EXPERIMENTAL-STUDY OF THE EFFECT OF THE ANISOTROPY OF ORIENTATION OF THE REINFORCING PARTICLES ON THE TENSILE PROPERTIES OF ALUMINUM-MATRIXCOMPOSITES REINFORCED WITH ALPHA-ALUMINA PLATELETS

This paper is focused on the effect of the distribution of the orienta tion of reinforcing particles having the shape of platelets on the ten sile properties of aluminium matrix composites. To obtain different di stributions of orientation, the initially isotropic composites were su bmitted to two secondary fabrication processes: rolling and extrusion. The conventional tensile tests performed on the isotropic, rolled and extruded composites showed that rolling and extrusion modify the init ial work hardening rate, the flow behaviour at high strains and the st rains to failure of the composites. The decrease in the initial work h ardening rate of the rolled and extruded composites was attributed to the alignment of the platelets along the rolling or extrusion directio n, which reduces the forest interaction contribution to the work harde ning. The increased strains to failure were attributed to the fact tha t the three types of composite are characterized by three different da mage mechanisms, as was shown by in-situ tensile tests performed in a scanning electron microscope. These mechanisms do not have the same in cidence on the ductility of the composites.