Numerical Study on the Impact of Cooling Rate on the Solidification of Al-Bi Hypermonotectic Alloys

Abstract:

A numerical model describing the liquid-liquid phase transformation of the nucleation, the diffusional growth, Ostwald coarsening and macro-transport phenomena was established based on Euler-Euler method. The microstructure development of Al-Bi alloys in different solidification rate has been simulated by coupling the calculated temperature and velocity fields with the kinetic equation which controls the microstructure evolution. The results showed that average diameter difference of L₂ phase droplets between top and bottom of samples in low cooling rate increased by 151 % than in high cooling speed and the maximum volume fraction of the droplets at the bottom of the sample in low cooling rate much higher than in high cooling rate. Analysis that the bigger cooling rate can shorten the action time which caused by gravity settling and collisions coagulation of the droplets, and then improves the macrosegregation of solidification structure in favor of uniform distribution of the solidification structure.

• Periodical: Key Engineering Materials (Volume 727)
• Pages: 111-116
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.727.111
• Online since: January 2017
• Authors: Zhi Qiang Kang, Xue Yang, Guo Hui Feng, Lin Zhang
• Keywords: Al-Bi Hypermonotectic, Cooling Rate, Numerical Analysis, Solidification Microstructure

References

[1] D. Mirković, J Gröbner and F.R. Schmid: Acta Materialia, Vol. 56(2008) No. 18, p.5214.

[2] N. Wang, B. Wei: Materials Science and Engineering: A, Vol. 345(2003) No. 1-2, p.145.

[3] L.H. Li, J.Z. Zhao: Acta Metallurgica Sinica, Vol. 46(2010)No. 6, p.695(In Chinese).

[4] C. Shu, Z.J. Zhao, H. X, Jiang, et al: Acta Metall, Vol. 28(2015)No. 3, p.316.

[5] L.H. Li, J.Z. Zhao: Acta Metallurgica Sinica, Vol. 47(2011)No. 1, p.81 (In Chinese).

[6] Z.Q. Kang E.G. Wang,L. Zhang, et al: Joural of Northeastern Univercity (Natural Science)Vol. 31 (2010)No. 9, p.1262(In Chinese).

[7] Z.Q. Kang E.G. Wang,L. Zhang, et al: Joural of Functional Materials, Vol 41(2010) No. 9, p.1536 (In Chinese).

[8] P. Thévoz, J. L. Desbiolles and M. Rappaz: Materials Science and Engineering R, Vol 20A (1989) No. 2, p.311.

[9] J.Z. Zhao: Zn-Pb Monotectic Alloy Liquid Separation Mechanism and the Solidification Behaviour (Ph.D., Harbin Institute of Technology, China, 1994) (In Chinese).

[10] L. Ratke, S. Diefenbac: Materials Science and Engineering R, Vol. 15(1995)No. 7-8, p.263.

[11] Z.Z. Han,J. Wang: FLUENT - Fluid Simulation Calculating Examples and Engineering Application(Beijing institute of technology press, China 2004 ).

[12] R.J. Wang, K. Zhang: Fluent Software Technology Foundation and Application Example (Tsinghua University Press, China 2007).

[13] J .Z. Zhao, L. Ratke: Modelling and Simulation in Materials Science and Engineering, Vol. 6 (1998) No. 2, p.123.