Conclusions

  • Due to the periodic boundary conditions applied to the simulation box, vacancies in the lattice were created, and so the desired effect of segregation at the twist grain boundary was not observed. Instead, the Au atoms segregated to the vacancies. To counteract this problem the way in which the boundary conditions are imposed would have to be changed. One possibility would be to fix the boundary conditions to a perfect fcc lattice outside the box. However, this would require increasing the box size to avoid finite size effects. In turn this would result in a slower simulation which could be undesirable.
  • When comparing the results obtained from the EAM model and from L-J potentials it is apparent that the same segregation behavior was described by each. However, since this behavior occurred at lattice vacancies as opposed to a grain boundary, one may not conclude that the two models would also be in agreement for segregation at a grain boundary. Nevertheless, it does show that in some cases a simple approximation (like pair-potentials) to a many-body problem is sufficient to explain the behavior of physical systems.

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