Tribological Behavior of Hybrid (LM25Al + SiC+ TiO2) Metal Matrix Composites

Abstract

In the present study the wear behavior of aluminium alloy LM25 reinforced with SiC particulate and further addition of TiO2 particulate fabricated by stir casting process is investigated. The wear resistance and frictional properties of hybrid metal matrix composite are studied by performing dry sliding wear test using a pin on disk wear tester. The experiments are conducted at a constant sliding velocity of 1.04m/s and sliding distance of 628m over a various load of 3,4,5kg for addition of particulate volume fraction of SiC 7.5% and increase in volume fraction by 2.5% & 5% TiO2. The results show that, the reinforcement of the metal matrix with SiC and TiO2 reduces the wear rate at room temperature. An attempt has also been made by keeping SiC percentage constant and increasing the TiO2 percentage it also proves wear rate decreases as the TiO2 content increases. The results also indicate that the wear of the test specimen increases with the increasing load and sliding distance. The coefficient of friction decreases with load and increasing volume content of reinforcement. The worn surfaces are examined by Scanning Electron Microscope to study the wear mechanism. At high speeds mechanical mixed layer (MML) and lubricating property of TiO2 exhibits between the composite pin and steel and thereby reducing the wear rate. The wear mechanism changes from severe abrasive wear to mild oxidative wear as the distance increases.