الفهرس 
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Abstract
the composites used in this work were by the vortex method. The matrices were either aluminum alloys of AA6101 or AA 7075. Particles of alumina (A12o3) or silicon carbide (SiC) were used as reinforcement.
The volume fraction (Vf) of these particles was 10%, and the average particle size was 20, 10 um for A12o3 and SiC respectively.
After casting , the composites were heat treates with standard heat treatment processes and, the hot rolled on a rolling machine with load capacity of 50 tons on 4 paths to reduce the thickness of casting coposites from 35 mm to nearly 11 mm.
Measurment of porosity showed that the deformation process helped in decreasing the porosit percentage and broke the agglomerates of particles, and as a result the ultimat, and yield strength increased when compared with the undeformed cases.
Peak hardness for AA 7075 and their composites was higher than these of AA6101 and their composites.
Also the time required to attain peak hardness in rolled conditions for reinforced or unreinforced alloys was
geneeally less than the time required for the as cast conditions.
The yield and ultimate tensile strength of rolled composites were higher than those of the as cast materials except for the composite of AA 6101/A12O3 for which the achived strength was lower than that of the matrix
material.
Deformation generally improved strength of each condition with the exception for AA6101 for which deformation resulted in a slight decrease in strength.
Deformation improved ductility for all conditions tested except for unreinforced AA 7075 for which a slight decrease in ductility was observed after defrmation.
Athough deformation of composite materials resulted in an improvement in ductility, the elongation percent achieved was always lower than that of the as cast material.
Using a design of experiment (DOE) method, which strongly helped in minimizing the number of experiments, four mathematical models were derived to evaluate the wear loss of all types of materials as a function with the time of tst, the load used and the tyoe of the material.
It was niticed that the effect of time on weight loss, was higher than the effect of load for the as cast AA6101
and AA7075, while the effect of load on the weight loss was higher than the effect of time in the as rolled condition for both alloys.