Achieving combined high strength and high conductivity in re-processed Cu-Cr alloy

• Autorzy: Olofinjanaa A. O. , Tan K. S.
• Języki publikacji: EN

Abstrakty

EN

achieve the optimum combination for strength and conductivity in copper based alloys. However, precipitation strengthened Cu- alloys are limited to very dilute concentration thereby limiting the volume proportion hardening precipitates. In this work, we report the investigation of the reprocessing of higher Cr concentration Cu- based alloys via rapid solidification. Design/methodology/approach: The ingot alloys with Cr content up to 10 wt.% were prepared via semi-chilling of small rods before been cast into ribbon using chill block melt spinner. Thermal aging studies followed by conductivity and microhardness tests were performed to follow the HSHC properties. Findings: It is found that the rapid solidification in the as-cast ribbon imposed combined solution extension and ultra-refinement of Cr rich phases. X-ray diffraction evidences suggest that the solid solution extension was up to 6wt%Cr. Lattice parameters determined confirmed the many folds extension of solid solution of Cr in Cu. Thermal aging studies of the cast ribbons indicated that peak aging treatments occurred in about twenty minutes. Peak aged hardness ranged from about 200 to well over 300Hv. The maximum peak aged hardness of 380Hv was obtained for alloy containing 6wt.%Cr but with conductivity of about 50%IACS. The best combined strength/conductivity was obtained for 4wt.%Cr alloy with hardness of 350HV and conductivity of 80% IACS. The high strengths observed are attributed to the increased volume proportion of semi-coherent Cr rich nano-sized precipitates that evolved from the supersaturated solid solution of Cu-Cr that was achieved from the high cooling rates imposed by the ribbon casting process Research limitations/implications: The rapid overaging of the high Cr concentration Cu-Cr alloy is still a cause for concern in optimising the process for reaching peak HSHC properties. It is still important to investigate a microstructural design to slow or severely restrict the overaging process. Originality/value: The optimum HSHC property reported here is a rare combination of high strength (>350Hv ~ 900MPa) and conductivity (50 – 80% IACS) found in metallic alloys.

Słowa kluczowe

EN

metallic alloy; copper alloy; mechanical properties; electric properties; ageing; precipitation hardening

PL

stop metalowy; stop miedzi; właściwości mechaniczne; właściwości elektryczne; starzenie; utwardzanie strąceniowe

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2009
• Tom: Vol. 35, nr 1
• Strony: 14--20
• Opis fizyczny: Bibliogr. 18 poz., rys., tabl.

Twórcy

autor

Olofinjanaa A. O.

autor

Tan K. S.

• Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, BE1410, Brunei Darussalam,

Bibliografia

• [1] K. Han, R. P. Walsh, A. Ishmaku, V. Toplosky, L. Brando, J.D. Embury, High Strength and high electrical conductivity of bulk Cu, Philosophical Magazine 84/34 (2004) 3705- 3716.
• [2] P. Liu, J. Su, Q. Dong, H. Li, Optimization of aging treatment in lead frame copper alloy by intelligent technique, Materials Letters 59 (2005) 3337-3342.
• [3] J. P. Strobrawa, Z. Rdzawski, Precipitation process of the Ni3Al phase in copper-based alloys, Journal of Achievements in Materials and Manufacturing Engineering 15 (2006) 21-26.
• [4] W. Ozgowicz, E. Kalinowska-Ozgowicz, B. Grzegorczyk, The influence of the temperature of tensile test on the structure and plastic properties of copper alloy type CuCr1Zr, Journal of Achievements in Materials and Manufacturing Engineering 29/1 (2008) 143-146.
• [5] J. P. Strobrawa, Z. Rdzawski, W.J. Gluchowski, Microstructure and properties of nanocrystalline copper - Yttria microcomposites, Journal of Achievements in Materials and Manufacturing Engineering 24/1 (2007) 83-86.
• [6] N. Gao, E. Huttunen-Saarivirta, T. Tianen, and M. Hemmila, Influence of prior deformation on the age hardening of a phosphorus-containing Cu–0.61wt.% Cr alloy, Materials Science and Engineering A342 (2003) 270-278.
• [7] J. Su, Q. Dong, P. Liu, H. Li, B. Kang, Research on aging precipitation in a Cu-Cr-Zr-Mg alloy, Materials Science and EngineeringA392 (2005) 422-426.
• [8] J. B. Correia, H. A. Davies, C. M. Cellars, Strengthening in rapidly solidified age hardened Cu-Cr and Cu-Cr-Zr alloys,Acta Materiala 45 (1997) 177-190.
• [9] J. Strobrawa, Z. Rdzawski, Deformation behaviour of dispersion hardened nanocrystalline copper, Journal of Achievements in Materials and Manufacturing Engineering 17 (2006) 153-156.
• [10] M. A. Morris, D. G. Morris, Microstructures and mechanical properties of rapidly solidified Cu-Cr alloys, Acta Metallurgica 35 (1987) 2511-2522.
• [11] P. Liu, B. X. Kang, X. G. Cao, J. L. Huang, H. C. Gu, Strengthening mechanisms in a rapidly solidified and aged Cu-Cr alloy Journal of Materials Science 35 (2000) 1691- 1694.
• [12] F. Lopez, J. Reyes, B. Campillo, G. Aguilar, J. A. Juarez-lslas, Rapid solidification of copper alloys with high strength and high conductivity, Journal of Materials Engineering and Performance6 (1997) 611-614.
• [13] J. Strobrawa, Z. Rdzawski, Dispersion strengthened nanocrystalline copper, Journal of Achievements in Materials and Manufacturing Engineering 24/1 (2007) 35-41.
• [14] E. Botcharova, M. heilmaier, J. Freudenberger, G. Drew, D. Kudashow, U. Martin, L. Schultz, Supersaturated solid solution of niobium in copper by mechanical alloying, Journal of Alloys and Compounds 351 (2003) 119-125.
• [15] A. O. Olofinjana, Evaluating the mechanical properties of metallic glass wires by nano-indentation, Journal of Achievements in Materials and Manufacturing Engineering 22/1 (2007) 39-42.
• [16] J. Dutta Majumdar, I. Manna, Laser surface alloying of copper with chromium, Materials Science and Engineering A268 (1999) 215-226.
• [17] A. Bell and H. A. Davies, Solid solubility extension in Cu-V and Cu-Cr alloys produced by chill block melt-spinning,Materials Science and EngineeringA 226-228 (1997) 1039-1041.
• [18] H. Fernee, J. Nairn, A. Atrens, Precipitation hardening of Cu-Fe-Cr alloys part I, Journal of Materials Science 36 (2001) 2711 - 2719.