DEFORMATION BEHAVIOUR OF ALUMINIUM BASED COMPOSITES REINFORCED WITH SHALE AND COAL FLY ASH

Abstract

Aluminium Matrix Composites (AMCs) have limited ductility and toughness, which limits their processing windows during hot forming for complicated component designs such as those used in automobiles. To solve the above problems, this research incorporated shale and coal fly ash into aluminium matrix and investigated their deformation behaviour at ambient and elevated temperatures. Double stir casting process was used for the production of the composites, tensile test was carried out at room temperature, and hardness was carried out at room temperature, 180oC and 380oC, while isothermal compression testing was done at temperatures 180oC and 380°C at strain rates of 0.5 s-1 and 5 s-1. Gleeble 3500 thermomechanical simulator was used for the generation of data for evaluating the hot deformation behaviour, characterization of the hot deformation samples was carried out using X-Ray diffractometer (XRD), scanning electron microscope (SEM) and optical micrograph. The results obtained show that Al/CFA has the highest UTS value 182.73 MPa and the highest hardness value at room temperature, however the result show Al6063 at 180oC 0.5 s-1 and Al/CFA at 180oC 5 s-1 has the highest hardness value. The Al/CFA at 180oC, 5 s-1 requires the highest flow stress before yielding for the stress strain behaviour and it was observed that the flow stress reduced for the AMCs at high temperature of 380oC, the sample characterization show the (SEM) Al/CFA at 180oC, 5 s-1 has the smallest grain size 41.34 using numerical analysis. In general, the coal fly ash reinforced Aluminium matrix composites yielded the best combination of hot deformation parameters (Temp 180oC, 5 s-1 and 0.5 s-1) suitable for processing components for the target area of application.