Faculty Publications

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2013 - 20173

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Author: search.filters.author.Vijayan, V.Subject: search.filters.subject.Microstructure and mechanical properties

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    The effect of the addition of strontium and cerium modifiers on microstructure and mechanical properties of hypereutectic Al-Si (LM30) alloy
    (ASTM International, 2013) Vijayan, V.; Ravi, M.; Prabhu, K.
    The present work deals with the melt treatment of LM30 hypereutectic Al-Si alloy using cerium and strontium and the assessment of its effect on microstructure and properties of the alloy. The addition of cerium simultaneously modified both primary and eutectic silicon, leading to an increase in ultimate tensile strength, as well as the wear resistance of the alloy. It was found that the coefficient of thermal expansion of the alloy decreased on modification of the microstructure. © 2013 by ASTM International.
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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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    The Effect of Chilling and Ce Addition on the Microstructure and Mechanical Properties of Al-23Si Alloy
    (Springer New York LLC barbara.b.bertram@gsk.com, 2017) Vijayan, V.; Prabhu, K.
    The present work involves the study of the effect of varying concentration of Ce addition on microstructure and mechanical properties of Al-23%Si alloys. Melt-treated alloys were solidified in copper, brass, stainless steel molds to assess the effect of cooling rate. The effect on microstructure was assessed by measuring the fineness of primary silicon and eutectic silicon particle characteristics. The Ce melt treatment transformed the coarse and irregular primary silicon into refined polyhedral silicon crystals, and the effect was more significant at higher cooling rates. Although the melt treatment had refined the eutectic silicon at lower cooling rates, it did not show any considerable effect on the eutectic silicon at higher cooling rates. The mechanical properties of the alloy increased significantly with increase in cooling rates and cerium concentration. Analysis of the results and literature reveals that the refined primary silicon was formed as a result of an invariant reaction between Ce compounds and primary silicon at higher temperatures. © 2016, ASM International.