Abstract
The microstructure of injection molded polyetheretherketone reinforced with short glass and carbon fibers was investigated and its dependence on fiber volume fraction is discussed. The fracture toughness and fatigue crack propagation rate of neat polyetheretherketone and its composites were measured and are correlated with microstructural parameters. Failure mechanisms were observed by scanning electron microscopy of the fractured surfaces. The fracture properties are found to be anisotropic, when measured in different directions relative to the mould fill direction. The material's performance is only slightly affected by the addition of short fibers.