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
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
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.