First-Principles Study of Physical Properties of (110) Symmetric Small-Angle Tilting Grain Boundary with Full Dislocation in Aluminum

The Peierls–Nabarro dislocation model is applied in this paper to investigate the [110] full dislocations on the (001), (111), and (1¯10) planes in pure Al, as well as the (110) small-angle tilting grain boundary (SATGB) composed of them. The findings demonstrate that the stress–strain fields of both dislocations and grain boundaries can be accurately described by a five-term single dislocation strain field. The Peierls stresses for the [110] edge-type dislocations on the (001), (111), and (1¯10) planes are 67.15 MPa, 114.93 MPa, and 847.56 MPa, respectively, exhibiting an increasing trend in magnitude. As the inter-dislocation distance decreases in the (110) SATGB of Al, the stress field, half-width, decomposition trend, and line energy of individual dislocations gradually decrease. The change in the line energy can be divided into three parts: Initially, there is a slow decrease when the distance is greater than ~200 Å. This is followed by a sharp drop in the line energy as the distance further decreases, with a slowing down of this trend at ~70 Å, where strain energy becomes dominant. In the final stage, the changes in the strained energy and core energy synergistically contribute. The (110) SATGB energy exhibits an increasing trend with the increment of the angle. The Peierls energy and force of the (110) SATGB composed of [110] full dislocations on the Al (001) and (111) surfaces exhibit minimal variation as the distance between dislocations changes, whereas a slight decrease is observed on the (110) surface. The present study provides valuable insights into the investigation of mechanical properties in Al alloys with nanometer-sized grains.