A molecular dynamics investigation for predicting the optimum fiber radius and the effect of various parameters on the mechanical properties of carbon nanotube reinforced iron composite

R Ishraaq and SM Nahid and S Chhetri and O Gautam and AM Afsar, COMPUTATIONAL MATERIALS SCIENCE, 174, 109486 (2020).

DOI: 10.1016/j.commatsci.2019.109486

Carbon nanotube (CNT) reinforced composites recently have drawn considerable attention from researchers due to their enormous potential in the automotive and space industries. However, knowledge of the composite's mechanical properties for different conditions is essential before its industrial application. In this study, the mechanical properties of CNT reinforced iron metal matrix composite (CNT-Fe MMC) is investigated by molecular dynamics (MD) simulation under uniaxial tension. Our investigation revealed that adding CNT into iron increases its tensile strength up to 58% and Young's modulus up to 40%. The mixture rule's accuracy to predict stress in the composite at the nanoscale is also studied. We developed a mathematical model to predict the pattern of change of the mechanical properties with the variation of CNT radius and validated this theoretical model with a series of MD simulations. We found that 2.5 angstrom is the optimum radius of CNT for manufacturing composites having maximum strength and stiffness. The strengthening effect of matrix volume percentage for different fiber radius and under different temperatures was also investigated. MD analysis also revealed the initiation and propagation of fracture. This study provides novel insights that should be useful in the fabrication of CNT-Fe MMC for strength-based mechanical applications.

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