Study of Energy Versus Misorientation for Grain Boundaries in Gold by Crystallite Rotation Method. I. (001) Twist Boundaries

摘要

Small gold crystallites (approx. 50 to 80 nm dia) were welded to thin film (001) single crystal gold substrates at a series of predetermined (001) twist angles in the range 0 to 45 degrees. A pure (001) twist boundary therefore existed in each welded neck region which could be observed directly by transmission electron microscopy at normal incidence. Upon annealing, the crystallites rotated around (001) when the boundary energy varied with theta. The crystallites rotated into three misorientations corresponding to the special sigma 1 and sigma 5 misorientations and a symmetry related misorientation at theta=45 degrees. These results indicate the existence of grain boundary dislocation (GBD) related cusps on the boundary energy versus theta curve at sigma 1 and sigma 5. The rotations occurred conservatively by the motion of screw GBDs which could be observed directly by the transmission microscopy in certain regimes of theta. The results are relevant to recent calculations of the energies of (001) twist boundaries and the applicability of the GBD/structural unit model for grain boundaries. (ERA citation 10:008798)