Temperature dependence of friction and wear performance and thermomechanical response of flyash-filled brake composites

Abstract

Flyash-filled glass fibre reinforced composites have been fabricated and evaluated for drag braking performance on a chase friction testing machine following SAE J 661a standard. The friction build-up and decay phenomena in the drag braking mode as a function of drum temperature have consistently been found to be in the composites with ∼5−7.5 wt% of glass fibres, whereas the absolute friction effectiveness remained higher in the composites with maximum flyash/maximum glass fibre contents. Temperature-dependent friction performance remained broadly composition specific and qualitative correlations of performance to compositional attributes have been found to be complex. Topographical variations and their possible roles in controlling the tribological performance have been characterized by worn surface morphology. Scanning electron microscopy–energy dispersive X-ray combined analysis have revealed that at higher amount of glass fibre content in combination with flyash, the composite exhibited enhanced noise and judder propensity apart from higher Fe-content deposition on friction film. The energy dissipation ability modes as revealed from dynamic mechanical analysis showed not only a correspondence between the damping ability of the composites and compositional variations but also qualitatively established a correlation between wear and storage moduli.