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http://dx.doi.org/10.9766/KIMST.2019.22.4.492

A Study on the Microstructure and Anisotropic Mechanical Properties of Oxygen-Free Copper Fabricated by Equal Channel Angular Pressing  

Lee, Jaekun (2nd Research Division, Research and Development Institute)
Hong, Younggon (Department of Materials Science and Engineering, Pohang University of Science and Technology)
Kim, Hyoungseop (Department of Materials Science and Engineering, Pohang University of Science and Technology)
Park, Sunghyuk (School of Materials Science and Engineering, Kyungpook National University)
Publication Information
Journal of the Korea Institute of Military Science and Technology / v.22, no.4, 2019 , pp. 492-500 More about this Journal
Abstract
Equal channel angular pressing(ECAP) is a severe plastic deformation technique capable of introducing large shear strain in bulk metal materials. However, if an ECAPed material has an inhomogeneous microstructure and anisotropic mechanical properties, this material is difficult to apply as structural components subjected to multi-axial stress during use. In this study, extruded oxygen-free copper(OFC) rods with a large diameter of 42 mm are extruded through ECAP by route Bc up to 12 passes. The variations in the microstructure, hardness, tensile properties, and microstructural and mechanical homogeneity of the ECAPed samples are systematically analyzed. High-strength OFC rods with a homogeneous and equiaxed-ultrafine grain structure are obtained by the repeated application of ECAP up to 8 and 12 passes. ECAPed samples with 4 and 8 passes exhibit much smaller differences in terms of the average grain sizes on the cross-sectional area and the tensile strengths along the axial and circumferential directions, as compared to the samples with 1 and 2 passes. Therefore, it is considered that the OFC materials, which are fabricated via the ECAP process with pass numbers of a multiple of 4, are suitable to be applied as high-strength structural parts used under multi-axial stress conditions.
Keywords
ECAP; OFC; Anisotropy; Mechanical Property;
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Times Cited By KSCI : 1  (Citation Analysis)
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1 R. Z. Valiev, “Nanostructuring of Metals by Severe Plastic Deformation for Advanced Properties,” Nat. Mater., Vol. 3, No. 8, pp. 511-516, 2004.   DOI
2 R. Z. Valiev, Y. Estrin, Z. Horita, T. G. Langdon, M. J. Zechetbauer, Y. T. Zhu, “Producing Bulk Ultrafine-Grained Materials by Severe Plastic Deformation,” JOM, Vol. 58, No. 4, pp. 33-39, 2006.   DOI
3 R. Z. Valiev, R. K. Islamgaliev, I. V. Alexandrov, “Bulk Nanostructured Materials from Severe Plastic Deformation,” Prog. Mater. Sci., Vol. 45, No. 2, pp. 103-189, 2000.   DOI
4 R. Z. Valiev, I. V. Alexandrov, Y. T. Zhu, T. C. Lowe, “Paradox of Strength and Ductility in Metals Processed by Severe Plastic Deformation,” J. Mater. Res., Vol. 17, No. 1, pp. 5-8, 2002.   DOI
5 K. H. Song, H. S. Kim, W. Y. Kim, "Enhancement of Mechanical Properties and Grain Refinement in ECAP 6/4 Brass," Rev. Adv. Mater. Sci., Vol. 28, pp. 158-161, 2011.
6 E. A. El-Danaf, M. S. Soliman, A. A. Almajid, M. M. El-Rayes, “Enhancement of Mechanical Properties and Grain Size Refinement of Commercial Purity Aluminum 1050 Processed by ECAP,” Mater. Sci. Eng., A, Vol. 458, No. 1, pp. 226-234, 2007.   DOI
7 A. P. Zhilyaev, T. G. Langdon, “Using High-Pressure Torsion for Metal Processing: Fundamentals and Applications,” Prog. Mater. Sci., Vol. 53, No. 6, pp. 893-979, 2008.   DOI
8 R. Kapoor, A. Sarkar, R. Yogi, S. K. Shekhawat, I. Samajdar, J. K. Chakravartty, "Softening of Al During Multi-Axial Forging in a Channel Die," Mater. Sci. Eng., A, Vol. 560, pp. 404-412, 2013.   DOI
9 M. Shaarbaf, M. R. Toroghinejad, “Nano-Grained Copper Strip Produced by Accumulative Roll Bonding Process,” Mater. Sci. Eng., A, Vol. 473, No. 1-2, pp. 28-33, 2008.   DOI
10 W. J. Kim, K. E. Lee, S. H. Choi, “Mechanical Properties and Microstructure of Ultra Fine-Grained Copper Prepared by a High-Speed-Ratio Differential Speed Rolling,” Mater. Sci. Eng., A, Vol. 506, No. 1-2, pp. 71-79, 2009.   DOI
11 R. Z. Valiev, T. G. Langdon, “Principles of Equal-Channel Angular Pressing as a Processing Tool for Grain Refinement,” Prog. Mater. Sci., Vol. 51, No. 7, pp. 881-981, 2006.   DOI
12 W. Kim, H. H. Lee, S. J. Seo, J. K. Lee, T. S. Yoon, H. S. Kim, “Evaluation of Homogeneous Ultra-Fine Grain Refinements via Equal Channel Angler Pressing Process,” Trans. Mater. Process., Vol. 27, No. 4, pp. 222-226, 2018.   DOI
13 M. Kato, "Hall-Petch Relationship and Dislocation Model for Deformation of Ultrafine-Grained and Nanocrystalline Metals," Mater. Trans., JIM, Vol. 55, No. 1, pp. 19-24, 2014.   DOI
14 M. E. Kassner, "Taylor Hardening in Five Power Law Creep of Metals and Class M Alloys," Acta Mater., Vol. 52, pp. 1-9, 2004.   DOI
15 L. S. Toth, C. Gu, "Ultrafine-Grain Metals by Severe Plastic Deformation," Mater. Charact., Vol. 92, pp. 1-14, 2014.   DOI
16 L. Lapeire, J. Sidor, P. Verleysen, K. Verbeken, I. De Graeve, H. Terryn, L. A. I. Kestens, "Texture Comparison between Room Temperature Rolled and Cryogenically Rolled Pure Copper," Acta Mater., Vol. 95, pp. 224-235, 2015.   DOI