposite powders. The process was carried out by addition of Cu powder to aqueous solution of aluminum nitrate. Afterwards, a thermal treatment at 850℃ for 1 hr was conducted to get insitu powders of CuO and stable alumina (Al₂O₃, ). The CuO was reduced in hydrogen atmosphere into copper powder. The nanocomposite powders of both copper and alumina were thoroughly mixed, cold pressed into briquettes and sintered at 850℃ in hydrogen atmosphere. The x-ray diffraction and scanning electron microscope (SEM) with energy dispersive spectrometer (EDS) were used to characterize the structure of the obtained powders. The results showed that alumina nanoparticles (20 nm) and ultra fine copper crystallite (200 nm) were obtained. SEM and EDS showed that the alumina particles were uniformly dispersed within the copper crystallite matrix. The structure also revealed formation of a third phase (CuAlO₂) at copper-alumina interface. The hardness and density results showed that the gain in hardness was found to be dependent on the alumina contents rather than on the relative densities. The alumina content up to 12.5% resulted in an increase of 47.9% in hardness and slight decrease (7.6%) in relative densities. The results of compression tests showed considerable increase in compression strength (67%) as alumina content increased up to 12.5%. The compression strength showed further increase in compression strength (24%) as strain rates were increased from 10^-4 s to 10s. Strain hardening and strain rate parameters “n” and “m” have shown positive values that improved the total strain and they can be used to predict formability of the nanocomposite.

Keywords

Cu-Al₂O₃, Nanocomposite, Thermochemical, Compression, Strain Rate, Strain Hardening

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	D. W. Lee and B. K. Kim, “Nanocomposite Powders for New Contact Materials Based on Copper And Alumina,” Materials Letters, Vol. 58, No. 3-4, 2004, pp. 378-383. doi:10.1016/S0167-577X(03)00505-6
[2]	G. M. Kalinin, S. A. Fabritsiev and B. N, “Specification of Properties and Design Allowable for Copper Alloys Used in HHF Components of ITER,” Journal of Nuclear Materials, Vol. 307-311, 2002, pp. 668-672.
[3]	R. H. Liu, K. X. Song, S. G. Jia, X. F. Xu, J. X. Gao, X. H. Guo, “Morphology and Frictional Characteristics Un- der Electrical Currents of Al2O3/Cu Composites Prepared by Internal Oxidation,” Chinese Journal Aeronautic, Vol. 21, No. 3, 2008, pp. 281-288. doi:10.1016/S1000-9361(08)60037-0
[4]	H. Nasiri, J. Vahdati Khaki and S. M. Zebarjad, “One-Step Fabrication of Cu-Al2O3 Nanocomposite via Solution Com- bustion Synthesis Route,” Journal of Alloys and Com- pounds, Vol. 509, No. 17, 2011, pp. 5305-5308. doi:10.1016/j.jallcom.2011.01.185
[5]	J. R. Groza and J. C. Gibeling, “Principles of Particle Se- lection for Dispersion-Strengthened Copper,” Materials Science and Engineering A, Vol. 171, No. 1-2, 1993, pp. pp. 115-125. doi:10.1016/0921-5093(93)90398-X
[6]	J. R. Weertman, “Structure and Mechanical Behavior of Bulk Nanocrystalline Materials,” MRS Bulletin, Vol. 24, No. 2, 1999, pp. 44-50.
[7]	G. B. Veeresh Kumar, C. S. P. Rao and N. Selvaraj, “Mechanical and Tribological Behavior of Particulate Rein- forced Aluminum Metal Matrix Composites—A Review,” Journal of Minerals & Materials Characterization & En- gineering, Vol. 10, No.1, 2011, pp. 59-91.
[8]	E. T. Thostenson, C. Li and T. W. Chou, “Review: Nano- composites in Context,” Composites Science and Tech- nology, Vol. 65, No. 3-4, 2005, pp. 491-516. doi:10.1016/j.compscitech.2004.11.003
[9]	F. He, Q. Han and M. J. Jackson, “Nanoparticulate Rein- forced Metal Matrix Nanocomposites—A Review,” In- ternational Journal of Nanoparticles, Vol. 1, No. 4, 2008, pp. 301-309.
[10]	R. Ashtana, “Solidification Processing of Reinforced Me- tals,” Transaction Technical Publications, Vol. 151-152, 1997.
[11]	A. Evans, C. San Marchi amd A. Mortensen, “Metal Ma- trix Composites in Industry: An Introduction and a Sur- vey,” Springer, Berlin, 2003. doi:10.1007/978-1-4615-0405-4
[12]	M. Korac, Z. Kamberovic, M. Tasic and M. Gavrillovski, “Nanocomposite Powders for New Contact Materials Based on Copper and Alumina,” Chemical Industry & Chemical Engineering Quarterly, Vol. 14, No. 4, 2008, pp. 215- 218. doi:10.2298/CICEQ0804215K
[13]	P. K. Jena, E. A. Brocchi and M. S. Motta, “Identification of a Third Phase in Cu-Al2O3 Nanocomposites Prepared by Chemical Routes,” Material Science Engineering A, Vol. 371, No. 1-2, 2004, pp. 72-78.
[14]	M. Kora?, Z. An?i?, M. Tasi? and Z. Kamberovi?, “Sin- tering of Cu-Al2O3 Nanocomposite Powders Produced by a Thermochemical Route,” Journal of Serbian Chemistry Society, Vol. 72, No. 11, 2007, pp. 1115-1125.
[15]	F. Shehata, A. Fathy, M. Abdelhameed and S. Moustafa, “Preparation and Properties of Al2O3 Nanoparticle Rein- forced Copper Matrix Composites by In Situ Processing,” Materials & Design, Vol. 30, No. 7, 2009, pp. 2756-2762. doi:10.1016/j.matdes.2008.10.005
[16]	B. D. Cullity, “Elements of X-Ray Diffraction,” 2nd Edi- tion, Addison-Wesley, Boston, 1978, p. 102.
[17]	D. J. Towle and C. M. Friend, “Comparison of Compres- sive and Tensile Properties of Mg Based MMCs,” Mate- rials Science Technology, Vol. 9, No. 1, 1993, pp. 35-41.
[18]	J. Pike, S.W. Chan, F. Zhang, et al., “Formation of Stable Cu2O from Reduction of CuO Nanoparticles,” Applied Catalysis A: General, Vol. 303, No. 2, 2006, pp. 273-277. doi:10.1016/j.apcata.2006.02.008
[19]	S. J. Hwang, “Compressive Yield Strength of the Nano- crystalline Cu with Al2O3 Dispersoid,” Journal of Alloys and Compounds, Vol. 509, No. 5, 2011, pp. 2355-2359. doi:10.1016/j.jallcom.2010.11.017
[20]	C. A. Schuh and T. G. Nieh, “Hardness and Abrasion Re- sistance of Nanocrystalline Nickel Alloys near the Hall- Petch Breakdown Regime,” Proceedings of Symposium I, Nanomaterials for Structural Applications, Boston, 2-6 December 2003, pp. 27-32.
[21]	J. Schiotz, F. D. Di Tolla and K. W. Jacobsen, “Softening of Nanocrystalline Metals at Very Small Grains,” Nature, Vol. 391, No. , 1998, pp. 561-563. doi:10.1016/j.jallcom.2010.11.017
[22]	H. Conrad and J. Narayan “On the Grain Size Softening in Nanocrystalline Materials,” Script Material, Vol. 42, No. 11, 2000, pp. 1025-1030. doi:10.1016/S1359-6462(00)00320-1
[23]	M. Korac, Z. Kamberovic, Z. Andic, M. Filippovic and M. Tasic, “Sintered Materials Based on Alumina and Cop- per Powders Synthesized by a Novel Method,” Science of sintering, Vol. 42, No. 1, 2010, pp. 81-90. doi:10.1016/S1359-6462(00)00320-1