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The mechanical properties under uniaxial compression of cylindrical samples of ultrafine-grain (UFG) zirconium (grain size ∼0.4μm) obtained by intense plastic strain (IPS)—a combination of extrusion, annealing, and drawing—have been studied in the temperature range 4.2–300K. The mechanical characteristics of UFG zirconium have been studied in two structural states and the results are compared with each other as well as with the characteristics of coarse-grain polycrystals of this material (state 1—samples after IPS, state 2—samples after IPS and annealing). It has been established that grain-size reduction under IPS substantially increases the yield stress of polycrystals (by a factor of 6 at 300K and by a factor of 4 at 77K) while maintaining a large reserve of plasticity up to 15%. Two stages of strain hardening and a decrease of the plastic-flow activation volume with increasing strain has been recorded in the strain diagrams of UFG zirconium. It is concluded that the main mechanisms determining the yield stress and strain hardening are the same for ultrafine- and coarse-grain zirconium: intragrain dislocation slip and twinning occur in parallel and interact with one another.

We report the first straightforward measurements of the diffusion coefficient of hydrogen migrating in icosahedral (i-) quasicrystal ribbons of Ti45Zr38Ni17 and in two-phase bulk samples containing both the i-phase and the Laves phase. It is found that at 273–353 K diffusion obeys Arrhenius’s law with activation energy 0.24 eV and that the ratio of the volumes of the phases changes at hydrogenization.