An investigation was made of the indices of grain boundaries in the pure metal. It was found that the coincidence site lattices (except  = 3) were either asymmetrical tilt boundaries with high indices, or had irrational boundary planes. In the case of  = 3, almost half were asymmetrical tilt boundaries which were displaced from the 111/111 symmetrical tilt boundary on the 110 zone. Such boundaries had low energies when compared with other boundaries of  = 3 type. The 211/211 incoherent twin was not observed, and this was explained on the grounds of its higher energy as compared with other boundaries on the 110 zone. The results were compared with those of previous studies where, unlike the present study, the boundaries had abutted the specimen surface during annealing.

V.Randle: Journal of Materials Science, 1995, 30[16], 3983-8