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Indexed by:期刊论文

Date of Publication:2019-03-01

Journal:PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES

Included Journals:SCIE、Scopus

Volume:107

Page Number:182-186

ISSN No.:1386-9477

Key Words:Boron nitride; Carbon nanotubes; Elastic moduli; III-V semiconductors; Molecular dynamics; Nanocomposites; Nitrides; Phonons; Thermal insulating materials; Yarn, Boron nitride nanotubes; Coupling strengths; High frequency phonons; High thermal conductivity; Mechanical and thermal properties; Molecular dynamics simulations; One-dimensional nanocomposites; Thermal interface materials, Thermal conductivity

Abstract:The mechanical and thermal properties of a novel one dimensional nanocomposite, a coaxial (10,0) carbon nanotube inside a (19,0) boron nitride nanotube (CNT@BNNT), are studied by molecular dynamics (MD) simulations. Results show that the CNT@BNNT composites possess excellent mechanical strength and high thermal conductivity, both of which are comparable to that of individual CNT. The calculated Young's Modulus is about 0.856 TPa and the critical strain and the maximum stress can be increased by increasing the inter-tube coupling strength while decreased by increasing the tube length. Due to its larger tube densities, the overall thermal conductivity of the CNT@BNNT arrays is estimated to be 2.36 times that of the CNT arrays when used as the thermal interface materials (TIMs) and also exhibits better thermal stability at high temperatures owing to the presence of the BNNT sheath. Compression stress leads to a decrease in the thermal conductivity of the CNT@BNNT, and the thermal conductivity drops rapidly near the critical strain. However, when the compression strain exceeds the critical one, the thermal conductivity changes slowly with further increase of the compression strain. Phonon spectrum demonstrates that high frequency phonons play a dominate role in the thermal conductivity of the CNT@BNNT nanocomposite.