Goudar, D.M.Patil, I.S.Magalad, V.T.Rao, S.S.Herbert, M.A.2026-02-052022Advances in Materials and Processing Technologies, 2022, 8, 3, pp. 2684-26982374068Xhttps://doi.org/10.1080/2374068X.2021.1939551https://idr.nitk.ac.in/handle/123456789/22888The 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.eutectic Al-Si alloyhardnessMMCspray formingstir castingtensile strengthzirconium oxide