Experimental Investigation and Optimisation of Mechanical and Microstructure Behaviour of Stir Cast and Hot-Pressed Al-12.5%Si-ZrO2 Composites: Taguchi and Super Ranking Concept

Abstract

Stir cast processing route was employed to prepare the composite. Taguchi experimental plan with a set of parameters such as stir speed, stir time, ZrO<inf>2</inf> % reinforcement, and casting temperature were studied to know their influence on the composite properties. ZrO<inf>2</inf> % reinforcement, followed by stir speed, is the most dominant factor influence on composite properties. Super ranking concept determined stir casting optimal condition resulted in 25.02% and 5.64% increase in ultimate tensile strength and hardness, whereas 37.68% reduced wear loss of composites compared to initial stir casting conditions. The hot-pressing parameters (pressure, temperature, and dwell time) were analyzed to know the process insights on composite properties. The pressure is the most dominating factor followed by temperature on all the properties of composites. Super ranking concept determined optimal hot-pressing conditions showed a 39.3% reduction in wear loss, 11.54% and 4.88% increase in ultimate tensile strength and hardness values compared to initial hot-pressing condition, respectively. Applying a hot-pressing technique on the optimized conditions of stir casted parts resulted in 40.7% reduction in wear loss, 19.71% and 9.5% increase in ultimate tensile strength and hardness values. The difference in properties obtained for samples fabricated correspond to initial, and optimal conditions of stir casting and hot-pressing technique was strongly justified with resulted microstructures and worn surface morphologies. © 2021 Informa UK Limited, trading as Taylor & Francis Group.