Effects of Melt Ultrasonic Treatment and Forming Processes on Thermo- Physical Properties of SiC_p/Mg and (SiC_p+Mg₂Si)/Mg Composites

Abstract:

The 10 vol% SiC_p/Mg composites were prepared by external addition and stirring-casting method, and the hybrid reinforced (10 vol% SiC_p+10 vol% Mg₂Si)/Mg composites were prepared by combining in-situ method. The effects of melt ultrasonic treatment (UT) and forming processes on the thermophysical properties of the two composites were studied. The results show that UT can effectively disperse SiC particles in molten magnesium and reduce the casting porosity, while squeeze casting can significantly reduce the porosity of the composites, which can also significantly improve the thermal conductivity. The thermal conductivity (λ) of 10 vol.% SiC_p/Mg composites squeeze casted after UT is 135.3 W/(mK) and the average coefficient of thermal expansion (CTE) is 19.95×10^-6 K^-1 at 293-373 K. Compared with gravity casting, the λ is increased by 17% and the CTE is reduced by 0.8%. The λ of (SiC_p+Mg₂Si)/Mg composite squeeze casted after UT is 132.4 W/(mK), and the CTE is 18.95×10^-6 K^-1, which is 27% lower than the CTE of pure magnesium.

• Periodical: Materials Science Forum (Volume 1035)
• Pages: 856-862
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1035.856
• Online since: June 2021
• Authors: Shu Sen Wu*, Tian Guo, Shu Lin Lü, Wei Guo, Lan Qing Xia
• Keywords: Coefficient of Thermal Expansion, Forming Process, Mg-Matrix Composites, Thermal Conductivity, Ultrasonic Treatment

References

[1] A.L. Geiger, D.P.H. Hasselman, K.Y. Donaldson. Effect of reinforcement particle size on the thermal conductivity of a particulate-silicon carbide-reinforce aluminum matrix composite. Journal of the American Ceramic Society, 12(1993): 420-423.

DOI: 10.1007/bf00609172

[2] K. Chu, C. Jia, W. Tian. Thermal conductivity of spark plasma sintering consolidated SiCp/Al composites containing pores: Numerical study and experimental valdation. Composites Part A: Applied Science and Manufacturing, 41(2010): 160-167.

DOI: 10.1016/j.compositesa.2009.10.001

[3] X. Zhou, T. Guo, S.S. Wu. Effects of Si content and Ca addition on the thermal conductivity of as-cast Mg-Si alloy. Materials, 11(2018): 2376-2388.

DOI: 10.3390/ma11122376

[4] T. Guo, S.S. Wu, X. Zhou, S.L. Lü. Effects of Si content and Ca modification on microstructure and thermal expansion property of Mg-Si alloys. Mater. Chem. and Phys. 253 (2020) 123260.

DOI: 10.1016/j.matchemphys.2020.123260

[5] Q. Gao, S.S. Wu, S.L. Lü, X.C. Xiong, R. Du, P. An. Effects of ultrasonic vibration treatment on particles distribution of TiB2 particles reinforced aluminum composites. Material Science & Engeering A, 680 (2017) 437–443.

DOI: 10.1016/j.msea.2016.10.103

[6] X.G Fang, S.L. Lü, L. Zhao, J. Wang, L.F. Liu, S.S. Wu. Microstructure and mechanical properties of a novel Mg-RE-Zn-Y alloy fabricated by rheo-squeeze casting. Materials and Design 94 (2016): 353-359.

DOI: 10.1016/j.matdes.2016.01.063

[7] L.G. Hou, R.Z. Wu, X.D. Wang. Microstructure, mechanical properties and thermal conductivity of the short carbon fiber reinforced magnesium matrix composites. J. of Alloys and Comp., 695(2017) 695: 2820-2826.

DOI: 10.1016/j.jallcom.2016.11.422

[8] A. Rudajevová, O. Padalka. Thermal expansion of pre-deformed, short fibre reinforced Mg-based composites. Composites Science and Technology, 2005, 65: 989–995.

DOI: 10.1016/j.compscitech.2004.11.001