Investigating the effect of reinforcing particulates on the weight loss and worn surface of compocast AMCs

Abstract

This paper aims to investigate the abrasive wear behavior of the sol-gel coated B4C particulate reinforced aluminum metal matrix composite. Sliding wear is related to asperity-to-asperity contact of two counter surfaces, which are in relative motion against each other. The effective wear from the specimen surface is due to the combined effect of a number of factors. An increase in the applied load leads to increase in penetration of hard asperities of the counter surface to the softer pin surface, increase in micro cracking tendency of the subsurface and also increase in the deformation and fracture of asperities of the softer surface. In general, composites offer superior wear resistance as compared to the alloy irrespective of applied load and B4C particles volume fraction. This is primarily due to the presence of the hard dispersoid which protects the matrix from severe contact with the counter surfaces, and thus results in less wear, lower coefficient friction and temperature rise in composite as compared to that in the alloy. The worn surfaces of all specimens were covered with grooves parallel to the sliding direction and some plastic deformations. These grooves are typical features associated with abrasive wear, in which hard asperities on the steel counter face or hard particles between the pin and disc, plough or cut into the pin cause wear by the removal of the material. Plastic deformation, material smearing, cavities and craters imply adhesive wear. K e y w o r d s: dry sliding, adhesive, mechanically mixed layer