高等学校化学学报 ›› 2009, Vol. 30 ›› Issue (11(1)): 73.

• 研究论文 • 上一篇    下一篇

硅纳米线Bauschinger效应的原子模拟

孟庆元, 荆宇航   

  1. 哈尔滨工业大学航天科学与力学系, 哈尔滨 150001
  • 收稿日期:2009-07-28 出版日期:2009-11-30 发布日期:2009-11-30
  • 通讯作者: 荆宇航, 男, 从事纳米力学方面研究. E-mail: jingyuhang@gmail.com
  • 基金资助:

    国家自然科学基金(批准号: 10772062)资助.

Atomistic Simulations of Bauschinger Effect on Silicon Nanowire

MENG Qing-Yuan, JING Yu-Hang*   

  1. Department of Astronautical Science and Mechanics, Harbin Institute of Technology, Harbin 150001
  • Received:2009-07-28 Online:2009-11-30 Published:2009-11-30
  • Contact: JING Yu-Hang. E-mail: jingyuhang@gmail.com
  • Supported by:

    国家自然科学基金(批准号: 10772062)资助.

摘要:

采用分子动力学方法, 使用Stillinger-Weber势函数研究了单晶硅纳米线的Bauschinger效应. 在轴向载荷作用下的研究结果表明, 轴向拉伸和压缩载荷在力学性能上具有不对称性, 由于自由表面的影响, 轴向拉伸试验得到的杨氏模量和屈服应力要大于轴向压缩试验的结果. 同时研究发现, 在轴向拉伸载荷作用下纳米线的塑性变形表现为原子先沿{111}面滑移, 之后在瓶颈处发生重构. 考虑Bauschinger效应, 轴向压缩和拉伸载荷先后被施加到硅纳米线上, 结果发现反向屈服应力降低, 同时随着预应变的增加Bauschinger效应增强.

关键词: 硅纳米线; 分子动力学; Bauschinger效应

Abstract:

Molecular dynamics simulations with Stillinger-Weber potential were used to study the Bauschinger effect on a single-crystalline silicon nanowire. In the case of uniaxial loading, the simulation results show that the uniaxial tensile and compressive loading exhibit asymmetry in mechanical property. Compared with those of compressive test, the higher Young's modulus and yield stress are obtained in the tension loading, which can be introduced by the free surface effect. Additionally, the plastic deformation due to tension loading is characterized by {111} slippages and rearrangements of atoms close to the necking region. In consideration of the Bauschinger effect, the compression-followed-by-tension process is applied to the silicon nanowire. It has been found that the reversal yield stress decreases and the Bauschinger effect increases with the increasing of the prestrain.

Key words: Si nanowire; Molecular dynamics; Bauschinger effect

TrendMD: