碳纤维增强聚醚醚酮(CF/PEEK)复合材料广泛应用于航空航天,医疗器械,和汽车行业,以其卓越的机械性能和耐高温性而闻名。尽管有这些优势,动态载荷条件下CF/PEEK的热机械耦合行为尚不清楚。本研究旨在探讨CF/PEEK在高应变率下的热机械耦合效应。采用霍普金森杆冲击测试和扫描电子显微镜(SEM)进行详细表征。我们的发现表明,温度的升高导致屈服强度的显着降低,峰值应力,和CF/PEEK的比能量吸收,而断裂应变没有显著影响。例如,在200°C,屈服强度,峰值应力,比能量吸收下降了39%,37%,38%,分别,与它们在20°C下的值相比。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,随着应变率的进一步增加,4000s-1以上,应变速率对屈服强度和峰值应力的增强作用逐渐减弱。在高速冲击条件下,温度和应变率的交互作用显著影响了CF/PEEK的力学性能。虽然应变率通常增强了这些性能,随着温度的升高,应变硬化对屈服强度的影响减弱,温度和应变率都有助于增加比能量吸收。微损伤机理分析表明,纤维与基体之间的界面脱粘和滑动在静态压缩下比在动态压缩下更为明显。从而降低了应力传递的效率。此外,较高的温度导致PEEK基质软化并表现出增加的粘弹性行为,进而影响材料的韧性和应力传递机制。这些见解具有重大的工程意义,特别是CF/PEEK复合材料的优化设计和在极端环境中的应用。
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-1, 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.