Browsing by Author "El-Kady, Omayma"

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    Effect of diamond additions on the microstructure, physical and mechanical properties of WC- TiC- Co/Ni Nano-composite
    (ELSEVIER SCI LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND, 2018-02) Yehia, H. M.; El-Kady, Omayma; Abu-Oqail, Ahmed
    WC- TiC- Co- Ni/diamond composites have been prepared by powder metallurgy technique. 2.5%, 5%, 7.5% and 10 wt% diamond were added. WC- TiC- Co/diamond was coated with 12 wt% nickel by the electro-less deposition process. All the samples were compressed at 700 MPa then sintered at 1450 for 1 h. XRD, EDAX, and microstructure were investigated. Density, electrical resistivity, thermal conductivity, magnetic properties, the coefficient of thermal expansion, fracture toughness and hardness were studied. The results of XRD and EDAX analysis show that new phases were formed. It also revealed that the diamond content has a positive effect on the thermal properties of composites. Presence of Ni content improves the Fracture toughness of the composites but decreases the hardness.
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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.