4983
Mahmoud Nasr El-Din Mohammed
Preparation and characterization of metal matrix composites reinforced with Al2O3 particles using Mechanical alloying
mechanically alloyed / metal matrix composites. / (Al/ Al2O3)
This research focuses on studying the influence of milling time on the properties of metal matrix powders composites as well as their sintered bodies. Powders of Al matrix reinforced with different percentages of Al2O3 (i.e. 0, 5, 10, 15, 20 wt. %) were subjected to high energy ball milling (550 rpm) up to 20 h. Phase evolution and morphological changes of the milled samples were examined using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD was also used to determine lattice parameter, crystallite size and lattice strain. An attempt was made to consolidate that the mechanically alloyed nanopowders have produce bulk Al/ Al2O3 compositesThe powders were pressed at room temperature at 10 MPa by a hydraulic machine. The compacted specimens were sintered in a controlled argon atmosphere furnace at different temperatures with heating rate 8ºC/min. Al/Al2O3 were sintered at 300,370, and 470 ºC. As the temperature was increased two adjacent particles begin to form a bond by diffusion (solid-state bonding) to near to approach the theoretical density. The bulk density and apparent porosity of the sintered specimens were measured by Archimedes methodOptical imaging was achieved for all sintered samples, in order to investigate the microstructure. Scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDX) were used to investigate the microstructure and micro analysis of the obtained phases, respectively
2015
Ph.d
Al-Azhar
Science