It was demonstrated that, in the case of palladium, face-centered cubic metals behaved in almost the same way. At high temperatures, a few representative high-energy high-angle (tilt or twist) boundaries exhibited the same relatively low self-diffusion activation energy and an isotropic liquid-like diffusion mechanism that was independent of the boundary misorientation. The simulations demonstrated that the decrease in activation energy at high temperatures was caused by a transition from a solid boundary structure at low temperatures to a liquid-like structure at high temperatures. Consistent with experiment, the transition temperature decreased with increasing grain boundary energy: i.e., with increasing degree of short-range structural disorder. The degree of long-range structural disorder in the zero-temperature grain boundary appeared to play no role in determining whether the grain boundary underwent such a transition at high temperatures.Self-Diffusion in High-Angle FCC Metal Grain Boundaries by Molecular Dynamics Simulation. Keblinski, P., Wolf, D., Phillpot, S.R., Gleiter, H.: Philosophical Magazine A, 1999, 79[11], 2735-61