Publication

Abstract : pThe influence of parameters like load, sliding speed, reinforcement content and their interactions on dry sliding wear rate of aluminium/fly ash/graphite hybrid metal matrix composites was investigated. The design of experiments (DOE) approach using Taguchi method was employed to analyze the wear behaviour of hybrid composites. A pinon-disc apparatus was used to conduct the dry sliding wear tests. Signal-to-noise ratio and analysis of variance (ANOVA) were used to investigate the influence of parameters on the wear rate, and correlation between them was established by a multiple linear regression model. The wear rate of the hybrid composites can be predicted by the multiple linear regression model. It was determined that load was the most significant parameter influencing the wear rate of the hybrid composites, followed by sliding speed and fly ash content. There was an increase in the wear rate of hybrid composites with increasing load, but the wear rate decreased with increase of sliding speed and fly ash content. The worn surfaces of the composite pins were analyzed by scanning electron microscopy to study the wear mechanisms. At high sliding speeds, mechanically mixed layer (MML) and a lubricating film of graphite were formed between the composite pin and the steel counterface and they reduced the chance of direct metallic contact, thereby lowered the wear rate. The wear mechanism changes from severe abrasive wear to mild oxidative wear at high sliding speeds. The incorporation of fly ash and graphite particles as reinforcements improved the tribological characteristics and caused a reduction in the wear loss of the hybrid composites. © EuroJournals Publishing, Inc. 2011./p