Prediction of Cooling Curves for Squeeze Cast Al/SiC p Composites Using Finite Element Analysis
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lloy, reinforced with ceramic particles such as SiC and Al2O3, is used in the automobile and aviation industries. Generally, particle-reinforced metal matrix composites (PRMMCs) are produced by several routes, i.e., powder metallurgy, liquid-state processing, and vapor deposition processes. Among these routes, liquid-state processing techniques have been employed successfully for the production of PRMMCs in the recent past.[1] Aluminum-based metal matrix composites offer a combination of higher specific stiffness, better elevated temperature properties, and improved wear resistance.[2] Squeeze casting is a liquidstate fabrication technique, and it is often used in the fabrication of Al/SiCp composites. In squeeze casting, solidification shrinkage is eliminated by the force feeding of liquid metal into voids. Therefore, castings produced by the squeeze casting process are free of shrinkage defects and exhibit excellent mechanical properties. The mechanical properties of composites P. GURUSAMY, formely Ph.D. Candidate with the Department of Mechanical Engineering, College of Engineering Guindy, Anna University, Sardar Patel Road, Chennai 600-025, India, is now Professor and Head with the Department of Mechanical Engineering, Jaya Engineering College, Thiruninravur, Chennai 602-024, India. Contact e-mail: guru8393@gmail. com S. BALASIVANANDHA PRABU, Associate Professor, is with the Department of Mechanical Engineering, College of Engineering Guindy, Anna University. R. PASKARAMOORTHY, Professor, is with the DST/ NRF Centre of Excellence in Strong Materials and School of Mechanical, Industrial and Aeronautical Engineering, University of the Witwatersrand, Private Bag 3, Johannesburg Wits 2050 South Africa. Manuscript submitted February 19, 2014. Article published online 21 January 2015 METALLURGICAL AND MATERIALS TRANSACTIONS A
fabricated using the squeeze casting technique depend on a number of parameters including the stirring action, squeeze pressure, melt temperature, and die temperature as they all affect the final microstructure in varying degrees.[3] It is therefore important that the process parameters be carefully selected in order for the composite to achieve optimum properties. In squeeze casting, a too low casting temperature causes inadequate fluidity to distribute the reinforcement particles into the melt; alternatively, a too high casting temperature can promote the settling of particles in the melt.[4] It is believed that the application of pressure for the period of solidification would be expected to affect the phase relationship in an alloy system.[5] Furthermore, particle agglomeration, inappropriate melt temperature, and stirring would affect the solidification rate.[6] These parameters must be maintained at their optimum levels during fabrication of the composites. Hanumanth and Irons[7] reported that the addition of ceramic particles into the melt increased the cooling rate, and thereby decreased the solidification time. This was attributed to the increase in effective thermal conductivity of the melt resultin
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