The analysis of repeated transients in order to monitor the coupled evolution of dislocation velocity and mobile dislocation density in plastically deforming nanocrystalline Ni was reported. The stress relaxation series permitted the determination of the physical activation volume; indicating a rate-controlling mechanism which was different from that in coarse-grained Ni. The mobile dislocation exhaustion observed was correlated with the unusually high apparent work-hardening rate in the early stages of straining.

Activation Volume and Density of Mobile Dislocations in Plastically Deforming Nanocrystalline Ni. Y.M.Wang, A.V.Hamza, E.Ma: Applied Physics Letters, 2005, 86[24], 241917 (3pp)