Reciprocal dry sliding wear of SiCp/Al–7Si-0.3 Mg functionally graded composites: Influence of T6 treatment and process parameters

Abstract

The present work discusses an attempt to enhance the mechanical and reciprocal wear response of Al–7Si-0.3 Mg alloy through the addition of 10 wt% SiC as reinforcement and subsequent T6 treatment. Friction and reciprocating wear behavior of both untreated and heat treated functionally graded composites were studied under unlubricated sliding conditions, employing a linear reciprocating pin-on-plate system over a range of applied load (10–50 N) and sliding distance (500–2500 m). Microstructural studies revealed reinforcement particle gradation across the cast thickness for untreated composite with minimal particle clusters whereas, heat treated composite showed the presence of fine α-spheroidised eutectic silicon. The outer layer of heat-treated composite when compared to outer layer of as-cast composite, revealed an 18 % increase in hardness, 70 % increase in tensile strength and 8 % decrease in wear rate. Wear studies confirmed a linear dependency between wear rate and applied load whereas, coefficient of friction displayed fluctuating trends. Wear mechanisms were identified, with worn morphology and EDS analyses in agreement with the results obtained and was correlated with the observed metallurgy and mechanical properties. These composites were identified as potential candidates for applications such as brake drums/rotors, cylinder liners, cylinder blocks and pistons.