Faculty Publications
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Item Tribological Response of Magnesium/Glass Microballoon Syntactic Foams(Springer Science and Business Media Deutschland GmbH, 2022) Manakari, V.; Parande, G.; Doddamani, M.; Srivatsan, T.S.; Gupta, M.Magnesium (Mg)-based materials have great potential to replace the existing aluminum alloys and steels used in applications spanning the industries of defense, aerospace, and automotive due in essence to their excellent specific strength [σ/ρ], damping characteristics, and impact resistance. In this research study, we design an ultralow density magnesium/glass microballoon (GMB) syntactic foam having a density of 1.47 g/cc using the technique of Disintegrated Melt Deposition (DMD). The resultant material offered a healthy combination of extraordinary properties outperforming the existing aluminium and iron syntactic foams in terms of a noticeable improvement in specific strength [σ/ρ]. Further, the wear resistance of magnesium under dry sliding conditions showed a significant enhancement (~2.5 times) following the addition of glass microballoon (GMB). Abrasion and oxidation were identified to be the dominant wear mechanisms post worn-surface analysis. Morphology of the worn specimen provided clean, clear, and convincing evidence for the occurrence of delamination wear, which has traditionally limited the competitive advantage of magnesium and its alloy counterparts for selection and use in safety–critical components in transportation vehicles. This can be effectively overcome by the development of the proposed syntactic foams, which provide a unique cushioning effect against the applied load. © 2022, The Minerals, Metals & Materials Society.Item Fundamentals of multifunctional nanostructured coatings with recent updates(Elsevier, 2025) Poddar, M.K.; Soman, V.This chapter provides a comprehensive overview of nanocoatings and their diverse applications. Nanocoatings are characterized by their nanoscale dimensions, typically ranging between 1 and 100nm and high-surface-to-volume ratios. They showcase remarkable properties such as protection against corrosion, wear, microbial action, and UV radiation and provide superior optical, electrical, and surface properties. Compared to the conventional coatings, the synthesis of nanocoating involves very little use of volatile organic compounds. Nanocoating is fabricated using synthesis techniques like chemical vapor deposition, electrodeposition, and Particle Vapor Deposition, etc. This chapter also discusses different types of nanocoatings reported in scientific literature, each with many applications. Ceramic-based nanocoatings, which are oxide-based ceramics like alumina (Al2O3), zirconia (ZrO2), and titania (TiO2), etc, are highlighted for their remarkable hardness and suitability for wear and corrosion-prone applications. Also, the applicability of polymer and metal matrix-based nanocoatings in packaging, automotive, thermal protection, and solar energy harnessing is emphasized; these nanocoatings find extensive potential in industries such as aerospace, transportation, and manufacturing, where superior mechanical properties and wear resistance are inevitable. To bring nanocoatings to a large scale in the future, it is essential to adapt cost-effective strategies and evaluate the adhesion between substrate and coating. Mathematic models may be developed to simulate various properties. Nature-inspired models could efficiently design nanocoatings, such as the lotus leaf effect. We also address some of the environmental challenges associated with nanocoating and emphasize the importance of considering factors like size, capping agent, and shape to mitigate such challenges. Nanocoatings offer great potential in enhancing material performance, protecting surfaces, and addressing industry challenges. © 2025 Elsevier Ltd. All rights are reserved.Item Tribological Performance of Fe-Based Composite Coatings Under Elevated Temperature Conditions(Springer, 2025) Chandramouli, T.V.; Joladarashi, S.; Ramesh, M.R.The present study investigated the tribological performance of Fe-based coatings reinforced with carbides onto a maraging steel substrate using the HVOF spray technique. These materials are widely used in manufacturing various components in the aerospace and energy sectors. Commercially available SS316L and 17-4PH are reinforced with WC–Co feedstock powders to deposit these composite coatings on maraging steel substrate. The dry sliding wear tests were conducted using the ball-on-disc tribometer at varying temperatures (25 and 300 °C) with 10 N normal load using an alumina ball (Al2O3) as the counter body. The study includes micro-hardness, porosity, density, bond strength, and surface roughness of the coatings. The samples subjected to wear testing were analyzed using SEM/EDS and XRD techniques, and the wear scar volume was measured using a 3D profilometer to calculate the volume metric loss. The wear rate of SS316L30%WC–Co is 64.46% lower than that of 17-4PH30%WC–Co at room temperature and 67.33% lower at 300 °C under a load of 10 N. At room temperature, the worn surface exhibited abrasive wear, while at 300 °C, adhesive wear and oxidative wear were observed owing to the formation of protective layers. Therefore, SS316L-30%WC–Co demonstrates superior wear resistance compared to 17-4PH-30%WC–Co and offers enhanced mechanical strength, particularly in challenging environments. The deposition of these coatings effectively protects the maraging steel substrate. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.Item Tribological aspects of Al and Mg composites(Elsevier, 2025) Koppad, P.G.; Joladarashi, S.; Ramesh, M.R.; Keshavamurthy, R.It is well known that the technical function of a large number of engineering components/parts depends on motion. However, the term motion here is not as simple as it sounds, because it comes with consequences in the form of friction and wear. Along with lubrication, the science that deals with friction and wear is known as tribology. Therefore, it is necessary to pay more attention to tribology and acquire knowledge on the tribological behavior of materials, as the tribological characteristics such as friction and wear have been causing poor efficiency in engineering structures, huge economic losses, and environmental impacts. One way of addressing these issues lies in the development of lightweight materials based on metals such as aluminum and magnesium. Although one cannot employ these metals in their pure form, but modification in their microstructure and properties can certainly address the needs required for tribological applications. Keeping this in mind, this chapter covers the properties of aluminum and magnesium metals, basic aspects of tribology and most importantly, the work carried out on the friction and wear behavior of aluminum- and magnesium-based composites. The importance of this chapter lies in promoting better knowledge of the tribological behavior of aluminum and magnesium composites, especially from a various wear parameters point of view. The influence of material composition and wear parameters on tribological behavior is covered with a follow-up section on numerical and optimization methods employed for predicting tribological characteristics. © 2026 Elsevier Inc. All rights reserved..Item Wetting behaviour of a Green cutting fluid (GCF); influence of surface roughness and surface energy of AA5052, Ti6Al4V and EN31(Elsevier Ltd, 2022) Edachery, V.; Ravi, S.; Badiuddin, A.F.; Tomy, A.; Kailas, S.V.; Suvin, P.S.Green Cutting fluids (GCFs) are biodegradable and eco-friendly alternatives that can be employed in metalworking processes. They facilitate better tool service life and surface quality by removing the heat built, reducing coefficients of friction at tool-chip, and tool-work interfaces, flushing away the chip and preventing the formation of Built-up edges (BUEs). Conventionally, mineral oil (MO) based CFs are used, which can cause serious health hazards in humans as well as negatively impact the environment. Sustainable Green-cutting fluids (GCF) were found to be the solution for reducing the issues raised by the MO-based cutting fluids. The GCF used in the present study was synthesized using coconut oil (Cocos Nucifera) as the base, which is a clean, bio-degradable and eco-friendly substitute for petroleum-based mineral oils. This work is focused on experimentally determining the effectiveness of green cutting fluids on surfaces of (Aluminium)AA5052, (Titanium alloy)Ti6AL4V and Steel(EN31) with various surface topographies. In order to do so, the wetting properties were measured by a stable contact angle θ between the solid–liquid surface and the vapour-liquid interface. Wettability responses from the roughened surfaces in the range of 0.06–2.1 µm was evaluated using a profilometer and contact angle goniometer. Results show that the wetting characteristics of GCF are comparable to that of the MO-based CFs and can be a viable alternative, thus reducing the adverse effects on the environment. In conclusion, this study shows the potential of GCFas an alternative to MO-based cutting fluids used in machining operations in the manufacturing industries. © 2022Item Investigations on the effect of ball burnishing parameters on surface hardness and wear resistance of HSLA dual-phase steels(2008) Rao, D.S.; Hebbar, H.S.; Komaraiah, M.; Kempaiah, U.N.Surface finish has a vital influence on most functional properties of a component like fatigue life, wear resistance, corrosion resistance, etc. This has given birth to processes such as lapping, honing, burnishing, etc. Burnishing is a fine finishing operation involving the cold working plastic deformation of surface layers to enhance the surface integrity and the functional utility of a component. The present study has been carried out to establish the effect of burnishing parameters viz. feed rate, speed, force, ball diameter and lubricant on surface hardness, and wear resistance of HSLA dual-phase steel specimens. The result indicates that burnishing parameters have significant effect on the surface hardness and wear resistance.Item A comparative study on properties of porous friction course mixes with neat bitumen and modified binders(2009) Suresha, S.N.; George, V.; Ravi Shankar, A.U.R.This paper summarises details of the laboratory investigation on the effect of various binders on the performance and durability of porous friction course (PFC) mixes. Three different modified binders and neat bitumen were investigated for three different aggregate gradations at two predetermined binder contents. The performance was evaluated in terms of stone-on-stone contact condition, air voids, and hydraulic-conductivity of compacted PFC mixes. The structural durability was investigated based on aged abrasion loss and moisture susceptibility. The findings provide a better understanding of the effect of each binder type on the performance and durability of PFC mixes. Crown Copyright © 2008.Item Characterization of porous friction course mixes for different Marshall compaction efforts(2009) Suresha, S.N.; George, V.; Ravi Shankar, A.U.R.Porous friction courses (PFCs) are mainly recommended as surface drainage layers on high-speed road-corridors and runway pavements. Permeability and sound attenuation characteristics are considered to be the indices for performance assessment of PFCs. One of the reasons for the loss of permeability in PFCs is densification under heavy traffic. But, resistance to ravelling too, is of main concern in the case of under-compacted PFCs. This paper summarises the details of laboratory investigation on the characterization of PFC mixes corresponding to four different gradations and two binder contents, for three levels of the Marshall compaction. The findings of the investigation suggest that the selection of the compaction level for PFC mix design should be based on the design traffic level, and the gradation selected. © 2009 Elsevier Ltd. All rights reserved.Item Evaluation of properties of porous friction course mixes for different gyration levels(2009) Suresha, S.N.; George, V.; Shankar, A.U.R.Porous frictions courses (PFCs) are characterized by high percent air voids content, and are widely used as pavement surface drainage layers. This paper presents details on the laboratory investigation performed on evaluation of properties of PFC mixes using the Superpave gyratory compactor. It also, provides a brief review of the latest specifications related to standard practices for mix design and the uses of these mixes adopted by various agencies. Major differences were observed in the design gyrations (Ndesign) and the design aggregate gradations. In this study, six gradations (G) were investigated with binder contents (BCs) ranging between 4.0 and 5.0% by mass of the total mix, for various gyration levels (N). The effect of N, G, and BC on the volumetric properties, unaged abrasion loss, permeability, and the permanent deformation characteristics of PFC mixes were investigated. The experimental results were statistically analyzed to identify the major influencing factors and their significance. © 2009 ASCE.Item Laboratory and theoretical evaluation of clogging behaviour of porous friction course mixes(2010) Suresha, S.N.; George, V.; Ravi Shankar, A.U.The clogging of porous friction courses (PFCs) plays a major role in their resulting performance. Clogging occurs due to deposition of external and internal materials, leading to the loss of permeability and drainage characteristics of PFCs. In this study, investigations were conducted to determine the effect of clogging and de-clogging on the permeability of PFC mixes. Tests were conducted to study the effect of three different clogging materials on PFC mixes prepared using four different aggregate gradations. Permeability tests were conducted using the falling-head concept on cylindrical PFC specimens. The influence of the particle size ratios and the effective air voids on the permeability of fresh, clogged and de-clogged PFC specimens was analysed. Experimental results on the permeability observed were compared with those predicted using theoretical models. Although, the theoretical models tend to overestimate the permeability values, statistical analyses indicate good correlations with the observed results.