Browsing by Author "Ramesh, S."

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A study on dimensional analysis modeling of crater size during wire electrical discharge turning process by using Buckingham Pi theorem
(Elsevier Ltd, 2022) Naik, G.M.; Hipparagi, M.A.; Bellubbi, S.; Roy, A.; Anjan, B.N.; Ramesh, S.; Narendranath, S.
The investigation on material removal by thermal erosion of discrete spark and vaporization in wire electrical discharge turning process was made to understand the crater size variation on turned components. In this study the modelling is done to establish the relationship between dependent and independent variables through Buckingham's Pi-theorem, to predict the variations of crater diameter depending on physical and thermal properties, subsequently the dimensional model was validated by conducting experiments on wire-electrical discharge turning process for two distinct density variant materials such as Aluminium 6061 and INCONEL 718 super alloys. The density, enthalpy of vaporization, radius of spark, specific heat and other quantities effect on crater diameter have been discussed in this research paper. Â© 2022
An ontology aided gso optimized extreme learning for situation recognition in coal mining environment
(Institute of Advanced Scientific Research, Inc. dheep.infotel@gmail.com, 2017) Ramesh, S.; Vittal, K.P.
A wireless sensor network (WSN) is a wireless network comprising of spatially distributed autonomous devices utilizing sensors for monitoring the physical or environmental situations. WSN has been applied in many fields such as healthcare monitoring, coal mine safety monitoring system and also in military. To detect the seismic activities in the coal mining environment, several techniques such as Bord and Pillar model, Bayesian Decision method etc., were introduced and carried out. In this paper, we have proposed anOntology aided Fuzzy Cognitive Maps (FCM) based feature correlation extraction technique for the multi attribute sensor data.Further, the Galactic Swarm Optimization (GSO) algorithm optimized Extreme Learning Machine (ELM) is used. The correlation extraction technique gives the better solution to determine the similarity between the semantically related heterogeneous sensor reading data and resolves the semantic ambiguity problem of heterogeneous sensors present in the coal mining Environment. © 2017, Institute of Advanced Scientific Research, Inc. All rights reserved.
Combined effect of multidirectional forging and heat treatment on erosion and corrosion behaviour of the Mg-Zn-Mn alloys
(Korean Society of Mechanical Engineers, 2024) Anne, G.; Hegde, A.; Kudva, S.A.; Sharma, P.; Kumar, P.; Matapati, M.; Ramesh, S.; Sharma, S.S.
Multidirectional forging (MDF) was successfully applied to the Mg-4Zn-1Mn alloy for five passes at 300 °C. The grain size of 5 pass MDF processed samples reached 18 ± 3 µm from 256 ± 6 µm, and ?-Mg, MgZn2 and MnZn13 peaks were observed. Further MDF processed samples were solution treated (ST) at 300 °C for 2 h and quenched in SAE 20W40 oil and followed by artificial ageing (A) at 170 °C for four different timings including 1.5 h, 2 h, 2.5 h and 3.5 h respectively. The peak hardness of 219 Hv (5 pass MDF + H sample) was found in 2h artificial ageing which is 3.1 times higher compared to counterpart homogenised samples. Improvement of mechanical properties was attributed to smaller grain size and precipitation strengthening as well as distribution of the secondary phases. The combined effect of MDF and heat treatment was analysed using solid particle erosion tests at 30° and 90° impact angles using alumina. It was observed that higher impact angle (90°) had more erosion rate in all conditions and 5 pass MDF + H samples exhibited better erosion (0.0001 mg/g) due to higher hardness. On the other hand, polarisation and electrochemical impedance spectroscopy measurements were used to assess the alloys’ corrosion behaviour. The 3 pass MDF + H sample was found to have a corrosion rate of 0.0235 mm/y, which is two times lower than the counterpart 3 pass MDF processed samples and sixteen times lower than the homogenised sample (0.3838 mm/y). This was primarily due to the secondary phases’ better distribution and smaller grain size. © The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany, part of Springer Nature 2024.
Development, Characterization, Mechanical and Corrosion Behaviour Investigation of Multi-direction Forged Mgâ€“Zn Alloy
(Springer International Publishing, 2019) Anne, G.; Ramesh, S.; Kumar, G.; Sahu, S.; Ramesh, M.R.; Shivananda Nayaka, H.; Arya, S.
In the present study, homogenized Mgâˆ’4%Zn (wt%) alloy was exposed to multi-direction forging (MDF) at 280 Â°C up to 5 passes successfully. Microstructural evolution, mechanical properties and corrosion behavior of the MDF-processed Mgâˆ’4%Zn alloy was investigated using different characterization techniques. Five passes of MDF (cumulative strain, Î£Î”Îµ = 3.45) led to the formation of ultrafine grain structure (grain size ~2.3Ã‚Â Î¼m) with high angle grain boundaries (HAGBs) and high dislocation density. Corresponding ultimate tensile strength (UTS) and microhardness were observed to be 228Ã‚Â MPa and 88 Hv. Potentiodynamic polarization test results exhibited higher corrosion resistance (0.38Ã‚Â mm/y) in comparison with that of homogenized condition (1.33Ã‚Â mm/y). Â© 2019, The Minerals, Metals & Materials Society.
Development, Characterization, Mechanical and Corrosion Behaviour Investigation of Multi-direction Forged Mg�Zn Alloy
(2019) Anne, G.; Ramesh, S.; Kumar, G.; Sahu, S.; Ramesh, M.R.; Shivananda, Nayaka, H.; Arya, S.
In the present study, homogenized Mg?4%Zn (wt%) alloy was exposed to multi-direction forging (MDF) at 280 �C up to 5 passes successfully. Microstructural evolution, mechanical properties and corrosion behavior of the MDF-processed Mg?4%Zn alloy was investigated using different characterization techniques. Five passes of MDF (cumulative strain, ??? = 3.45) led to the formation of ultrafine grain structure (grain size ~2.3 ?m) with high angle grain boundaries (HAGBs) and high dislocation density. Corresponding ultimate tensile strength (UTS) and microhardness were observed to be 228 MPa and 88 Hv. Potentiodynamic polarization test results exhibited higher corrosion resistance (0.38 mm/y) in comparison with that of homogenized condition (1.33 mm/y). � 2019, The Minerals, Metals & Materials Society.
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.
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.
Effect of Mechanical properties on Multi Axially Forged LM4 Aluminium Alloy
(Elsevier Ltd, 2020) Sajjan, S.S.; Kulkarni, M.V.; Ramesh, S.; Sharath, P.C.; Kumar, V.; Rajole, S.
Commercially available LM4 Aluminum alloy was subjected through Severe Plastic Deformation (SPD) method by Multi-Axial Forging Process (MAF) in ambient temperature. In this process, the material was processed successfully up to 5 Passes and mechanical properties such as tensile strength, compression strength and hardness of the as received and processed samples at ambient temperature were evaluated. The MAF processed sample result showed that the ultimate strength, percentage elongation and compression strength improved by 55 MPa, 3.75% and 162 MPa respectively as compared with the unprocessed sample. Hardness also increased with the increase in the number of passes. In the case of microstructure, grain size reduced from 110 Î¼m to 8 Î¼m after subjecting the sample to MAF. Fractography explains the nature of the fracture from received to processed samples by decreasing the size of the dimple and the type of fracture observed was ductile in nature. Improvement in strength and hardness of processed samples was observed due to the grain refinement and high amount of density dislocation in the material during MAF. Â© 2018 Elsevier Ltd.
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.
Effect of multiaxial cryoforging on microstructure and mechanical properties of a Cu-Ti Alloy
(Institute of Physics Publishing helen.craven@iop.org, 2019) Ramesh, S.; Shivananda Nayaka, H.S.; Gopi, K.R.; Sahu, S.
Cu-Ti alloy, processed by multiaxial forging (MAF) at cryogenic temperature with a cumulative strain up to 1.64, was investigated for microstructure and mechanical properties. The deformed microstructures were analyzed using optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The average grain size of 2 ?m was achieved in the deformed sample after 3 cycles of MAF. TEM studies indicated that the shear bands width of the deformed sample after 3 cycles reduced to 1 ?m. Tests for mechanical properties indicated an increase in tensile strength and hardness and it was found to be correlated with an increase in dislocation density and grain boundary strengthening mechanism. Ultimate tensile strength (UTS) of 390 MPa, 480 MPa, and 590 MPa was observed in MAF processed samples after 1, 2, and 3 cycles, respectively. Hardness increased from 65 Hv (as-received) to 240 Hv after 3 cycles of MAF. Fractography analysis showed that, with an increase in number of MAF cycles, dimple size reduced up to 1 cycle and percentage elongation increased after 2 cycles of MAF. © 2018 IOP Publishing Ltd.
Effect of multiaxial cryoforging on wear properties of cu-1.5%ti alloy
(2019) Ramesh, S.; Shivananda, Nayaka, H.
Copper-Titanium alloy was subjected to multi axial forging (MAF) at cryogenic temperature. Microstructure evolution was observed using optical microscope (OM). After 9 pass of MAF, grain size reduced to 2 �m. As number of MAF pass increases, hardness of the sample increased, due to strain hardening effect. Dry sliding wear test was performed on as-received and MAF processed samples using pin on disc wear machine. Tests were performed at 30 N and 40 N loads at 3 m/s constant speed and at 1000 m and 2000 m, sliding distance. Scanning Electron Microscope (SEM) and EDS was used to analyze the worn-out surface of the specimen. Wear mass loss of MAF processed sample reduced, with increased number of MAF passes. Frictional Coefficient (COF) reduced with increase in MAF passes and improved with increase in load, because of increase in contact area between sample and disc. � 2019 Trans Tech Publications Ltd, Switzerland.
Effect of multiaxial cryoforging on wear properties of cu-1.5%ti alloy
(Trans Tech Publications Ltd ttp@transtec.ch, 2019) Ramesh, S.; Shivananda Nayaka, H.
Copper-Titanium alloy was subjected to multi axial forging (MAF) at cryogenic temperature. Microstructure evolution was observed using optical microscope (OM). After 9 pass of MAF, grain size reduced to 2 Âµm. As number of MAF pass increases, hardness of the sample increased, due to strain hardening effect. Dry sliding wear test was performed on as-received and MAF processed samples using pin on disc wear machine. Tests were performed at 30 N and 40 N loads at 3 m/s constant speed and at 1000 m and 2000 m, sliding distance. Scanning Electron Microscope (SEM) and EDS was used to analyze the worn-out surface of the specimen. Wear mass loss of MAF processed sample reduced, with increased number of MAF passes. Frictional Coefficient (COF) reduced with increase in MAF passes and improved with increase in load, because of increase in contact area between sample and disc. Â© 2019 Trans Tech Publications Ltd, Switzerland.
Effect of Rolling Reduction on Microstructure and Mechanical Properties Cu-3%Ti Alloy
(Pleiades journals, 2019) Singh, P.; Ramesh, S.; Anne, G.; Shivananda Nayaka, H.
Cu-3%Ti alloy is cold rolled with different reduction ratios and the microstructures and mechanical properties are compared with that of as-cast Cu-3%Ti alloy. Microstructure was analyzed using optical microscope and scanning electron microscope. Optical microscopy revealed significant grain refinement that occurred during the rolling process. Tensile test results indicate that the UTS is increased by a significant amount up to 80% rolling reduction. A significant amount of tensile strength increased up to 812 MPa is about 1.69 times that of the cast Cu-3%Ti alloy. Hardness of the rolled Cu-3%Ti increased as % reduction increased. Dimples were revealed on the fracture surface of the rolled Cu-3%Ti specimens indicating a ductile nature of the fracture. © 2019, Springer Nature Singapore Pte Ltd.
Effects of combined multiaxial forging and rolling process on microstructure, mechanical properties and corrosion behavior of a Cu-Ti alloys
(Institute of Physics Publishing helen.craven@iop.org, 2019) Ramesh, S.; Anne, G.; Shivananda Nayaka, H.; Sahu, S.; Arya, S.
Combined multiaxial forging (MAF) and rolling was performed on Cu-3% Ti (wt%) alloy at room temperature with emphasis on microstructural evolution, improvement in mechanical properties, and corrosion resistance. Microstructural changes were confirmed from various characterization techniques, and co-related with mechanical properties. TEM analysis revealed high shear band density in the 3 pass MAF + 90% rolled sample appearing due to high strain. EBSD analysis revealed transformation to low angle grain boundaries from high angle grain boundaries. Maximum microhardness and UTS reached to 340 HV and 960 MPa, respectively in the processed samples. Significant grain refinement was observed in MAF processed Cu-3%Ti alloy, and after combined MAF + rolling, higher dislocation density and refinement of shear bands were observed. In addition, potentio-dynamic polarization test was used to study the corrosion behavior of the alloy. Scanning electron microscope (SEM) was used to analyze the corroded surface morphology. © 2019 IOP Publishing Ltd.
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.
Enhancing wear resistance of AZ61 alloy through friction stir processing: experimental study and prediction model
(Institute of Physics, 2024) Anne, G.; Ramesh, S.; Sharma, P.; Maruthi Prashanth, B.H.; Aditya Kudva, S.; Kumar, P.; Sahu, S.; Bhat, N.
In this study, friction stir processing (FSP) is proposed for the treatment of AZ61 alloy, and an artificial neural network is built to predict and compare the experimental wear results. The effects of different processing parameters, including spindle speed (800-1200 rpm), traveling speed (5-15 mm min−1), and depth of press (0.8-1.2 mm) on the microstructural evolution, mechanical properties, and wear behavior are investigated. Microstructural analysis reveals a grain size of 14 ± 2 μm for the FSP1 sample, with observed shifting of x-ray diffraction (XRD) peaks, indicative of texture development. Increasing spindle and traveling speeds increase the surface roughness, as observed by average roughness (Ra) values of 68.4 nm for a rotational speed of 800 rpm, traveling speed of 5 mm min−1, and shoulder depth of 0.8 mm (FSP1) and 116.3 nm for rotational speed of 1200 rpm, traveling speed of 15 mm min−1, and shoulder depth of 1 mm (FSP9). Microhardness values increase to 113.36 Hv for FSP1 and 79. 51 Hv for FSP9 compared to 65.92 Hv for the base material (BM) sample. The decrement in hardness from FSP1 to FSP9 can be attributed to increased heat input, resulting in coarse microstructure. Wear results show that FSP1 exhibits the lowest weight loss (0.003 g) and coefficient of friction (COF) (0.28) compared to other FSP conditions and BM samples (weight loss of 0.022 g and COF of 0.68). This work demonstrates the efficacy of friction stir processing in enhancing the wear resistance of magnesium alloys. © 2024 The Author(s). Published by IOP Publishing Ltd.
Evaluation of microstructure and mechanical properties of multi axial forged lm2 aluminum alloy
(2019) Sajjan, S.S.; Kulkarni, M.V.; Ramesh, S.; Sharath, P.C.; Sangamesh, R.; Kumar, A.; Rajesh, R.
Light metal Al alloys are presently used in aerospace and industrial applications. Hence, in the present study choice of material will be LM2 aluminum alloy and processed by multi-axial forging (MAF) technique at ambient temperature for different number of passes with an equivalent strain of 0.18, 0.36 and 0.54. Microstructural analysis was carried out on unprocessed and processed samples with scanning electron microscopy (SEM). As the number of MAF pass increases the average grain size was reduced because of plastic deformation by plane strain condition. Mechanical properties like Vickers hardness (VHN), tensile and compression test were carried out. Ultimate tensile strength (UTS) was increased after each pass of MAF due to strain hardening effect. After 3 MAF passes the compression strength was reached to maximum of 495 MPa as compared to as received sample 315 MPa and hardness, increased to 81 VHN as compared to 55 VHN for the received samples. The fractography analysis was explained using SEM images. As the number of passes increases dimple size reduces as compared to as received samples and which will be revealing the ductile mode of fracture. � 2019 Trans Tech Publications Ltd, Switzerland.
Evaluation of microstructure and mechanical properties of multi axial forged lm2 aluminum alloy
(Trans Tech Publications Ltd ttp@transtec.ch, 2019) Sajjan, S.S.; Kulkarni, M.V.; Ramesh, S.; Sharath, P.C.; Sangamesh, R.; Kumar, A.; Rajesh, R.
Light metal Al alloys are presently used in aerospace and industrial applications. Hence, in the present study choice of material will be LM2 aluminum alloy and processed by multi-axial forging (MAF) technique at ambient temperature for different number of passes with an equivalent strain of 0.18, 0.36 and 0.54. Microstructural analysis was carried out on unprocessed and processed samples with scanning electron microscopy (SEM). As the number of MAF pass increases the average grain size was reduced because of plastic deformation by plane strain condition. Mechanical properties like Vickers hardness (VHN), tensile and compression test were carried out. Ultimate tensile strength (UTS) was increased after each pass of MAF due to strain hardening effect. After 3 MAF passes the compression strength was reached to maximum of 495 MPa as compared to as received sample 315 MPa and hardness, increased to 81 VHN as compared to 55 VHN for the received samples. The fractography analysis was explained using SEM images. As the number of passes increases dimple size reduces as compared to as received samples and which will be revealing the ductile mode of fracture. Â© 2019 Trans Tech Publications Ltd, Switzerland.
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.
High-pressure torsion of biodegradable Mg?Zn?Mn alloy and investigate mechanical and corrosion behaviour
(Nature Research, 2025) Kumar, P.; Anne, G.; Ramesh, S.; Kudva, S.A.; Ramesh, M.R.; Doddamani, M.; Prabhu, A.; Sahu, S.
Considering their biodegradability in physiological environments and similar elastic modulus to natural bone, magnesium alloys have generated a lot of interest as biodegradable implant materials. Their poor corrosion resistance is primarily a result of the inhomogeneous distribution of their second phase, which limits their clinical application. High pressure torsion (HPT) one of the severe plastic deformation techniques which provides an opportunity to process materials with low formability such as magnesium at room temperature. The present study HPT is conducted for Mg-Zn-Mn alloy up to ten revolutions at room temperature. Optical, scanning, and transmission electron microscopes were used to examine the microstructures of base material (BM) and ten revolution HPT samples. Significant microhardness improvement was observed in HPT N10 samples (222 Hv) as compared to BM samples (68 Hv). It was determined that the improvement in microhardness was primarily due to dislocation strengthening, fine grain strengthening, and second phase strengthening. Potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) were used in a simulated body fluid (SBF) solution to assess the corrosion behaviour. When compared to the BM sample (0.0243 mm/y), the corrosion resistance of the HPT N10 sample (0.0012 mm/y) increased significantly. This was mostly due to the smaller grain size and uniform dispersion of the secondary phases, which result in a uniform corrosion. Further, obtained data from the cytotoxicity assay carried out using the MTT method indicated the compatibility of the Mg-Zn-Mn alloy on MG-63 osteoblast-like cells, further substantiating its safety on the bone cells. © The Author(s) 2025.