Nie Shuyan, Chen Liming, Yun Zhaoxin, Wang Jie, Pan Xin
College of Aerospace Engineering, Chongqing University, Chongqing 400030, China.
Polymers (Basel). 2024 Aug 14;16(16):2295. doi: 10.3390/polym16162295.
Carbon-fiber-reinforced polyetheretherketone (CF/PEEK) composites are widely utilized in aerospace, medical devices, and automotive industries, renowned for their superior mechanical properties and high-temperature resistance. Despite these advantages, the thermomechanical coupling behavior of CF/PEEK under dynamic loading conditions is not well understood. This study aims to explore the thermomechanical coupling effects of CF/PEEK at elevated strain rates, employing Hopkinson bar impact tests and scanning electron microscopy (SEM) for detailed characterization. Our findings indicate that an increase in temperature led to significant reductions in the yield strength, peak stress, and specific energy absorption of CF/PEEK, while fracture strain had no significant effect. For instance, at 200 °C, the yield strength, peak stress, and specific energy absorption decreased by 39%, 37%, and 38%, respectively, compared to their values at 20 °C. Furthermore, as the strain rate increased, the yield strength, peak stress, specific energy absorption, and fracture strain all exhibited strain-hardening effects. However, as the strain rate further increased, above 4000 s, the enhancing effect of the strain rate on the yield strength and peak stress gradually diminished. The interaction of the temperature and strain rate significantly affected the mechanical performance of CF/PEEK under high-speed impact conditions. While the strain rate generally enhanced these properties, the strain-hardening effect on the yield strength weakened as the temperature increased, and both the temperature and strain rate contributed to the increase in specific energy absorption. Microdamage mechanism analysis revealed that interface debonding and sliding between the fibers and the matrix were more pronounced under static compression than under dynamic compression, thereby diminishing the efficiency of stress transfer. Additionally, higher temperatures caused the PEEK matrix to soften and exhibit increased viscoelastic behavior, which in turn affected the material's toughness and the mechanisms of stress transfer. These insights hold substantial engineering significance, particularly for the optimization of CF/PEEK composite design and applications in extreme environments.
碳纤维增强聚醚醚酮（CF/PEEK）复合材料因其优异的机械性能和耐高温性，在航空航天、医疗器械和汽车工业中得到广泛应用。尽管具有这些优点，但CF/PEEK在动态载荷条件下的热机械耦合行为仍未得到充分理解。本研究旨在通过霍普金森杆冲击试验和扫描电子显微镜（SEM）进行详细表征，探索CF/PEEK在高应变率下的热机械耦合效应。我们的研究结果表明，温度升高导致CF/PEEK的屈服强度、峰值应力和比能量吸收显著降低，而断裂应变没有显著影响。例如，在200°C时，屈服强度、峰值应力和比能量吸收分别比20°C时的值降低了39%、37%和38%。此外，随着应变率的增加，屈服强度、峰值应力、比能量吸收和断裂应变均表现出应变硬化效应。然而，当应变率进一步增加，超过4000 s时，应变率对屈服强度和峰值应力的增强作用逐渐减弱。温度和应变率的相互作用显著影响了CF/PEEK在高速冲击条件下的力学性能。虽然应变率通常会增强这些性能，但随着温度升高，对应屈服强度的应变硬化效应减弱，温度和应变率都导致比能量吸收增加。微观损伤机制分析表明，纤维与基体之间的界面脱粘和滑动在静态压缩下比动态压缩下更为明显，从而降低了应力传递效率。此外，较高的温度导致PEEK基体软化并表现出增加的粘弹性行为，进而影响了材料的韧性和应力传递机制。这些见解具有重要的工程意义，特别是对于CF/PEEK复合材料在极端环境下的设计和应用优化。
