High Temperature Deformation and Fracture Behaviour of Continuous Alumina Fiber Reinforced Aluminum Composites with Different Fiber Orientation

Deformation and fracture behaviours were investigated in a continuous alumina fiber reinforced aluminum composite by tensile tests of specimens with different tensile axis orientations to the fiber axis at various temperatures from room temperature to 773 K. The orientation dependence of the tensile strength is well described by the maximum stress theory as well as by the Tsai-Hill's theory. Temperature dependences of strength σ c of composite in the direction of fiber axis, shear strength τ u of the matrix along the fiber axis and tensile strength σ u of the matrix in the direction normal to the fiber axis were determined. It is concluded that the decrease in the tensile strength of the composite with the rise of temperature is mainly due to the decrease in the τ u and σ u . It is suggested from the observation of fracture surfaces that the decrease in τ u and σ u at high temperatures is not only due to the decrease in strength of the matrix, but partly to the lowered shear and tensile strength of the matrix-fiber interface.