Publication

Abstract : Functionally graded Al LM 25/10 wt{%} WC composite of dimension ∅out 100 × ∅in 60 × 100 mm was fabricated using centrifugal casting method. Mechanical and tribological properties of outer (1 mm), middle (11 mm) and inner (18 mm) layers from outer periphery of hollow cylindrical component were studied. Microstructural investigation revealed maximum distribution of reinforcements in outer layer, followed by middle and inner layer. Outer periphery had the highest hardness while outer zone displayed better tensile characteristics. Fractographs revealed brittle nature at outer layer due to high concentration of WC particles while a combined mode of ductile and brittle failure was observed at inner layer. Wear rate of outer layer increased linearly with increasing applied load, nonlinearly with increasing sliding velocity and sliding distance. Worn surface morphologies revealed fine and shallow grooves at outer layer ensuring mild material removal. Mild to severe wear transition was observed with increasing applied load. Mechanically mixed layer formation was observed with increasing velocity. This composite having enhanced mechanical and wear properties at outer zone is suitable for automotive applications such as pistons, liners, brake disks and bearings.