Predicting single phase stability and segregation in the NbMoTaTi–(W,V) high entropy alloy system with the vacancy exchange potential

McAlpine, Samuel W.; Logan, Julie V.; Short, Michael P.

doi:10.1016/j.scriptamat.2020.08.043

Cited by 27 publications

(11 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These values are predicable using a combination of thermodynamic modelling (e.g., via DFT) and experimental methods. The tools available predict HEA thermal stability, melting point and a range of other properties (including thermal neutron cross section) have been used successfully, for example, References [ 28 , 31 , 179 ]. The methodology could be adapted and modified readily to capture other phenomena not presently considered.…”

Section: Challenges and Opportunities For Hea Developmentmentioning

confidence: 99%

High-Entropy Alloys for Advanced Nuclear Applications

Pickering

Carruthers

Barron

et al. 2021

Entropy

175

View full text Add to dashboard Cite

The expanded compositional freedom afforded by high-entropy alloys (HEAs) represents a unique opportunity for the design of alloys for advanced nuclear applications, in particular for applications where current engineering alloys fall short. This review assesses the work done to date in the field of HEAs for nuclear applications, provides critical insight into the conclusions drawn, and highlights possibilities and challenges for future study. It is found that our understanding of the irradiation responses of HEAs remains in its infancy, and much work is needed in order for our knowledge of any single HEA system to match our understanding of conventional alloys such as austenitic steels. A number of studies have suggested that HEAs possess ‘special’ irradiation damage resistance, although some of the proposed mechanisms, such as those based on sluggish diffusion and lattice distortion, remain somewhat unconvincing (certainly in terms of being universally applicable to all HEAs). Nevertheless, there may be some mechanisms and effects that are uniquely different in HEAs when compared to more conventional alloys, such as the effect that their poor thermal conductivities have on the displacement cascade. Furthermore, the opportunity to tune the compositions of HEAs over a large range to optimise particular irradiation responses could be very powerful, even if the design process remains challenging.

show abstract

Section: Challenges and Opportunities For Hea Developmentmentioning

confidence: 99%

High-Entropy Alloys for Advanced Nuclear Applications

Pickering

Carruthers

Barron

et al. 2021

Entropy

175

View full text Add to dashboard Cite

show abstract

“…Heat treatment prior to deformation, for example, homogenization heat treatment, is considered as an important way to improve deformability via microstructure control. Generally, micro-segregation would be present in the as-cast RHEAs due to different melting points of elements [96], resulting in poor deformability and inhomogeneous microstructure. Consequently, homogenization treatment at high temperature and long holding time with a certain cooling rate should be utilized to eliminate element segregation and to tailor the as-cast microstructure, especially phase structure.…”

Section: Microstructure Evolution By Heat Treatment Prior To Deformationmentioning

confidence: 99%

Research Progress of Refractory High Entropy Alloys: A Review

Xie

Liu

et al. 2022

Chin. J. Mech. Eng.

View full text Add to dashboard Cite

Owing to superior comprehensive performance than conventional superalloys at high temperature, refractory high entropy alloy (RHEA) is becoming a promising candidate for the next generation high-temperature material. Herein, contemporary aspects of corresponding development of RHEAs are reviewed to discuss various factors affecting the organization structure and service performance. It mainly covers alloying system and strengthening mechanism, the preparation method, plastic deformation and the related mechanism, as well as microstructure control by heat treatment. Firstly, the alloy systems and strengthening mechanism are introduced. This is followed by different preparation methods and the comparison of strengths and shortcomings based on different RHEAs. Then, hot deformation behavior and plastic deformation under different loadings are analyzed. Based on this, the influence of heat treatment on microstructures prior to and after the deformation is further summarized. Finally, some important research areas to be carried out in future are pointed out. This review will give a deep understanding of the effects of different factors on the service performance and provide scientific guide in designing RHEAs with improved performance.

show abstract

“…At high temperatures, vacancy properties are known to control RMEA performance such as the irradiation resistance, phase stability and creep deformation [ 26 , 27 , 28 , 29 ]. Thus, gaining a detailed understanding of vacancy energetics is a first important step to quantify the parameters that govern mass transport properties in these alloys.…”

Section: Introductionmentioning

confidence: 99%

Vacancy Energetics and Diffusivities in the Equiatomic Multielement Nb-Mo-Ta-W Alloy

Zhou

Marian

2022

Materials

View full text Add to dashboard Cite

In this work, we study vacancy energetics in the equiatomic Nb-Mo-Ta-W alloy, especially vacancy formation and migration energies, using molecular statics calculations based on a spectral neighbor analysis potential specifically developed for Nb-Mo-Ta-W. We consider vacancy properties in bulk environments as well as near edge dislocation cores, including the effect of short-range order (SRO) by preparing supercells through Metropolis Monte-Carlo relaxations and temperature on the calculation. The nudged elastic band (NEB) method is applied to study vacancy migration energies. Our results show that both vacancy formation energies and vacancy migration energies are statistically distributed with a wide spread, on the order of 1.0 eV in some cases, and display a noticeable dependence on SRO. We find that, in some cases, vacancies can form with very low energies at edge dislocation cores, from which we hypothesize the formation of stable `superjogs’ on edge dislocation lines. Moreover, the large spread in vacancy formation energies results in an asymmetric thermal sampling of the formation energy distribution towards lower values. This gives rise to effective vacancy formation energies that are noticeably lower than the distribution averages. We study the effect that this phenomenon has on the vacancy diffusivity in the alloy and discuss the implications of our findings on the structural features of Nb-Mo-Ta-W.

show abstract

Predicting single phase stability and segregation in the NbMoTaTi–(W,V) high entropy alloy system with the vacancy exchange potential

Cited by 27 publications

References 36 publications

High-Entropy Alloys for Advanced Nuclear Applications

High-Entropy Alloys for Advanced Nuclear Applications

Research Progress of Refractory High Entropy Alloys: A Review

Vacancy Energetics and Diffusivities in the Equiatomic Multielement Nb-Mo-Ta-W Alloy

Contact Info

Product

Resources

About