摘要本文为了研究α铁中富铜团簇如何影响螺型位错的运动，建立BCC-Fe模型，用ATOMSK软件构造螺型位错，使用分子动力学研究BCC-Fe中螺型位错的运动及其与铜沉淀间的相互作用。通过施加平行于螺型位错的位错线方向的应力，使得螺形位错在其滑移面上作滑移运动，研究了施加应力大小和系统温度对螺型位错的运动速度的影响。采用Fe-Cu-Ni三元多体势函数，模拟研究BCC-Fe中螺型位错与铜沉淀物的相互作用，重点探讨了Cu团簇对螺型位错运动性质的影响以及螺型位错对Cu团簇结构的影响。叙述位错理论知识，并介绍了分子动力学方法以及一些软件。通过对模拟结果进行分析，可以得出以下结论：87903

（1）在温度不变时，随着应力的增加，位错运动速度变快。

（2）在压力不变时，位错运动速度随温度的增加而变快。但当温度的增加到一定程度后，速度变化逐渐趋于平缓。

（3）团簇和螺型位错的相互作用影响了位错的运动。

（4）位错对Cu团簇结构的影响是：位错促进Cu团簇结构由体心立方结构(BCC)向面心立方(FCC)或密排六方结构(HCP)转变。

毕业论文关键词  α铁  螺型位错  Cu团簇  分子动力学

毕业设计说明书外文摘要

Title   Atomistic simulation of the Interactions between   Copper Precipitates and Screw Dislocation in BCC-Fe。

Abstract To understand the influence of rich copper precipitations on movement of screw dislocation inα-Fe, a BCC-Fe model with screw dislocation which is created by ATOMSK is developed in this paper。 Molecular dynamics simulation is used to study the movement of screw dislocation and the interaction between screw dislocation and copper precipitations。 The screw dislocation is forced to move on the slip plane by the applied stress, and effects of the applied stress and temperature are discussed。 Interaction between screw dislocation and copper precipitations is simulated using the Fe-Cu-Ni ternary body potential function, focusing on the influence of Cu clusters on screw dislocation motion and the structure transformation of Cu cluster caused by the slip of the dislocation。 Some simple dislocation theory, molecular dynamics method and some software are described。 From the simulation results，the following results are obtained : (1) at a certain temperature, the dislocation velocity increases with the applied stress; (2) applying certain stress, the dislocation velocity increases with the increasing of temperature and the slope of the dislocation velocity dependent on temperature decreases with the increasing of temperature; (3) copper precipitates attract screw dislocation and seriously affect the motion of dislocation; (4) he screw dislocation promotes structure transformation of Cu clusters from  body-centered cubic (BCC) to faced-centered cubic (FCC) or hexagonal closest packing（HCP)。

Keywords  α-Fe  Screw Dislocation  Copper Precipitates  Molecular Dynamics 

目   次

1  绪论 1

1。1  引言 1源-于,优Y尔O论U文.网wwW.youeRw.com 原文+QQ75201,8766

1。2  位错基本理论 1

1。3  位错与团簇相互作用的研究情况 5

1。3。1  临界切应力 5

1。3。2  位错对团簇结构的影响 6

2  分子动力学模拟 7

2。1  分子动力学模拟基本算法 7

2。2   系综