TY - JOUR

T1 - Microstructure evolution and mechanical properties of a lamellar AlCoCrFeNi2.1 eutectic high-entropy alloy processed by high-pressure torsion

AU - Zhang, Zequn

AU - Fellner, Simon

AU - Hohenwarter, Anton

AU - Renk, Oliver

AU - Huang, Yong

AU - Chen, Zhuo

AU - Song, Kaikai

AU - Li, Caiju

AU - Gammer, Christoph

AU - Eckert, Jürgen

N1 - Publisher Copyright: © 2024 The Authors

PY - 2024/8/23

Y1 - 2024/8/23

N2 - High-pressure torsion (HPT) was applied to a lamellar eutectic high-entropy alloy (EHEA) to study the effect of severe plastic deformation (SPD) on the composite structure and mechanical properties. We found that the existence of multiple phases affects defect distribution and the fragmentation process during HPT. Structural evolution shows orientation dependence with respect to the shear plane, which finally leads to a refined multiphase structure with nanograins and vortex clusters after a shear strain γ of 24. In nanograins, dislocation-mediated deformation prevails. The high density of grain boundaries, forest dislocations, and the generation of deformation twins restrict dislocation movement. As a result, an EHEA with a yield strength of 1.75 GPa, an excellent tensile strength of 2.20 GPa, and an appreciable failure strain of 5 % is realized. Our results demonstrate that the HPT deformation process of the lamellar EHEA is significantly affected by the structure. SPD on the multiphase structure is a suitable route for designing high-strength yet ductile alloys.

AB - High-pressure torsion (HPT) was applied to a lamellar eutectic high-entropy alloy (EHEA) to study the effect of severe plastic deformation (SPD) on the composite structure and mechanical properties. We found that the existence of multiple phases affects defect distribution and the fragmentation process during HPT. Structural evolution shows orientation dependence with respect to the shear plane, which finally leads to a refined multiphase structure with nanograins and vortex clusters after a shear strain γ of 24. In nanograins, dislocation-mediated deformation prevails. The high density of grain boundaries, forest dislocations, and the generation of deformation twins restrict dislocation movement. As a result, an EHEA with a yield strength of 1.75 GPa, an excellent tensile strength of 2.20 GPa, and an appreciable failure strain of 5 % is realized. Our results demonstrate that the HPT deformation process of the lamellar EHEA is significantly affected by the structure. SPD on the multiphase structure is a suitable route for designing high-strength yet ductile alloys.

KW - Eutectic high-entropy alloys

KW - Grain refinement

KW - Mechanical properties

KW - Severe plastic deformation

KW - Structure evolution

UR - http://www.scopus.com/inward/record.url?scp=85201687306&partnerID=8YFLogxK

U2 - 10.1016/j.msea.2024.147139

DO - 10.1016/j.msea.2024.147139

M3 - Article

VL - 914.2024

JO - Materials science and engineering: A, Structural materials: properties, microstructure and processing

JF - Materials science and engineering: A, Structural materials: properties, microstructure and processing

SN - 0921-5093

IS - November

M1 - 147139

ER -