FATIGUE BEHAVIOUR OF Al2O3 SHORT FIBRE REINFORCED ALUMINIUM ALLOY

The room temperature fatigue strengths of A1-7Si-0.6Mg and A1-SSi-3Cu-1Mg composites randomly reinforced with A1₂O₃ short fibres were determined using a stress ratio of 0.1, a frequency of 50 Hz. The fatigue strength of the composites under these testing conditions can be expressed by a single curve-fitting equation. The effect of surface roughness on fatigue strength was also studied and the results show that these composites are not sensitive to surface roughness. The orthogonal growth of cracks is an important fatigue fracture mechanism in these composites. The residual strength decreased as the fatigue load increased.