Dry sliding wear studies of aluminum matrix hybrid composites

In the present work, hybrid composites are fabricated with self-lubricating characteristics to make them as resource-efficient materials. AA6061-10 wt. % B4C-MoS2 hybrid composites reinforced with 2.5, 5 and 7.5 wt. % concentration of MoS2 particles are produced using stir casting technique, and mechanical and tribological properties are evaluated. Microstructural characterization of the hybrid composites revealed the uniform distribution of reinforcement (B4C and MoS2) particles in the matrix material. Hardness and fracture toughness of the hybrid composites are decreased monotonously with an increase in the addition of MoS2 particles. Dry sliding tribological studies conducted using a pin-on-disk tribotester under atmospheric conditions revealed the formation of MoS2-lubricated tribolayer on the worn pin surface which significantly influenced the tribological properties. The addition of MoS2 particles decreased the friction coefficient and wear rate of the hybrid composites. Delamination and abrasion are observed to be the controlling wear mechanisms and material in the form of platelet-shaped debris, and flow-type chip debris is formed, and a long and shallow crater on the worn pin surface of the hybrid composite is also observed.