Experimental Investigation of Peripheral Milling of Functionally Gradient Al-SiC Metal Matrix Composite

Abstract

Metal matrix composites (MMCs) offer superior mechanical and thermal properties, but the poor machinability of these composites hinders their wide application [1,2]. The machinability of the MMCs are found to be largely dependent on the particle size and volume fraction of the reinforcements used. Experimental investigation on process modeling of MMCs by milling is undertaken. In this study, peripheral milling of functionally gradient concentration of SiC in aluminum matrix using carbide tools is discussed. The process conditions were varied namely, the feed was varied from 0.1 mm/rev to 0.3 mm/rev and the speed from 1000 to 5000 rpm with a constant depth of cut of 1.27mm. The variation of cutting force, surface roughness and cut surface morphology with varying SiC particle distribution, feed and speed are reported. The interaction of the cutting edge with hard SiC particles in Al matrix was also studied using the scanning electron microscopy (SEM). The cutting force and surface roughness were found to increase with increasing volume fraction of SiC particles. Preliminary observation showed that the SiC particles were either removed from the matrix by debonding due to mismatch of thermal coefficients or were fractured by the action of the cutting edge or were pushed into the aluminum matrix.