Faculty Publications
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Item Machining characteristics of nanocomposites(2011) Umashankar, K.S.; Gangadharan, K.V.; Desai, V.; Shivamurty, B.Nanocomposites were prepared with Al/Al-Si alloys (LM 6 and LM 25) as matrix and multi wall carbon nanotube (MWNT) of 0.25, 0.5, 0.75, 1.0 and 1.5 wt. % as reinforcement through powder metallurgy (PM) followed by sintering and hot extrusion techniques. Fabricated nanocomposites were machined on a Panther 1530/1650 lathe by using tungsten carbide tool. Recurrence quantification analysis (RQA) was used to study the machining characteristics by using cutting force signal stability. Highest value ofdeterminism (DET-one of the RQA parameter) was observed for 0.5 wt.% MWNT reinforced Al and Al-Si nanocomposites. This attributes better machining characteristic due uniformity of the signals. Also it is observed better mechanical properties at 0.5 wt.% reinforced nanocomposite and further reinforcement deteriorate the machinability and mechanical properties. © 2011 VBRI press.Item Machining characteristics of multiwall-CNT reinforced Al/Al-Si composites using recurrence quantification analysis(2011) Gangadharan, K.V.; Umashankar, K.S.; Ravish; Desai, V.Aluminium (Al)/Aluminium alloy composites are emerging as very promising materials, especially in the fields of aerospace and automotive for their various attractive and technically demanding properties. Discontinuously reinforced aluminium metal matrix composites with reinforcements as nanoparticles of ceramics in general and carbon nanotubes in particular have emerged as the forerunner for a variety of general and special engineering and structural applications. In many of the fields where these materials find applications, machining is invariably required for getting correct geometries, dimensions and surface finish of the components. Hence, establishing the machining characteristics of these materials in terms of the deterministic nature of dynamic signals such as cutting force signals and vibration signals is very important and sought after. Machining process has been understood to be nonlinear and chaotic in nature. In this paper a relatively new technique called Recurrence Plots (RP) and Recurrence Quantification Analysis (RQA), a tool to analyse nonlinear and chaotic systems, is used to study the machining characteristics of cast and powder metallurgy Al and Al-Si alloys (LM6 and LM25), CNT reinforced Al/Al-Si composites produced by powder metallurgy route. Cutting force signals were sensed, acquired and analysed using RQA technique. Determinism (DET), which is one of the variables of RQA, indicates the determinism present in a signal. The values of DET were used to compare the machining characteristics. For all the three materials the deterministic nature of the cutting force signal was highest when reinforced with 0.5 weight percentage CNT, followed by respective base alloys produced by powder metallurgy method and casting route. © 2011 Jordan Journal of Mechanical and Industrial Engineering.Item The influence of the addition of 4.5 wt.% of copper on wear properties of Al-12Si eutectic alloy(Hashemite University huniv@hu.edu.jo, 2015) Channappagoudar, S.; Kiran Aithal, K.; Sannayallappa, N.; Desai, V.; Mukunda, P.G.The influence of 4.5 wt.% copper addition on wear behavior of as-cast Al-12Si alloy prepared by gravity casting is investigated in dry sliding against a steel counterface using a pin-on-disk apparatus. The microstructures of test alloys and worn surfaces were examined by scanning electron microscopy and energy dispersing X-ray spectroscopy. The addition of copper to the binary Al-12Si alloy led to the precipitation of CuAl2 phase. Copper addition resulted in a refinement of ?-Al and a minor modification of eutectic Si. The Al-12Si-4.5Cu alloy showed a higher wear resistance as compared to Al-12Si binary eutectic alloy. © 2015 Jordan Journal of Mechanical and Industrial Engineering. All rights reserved.Item Influence of combined grain refinement and modification on the microstructure, tensile strength and wear properties of Al-15Si, Al-15Si-4.5Cu alloys(Carl Hanser Verlag Kolbergerstrasse 22 Munchen D-81679, 2015) Channappagoudar, S.; Sannayallappa, N.; Desai, V.; Venkateswarlu, V.Microstructure, tensile strength and dry sliding wear studies of Al-15Si, Al-15Si-4.5Cu alloys with and without grain refinement and modifications are presented. Experimental alloys such as Al-15Si and Al-15Si-4.5Cu were conventionally melted and gravity die cast. For grain refinement, 1 wt.% of Al-1Ti-3B and for modification, 0.17 wt.% of aluminum phosphide (AlP) and 0.4 wt.% of Al-10Sr were added to the alloy melt. The results reveal refined microstructure due to grain refinement, modification, improved hardness, higher tensile strength and better sliding wear. Moreover, Al-15Si-4.5Cu alloy (untreated and treated) showed improved mechanical properties as compared to conventional hypereutectic Al-Si alloy. © Carl Hanser Verlag GmbH & Co. KG.Item Influence of combined grain refinement and modification on the Microstructure, tensile strength and wear properties of Al-15Si, Al-15Si-4.5Cu alloys(Carl Hanser Verlag Kolbergerstrasse 22 Munchen D-81679, 2015) Channappagoudar, S.; Sannayallappa, N.; Desai, V.; Venkateswarlu, V.Microstructure, tensile strength and dry sliding wear studies of Al-15Si, Al-15Si-4.5Cu alloys with and without grain refinement and modifications are presented. Experimental alloys such as Al-15Si and Al-15Si-4.5Cu were conventionally melted and gravity die cast. For grain refinement, 1 wt.% of Al-1Ti-3B and for modification, 0.17 wt.% of aluminum phosphide (AlP) and 0.4 wt.% of Al-10Sr were added to the alloy melt. The results reveal refined microstructure due to grain refinement, modification, improved hardness, higher tensile strength and better sliding wear. Moreover, Al-15Si-4.5Cu alloy (untreated and treated) showed improved mechanical properties as compared to conventional hypereutectic Al-Si alloy. © Carl Hanser Verlag GmbH & Co. KG ISSN 1862-5282.