The effect of grain boundary sliding on curvature-driven boundary migration in Zn bicrystals

Zinc bicrystals with an originally flat 89° symmetric tilt boundary tilted at 44° to the tensile direction were strained at high-temperature. Crystallographic slip in grains was suppressed by the special geometry of the bicrystals. Grain boundary sliding significantly increases the amount of capillarity-driven boundary migration which tends to turn the boundary normal to the free surfaces. The results are interpreted in terms of the reduced boundary mobility, which is sensitive to grain boundary sliding. The sliding can increase the reduced mobility by an order of magnitude.