Mechanical and Tribological Behavior of Warm Rolled Al-6Si-3Graphite Self Lubricating Composite Synthesized by Spray Forming Process

Abstract

In this investigation, the mechanical and tribological behavior of warm rolled Al-6Si-3Gr (graphite) self-lubricating composite have been studied. A spray forming process was used to synthesize the composite. The graphite particles were reinforced externally into the jet of the spray of molten Al-Si alloy. The porosity was generated under the spray forming process that was eliminated by the secondary process (warm rolling). Warm rolling was carried out with 20, 40, 60 and 80% thickness reduction in multi-passes on high non-reversing mills. Refinement and distribution of silicon and graphite particles in the composite were increased. The mechanical properties namely hardness and strengths were also improved by warm rolling. Wear properties of the composite after each thickness reduction were also investigated under dry sliding condition. Composite after warm rolling showed the better results in the coefficient of friction and wear rate. Wear properties improvement, nature of the debris particles and mechanical properties of the composite after warm rolling were discussed in details with its microstructural features. Different characterization techniques were also used to support the prediction of change in properties. The load bearing capacity of the composite was increased by warm rolling. These composites could be used for those applications where load bearing capacity and less wear is required.