Proceedings of SerbiaTrib '13

Serbian TribologySocietySERBIATRIB ‘1313 th International Conference onTribologyKragujevac, Serbia, 15 – 17 May 2013Faculty of Engineeringin KragujevacINFLUENCE OF RICE HUSK ASH – SILICON CARBIDEWEIGHT RATIOS ON THE MECHANICAL BEHAVIOUR OFAL-MG-SI ALLOY MATRIX HYBRID COMPOSITESK. K. Alaneme 1 , T. M. Adewale 1,21 Department of Metallurgical and Materials Engineering Federal University of Technology, Akure, Nigeria,kkalaneme@gmail.com2 Faculty of Engineering and Physical Sciences, School of Materials, University of Manchester, Manchester, UnitedKingdomAbstract: The influence of rice husk ash (RHA) and silicon carbide (SiC) weight ratio on the mechanicalbehaviour of Al-Mg-Si alloy matrix hybrid composites was investigated. RHA and SiC mixed in weight ratios0:1, 1:3, 1:1, 3:1, and 1:0 were utilized to prepare 5, 7.5 and 10 wt% of the reinforcing phase with Al-Mg-Sialloy as matrix using two-step stir casting method. Density measurement, estimated percent porosity, tensileproperties, fracture toughness, and SEM examination were used to characterize the composites produced. Theresults show that the composites were of good casting quality as the estimated porosity values were less than2.5 % in all grades produced. For the three weight percent worked on, the tensile-, yield-, and specific strengthdecreases with increase in the weight proportion of RHA in the RHA-SiC reinforcement. However, the resultsshow that the composites with composition of 1:3 weight ratio RHA:SiC (25% RHA: 75% SiC) offerscomparable specific strength values with the single SiC reinforced Al composite grades. The strain to fractureswas invariant to the weight ratio of RHA/SiC for all weight percent but the composite compositions containingRHA had improved fracture toughness compared with the single SiC reinforced Al composite grades.Keywords: Aluminium matrix composites, rice husk ash, mechanical properties, scan electron microscopy,stir casting, silicon carbide.1. INTRODUCTIONAlternative sources of reinforcements that offer thepotential of producing Aluminium matrix composites(AMCs) at reduced cost while maintaining highperformance levels is attracting interests fromresearchers [1-2]. Compared to other engineeringmaterials, AMCs are noted for the rare combination ofproperties they offer such as high specific strength andstiffness, good wear and corrosion resistance, lowthermal coefficient of expansion, good hightemperature mechanical properties, and excellentthermal management potentials among others [3-5].Aluminium based matrices also have the advantagethat they are the cheapest among other competingmatrix materials (Copper, Titanium, Magnesium) formetal matrix composites (MMCs) development; andalso are amenable to processing using techniquesconventionally suited for the production of metals andalloys [6,7].The unique properties of AMCs are derivedfrom the material characteristics of both the matrixand the reinforcing phases [8]. The reinforcementsare responsible for the improved mechanical, wear,and high temperature properties of the AMCs [9-10]. Thus the type of reinforcement andreinforcement parameters such as size, volumefraction, distribution, shape, and orientation oftenaffect significantly the properties of AMCs [11].The use of cheaper source of reinforcements suchas industrial wastes (fly ash, red mud) [12-13] andagro wastes (rice husk ash, bamboo leaf ash,coconut shell ash) [14-15] for AMCs developmentis gaining popularity considering its advantage insolid waste recycling which has been a cause formajor concern over the years. Additional to theadvantages of low cost, availability in largequantities, and contributions to creation of a moreeco-friendly environment; is lower densities whichmost of the agro and industrial wastes possess in160 13 th International Conference on Tribology – Serbiatrib’13