High entropy alloy nanocomposites produced by high pressure torsion

High-pressure torsion was applied to join two disks of single-phase equiatomic fcc CoCrFeMnNi and bcc HfNbTaTiZr high entropy alloys (HEAs). After 15 revolutions a bulk nanocomposite had developed with alternating nano-lamellae of elongated nanocrystalline CoCrFeMnNi and mixed amorphous-nanocrystalline HfNbTaTiZr, exhibiting complex microstructures with numerous vortex-like regions. While the fcc phase retains a rather homogeneous elemental distribution, the former bcc high entropy alloy experiences a chemical separation towards Ta-rich and Ta-poor phases. The joining of dissimilar HEAs under constrained conditions (cold shut) enables the design of novel HEA-based composites by non-equilibrium processing. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

High-pressure torsion is applied to join two disks of single-phase equiatomic fcc CoCrFeMnNi and bcc HfNbTaTiZr high entropy alloys, forming a bulk nanocomposite with alternating nano-lamellae of elongated nanocrystalline CoCrFeMnNi and mixed amorphous-nanocrystalline HfNbTaTiZr that exhibit complex microstructures. The joining process enables the design of novel HEA-based composites through non-equilibrium processing, resulting in chemical separation of the former bcc high entropy alloy and homogeneous elemental distribution in the fcc phase.