Study of an Accelerated Aging Process for Conductive Aluminum Alloys

Abstract:

An orthogonal hardness study of 4 factors (the step one aging temperature (T1) and time (t1), and step two aging temperature (T2) and time (t2)) with 3 levels was designed to optimize an accelerated aging process for a newly developed conductive aluminum alloy (Al-0.4wt.%Si-0.3wt.% Mg-0.3wt.%Ce). Statistical analysis of the experimental results indicates that the factor significance ranked from high to low is t2, T2, T1, and t1. The optimal aging process is 140°C×5h+220°C×5h. Experimental validation confirms that all the strength, hardness, elongation and conductivity with the optimized aging process exceed the predictions. Compared with the commonly used T7 process (190°C×20h), the optimized aging process leads to a more superior precipitation effect and much less time. TEM observation indicates the accelerated aging process significantly expedites the precipitating transformation even with much shorter aging time.

• Periodical: Materials Science Forum (Volume 877)
• Pages: 569-574
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.877.569
• Online since: November 2016
• Authors: Hengcheng Liao*, Ye Liu, Qi Gui Wang
• Keywords: Accelerated Aging, Conductive Aluminium Alloy, Hardness, Orthogonal Test, Precipitation

References

[1] S. Karabay, Influence of AlB2 compound on elimination of incoherent precipitation in artificial aging of wires drawn from redraw rod extruded from billets cast of alloy AA-6101 by vertical direct chill casting, Mater. Des. 29(7) (2008) 1364-1375.

DOI: 10.1016/j.matdes.2007.06.004

[2] J. E. Hatch, Aluminum: Properties and physical metallurgy, ASM International, (1984).

[3] L. P. Wang, F. W. Kang, G. Erjun,X. Y. Zhang, Role of Single Rare Earths Ce , La and Mischmetal in Commercial Pure Aluminum, J. Chinese Rare Earth Soc. 21(2) (2003) 218-221.

[4] F. Q. Li, The interaction of borium with the impurity elements in aluminum alloys and it effect on the conductivity, Master degree thesis, Dalian University of Technology, (2003).

[5] S. Karabay, I. Uzman, Inoculation of transition elements by addition of AlB2 and AlB12 to decrease detrimental effect on the conductivity of 99. 6% aluminium in CCL for manufacturing of conductor, J. Mater. Process. Techn., 160(2) (2005) 174-182.

DOI: 10.1016/j.jmatprotec.2004.06.015

[6] H. C. Liao, Y. Liu, C. L. Lü, Q. G. Wang, Effect of Ce addition on castability, mechanical properties and conductivity of Al-0. 3%Si-0. 2%Mg alloys, Int. J. Cast. Metals Res. 28(4) (2015) 213-220.

DOI: 10.1179/1743133615y.0000000002

[7] C. L. Lü, H. C. Liao, Y. Liu, Q. G. Wang, Effect of Ce addition on castability, mechanical properties and conductivity of commercial-purity aluminum, China Foundry 12(4) (2015) 277-284.

[8] G. Z. Gao, Y. W. He, J. Z. Chen, Influence of rare earth on conductivity of aluminum conductors, Chinese J. Nonferrous Met. 2(1) (1992) 78-81.

[9] Y. H. Xu, S. L. Wang, S. Tian, F. M. Du, X. P. Zhou, F. S. Ni, Effect of Ce on the aging of AlMgSi alloy by resistance measurement, J. Rare Earths 13 (3) (1995) 186-189.

[10] N. Q. Zhao, J. X. Yao and X. J. Yang, Effect of Rare Earth on Microstructure and Properties of 6063 Aluminum alloy, J. Tianjin Univ. 28(3) (1995) 375-379.

[11] W. P. Chen, Y. F. Zhu and X. G. Zhang, Researching rare earth-aluminium alloy with it to make heat resistant cable which has high-strength and high conductivity, J. Kunming Metallurgy College 12(1, 2) (1996) 16-27.

[12] J. H. Yan, H. H. Chen, Effect of the heat treatment on the strengthen and electrical conductivity of 6063 aluminum alloy, Hot Working Techn. (2) (2004) 49-50.

[13] M. C. D. Andersen, Further results on the nucleation of precipitates in the Al-Zn-Mg system, Acta Metall. 47 (1966) 1009-1012.

[14] M. Murayama, K. Hono, Pre-precipitate clusters and precipitation processes in Al–Mg–Si alloys, Acta Mater. 47(5) (1999) 1537-1548.

DOI: 10.1016/s1359-6454(99)00033-6

[15] D. Pashley, M. Jacobs, J. Vietz, The basic processes affecting two-step ageing in an Al-Mg-Si alloy, Philosophical Magazine, 16(139) (1967) 51-76.

DOI: 10.1080/14786436708229257

[16] H. C. Liao, Y. N. Wu, K. Ding, Hardening response to rapid aging processes and precipitation in Al-7%Si-0. 3%Mg alloy. ICAA13: 13th International Conference on Aluminum Alloys, John Wiley & Sons, Inc., 2012, pp.1113-1118.

DOI: 10.1002/9781118495292.ch167

[17] H. C. Liao, Y. N. Wu, K. Ding, Hardening response and precipitation behavior of Al–7%Si–0. 3%Mg alloy in a pre-aging process. Mater. Sci. Eng. A, 560 (2013) 811-816.

DOI: 10.1016/j.msea.2012.10.041

[18] X.L. Li, J. H. Chen, C. H. Liu, J. N. Feng, S. H. Wang, Effect of T6 and T78 tempers on the microstructures and properties of Al-Mg-Si-Cu alloys, Acta Metall. Sinica, 49(2) (2013) 243-250.

DOI: 10.3724/sp.j.1037.2012.00509