Mechanical and tribological properties of functionally graded aluminium/zirconia metal matrix composite synthesized by centrifugal casting

Abstract

Abstract In the present study, functionally graded aluminium/zirconia metal matrix composite was fabricated using a liquid metallurgy route followed by centrifugal casting process and a hollow cylindrical component of dimensions 150 × 150 × 16 mm was obtained. Microstructural characteristics and mechanical properties along the radial direction were analysed to check the graded properties throughout the thickness of the casting. The tribological behaviour of the functionally graded composite was studied using a three body abrasion tester by varying the applied loads in the range of 33 – 80 N at two different rotating speeds of 100 and 200 rpm. The microstructural examination results showed that the outer surface of the composite has a particle rich zone due to centrifugal force as well as the density difference between alloy and reinforcement. Hardness was found to be higher at the outer surface and tensile strength was higher at the upper section of the composite due to the higher segregation of reinforcement particles. The abrasive wear test results revealed that the wear rate increases as applied load increases and decreases as rotating speed increases. The wear resistance was found to be maximum at the outer periphery compared to other surfaces under all conditions. Scanning electron microscopy analysis of worn surfaces revealed fine and shallow grooves on the external zone ensuring better wear resistance.