Browsing by Author "Bhajantri, V."

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    A brief review on fly ash and its use in surface engineering
    (American Institute of Physics Inc. subs@aip.org, 2018) Bhajantri, V.; Krishna, K.; Jambagi, S.C.
    Fly ash is a by-product obtained from coal power plants. Over the past two decades, handling this industrial waste has been a great challenge for many developing countries. However, this menace can be used in many industrial applications viz., civil, automobile and aerospace applications. In civil industry, the fly ash has been used in concreate to enhance the porosity that increases the curing time of the concrete. The fly ash has been gaining importance these days as a feedstock material for many thermal spray processes. In automobile sector, the fly ash has been used as a thermal barrier coating in IC engines, whereas in aerospace industry, which demands lighter and stronger materials, the fly ash has been used as a reinforcement material. Hence, so far, fly ash has been used as an either single or a composite feed stock material in thermal spray processes. The fly ash with other materials like alumina, titania and red mud have been deposited using thermal spray processes. These coatings have exhibited higher wear, corrosion and erosion resistance as compared to the uncoated specimens. In this paper, a brief review on fly ash and its use, especially its use as a feed stock in thermal spray coating, is presented. Therefore, the use of fly ash has opened a new frontier of research in thermal spray coating area where economically viable coatings can be produced using industrial waste like fly ash. © 2018 Author(s).
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    A brief review on fly ash and its use in surface engineering
    (2018) Bhajantri, V.; Krishna, P.; Jambagi, S.
    Fly ash is a by-product obtained from coal power plants. Over the past two decades, handling this industrial waste has been a great challenge for many developing countries. However, this menace can be used in many industrial applications viz., civil, automobile and aerospace applications. In civil industry, the fly ash has been used in concreate to enhance the porosity that increases the curing time of the concrete. The fly ash has been gaining importance these days as a feedstock material for many thermal spray processes. In automobile sector, the fly ash has been used as a thermal barrier coating in IC engines, whereas in aerospace industry, which demands lighter and stronger materials, the fly ash has been used as a reinforcement material. Hence, so far, fly ash has been used as an either single or a composite feed stock material in thermal spray processes. The fly ash with other materials like alumina, titania and red mud have been deposited using thermal spray processes. These coatings have exhibited higher wear, corrosion and erosion resistance as compared to the uncoated specimens. In this paper, a brief review on fly ash and its use, especially its use as a feed stock in thermal spray coating, is presented. Therefore, the use of fly ash has opened a new frontier of research in thermal spray coating area where economically viable coatings can be produced using industrial waste like fly ash. � 2018 Author(s).
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    Comparative analysis of flipped and overlapped microwave sintered plus friction stir processed in-situ Al-Cu composites
    (Springer Nature, 2024) Vinayak, V.R.; Bajakke, P.A.; Jambagi, S.C.; Bhajantri, V.; Deshpande, A.S.
    The in-situ Al-Cu composites were fabricated with Cu content more than the solubility limit (5.65%) and the critical composition of an Al-Cu alloy (4.6%). A powder metallurgy route with state-of-the-art microwave sintering and friction stir process with overlapped and flipped conditions was attempted. The overlapped friction stir resulted in a minimum area of nugget region, unidirectional material mixing, high heat input in successive passes, and brittleness in the material. This accounted for the material to exhibit high strength with low ductility. Whereas flipped friction stir leads to a maximum area of stir zone, bidirectional material mixing, and similar thermal cycles in individual passes and avoids excessive heating. This facilitated the material to possess maximum strength by retaining ductility. The newly developed in-situ Al-Cu composite material (with Cu wt% in ranges of 8–12) possesses equivalent strength, ductility, electrical conductivity, and rate of corrosion compared to copper. Notably, these attributes, combined with its cost-effectiveness, position this material as a promising alternative to copper conductors in electrical applications. From the present investigation, it is strongly recommended to choose a flipped friction stir for better properties. © Qatar University and Springer Nature Switzerland AG 2024.
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    Experimental analysis on effect of various fillers on mechanical properties of glass fiber reinforced polymer composites
    (2019) Aveen, K.P.; Bhajantri, V.; D'Souza, R.; Londe, N.V.; Jambagi, S.
    Filler materials are the inert materials which are used in glass fiber reinforced polymer (GFRP) composites for modifying the chemical and physical properties of the matrix polymers to reduce material costs, to improve processability, to improve product performance or to simply act as extenders or matrix diluents. Effect of fillers on mechanical properties like tensile strength, flexural strength, tensile modulus, impact strength, hardness was tested by various methods experimentally. The present work focused on fabrication of Glass Epoxy composite with Mother of pearl, fly ash and aluminum powder used as filler material. The Filler material was varied in % composition by 3%, 6% and 9% in the total volume. This study was carried in order to determine the mechanical properties of fabricated composite by conducting Tensile and Flexural tests. The tests showed the composite with aluminum filler material exhibits better tensile property and composite with fly ash filler exhibits better flexural property. � 2018 Author(s).
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    Experimental analysis on effect of various fillers on mechanical properties of glass fiber reinforced polymer composites
    (American Institute of Physics Inc. subs@aip.org, 2019) Aveen, K.P.; Bhajantri, V.; D'Souza, R.; Neelakantha, N.V.; Jambagi, S.
    Filler materials are the inert materials which are used in glass fiber reinforced polymer (GFRP) composites for modifying the chemical and physical properties of the matrix polymers to reduce material costs, to improve processability, to improve product performance or to simply act as extenders or matrix diluents. Effect of fillers on mechanical properties like tensile strength, flexural strength, tensile modulus, impact strength, hardness was tested by various methods experimentally. The present work focused on fabrication of Glass Epoxy composite with Mother of pearl, fly ash and aluminum powder used as filler material. The Filler material was varied in % composition by 3%, 6% and 9% in the total volume. This study was carried in order to determine the mechanical properties of fabricated composite by conducting Tensile and Flexural tests. The tests showed the composite with aluminum filler material exhibits better tensile property and composite with fly ash filler exhibits better flexural property. © 2018 Author(s).
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    Influence of carbon nanotube reinforcement on the heat transfer coefficient, microstructure, and mechanical properties of a die cast Al-7Si-0.35Mg alloy
    (Elsevier Ltd, 2021) Usef, A.P.; Bhajantri, V.; Kannoth, V.; Jambagi, S.C.
    Al-7Si-0.35Mg or A356 alloy is most widely used in aircraft and automobile industries owing to its high strength to weight ratio. This alloy has been reinforced with a 1 wt% carbon nanotube (CNT) to improve its properties in this investigation. First, A356/1 wt% CNT powders were ball milled in the presence of ethanol and subsequently consolidated using gravity die casting. Ball milling was effective in achieving homogeneous dispersion of CNT. The microstructural study revealed the segregation of the Al4C3 phase at the grain boundary. This mechanism is known as grain boundary precipitation. Also, the grain size has decreased by ~44%. Next, the casting-die interfacial heat transfer coefficient (IHTC) has been evaluated using Beck's inverse heat transfer algorithm. With the reinforcement, the IHTC has increased by ~2.5%, which indicates the rise in heat transfer rate during solidification. Then, the experimental and theoretical tensile properties of A356 were correlated using simulation software. The experimental results showed the synergistic effect of grain size, Al4C3, and IHTC improving yield strength by ~19.8%, ultimate tensile strength by ~14.13%, elongation by 7%, and hardness ~22%. Therefore, a meagre 1 wt% CNT has improved the heat transfer rate of the melt as indicated by IHTC values. This effect was further corroborated by evaluating the thermal conductivity of the sample. The thermal conductivity has improved by 10% that resulted in finer grain size of the sample. Therefore, such reinforced alloys are expected to display higher strength demanded in various industrial applications. © 2021
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    Unidirectional flipped multiple-pass friction stir process: an innovative step in the fabrication of in situ Al-Cu composites
    (Springer Science and Business Media Deutschland GmbH, 2024) Bajakke, P.A.; Vinayak, V.; Jambagi, S.C.; Bhajantri, V.; Deshpande, A.S.
    The in situ Al-Cu composites were manufactured by powder metallurgy with state-of-the-art microwave sintering tailed by friction stir process in two different ways: unidirectional overlapped two-pass and unidirectional flipped two-pass. Novelty is claimed in the flipped process. An attempt was made to investigate the addition of copper beyond the solubility limit and the critical composition of an Al-Cu alloy (4.6 wt.%). The overlapped process enforced higher temperature, cumulative strain, and strain rate. Since Al and Cu are high-stacking fault energy metals, both dynamic recrystallization and dynamic recovery occurred and resulted in grain refinement and higher fractions of Al2Cu. The self-hard and brittle nature of Cu and Al2Cu improved strength (Al-3wt.%Cu, 231.23 MPa), hardness (Al-6wt.%Cu, 82.5 HV), and deteriorated ductility (Al-7wt.%Cu, 5.2%). The formed Al2Cu at the interface were surrounded by Al particles and formed passive films Al2O3 and Cu2O enhanced corrosion resistance (Al-5wt.%Cu, 0.00717191 mpy). The process densely compacted the material, minimized porosity, decreased dislocation density, and increased strain aided in better electrical conductivity (Al-5wt.%Cu, 145.92%IACS). The flipped process circumvented excessive heating and embrittlement of the material thereby improving strength without loss of ductility (Al-7wt.%Cu, 235.85 MPa and 25.53%). Al-3wt.%Cu with minimum corrosion current (5.681 µA/cm2) exhibited maximum resistance to corrosion (0.169852 mpy). The highest electrical conductivity was noticed for (Al-5wt.%Cu, 104.17%IACS). © The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature 2024.