Dislocations, Plasticity, and Strain Hardening in Carbon Nanotubes

碳纳米管中的位错、塑性和应变硬化

• 批准号: 0528511
• 负责人: Daryl Chrzan
• 金额: --
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-15 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0528511&HistoricalAwards=false
• 关键词: Dislocations; Plasticity; Strain; Hardening; Carbon

Dislocations, Plasticity, an Strain Hardening in Carbon NanotubesD. C. ChrzanDepartment of Materials Science and EngineeringUniversity of CaliforniaBerkeley, CA 94720-1760AbstractCarbon nanotubes display unusually high tensile strengths and stiffnesses, and breaking stresses as high as 30 GPa have been reported. While the elastic properties of carbon nanotubes are well understood, the plastic properties of carbon nanotubes remain unsettled. Intriguingly, carbon nanotubes are expected to deform plastically through the nucleation of dislocation dipoles (Stone-Wales defects), the dissociation of these dipoles, and the subsequent motion of the dislocations. Estimates of the formation energy for Stone-Wales defects vary widely, perhaps because their formation energy is influenced by elastic interactions between the defects. We will use elasticity theory solutions for periodic dislocation arrays to analyze defect formation energies obtained from density functional theory based total energy methods. This analysis will yield core radii for the dislocations and ultimately, a transferable theory of dislocations in nanotubes. This theory can then be applied to model plasticity in carbon nanotubes under a variety of loading conditions.

碳纳米管中的位错、塑性、应变硬化 D． C. Chrzan 加州大学伯克利分校材料科学与工程系，CA 94720-1760 摘要碳纳米管表现出异常高的拉伸强度和刚度，据报道断裂应力高达 30 GPa。虽然碳纳米管的弹性特性已广为人知，但碳纳米管的塑性特性仍然悬而未决。有趣的是，碳纳米管预计会通过位错偶极子（斯通威尔士缺陷）的成核、这些偶极子的解离以及位错的后续运动而发生塑性变形。 Stone-Wales 缺陷的形成能估计差异很大，可能是因为它们的形成能受到缺陷之间弹性相互作用的影响。我们将使用周期性位错阵列的弹性理论解来分析从基于密度泛函理论的总能量方法获得的缺陷形成能量。 该分析将得出位错的核心半径，并最终得出纳米管位错的可转移理论。 然后可以将该理论应用于各种负载条件下碳纳米管的塑性模型。