Simulations were used to clarify the effects of grain growth upon grain-boundary diffusion creep and grain-boundary sliding during high-temperature deformation of a nanocrystalline Pd model microstructure. The initial microstructure consisted of a 25-grain polycrystal with an average grain size of about 15nm and a columnar grain shape. Prior to the onset of significant grain growth, the deformation proceeded via the of Coble creep mechanism, accompanied by grain-boundary sliding. While grain growth was generally known to decrease the creep rate due to the increase in the average grain size, the results obtained revealed an enhanced creep rate at the onset of grain growth, when rapid grain-boundary migration occurred. The enhanced creep rate was shown to arise from topological changes during the initial growth phases, which enhanced both the stress-induced grain-boundary diffusive fluxes and grain-boundary sliding. Dislocations generated as a result of grain-rotation-induced grain coalescence and grain-boundary decomposition in the vicinity of certain triple junctions also contributed to the deformation.Effects of Grain Growth on Grain-Boundary Diffusion Creep by Molecular-Dynamics Simulation. Haslam, A.J., Yamakov, V., Moldovan, D., Wolf, D., Phillpot, S.R., Gleiter, H.: Acta Materialia, 2004, 52[7], 1971-87