Coupling stiffening effect of carbon nanotubes on modulus of nanograined metals: Mechanism and multiscale modeling

A quantitative relationship between grain size and Young’s modulus of metal composites has not been established by considering the coupling effect of the reinforcements on microstructural deformation. The objective of this study is to investigate the mechanism of deformation coordination between the carbon nanotube and the composite microstructure using molecular dynamics simulations. Through the analysis of stress contributions from grain boundaries and grains, a grain size-dependent continuum model for the pure metal modulus is established. On this basis, a predictive model for the modulus of metallic composites is developed by considering the coupling deformation between carbon nanotubes and the grains. The proposed model is capable of accurately capturing the relationship between grain size and the modulus of metal composites. This study provides a guideline for microstructure-dependent multiscale modeling.