Evolution of Microstructure and Mechanical Properties of a CoCrFeMnNi High-Entropy Alloy during High-Pressure Torsion at Room and Cryogenic Temperatures
Sergey Zherebtsov 1, Nikita Stepanov 1
, Yulia Ivanisenko 2, Dmitry Shaysultanov 1, Nikita Yurchenko 1, Margarita Klimova 1,* and Gennady Salishchev 1
, Yulia Ivanisenko 2, Dmitry Shaysultanov 1, Nikita Yurchenko 1, Margarita Klimova 1,* and Gennady Salishchev 1
1
Laboratory of Bulk Nanostructured Materials, Belgorod State University, 308015 Belgorod, Russia
2
Karlsruhe Institute of Technology, Institute of Nanotechnology, 76021 Karlsruhe, Germany
*
Author to whom correspondence should be addressed.
Metals 2018, 8(2), 123; https://doi.org/10.3390/met8020123
Received: 16 January 2018 / Revised: 6 February 2018 / Accepted: 7 February 2018 / Published: 10 February 2018
(This article belongs to the Special Issue Microstructure and Mechanical Properties of Structural Metals and Alloys)
Abstract
High-pressure torsion (HPT) is applied to a face-centered cubic CoCrFeMnNi high-entropy alloy at 293 and 77 K. Processing by HPT at 293 K produced a nanostructure consisted of (sub)grains of ~50 nm after a rotation for 180°. The microstructure evolution is associated with intensive deformation-induced twinning, and substructure development resulted in a gradual microstructure refinement. Deformation at 77 K produces non-uniform structure composed of twinned and fragmented areas with higher dislocation density then after deformation at room temperature. The yield strength of the alloy increases with the angle of rotation at HPT at room temperature at the cost of reduced ductility. Cryogenic deformation results in higher strength in comparison with the room temperature HPT. The contribution of Hall–Petch hardening and substructure hardening in the strength of the alloy in different conditions is discussed. View Full-TextKeywords:
high-entropy alloys; high-pressure torsion; microstructure evolution; twinning; mechanical properties
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Zherebtsov, S.; Stepanov, N.; Ivanisenko, Y.; Shaysultanov, D.; Yurchenko, N.; Klimova, M.; Salishchev, G. Evolution of Microstructure and Mechanical Properties of a CoCrFeMnNi High-Entropy Alloy during High-Pressure Torsion at Room and Cryogenic Temperatures. Metals 2018, 8, 123.
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