The mechanical shear behavior of Al single crystals and grain boundaries
X. Pang, N. Ahmed, R. Janisch, A. Hartmaier.
Journal of Applied Physics, 112, 023503, (2012)
To investigate the mechanical shear properties of interfaces in metals, we have determined the c-surfaces of different special tilt and twist grain boundaries in aluminum by means of ab initio calculations. From the c-surfaces, we obtained minimum energy paths and barriers, as well as the theoretical shear strength. For the  tilt grain boundaries, there is a pronounced easy-sliding direction along the tilt axis. The theoretical shear strength scales with the height of the slip barrier and exhibits a relation with the misorientation angle: the closer the angle to 90, the higher the shear stress. There is no simple relationship with the periodicity of the grain boundary, i.e., the R value or the grain boundary energy.
Keyword(s): ab initio calculations; aluminium; internal stresses; shear strength; slip; stacking faults; tilt boundaries; twist boundaries