Grain boundary energy and atomic structure of 〈110〉 symmetric tilt boundaries in copper

In order to clarify the correlation between the grain boundary energy and its atomic structure in copper, energy and atomic structure of 〈110〉 symmetric tilt boundaries in copper were simulated by molecular dynamics method. From the calculations, it was revealed that the grain boundary energy of 〈110〉 symmetric tilt boundaries strongly depended on misorientation and that there are deep energy cusps at the misorientation angles which correspond to (111) ∑3 and (113)∑11 symmetric tilt boundaries. It was found that the atomic structure of each 〈110〉 symmetric tilt boundary was described by three kinds of structural units which constitute (331) ∑19, (111) ∑3 and (113) ∑11 symmetric tilt boundaries respectively, and by (110) and (001) single crystal units. The volume expansion of each grain boundary was evaluated and compared with the grain boundary energy. As a result, it was elucidated that the grain boundary energy depends on the excess free volume of symmetric tilt boundaries.