Internal friction of grain boundaries in two-dimensional Yukawa solids

Langevin dynamics simulations are performed to investigate the grain boundary internal friction (GBIF) in two-dimensional (2D) Yukawa solids under oscillating shear deformations. It is discovered that the GBIF exhibits a significant transition with the increasing misorientation angle, which can be used to distinguish the low- and high-angle grain boundaries (GBs). From the dependence of the GBIF on the shear amplitude and frequency, it is found that the internal friction of high-angle GBs exhibits typical properties of the linear anelasticity, while that of low-angle GBs does not. The variation trend of the calculated GB stiffness with the misorientation angle well agrees with that of GBIF, while the GB stiffnesses of the low- and high-angle GBs are both independent of frequency. For the transition between the low- and high-angle GBs of the misorientation angle $\ensuremath{\theta}=\ensuremath{\pi}/9$, the corresponding GB migration exhibits the normal diffusion, completely different from the ballistic motion of the GB migration of other misorientation angles.