计算物理 ›› 2010, Vol. 27 ›› Issue (6): 898-904.

• 研究论文 • 上一篇    下一篇

β-SiC单晶块体拉伸变形行为分子动力学研究

宗亮1,2, 许晓静1, 周海2   

  1. 1. 江苏大学先进成形技术研究所, 江苏 镇江 212013;
    2. 盐城工学院机械工程系, 江苏 盐城 224000
  • 收稿日期:2009-10-22 修回日期:2010-03-19 出版日期:2010-11-25 发布日期:2010-11-25
  • 作者简介:宗亮(1985-),男,硕士生,江苏扬州,主要从事计算机分子动力学方面的研究.
  • 基金资助:
    教育部留学回国人员科研启动基金(2006-331);江苏大学优秀学术青年骨干培养对象基金(1211110001)资助项目

Molecular Dynamics Simulation of Tension Deformation in Monocrystalline β-SiC Bulk

ZONG Liang1,2, XU Xiaojing1, ZHOU Hai2   

  1. 1. Institute of Advanced Forming Technology, Jiangsu University, Zhenjiang 212013, China;
    2. Department of Mechanical Engineer, Yancheng Institute of Technology, Yancheng 224000, China
  • Received:2009-10-22 Revised:2010-03-19 Online:2010-11-25 Published:2010-11-25

摘要: 用分子动力学方法研究面心立方SiC(β-SiC)、C元素置换掺杂β-SiC单晶块体体系[001]向拉伸变形行为,对体系的拉伸断裂微观机理和5×108/s,1×109/s,1×1010/s三种应变速率下的力学行为进行分析.发现当拉伸应变量达到某个临界值后,Si-C sp3,C-C sp3键会分别向Si-C sp2和C-C sp2弱键转化.形成一定量sp2键后,β-SiC内部出现孔洞并发生断裂.由于C-C sp3键比Si-C sp3键更易向sp2弱键转化,导致C元素掺杂会降低SiC的强度、弹性模量和拉伸断裂应变.此外还发现此三种应变速率不影响β-SiC的杨氏模量,但影响其拉伸强度.

关键词: SiC, 力学行为, 化学键, 分子动力学

Abstract: Tension simulations of[001]monocrystalline face-centered cubic SiC(β-SiC) and C-doped β-SiC bulks are performed with molecular dynamics method to investigate intrinsic deformation mechanisms and mechanical behaviors of β-SiC under strain rates of 5×108/s,1×109/s,1×1010/s.It is found that Si-C sp3 and C-C sp3 bonds respectively transform to Si-C sp2 and C-C sp2 bonds as soon as the strains reach certain critical values.As certain amounts of sp2 bonds are formed,instable fractures emerge in β-SiC.Since C-C sp2 bonds are formed earlier than Si-C sp2 bonds,the doping of C elements leads to the decrease of strength,Young's modulus and tension fracture strain of β-SiC.In addition,it is found that the strain rates have effects on tensile-strength,but not on Young's modulus.

Key words: SiC, mechanical behavior, chemical bonds, molecular dynamics

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