SLIDING BEHAVIOR OF SYMMETRICAL TILT NEAR SIGMA=25(1(2)OVER-BAR-16) BOUNDARY IN ZINC BICRYSTALS

The sliding behaviour of a 67 degrees[10 (1) over bar 0] symmetric til t boundary close to a special boundary with Sigma = 25{1 (2) over tild e 16}, was investigated in zinc bicrystals. The bicrystals were creep tested at two values of tensile stress. Grain boundary sliding (GBS) a ccompanying migration in a fixed ratio occurred in both bicrystals. Th e value of the migration is approximate to 5 times that of the GBS its elf. For the bicrystal tested at a lower stress, the value of the unif orm distribution of GBS and migration along the boundary was observed. At the same time, when the bicrystal was tested at the higher stress level, the sliding and migration values gradually increased from one e nd of the boundary to the other one. The average ratio between GBS and boundary migration was practically independent of the stress value. T hese effects are interpreted in terms of the behaviour of DSC-dislocat ions generated by grain boundary dislocation sources, and produced as a result of the interaction between lattice dislocations and the grain boundary. (C) 1998 Elsevier Science S.A. All rights reserved.