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纳米多晶铜的超塑性变形机理的分子动力学探讨

闻鹏 陶钢 任保祥 裴政

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纳米多晶铜的超塑性变形机理的分子动力学探讨

闻鹏, 陶钢, 任保祥, 裴政

Superplastic deformation mechanism of nanocrystalline copper: a molecular dynamics study

Wen Peng, Tao Gang, Ren Bao-Xiang, Pei Zheng
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  • 在聚能装药爆炸压缩形成射流的过程中, 伴随着金属药型罩的晶粒细化, 从原始晶粒30-80 μm细化到亚微米甚至纳米量级, 从微观层面研究其细化机理和动态超塑性变形机理具有很重要的科学意义. 采用分子动力学方法模拟了不同晶粒尺寸下纳米多晶铜的单轴拉伸变形行为, 得到了不同晶粒尺寸下的应力-应变曲线, 同时计算了各应力-应变曲线所对应的平均流变应力. 研究发现平均流变应力最大值出现在晶粒尺寸为14.85 nm时. 通过原子构型显示, 给出了典型的位错运动过程和晶界运动过程, 并分析了在不同晶粒尺寸下纳米多晶铜的塑性变形机理. 研究表明: 当晶粒尺寸大于14.85 nm时, 纳米多晶铜的变形机理以位错运动为主; 当晶粒尺寸小于14.85 nm时, 变形机理以晶界运动为主, 变形机理的改变是纳米多晶铜出现软化现象即反常Hall-Petch关系的根本原因. 通过计算结果分析, 建立了晶粒合并和晶界转动相结合的理想变形机理模型, 为研究射流大变形现象提供微观变形机理参考.
    In the process of the generation of jet formed by the shaped charge explosive compression, the grain of the metal liner is refined from 30-80 μm down to sub-micron or nanometer level. There is a strong scientific significance for studying the mechanism of grain refinement and dynamic superplastic deformation at a micro level. The main contents of this study are as follows. Firstly, the models of nanocrystalline copper with the grain sizes of 7.17, 9.11, 12.55, 14.85, 18.38 and 22.48 nm are established using the Voronoi geometrical construction method, and these models are relaxed in 100 ps to the equilibrium state at 293 K. Then, the tensile deformation processes of nanocrystalline copper at various grain sizes are simulated by using the molecular dynamics method. The strain increases to 0.2 gradually at a strain rate of 2×109/s. Based on the data output, the stress-strain curves at different grain sizes are gained and the corresponding values of the averaged flow stress are calculated. The results show that the average flow stress exhibits the maximum at a grain size of 14.85 nm. Finally, the primary deformation process of nanocrystalline copper is displayed by analyzing the atomic configuration evolvement. When the grain size is 22.48 nm, the typical dislocation motion is found and there are a huge number of dislocations in the deformation process. However, the number of dislocations decreases sharply at the grain sizes of 14.85 nm and 9.11 nm, and the grain-boundary motion is visible at these small grain sizes. The most significant work is that the deformation mechanisms of nanocrystalline copper at different grain sizes are analyzed in detail. The results indicate that the dislocation motion dominates the deformation process when the grain sizes of nanocrystalline copper are larger than 14.85 nm. As the grain sizes decrease below 14.85 nm, the grain-boundary sliding and rotation become a dominant deformation mechanism. This change of deformation mechanism is the fundamental reason for softening, which is so-called reverse Hall-Petch relationship. On the basis of previous study and this molecular dynamics simulation, combining the grain coalition and the grain-boundary rotation, an ideal deformation mechanism model is established at small grain sizes, which provides the microcosmic deformation mechanism reference for the large strain deformation of the jet.
    • 基金项目: 江苏省普通高校研究生科研创新计划(批准号:KYLZ_0325)资助的课题.
    • Funds: Project supported by the Research and Innovation Program for Postgraduate of the Higher Education Institution of Jiangsu Province, China (Grant No. KYLZ_0325).
    [1]

    Tao G, Chen H, Shen Q C 2008 Explosion and Shock Waves 28 336 (in Chinese) [陶钢, 陈昊, 沈钦灿 2008 爆炸与冲击 28 336]

    [2]

    Tian W H 2003 Mater. Sci. Eng. A 350 160

    [3]

    Murr L E, Trillo E A, Pappu S 2002 J. Mater. Sci. 37 3337

    [4]

    Trillo E A 2002 Mater. Charact. 48 407

    [5]

    Chokshi A H, Meyers M A 1990 Scr. Metall. 24 605

    [6]

    Li J C M 1961 J. Appl. Phys. 32 525

    [7]

    Murr L E 1997 Mater. Sci. Eng. A 222 118

    [8]

    Meyers M A, Nesterenko V F, LaSalvia J C, Xue Q 2001 Mater. Sci. Eng. A 317 204

    [9]

    Meyers M A, Mishra A, Benson D J 2006 JOM 58 41

    [10]

    Daw M S, Baskes M I 1983 Phys. Rev. Lett. 50 1285

    [11]

    Schiøtz J, Karsten W J 2003 Science 301 1357

    [12]

    Garritt J T, Shreevant T, Jonathan A Z, David L M 2012 J. Mech. Phys. Solids 60 471

    [13]

    Zhang H W, Fu Y F, Zheng Y G, Ye H F 2014 Phys. Lett. A 378 736

    [14]

    Yuan L, Jing P, Liu Y H, Xu Z H, Shan D B, Guo B 2014 Acta Phys. Sin. 63 016201 (in Chinese) [袁林, 敬鹏, 刘艳华, 徐振海, 单德彬, 郭斌 2014 物理学报 63 016201]

    [15]

    He A M, Shao J L, Wang P, Qin C S 2010 Acta Phys. Sin. 59 8836 (in Chinese) [何安民, 邵建立, 王裴, 秦承森 2010 物理学报 59 8836]

    [16]

    Ma W, Lu Y W 2013 Acta Phys. Sin. 62 036201 (in Chinese) [马文, 陆彦文 2013 物理学报 62 036201]

    [17]

    Kadau K, Germann T C, Lomdahl P S, Holian B L, Kadau D, Entel P, Kreth M, Westerhoff F, Wolf D E 2004 Metall. Mater. Trans. A 35 2719

    [18]

    Keblinski P, Wolf D, Phillpot S R, Gleiter H 1999 Scr. Mater. 41 631

    [19]

    Chen D 1995 Comput. Mater. Sci. 3 327

    [20]

    Hoover W G 1989 Phys. Rev. A 40 2814

    [21]

    Mishin Y, Mehl M J, Papaconstantopoulos D A, Voter A F, Kress J D 2001 Phys. Rev. B 63 224106

    [22]

    Li D, Wang F C, Yang Z Y, Zhao Y P 2014 Sci. China: Phys. Mech. Astron. 57 2177

    [23]

    Honeycutt J D, Andersen H C 1987 J. Phys. Chem. 91 4950

    [24]

    Yuan F P 2012 Sci. China: Phys. Mech. Astron. 55 1657

    [25]

    Kumar K S, Swygenhoven H V, Suresh S 2003 Acta Mater. 51 5743

    [26]

    Liao X Z, Srinivasan S G, Zhao Y H, Baskes M I, Zhu Y T 2004 Appl. Phys. Lett. 84 3564

    [27]

    Wang Y M, Ma E, Chen M W 2002 Appl. Phys. Lett. 80 2395

  • [1]

    Tao G, Chen H, Shen Q C 2008 Explosion and Shock Waves 28 336 (in Chinese) [陶钢, 陈昊, 沈钦灿 2008 爆炸与冲击 28 336]

    [2]

    Tian W H 2003 Mater. Sci. Eng. A 350 160

    [3]

    Murr L E, Trillo E A, Pappu S 2002 J. Mater. Sci. 37 3337

    [4]

    Trillo E A 2002 Mater. Charact. 48 407

    [5]

    Chokshi A H, Meyers M A 1990 Scr. Metall. 24 605

    [6]

    Li J C M 1961 J. Appl. Phys. 32 525

    [7]

    Murr L E 1997 Mater. Sci. Eng. A 222 118

    [8]

    Meyers M A, Nesterenko V F, LaSalvia J C, Xue Q 2001 Mater. Sci. Eng. A 317 204

    [9]

    Meyers M A, Mishra A, Benson D J 2006 JOM 58 41

    [10]

    Daw M S, Baskes M I 1983 Phys. Rev. Lett. 50 1285

    [11]

    Schiøtz J, Karsten W J 2003 Science 301 1357

    [12]

    Garritt J T, Shreevant T, Jonathan A Z, David L M 2012 J. Mech. Phys. Solids 60 471

    [13]

    Zhang H W, Fu Y F, Zheng Y G, Ye H F 2014 Phys. Lett. A 378 736

    [14]

    Yuan L, Jing P, Liu Y H, Xu Z H, Shan D B, Guo B 2014 Acta Phys. Sin. 63 016201 (in Chinese) [袁林, 敬鹏, 刘艳华, 徐振海, 单德彬, 郭斌 2014 物理学报 63 016201]

    [15]

    He A M, Shao J L, Wang P, Qin C S 2010 Acta Phys. Sin. 59 8836 (in Chinese) [何安民, 邵建立, 王裴, 秦承森 2010 物理学报 59 8836]

    [16]

    Ma W, Lu Y W 2013 Acta Phys. Sin. 62 036201 (in Chinese) [马文, 陆彦文 2013 物理学报 62 036201]

    [17]

    Kadau K, Germann T C, Lomdahl P S, Holian B L, Kadau D, Entel P, Kreth M, Westerhoff F, Wolf D E 2004 Metall. Mater. Trans. A 35 2719

    [18]

    Keblinski P, Wolf D, Phillpot S R, Gleiter H 1999 Scr. Mater. 41 631

    [19]

    Chen D 1995 Comput. Mater. Sci. 3 327

    [20]

    Hoover W G 1989 Phys. Rev. A 40 2814

    [21]

    Mishin Y, Mehl M J, Papaconstantopoulos D A, Voter A F, Kress J D 2001 Phys. Rev. B 63 224106

    [22]

    Li D, Wang F C, Yang Z Y, Zhao Y P 2014 Sci. China: Phys. Mech. Astron. 57 2177

    [23]

    Honeycutt J D, Andersen H C 1987 J. Phys. Chem. 91 4950

    [24]

    Yuan F P 2012 Sci. China: Phys. Mech. Astron. 55 1657

    [25]

    Kumar K S, Swygenhoven H V, Suresh S 2003 Acta Mater. 51 5743

    [26]

    Liao X Z, Srinivasan S G, Zhao Y H, Baskes M I, Zhu Y T 2004 Appl. Phys. Lett. 84 3564

    [27]

    Wang Y M, Ma E, Chen M W 2002 Appl. Phys. Lett. 80 2395

计量
  • 文章访问数:  2014
  • PDF下载量:  4247
  • 被引次数: 0
出版历程
  • 收稿日期:  2014-12-10
  • 修回日期:  2015-01-22
  • 刊出日期:  2015-06-05

纳米多晶铜的超塑性变形机理的分子动力学探讨

  • 1. 南京理工大学能源与动力工程学院, 南京 210094;
  • 2. 中国兵器工业集团第52研究所烟台分所, 烟台 264003
    基金项目: 

    江苏省普通高校研究生科研创新计划(批准号:KYLZ_0325)资助的课题.

摘要: 在聚能装药爆炸压缩形成射流的过程中, 伴随着金属药型罩的晶粒细化, 从原始晶粒30-80 μm细化到亚微米甚至纳米量级, 从微观层面研究其细化机理和动态超塑性变形机理具有很重要的科学意义. 采用分子动力学方法模拟了不同晶粒尺寸下纳米多晶铜的单轴拉伸变形行为, 得到了不同晶粒尺寸下的应力-应变曲线, 同时计算了各应力-应变曲线所对应的平均流变应力. 研究发现平均流变应力最大值出现在晶粒尺寸为14.85 nm时. 通过原子构型显示, 给出了典型的位错运动过程和晶界运动过程, 并分析了在不同晶粒尺寸下纳米多晶铜的塑性变形机理. 研究表明: 当晶粒尺寸大于14.85 nm时, 纳米多晶铜的变形机理以位错运动为主; 当晶粒尺寸小于14.85 nm时, 变形机理以晶界运动为主, 变形机理的改变是纳米多晶铜出现软化现象即反常Hall-Petch关系的根本原因. 通过计算结果分析, 建立了晶粒合并和晶界转动相结合的理想变形机理模型, 为研究射流大变形现象提供微观变形机理参考.

English Abstract

参考文献 (27)

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