摘要目前普遍我们接受的理论认为纯铜的层错能大约是孪晶形成能的两倍，和掺杂金属元素是降低材料层错能的有效办法。本课题基于第一性原理对铜和铜合金的层错和孪晶模型进行模拟计算，说明了掺杂金属元素降低铜层错和孪晶形成能的原因。主要讨论了在有掺杂元素的情况下铜的层错或孪晶界表面处的溶质偏聚现象（基于铃木效应的讨论）和在有掺杂的情况下层错能是孪晶形成能的两倍关系是否成立。为此，本论文要计算大约10种掺杂元素在Cu孪晶界的偏聚效应和其孪晶形成能的大小。并与其在层错上的作用相比较，比较其二倍关系在掺杂境况下是否发生变化，并且总结其变化的规律。用准确的模拟数据说明了在有掺杂的情况下铜的层错能是孪晶形成能的2倍关系不成立，并且其偏离程度随掺杂原子的种类不同而不同。87843

毕业论文关键词  层错能 层错 孪晶 孪晶形成能 第一性原理 铃木效应

毕业设计说明书外文摘要

Title    The doping of metal influence Cu layer and twin formation energy 

Abstract At present generally accepted by us according to the theory of pure copper stacking fault energy is about twin formation of two times, and metal element doping is effective way to reduce material stacking fault energy。Based on the first principles, this paper simulated the layer and twin model of copper and copper alloys, and explained the reasons for the reduction of the copper layer and the formation energy of the twins。Mainly discusses the doping copper stacking fault or twin boundaries at the surface of the solute segregation phenomenon (based on the Suzuki effect discussion) and the doping of the lower fault can is twin formation to twice the relationship is established。To this end, this thesis will calculate the segregation effect and the size of the twin formation energy of about 10 kinds of doping elements in the Cu twin boundary。And compared with the effect of the layer on the wrong, the comparison of the two times in the case of the doping changes, and summarizes the law of its change。The accurate simulation data shows that the 2 times of the formation energy of the twin formation energy is not formed in the layer of the doped copper, and the degree of deviation varies with the type of the doped atom。源-于,优Y尔E论W文.网wwW.yOueRw.com 原文+QQ752018`766

Keywords  Stacking fault energy Stacking fault twin Twin formation energy DTF Suzuki 

目   次

1绪论 1

1。1铜的简介 1

1。2铜与铜合金 1

1。3铜中的层错与层错能 3

1。3。1堆垛层错 3

1。3。2层错能及广义层错能 4

1。3。2层错能对材料力学性能的影响 4

1。4铜中的孪晶与孪晶形成能 5

1。4。1孪晶 5

1。4。2孪晶对材料性能的影响 6

1。5铃木气团 7

1。6铜的层错与孪晶能的第一性原理计算 7

1。6。1 Born-Oppenheimer 近似 7

1。6。2 Hartree-Fock 近似算法 8

1。6。3密度泛函理论计算法 8

1。6。4 具体计算方法 8

1。7 本论文研究内容及意义