High thermal stability of nanocrystalline FeNi2CoMo0.2V0.5 high-entropy alloy by twin boundary and sluggish diffusion

被引：0

作者：

Liang, N.N. ^{[1
]}

Xu, R.R. ^{[1
]}

Wu, G.Z. ^{[1
]}

Gao, X.Z. ^{[1
]}

Zhao, Y.H. ^{[1
]}

机构：

[1] Nano and Heterogeneous Materials Center, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing,210094, China

来源：

Materials Science and Engineering: A | 2022年 / 848卷

基金：

中国国家自然科学基金;

关键词：

Activation energy - Annealing - Backscattering - Cobalt alloys - Deformation - Diffusion - Entropy - Grain boundaries - Grain growth - High resolution transmission electron microscopy - High-entropy alloys - Iron alloys - Nanocrystalline alloys - Nanocrystals - Recrystallization (metallurgy) - Torsional stress;

D O I：

暂无

中图分类号：

学科分类号：

摘要：

A nanocrystalline (NC) face-centered cubic FeNi2CoMo0.2V0.5 high-entropy alloy was produced by high pressure torsion (HPT). The evolutions of microhardness and microstructure of the NC alloy during subsequent isochronal annealing were investigated systematically by electron back-scattering diffraction (EBSD) and high-resolution transmission electron microscopy (HRTEM). It was found that nano-grains and deformation nano-twin lamella were obtained at outer disk edge after HPT process with a hardness plateau of 450 HV. Isochronal annealing below 600 °C induced an evident hardening without precipitation effect, due to the annihilation of mobile dislocations and sustained deformation twin barriers. Evident recrystallization and grain growth of the NC FeNi2CoMo0.2V0.5 high-entropy alloy occurred during isochronal annealing at temperatures higher than 600 °C. The activation energies of recrystallization and grain growth of the NC FeNi2CoMo0.2V0.5 high-entropy alloy were calculated to be 350 kJ/mol and 272 kJ/mol, respectively, corresponding to a slow defects recovery process and a swift GB migration process. The high thermal stability of the NC FeNi2CoMo0.2V0.5 high-entropy was mainly caused by kinetic sluggish diffusion effect and deformation twin boundaries with thermodynamic low boundary energy, which retarded the movements of dislocations and grain boundary. © 2022 Elsevier B.V.

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