Faculty Publications
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Item Surface modification of multi-directional forged biodegradable Mg-Zn alloy by ball burnishing process: Modeling and analysis using deep neural network(Elsevier Ltd, 2021) Ramesh, S.; Anne, G.; Bhat, N.; Aithal, G.; Shivananda Nayaka, H.; Arya, S.This research investigates the feasibility of improving surface integrity of the Mg-2%Zn alloy via a novel combined process of multidirectional forging (MDF) with ball burnishing technique. Mg-2%Zn alloy was subjected to multidirectional forging up to 5 passes at 280 °C and same sample is ball burnished with depth of press of 0.3 mm, feed of 300 mm/min and force of 250 N for 1 pass. Microstructure (optical and transmission electron microscope), phases (X ray diffraction), roughness (atomic force microscope) and mechanical properties (microhardness and tensile) were analyzed for cast, MDF processed and MDF + ball burnished samples. The study also defines a new reliability simulation framework to predict the roughness and hardness of the MDF + ball burnished samples using Deep Neural Network (DNN) approach. For the analysis, depth of press, feed and number of passes served as inputs for the DNN model. After configuring and training procedure of the model, the predicted roughness and microhardness of the MDF + ball burnished were compared with the results of experimental data. A large increase of microhardness was observed for MDF-5 + BB-1 (5 pass MDF processed Mg-2%Zn alloy + Ball burnished sample), found to be 98 Hv and surface roughness of 306 nm was achieved. According to the results, the obtained R-squared value is very close to the 99.5 percentage from the model for predicting roughness and hardness which is a promising result. Corrosion behavior of the AS-1, MDF-5 and MDF-5 + BB-1 was evaluated in Hank's balanced salt solution. Corrosion rate of the MDF-5 + BB-1 samples were found to be 0.87 mm/y which is 7 times better than that of AS-1 samples (6.10 mm/y). Grain refinement and residual stresses were higher in the MDF-5 + BB-1 sample, which helped significantly to enhance corrosion resistance. © 2021 The Society of Manufacturing EngineersItem 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 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.Item 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.