MRS Proceedings

Articles

Nanometer Scale Mechanical Behavior of Grain Boundaries

2010 MRS Fall Meeting.

Chien-Kai Wanga1, Huck Beng Chewa1 and Kyung-Suk Kima1

a1 School of Engineering, Brown University, Providence, RI 02912, U.S.A.

ABSTRACT

A nonlinear field projection method has been developed to study nanometer scale mechanical properties of grain boundaries in nanocrystalline FCC metals. The nonlinear field projection is based on the principle of virtual work, for virtual variations of atomic positions in equilibrium through nonlocal interatomic interactions such as EAM potential interaction, to get field-projected subatomic-resolution traction distributions on various grain boundaries. The analyses show that the field projected traction produces periodic concentrated compression sites on the grain boundary, which act as crack trapping or dislocation nucleation sites. The field projection was also used to assess the nanometer scale failure processes of Cu Σ5 grain boundaries doped with Pb. It was revealed that the Pb dopants prevented the emission of dislocations by grain boundary slip and embrittles the grain boundary.

Key Words:

  • fracture;
  • grain boundaries;
  • embrittlement
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