Observations of grain boundary structure in zinc

Abstract

We present calculations of dislocation spacing for grain boundaries in zinc and show that the spacings may be large enough to be resolved in transmission electron microscopy even at extreme deviations from ideal coincidence misorientations. This effect is a result of the need for the dislocation arrays to accommodate slight differences between the ideal and actual axial ratios in addition to the difference between the ideal and actual misorientations. The importance of the axial ratio accommodation in determining the dislocation structure is tested by observing grain boundaries at different temperatures, where the actual ratios differ. It is shown that the energy change of the dislocation arrays with varying temperature is sufficient to drive transformations of the interfacial structure.