Tribological characteristics of innovative Al6061–carbon fiber rod metal matrix composites

Abstract

Rods made of continuous carbon fibers are being extensively used as structural materials in light weight micro-air vehicles owing to their excellent specific modulus and strength. Further, they possess excellent tribological characteristics – low friction and wear coupled with high conductivity making them an ideal reinforcement in developing light weight, high strength aluminum based metal matrix composites. In the last three decades, researchers have focused mainly on the study of mechanical and tribological behavior of discontinuous carbon fiber reinforced metal matrix composites. However, no information is available regarding the tribological behavior of carbon fibers rod reinforced metal matrix composites, although it is interesting and will result in expanding the applications of metal matrix composites (MMC) where tribological failures are expected.In the light of the above, the present work focuses on development of innovative Al6061–carbon fiber rods composites by casting route and assessing their tribological characteristics. Carbon fiber rods of 4mm and 6mm diameters were surface sensitized to achieve electro less nickel coating. Copper plating on the electro less nickel coated carbon fiber rods were carried out. The copper plated carbon fiber rods were arranged in cylindrical array in the metallic mold to which molten Al6061 alloy after degassing was poured at a temperature of 700°C. The developed innovative composites were subjected to density tests, microstructure studies, hardness, friction and wear tests. A pin on disk configuration was used with hardened steel as the counter face. Load was varied from 20N to 60N while the sliding velocity was varied between 0.12m/s and 0.62m/s. Scanning electron microscopy (SEM) studies on worn surfaces and wear debris have been carried out to validate the wear mechanism. The developed innovative composites (11Vol.% & 25Vol.%) have exhibited lower coefficient of friction and wear rates when compared with matrix alloy.