$\Sigma=5(210)$ 결정립계를 포함한 구리 bicrystal 모재상 스크래칭에 관한 분자역학모사

Molecular dynamics simulation of scratching a Cu bicrystal across a $\Sigma=5(210)$ grain boundary

  • 김기정 (고려대학교 신소재공학과) ;
  • 조민형 (고려대학교 신소재공학과) ;
  • 장호 (고려대학교 신소재공학과)
  • Kim Ki Jung (Dept. of Advanced Materials Eng., Korea Univ.) ;
  • Cho Min Hyung (Dept. of Advanced Materials Eng., Korea Univ.) ;
  • Jang Ho (Dept. of Advanced Materials Eng., Korea Univ.)
  • 발행 : 2004.11.01

초록

Molecular Dynamics(MD) method was used to investigate the change of friction force due to interaction between dislocations and a grain boundary when a Ni tip was scratched on a Cu bicrystal. The substrate comprised a Cu bicrystal containing a vertical$\Sigma=5(210)$ grain boundary. The moving tip for scratching simulation was consisted of fixed Ni atoms emulating a rigid tip. The indentation depth was $3.6\AA$ and the scratching was performed along <110>direction in the first grain. As the scratching was continued, nucleation and propagation of dislocations were observed. In the early stage, the grain boundary played as a barrier to moving dislocations and interrupting further dislocation movement with no dislocation resulting in no propagation across the grain boundary. As the Ni tip approached the grain boundary, dislocations were nucleated at the grain boundary and propagated to the second grain. However, stick-slip phenomena that were observed on a single crystal scratching were not observed in the bicrystal. And, instead, irregular oscillation of friction force was observed during the scratching due to the presence of a grain boundary.

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