Wear Characteristics of Aluminium-Graphite Composites Produced by Stir Casting Technique

Abstract

Metal matrix composites (MMCs) are finding more applications due to their significantly improved properties such as high specific strength, high specific modulus, good damping capacity and good wear resistance compared to unreinforced alloys. In recent years, there has been an increasing interest in composites containing low density and low cost reinforcements. Graphite is one of the most suitable and low density reinforcement available for making light-weight and wear resistant parts for aircraft and automobile industry. At present the particulate reinforced aluminium matrix composites are gaining importance because of their low cost with advantages like isotropic properties and ease of fabrication. Use of aluminum as an antifriction material has been limited because of unfavorable wear. To improve wear resistance, it has been proposed to disperse graphite particles in to Al matrix. The present investigation is an attempt to produce particulate Al-graphite composites with superior wear resistance. Al-graphite composites with 1wt%, 3wt% and 5wt% graphite were prepared by stir casting technique by addition of graphite particles into the Al-melt treated with magnesium. Wear, hardness, and coefficient of friction studies of the composites were carried out. Graphite addition was found to increase wear resistance and the composite with 1wt% graphite had maximum hardness.

Keywords: Particulate composites, wear resistance, lubrication, stir casting