Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
5 results
Search Results
Item Influence of Chloride Content and Exposure Time on Corrosion Behavior of AZ80 Wrought Mg Alloy(Springer Nature, 2020) Gote, G.D.; Naik, G.M.; Narendranath, S.This study aims to investigate the corrosion behavior of wrought AZ80 magnesium alloys in different chloride ion concentrations and exposure time. During the study, the effect of exposure time and chloride content on the corrosion resistance of AZ80 wrought Mg alloy has been studied with 2, 3.5, and 5 wt% NaCl aqueous solution for 12 h and 24 h exposure time. Charge transfer resistance for each sample was established using the Nyquist plot and corrosion rate obtained from polarization curve by adopting Tafel extrapolation method. Corrosion morphology was examined using scanning electron microscopy and XRD. The study revealed that corrosion product layer formed at initial stage was observed unstable after short exposure time which results in decrease in corrosion resistance at initial stage. An increase of chloride content in aqueous environment reduces the corrosion resistance of AZ80 wrought Mg alloy. © 2020, Springer Nature Singapore Pte Ltd.Item Microstructural and Hardness evolution of AZ80 alloy after ECAP and post-ECAP processes(Elsevier Ltd, 2018) Naik, G.M.; Gote, G.D.; Narendranath, S.This research paper investigates the microstructure evolution and hardness variation of wrought AZ80 magnesium alloy after each ECAP passes. The strengthening effect of AZ80 alloy was examined after post-ECAP aging treatment. Alloys were severely deformed through equal channel angular press at 533K using route Bc with a die channel angle (φ) 1100 and corner angle (ψ) 300. Subsequently, the microstructural characterization was studied using optical microscope (OM) and scanning electron microscope (SEM). Further, post-ECAP aging treatment at 523K for 6h and 12h was performed and microhardness of the specimens was measured. It was found that the grain refinement through thermo-mechanical processing of ECAP and Post-ECAP treatment significantly improves the microhardness of the Mg alloy, which directly influences the properties of wrought AZ80 magnesium alloy. © 2018 Elsevier Ltd. All rights reserved.Item Microstructure and Corrosion behavior of wrought AZ80 Mg alloys after the combined processes of ECAP and Hot Rolling(IOP Publishing Ltd, 2019) Naik, G.M.; Gote, G.D.; Narendranath, S.; Satheesh Kumar, S.S.In the current work, wrought AZ80 Mg alloys were subjected to equal channel angular pressing (ECAP) followed by hot rolling (HR). Then, combined effects of ECAP and HR on microstructure and electrochemical corrosion behavior were investigated in 3.5wt.% NaCl solution. The microstructure and corrosion morphology study was made through optical and scanning electron microscope respectively. The results show that the use of hot rolling after ECAP significantly decreases the grain size compared to as-received and ECAP-4 pass processed Mg alloys. In addition, electrochemical impedance spectroscopy and potentiodynamic polarization results have shown that the hot rolling of AZ80 Mg alloy after ECAP exhibited lower corrosion current and higher corrosion resistance is due to fine grain microstructure and continuous and uniform distribution of secondary phases. This was evidently observed during this study. © Published under licence by IOP Publishing Ltd.Item Effect of grain refinement on the performance of AZ80 Mg alloys during wear and corrosion(Techno-Press info@techno-press.com, 2018) Naik, G.M.; Gote, G.D.; Narendranath, S.; Satheesh Kumar, S.S.Magnesium and its alloys are attracted towards all engineering applications like automotive, marine, aerospace etc. due to its inherent high strength to weight ratio. But, extensive use of Mg alloys is limited to the current scenario because of low wear and corrosion resistance behavior. However, equal channel angular press is one of the severe plastic deformation technique which has been effective method to improve the wear and corrosion resistance by achieving fine grain structure. In this study, the effect of grain refinement on wear and corrosion resistance of AZ80 Mg alloys were investigated. The wear behavior of the coarse and fine-grained Mg alloys was examined through L9 orthogonal array experiments in order to comprehend the wear behavior under varies control parameters. It was shown that ECAPed alloy increased the wear and corrosion resistance of the Mg alloy through the formation of fine grain and uniform distribution of secondary beta - phase. Also, the performance of AZ80 Mg alloy for these changes was discussed through SEM morphology. © 2018 Techno-Press, Ltd.Item The impact of homogenization treatment on microstructure microhardness and corrosion behavior of wrought AZ80 magnesium alloys in 3.5 wt% NaCl solution(Institute of Physics Publishing helen.craven@iop.org, 2018) Naik, G.M.; Gote, G.D.; Narendranath, S.; Satheesh Kumar, S.S.This paper investigates the effect of homogenization treatment on microstructure, micro-hardness and corrosion behavior of AZ80 wrought Magnesium alloy. Homogenization at 523 K, 623 K, and 723 K were accomplished. Meanwhile samples were cooled in the furnace after 6 h and 12 h of diffusion annealing treatment. In this study, samples were characterized by using optical microscopy (OM) and scanning electron microscopy (SEM). Micro-hardness of the homogenized specimens were measured and electrochemical corrosion behavior of homogenized AZ80 alloy has been investigated. Attempt has been made to enhance both the hardness and corrosion resistance of the AZ80 Mg alloy by changing its microstructure during homogenization treatment. This investigation revealed that the hardness of Mg alloy is improved at 523 K-12 h holding time. It was also found that corrosion rates are minimum at higher homogenization temperature and lower holding time because of uniform distribution of secondary ?-phases in Mg matrix, evidently shown in the microstructure of the heat treated Mg alloy. As a result, the homogenization treatment at 723 K for 6 h is desirable to enhance the corrosion resistance. © 2018 IOP Publishing Ltd.