Elena Brandaleze; Martina Avalos; Mykaylo Romanyuk
Abstract
Steel wires under severe cold drawing deformation, develop high strength (5-6 GPa) and ductility. For these reasons it is relevant to increase the knowledge on the structural evolution and deformation mechanisms involved during wire drawing process, due to their critical applications such as bridges, ...
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Steel wires under severe cold drawing deformation, develop high strength (5-6 GPa) and ductility. For these reasons it is relevant to increase the knowledge on the structural evolution and deformation mechanisms involved during wire drawing process, due to their critical applications such as bridges, cranes and tire cord. This paper presents a comparative study of steel wires (0.84%C) at different deformation stages. The product presents a normal behaviour under torsion test, the mentioned test is normally used to corroborate the wire aptitude. The main objective of the study is to increase the knowledge on the structural evolution after cold drawn considering the deformation mechanisms, cementite dissolution, and epsilon carbide precipitation. The microstructural study was carried out applying light and scanning electron microscopy (SEM-EBSD). The structural information was correlated with results of differential thermal analysis (DTA) and FactSage simulation. The structural study verified the presence of curling phenomenon in the wires. The interlaminar spacing (l) and the thickness of cementite lamellae in wires cold drawn from 8 mm up to 2 mm of diameter was determined. Finally, the dynamic strain aging, which is promoted by cementite destabilization and the precipitation of epsilon carbide was studied. Copyright © 2018 VBRI Press.
Subhash Nimanpure; S. A. R. Hashmi; Rajnish Kumar; Archana Nigrawal; H.N. Bhargaw; Ajay Naik
Abstract
Environment friendly electrical insulation material was developed using bio based rectangular cross sectioned sisal fibrils as reinforcement. High content cellulose base fibrils fibrillated by mechanical disintegration method into macro and micro fibrils from coarse sisal fibre. This fibrils were randomly ...
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Environment friendly electrical insulation material was developed using bio based rectangular cross sectioned sisal fibrils as reinforcement. High content cellulose base fibrils fibrillated by mechanical disintegration method into macro and micro fibrils from coarse sisal fibre. This fibrils were randomly distributed in polymer matrix. These composites were characterized in term of electrical, mechanical and thermal properties to investigate the stability for high strength electrical insulation materials. Excellent mechanical properties were observed. Tensile, flexural and impact strength of composites at 40 wt. % fibril loading improved by 151.34, 197.43 and 360.07 % as compared to unsaturated polyester resin. A few micro-mechanical models were compared with the experimental values. Nielson-Chen Model predicted the experimental data most accurately. The electrical properties of surface modified sisal fibril composites improved significantly in higher frequency. DSC analysis showed that the decomposition temperature of composite was higher, around 22°C than that of the polyester resin. Thermal degradation reduced and was observed in the range of 83-87% of fibril composites as compared to 97% of resin. Fibril composites are highly sensitive to electrical frequency and exhibit excellent electrical insulation property at 20 kHz. Alkali treated fibril based composites resulted an environment friendly thermally stable, high strength insulation material. Copyright © 2018 VBRI Press.
Hitesh R. Ashani; Sachin P. Parikh; Jaysukh H. Markna
Abstract
Nanotechnology is considered as one of the active research area of 21st century due to its increasing economic importance and ability to study the material at nano scale to improve its behavior in construction industry. Concrete the second highest consume commodity on the planet after water is highly ...
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Nanotechnology is considered as one of the active research area of 21st century due to its increasing economic importance and ability to study the material at nano scale to improve its behavior in construction industry. Concrete the second highest consume commodity on the planet after water is highly heterogeneous material with thumping performance challenges on it. Demand of concrete is increasing due to increasing demand for infrastructure development, rapid urbanization, rapid industrial development, population growth, economic development of the nation etc. A little diminution in the number of problems related with concrete would add up to noteworthy recital enhancement and economic benefits to society and nation. In the present communication, the cement one of the main ingredient of concrete was replaced with a range of5%, 10%, 15% and 20 % of the weight of cement by nano carbon material to study the effect on the mechanical properties like – compressive strength, surface hardness, water absorption, consistency, morphology on nano carbon concrete specimen. A rapport was made between standard and nano carbon black concrete specimen to arrive at a legitimate conclusion that improvement in the mechanical properties like strength, hardness, compactness etc. and C-S-H gel structure is obtained. Copyright © 2017 VBRI Press.
Brijesh Prasad; Bhingole P P
Abstract
Magnesium and its alloys have got great attention in recent times due to its potential to replace heaver alloys with equal strengths and lighter in weight, hence become potential materiel automobile, sports, aeronautical and biomaterials applications This study concentrates and summarizes ...
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Magnesium and its alloys have got great attention in recent times due to its potential to replace heaver alloys with equal strengths and lighter in weight, hence become potential materiel automobile, sports, aeronautical and biomaterials applications This study concentrates and summarizes the fundamental properties of magnesium and its alloys such as high strength, ductility non-corrosive behavior etc. Along with its developments in its physical metallurgy, forming process and strengthening mechanisms to enhance the mechanical strength followed by behavior of magnesium alloys under different working conditions and applications. A brief overview of the recent and systematic outline is reported for improvement of mechanical by strengthening mechanism along with its applications. This work would be very much helpful for the researchers to find the best strengthening method on looking on its various aspects of design, environment friendly behavior and optimum utilization of resources with saving the natural resources. Copyright © 2017 VBRI Press.
Rajnish Kumar; S. A. R. Hashmi; Subhash Nimanpure; Ajay Naik
Abstract
Randomly distributed kenaf fibre with varying length (5-50mm) and weight fractions (25-40%) were used to reinforce epoxy resin to prepare environment friendly composites. Effect of fibre length with constant fibre loading on dynamic mechanical properties was studied and its effect on storage modulus, ...
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Randomly distributed kenaf fibre with varying length (5-50mm) and weight fractions (25-40%) were used to reinforce epoxy resin to prepare environment friendly composites. Effect of fibre length with constant fibre loading on dynamic mechanical properties was studied and its effect on storage modulus, loss modulus and damping factor were investigated. Kenaf fibres were also subjected to alkali treatment to improve interaction with the epoxy resin. The mechanical properties of composites improved with the length and loading of fibres. Tensile strength, flexural strength and impact strength of composites at 40 wt% of fibre reinforcement improved by 46, 51 and 97% as compared to the composites containing 25 wt% of kenaf fibre. It was also observed that fibre folds developed during mixing became significant factor which limited the improvement in mechanical strength of kenaf epoxy composites. A few important predictive models namely rule of mixture, Haplin-Tsai, Nielson Chen and Manera models were compared with the experimental values obtained in this present study. Manera model predicted the experimental data most accurately. Alkali treatment improved the interface and its outcome reflected in the improved modulus that increased 21.76% in samples having 10mm length of kenaf fibre. Copyright © 2017 VBRI Press.
