Foundry Metallurgy of Tungsten Carbide and Aluminium Silicate Particulate Reinforced LM6 Alloy Hybrid Composites

Thoguluva Raghavan Vijayaram


Hybrid composites are advanced composite materials in which a combination of two or more second phase particulates or fibers are reinforced in a base matrix. In this research paper, liquid metallurgical processing of a new hybrid composite material containing tungsten carbide particulate and aluminium silicate particulate combined at different weight fraction percentage is discussed. Manufacturing of such combined tungsten carbide particulate and aluminium silicate particulate reinforced aluminium-11.8% silicon alloy matrix composites by metal casting technology has some advantages of processing the composites by near net shape techniques. Turbulence generated by the liquid metallurgical vortex mixing technique is the easiest technique for processing these hybrid composites.  Aluminium-11.8% silicon alloy hybrid particulate, combined tungsten carbide and aluminium silicate reinforced composites is related to their higher strength, lightweight, hardness, higher temperature resistance and wear resistance than that of any conventional monolithic materials. In this experimental work, aluminum-silicon alloy composites containing tungsten carbide and aluminium silicate combined particulate combination of 2.5%, 5.0%, 7.5% and 10.0% on weight fraction basis are produced by using the liquid stirring method. The size of the tungsten carbide particulate
is 47.30 micron supplied by Aldrich, USA and the size of the aluminium
silicate particulate is equal to 157.10 micron supplied by Fluka, USA.
This paper discusses the vortex stirring process to produce these hybrid
composite castings. These are processed in the form of slab containing
2.5%, 5%, 7.5% and 10% weight fraction of the two combination of
particulate equally reinforced in LM6 alloy. A grey cast iron metallic mold
is used to pour the hybrid composite slurry mixture. Mechanical, electrical
and thermal properties are determined and all these aspects are discussed
in this paper. The microstructures of the processed hybrid composites are
studied at different magnifications and photomicrographs are captured to
identify the presence of the two different reinforced particulates and its
distribution uniformity. Fracture surface analysis has been performed to
study the failure mechanisms.

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