氧化锌纳米线弹性及其相关物理力学性能的尺寸和温度效应

项目名称： 氧化锌纳米线弹性及其相关物理力学性能的尺寸和温度效应

项目编号： No.10802071

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 杨利文

作者单位： 湘潭大学

项目金额： 23万元

中文摘要： 弹性是材料最基本的力学性能，其不仅直接反映了材料的硬度、塑性等重要 力学性能，而且决定了材料的德拜温度、比热及热传导等重要的物理特性。研究表明，当 材料尺度、外界温度和压力变化时，一维纳米结构的弹性模量不再是常量，其可能变大， 变小，还可能维持块体值不变。这种反常的力学行为，目前的理论解释争论激烈，其原子 起因仍不清楚。本项目以氧化锌纳米线为研究对象，从实验和理论两方面研究一维纳米结 构的弹性及其相关物理力学性能。理论上，把近期发展的局域键平均和键弛豫理论结合起 来，从键的形成、断裂、弛豫和振动的角度出发提出一新解析模型，从原子尺度解释和预 测一维纳米结构弹性及其相关物理力学性能的尺寸和温度效应；实验上，通过水热合成法 制备尺寸和形状可控的氧化锌纳米线，采用纳米压痕技术和变温拉曼光谱表征其力学性能 以及外界条件对力学性能的影响。最终，我们把理论与实验相结合，为低维纳米材料力学 性能的研究提供理论依据。研究成果已经以学术论文的形式在Chem. Commun., J. Mater. Chem., Appl. Phys. Lett., J. Phys. Chem. C等期刊发表论文18篇。

中文关键词： ZnO纳米线;弹性;尺寸效应;温度效应;BOLS理论

英文摘要： Elasticity is one of the key elemental parameters in materials science, which is not only directly related to the fundmental mechanical performance, but also some important physical properties of a material, such as hardness, extensibility, Debye temperature, specific heat and thermal conductivity. Traditionally, the elastic modulus in a bulk materials is deemed as constant at a given temerature. However, with the miniaturiztion of a solid down to nanometer scale, the elastic modulus of one dimensional nanostructure(1D) is no longer constant but changes with the size, temperature and pressure. Measurements have reavealed surpringly that the value of elastic modulus changes in three ways: elevation, depression, or retention as the size is reduced. Unfortunately the current theoretical explanation, especially the atomic origin behind the intriguing mechanical behavior of 1D nanostructure is yet unclear. In this project, we will investigate the elasticity and its derivative mechanical properties of 1D nanostructure from both theories and experiments according to the results of ZnO nanowires. Theoritically, we expect to propose a new analytical solutions for explaining and predicting the size and temperatue effect of the elasticity and its derivative mechanical properties from the perspective of bond formation, dissociation, relaxation, and vibration by combining the recently developed local bond average (LBA)approach and bond-order-length-strength (BOLS) correlation theory. Experimently, we expect to fabricate ZnO nanowires with controllabe size and shape via hydrothermal synthesis, explore its mechanical properties and the effect of outer stimulus such as temperature and pressure on the latter via nano-indentation technique and temperature-related Raman spectroscopy. Finally, we expect to provide some useful theoritical rules for the research of mechanical properties in low dimensional nanometerials through summarizing and subliming our results.The project has derived 18 journal publications, including Chem. Commun., J. Mater. Chem., Appl. Phys. Lett., J. Phys. Chem. C, etc.

英文关键词： ZnO nanowires;Elasticity;Size effect; temperature effect; BOLS theroy