TENSILE AND FRACTURE CHARACTERISTICS OF A SIC- PARTICLE-REINFORCED ۷۰۷۵ ALUMINIUM ALLOY

Fracture behavior of a ۷۰۷۵ aluminium alloy reinforced with ۱۵ Vol%. SiC particles was studied after T۶ and annealing heat treatments under uniaxial tensile loading at room temperature. The scanning electron microscopy of fractured surfaces and EDS analysis showed:, that fracture mechanism changed from due mainly to fractured particle in T۶ condition to interface decohesion in samples in annealed state. Different fracture mechanisms in annealed and T۶ conditions can be ascribed mainly to the significant difference in the stress concentration levels around the particles. In T۶ condition, very high local stress sufficient to cause fracture of particle can be generated during loading, while the presence of large precipitates at the particle/matrix interface produced interface decohesion leading to final fracture in the annealed state.

Keywords:

particle , reinforced composite , particle fracture , interface decoheion , particle/matrix interface