Nanomechanical behavior of β-SiC nanowire and CNT/β-SiC nanowire junction; molecular dynamics simulations = 분자동역학 전산모사를 이용한 β-SiC nanowire 와 CNT/β-SiC nanowire 접합의 기계적 특성 평가

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Molecular dynamics (MD) simulations based on Tersoff potential have been performed to study the mechanical properties of a β-SiC nanowire and CNT/β-SiC nanowire under tension with a constant strain rate. A tension, proportional to the deformation within Hook’s law, eventually led to a breaking of a β-SiC nanowire and CNT/SiC junction. With the diameter and axis direction of a β-SiC nanowire and simulation temperature, we calculated the curve of strain energy vs. strain. In addition, the elastic modulus of the β-SiC nanowire and a CNT/SiC junction was determined from the curve of the strain energy vs. strain. During tensile loading, the elastic modulus of the β-SiC nanowire and a CNT/SiC junction was generally decreasing with temperature and tended to increase with diameter of the nanowire. The axis of Young’s modulus (279 to 770 GPa) of the β-SiC nanowire lay along the <111> direction was considerably higher than that (110 to 200 GPa) of the β-SiC nanowire with the axis in the <001> direction. Our simulation result with the nanowire with axis of the <111> direction was in good agreement with the experimental data which was within the range from 316 to 890 GPa. In the case of a CNT/SiC junction, also we investigated the Young’s modulus. The CNT/[111] β-SiC nanowire (241 to 392.3 GPa) was considerably higher than that (105.2 to 299.6 GPa) of the CNT/[001] β-SiC junction. The [111] Young’s modulus was higher than that of the [001] orientation in a β-SiC nanowire and a CNT/β-SiC nanowire junction. We also observed that the β-SiC nanowire formed one atomic chain consisting of Si-Si bonds near the necking occurrence area; the length of the atomic chain increased with strain and eventually the nanowire fractured. This is because the bond strength of Si-Si is weaker than those of Si-C and C-C. Due to the superior mechanical properties of the CNT, tension properties in the CNT/β-SiC nanowire junction closely depended on that of β-SiC nanowire.
Advisors
Lee, Hyuch-Moresearcher이혁모researcher
Description
한국과학기술원 : 신소재공학과,
Publisher
한국과학기술원
Issue Date
2004
Identifier
238316/325007  / 020023168
Language
eng
Description

학위논문(석사) - 한국과학기술원 : 신소재공학과, 2004.2, [ iii, 63 p. ]

Keywords

기계적 특성; Tersoff 포텐셜; 탄성계수; MOLECULAR DYNAMICS (MD) SIMULATIONS; TERSOFF POTENTIAL; MECHANICAL PROPERTIES; ELASTIC MODULUS; 분자동역학 전산모사

URI
http://hdl.handle.net/10203/51602
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=238316&flag=dissertation
Appears in Collection
MS-Theses_Master(석사논문)
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