Study of Dry Sliding Wear Characteristics of Boron Carbide and Ilmenite Mineral Reinforced AMCs

Abstract

Dry sliding wear behaviour of stir-cast aluminium matrix composites (AMCs) containing LM13 alloy as matrix and synthetic ceramic particles and mineral particles as reinforcements was investigated at room temperature as well as at high temperature operating conditions. Particles were reinforced in three different ways viz. (a) only synthetic ceramic particles (boron carbide; B4C), (b) only mineral particles (ilmenite; FeTiO3), and (c) combination of synthetic and mineral particles in various mixing proportions. Composites processed using these reinforcements were designated as BR composites, IR composites, and BI composites respectively. Particle size for both types of reinforcements was categorized into two classes viz. (a) fine and (b) coarse whose range was 20 32 and#956;m and 106 125 and#956;m respectively. For each particle size, the weight percentage of reinforcement was varied from 0 15 wt.%, with a step size of 5 wt.%. For combination of synthetic and mineral particles, reinforcements with same particle size were mixed in three different weight proportions of 1:3, 1:1, and 3:1. For processing of AMCs, the base alloy (LM13) was melted in the stir casting set-up using an electric furnace maintained at 700 °C. Ceramic particles to be reinforced were pre-heated in another electric furnace maintained at 450 °C to eliminate moisture or volatile matter (if present) from the particles. Before addition of pre-heated particles, a vortex was developed in the molten mass by using a three-blade graphite stirrer. Uniform stirring at 625 rpm was maintained for 10 min. Thereafter, the required amount of particles (wt.%) was added to the molten mass by reducing the stirring speed to 250 rpm. Again, stirrer speed was maintained at 625 rpm for 10 min. Finally, molten mass was poured in a cast iron mould to allow cooling till room temperature. SEM images of ball milled reinforced particles were used to obtain the average particle size whereas EDS was used to obtain the elemental composition of reinforcements.