Friction characteristics of aluminium silicon carbide graphite hybrid composites

Hybrid aluminum metal matrix composites reinforced with silicon carbide (SiC) and graphite (Gr) are extensively used due to high strength and wear resistance. Friction behavior of such hybrid composites is quite vital in deciding the optimal combination of SiC and Gr. The sliding friction response of stir cast hybrid aluminum composites reinforced with equal weight fraction of SiC and Gr particulates of 2.5%, 5%, 7.5% and 10% reinforcement is investigated. The influence of % reinforcement, load, sliding speed and sliding distance on friction coefficient is studied using pin-on-disk equipment with tests based on design of experiments. Hardness of the composites decreases with increase in % reinforcement. Friction coefficient is influenced by sliding speed as well as load and its average value is around 0.269. But, % reinforcement and sliding distance do not affect the friction coefficient.

► LM25 metal matrix is reinforced, up to 10%, with equal weight fraction of silicon carbide and graphite particulates. ► Dry sliding friction tests are carried out using central composites design of statistical design of experiments. ► Friction behavior is influenced by load and sliding speed but, not affected by % reinforcement and sliding distance. ► The least friction coefficient is 0.264 and its average value is 0.269.