الفهرس 
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Abstract
Metal matrix composites (MMCs) are gaining increasing attention for applications in aerospace, defense and automobile industries. In this work, composite specimens of aluminum alloy (AA6063) based matrix, reinforced with different weight fractions of nikel particulates up to 50% weight are fabricated by stirring method followed by squeeze casting technique using different fabrication pressures up to 250 . The present work includes a mathematical model to predict the distribution of nikel particulates inside (AA6063) matrix alloy. The model demonstrates the relationships between the particle acceleration and fabrication pressure through different weight fractions of nikel particulates. The obtained mathematical relationships can predict the maximum height of the composite material for different weight fractions of the reinforcement and fabrication pressures. The optimum fabrication pressure required to avoid the agglomeration phenomena of the reinforcing particulates are investigated using the kinematic analysis of the grain pattern. The physical and mechanical properties of the composite specimens are investigated. For each specimen, microstructure, density, hardness and tensile strength tests have been carried out. Moreover, Specimens of metal matrix composites have been machined using a center lathe under different cutting conditions using coated carbide inserts. The machinabinability has been evaluated through the measurement of the main cutting force component, tool wear, tool life, surface roughness, and chip formation.
The obtained results indicate that at low fabrication pressure, the nikel particulate appear to be distributed in the matrix alloy in the shape of continuous patterns of linear and parallel trends. The increase of fabrication pressure changes the formation pattern of nikel particulates from a continuous to a discontinuous pattern.
The density of the composite specimens increases with the increase of the weight fabrication of Nikel particulates. The hardness of the composites increases with both increasing of the weight fabrication and the fabrication pressure. There s a significant increasing in the ultimate tensile strength and decrease of ductility by increasing the weight fraction of Nikel particulates in the matrix alloy. The electrical conductivity of the composite decreases with the increase of the weight fraction and increases with the increase of fabrication pressure up to 150 MPa.
In addition, the tool life decreases considerably with increase the weight fractions of nikel particulates for all tests The present work manifests the emperial relationships between tool life and cutting conditions for the used tool.
The mathematical model indicates that the reinforcing particulates are concentrated in the lower zone of composite ingot and gradually decrease towards the top zoneof the ingot. These trends are observed also in the experimental results, where a vertical section of the composite ingots shows a good agreement with the results obtained throughout the work.