Faculty Publications
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Item Examining the Influence of StackinSequence on the Mechanical Properties of Hybrid Abaca-Jute Vinyl Ester Composites(Springer Nature, 2024) Ramesh, S.; Maruthi Prashanth, B.H.; Anne, G.; Naik, G.M.; Reddy, R.; Jagadeesh, C.; Sharma, P.; Prashanth Pai, M.This research looked on the impacts of layer arrange-ment on inter-laminar shear strength (ILSS), tensile, flexural, and impact capabilities of hybrid composite developed from 25% abaca and 25% jute fabrics reinforced 50% vinyl ester. Furthermore, the samples frac-tured under the tensile load were examined using SEM images. Utilizing a hot press process, these hybrid laminates were fabricated and sample preparation and testing were done as per ASTM criteria. The findings demonstrate that among Abaca-Jute-Abaca-Jute (AJAJ), Abaca-Jute-Abaca (AJJA), and Jute-Abaca-Abaca-Jute (JAAJ) vinyl ester composites, the Abaca-Jute-Jute-Abaca (AJJA) composites showed higher tensile modulus and strength by 23–33%, the flexural modulus and strength by 3–22%, the impact behavior, and ILSS strength by 11–33%. These benefits could be attributed to the presence of abaca fiber on the exterior of lami-nates. Fractography studies revealed that the fiber-resin bonding was superior. AJJA composites were found to be stronger than commonly used plastics in automobile interiors, making them a promising alternative. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.Item Microstructural and mechanical characterisation of Al-Zn-Mg-Cu alloy processed by multi-directional cryo-forging(Elsevier Ltd, 2021) Ramesh, S.; Anne, G.; Naik, G.M.; Jagadeesh, C.; Shivananda Nayaka, H.S.Aim of the present investigation is to study the microstructural and mechanical properties of Al-Zn-Mg-Cu alloy before and after multi-direction forging (MDF) at cryogenic condition up to 3 cycles. Microstructure evolution of specimen was examined using optical microscope and orientation imaging microscopy as well as X-ray diffraction. Mechanical properties were measured by tensile test and Vickers micro hardness. Microstructural investigation shows that after 3 cycle of MDF average grain size was reduced to 8 μm with low angle grain boundaries (LAGBs) and high dislocation density. Mechanical examination displays an improvement in hardness, yield strength and ultimate tensile strength is due to increases in grain boundaries and strain hardening effect. After 3 cycles of MDF process with cumulative strain ςΔϵ = 3.64 led to the formation of fine grain structure, and microhardness were observed to be 168 HV. © 2021 Elsevier Ltd. All rights reserved.Item Influence of Ball Burnishing Process on Equal Channel Angular Pressed Mg-Zn-Si Alloy on the Evolution of Microstructure and Corrosion Properties(Springer Science and Business Media B.V., 2021) Ramesh, S.; Anne, G.; Kumar, G.; Jagadeesh, C.; Shivananda Nayaka, H.In the present study, Mg-4Zn-1Si alloy was subjected to equal channel angular pressing (ECAP) up to 4 passes at 300 °C, followed by ball burnishing using 0.3 mm depth of press, 300 mm/min feed and 1 pass successfully. The effect of ECAP and ECAP + ball burnishing process on microstructure, mechanical properties (tensile and hardness) and corrosion behavior was systematically investigated. After 4 pass ECAP, initial coarse grains (210 ?m) were refined and average grain size is 6 ?m and after ball burnishing, the grain size is found to be 3.3 ?m. Microstructure evolution is discussed using optical images, scanning electron microscope images and transmission electron microscope images. For ECAP samples, maximum strength and hardness was recorded at 3 pass. Both strength and hardness decreased for 4 pass ECAP processed samples, even though grain size decreased, this is because of texture modification in the material. ECAP 4 pass + ball burnished samples exhibited 48.5% enhancement of microhardness as compared to 4 pass ECAP samples. Corrosion resistance of the samples decreased with increase in the number of ECAP passes, this is due to strain-induced grain refinement with more crystalline defects in samples. Combined process of ECAP and ball burnishing effectively reduces the Icorr and this consequently reduces corrosion rate of the Mg–4Zn-1Si alloy. © 2020, Springer Nature B.V.Item Effect of Equal Channel Angular Pressing on Properties Evaluation of Biodegradable Mg-Zn-Mn Alloy(Springer Science and Business Media Deutschland GmbH, 2021) Ramesh, S.; Kumar, G.; Jagadeesh, C.; Anne, G.; Shivananda Nayaka, H.Equal channel angular pressing (ECAP) was used to process Mg-4Zn-1Mn alloy at 300 °C using route Bc up to 4 pass with a cumulative strain of 3.2. Optical microscope (OM), microstructures results shows homogenized sample grain size was 260 µm, after 4 pass ECAP grain size was decreased to 6 µm. Electron back-scattered diffraction (EBSD) shows the misorientation angle converted from low-angle grain boundaries (LAGB) to high-angle grain boundaries (HAGB). Dislocation density and fine grains were observed from transmission electron microscope (TEM) images. Strength has been increased from 156 to 218 MPa and hardness increased to 68 Hv after 4 pass of ECAP. Fractography analysis revealed that dimple size decreases as ECAP passes increased. XRD analysis shows the peak broadening and intensity variation, because of grain refinement. The corrosion behavior of the homogenized and ECAP-processed samples were investigated by electrochemical tests using simulated body fluids (SBF) at 37 ± 1 °C. The lower corrosion resistance of ECAP-processed Mg-4Zn-1Mn alloy attributed to the strain-induced crystalline defects, subgrain boundaries and high-density dislocations. Enhanced strength and ductility combined with lower corrosion resistance of ECAP-processed Mg-4Zn-1Mn has greater potentials for biomedical implants. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.Item Effect of Multi-directional Forging on the Evolution of Microstructural and Mechanical Properties of Lightweight Al-Cu-Li Alloy AA2050(Springer, 2023) Jagadeesh, C.; Shivananda Nayaka, H.S.; Ramesh, S.; Praveen, T.R.Microstructural evolution and the mechanical properties of recently developed lightweight AA2050 Al-Cu-Li alloy have been presented. A processing route of multi-directional forging (MDF) at 170 °C followed by artificial aging at 150 °C was employed. Systematic EBSD analysis revealed significant grain refinement with grain size reducing from 74.3 ± 12 to 22.1 ± 2.8 µm after 12 passes of MDF. Transformation of deformation bands into subgrains with dynamic recrystallization has led to grain refinement. TEM results show the presence of large dislocation clusters and deformation bands in MDF processed samples with a large number of fine precipitates in peak aged MDF processed samples. XRD analysis shows variation in peak intensities and occurrence of peak shifts due to induced lattice strain upon MDF. A substantial increase in microhardness and strength was observed with a minor trade-off with ductility after 12th MDF pass. Further, enhancement in strengths and microhardness were observed in post-MDF aged samples. Experimental results show the combined effect of strain hardening, grain size reduction, and precipitate hardening which influence the material strength. A combination of MDF and artificial aging has shown great potential to enhance the strength and ductility of AA2050. © 2023, ASM International.Item Enhancing surface characteristics of Mg-Zn-Sr alloy through cryo-ball burnishing; modeling and experimentation(Korean Society of Mechanical Engineers, 2024) Kudva, S.A.; Anne, G.; Ramesh, S.; Sharma, P.; Jagadeesh, C.; Ritti, L.; Naik, G.M.; Divya Deepak, G.D.In this investigation, the impact of the cryo-ball burnishing process on both the mechanical and corrosion properties of the Mg-4Zn-1Sr alloy was systematically explored. To better understand the plastic deformation occurring in Mg-4Zn-1Sr during cryo-burnishing, a finite element analysis (FEA) model was developed. The microstructure of cryo-ball burnished samples underwent characterization through scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD), and surface properties were assessed using atomic force microscopy (AFM). Additionally, electrochemical impedance spectroscopy and potentiodynamic polarization tests were conducted in a simulated body fluid using an electrochemical workstation. Experimental findings revealed significant grain refinement and the presence of residual dislocations during the cryo-burnishing process, as evident in TEM analysis. XRD analysis indicated the presence of Mg, Mg17Sr2 and SrZn2 phases, with observable peak broadening in the cryo-burnished samples, attributed to structural refinement and lattice strain incorporation. Microhardness values increased with greater depth of press, with the DFN 1071 sample displaying a hardness of 80 ± 4 Hv (Ra = 1.853 µm), marking a 54 % improvement compared to the homogenized sample. The enhanced corrosion resistance of the Mg-4Zn-1Sr alloy due to cryo-burnishing is attributed to the combined effects of grain refinement, residual dislocations, and intermetallic phases. © The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany, part of Springer Nature 2024.Item On the microstructure, texture and electrochemical properties of severely deformed and artificially aged lightweight AA2050 Al-Cu-Li alloy(Institute of Physics, 2024) Jagadeesh, C.; Shivananda Nayaka, H.; Sekar, P.; Ramesh, S.; Anne, G.Lightweight 3rd generation Al-Cu-Li alloy AA2050 was severely deformed via Multi Axial Forging (MAF) at 170 °C followed by artificial aging at 150 °C. Effect of MAF and post MAF aging on microstructure and precipitation was investigated using transmission electron microscopy (TEM). Formation of deformation bands and large dislocation cells were evident on MAF processed samples. Post MAF peak aging resulted in the distribution of fine T1 precipitates in grain interiors with reduction in grain boundary precipitation. Bulk texture studies reveal the formation of strong Goss and S texture components upon MAF processing. Further, low temperature artificial aging doesn’t exhibit significant changes in texture characteristics, either in terms of texture intensities or texture components. Polarization studies showed that peak aged samples exhibited better corrosion resistance compared to un-aged samples. Overall, 12 pass MAF processed and peak aged samples showed higher corrosion resistance. Further, corrosion surface morphologies examination revealed the change in corrosion mechanisms with thermomechanical treatments. Improved corrosion resistance after MAF and peak aging widens the requirements in aerospace and aircraft applications for such engineering alloys. © 2024 The Author(s). Published by IOP Publishing Ltd.Item Impact of ply stacking sequence on the mechanical response of hybrid Jute-Banana fiber phenoplast composites(Institute of Physics, 2024) Maruthi Prashanth, B.H.; Ramesh, S.; Shivakumar Gouda, P.S.S.; Naik, G.M.; Sharma, P.; Jagadeesh, C.; Mahantesh, M.M.; Anne, G.Natural fiber composites are increasingly gaining popularity as a cost-effective and environmentally friendly alternative to synthetic fibers. Incorporating a variety of fibers enhances mechanical properties. The arrangement of fibers plays a crucial role in determining the mechanical characteristics of laminate composites. Therefore, the primary objective of this study is to investigate how the stacking order of jute (J) and banana (B) fibers affects the mechanical behaviour of composites made from phenolic resins. Four different fiber mat stacking sequences (J/B/B/J, B/J/J/B, J/B/J/B, and J/J/B/B) were used for developing the eco-fiber composites using the heat-press technique. Several mechanical parameters were assessed, including tensile strength, flexural strength, impact strength, and inter-laminar shear strength (ILSS). The experimental results indicated that the JBBJ composite exhibits superior tensile strength (46.65 MPa) and modulus (993 MPa) compared to the other composites due to the presence of high-strength jute fibers on the surface. Additionally, the flexural strength of the JBBJ composite (87.24 MPa) was found to be noteworthy. It was observed that the impact strength of jute fibers surpasses that of banana fibers. Consequently, the JBBJ composite demonstrates higher values for energy absorption (0.482 J) and impact strength (120 J m−1) compared to the other composites tested. Moreover, the JBBJ composite displays higher inter-laminar shear strength and hardness values compared to BJJB, JBJB, and JJBB by 30%, 35%, and 43%, respectively. Scanning electron microscope microphotographs reveal strong correlational fracture failure mechanisms, indicative of improved mechanical properties in the JBBJ composite. Based on the experimental results, it is evident that the JBBJ composite can be utilized in lightweight applications. © 2024 The Author(s). Published by IOP Publishing Ltd.Item Reciprocating wear behavior of multi-directionally forged and aged Al-Cu-Li alloy(Institute of Physics, 2024) Jagadeesh, C.; Shivananda Nayaka, H.; Ramesh, S.; Anne, G.Al-Cu-Li alloys have drawn attention because of their decreased density, which is a result of the growing need for lightweight material systems in aerospace and aircraft applications. The alloy was subjected to multi-directional forging (MDF) and post-MDF artificial aging. Reciprocating sliding wear tests were conducted to investigate the effects of these processes on wear properties under different load conditions. After MDF, a decrease in wear resistance was noticed, on the other hand, 12 pass MDF treated samples showed improved wear resistance upon aging treatment. Wear scars and counter ball surfaces were examined using scanning electron microscope (SEM) to understand the wear mechanism and wear mode. The findings demonstrated that, at lower loads, adhesion and abrasion were the main wear processes; at greater loads, delamination, adhesion, and abrasion were clearly visible. The study revealed that the MDF and subsequent aging have a substantial effect on the wear behavior of Al-Cu-Li alloy and is an effective thermomechanical processing route to enhance wear resistance. © 2024 The Author(s). Published by IOP Publishing LtdItem Effect of addition of Ce and accumulative roll bonding on structure-property of the Mg-Ce-Al hybrid composite and its prediction and comparison using artificial neural network (ANN) approach(Institute of Physics, 2024) Anne, G.; Bhat, N.; Vishwanatha, H.M.; Ramesh, S.; Maruthi Prashanth, B.H.; Sharma, P.; Aditya Kudva, S.; Jagadeesh, C.; Nanjappa, Y.Light alloys play a crucial role in realizing the national strategy for energy conservation and emission reduction, as well as promoting the upgrading of manufacturing industries. Mg/Al composite laminates combine the corrosion resistance and ductility of aluminium alloy with the lightweight characteristics of magnesium alloy. The addition of Ce (rare earth elements) can improve the mechanical properties of magnesium via grain refinement and improve the ductility of the hybrid composites. In the present work, an investigation on addition of Ce into the Mg/Al matrix through Accumulative Roll Bonding (ARB) has been presented. The Mg/Ce/Al hybrid composite consists of Mg-4%Zn alloy and Al 1100 alloy with 0.2% Ce particles added between the dissimilar layers. The changes occurred in the evaluation of microstructure, corrosion and mechanical properties of the Mg/Ce/Al hybrid composite as a result of deformation process and also the addition of Ce have been explicated. The ARB parameters: temperature, rolling speed, percentage reduction, and aging time, have been studied. An increase of about 2.36 times in strength and hardness of the hybrid composite, has been reported. Further, the structure-property relations in the Mg/Ce/Al hybrid composites were aslo predict and compare using machine learning models: Decision Tree and Multi-Layer Perceptron (MLP) models. © 2024 The Author(s). Published by IOP Publishing Ltd.