Conference Papers

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    A pressured steam JET approach to tool wear minimization in cutting of metal matrix composites
    (Trans Tech Publications Ltd, 2007) Anjaiah, D.; Shetty, R.; Pai B, R.; Vijaya, M.V.; Rao, S.S.
    Metal matrix composites (MMCs) have been found to possess tremendous prospective engineering applications that require materials offering a combination of lightweight with considerably enhanced mechanical and physical properties. However, the applications of MMCs are limited by their poor machinability which is a result of their highly abrasive nature that causes excessive wear to the cutting tools. In this study, an investigation into the mechanism of the tool wear in cutting of MMCs is carried out. It is found that during cutting of an MMC, the tool cutting edge will impact on the reinforcement particles. The impacted particles will then either be dislodged from the matrix, doing no harm to the tool, or be embedded into the matrix, ploughing on the tool flank and causing excessive tool flank wear. According to this tool wear mechanism, a pressured steam jet approach is developed for the minimization of the tool wear by preventing the impacted reinforcement particles from being embedded in the workpiece matrix. Experimental tests for cutting of SiC-aluminum MMC using cubic boron nitride (KB-90) and polycrystalline diamond (KP-300) tool inserts with the aid of the pressured steam jet are conducted. The results show that from full factorial design of experiments the effect of the pressured steam jet plays a significant role on the tool wear followed by tool inserts and depth of cut. The working mechanism of the pressured steam jet method and the experimental testing results are discussed in detail.
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    The effect of aging and the protective coating on the oxidation behavior of 6061Al/SiC composite at high temperatures
    (Trans Tech Publications Ltd ttp@transtec.ch, 2011) Rajasekaran, S.; Udayashankar, N.K.; Nayak, J.
    This paper analyses the effect of ageing on the oxidation behavior of 6061Al/SiC composite material at temperatures ranging from 500 to 800 K. Also aluminum coating is employed as protective coating in order to improve the oxidation resistance of the composite. SEM, EDAX, XRD and stepped oxidation measurement techniques are used to study the oxidation behavior and to characterize the composite specimens. Oxidation of the composite material without protective coatings is seen to be very rapid during the initial stages of exposure to the high temperatures but subsequently slowed down due to the formation of a protective surface layer of oxide. Among the artificially aged composites, peak aged specimens are more prone to oxidation. The oxidation was especially severe above 600 K. The interface between the matrix and reinforcement particles and the grain boundary regions of the matrix enhance this oxidation process since they provided sites for oxidation initiation. Aluminum coating on the composite obtained by DC magnetron sputtering technique, reduce the oxidation rate effectively since the interface regions between the matrix and reinforcement, grain boundary regions of the matrix are unexposed to the atmosphere. Aluminum coating provides better oxidation resistance for the artificially aged composites. © (2011) Trans Tech Publications.
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    The effect of protective coatings on the oxidation behavior of 6061Al/SiC composite at high temperatures
    (2012) Udayashankar, N.K.; Rajasekaran, S.; Nayak, J.
    This paper analyses the effect of protective coatings on the oxidation behavior of 6061Al/SiC composite material at temperatures ranging from 500 to 800 K. Aluminum and AlCrN coatings are employed as protective coatings in order to improve the oxidation resistance of the composite. SEM, EDAX, XRD and oxidation measurement techniques are used to study the oxidation behavior and to characterize the composite specimens. Oxidation of the composite material without protective coatings is seen to be very rapid during the initial stages of exposure to the high temperatures but subsequently slowed down due to the formation of a protective surface layer of oxide. The oxidation was especially severe above 600 K. The interface between the matrix and reinforcement particles and the grain boundary regions of intermetallic precipitates in the matrix enhance this oxidation process since they provided sites for oxidation initiation. Aluminum coating on the composite obtained by DC magnetron sputtering technique and AlCrN coating obtained by low voltage electron beam evaporation technique reduce the oxidation rate effectively since the interface regions between the matrix and reinforcement, grain boundary regions of the matrix are unexposed to the atmosphere. Aluminum coating provides better oxidation resistance for 6061 Al/SiC composites.
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    Application of response surface methodology and enhanced non- Dominated sorting genetic algorithm for optimisation of grinding process
    (Elsevier Ltd, 2013) Dayananda Pai, D.; Rao, S.; D'Souza, R.
    Optimisation of grinding process during grinding of A16061-SiC composites is investigated in this study. Stir cast A16061-SiC composites with varying volume percentage of SiC reinforcement were ground on a conventional grinding machine with diamond grit grinding wheel. Three grinding variables were studied for simultaneous optimization of material removal rate and surface roughness. Initially, the response surface models for grinding process parameters were developed using response surface methodology. Further, the developed models were optimized using enhanced elitist non-dominated sorting genetic algorithm (enhanced NSGA-II), a time saving algorithm in comparison to conventional NSGA-II. The suitable grinding conditions for multi-objective optimization of the grinding process were obtained from enhanced NSGA-II. Finally the confirmation tests were performed to validate the results obtained from response surface methodology and enhanced NSGA-II. It is observed that, experimental results and the results obtained from enhanced NSGA-II are in close conformance. Hence it is concluded that the developed algorithm can effectively be used for optimization of grinding process. © 2013 The Authors. Published by Elsevier Ltd.