The effect of preliminary annealings at temperatures below the recrystallization temperature (T < 573 K) on the microstructure and activation energy of creep (Q_c) at T = 423 and 473 K of submicrocrystalline nickel obtained by severe plastic deformation (equal-channel angular pressing) was studied. The substantial change in the magnitude of Q_c in the samples after such "hyporecrystallization" annealings, in which only the specific grain-boundary state changes without changes in grain size, is explained as a consequence of various contributions of grain-boundary sliding to the total deformation upon creep.
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