Influence of cooling mediums on mechanical and tribological characteristics of Al/Cu-based composites reinforced with chromium particles

The intensity of radial heat flux during quenching affects the microstructural features of materials. The interface strength is also affected by the radial heat flux in the case of metal matrix composites (MMCs). Thus, the mechanical and tribological behaviour of MMCs may vary with the quenching medium. The present investigation deals with the effect of the quenching medium on the mechanical and tribological behaviour of chromium (Cr) particles reinforced Al/Cu dual matrix composites. Normal load (viz. 20, 40 and 60 N) and weight percentage of Cr reinforcement (viz. 1, 2, 3, 5, 8 and 10 wt. %) were also varied. The powder metallurgy route was followed for the fabrication of composites. The sintered composites were normalised and quenched in oil and water. The results revealed that water-quenched composites exhibited the highest hardness and compressive strength and the lowest wear. The highest compressive strength was approximately 48 MPa for 3 wt. % Cr reinforced water-quenched composites. The coefficient of friction decreased with an increase in Cr content, whereas it was very difficult to generalise the wear behaviour with respect to Cr content. The fractured and worn surfaces were analysed under a scanning electron microscope to know the fracture characteristics and dominant wear mechanisms, respectively.