Deformation Behavior and Mechanical Properties of High Entropy Alloys

A special issue of Metals (ISSN 2075-4701). This special issue belongs to the section "Entropic Alloys and Meta-Metals".

Deadline for manuscript submissions: closed (30 November 2023) | Viewed by 6127

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Guest Editor
The State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang, China
Interests: fatigue properties of metallic materials; fatigue cracking behavior of grain boundaries and twin boundaries; high-entropy alloys; grain boundary segregation; size effect of material deformation
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Special Issue Information

Dear Colleagues,

As a new type of metallic material, high-entropy alloys (HEAs) usually exhibit excellent mechanical properties, so they have received much attention in materials science and engineering. Furthermore, because there are more metastable states of HEAs than the traditional alloys during processing, corresponding mechanical properties can be obtained under different external conditions.

This Special Issue of Metals will focus on the microstructure, deformation behaviors, and mechanical properties of high-entropy alloys under different conditions, including but not limited to dislocation slip and twinning, grain boundary segregation, precipitation and phase transformation, low-temperature/high-temperature deformation, corrosion, wear, fatigue, etc.; and various methods for strengthening and toughening. The scope will cover fundamental research and all other aspects of alloy preparation, heat treatment, computer simulation, and engineering applications.

We are pleased to invite you to submit manuscripts to this Special Issue and share research results.

Prof. Dr. Linlin Li
Guest Editor

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Keywords

  • high-entropy alloys (HEAs)
  • processing
  • microstructure
  • deformation
  • mechanical properties

Published Papers (5 papers)

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Research

13 pages, 3696 KiB  
Article
Effect of Cu-Rich Phase Growth on Creep Deformation of Fe-Cr-Ni-Cu Medium-Entropy Alloy: A Phase Field Study
by Jianbing Gao, Lei Hu, Ninshu Ma, Xudong Fang, Zhenlin Xu and Yizhu He
Metals 2023, 13(7), 1219; https://doi.org/10.3390/met13071219 - 30 Jun 2023
Viewed by 874
Abstract
The Cu-rich phase is a high-efficiency and ultra-stable precipitation-strengthening phase and has been widely used in many steels and alloys, especially in heat-resistant steels and alloys. Creep damage is accompanied with the coarsening of the second phase. In the present work, the calculation [...] Read more.
The Cu-rich phase is a high-efficiency and ultra-stable precipitation-strengthening phase and has been widely used in many steels and alloys, especially in heat-resistant steels and alloys. Creep damage is accompanied with the coarsening of the second phase. In the present work, the calculation of phase diagrams (CALPHAD) method and elastic–plastic mechanics are coupled with the phase field (PF) approach to investigate the growth behavior and the accompanying stress/strain field evolution of nano-sized Cu-rich precipitates in an Fe-Cr-Ni-Cu medium-entropy alloy. The results show that creep strain is intensified with the coarsening of Cu-rich particles. The simulated size of Cu-rich particles is in good agreement previous experimental reports. The plastic strain tends to shear the Cu-rich phase when they are relatively fine (~<11 nm), and the size of the Cu-rich particles has a slight influence on the creep strain at this stage. In contrast, coarse Cu-rich precipitates (~>11 nm) are bypassed by the plastic strain due to the enhancing stress concentration around the interface, and the creep strain is rapidly aggravated with the growth of Cu-rich particles. The coarsening of Cu-rich particles will be retarded by the adjacent particles due to the overlapping of the diffusion zone, and hence the creep strain was reduced when crept for the same time. The retard effect will vanish when their distance is sufficiently long (~>60 nm). When the size of the Cu-rich particles is identical, the creep strain will be mitigated with elongation of the distance between two Cu-rich particles. Full article
(This article belongs to the Special Issue Deformation Behavior and Mechanical Properties of High Entropy Alloys)
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10 pages, 2284 KiB  
Communication
Eutectic MoNbTa(WC)x Composites with Excellent Elevated Temperature Strength
by Kejia Kang, Xiao Wang, Weibing Zhou, Peibo Li, Zihao Huang, Guoqiang Luo, Qiang Shen and Lianmeng Zhang
Metals 2023, 13(4), 687; https://doi.org/10.3390/met13040687 - 30 Mar 2023
Cited by 1 | Viewed by 1112
Abstract
To develop materials with a promising utilization future in the extreme environments of aerospace, the MoNbTa(WC)x composites were prepared by vacuum arc melting, of which the crystal structure, microstructure, and compression properties at elevated temperature were investigated. The MoNbTa(WC)x composites had [...] Read more.
To develop materials with a promising utilization future in the extreme environments of aerospace, the MoNbTa(WC)x composites were prepared by vacuum arc melting, of which the crystal structure, microstructure, and compression properties at elevated temperature were investigated. The MoNbTa(WC)x composites had eutectic structures that consisted of body-centered cubic (BCC) phase and eutectoid structures. The lamellar fine eutectoid structures were composed of BCC-structured high entropy alloy (HEA) Mo-Nb-Ta-W and FCC-structured carbide Mo-Nb-Ta-W-C. It was demonstrated that the ductility and elevated temperature strength was enhanced simultaneously combined with the effect of eutectic structures and WC addition. The optimal true yield strength and true fracture strain reached 1205 MPa and 29.2% in MoNbTa(WC)0.9 at 1200 °C, meanwhile, the fracture strain at ambient temperature was 13.96%. Distinct strain hardening was observed at the initial deformation stage of MoNbTa(WC)0.9 at 1200 °C. The compression performances of MoNbTa(WC)x were superior in comparison with most refractory high entropy alloys. Full article
(This article belongs to the Special Issue Deformation Behavior and Mechanical Properties of High Entropy Alloys)
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9 pages, 3626 KiB  
Communication
Microstructural Evolution of Shear Localization in High-Speed Cutting of CoCrFeMnNi High-Entropy Alloy
by Ming-Yao Su, Wei-Han Zhang, Yuan-Yuan Tan, Yan Chen, Hai-Ying Wang and Lan-Hong Dai
Metals 2023, 13(4), 647; https://doi.org/10.3390/met13040647 - 24 Mar 2023
Cited by 2 | Viewed by 1164
Abstract
Shear localization is one of the most important failure mechanisms subjected to high-strain-rate deformation and has significant effects on the process, plastic deformation, and catastrophic failure of a material. Shear localization was observed in serrated chips produced during the high-speed cutting of the [...] Read more.
Shear localization is one of the most important failure mechanisms subjected to high-strain-rate deformation and has significant effects on the process, plastic deformation, and catastrophic failure of a material. Shear localization was observed in serrated chips produced during the high-speed cutting of the CoCrFeMnNi high-entropy alloy. Electron backscatter diffraction was performed to systematically investigate microstructural evolution during shear banding. The elongation and subdivision of the narrow grains were observed in the areas adjacent to the shear band. The microstructure inside the shear band was found to be composed of equiaxed ultrafine grains. The results reveal that grain subdivision and dynamic recrystallization might have significant roles in the microstructural evolution of shear bands. These results offer key insights into our understanding of shear localization and high-speed machining behavior for high entropy alloys. Full article
(This article belongs to the Special Issue Deformation Behavior and Mechanical Properties of High Entropy Alloys)
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12 pages, 2571 KiB  
Article
Effect of the Synthesis Route on the Microstructure of HfxTi(1−x)NbVZr Refractory High-Entropy Alloys
by Maria Moussa, Stéphane Gorsse, Jacques Huot and Jean Louis Bobet
Metals 2023, 13(2), 343; https://doi.org/10.3390/met13020343 - 08 Feb 2023
Cited by 1 | Viewed by 1188
Abstract
In the present work, the effects of (i) Ti replacement by Hf and (ii) the synthesis method on microstructure and crystal structure evolution in the high-entropy alloy HfxTi(1−x)NbVZr are reported. The results of scanning electron microscopy and X-ray diffraction [...] Read more.
In the present work, the effects of (i) Ti replacement by Hf and (ii) the synthesis method on microstructure and crystal structure evolution in the high-entropy alloy HfxTi(1−x)NbVZr are reported. The results of scanning electron microscopy and X-ray diffraction analysis of alloys prepared by both arc-melting and induction-melting are compared with theoretical thermodynamic calculations using the CALPHAD approach. The non-equilibrium thermodynamic calculations agree well with the experimental observations for the arc-melted alloys: a mixture of body-centered cubic (BCC) and cubic C15 Laves phases occurs for low-Ti-concentration alloys and a single BCC phase is obtained for high-Ti alloys. The agreement is not as good when using the induction-melting method: equilibrium solidification calculations predict that the most stable state is a phase mixture of BCC, hexagonal close-packed, and a cubic C15 Laves phase, while experimentally only one BCC and one hexagonal C14 Laves phase were found. The estimation of the exact cooling rate and the lack of a thermodynamic database can explain the difference. In addition, for both methods, the thermodynamic calculation confirms that for a high Ti concentration, the BCC phase is stable, whereas phase separation is enhanced with a higher Hf concentration. Full article
(This article belongs to the Special Issue Deformation Behavior and Mechanical Properties of High Entropy Alloys)
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13 pages, 3191 KiB  
Article
Crystal Plasticity Model Analysis of the Effect of Short-Range Order on Strength-Plasticity of Medium Entropy Alloys
by Chen Li, Fuhua Cao, Yan Chen, Haiying Wang and Lanhong Dai
Metals 2022, 12(10), 1757; https://doi.org/10.3390/met12101757 - 19 Oct 2022
Cited by 2 | Viewed by 1382
Abstract
Numerous studies have demonstrated the widespread presence of chemical short-range order (SRO) in medium and high entropy alloys (M/HEAs). However, the mechanism of their influence on macroscopic mechanical behavior remains to be understood. In this paper, we propose a novel dislocation-based model of [...] Read more.
Numerous studies have demonstrated the widespread presence of chemical short-range order (SRO) in medium and high entropy alloys (M/HEAs). However, the mechanism of their influence on macroscopic mechanical behavior remains to be understood. In this paper, we propose a novel dislocation-based model of crystal plasticity, by considering both the dislocation blocking and coplanar slip induced by SRO. The effect of SRO on the plastic deformation of CoCrNi MEAs was investigated. We found that the yield strength increases monotonically with increasing SRO-induced slip resistance, but the elongation first appeared to increase and then decreased. Further analysis suggested that the plastic elongation is a result of the competition between grain rotation-induced deformation coordination and stress concentration, which depends on the slip resistance of the SRO. Full article
(This article belongs to the Special Issue Deformation Behavior and Mechanical Properties of High Entropy Alloys)
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