Conference Papers
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Item Effect of aging and protective coating on the corrosion behavior of 6061 Al / SiCp composite in chloride solutions(Trans Tech Publications Ltd ttp@transtec.ch, 2011) Rajasekaran, S.; Udayashankar, N.K.; Nayak, J.Metal matrix composites considered especially for marine application are typically aluminum-based. Utilization of the composites in marine environments requires adequate corrosion resistance. In this work, the effect of aging and aluminum as resistive coating on the corrosion behavior of 6061 Al / SiC p composite in 1N and 3.5N NaCl solution in the temperature range of 30°C-50°C is studied by means of electrochemical techniques, scanning electron microscope (SEM) and weight loss measurements. Aging results in precipitation of intermetallics in the matrix, this in turn leads to galvanic and pitting corrosion. Pitting initiation and propagation as the main corrosion mechanism was driven by the aging kinetics which is ruled by the reduction in the retained vacancy concentration and at the same time by dislocation density due to the presence of SiCp. Sputtered aluminum coating on the composite effectively resists the pitting initiation and propagation and hence corrosion process. Also the intermetallic precipitates are unexposed to the Chloride solution by the presence of aluminum coating. Hence aluminum coating acts as corrosion resistive coating for the 6061 Al / SiCp aged composites. © (2011) Trans Tech Publications.Item Equal channel angular pressing of aluminum-alumina insitu metal matrix composite(Trans Tech Publications Ltd ttp@transtec.ch, 2012) Athreya, C.N.; Mahesh, V.P.; Brahmakumar, M.; Rajan, T.P.D.; Prabhu, K.N.; Pai, B.C.; Gupta, R.K.; Ramkumar, P.The present investigation is on synthesis of in situ Al-alumina composite and to evaluate the effect of equal channel angular pressing on the refinement of the grain structure and enhancement in the hardness and the strength. The billets pressed in as cast condition has shown cracks during first pass. The billets pressed immediately after solution treatment for one pass and followed by ageing treatment immediately after pressing exhibited very high hardness of 125BHN against 95 BHN to that of the T6 condition of 6061 aluminium alloy. The microstructural refinement from 35 μm to 11 μm is obtained in annealed and ECAP 2 pass condition. © (2012) Trans Tech Publications.Item Effect of plastic strain and processing routes on the hardness of as-cast aluminum(American Institute of Physics Inc. subs@aip.org, 2020) Valder, J.; Rijesh, R.; Kumar, P.; Saminathan, S.; Raju, K.; Surendranathan, A.O.In the present study, Equal Channel Angular Pressing (ECAP) of commercially pure aluminum (Al) in the cast form was carried out at room temperature for assessing its hardness by different routes and passes. The different routes employed in the present investigation are A, BA, BC and C. The Al specimens were pressed by a die of 150° channel angle without back pressure with Molybdenum disulfide (MoS2) as the lubricant. ECAP has significantly improved the hardness of Al in the subsequent passes. It has been observed that the hardness has been increased after first pass at room temperature from 47 VHN in the annealed condition to 54 VHN and after the second pass the hardness value has been increased to 56, 57, 62 and 56 VHN for routes A, BA, BC and C respectively. The increase in the hardness may be attributed to the severe fragmentation of microstructure of cast Al and the change in the orientation of the specimen from one pass to the next pass. After one pass, the dendritic microstructure of cast Al has been distorted by the shear stress developed during deformation. The processing by different routeswith number of passes has further refined the microstructure leading to a better hardness in the cast Al. © 2020 Author(s).