Temperature- and strain-rate-dependent tensile failure behavior of short-fiber-reinforced PEEK composites

This work presents an experimental investigation of the tensile failure behaviors of polyetheretherketone (PEEK), short carbon, and glass-fiber-reinforced PEEK composites at -30–100 °C and various strain rates (10⁻³–10³ s⁻¹). Quasi-static and dynamic tensile tests are conducted, and fracture morphology is characterized by performing scanning electron microscopy to reveal the mechanical properties and failure mechanisms of PEEK and its composites at different temperatures and strain rates. The results indicate that the tensile strength is highly sensitive to temperature and strain rate. At −30 °C and 100 °C, the strain rate sensitivity of the failure strain of the two composites is significantly reduced. In addition, compared with that at 25 °C, the energy absorptivity of PEEK composites decreases at high or low temperatures. Moreover, the primary failure mechanisms of the PEEK composites are interfacial debonding and fiber pull-out at high temperatures and fiber fracture at low temperatures.