摘要研究表明，Al-Mg合金是由大量晶粒组成的多晶体，层错是其材料塑性变形的重要本征参数，对金属及合金的变形机制和力学行为有重要影响。而层错的影响又靠层错能的大小来表征，因此，本文将对Al-Mg合金的层错能进一步研究。67467

本文采用EAM-Liu势，研究纯Al不同层错类型的层错能的差异及弛豫前后层错能的差异；纯Al加入一个镁原子后，镁原子的在晶体中的不同站位对层错能的影响；以及镁的含量对合金层错能的影响。

结果表明，（1）对纯Al来说不同类型的层错结构模型的层错能，经弛豫后都普遍降低；孪生型层错的层错能明显小于内禀型和外禀型层错的层错能；内禀型层错和外禀型层错的层错能相差不大。（2）在纯Al中加入一个镁原子，Mg原子的占位不同对无论是弛豫或者未弛豫晶体的层错能的影响都很微小。（3）对于I类型和T类型的层错结构模型，其层错能随着Mg原子含量的增加而降低。而对于E类型的层错，其层错能随着Mg原子含量的增加而升高。

毕业论文关键词  Al-Mg合金，层错能，势函数，EAM势，弛豫

毕业设计说明书（论文）外文摘要

Title    Simulated calculation of stacking fault energy   for Al-Mg alloy on the atomic scale                                                 

Abstract

    Studies have shown that aluminum magnesium alloy is made up of large grain polycrystal, fault is the important eigen parameters of plastic deformation of metals and alloys had important effect on the deformation mechanism and mechanical behavior. And the influence of the fault is characterized by the size of the fault can, therefore, this article will be on Al - Mg alloy layer fault can further research.The EAM - Liu potential, this paper studies the pure Al layer fault type of fault can be different differences and relaxation and dislocations that can; After joining a magnesium atom of pure Al, mg atoms in crystals in different position of fault can influence; And the content of magnesium on alloy layer can be influence by mistake.Results show that (1) different types for the pure Al layer structure model of fault can be wrong, after relaxation are generally lower; Twin type wrong layer type fault can be significantly less than intrinsic and external talents can wrong layer type wrong; the value of energy for Intrinsic fault and Extrinsic fault is similar. (2) when add a magnesium atom in pure Al, different Mg atoms placeholder have little effect on neither relaxed or unrelaxed stacking fault energy. (3) for the I type and T type of fault structure model, the fault can be reduced with the increase of Mg content of atom. For the E type of fault, the fault can be increased with the increase of the content of Mg atoms.

Keywords  Al-Mg alloy,  stacking fault energy,  potential function,  EAM potential,   relaxed  

目  次

1  绪论 1

1．1  课题研究背景及目的 1

1.2  研究现状 2

1.3  本课题研究目的与目标 3

2  Al-Mg势函数 4

2.1  势函数简介 4

2.2  EAM势 4

2.3  MEAM势 5

2.4   Al-Mg合金的势函数 6

2.5  本文使用的势函数