Effect of Hygrothermal Aging on Interlaminar Shear Strength of T700/TDE-85 Composite

The artificial accelerated hygrothermal aging test was conducted on the T700 carbon fiber/TDE-85 epoxy resin (T700/TDE-85) composite. The variation law of moisture absorption characteristics and interlaminar shear strength of the composite with aging time was investigated. The relationship between moisture absorption rate and interlaminar shear strength was analyzed. The surface and fracture morphology of the composite were observed. The results show that when aged for about 1 369 h, the composite reached the saturated moisture state with the absorption rate of 0.74%. The diffusion coefficient of water molecule in the composite was 5.6×10^-5 mm²·s^-1. The interlaminar shear strength of the composite decreased greatly with the increase of aging time at the initial aging stage, and then decreased slightly after the moisture absorption reached saturation. The interlaminar shear strength retention rate and moisture absorption rate had a linear relationship approximately. With the increase of aging time, the mode of crack propagation developed from intra-layer cracks to interlayer cracks.