Browsing by Author "Suvin, P.S."

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A brief review of titanium (Ti)-based bioimplants fabricated using various additive manufacturing methods
(CRC Press, 2024) Praharaj, A.K.; Suvin, P.S.; Bontha, S.
In recent years, a noticeable growth has been observed in the research and development of manufacturing methods for biomedical implants. Extensive research has been conducted for orthopedic and dental implants due to their huge market size worth 4.5 billion dollars. Titanium (Ti) and its alloys are the most widely acknowledged biomaterials used in the production of orthopedic and dental implants due to their intriguing physical and biological properties including higher mechanical strength, excellent corrosion resistance, and biocompatibility. Apart from pure titanium (CP-Ti) and Ti-6Al-4V alloy, β-titanium has recently emerged as one of the important biomaterials for specific orthopedic applications due to its harmless chemical composition and low modulus. Over the years, Ti-based bioimplants were manufactured by conventional machining techniques which were less economical. With the growing demand across the world for the fabrication of customized biomedical implants, researchers were focusing on the development of new approaches and techniques for these implants. Recently, additive manufacturing (AM) has emerged as a potential fabrication method for biomedical implants due to its ability to produce customized products in less time with higher precision and flexibility. In addition, AM-fabricated bioimplants have shown improved osseointegration when compared to conventionally processed implants. In this chapter, various AM methods used for the fabrication of Ti-based implants were summarized with a special focus on the process parameters, microstructure, and related mechanical properties of the end product. Further, the effect of porous structures on the performance of Ti-based bioimplants was highlighted. This study will be helpful in identifying the pros and cons of AM methods in the manufacturing of bioimplants and leads to the advancement of research direction in biomedical sectors. © 2025 selection and editorial matter, Abhilash P M, Kishor Kumar Gajrani and Xichun Luo.
Articulated Robotic Arm for Feeding
(Springer Science and Business Media Deutschland GmbH, 2023) Nair, A.; Rajendran, D.; Jacob, J.C.; Varghese, N.S.; Suvin, P.S.
In todayâ€™s fast-paced world, disabled people are a large minority group, starved of services, mostly ignored by society, and live in isolation, segregation, poverty, charity and even pity. There are numerous forms of disabilities. The disability suffered by most persons includes mental disability, emotional, physical and cognitive. Perhaps the most overlooked effect of a disability that affects the motor functions of the limb is the reliance on other people for the completion of even simple tasks that ordinary people perform on a daily basis, like taking a shower, dressing up, brushing teeth, or even having a meal. This chips away at the self-worth of a disabled person and gnaws away at their confidence. Through our project, we aim to provide a solution to those with compromised motor functions. This project aims to develop a 4 DOF robotic manipulator that is able to map the facial structure of the user, and with a feeding device (spoon/fork) attached to its arm transfers adequate portion of food accurately into the userâ€™s mouth without spillage through smooth motion, by incorporating Image Processing, Manipulator Kinematics and Machine Learning. Â© 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Effect of Heat Treatment on Microstructure and Dry Sliding Wear Behavior of Laser Directed Energy Deposited Inconel 625
(Springer, 2025) Praharaj, A.K.; Chaurasia, J.K.; Suvin, P.S.; Narayanan, J.A.; Paul, C.P.; Balla, V.K.; Chakrapani, S.K.; Bontha, S.
Laser directed energy deposition (LDED) is a promising technology for manufacturing and repair of Inconel 625 (IN625) components used in critical sectors requiring enhanced tribological performance due to harsh operating environments. Hence, the current work focuses on the evaluation of the tribological performance of LDED-built IN625 with the implementation of different heat treatment methods, i.e., solution treatment (ST), direct aging (AG), and solution treatment + aging (ST + AG). A detailed microstructural analysis, hardness, and wear testing were performed for the as-deposited (AD) and heat-treated (HT) samples, and the results were compared. The analysis revealed coarser grains in the case of ST and ST + AG samples, whereas finer grains for AD and AG samples, indicating grain coarsening after solution treatment. Further, the brittle laves phase gets dissolved after ST, whereas the AG and ST + AG samples resulted in the precipitation of metal carbides and strengthening phases. The microhardness of the ST sample (193.2 HV) was lower compared to the AD (211.6 HV) sample, whereas the AG and ST + AG samples exhibited 25.6 and 9.3% higher hardness than the AD sample. Considering tribological performance, the AG sample illustrated a maximum reduction of 61.4% in the coefficient of friction (COF) and 36.5% in wear rate when compared to the AD sample. This could be attributed to the presence of finer grains and strengthening phases. © ASM International 2025.
Effect of Laser Surface Modification on Texture, Roughness, Wettability and Surface Energy of Hastelloy C22, C276 & X
(Trans Tech Publications Ltd, 2024) Suvin, P.S.; Singh, A.; Depu Kumar Patro, B.; Edachery, V.; Kailas, S.V.; Horng, J.H.
Hastelloy is a nickel-chromium-molybdenum-iron-based alloy and a member of the ‘superalloy’ family. Hastelloy has exceptional properties like high strength, wear resistance and hightemperature stress-corrosion resistance. Therefore, Hastelloy is used in gas turbines, power plants, metal injection molding, etc. Many industrial applications are related to the properties of the surface. Wettability is a key surface property that affects applications like lubrication, adhesion, coating, heat conduction, etc. Laser Texturing is an excellent method to modify the surface properties of materials like metal, polymers and ceramic. In the present study, a carbon dioxide laser created unidirectional textures on Hastelloy (C22, C276, X). Different sets of unidirectional textures were formed by changing the laser power and frequency. Various roughness parameters were compared for every laser parameter. In this paper, the effective change in wettability properties of Hastelloy (C22, C276, X) after the Laser texturing process for a range of power and frequency were studied under DI water and glycerol as test fluids. Results show that the contact angle of the test fluid increases as the laser power increases, and the contact angle decreases as the laser frequency increases for all three superalloys. The surface energy of a given set of samples was also measured using the recorded contact angle of DI water and Glycerol by the OWRK equation. Similar trends were found in surface energy for all three Hastelloy. © 2024 Trans Tech Publications Ltd, Switzerland.
Effect of Surface Topography and Roughness on the Wetting Characteristics of an Indigenously Developed Green Cutting Fluid (GCF)
(CRC Press, 2023) Edachery, V.; Ravi, S.; Badiuddin, A.F.; Tomy, A.; Suvin, P.S.; Kailas, S.V.
The production of cutting fluids from petroleum-based products has resulted in significant improvements in the current and rising machining sector. However, the majority of cutting fluids are costly, harmful, and unsustainable mineral base oils. A vital concern lies in their improper disposal, as it can cause pollution of groundwater, as well as pollute agro-based farm products. To counter these hazardous effects, the synthesis of an eco-friendly alternative was crucial. By mixing nontoxic emulsifiers and natural ingredients, a coconut oil-based Green Cutting Fluid (GCF) was created. Many of the defining requirements of commercial formulations are satisfied by GCF while yet being ecologically friendly. This study’s goal is to determine how surface topography and roughness affect the GCF’s ability to wet surfaces made of EN31 steel, titanium alloy Ti6Al4V, and aluminum alloy AA5052. Also, experiments are conducted to determine an optimum concentration of usage of the GCF for the aforementioned surfaces. The findings provide strong, clear proof that the GCF is a practical, long-term replacement for mineral oil-based cutting fluids for its superior wetting qualities and advantages for the environment. © 2024 selection and editorial matter Ravi Kant, Hema Gurung and Shashikant Yadav; individual chapters, the contributors.
Effect of temperature on tribological behavior of L–proline–based green deep eutectic solvents for Ti6Al4V interfaces: A study of novel potential lubricant
(Elsevier Ltd, 2025) Kumar Patro, B.D.; Naik, S.; Suvin, P.S.; Udayakumar, U.; Kreivaitis, R.
This study aims to develop a novel, eco-friendly lubricant engineered to meet antiwear requirements, reduce energy consumption, and improve performance reliability. A series of deep eutectic solvents (DESs) was successfully synthesized using a facile, one-step approach by combining eco-friendly L-Proline with diols and two distinct carboxylic acids as hydrogen bond donors. The resulting DES lubricants exhibit favourable physicochemical properties and excellent lubrication performance. Notably, the L-Proline /Oxalic acid DES demonstrates superior lubrication performance, resulting in a substantial decrease in both friction (?46–78 %) and wear volume (?61–91 %) compared to PEG 200 and choline chloride/urea across all tested temperatures. Furthermore, in-depth analysis of the worn surfaces reveals the formation of a tribo-chemical film derived from L-Proline based DESs, consisting of hydrocarbon (CxHy), oxy metal nitride (Ti-N-O) fragments, along with titanium oxide/hydroxide-rich layer. This film plays a vital role in delivering effective lubrication for titanium alloy surfaces. These findings pave the way for designing eco-friendly, high-performance lubricants for sustainable lubrication practices. © 2025 Elsevier Ltd
Enhanced tribological performance of laser directed energy deposited Inconel 625 achieved through laser surface remelting
(Elsevier B.V., 2024) Praharaj, A.K.; Chaurasia, J.K.; Gurugubelli, R.C.; Bontha, S.; Suvin, P.S.
Inconel 625 (IN625) is an essential material for the manufacture of turbine blades and seals, aircraft ducting systems, engine components, and pressure valves. Laser Directed Energy Deposition (LDED) process has shown the potential to fabricate IN625 parts with superior mechanical properties and higher corrosion resistance when compared to those fabricated using conventional manufacturing techniques. However, the poor surface quality limits the practical application of LDED fabricated parts, especially in sectors that demand high tribological performance. To this end, this study focuses on improving the surface quality and tribological performance of LDED fabricated IN625 components using Laser Surface Remelting (LSR) as a postprocessing operation. The tribological performance was evaluated using a linear reciprocating ball-on-flat wear test setup. The surface roughness, remelting depth (RD), microstructure, hardness, and tribological performance (coefficient of friction and wear rate) of the remelted (RM) samples were compared with that of as-deposited (AD) samples. Microstructural characterization revealed that LSR resulted in grain refinement, reduced dendrite size, and primary dendritic arm spacing (PDAS). Laser scanning speed effects RD, dendrite size and PDAS via its effect on cooling rates. SEM + EDS analysis confirmed the presence of Laves phase in both AD and RM samples. XRD analysis of RM samples showed an increase in the amount of Laves phase. The refinement in microstructural features and the increased amount of Laves phase among the RM samples led to improvement in microhardness when compared to AD samples. Wear test results revealed a reduction in the coefficient of friction (COF) and wear rate after LSR with wear mechanism being either abrasive or delamination. Reduction in the size of dendrites and refinement in grain size are attributed to the enhanced tribological performance after LSR. © 2023 Elsevier B.V.
Enhancing the tribological performance of PEG 200 using oil-miscible deep eutectic solvents as lubricant additives
(Elsevier Ltd, 2025) Kumar Patro, B.D.; Suvin, P.S.
This study investigated a comprehensive assessment of the tribological and anti-corrosion behavior of a novel, halogen-free, and oil-miscible deep eutectic solvent (DES) additive in PEG 200. The DES, referred to as DOA, was synthesized from naturally derived L-Proline and oxalic acid and exhibited good miscibility with PEG 200 due to its polar functional groups. Corrosion tests, including electrochemical and copper strip experiments, confirmed that the DOA/PEG blends maintained consistent anti-corrosion performance. Tribological evaluations revealed that incorporating 3 wt% DOA resulted in a 30 % reduction in the coefficient of friction and a 60.3 % decrease in wear volume compared to PEG 200 alone. ANOVA analysis validated the statistical significance (p < 0.05) of DOA concentration on friction and wear responses, confirming a synergistic effect between DOA and PEG 200. These improvements are attributed to strong interfacial interactions and the formation of a protective tribo-chemical film. Surface characterization identified the presence of hydrocarbons (CxHy), iron oxides, and FeOOH layers, which improved lubrication in the steel–steel contact pair. These findings highlight the potential of DOA as a promising green additive for advancing sustainable lubrication technologies. © 2025 Elsevier Ltd
Evaluation of a comprehensive non-toxic, biodegradable and sustainable cutting fluid developed from coconut oil
(SAGE Publications Ltd, 2021) Suvin, P.S.; Gupta, P.; Horng, J.-H.; Kailas, S.V.
The evolution in development of cutting fluid from petroleum based products have brought about remarkable changes to the present and growing machining industry. Most of the cutting fluids are made of mineral base oils which are toxic, non-biodegradable and unsustainable. A major issue lies in their inappropriate disposal which results in surface water and groundwater contamination and consequently, agricultural products and food contamination. Hence, the objective of this study is to develop an alternative, sustainable, non- toxic and completely bio-degradable cutting fluid to replace the mineral oil based cutting fluid. A Green cutting fluid [GCF] was prepared by combining nontoxic emulsifiers and natural additives. GCF meets many of the characteristic specifications of commercial formulations with the added advantage that it is eco-friendly. Toxicity test for cutting fluids has been carried out using fish toxicity test (OECD -203). The GCF with green additives has an LC50 value ?1064 mg/L. Commercial cutting fluid (CCF) has an LC50 value less than 100 mg/L These tests show that commercial cutting fluids are highly toxic, while the GCF can be considered as non-toxic. Biodegradability test was done using BOD-COD technique and found GCF as biodegradable and CCF as non-biodegradable. The ASTM D4627 corrosion tests infer that the GCF with grade 3 has better anticorrosive characteristics when compared to grade 4 of most CCF samples tested this could be possibly by the effect of natural additives in GCF. Drilling experiments were carried out to evaluate the machining performance of cutting fluids. Results from the drilling tests comparing the axial force/cutting force and torque showed that the performance of the GCF was comparable to that of the CCFs. Nevertheless, GCF formulation with non- toxic emulsifiers and natural additives is a good basis for further development and use of non-toxic tribological products. © IMechE 2020.
Green lubricants in action: a comprehensive performance evaluation of groundnut oil-based cutting fluids in metal machining processes
(Institute of Physics, 2024) Srinivas, M.S.; Kumar, D.; Suvin, P.S.; Kailas, S.V.; Pawar, S.R.; Roy Choudhury, M.
As industries worldwide seek environmentally sustainable solutions, the metalworking sector faces a growing need for eco-friendly alternatives to traditional cutting fluids. This abstract introduces the concept of an innovative approach to cutting fluid technology—the use of groundnut oil as a base material for machining fluids. Derived from peanuts, groundnut oil presents a renewable and biodegradable alternative to petroleum-based counterparts, addressing concerns related to resource depletion and environmental impact. A comprehensive performance evaluation of groundnut oil- based cutting fluid has been carried out by series of critical tests such as separation testing, particle size and stability testing, frictional testing, corrosion testing and drilling testing. The results of these tests collectively contribute to a comprehensive understanding of groundnut oil-based cutting fluids, shedding light on their potential as sustainable and high-performance alternatives in metalworking. The zeta potential for the prepared green cutting fluid has been found to be 49.10 mV. The dimensions of the dispersed particles in a fluid of the cutting fluid have been found as 250-260 nm. The environmentally friendly cutting fluid exhibits favourable outcomes in corrosion resistance, frictional performance, and drilling efficacy during testing. © 2024 The Author(s). Published by IOP Publishing Ltd.
Improving Surface Finish of Laser Additively Manufactured Curvilinear Surfaces Via Electropolishing and Electroless Coating
(American Society of Mechanical Engineers (ASME), 2025) Praharaj, A.K.; Kambikath, N.V.; Suvin, P.S.; Bontha, S.
Laser-directed energy deposition (LDED) is a very useful additive manufacturing technique for repairing and manufacturing complex-shaped parts compared to traditional manufacturing techniques. However, the inadequate surface quality of the LDED fabricated components limits their direct utilization in different sectors. In addition, improving the surface finish of the curvilinear surfaces (useful for cooling channels and fuel nozzles) is also challenging. Hence, the current study focuses on surface modification of LDED fabricated SS 316L hollow cylindrical samples by combining electropolishing and electroless coating. We have performed electropolishing (two different currents, 8 A and 15 A) on the as-deposited (AD) sample with and without the application of the grinding process. The electropolishing reduced the roughness of the AD sample from 3.2 ?m to 0.85 ?m and 0.74 ?m for 8 A and 15 A, respectively. The reduction in roughness was more at a higher current value due to the rapid anodic dissolution of the surface peaks. A further reduction in roughness was observed when grinding was performed before electropolishing. However, grinding resulted in higher material removal from the deposited surfaces and reduction in roughness was also minimal. Hence, only the electropolishing sample was selected for the next step, in which Ni-P electroless coating was performed on the surface to form a protective layer. After electroless coating, the coefficient of friction and wear-rate were reduced by 9.5% and 25.6% compared to the AD sample. Delamination and severe plastic deformation were the major wear mechanisms for the AD sample, whereas abrasion was dominant for the coated sample. The current work proposes a combined surface modification approach of electropolishing and electroless coating for the LDED processed components with curvilinear surfaces. © © 2024 by ASME.
Investigating the Wettability, Rheological, and Tribological Properties of Ammonium-Based Protic Ionic Liquids as Neat Lubricants for Steel–Steel and Steel–Aluminium Contacts
(Multidisciplinary Digital Publishing Institute (MDPI), 2023) Depu Kumar Patro, B.; Suvin, P.S.; Kreivaitis, R.; Gumbyte, M.
This study aims to evaluate the tribological properties of two protic ionic liquids (PILs) under different tribological conditions as a sustainable alternative for mineral oil-based neat lubricants. The synthesis of PILs in this study uses a relatively simple and less expensive method. The Fourier transform infrared (FTIR) spectroscopy results help validate the synthesised PILs’ formation. Further, their physicochemical and tribological properties were investigated. The PILs as neat lubricants were tested on a ball-on-plate reciprocating tribometer using bearing steel–bearing steel and bearing steel–aluminium alloy friction pairs at 30 °C and 80 °C. The results show that the investigated PILs significantly reduced the coefficient of friction and wear. The dodecylamine-based PILs performed better in friction and wear reduction than the other investigated lubricants. The formation of the adsorption layer on the friction pairs was assumed to be the dominant friction and wear reduction mechanism. © 2023 by the authors.
Investigation on high-temperature tribological performance of laser directed energy deposited Inconel 625 for aerospace applications
(Elsevier Ltd, 2025) Praharaj, A.K.; Bontha, S.; Balla, V.K.; Chakrapani, S.K.; Suvin, P.S.
Laser directed energy deposition (LDED) is an emerging technique for fabricating superalloy based aero engine components. Hence, the current work investigates the tribological performance of LDED processed IN625 at room temperature (RT) and high temperature (HT) conditions of 850 °C to replicate the operating environment of aero engine components. The comparison with conventionally processed (CP) sample confirmed that as-deposited (AD) sample showed similar friction behavior to the CP sample but slightly improved wear performance. The COF and wear rate of AD sample reduced significantly at HT compared to RT due to the evolution of stable oxide layer. NiO, Fe2O3, and Cr2O3 were the major phases in oxide layer. The work indicates suitability of LDED to fabricate wear resistant surfaces. © 2024 Elsevier Ltd
Investigation on the tribological performance of protic ionic liquid as an additive in PEG200 for steel–steel contact
(SAGE Publications Ltd, 2025) Depu Kumar Patro, B.D.K.; Suvin, P.S.
Ionic liquids (ILs) offer multifunctional capabilities as lubricant additives. However, many conventional ILs contain moisture-sensitive halogen-based anions that may hydrolyze to form corrosive halogen acids, leading to surface degradation. This study explored halogen-free, amine-based protic ionic liquids (PILs) as additives in polar base oil polyethylene glycol (PEG200). Anti-corrosion tests revealed that incorporating PILs into PEG200 significantly improves corrosion resistance. Lubrication tests performed at various PIL concentrations showed that the blend containing 5wt% PIL exhibited the best performance, reducing the friction coefficient by 26.12% and wear volume by 90.61% compared to neat PEG200. Spectroscopic analysis confirms the formation of a protective tribofilm within the wear tracks, consisting of oxy-organic compounds and metal oxides such as FeOOH, Fe2O3and Fe3O4. This tribofilm minimizes direct contact between sliding surfaces and facilitates effective lubrication. These findings demonstrate the potential of amine-based PILs as efficient and environmentally friendly additives for PEG-based lubricants. © IMechE 2025
Machining of hard materials using textured tool with minimum quantity nano-green cutting fluid
(Elsevier Ltd, 2021) Gajrani, K.K.; Suvin, P.S.; Kailas, S.V.; Pradhan, K.P.; Ravi Sankar, M.R.
Metal cutting causes severe friction and heat generation in the machining zone. Previously, petroleum-based cutting fluids were applied for reducing friction and machining temperature at the machining zone. Nowadays, nano-cutting fluids are preferred owing to their higher thermal conductivity and better lubricating ability. However, during machining of hard materials (hardness, ?50 HRC), the effectiveness of these nano-cutting fluids is limited, as they rarely reach to the cutting edge of cutting tool because of high normal stresses. In this regard, the combination of rake face micro-textured cutting tool with indigenously synthesized nano-green cutting fluids under in-house developed minimum quantity cutting fluid (MQCF) environment is accomplished for hard machining experiments. For comparison, hard machining experiments are also performed under dry machining, green cutting fluid and nano-green cutting fluid (NGCF) with untextured cutting tools. Detailed analysis shows significant improvement in hard machining performance using combination of micro-textured tools with NGCF corresponding to forces, chip-tool interface friction, workpiece surface roughness and chip morphology. It is attributed to better infiltration of NGCF in-between chip-tool interface by virtue of micro-textures present on the cutting tool rake face. Further, the proposed analytical model captures the effect of textures on the tool surface in the same way as reduced contact tools. It is in a good agreement with corresponding experimental cutting forces. © 2021 CIRP
Mechanical and chemical post-treatments for enhancement in tribological performance of laser powder directed energy deposited Inconel 625
(Elsevier B.V., 2025) Praharaj, A.K.; Byregowda, T.; Bontha, S.; Suvin, P.S.
Laser powder-directed energy deposition (LP-DED) technique has shown tremendous potential to fabricate high-performance superalloy parts for real engineering applications. However, certain disadvantages like poor surface quality and incompetent mechanical and wear properties limit its practical usage. Hence, the current work investigates the effect of different post-processing techniques, including laser shock peening (single shot) (LSP1), laser shock peening (three shots) (LSP2), shot peening (high pressure) (SP1), shot peening (low pressure) (SP2), glass bead blasting (GB), sand blasting (SB), and electroless coating (EC) on the surface quality, hardness, and wear resistance of Inconel 625 (IN625) samples fabricated by LP-DED technique. EC sample resulted in the least surface roughness value (0.09 µm), whereas LSP2 sample exhibited the highest increase of 32.4 % in hardness compared to the as-polished (AP) sample. This can be attributed to grain refinement and the plastic deformation in the samples. Further, the wear test confirmed that LSP2 sample resulted in the lowest coefficient of friction (0.6) and wear rate (0.58 × 10-4 mm3/N.m) among the post-processed samples. © 2025 Elsevier B.V.
Micro-tribological Characteristics of Ti6Al4V Alloy Subjected to Shot Blasting Surface Treatment Process
(Springer, 2023) John, A.; Showket, J.; Joseph Babu, K.; Edachery, V.; Suvin, P.S.
Ti6Al4V has remarkable mechanical and physical qualities, but its usage in many applications is constrained by its inferior tribological properties. In this study, Ti6Al4V was shot-blasted with aluminum oxide to enhance the surface hardness and reduce the real area of contact, thereby improving the tribological properties of the metal surface. The data obtained from reciprocating tribometer, optical profilometer, SEM, and EPMA infer considerable improvement in tribological properties and impart information on wear mechanisms attributing to an increase in wear resistance up to 76%. © 2023, The Indian Institute of Metals - IIM.
Microstructure - corrosion performance correlation of laser directed energy deposited Inconel 625
(Elsevier Ltd, 2025) Praharaj, A.K.; Bontha, S.; Balla, V.K.; Chakrapani, S.K.; Suvin, P.S.
The primary objective of the current work is to understand the influence of process parameters on the corrosion performance of laser directed energy deposited Inconel 625 (IN625). In this regard, IN625 bulk samples were deposited using optimized laser power and three different scanning speeds. The as-deposited (AD) samples are named as AD-L, AD-M, and AD-H corresponding to low, medium, and high scanning speeds, respectively. Comprehensive microstructural characterization, microhardness evaluation, and electrochemical corrosion testing (medium: 3.5 wt% NaCl solution) were performed to correlate the process parameters with the microstructural features and corrosion performance. The results revealed that average grain size of the AD-H sample was lowered by 22.8 % and 19 %, respectively than the AD-L and AD-M samples, resulting in an enhancement of 8.4 % and 3.3 % in microhardness. Electrochemical corrosion tests indicated that AD-H sample possessed a higher corrosion potential (Ecorr) and a lower corrosion current density (Icorr) when compared to other samples, confirming the corrosion resistance of the samples in the order of AD-H > AD-M > AD-L. The higher scanning speed resulted in finer grains, high dislocation density, and lowered volume fraction of secondary phases, which are attributed to superior corrosion resistance of the AD-H sample. Surface analysis of the corroded samples suggested a greater susceptibility to localized corrosion over pitting corrosion. The current work provides valuable insights to the correlation between process parameters, microstructure, and corrosion performance of LDED fabricated IN625, confirming notable influence of scanning speed on the corrosion behavior. © 2025 Elsevier B.V.
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 Î¸ between the solidâ€“liquid surface and the vapour-liquid interface. Wettability responses from the roughened surfaces in the range of 0.06â€“2.1 Âµm 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. Â© 2022