Atomistic simulations of energies for arbitrary grain boundaries. Part II: Statistical analysis of energies for tilt and twist grain boundaries

L Yang and CM Lai and SY Li, COMPUTATIONAL MATERIALS SCIENCE, 162, 268-276 (2019).

DOI: 10.1016/j.commatsci.2019.03.010

The orientation-dependency of grain boundary (GB) energy in Al is investigated using a cutoff sphere molecular dynamics model presented in Part I, which is applicable to arbitrary GBs. A GB energy dataset is generated using the model with deletion of over-close atoms and without rigid body translations in building the candidate configurations for a given GB. The dataset includes 12,062 tilt GBs (TIGBs) and twist GBs (TWGBs) with a broad range of misorientation angle/axis (theta/O) and GB-plane orientation (n). Statistical analyses of the results show that the energies overall increase with theta in the low-theta range and then level off for higher theta, and that the energies for non-coincident site lattice GBs also follow the increasing trend in the low-theta range. The energies of TIGBs decrease with the variation of O from the central regions to the edge and then corners of the stereographic triangle, and the O-dependency of GB energy becomes more severe for TWGBs. The current energy dataset suggests that the n-dependency of GB energy is best correlated with the orientation-dependency of surface energy following the broken-bond model and it does not support the existing perspective of low energies for GBs terminated by low-index or dense planes. For both types of GBs, the energy suffers a stronger influence from theta than n.

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