الفهرس | Only 14 pages are availabe for public view |
Abstract Because of its interesting properties, Cu has recently received great interest in a variety of industrial fields, including electrical communications in electronics, machinery, civil engineering, automobiles, and other important industrial applications. Among these outstanding properties are its high thermal and electrical conductivity. In contrast, the main disadvantages of Cu are its poor mechanical properties, high thermal expansion coefficient (CTE) value, and low wear resistance, which limit its technological applications. As a result, this thesis aims to improve the aforementioned properties of Cu by preparing Cu-based nanocomposites enhanced with hybrid ceramics in the nanometer range. Three groups of nanocomposites were prepared, optimized with different proportions of SiC-FA, FA-Gr, and SiC-Gr, respectively, using the powder metallurgy method. The percentages of SiC and FA added varied at 0, 1, 2, 4, and 8 volume percentage, while Gr was added at 0, 0.1, 0.2, 0.4, and 0.8 volume percentages. The Cu based hybrid nanocomposites were prepared in two stages. The first is mixing and milling the nanocomposite powders in a high-energy ball mill for 20 hours at a speed of 440 rpm. The second stage is pressing the prepared powders at a pressure of 30 MPa and sintering them at 700, 800, and 850 °C for one hour in an argon atmosphere. XRD and TEM analyses were used to examine the phase changes of milled powders and particle properties (shape and size), and the microstructure of the sintered nanocomposites was tested by FESEM. The physical properties (bulk density, relative density, and apparent porosity) and mechanical properties, including microhardness, compression test, and elastic modulus (using ultrasound technology), were also measured for the sintered nanocomposites. In addition, thermal expansion |