Effect of Temperature on the Mechanical Behavior of CF / PEEK Under Different Loads

ABSTRACT As the core structural material for light‐weighting in aerospace and other engineering fields, the actual service performance of composites is often subject to extreme temperatures and complex working conditions. Considering the effects of the service temperature of commercial aircraft from −54°C to 127°C and the matrix glass transition temperature (143°C), this paper systematically investigates the mechanical response of carbon‐fiber‐reinforced polyether‐ether‐ketone (CF/PEEK) composites over a wide range of temperatures (−60°C to 300°C). The results show that the bearing capacity of fibers and matrix is different under different loads, and the matrix‐dominated conditions (shear) are more sensitive to temperature changes, and the strength decay is significantly faster than that of the fiber‐dominated conditions (tension and compression). However, when the ambient temperature > , the compressive strength decay rate increases dramatically due to the weakening of the lateral support of the matrix to the fibers under compression. Post‐experimental specimen fracture observations indicate that the failure mode of CF/PEEK tends to be brittle at low temperatures. As the temperature increases, the CF/PEEK failure mode tends to be tougher due to the degradation of matrix mechanical properties and the weakening of the fiber‐matrix interface bonding. is the critical temperature for the transition of the CF/PEEK failure mode at high temperatures. Therefore, temperature protection should be emphasized for CF/PEEK structures under compression/shear loading, and special attention needs to be paid to the risk of steep performance degradation due to the phase transition of the matrix near .