Tribological behaviour and wear fashion of processed AA6061/ZrO2 composite

Abstract

Purpose This study aims to develop a less weight high wear resistant material to fabricate brake components especially in automotive sector. Design/methodology/approach Effort was initiated to design and develop aluminium metal matrix composite by combining aluminium alloy AA6061 and zirconium oxide (ZrO2) with the help of stir casting coupled with squeeze casting unit. Morphology analysis of advanced composite has been carried out by optical microscopy and scanning electron microscopy (SEM). The hardness of composites having different compositions was tested using Vickers micro hardness tester. The tribological property of the developed three specimens having different composition has been tested using pin-on-disc wear test equipment under dry sliding conditions. To obtain better understanding of wear mechanism, SEM image of worn-out surface was captured and analysed. SEM images and the corresponding Energy-dispersive X-ray spectroscopy (EDX) on the wear surface were carried out. Findings The optical and SEM images evidenced the existence of ZrO2 particles along the metal matrix composite. Porosity values shows that the porosity level is acceptable as it falls below 7 per cent. Also, the finding proves that increase in the percentage of reinforcement particle instigates agglomeration on the AA6061 composites. Hardness test demonstrated that the inclusion of hard ZrO2 particles leads to substantial improvement in hardness and the hardness value started deteriorating when the composition reaches 15 per cent. The wear test results substantiated the enhancement of tribological property due to the inclusion of distinct ZrO2 particles. Also, despite of addition of reinforcements, the wear rate increased when the load increases. SEM images proved that AA6061/ZrO2-5 per cent composite fashioned steady-state mild and smooth wear. EDX spectrum analysis revealed the existence of ZrO2 particles along with wear debris, which caused wear of 685 µm in AA6061/ZrO2-15 per cent composite. Originality/value The developed material possesses low wear rate which is the unique property of composite and frictional force which is directly proportional to load but the coefficient of friction remains apparently constant. As a whole, investigations on developed composites introduce a new material which is suitable for manufacturing of brake components for automobile industry.