The effect of applied pressure on fracture surface and tensile properties of nickel coated continuous carbon fiber reinforced aluminum composites fabricated by squeeze casting

Composite specimens were consolidated using squeeze casting method under 30, 50 and 70 MPa applied pressures. Nickel coated polyacrylonitrile (PAN) based carbon fibers with a mean volume fraction of about 20% were used as reinforcement and the effect of applied pressure and coating layer were evaluated by studying the microstructure, fracture surface and tensile properties of the composite samples. The results indicate that presence of nickel coating on the carbon fibers improves the tensile strength of the composites, significantly. This seems to be the result of the effect of nickel layer on improving the wettability and also protecting the fibers against reaction with liquid aluminum during processing the composite. The appropriate applied pressure for preparing the composite samples was achieved to be about 30 MPa. Higher pressures demonstrated damage in distribution of the fibers and also caused separation of nickel coating layer.