Effect of Compound Modification and Cooling Rate on Microstructure and Mechanical Properties of Al-25%Si Alloy

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The effect of phosphorus on primary silicon, phosphorus and mischmetal (Ce-50La) modification on primary and eutectic silicon and cooling rate on microstructure of Al-25%Si are investigated. The results show that, with the addition of phosphorus, the size of primary silicon decreases from 93.6μm to 24.75μm. The morphology of primary silicon changes from irregular to polygonal. When Al-25%Si is modified by phosphorus and mischmetal, primary and eutectic silicon all change effectively. Addition of mischmetal on the basis of phosphorus modification have no influence to primary silicon, but it can make morphology of eutectic silicon change from lamellar to short rod-like when the content of mischmetal reaches 0.5%. The cooling rate curves show the change of temperature in different height of wedge-shaped mould. When cooling rate increases, microstructure of Al-25%Si refines, the size of primary silicon decrease to 22.7μm. The results obtained from mechanical testing demonstrate that the addition of mischmetal and increasing of cooling rate increase hardness value of Al-25%Si alloy.

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Periodical:

Edited by:

Qing Liu, Jian-Feng Nie, Robert Sanders, Zhihong Jia and Lingfei Cao

Pages:

27-32

DOI:

10.4028/www.scientific.net/MSF.877.27

Citation:

H. T. Zhang et al., "Effect of Compound Modification and Cooling Rate on Microstructure and Mechanical Properties of Al-25%Si Alloy", Materials Science Forum, Vol. 877, pp. 27-32, 2017

Online since:

November 2016

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$38.00

* - Corresponding Author

[1] J. Chang, I. Moon, C. Choi, Refinement of Cast Microstructure of Hypereutectic Al-Si Alloys Through the Addition of Rare Earth Metals, J. Mater. Sci., 33(1998) 5015-5023.

[2] A. K. Dahle, K. Nogita, S. D. McDonald, C. Dinnis, L, Lu, Eutectic modification and microstructure development in Al–Si Alloys, Mater. Sci. Eng. A, 413–414(2005) 243–248.

DOI: 10.1016/j.msea.2005.09.055

[3] W. M. Wang, X. F. Bian, J. Y. Qin, S. I. Syliusarenko, The atomic-structure changes in Al-16Pct Si alloy above the liquidus, Metall. Mater. Trans. A, 31(2000) 2163-2168.

DOI: 10.1007/s11661-000-0134-y

[4] P. Kaur, D. K. Dwivedi, P. M. Pathak, Effects of electromagnetic stirring and rare earth compounds on the microstructure and mechanical properties of hypereutectic Al–Si alloys, Int. J. Adv. Manuf. Tech., 63(2012) 415-420.

DOI: 10.1007/s00170-012-3921-x

[5] H. K. Yi, D. Zhang, Morphologies of Si phase and La-rich phase in as-cast hypereutectic Al–Si–xLa alloys, Mater. Lett., 57(2003) 2523–2529.

DOI: 10.1016/s0167-577x(02)01305-8

[6] Q. Zhang, X. F. Liu, H. S. Dai, Re-formation of AlP compound in Al–Si melt, J. Alloy. Compd., 480(2009) 376–381.

DOI: 10.1016/j.jallcom.2009.02.080

[7] Q. L. Li, T. D. Xia, Y. F. Lan, W. J. Zhao, P. F. Li, Effect of rare earth cerium addition on the microstructure and tensile properties of hypereutectic Al–20%Si alloy, J. Alloy. Compd., 562(2013) 25-32.

DOI: 10.1016/j.jallcom.2013.02.016

[8] A. Q. Wang, L. J. Zhang, J. P. Xie, Effects of cerium and phosphorus on microstructures and properties of hypereutectic Al-21%Si alloy, J. Rare. Earth., 31(2013) 522–525.

DOI: 10.1016/s1002-0721(12)60313-5

[9] J. Y. Chang, G. H. Kim, I. G. Moon, C. S. Choi, Rare earth concentration in the primary Si crystal in rare earth added Al-21wt. %Si alloy, Scripta Mater., 39(1998) 307–314.

DOI: 10.1016/s1359-6462(98)00168-7

[10] N. Raghukiran, R. Kumar, Effect of scandium addition on the microstructure, mechanical and wear properties of the spray formed hypereutectic aluminum-silicon alloys, Mater. Sci. Eng. A, 641(2015) 138-147.

DOI: 10.1016/j.msea.2015.06.027

[11] C. L. Xu, Q. C. Jiang, Morphologies of primary silicon in hypereutectic Al–Si alloys with melt overheating temperature and cooling rate, Mater. Sci. Eng. A, 437(2006) 451-455.

DOI: 10.1016/j.msea.2006.07.088

[12] F. Vnuk, M. Sahoo, R. V. D. Merwe, R. W. Smith, The hardness of Al-Si eutectic alloys, J. Mater. Sci., 14(1979) 975-982.

DOI: 10.1007/bf00550730

[13] B. Tololi, A. Hellawell, Phase separation and undercooling in Al-Si eutectic alloy-the influence of freezing rate and temperature gradient, Acta Metall., 24(1976) 565-573.

DOI: 10.1016/0001-6160(76)90102-4

[14] H. F. Wang, F. Liu, Z. Chen, G. C. Yang, Y. H. Zhou, Analysis of non-equilibrium dendrite growth in a bulk undercooled alloy melt: Model and application, Acta Mater., 55(2007) 497-506.

DOI: 10.1016/j.actamat.2006.08.042

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