Faculty Publications
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Item Experimental investigation and optimization of machining parameters for sustainable machining(Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2018) Varghese, V.; Ramesh, M.R.; Dupadu, D.A detailed investigation on the effects of cutting parameters and different cooling environments on machinability of austenitic stainless steel AISI 304 is presented in this study. The need for sustainable manufacturing and better surface quality urged to explore the merits of cryogenic cooling over the other conventional cooling techniques. The end milling experiments were designed based on three parameter and three-level design considering dry, wet, and cryogenic machining environments to have a comparative study. The machinability studies such as surface roughness, tool wear, cutting forces, chip morphology, and chip reduction coefficient were investigated and compared with different machining environments. The machining parameters were optimized using Taguchi-based grey relational analysis. The cryogenic machining had the most influence on milling of AISI 304 steel and resulted in the reduction of cutting forces, surface roughness, and chip reduction coefficient in comparison with the conventional wet and dry machining. © 2018, © 2018 Taylor & Francis.Item Tribological behaviour of monolayer and multilayer Ti-based thin solid films deposited on alloy steel(Institute of Physics Publishing helen.craven@iop.org, 2019) V Badiger, P.V.; Desai, V.; Ramesh, M.R.; Joladarashi, S.; Gourkar, H.The fretting wear and adhesive wear resistance of Ti-based thin solid films deposited on MDN121 steel substrate are evaluated. Plasma-assisted cathodic arc evaporation technique is used to develop the TiC-C monolayer coating and Ti/TiN/TiCN/TiN/TiCN multilayer coatings used in the study. FESEM-EDS, nanoindentation, Raman spectroscopy, optical profiler, and confocal microscope are used to characterise the coatings and wear tracks. Diamond-like carbon is observed in the microstructure of both the coatings. During the fretting analysis, the coefficient of friction (COF) is reduced by 68.49% in the case of the TiC-C monolayer coating and 42.46% in the Ti multilayer coatings as compared to the substrate. The volumetric wear loss of the TiC-C monolayer coating is lower than the multilayer coating. The wear surface morphology reveals the abrasive form of the fretting wear mechanism in both the monolayer and multilayer coatings whereas the galling failure in the substrate. During adhesive wear, the COF is reduced by 71.73% in the monolayer coating and 59.33% in the multilayer coatings compared to the substrate. The monolayer coating exhibits low friction and low wear rate as compared to the multilayer coating. © 2018 IOP Publishing Ltd.Item Hot corrosion behaviour of HVOF sprayed Ni3Ti and Ni3Ti + (Cr3C2 + 20NiCr) coatings in presence of Na2SO4-40%V2O5 at 650 °c(IOP Publishing Ltd custserv@iop.org, 2019) Reddy, N.C.; Koppad, P.G.; Reddappa, H.N.; Ramesh, M.R.; Babu, E.R.; Varol, T.Ni3Ti and Ni3Ti + (Cr3C2 + 20NiCr) coatings were deposited on gas turbine based ASTM B265 titanium (Ti-15) and AISI 420 stainless steel (MDN-420) substrate materials using HVOF technique. Thermocyclic hot corrosion tests were carried out at 650 °C in molten salt environment of Na2SO4-40%V2O5 for about 50 cycles. Thermogravimetric analysis was carried out to study the hot corrosion kinetics of uncoated and coated titanium and stainless steel substrates. The weight gain per unit area showed that the coated substrate materials displayed better resistance to hot corrosion when compared with that of uncoated substrate materials. The surface morphology of uncoated and coated substrate materials were analysed using scanning electron microscopy and elemental analysis. The formation of different types of oxides and compounds were analysed using x-ray diffraction. The uncoated substrates surface showed microspalling at several regions while coated substrates surface were composed of protective oxide layers. The presence of ternary NiCr2O4 protective oxides on the surface of Ni3Ti + (Cr3C2 + 20NiCr) coated substrates leads to reduction in the diffusion of corrosive species inside the coating. © 2019 IOP Publishing Ltd.Item Tribological performance of wire arc additive manufactured 347 austenitic stainless steel under unlubricated conditions at elevated temperatures(Elsevier Ltd, 2020) Duraisamy, R.; Subramaniyan, S.; Kannan, A.; Siva Shanmugam, N.; Sankaranarayanasamy, K.; Ramesh, M.R.Wire Arc Additive Manufacturing (WAAM) is an effective metal additive manufacturing process. In this research, 347 Austenitic Stainless Steel (ASS) walls were manufactured with ER347 consumable material. The microstructure of the WAAM processed 347 plate is entirely heterogeneous with changing grain morphology along the building direction and this is attributed to the complex cyclic thermal history during WAAM process. The microstructure is composed of columnar, cellular and equiaxed structures at various regions. The hardness decreased gradually from bottom to top along the building direction. The volume fraction of ferrite ranged from 0.5% to 4.2% at various regions and the presence of niobium carbide (NbC) was confirmed. The aim of the current work is to provide an outline of the WAAM processed 347 steel under dry sliding conditions at elevated temperatures. The elevated temperature wear mechanism has mild oxidative wear characteristic due to the formation of tribo-oxides on the wearing and sliding surfaces. However, the average coefficient of friction (COF) is lower for the WAAM processed 347 compared to 347 substrate. In all cases after initial running-in, the wear debris from the wearing and sliding surface forms mechanically mixed composite layer of tribo-oxides (Fe2O3, Fe3O4 and Al2O3). The worn surface at 200 °C presents different wear behavior compared to the samples at 400 °C and 600 °C. The wear at 200 °C is a typical adhesive wear, while the wear at 400?600 °C is mild oxidative wear. The increase in the percentage of Fe3O4 helps to heal the wear surface by forming a mechanically mixed composite layer. The characteristics of mild oxidative wear were elucidated. © 2020 The Society of Manufacturing EngineersItem High-Temperature Solid-Particle Erosion Behaviour of Plasma-Sprayed Fe17Cr2Ni0.18C/Cenosphere-Based Composite Coating(Springer Science and Business Media Deutschland GmbH, 2021) Hanumanthlal, S.; Siddaraju, C.; Ramesh, M.R.The present investigation deals to improve the solid-particle erosion resistance of boiler steel material. FeCrNiC and FeCrNiC with 5, 10 and 15wt.% cenosphere composite coatings were deposited on A387 Grade 22 steel using plasma spray technique. Powder and as-sprayed coatings are characterized using Scanning Electron Microscope (SEM), X-ray diffraction to study the surface morphology and cross section to study the nature of coatings deposited. Microhardness and adhesion strength of the coatings are evaluated. High-temperature solid-particle erosion behavior of these coating is evaluated at 300 ºC and 600 ºC at different impact angles. FeCrNiC + 15%Cenosphere designates higher hardness and adhesion strength. Convention weight change method cannot be used to validate the erosion performance due to undesirable variation. Optical profiler is used to determine erosion volume loss. The FeCrNiC coatings with the addition of cenospheres showed better erosion resistance than as-sprayed FeCrNiC and substrate. FeCrNiC + 10%Cenosphere coating shows the highest erosion resistance as compared to other coatings and substrate. Further increase in cenosphere percentage leads to reduction in erosion resistance due to predominant brittle fracture. High-temperature erosion is a concurrent erosion–oxidation process which shows combination of ductile and brittle erosion mechanism. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.Item Tribological behaviour of natural fibre 3D braided woven fabric reinforced PLA composites(SAGE Publications Ltd, 2021) Kanakannavar, S.; Jeyaraj, J.; Ramesh, M.R.This study aims to investigate the potential of natural fibre 3D braided woven fabric (NFBF) reinforced PLA (poly lactic acid) composites for tribological applications. Composites with different fibre contents are prepared using film stacking process and hot press methods. Friction co-efficient and wear rate of the composites are analysed using pin-on-disc tribometer under dry contact sliding condition and various operating conditions (velocity and load) for a fixed sliding distance of 3000 m. The morphology of the worn surfaces is studied using scanning electron microscope (SEM). The reinforcement of fibre with the PLA reduced the polymer film generation and improved the surface roughness significantly. Wear rate of the composites are decreased drastically compared to pure PLA. Composite with 35 wt.% of NFBF reinforcement showed better wear characteristics. © IMechE 2020.Item Solid Particle Erosion Behaviour of Plasma-Sprayed (WC–Co)/(Cr3C2–NiCr) Coatings(Springer Science and Business Media Deutschland GmbH, 2022) Reddy, G.M.S.; Ramesh, S.; Anne, G.; Ramesh, M.R.; Rao, T.N.; Patil, P.This study reports the high-temperature erosion behaviour of plasma-sprayed 35% (WC–Co)/65% (Cr3C2–NiCr) coating on MDN-420 alloy. Plasma spray coatings have always played a pivotal role in enabling industries to combat problems of premature degradation of components that operate in harsh environments. (WC–Co) + (Cr3C2–NiCr) coating is investigated for erosion under various laboratory-simulated conditions. Coating surface is characterized by using an optical microscope, scanning electron microscope (SEM), and X-ray diffraction (XRD). Porosity, microhardness, surface roughness, and adhesion strength of the coating are measured. The solid particle erosion test is conducted at the temperatures of 300 °C, 500 °C and 700 °C with the impact angles of 30° and 90° by using Al2O3 as an erodent in the hot air jet erosion testing machine. The optical profilometer is used to evaluate the erosion volume loss of the coated and uncoated samples. It is observed that erosion resistance of the substrate is found to be higher than the coating at the different test temperatures. As the temperature increases, the erosion resistance of the coating is also increased at all the temperatures for both impact angles of 30° and 90°.The eroded coating surface morphology reveals that the generalized behaviour of the coating is ductile in nature. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.Item Elevated temperature erosion performance of plasma sprayed NiCrAlY/TiO2coating on MDN 420 steel substrate(Institute of Physics, 2022) Reddy G, M.S.; Prasad, C.D.; Patil, P.; Naresh, N.; Ramesh, M.R.The current study deals with the erosion behaviour of a plasma-sprayed 70% NiCrAlY + 30% TiO2 coating on MDN 420 steel substrate at extreme temperatures. The coating was characterized by using an optical microscope, Scanning Electron Microscopy and X-ray diffraction methods. The coating's porosity, microhardness, surface roughness, and adhesion strength were all examined. The solid particle erosion experiments were carried out at temperatures of 300 °C, 500 °C, and 700 °C, with impact angles of 30° and 90°. The tests were conducted by using the alumina as an erodent in the hot air jet erosion testing machine. The erosion volume loss of coated and uncoated samples was measured using an optical profilometer. It is observed that erosion resistance of the coating was found to be more when compared to the substrate for the different test temperatures chosen. As the temperature increases, the erosion resistance of the coating also found increased from 300 °C to 700 °C at both impact angles of 30° and 90°. The morphology of the eroded coating surface reveals that the generalized behaviour of the coating is ductile in nature. © 2022 IOP Publishing Ltd.Item Investigation of thermally sprayed NiCrAlY/TiO2and NiCrAlY/Cr2O3/YSZ cermet composite coatings on titanium alloys(Institute of Physics, 2022) Madhu Sudana Reddy, G.; Prasad, C.D.; Patil, P.; Shetty, G.; Ramesh, M.R.; Nageswara Rao, T.The present work investigates the hot corrosion behavior of thermally sprayed 65 pct NiCrAlY + 35 pct TiO2 and 65 pct NiCrAlY + 30 pct Cr2O3 + 5 pct YSZ coatings on titanium 15 alloys. The coatings on the titanium 15 alloy substrates exhibit a near-uniform, dense, and adherent microstructure with a porosity of 2.7 to 2.9%. Thermogravimetric studies are made to examine the hot corrosion performance of coatings in a molten salt environment of Na2SO4 + 60%V2O5 at the temperature of 700 °C for 50 cycles. One cycle is carried out by heating for a period of one hour and cooling the sample at ambient conditions. The corrosion products are analyzed based on scanning electron microscopy, energy dispersive analysis, and X-ray diffraction techniques to study the morphology, phase composition, and abundance of the high-temperature corrosion constituents. The bare titanium-15 alloy, 65 pct NiCrAlY + 35 pct TiO2 coating and 65 pct NiCrAlY + 35 pct Cr2O3 + 5 pct YSZ coating produced a weight gain of 307.92 mg cm-2, 42.16 mg cm-2 and 44.02 mg cm-2 respectively after the period of 50 cycles. The effective resistance of the coatings is due to the formation of Ni3V2O8, NiCr2O4, Cr2O3 & AlV2O4 phases. © 2022 IOP Publishing Ltd.Item Green synthesis of CuO/MgO/ZnO nanoparticles using Costus pictus leaf extract for effective antibacterial applications(Elsevier B.V., 2024) Kumar, P.; Ramesh, M.R.; Doddamani, M.; Suresh, J.; Lingaraj, R.In recent years, environmentally friendly methods have garnered significant attention in developing novel nanoparticles (NPs). This study focuses on the green synthesis and characterisation of CuO/MgO/ZnO NPs using Costus pictus D. Don Plant extract as a green reducing and capping agent. X-ray diffraction (XRD) analysis was employed to assess the purity of NPs, whereas Fourier-transform infrared (FTIR) and UV–Vis spectroscopy were employed to study the chemical composition and absorption peaks of the synthesised NPs. The Field-emission scanning electron microscopy (FE-SEM) images revealed a distinctive flower-like morphology of NPs, and their stability and dispersion were supported by a negative zeta potential of −14.8 mV. The significant surface area (87.742 m2/g) of CuO/MgO/ZnO NPs was obtained from Brunauer-Emmett-Teller (BET) analysis. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) analysis confirmed that the particle size of NPs is nearly 50 nm and is poly-crystalline. Finally, the synthesised NPs were tested against the bacteria using the agar-well diffusion method. Notably, CuO/MgO/ZnO NPs exhibited better antibacterial activity against Pseudomonas aeruginosa, yielding a substantial inhibition zone of 23.33 ± 2.08 mm. © 2024 Elsevier B.V.