有限温度下位错的芯结构与Perierls应力的研究

项目名称： 有限温度下位错的芯结构与Perierls应力的研究

项目编号： No.11304403

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 王锐

作者单位： 重庆大学

项目金额： 25万元

中文摘要： 晶体材料温度的微观表现为晶格振动。材料中存在着大量的位错缺陷，晶格振动的剧烈程度必然对位错性质有着重要的影响。长期以来，关于位错的各种理论模型都不包含温度，无力研究有限温度下与位错结构有关的诸多性质。本项目结合晶格位错理论和基于密度泛函理论计算的声子谱，在理论上获得研究有限温度下位错性质的方法,计算广义层错能、位错芯结构、Peierls应力等性质随温度的变化规律，讨论不同温度下的位错运动机制，进而揭示在有限温度下位错芯重构和位错扭折激发的热力学机制。

中文关键词： 温度；晶格动力学；位错方程；Peierls应力；第一性原理

英文摘要： Temperature in crystalline materials takes the form of the lattice vibrations in microcosmic. There are many defects of dislocation in materials, and the magnitude of lattice vibrations must have an important effect on the properties of dislocation. Over the years, the various theoretical models of dislocation have not include the temperature effects, so the properties related to the structure of dislocation at finite temperature can not be investigated. In this project, we will combine with the lattice theory of dislocation and the phonon spectra from the calculation based on the density functional theory to obtain the method of investigating the properties of dislocation at finite temperature. We will calculate the temperature dependence of the generalized stacking fault energy, the core structure of dislocation, and Peierls stress et.al., and discuss the mechanism of the dislocation mobilities under different temperature conditions. Furthermore, we will try to reveal the thermodynamic mechanism for the reconstruntions of dislocation core and the kink excitation of dislocation at finite temperature.

英文关键词： Temperature；Lattice Dynamics；Dislocation equation；Peierls stress；First-priciples