Low Temperature Physics: 44, 976 (2018); https://doi.org/10.1063/1.5052688
Fizika Nizkikh Temperatur: Volume 44, Number 9 (September 2018), p. 1245-1253    ( to contents , go back )

Thermally activated deformation of nanocrystalline and coarse grained CoCrFeNiMn high entropy alloy in the temperature range 4.2–350 K

A.V. Podolskiy1, E. Schafler2, E.D. Tabachnikova1, M.A. Tikhonovsky3, and M.J. Zehetbauer2

1B. Verkin Institute for Low Temperature Physics and Engineering 47 Nauky Ave., Kharkiv 61103, Ukraine
E-mail: podolskiy@ilt.kharkov.ua

2Physics of Nanostructured Materials, Faculty of Physics, University of Vienna Boltzmanngasse 5, A-1090 Wien, Austria

3National Science Center, Kharkov Institute of Physics and Technology 1 Akademicheskaya Str., Kharkiv 61108, Ukraine

Received April 16, 2018, published online July 26, 2018

Abstract

Mechanical properties of a nanocrystalline (~ 60 nm) and a coarse grained (grain sizes ~ 4 μm) CoCrFeNiMn high entropy alloys were studied in uniaxial compression in the temperature range 4.2–350 K. Temperature dependences of yield strength, flow stress and strain rate sensitivity have been registered and analyzed in the framework of two thermal activation deformation models, that of thermal activation of local barrier overcoming, and that of Peierls valley double kink formation. Microscopic parameters of dislocation interaction with the barriers for thermally activated motion are estimated and low temperature deformation mechanisms are discussed.

Key words: high entropy alloy, nanocrystalline, low temperature, dislocation, thermal activation analysis.

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