Faculty Publications
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Item Mechanical and tribological behaviour of epoxy reinforced with nano-Al2O3 particles(Trans Tech Publications Ltd ttp@transtec.ch, 2014) Kurahatti, R.V.; Surendranathan, A.O.; Ramesh Kumar, A.V.; Auradi, V.; Wadageri, C.S.; Kori, S.A.In the present work systematic study has been conducted to investigate the matrix properties by introducing nanosize Al2O3 (particle size 100 nm, 0.5-10 wt %) fillers into an epoxy resin. High shear mixing process was employed to disperse the particles into the resin. The experimental results indicated that frictional coefficient and wear rate of epoxy can be reduced at rather low concentration of nano-Al2O3. The lowest specific wear rate 0.7 × 10-4 mm3/Nm is observed for the composites with 1 wt.% which is decreased by 65% as compared to unfilled epoxy. The reinforcement of Al2O3 particles leads to improved mechanical properties of the epoxy composites. The results have been supplemented with scanning electron micrographs to help understand the possible wear mechanisms. © (2014) Trans Tech Publications, Switzerland.Item Phase transformation, structural evolution, and mechanical property of nanostructured feal as a result of mechanical alloying(Springer New York LLC barbara.b.bertram@gsk.com, 2009) Rajath Hegde, M.M.R.; Surendranathan, A.O.The objective of the work is to synthesize nanostructured FeAl alloy powder by mechanical alloying (MEA). The work concentrates on the synthesis, characterization, and structural and mechanical properties of the alloy. Nanostructured FeAl intermetallics are prepared directly by MEA in a high-energy ball mill. Milling is performed under toluene solution to avoid contamination from the milling media and atmosphere. Mixtures of elemental Fe and Al are progressively transformed into a partially disordered solid solution with an average composition of Fe-50 at.% Al. Phase transformation, structural changes, morphology, particle size measurement, and chemical composition during MEA are investigated by X ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS). Vickers microhardness (VMH) indentation tests are performed on the powders. The XRD and SEM studies reveal the alloying of elemental powders as well as transition to nanostructured alloy; crystallite size of 18 nm is obtained after 28 h of milling. Expansion/contraction in lattice parameter accompanied by reduction in crystallite size occurs during transition to nanostructured alloy. Longer milling introduces ordering in the alloyed powders as proved by the presence of superlattice reflection. Elemental and alloyed phases coexist while hardness increases during MEA. copy2009 Springer Science+Business Media, Inc.Item Phase transformation, structural evolution and mechanical property of nanostructured FeAl as a result of mechanical alloying(2009) Rajath Hegde, M.M.R.; Surendranathan, A.O.Objective of the work was to synthesize nanostructured FeAl alloy powder by mechanical alloying (MEA). The work concentrated on synthesis, characterization, structural and mechanical properties of the alloy. Nanostructured FeAl intermetallics were prepared directly by MEA in a high energy rate ball mill. Milling was performed under toluene solution to avoid contamination from the milling media and atmosphere. Mixtures of elemental Fe and Al were progressively transformed into a partially disordered solid solution with an average composition of Fe-50 at % Al. Phase transformation, structural changes, morphology, particle size measurement and chemical composition during MEA were investigated by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDS) respectively. Vickers micro hardness (VMH) indentation tests were performed on the powders. XRD and SEM studies revealed the alloying of elemental powders as well as transition to nanostructured alloy, crystallite size of 18 nm was obtained after 28 hours of milling. Expansion/contraction in lattice parameter accompanied by reduction in crystallite size occurs during transition to nanostructured alloy. Longer milling duration introduces ordering in the alloyed powders as proved by the presence of superlattice reflection. Elemental and alloyed phase coexist while hardness increased during MEA. © 2009 Allerton Press, Inc.Item Forming of tubular commercial purity aluminum by ECAP(2012) Valder, J.; Rijesh, M.; Surendranathan, A.O.The equal channel angular pressing (ECAP) process is a promising technique for imparting a large plastic deformation to materials without a resultant decrease in cross-sectional area. In the present study, the suitability of this technique for the processing of tubular specimens has been investigated. Commercially pure aluminum was selected for the study. Tubular specimens were extruded to three passes using four processing routes through an ECAP die with an angle of 150 between the two intersecting channels. Sand was used as a mandrel during the pressing. Analysis of force-stroke diagram was carried out. The mechanical properties were also investigated. Improvement in mechanical properties was observed in all the routes. These investigations demonstrate that ECAP is a promising technique for improving properties of tubular materials while ensuring retention of shape (with the possibility of imparting further deformation to the specimen using the same die) and with low pressing pressures. © Taylor and Francis Group, LLC.