Please wait a minute...
金属学报  2020, Vol. 56 Issue (5): 795-800    DOI: 10.11900/0412.1961.2019.00305
  本期目录 | 过刊浏览 |
金属Mg二阶锥面<c+a>刃位错运动特性的分子动力学模拟
李美霖1, 李赛毅1,2()
1.中南大学材料科学与工程学院 长沙 410083
2.中南大学有色金属材料科学与工程教育部重点实验室 长沙 410012
Motion Characteristics of <c+a> Edge Dislocation on the Second-Order Pyramidal Plane in Magnesium Simulated by Molecular Dynamics
LI Meilin1, LI Saiyi1,2()
1.School of Materials Science and Engineering, Central South University, Changsha 410083, China
2.Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410012, China
引用本文:

李美霖, 李赛毅. 金属Mg二阶锥面<c+a>刃位错运动特性的分子动力学模拟[J]. 金属学报, 2020, 56(5): 795-800.
Meilin LI, Saiyi LI. Motion Characteristics of <c+a> Edge Dislocation on the Second-Order Pyramidal Plane in Magnesium Simulated by Molecular Dynamics[J]. Acta Metall Sin, 2020, 56(5): 795-800.

全文: PDF(1661 KB)   HTML
摘要: 

采用分子动力学方法模拟金属Mg的二阶锥面<c+a>刃位错在温度为300 K下的运动过程,研究不同大小及方向的外加剪切应力作用下的位错运动特性和结构演化规律。结果表明,实际驱动位错运动的有效剪切应力低于外加剪切应力;位错运动速率随外加剪切应力的增大而线性增大,在同等剪切应力下,对应于c轴拉伸变形时的位错运动速率高于c轴压缩,相应的拖曳系数显著高于同等温度下基面和柱面刃位错。位错运动特性的拉-压非对称性本质上与外加剪切应力对扩展位错宽度的影响有关。

关键词 位错分子动力学滑移拖曳系数    
Abstract

Magnesium has a hcp lattice structure, in which insufficient independent slip systems are available to accommodate applied plastic deformation at room temperature. The ductility of Mg is intimately related to the fundamental behaviors of pyramidal <c+a> dislocations, which are the major contributor to c-axis strain. In this study, the motion of <c+a> edge dislocation on the second-order pyramidal plane in Mg under external shear stress of different magnitudes and directions are simulated by molecular dynamics at 300 K, and the motion and structural evolution of dislocations are studied. The results show that the effective shear stress causing dislocation motion is lower than the external applied one and the dislocation velocity increases linearly with increasing applied shear stress. Under the same level of external shear stress, the dislocation velocity in shearing leading to c-axis tension deformation is higher than that for shearing leading to c-axis compression, and in both cases the corresponding viscous drag coefficients are significantly higher than those for basal and prismatic edge dislocations at the same temperature. The tension-compression asymmetry of dislocation motion is essentially related to the effect of applied shear stress on the extended dislocation width.

Key wordsdislocation    molecular dynamics    slip    drag coefficient
收稿日期: 2019-09-16     
ZTFLH:  TG146.2  
基金资助:国家自然科学基金项目(51571213);湖南省自然科学基金项目(2017JJ2312)
作者简介: 李美霖,女,1991年生,硕士生
图1  刃位错运动模型示意图
图2  正剪切下有效剪切应力(τeff)和平均有效剪切应力(τˉeff)随外加剪切应力(τapp)的变化
图3  不同τapp (正剪切)下位错芯的位移(d)-时间(t)曲线
图4  正、负剪切时位错运动速率(v)随τˉeff的变化曲线
图5  不同τapp下的位错芯结构
图6  正、负剪切过程中扩展位错宽度(l)随τapp的变化
1 Pollock T M. Weight loss with magnesium alloys [J]. Science, 2010, 328: 986
doi: 10.1126/science.1182848 pmid: 20489013
2 Chen Z H. Wrought Magnesium Alloy [M]. Beijing: Chemical Industry Press, 2005: 48
2 陈振华. 变形镁合金 [M]. 北京: 化学工业出版社, 2005: 48
3 Liu B Y, Liu F, Yang N, et al. Large plasticity in magnesium mediated by pyramidal dislocations [J]. Science, 2019, 365: 73
doi: 10.1126/science.aaw2843 pmid: 31273119
4 Bertin N, Tomé C N, Beyerlein I J, et al. On the strength of dislocation interactions and their effect on latent hardening in pure magnesium [J]. Int. J. Plast., 2014, 62: 72
5 Jiang J J, Miao L, Liang P, et al. Computational Material Science—Design Practice Method [M]. Shanghai: Higher Education Press, 2010: 162
5 江建军, 缪 灵, 梁 培等. 计算材料学——设计实践方法 [M]. 上海: 高等教育出版社, 2010: 162
6 Bacon D J, Osetsky Y N, Rodney D. Chapter 88 dislocation-obstacle interactions at the atomic level [J]. Dislocations Solids, 2009, 15: 1
7 Groh S, Marin E B, Horstemeyer M F, et al. Dislocation motion in magnesium: A study by molecular statics and molecular dynamics [J]. Modell. Simul. Mater. Sci. Eng., 2009, 17: 075009
8 Fan H D, El-Awady J A. Towards resolving the anonymity of pyramidal slip in magnesium [J]. Mater. Sci. Eng., 2015, A644: 318
9 Fan H D, Wang Q Y, Tian X B, et al. Temperature effects on the mobility of pyramidal <c+a> dislocations in magnesium [J]. Scr. Mater., 2017, 127: 68
10 Obara T, Yoshinga H, Morozumi S.{11$\bar{2}$2}<$\bar{1}$$\bar{1}$23> slip system in magnesium [J]. Acta Metall., 1973, 21: 845
11 Meyers M A, translated by Zhang Q M, Liu Y, Huang F L, et al. Dynamic Behavior of Materials [M]. Beijing: National Defense Industry Press, 2006: 230
11 (Meyers M A著>, 张庆明, 刘 彦, 黄风雷等译. 材料的动力学行为 [M]. 北京: 国防工业出版社, 2006: 230
12 Mordehai D, Ashkenazy Y, Kelson I, et al. Dynamic properties of screw dislocations in Cu: A molecular dynamics study [J]. Phys. Rev., 2003, 67B: 024112
13 Olmsted D L, Hector L GCurtinJr, , et al. Atomistic simulations of dislocation mobility in Al, Ni and Al/Mg alloys [J]. Modell. Simul. Mater. Sci. Eng., 2005, 13: 371
14 Plimpton S. Fast parallel algorithms for short-range molecular dynamics [J]. J. Comput. Phys., 1995, 117: 1
15 Osetsky Y N, Bacon D J. An atomic-level model for studying the dynamics of edge dislocations in metals [J]. Modell. Simul. Mater. Sci. Eng., 2003, 11: 427
16 Kim K H, Jeon J B, Lee B J. Modified embedded-atom method interatomic potentials for Mg-X (X=Y, Sn, Ca) binary systems [J]. Calphad, 2015, 48: 27
17 Berendsen H J C, Postma J P M, van Gunsteren W F, et al. Molecular dynamics with coupling to an external bath [J]. J. Chem. Phys., 1984, 81: 3684
doi: 10.1063/1.448118
18 Fan H D, El-Awady J A, Wang Q Y. Towards further understanding of stacking fault tetrahedron absorption and defect-free channels—A molecular dynamics study [J]. J. Nucl. Mater., 2015, 458: 176
doi: 10.1016/j.jnucmat.2014.12.082
19 Cho J, Molinari J F, Anciaux G. Mobility law of dislocations with several character angles and temperatures in FCC aluminum [J]. Int. J. Plast., 2017, 90: 66
20 Thompson A P, Plimpton S J, Mattson W. General formulation of pressure and stress tensor for arbitrary many-body interaction potentials under periodic boundary conditions [J]. J. Chem. Phys., 2009, 131: 154107
doi: 10.1063/1.3245303 pmid: 20568847
21 Regazzoni G, Kocks U F, Follansbee P S. Dislocation kinetics at high strain rates [J]. Acta Metall., 1987, 35: 2865
22 Stukowski A. Visualization and analysis of atomistic simulation data with ovito-the open visualization tool [J]. Modelling Simul. Mater. Sci. Eng., 2010, 18: 015012
doi: 10.1093/nar/gky381 pmid: 29800260
23 Larsen P M, Schmidt S, Schiøtz J. Robust structural identification via polyhedral template matching [J]. Modell. Simul. Mater. Sci. Eng., 2016, 24: 055007
24 Hirth J P, Lothe J. Theory of Dislocations [M]. 2nd Ed., New York: John-Wiley, 1982: 73
25 Nabarro F R N. Dislocations in a simple cubic lattice [J]. Proc. Phys. Soc., 1947, 59: 256
doi: 10.1088/0959-5309/59/2/309
26 Kumar A, Morrow B M, McCabe R J, et al. An atomic-scale modeling and experimental study of <c+a> dislocations in Mg [J]. Mater. Sci. Eng., 2017, A695: 270
[1] 张哲峰, 李克强, 蔡拓, 李鹏, 张振军, 刘睿, 杨金波, 张鹏. 层错能对面心立方金属形变机制与力学性能的影响[J]. 金属学报, 2023, 59(4): 467-477.
[2] 韩卫忠, 卢岩, 张雨衡. 体心立方金属韧脆转变机制研究进展[J]. 金属学报, 2023, 59(3): 335-348.
[3] 韩冬, 张炎杰, 李小武. 短程有序对高层错能Cu-Mn合金拉-拉疲劳变形行为及损伤机制的影响[J]. 金属学报, 2022, 58(9): 1208-1220.
[4] 田妮, 石旭, 刘威, 刘春城, 赵刚, 左良. 预拉伸变形对欠时效7N01铝合金板材疲劳断裂的影响[J]. 金属学报, 2022, 58(6): 760-770.
[5] 郑士建, 闫哲, 孔祥飞, 张瑞丰. 纳米金属层状材料强塑性的界面调控[J]. 金属学报, 2022, 58(6): 709-725.
[6] 高川, 邓运来, 王冯权, 郭晓斌. 蠕变时效对欠时效7075铝合金力学性能的影响[J]. 金属学报, 2022, 58(6): 746-759.
[7] 杨秦政, 杨晓光, 黄渭清, 石多奇. 粉末高温合金FGH4096的疲劳小裂纹扩展行为[J]. 金属学报, 2022, 58(5): 683-694.
[8] 李海勇, 李赛毅. Al <111>对称倾斜晶界迁移行为温度相关性的分子动力学研究[J]. 金属学报, 2022, 58(2): 250-256.
[9] 郭昊函, 杨杰, 刘芳, 卢荣生. GH4169合金拘束相关的疲劳裂纹萌生寿命[J]. 金属学报, 2022, 58(12): 1633-1644.
[10] 武晓雷, 朱运田. 异构金属材料及其塑性变形与应变硬化[J]. 金属学报, 2022, 58(11): 1349-1359.
[11] 兰亮云, 孔祥伟, 邱春林, 杜林秀. 基于多尺度力学实验的氢脆现象的最新研究进展[J]. 金属学报, 2021, 57(7): 845-859.
[12] 安旭东, 朱特, 王茜茜, 宋亚敏, 刘进洋, 张鹏, 张钊宽, 万明攀, 曹兴忠. 奥氏体316不锈钢中位错与氢的相互作用机理[J]. 金属学报, 2021, 57(7): 913-920.
[13] 石增敏, 梁静宇, 李箭, 王毛球, 方子帆. 板条马氏体拉伸塑性行为的原位分析[J]. 金属学报, 2021, 57(5): 595-604.
[14] 梁晋洁, 高宁, 李玉红. 体心立方Fe中微裂纹与间隙型位错环相互作用的分子动力学模拟[J]. 金属学报, 2020, 56(9): 1286-1294.
[15] 李源才, 江五贵, 周宇. 纳米孔洞对单晶/多晶Ni复合体拉伸性能的影响[J]. 金属学报, 2020, 56(5): 776-784.