Effects of temperature distribution caused by energy accumulation on the bonding properties of carbon fiber composite components

Abstract Influence of temperature changes generated by plasma energy accumulation on bonding properties of carbon fiber composites (CFRP) was studied. The temperature field distribution on the bonding surface was built and tensile shear strength of the CFRP bonded components was evaluated. Results showed that the bonding strength was increased by 60.97% after the 5 min‐treatment. Because the energy accumulation could increase the local temperature of the bonding area to 195°C, a large amount of matrix resin was removed from the CFRP specimen. Then the surface wettability of the treated composite was greatly improved and the adhesive layer between the two bonded CFRP specimens became more similar to an interlayer in composites. The cohesive and interlaminar failure types occurred in the bonded component with the increased joint strength. Analysis of water contact angle, infrared spectroscopy, surface roughness and surface morphology indicated that the high‐surface free energy of the treated CFRP specimen and the mechanical interlocking between CFRP and adhesive caused by the decomposition of epoxy resin played a major role. When the treatment time further increased, the bonding area was severely damaged by the temperature of more than 215°C and then brittle fracture of the composites occurred, which was consistent with the subsequent decrease in bonding strength.