Comparison of Wet and Hot Aging Resistance of T700 and T300 Carbon Fiber Strengthened Epoxy Resin Composites

Accelerated aging experiments of T700 and T300 carbon fiber/epoxy resin composites,as well as two types of composite/metal adhesive joints were carried out respectively for 70 d in a hot-wet environment with temperature of 70 ℃ and relative humidity of 85%.Mechanical property tests and nondestructive test (NDT) of the samples before and after aging were also performed.The results show that the hygrothermal environment did not change the failure modes of the two types of composite samples,but decreased slightly the longitudinal/lateral compressive strength and shear strength.For composite/metal joints,the hydrothermal environment could not bring about damage at the bonding interface,but could bring down its shear strength.The mechanical properties of T700/epoxy resin composite were equivalent to those of T300/epoxy resin composite before aging,while the former was superior to the latter in respect to the property conservation percentage after aging for 70 d.