Faculty Publications
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Item Determining the solidification characteristics of Manganese bronze (MAB) alloy using computer-aided cooling curve analysis(Elsevier Ltd, 2022) Pranesh; Mohammed Anas, S.; Johnson, S.; Jose, R.; Sachin, B.; Cadambi, S.; Vijayan, V.; Karinka, S.Computer-aided cooling curve analysis (CACCA), known for its reliability and simplicity was used to study the material properties of manganese bronze (MAB) alloy. MAB alloy, due to its high strength and corrosion resistance, is a staple material for marine applications. Since the alloy is difficult to machine, non-heat treatable, and complex to fabricate, casting is the only cost-effective process of producing products of the material. As the literature is scant on the MAB's high-temperature properties, this study is aimed at determining the thermo-physical properties of the alloy required for casting simulation by carrying out Newtonian and Fourier analysis of the recorded temperature of the solidifying alloy from liquidus state. © 2022 Elsevier Ltd. All rights reserved.Item Cu-44Ni-5Cr alloy has been subjected to thermomechanical treatment which consisted of plastic deformation of as-quenched material by 50, 65 and 80% reduction in thickness followed by ageing in the interval of 500 to 650 °C for various durations of time. Progress in age-hardening was studied by means of hardness measurement and X-ray diffraction studies. The wavelength of composition modulation and strain amplitude were measured. It was found that age-hardening was a result of interaction between spinodal decomposition and recovery processes. Prior deformation was found to enhance the kinetics of both spinodal decomposition and coarsening. It was concluded that this resulted from increased vacancy concentration and increased coherency strain in the cold-worked material. © 1994 Chapman & Hall.(Kluwer Academic Publishers, Effect of thermomechanical treatment on the phase transformation in Cu-44Ni-5Cr alloy) Raghavendra Bhat, R.; Prasad Rao, P.1994Item Progress in spinodal decomposition of a Cu-32Ni-2Cr alloy subjected to quench?age and quench?work?age treatments have been studied through hardness measurements as well as by X-ray diffraction techniques. It is found that recovery processes occur during early stages of aging which are interpreted in terms of the migration of matrix dislocations to interfaces. The kinetics of spinodal decomposition is found to be enhanced by prior deformation. Thermomechanical treatment results in a substantial increase in strength.(Publ by Carl Hanser Verlag GmbH & Co, Thermomechanical treatment of spinodal Cu-32Ni-2Cr alloy) Bhat, R.Raghavendra; Prasad Rao, P.1994Item Effect of mushy state rolling on age-hardening and tensile behavior of Al-4.5Cu alloy and in situ Al-4.5Cu-5TiB2 composite(Elsevier Ltd, 2011) Siddhalingeshwar, I.G.; Herbert, M.A.; Chakraborty, M.; Mitra, R.The effect of mushy state rolling on aging kinetics of stir-cast Al-4.5Cu alloy and in situ Al-4.5Cu-5TiB2 composite and their tensile behavior in solution-treated (495°C) or differently aged (170°C) conditions, has been investigated. As-cast or pre-hot rolled alloy and composite samples were subjected to single or multiple mushy state roll passes to 5% thickness reduction at temperatures for 20% liquid content. Peak-aging times of mushy state rolled composite matrices have been found as ?7.5-10% of that of as-cast alloy. Such enhancement in aging kinetics is attributed to homogeneity in Cu atom distribution as well as increase in matrix dislocation density due to thermal expansion coefficient mismatch between Al and TiB2, matrix grain refinement and particle redistribution, achieved by mushy state rolling. Uniform precipitate distribution in mushy state rolled composite matrices leads to greater peak-age microhardness with higher yield and ultimate tensile strengths than those in as-cast alloy and composite. © 2010 Elsevier B.V.Item Comparison of spreading behaviour and interfacial microstructure in Sn-0·7Cu, Sn-0·3Ag-0·7Cu and Sn-2·5Ag-0·5Cu lead free solder alloys on Fe-42Ni substrate(Maney Publishing michael.wagreich@univie.ac.at, 2013) Satyanarayan, S.; Prabhu, K.In the present work, spreading behaviour and development of interfacial microstructure in Sn- 0·7Cu, Sn-0·3Ag-0·7Cu and Sn-2·5Ag-0·5Cu lead free solder alloys on Fe-42Ni substrates having two different surface textures were investigated. Smooth textured surfaces yielded better wettability than rough surfaces particularly for Sn-0·7Cu solder alloy. Wettability of Sn-0·7Cu solder on rough textured surfaces was found to be poor compared to other solder alloys. Spreading of Sn-0·7Cu solder on substrate surface showed longer viscous regime, Sn-2·5Ag- 0·5Cu solder exhibited shortest viscous regime. Sn-0·3Ag-0·7 solder showed intermediate behaviour. Sn-Cu solder alloy exhibited needle and coarse shaped (Cu,Ni)6Sn5 intermetallics at the interface and in the matrix of the solder alloy on smooth substrate, whereas on rough substrate, formation of only coarse shaped (Cu,Ni)6Sn5 intermetallic compounds (IMCs) was observed. For Sn-0·3Ag-0·7Cu solder alloy, Fe-Ni-Sn and FeSn2 IMCs identified at the interface. (Cu,Ni)6/Sn5 IMCs were found to be less coarser than as observed at Sn-0·7Cu/substrate interface. Sn-2·5Ag-0·5Cu alloy exhibited (Cu,Ni) 3Sn4 and (Cu,Ni)6 Sn5 IMCs at the interface and in the bulk of solder alloy. © 2013 Institute of Materials, Minerals and Mining.Item Spreading behavior and evolution of IMCs during reactive wetting of SAC solders on smooth and rough copper substrates(2013) Satyanarayan, S.; Prabhu, K.The effect of surface roughness of copper substrate on the reactive wetting of Sn-Ag-Cu solder alloys and morphology of intermetallic compounds (IMCs) was investigated. The spreading behavior of solder alloys on smooth and rough Cu substrates was categorized into capillary, diffusion/reaction, and contact angle stabilization zones. The increase in substrate surface roughness improved the wetting of solder alloys, being attributed to the presence of thick Cu 3Sn IMC at the interface. The morphology of IMCs transformed from long needle shaped to short protruded type with an increase in the substrate surface roughness for the Sn-0.3Ag-0.7Cu and Sn-3Ag-0.5Cu solder alloys. However, for the Sn-2.5Ag-0.5Cu solder alloy the needle-shaped IMCs transformed to the completely scallop type with increase in the substrate surface roughness. The effect of Ag content on wetting behavior was not significant. © 2013 TMS.Item Solder joint reliability of Sn-0·7Cu and Sn-0·3Ag- 0·7Cu lead-free solder alloys solidified on copper substrates with different surface roughnesses(2013) Satyanarayan, S.; Prabhu, K.The bond shear test was used to assess the integrity of Sn-0·7Cu and Sn-0·3Ag-0·7Cu lead-free solder alloy drops solidified on copper substrates with smooth and rough surface finishes. Solder alloys solidified on smooth substrates required higher shear force compared to that on rough substrates. Sn-0·3Ag-0·7Cu alloy required higher shear energy than Sn-0·7Cu alloy. Solder alloys solidified on smooth substrate surfaces exhibited complete ductile failure. On rough copper surfaces, solder alloys showed a transition ridge characterized by sheared intermetallic compounds (IMCs) and the presence of dimples. The peak shear strength decreased with increase in contact area of the solder bond on the substrate. Smooth surface and the presence of minor amount of Ag in the solder alloy enhance the integrity of the solder joint. © 2013 Institute of Materials, Minerals and Mining.Item The influence of the addition of 4.5 wt.% of copper on wear properties of Al-12Si eutectic alloy(Hashemite University huniv@hu.edu.jo, 2015) Channappagoudar, S.; Kiran Aithal, K.; Sannayallappa, N.; Desai, V.; Mukunda, P.G.The influence of 4.5 wt.% copper addition on wear behavior of as-cast Al-12Si alloy prepared by gravity casting is investigated in dry sliding against a steel counterface using a pin-on-disk apparatus. The microstructures of test alloys and worn surfaces were examined by scanning electron microscopy and energy dispersing X-ray spectroscopy. The addition of copper to the binary Al-12Si alloy led to the precipitation of CuAl2 phase. Copper addition resulted in a refinement of ?-Al and a minor modification of eutectic Si. The Al-12Si-4.5Cu alloy showed a higher wear resistance as compared to Al-12Si binary eutectic alloy. © 2015 Jordan Journal of Mechanical and Industrial Engineering. All rights reserved.Item Effect of electrode material in wire electro discharge machining characteristics of Ti50Ni50-xCux shape memory alloy(Elsevier Inc. usjcs@elsevier.com, 2015) Manjaiah, M.; Narendranath, S.; Basavarajappa, S.; Gaitonde, V.N.Abstract TiNiCu alloy belongs to new class of shape memory alloy (SMA), which exhibits superior properties like shape memory effect, super elasticity and reversible martensitic transformation phase and thus find broad applications in actuators, micro tools and stents in biomedical components. Even though, SMA demonstrates outstanding property profile, traditional machining of SMAs is fairly complex and hence non-traditional machining like wire electric discharge machining (WEDM) has been performed. Hence, there is a need to investigate the WEDM performance characteristics of shape memory alloys due to excellent property profile and potential applications. In the present investigation, various machining characteristics like material removal rate (MRR), surface roughness, surface topography and metallographic changes have been studied and the influence of wire material on TiNiCu alloy machining characteristics has also been evaluated through ANOVA. Ti50Ni50-xCux=10, 20 was prepared by vacuum arc melting process. The proposed alloy as-cast material exhibits austenite property (B2 phase) and having higher hardness when compared to TiNi alloy. The investigation on WEDM of Ti50Ni50-xCux alloy reveals that the machining parameters such as servo voltage, pulse on time and pulse off time are the most significant parameters affecting MRR as well as surface roughness using both brass and zinc coated brass wires. However, machining with zinc coated brass wire yields reduced surface roughness and better MRR and also produces less surface defects on the machined surface of Ti50Ni50-xCux alloys. © 2015 Elsevier Inc. All rights reserved.Item Influence of combined grain refinement and modification on the microstructure, tensile strength and wear properties of Al-15Si, Al-15Si-4.5Cu alloys(Carl Hanser Verlag Kolbergerstrasse 22 Munchen D-81679, 2015) Channappagoudar, S.; Sannayallappa, N.; Desai, V.; Venkateswarlu, V.Microstructure, tensile strength and dry sliding wear studies of Al-15Si, Al-15Si-4.5Cu alloys with and without grain refinement and modifications are presented. Experimental alloys such as Al-15Si and Al-15Si-4.5Cu were conventionally melted and gravity die cast. For grain refinement, 1 wt.% of Al-1Ti-3B and for modification, 0.17 wt.% of aluminum phosphide (AlP) and 0.4 wt.% of Al-10Sr were added to the alloy melt. The results reveal refined microstructure due to grain refinement, modification, improved hardness, higher tensile strength and better sliding wear. Moreover, Al-15Si-4.5Cu alloy (untreated and treated) showed improved mechanical properties as compared to conventional hypereutectic Al-Si alloy. © Carl Hanser Verlag GmbH & Co. KG.