Anisotropic Charpy impact behavior of novel interpenetrating phase composites

Composites provide improved combinations of mechanical properties of raw materials. Two novel interpenetrating phase composites (IPCs) have been fabricated by infiltrating unsaturated polyester resin and ZA8 zinc alloy into porous stainless steel fiber preforms, respectively. In this study, Charpy impact tests are conducted to characterize the impact properties. The fractographs are examined to distinguish toughening mechanisms. The structures and the impact properties present anisotropy for both IPCs. The impact toughness increases with increasing fiber fraction. Compared with the metal-resin IPCs in-plane direction, higher impact absorbing energy and toughness are observed in through-thickness direction. The metal-metal IPCs in longitudinal direction present slightly higher impact toughness than those in radial direction. The anisotropic impact properties are more obvious in metal-resin IPCs. The fracture surfaces of the two novel IPCs exhibit ductile-brittle characteristics. Fiber necking and fracture, pullout and fracture of the matrix are the main mechanisms of impact fractures of the novel IPCs.