DEVELOPMENT AND TRIBOLOGICAL PROPERTIES OF PARTICULATE MMC DEVELOPED BY STIR CASTING PROCESS

Raghavendra N, V S Ramamurthy

Abstract: The present work concentrates on development of particulate metal matrix composite using Aluminum alloy (AL 7075) as the matrix material and alumina(Al2O3), Silicon Carbide (SiC) and Hybrid (Al2O3+SiC) as Reinforcement.Al2O3 is reinforced in the weight fraction of3%, 6%, 9% and 12% with the particle size varying between 50 microns to 150 microns. SiC in the weight fraction of 3%, 6%, 9% and 12% & Al2O3+SiC in the weight fraction of 3%+3%, 6%+3%, 9%+3% and 12%+3%. The aluminum alloy was melted at 700°C in an electrical heating furnace for 20 minutes and the reinforcement is heated separately at 350° C was added in the form of powder. The mixture was stirred for 5 minutes at the temperature of 650°C, then poured in to the sand mold. Optical micro graph of the developed composite was obtained to demonstrate the distribution of the reinforcement in the matrix. The hardness tests was carried out to determine the effect of reinforcement on the hardness of the composites. It is observed that the hardness of the composite increases with the increase in weight fraction of the reinforcement. The wear test carried out at various speed, load and sliding distance which indicates improvement in the mechanical properties of the composites. The wear resistance of the composite was found to reduce with the increase in the weight fraction of the reinforcement. The wear resistance was found to decrease with increase in speed, but it increases with the increase in load and sliding distance for all specimens. The coefficient of friction was found to decrease with the increase in weight fraction of the reinforcement. The noise during running the test was reduced in case of Hybrid composite as compared to composite with either alumina or silicon carbide as reinforcement. The investigation carried out will lead to development of the composite system with high strength, improved wear resistant, light weight for automobile parts like disc brake, piston, cylinder liner, drive shaft etc.

Keywords: Wear, Al7075/Al2O3, SiC, Hybrid, Stir casting, Weight fraction.

DOI: https://doi.org/10.15623/ijret.2016.0525015