A novel theoretical model for predicting the optimum number of layers of multiwall carbon nanotube for reinforcing iron and molecular dynamics investigation of the failure mechanism of multi-grained matrix

R Ishraaq and M Rashid and SM Nahid, COMPUTATIONAL MATERIALS SCIENCE, 196, 110558 (2021).

DOI: 10.1016/j.commatsci.2021.110558

Carbon nanotube (CNT) reinforced metal matrix composites have been the focus of researchers due to their high load-bearing capacity. Among single and multi-wall carbon nanotubes (MWCNT), the latter are preferred by manufacturers and engineers for making composites due to their economic feasibility of synthesizing. However, the effect of number of layers along with other parameters of the reinforcing MWCNT must be understood before its industrial application. In this article, we developed a novel theoretical approach for predicting the variation of strength and stiffness of MWCNT reinforced iron composites (MWCNT-Fe) with the number of layers of the reinforcing MWCNT and validated the prediction with a series of Molecular dynamics (MD) simulations. Our analysis revealed that for every addition of two extra layers, the strength and stiffness of the composite increase 9.8% and 7.2% respectively up to eight layered MWCNT and then becomes saturated. We also employed MD simulations for investigating the effect of grain boundary on the failure mechanism of CNT reinforced iron composites in contrast to previous studies. Our investigations revealed that instead of the matrix-fiber interface, the failure was initiated from the grain boundary and merges with the interface. The results in this study will not only help engineers and manufacturers choose optimal layered MWCNT for synthesizing composite for a specific application but also provide scientists a new method to model composites at nanoscale for predicting desired properties.

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