Creep Behavior of a Zirconium Alloy Processed by Equal-Channel Angular Pressing

V. Sklenickaa, J. Dvoraka, P. Krala, M. Svobodaa, M. Kvapilovaa, V.I. Kopylovb, S.A. Nikulinc and S.V. Dobatkinc, d aInstitute of Physics of Materials, Academy of Sciences of the Czech Republic, Zizkova 22, 616 62 Brno, Czech Republic bPhysico-Technical Institute of NAS Belarus, Kuprevicha 10, 220141 Minsk, Belarus cNational University of Science and Technology "MISIS", Leninskiy prospect 4, 119049 Moscow, Russia dA.A. Baikov Institute of Metallurgy and Materials Science of RAS, Leninskiy prospect 49, 119991 Moscow, Russia

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A Zr-2.5 wt%Nb alloy was processed by equal-channel angular pressing and then tested under creep conditions at 623 K using a tensile stress within the range from 120 to 300 MPa. The results show conventional power-law creep with a stress exponent of n > 3 which is consistent with an intragranular dislocation process involving the glide and climb of dislocations. It is demonstrated that diffusion creep is not important in these tests. For comparison purposes, the experiments were conducted using both the unprocessed alloy and after processing by equal-channel angular pressing. It was found that under same testing conditions the measured minimum creep rates in the pressed alloy with ultrafine grain sizes were faster than in the same alloy in a coarse-grained unprocessed condition.

DOI: 10.12693/APhysPolA.122.485 PACS numbers: 81.40.Lm, 62.20.Hg, 81.05.-t, 81.07.Bc, 81.70.Bt