Effect of Modification and Cooling Rate on Primary Grain in Al-Cu Alloy

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This paper presents a study of the effect of the modification and cooling rate on the grain count α(Al) in the Al-5Cu alloy. Research was performed on castings with walls thickness between 3 mm and 25 mm. Cooling curves were recorded to determine the cooling rate and the degree of undercooling at the beginning of solidification. It has been shown that cooling rate increases exponentially as the wall thickness of casting decreases. Moreover it has been demonstrated that the cooling rate of castings changes within a wide range (21°C/s - 1°C/s) when the wall thickness changes from 3 up to 25 mm. Metallographic examinations revealed primary grains (primary α(Al) grains). The paper show that the relationship between the grain count and the degree of undercooling (for non-modified and modified alloys) can be represented by the equation N = Nv = np·exp(-b/ΔTα), based on the Weibull's distribution of the size of nucleation sites.

[1] Murty, B.S., Kori, S.A. & Chakraborty, M. (2002). Grain refinement of aluminium and its alloys by heterogeneous nucleation and alloying. International Materials Reviews. 47(13), 3-29.

[2] Spittle, J.A. (2006). Grain refinement in shape casting of aluminium alloys. International Journal of Cast Metals Research. 19(4), 210-222.

[3] Xiaowu, H., Fanrong, A. & Hong, Y. (2012). Influence of pouring temperature and cooling rate on microstructure and mechanical properties of casting Al-Si-Cu aluminum alloy. Acta Metallurgica. 25(4), 272-278.

[4] Grosselle, F., Timelli, G., Bonollo, F., Tiziani, A. & Della Corte, E. (2009). Correlation between microstructure and mechanical properties of Al-Si cast alloy. Metallurgia Italiana. 101(6), 25-32.

[5] Easton, M.A. & StJohn, D.H. (2000). The Effect of Grain Refinement on the Formation of Casting Defects in Alloy 356 Castings. International Journal of Cast Metals Research. 12, 393-408.

[6] Lin, S., Aliravci, C. & Pekguleryuz, M. (2007). Hot-Tear susceptibility of aluminum wrought alloys and the effect of grain refining. Metallurgical and Materials Transactions A. 38, 1056-1068.

[7] Górny, M. & Sikora, G. (2013). The Influence of Cooling Rate on the Number of Primary Grains in Al-5Cu Alloy. Archives of Foundry Engineering. 13(3), 25-30.

[8] Rys, J. (1995). Stereology of Materials. Kraków: Fotobit.

[9] Ohser, J., Lorz, U. (1994). Quantitative gefuegeanalyse. Leipzig-Stuttgart: DVG.

[10] Fraś, E., Wiencek, K., Górny, M., Lopez, H. & Olejnik, E. (2013). Equiaxed grain count in aluminum alloy castings: Theoretical background and experimental verification. Metallurgical and Materials Transactions A. 44(13), 5788-5795.

[11] Quested, T.E. & Greer, A.L. (2005). Grain refinement of Al alloys: Mechanisms determining as-cast grain size in directional solidification. Acta Materialia. 53, 4643–4653.

[12] Quested, T.E., Greer, A.L. (2004). The effect of the size distribution of inoculant particles on as-cast grain size in aluminium alloys. Acta Materialia. 52, 3859-3868.

Archives of Foundry Engineering

The Journal of Polish Academy of Sciences

Journal Information

CiteScore 2016: 0.42

SCImago Journal Rank (SJR) 2016: 0.192
Source Normalized Impact per Paper (SNIP) 2016: 0.316


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