The effects of temperature and hygrothermal aging on the properties of CF/PA6 composite and its compression failure mechanisms

Carbon fiber reinforced polyamide composites have outstanding properties, but their applications are significantly affected by the service environment. This work evaluates the effects of temperature (25, 80, 140, and 200 degrees C) and hygrothermal conditions on the mechanical properties of CF/PA6 composite containing delamination damage, and studies its damage behaviors and failure mechanisms. After hygrothermal aging, recrystallization of PA6 improves the heat resistance of CF/PA6 composites, but water absorption reduces the interfacial strength of composites, resulting in the decrease of modulus and compressive strength (24% and 42%, respectively). With the increase in temperature, the compressive strength of CF/PA6 composites gradually decreases (from 132 MPa at 25 degrees C to 24 MPa at 200 degrees C), and the failure mode transitions from fiber fractures, interlayer shear fractures, delamination to kinking. In addition, the compressive failure process of CF/PA6 composites is divided into three stages: buckling, delamination bulging and kinking failure. Highlights Hygrothermal aging reduces the fiber/resin interface performance.<br /> Fiber fracture, interlayer shear and delamination convert to kinking failure.<br /> The failure process is divided into buckling, delamination and kinking