Browsing by Author "Goudar, D.M."

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    A comparative study of tensile properties of eutectic Al-Si / ZrO2 composites fabricated by spray forming and stir casting methods
    (Taylor and Francis Ltd., 2022) Goudar, D.M.; Patil, I.S.; Magalad, V.T.; Rao, S.S.; Herbert, M.A.
    The study aims to investigate the microstructural and mechanical  properties of Al-12.5%Si matrix composites reinforced with ZrO2 were fabricated by spray forming method and stir casting (SC) technique  by varying reinforcement of  2%, 6% and 10 wt.% ZrO2 powder (size 25 ?m).The spray-formed (SD) composites were subjected to hot (400°C) isostatic pressing to reduce the porosity. The microstructure of spray-formed and SC composites were examined using optical and SEM/ EDS. The microstructure of the spray-formed composites showed uniform distribution of fine Si, eutectic phase and ZrO2 particles in the equiaxed Al-matrix. In contrast, SC composites consist of a coarse Si, needle like eutectic phase and clustering of reinforcement particles at grain junctions as a continuous network along the grain boundaries. The hardness, ultimate tensile strength of both spray-formed and SC composites improved as the ZrO2 content increased, while yield strength decreased. Spray-formed composites showed better mechanical properties. This was attributed to uniform distribution fine of Si particles, reinforced particles, equiaxed matrix induced during spray deposition process. Tensile fracture surface of spray-formed composites possess ductile and cleavage fractures. SC composites showed intragranular cracks in coarse Si particles and increase in micro-cracks  with  increasing reinforcement. © 2021 Informa UK Limited, trading as Taylor & Francis Group.
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    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
    (Taylor and Francis Ltd., 2022) Patil, I.S.; Anarghya, A.; Rao, S.S.; Herbert, M.A.; Goudar, D.M.
    Stir cast processing route was employed to prepare the composite. Taguchi experimental plan with a set of parameters such as stir speed, stir time, ZrO2 % reinforcement, and casting temperature were studied to know their influence on the composite properties. ZrO2 % 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.