الفهرس 
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Abstract
Aluminum based metal matrix composites MMc have been extensively studied in the last decades.these composites exhibit attractive physical and mechanical properties, such as high specific modulus, good strength, long fatigue life, superior wear resistance, and improved thermal stability. such properities allow these composites to have numerous applications in the aerospace, automobile, electrical, desalination, and military industries. in the present study, A356 aluminum alloy metal matrix composite MMC reinforced with various volume fractions 5.705, and 10 vol.% of silicon carbide particle SiC are fabricated by stir casting at various stirring speeds 300,600, and 90 rpm for 10minutes at 720C the effect of SiC content on density, porosity, hardness, modulus of elasticity, 0.2% offset compression proof stress maximum compressie stress, wear resistance, strain hardening rate at low strains and microstructure of all samples are investigated. it is observed that, increasing the stirring speed to 900 rmp, enhances homogeneity of SiC distribution in the A 356 matrix alloy. density measurement show that the samples contion low porosity, which increases with increasing volume fraction of SiC. the hardness, 0.2% offest compression proof stress, and compressive stress at maximum strain increase with increasing volume fraction of SiC at 10vol.% SiC, vickers hardness number is 16% greater than that of the matrix alloy. moreover, at 5vol.% SiC, the modulus of elasticity is 18% greater than that matrix alloy. beside, at 10vol.% SiC, 0.2% offest compression proof stress is 63% greater than that of the matrix alloy, and compressive stress at maximum strain achieved for present composites is about 40% greater than that of the matrix alloy. the strain hardening rate increases progressively with the increase of the hard SiC content. however, such increase becomes much slower at values of SiC contents higher than 7.5%. in general, the rate of strain hardening decrease of applied strain. furthermore, the results of wear test show that, the wear resistance of MMC increases with increasing volume fraction of SiC.