Faculty Publications

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2016 - 20182

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Author: search.filters.author.Prabhu, K.N.Subject: search.filters.subject.Cerium

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    The effect of simultaneous refinement and modification by cerium on microstructure and mechanical properties of Al-8% Si alloy
    (Taylor and Francis Ltd. maney@maney.co.uk, 2016) Vijayan, V.; Prabhu, K.N.
    The effect of cerium melt treatment on microstructure and mechanical properties of gravity die cast Al-8% Si alloy was studied. The addition of Ce transformed the large columnar ?-Al grains into fine equiaxed grains and modified the acicular eutectic Si into fine fibrous form. The addition of Ce resulted in the formation of needle-shaped complex Ce intermetallic along the grain boundaries. Electrical conductivity measurements are used for the first time to reveal the effect of Ce addition on modification of the eutectic Si. The electrical conductivity of the alloy increased with Ce melt treatment. Scanning Electron Microscopy results suggests that the Ce particles did not heterogeneously nucleate the ?-Al grains, instead the fine equiaxed grains were formed through an invariant reaction between the liquid melt and Ce phase. The ultimate tensile strength, % elongation and hardness of the alloy significantly improved due to simultaneous modification and refinement. © 2016 Informa UK Limited, trading as Taylor & Francis Group.
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    Thermal Analysis of Cerium-Treated Chill-Cast Al-23 Si Alloy
    (Springer New York LLC barbara.b.bertram@gsk.com, 2018) Vijayan, V.; Prabhu, K.N.
    The influence of elemental cerium addition on the cooling curve parameters and microstructure of hypereutectic Al-23Si alloy was investigated in this work. The cooling rate of the treated and untreated alloy samples was varied by solidifying the melt against chills of different materials in a stainless-steel tube. The cooling curve was recorded and nucleation temperatures of various phases in the alloy were measured. The results show that the chilling improves the effectiveness of the modifier. The two main phases of the alloy, primary silicon and eutectic silicon, were nucleated at temperatures of about 661.2 and 571.6 °C, respectively. The addition of Ce to slowly cooled alloys resulted in an increase in undercooling temperature of both the phases, with a decrease in its nucleation temperature, whereas the same additions increased the nucleation temperatures in chilled alloys. Based on the thermal analysis results, a relation between thermal analysis parameter (? TG) and silicon particle size of the alloy was proposed. © 2018, ASM International.