بن امهاني، سمية2019-07-182019-07-182019-07-09http://dspace.univ-msila.dz:8080//xmlui/handle/123456789/15218A composite material with a metallic basis, of alloy (Al-7%.Wt Mg), is prepared by using stir casting technique, reinforced with (Al2O3) particles at various percentages (0 ،3 ،5 ،7 ،and 10 Wt.%). The result of test have shown an improvement in the value of hardness, the increasing in weight percentage of the reinforcement material (Al2O3) lead to increase the hardness, compared to the base alloy. The particles (Al2O3) are distributed in the base alloy, on the granular boundary, as shown by the optical microscope. Where the aluminum oxide, act as obstacle which restricts the movement of the dislocation, which leads to increased hardness of the composite material. In the first stage of the preparation of samples, the phase is formed α- Al(Mg). We also observed that x-ray peaks increase with the addition of alumina oxide particles. This explains that part of aluminum, existing in alumina particles, increases the quantity of aluminum existing, in the base alloy.frComposite material, (Al-7%.Wt Mg), (Technique Stir Casting), Alumina oxide (Al2O3), hardness Hv, x-ray, optical microscopy.Thesis