Faculty Publications
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Item Microstructure, microhardness, and tensile properties of hot-rolled Al6061/TiB2/CeO2 hybrid composites(South African Institute of Mining and Metallurgy, 2021) Iyengar, S.; Sethuram, D.; Shobha, R.; Koppad, P.G.TiB2 and CeO2 particle-reinforced Al6061 hybrid composites were manufactured using stir casting and hot rolling techniques. The base alloy and composites were hot-rolled at 500ºC and a 50% reduction was achieved through 12 passes. The effect of varying TiB2 and CeO2 particle additions on the microstructure and mechanical properties of the Al6061 matrix was studied. Scanning electron microscopy showed uniform dispersion of both the reinforcements, with good interfacial bonding. Microhardness and tensile properties like yield and tensile strength were found to be higher for hybrid composite with 2.5% TiB2 and 2.5% CeO2 compared to Al6061 alloy and other hybrid composites. The increased tensile strength is attributed to good dispersion and interfacial bonding between the particles and Al6061 matrix. Fracture analysis using a scanning electron microscope revealed ductile fracture for the Al6061 alloy and mixed characteristics of ductile-brittle fracture for hybrid composites. © 2021 South African Institute of Mining and Metallurgy. All rights reserved.Item Hardness and electrical conductivity of uncoated and silver coated carbon nanotubes reinforced copper nanocomposites(Springer, 2022) Koti, V.; Mahesh, n.; Murthy, K.V.S.; Koppad, P.G.; Sethuram, D.In the present study, carbon nanotube reinforced copper nanocomposites were fabricated using the powder metallurgy technique which includes ball milling and hot pressing. The carbon nanotube weight percentage in the nanocomposite was varied from 0.25 to 1.50% in the steps of 0.25%. Further, to improve the interfacial bonding between the carbon nanotubes and copper matrix, the carbon nanotubes were coated with silver using the electroless deposition method. The sintered and hot pressed copper nanocomposites with uncoated and silver-coated carbon nanotubes were subjected to optical and scanning electron microscope studies to understand the dispersion of nanotubes. The density, microhardness and electrical conductivity of developed nanocomposites were studied. The dispersion of nanotubes was found to be uniform throughout the copper matrix resulting in the improvement in microhardness. Especially when compared with sintered samples, the hot-pressed nanocomposites with silver-coated carbon nanotubes showed significant improvement in microhardness however beyond 0.75% content the microhardness for samples was found to drop. The electrical conductivity of nanocomposites was found to decrease with the increase in the MWCNT content which was attributed to the clustering of MWCNTs due to strong van der Waal forces and the increase in the number of interfaces between MWCNTs and copper matrix. © 2022, Indian Academy of Sciences.