Grain boundary migration of 〈110〉 tilt ∑11 and ∑21 boundaries in pure aluminum

Migrations of 〈110〉 tilt ∑11 and ∑27 boundaries in 99.99% purity aluminum have been investigated by Sun and Bauer technique as a function of temperature. In the JE11 tilt boundary, the activation energy for grain boundary migration is about 1/2 of the energy for Al-atom bulk-diffusion, indicating that the boundary motion may be governed by the grain boundary diffusion. While in the ∑27 tilt boundary, the activation energy for grain boundary migration is about 125kJ/mol, which agrees with the energy for Al-atom bulk-diffusion. Study of boundary structure observation by high resolution electron microscopy revealed that the grain boundary structure of ∑27 tilt boundary was consisted of edge dislocation array in which a space between dislocations was very short. It is considered that climb motion of the dislocations controlled to the motion of tilt boundaries consisted of edge dislocation array. From these results, it is concluded that the boundary motion of ∑27 tilt boundary may be governed by climb motion of their dislocations controlled by Al-atom bulk-diffusion.