No abstract

Aluminium-based hybrid metal matrix nanocomposites (AA-HMNCs) have numerous applications due to their higher strength-to-weight ratio and good mechanical and tribological properties. However, the machinability aspect of these materials must be carefully explored before employing them in various engineering applications. The present study involves the fabrication of AA6061/2 wt.% SiC/x wt.% graphite (x= 1, 2, 3) hybrid nanocomposites and subsequently subjecting them to machinability investigation. All the hybrid nanocomposite samples are fabricated through ultrasonic assisted stir casting technique. The effect of machining parameters and graphite content of the sample on cutting force and surface roughness is discussed based on experimental data. Experiments are performed based on the central composite design of response surface methodology, and the corresponding output responses are recorded. ANOVA analysis revealed that the graphite content has the highest authority over surface roughness and cutting force. High cutting speeds accompanied by low feed and depth of cut have resulted in reduced cutting forces and better surface finish. Chip morphology studies have also subsequently indicated better machinability with increased graphite content.

Aluminium based hybrid nanocomposites can be employed in many applications owing to their desirable traits. Depending on the constituents of the hybrid metal matrix composites, they must be tested for their wear performance since there is a high chance that these materials will experience rapid wear. Determining the tribological behaviour of AA6061/ 2 wt. % SiCp nanocomposite and AA6061/2wt. % SiCp/2 wt. % graphite hybrid nanocomposite is the prime objective of this study. With AA6061 as the metal matrix and nano sized silicon carbide, graphite particles as primary and secondary reinforcements respectively, all the composite samples have been fabricated using ultrasonic assisted stir casting. Evaluation of the wear behaviour of the aforementioned materials is done using the two body abrasive wear tests conducted on a pin-on-disc apparatus. Wear coefficients and friction coefficients have been computed and were also analyzed with respect to various parameters. Additionally, wear mechanisms involved were deciphered and subsequently, wear maps have been developed for all the samples. The sample consisting 2 wt. % SiC and 2 wt. % graphite was found to have excellent wear resistance among all. Additionally, coefficient of friction was the lowest for the aforementioned sample itself.