Effects of interphase, CNT waviness and temperature on the Young's modulus of CNT/metal composites

Lightweight designs in the aerospace field require materials with high stiffness to maintain functionality, which has significantly stimulated the demand for effective characterization and evaluation of Young's modulus. In this study, beginning with the existing interfacial layer theory, micromechanical modeling of the interphase was conducted in combination with electron microscopy images. Then, a comprehensive analytical model of Young's modulus of CNT/metal composites taking into account the effects of interphase and CNT waviness was developed. Finally, based on the relation between Young's modulus and the cohesive energy, the developed analytical model was extended to a wide range of temperatures. The comparisons between model-predicted results and available experimental and simulation results at room temperature and elevated temperatures were carried out to verify the validity of the proposed models. And as expected, to achieve a more accurate prediction, considering the effects of interphase and CNT waviness are critically essential. The developed analytical model provides a simple way to predict temperature dependent Young's modulus of CNT/metal composites, helping to save time and resources by reducing wide temperature domain testing. Moreover, detailed parametric studies were systematically performed to gain helpful insights into the sensitivity of nanocomposite modulus to the interfacial properties at different temperatures.