Experimental and Numerical Simulation of Surface Segregation in Two-Phase Zone Continuous Casting Cu–Sn Alloy

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Abstract:

Surface segregation exists in two-phase zone continuous casting (TZCC) alloy with wide solid–liquid two phase zone. The surface segregation formation cannot be explained by the traditional solidification theories. ProCAST software was used to simulate the TZCC process for preparing the Cu–4.7 wt%Sn alloy with wide solid–liquid two phase zone. The Sn solute distribution in TZCC Cu–4.7 wt%Sn alloy was investigated, and the surface segregation mechanism of TZCC Cu–4.7 wt%Sn alloy was analyzed. The results showed that numerical simulation results were agreed with that of experimental. TZCC Cu–4.7 wt%Sn alloy in the center firstly started to solidify and resulted in “Λ” shape inclined solid/liquid (S/L) interface near the mold. Therefore, a narrow gap between the wall of the two-phase zone mold and the S/L interface formed. On the one hand, while Cu–4.7 wt%Sn alloy solidified along the opposite continuous casting direction, the solute redistribution between the solid and the liquid occurred, which lead to Sn solute decreased in solid and enriched in front of S/L interface. Because the narrow gap lies in front of inclined S/L interface near the two-phase zone mold, Sn solute enriches in liquid of the narrow gap. On the other hand, during the TZCC process, solid grains nucleate on the wall of the two-phase zone mold, while the melt feeds into the two-phase zone mold which the temperature is in the two-phase zone of the Cu–4.7 wt%Sn alloy. The solute redistribution also occurs while the solid grains grow, thus lead to Sn content increases in front of S/L interface near the wall of the two-phase zone mold. The enriched Sn solute is too late to diffuse, and will quickly flows into the narrow gap, resulting in further increasing of Sn content in the narrow gap. The liquid with enriched Sn solute in the narrow gap will become the surface layer after solidification, which lead to surface segregation layer during the TZCC Cu–4.7 wt%Sn alloy.

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610-617

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March 2016

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[1] X.Y. Liu, D. Tham, D. Yates, C.J. McMahon Jr., Evidence for the intergranular segregation of tin to grain boundaries of a Cu–Sn alloy and its consequences for dynamic embrittlement, Mater. Sci. Eng. A. 458(2007) 123–125.

DOI: 10.1016/j.msea.2006.12.103

Google Scholar

[2] M. Yamaguchi, M. Shiga, H. Kaburaki, Grain boundary decohesion by impurity segregation in a nickel-sulfur system, Science. 307(2005) 393–397.

DOI: 10.1126/science.1104624

Google Scholar

[3] M. Herbig, M. Kuzmina, C. Haase, R.K.W. Marceau, I. Gutierrez-Urrutia, D. Haley, D.A. Molodov, P. Choi, D. Raabe, Grain boundary segregation in Fe–Mn–C twinning-induced plasticity steels studied by correlative electron backscatter diffraction and atomprobe tomography, Acta Mater. 83(2015).

DOI: 10.1016/j.actamat.2014.09.041

Google Scholar

[4] S. Minakawa, I.V. Samarasekera, F. Weinberg, Inverse Segregation, Metall. Trans. B. 16(1985) 595–604.

DOI: 10.1007/bf02654858

Google Scholar

[5] S.G. Lee, G.R. Patel, A.M. Gokhale, Inverse surface macro-segregation in high-pressure die-cast AM60 magnesium alloy and its effects on fatigue behavior, Scripta Mater. 52(2005) 1063–1068.

DOI: 10.1016/j.scriptamat.2005.01.007

Google Scholar

[6] R. Mehrabian, M.A. Keane, M.C. Flemings, Experiments on macrosegregation and freckle formation, Metall. Trans. 1(1970) 3238–3241.

DOI: 10.1007/bf03038445

Google Scholar

[7] A.K. Sample, A. Hellawell, The mechanisms of formation and prevention of channel segregation during alloy solidification, Metall. Trans. A. 15(1984) 2163–2173.

DOI: 10.1007/bf02647099

Google Scholar

[8] S.D. Felicelli, J.C. Heinrich, D.R. Poirier, Simulation of freckles during vertical solidification of binary alloys, Metall. Trans. B. 22(1991) 847–857.

DOI: 10.1007/bf02651162

Google Scholar

[9] M.C. Flemings, Solidification Processing, McGraw-Hill, New York. (1974).

Google Scholar

[10] X. Liu, J. Luo, X. Wang, Surface quality, microstructure and mechanical properties of Cu−Sn alloy plate prepared by two-phase zone continuous casting, Trans. Nonferrous Met. Soc. China. 25(2015) 1901−(1910).

DOI: 10.1016/s1003-6326(15)63797-9

Google Scholar

[11] W. Li, H. Shen, B. Liu, Numerical simulation of macrosegregation in steel ingots using a two-phase model, Int. J. Miner. Metall. Mater. 19(2012) 787–794.

DOI: 10.1007/s12613-012-0629-8

Google Scholar

[12] C. Stelian, T. Duffar, I. Nicoara, Comparison between numerical simulation and experimental measurement of solute segregation during directional solidification, J. Cryst. Growth. 255(2003) 40–51.

DOI: 10.1016/s0022-0248(03)01199-0

Google Scholar

[13] D.G. Eskin, J.J. Zuidema Jr., V.I. Savran, L. Katgerman, Structure formation and macrosegregation under different process conditions during DC casting, Mater. Sci. Eng. A. 384 (2004) 232-244.

DOI: 10.1016/j.msea.2004.05.066

Google Scholar

[14] T. Fujii, D.R. Poirier, M.C. Flemings, Macrosegregation in a multi-component low alloy steel, Metall. Trans. B. 10(1979) 331-339.

DOI: 10.1007/bf02652503

Google Scholar

[15] X. Liu, J. Luo, X. Wang, L. Wang, J. Xie, Columnar grains-covered small grains Cu–Sn alloy prepared by two-phase zone continuous casting, Prog. Nat. Sci. 23(2013) 94–101.

DOI: 10.1016/j.pnsc.2013.01.014

Google Scholar

[16] Y. Xia, F. Wang, J. Wang, G. Li, Simulation of the continuous casting process in a mold of free-cutting steel 38MnVS based on a MiLE method, Int. J. Miner. Metall. Mater. 18(2011) 562–569.

DOI: 10.1007/s12613-011-0478-x

Google Scholar