Effect of Sr and Ni Addition on Microstructure, Tensile Behavior and Electrical Conductivity of Squeeze Cast Al-6Si-3Cu Al Alloy

Abstract:

Mechanical strengths and electrical conductivity are the very important engineering properties of lightweight aluminum (Al) alloys used in automobiles, especially for battery-powered electric vehicles (BEV). However, the main issue is that the mechanical properties and the electrical conductivity of Al alloys are mutually exclusive. This study aims to simultaneously improve both the tensile properties and the electrical conductivity of the squeeze as-cast Al-6wt% Si-3wt% Cu by modifying its microstructure with the addition of nickel (Ni) and strontium (Sr). In comparison to those of the alloy free of Sr and Ni, the additions of 0.03 wt.% Sr and 0.5 wt.% Ni in the Al-6Si-3Cu alloy significantly improved the ultimate tensile strength, yield strength and electrical conductivity. This was because the addition of Ni element, as a transition element, collaborated with Cu to form fine intermetallic Al-Cu-Ni phases for dispersion strengthening. Also, the modification of the Si morphology from micron needles to nanoparticles by the Sr addition enhanced both the strengths and electrical conductivity of the developed alloy.

• Periodical: Key Engineering Materials (Volume 921)
• Pages: 3-14
• DOI: https://doi.org/10.4028/p-045ngi
• Online since: May 2022
• Authors: Yu Xian Li, Yin Tian Fu, Anita Hu, Xueyuan Nie, Henry Hu*
• Keywords: Aluminum Alloy, Electrical Conductivity, Nickle, Squeeze Cast, Strontium

References

[1] Y. Liu, P. Han, A.M.A. Bazzi, A comparison of rotor bar material of squirrel-cage induction machines for efficiency enhancement purposes, EPE'15 ECCE-Europe, pp.1-7.

DOI: 10.1109/epe.2015.7311778

[2] T. Shi, F. Zhao, H. Hao, Z. Liu, Costs, Benefits and Range: Application of Lightweight Technology in Electric Vehicles, SAE Technical Paper 2019-01-0724, (2019).

DOI: 10.4271/2019-01-0724

[3] R.W. Cahn, P. Haasen, E.J. Kramer, Material science and technology, vol 8/9. Wiley, New York, (2005).

[4] J.A. Garcı́a-Hinojosa, C.R. Gonzalez, G.M. Gonzalez, Y. Houbaert, Structure and properties of Al–7Si–Ni and Al–7Si–Cu cast alloys nonmodified and modified with Sr, J. Mater. Process. Technol. 143 (2003) 306-310.

DOI: 10.1016/s0924-0136(03)00479-5

[5] G. Rajaram, S. Kumaran, T.S. Rao, Effect of graphite and transition elements (Cu, Ni) on high temperature tensile behaviour of Al–Si Alloys, Mater. Chem. Phys.128 (2011) 62-69.

DOI: 10.1016/j.matchemphys.2011.02.069

[6] Z. Asghar, G. Requena, H.P. Degischer, P. Cloetens, Three-dimensional study of Ni aluminides in an AlSi12 alloy by means of light optical and synchrotron microtomography, Acta Mater. 57 (2009) 4125-4132.

DOI: 10.1016/j.actamat.2009.05.010

[7] Z. Asghar, G. Requena, F. Kubel, The role of Ni and Fe aluminides on the elevated temperature strength of an AlSi12 alloy, Mater. Sci. Eng. 527 (2010) 5691-5698.

DOI: 10.1016/j.msea.2010.05.033

[8] J.E. Gruzleski, B.M. Closset, The treatment of liquid aluminum-silicon alloys. Amer Foundry Society, California, (1990).

[9] A.K. Dahle, K. Nogita, S.D. McDonald, J.W. Zindel, L.M. Hogan, Eutectic nucleation and growth in hypoeutectic Al-Si alloys at different strontium levels, Metall Mater Trans A Phys Metall Mater Sci. 32 (2001) 949-960.

DOI: 10.1007/s11661-001-0352-y

[10] Y.H. Cho, H.C. Lee, K.H. Oh, A.K. Dahle, Effect of strontium and phosphorus on eutectic Al-Si nucleation and formation of β-Al 5 FeSi in hypoeutectic Al-Si foundry alloys. Metall Mater Trans A Phys Metall Mater Sci. 39 (2008) 2435-2448.

DOI: 10.1007/s11661-008-9580-8

[11] A.K. Dahle, K. Nogita, S.D. McDonald, C. Dinnis, L. Lu, Eutectic modification and microstructure development in Al–Si Alloys. Mater. Sci. Eng, 413 (2005) 243-248.

DOI: 10.1016/j.msea.2005.09.055

[12] M.H. Mulazimoglu, R.A.L. Drew, J.E. Gruzleski, The effect of strontium on the electrical resistivity and conductivity of aluminum-silicon alloys. Metall Mater Trans A, 18 (1991) 941-947.

DOI: 10.1007/bf02668542

[13] S.Z. Lu, A. Hellawell, The mechanism of silicon modification in aluminum-silicon alloys: impurity induced twinning. Metall Mater Trans A. 18 (1987) 1721-1733.

DOI: 10.1007/bf02646204

[14] Y. Li, Y. Yang, Y. Wu, L Wang, X, Liu, Quantitative comparison of three Ni-containing phases to the elevated-temperature properties of Al–Si piston alloys. Mater. Sci. Eng 527 (2010) 7132-7137.

DOI: 10.1016/j.msea.2010.07.073

[15] J. Campbell, Complete casting handbook: metal casting processes, metallurgy, techniques and design. Butterworth-Heinemann, London, (2015).

[16] J. Campbell, M. Tiryakioğlu, Review of effect of P and Sr on modification and porosity development in Al–Si alloys. Mater. Sci. Technol, 26 (2010) 262-268.

DOI: 10.1179/174328409x425227

[17] J. Zhou, L. Ren, X. Geng, L. Fang, H. Hu, As-cast magnesium AM60-based hybrid nanocomposite containing alumina fibres and nanoparticles: Microstructure and tensile behavior, Mater. Sci. Eng. A, 740 (2019) 305-314.

DOI: 10.1016/j.msea.2017.10.070

[18] A. Russell, L.L. Kok, Structure-property relations in nonferrous metals. John Wiley & Sons, Canada (2005).

[19] O.A. Kaibyshev Superplasticity of alloys, intermetallides and ceramics. Springer Science & Business Media, Basingstoke, (2012).

[20] F.C. Campbell, Elements of metallurgy and engineering alloys. ASM International, Ohio, (2008).

[21] B. Larson, Toughness, NDT Education Resource Center, Iowa, (2001).

[22] M.H. Mulazimoglu, R.A.L. Drew, J.E. Gruzleski, The electrical conductivity of cast Al− Si alloys in the range 2 to 12.6 wt pct silicon. Metall. Trans A, 20 (1989) 383-389.

DOI: 10.1007/bf02653917

[23] S.S. Shin, M.Y. Kim, G.Y. Yeom, The Effect of Sr Addition and Holding Time on Mechanical Property and Electrical Conductivity of Al-10.5% Si-2% Cu Secondary Die-casting Alloys. J. Korea foundry soc, 30 (2010) 205-209.