Browsing by Author "Yehia, Hossam M."

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Effect of graphene nano-sheets content and sintering time on the microstructure, coefficient of thermal expansion, and mechanical properties of (Cu/WC-TiC-Co) nano-composites
(ELSEVIER SCIENCE SA, PO BOX 564, 1001 LAUSANNE, SWITZERLAND, 10/05/2018) Yehia, Hossam M.; Nouh, F.; El-Kady, Omayma
The effect of nano-graphene sheets on the thermal expansion and mechanical properties of Cu/WC-TiC-Co composite was studied. Five samples with 0, 0.25, 0.5, 0.75, and 1 wt. % graphene were prepared. 10 wt. % WC-TiC-Co was coated with 90 wt.% copper by electro-less coating process then mixed with the different weight percent of graphene anno-sheets. All composites were compacted at 900 MPa then sintered in an argon atmosphere at 950 degrees C at three different times 90, 120, 140 min. Volume shrinkage, density, microstructure, thermal expansion, hardness, and compression strength were measured. Sintered samples at 950 degrees C for 140 min expedited the highest volume shrinkage and density. Thermal expansion, hardness, and compression strength were improved as a result of reinforcing composites with graphene up to 1 wt. %. (C) 2018 Elsevier B.V. All rights reserved.
Electrochemical Surface Modification of Aluminum Sheets Prepared by Powder Metallurgy and Casting Techniques for Printed Circuit Applications
(SPRINGER INDIA, 2019) Yehia, Hossam M.; Elkady, Omayma A.; Reda, Y.; Ashraf, K.E
Two series of Al sheets are coated with different thicknesses of copper-deposited film from 10 to 40 mu m by the electroplating technique. The first group is the fresh cast Al sheets, and the other is the recycled water-atomized Al powder prepared by the technique of powder metallurgy. Microstructure and phase structure were examined by XRD, optical microscopy and FESEM. Electrical conductivity, thermal conductivity and coefficient of thermal expansion (CTE) were investigated. The XRD showed that only Al and Cu peaks appeared for the cast Al sheet samples, but for the recycled ones other peaks corresponding to Al2O3 were also detected. The microstructure indicated that the coated Cu layer had a dendritic structure in a continuous pattern, but for the recycled samples the dendritic structure was not clear but continuous. Both the thermal and electrical conductivities were gradually increased along with the increase in the Cu thickness, while the CTE was decreased