JME_V2_N2_RP6 N. Muthukrishnan Journal on Mechanical Engineering 2249 - 0744 2 2 32 40 Hybrid MMC, Stir Casting, Turning, Surface Roughness, Power Consumed Aluminium metal matrix composites reinforced with SiC and B4C particles are a unique class of advanced engineered materials that have been developed to use in high strength , high wear resistant and tribological applications. The conventional techniques of producing these composites have some drawbacks. In this study, the aluminium hybrid composite is fabricated using stir casting method. 15 % by weight of SiC particles with an average size of 20 µm along with 5 % by weight of B4C particulates were reinforced in to the molten aluminium alloy of designation A356. The hardness, chemical composition and the micro-structure of the hybrid composite were investigated. Homogeneous distribution of SiC and B4C within Al hybrid composites is clear from the SEM images. Finally an attempt to study the machinability characteristics of the hybrid MMC in turning using Poly crystalline Diamond inserts (PCD) of Grade 1500.The experiment was conducted in a medium duty lathe of spindle power 2kW at various cutting speeds, feeds and depths of cut and parameters such as Power consumed, surface roughness were measured. The surface finish observed was found to be very close to the theoretical surface finish. The deviation in the value is concluded as the other parameters which influencing the machining. The optimum cutting conditions were obtained from the analysis of the results. By using this optimum cutting condition tool wear study was carried out. It is concluded that, tool wear mechanism is purely abrasive in nature. Surface finish is strongly dependent on cutting speed. Cutting speed is inversely proportional to surface roughness. Confirmation experiment also shows good agreement with the prediction value. February - April 2012 Copyright © 2012 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=1569