Physical metallurgy of concentrated solid solutions from low-entropy to high-entropy alloys

Cheng, Chien-Hong; Yang, Yi-Ju; Zhong, Yi-Zhen; Chen, Yang‐Yuan; Hsu, Tsun-Lai; Yeh, Jien‐Wei

doi:10.1016/j.cossms.2017.09.002

Cited by 72 publications

(21 citation statements)

References 42 publications

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“…In HEAs, high chemical inhomogeneity leads to lattice distortion, and therefore lattice potential energy variation and higher activation energy along the diffusion path, and consequentially lower diffusion efficiency than that in dilute alloys. In other words, an atom would experience a fluctuating lattice potential energy due to different lattice distortions from its neighbors as well as coordination bonding along its diffusion path and accordingly a higher activation energy to overcome deep traps [6,90,[95][96][97]. Sluggish atomic-level diffusion and transport [95][96][97] has been experimentally observed to reduce elemental segregation and defect clustering [12,18,21], and is also anticipated to hinder grain growth under irradiation.…”

Section: Thermally-induced Growth Of Nanocrystalline Nifecocrcu Thin mentioning

confidence: 99%

Thermal stability and irradiation response of nanocrystalline CoCrCuFeNi high-entropy alloy

et al. 2019

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Grain growth and phase stability of a nanocrystalline face-centered cubic (fcc) Ni0.2Fe0.2Co0.2Cr0.2Cu0.2 high-entropy alloy (HEA), either thermally-or irradiation-induced, are investigated through in-situ and post-irradiation transmission electron microscopy (TEM) characterization. Synchrotron and lab X-ray diffraction measurements are carried out to determine the microstructural evolution and phase stability with improved statistics. Under in-situ TEM observation, the fcc structure is stable at 300 C with a small amount of grain growth from 15.8 to ~ 20 nm being observed after 1800 s. At 500 C, however, some abnormal growth activities are observed after 1400 s, and secondary phases are formed. Under 3 MeV Ni room temperature ion irradiation up to an extreme dose of nearly 600 displacements per atom, the fcc phase is stable and the average grain size increases from 15.6 to 25.2 nm. Grain growth mechanisms driven by grain rotation, grain boundary curvature, and disorder are discussed.

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Section: Thermally-induced Growth Of Nanocrystalline Nifecocrcu Thin mentioning

confidence: 99%

Thermal stability and irradiation response of nanocrystalline CoCrCuFeNi high-entropy alloy

et al. 2019

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“…In 2006, he also established four core effects of HEAs [7]: High-entropy, severe-lattices-distortion, sluggish-diffusion, and the cocktail effect. With the new concepts, scientists are able to develop and expand alloys without restrictions [8][9][10][11][12]. Some HEAs have been found to have attractive properties on diffusion [13], oxidation [14], corrosion [15], fatigue [16], creep [17], fracture toughness [18], and elevated-temperature strength [19].…”

Section: Introductionmentioning

confidence: 99%

Effects of Mo, Nb, Ta, Ti, and Zr on Mechanical Properties of Equiatomic Hf-Mo-Nb-Ta-Ti-Zr Alloys

Tseng

Juan

Tso

et al. 2018

Entropy

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Nowadays refractory high-entropy alloys (RHEAs) are regarded as great candidates for the replacement of superalloys at high temperature. To design a RHEA, one must understand the pros and cons of every refractory element. However, the elemental effect on mechanical properties remains unclear. In this study, the subtraction method was applied on equiatomic HfMoNbTaTiZr alloys to discover the role of each element, and, thus, HfMoNbTaTiZr, HfNbTaTiZr, HfMoTaTiZr, HfMoNbTiZr, HfMoNbTaZr, and HfMoNbTaTi were fabricated and analyzed. The microstructure and mechanical properties of each alloy at the as-cast state were examined. The solid solution phase formation rule and the solution strengthening effect are also discussed. Finally, the mechanism of how Mo, Nb, Ta, Ti, and Zr affect the HfMoNbTaTiZr alloys was established after comparing the properties of these alloys.

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“…It was substantiated in [22,23] that during the formation of high-entropy alloys based on solid solutions with simple crystal lattices, several effects should be expected: High Entropy Effect, Lattice Distortion Effect, Cocktail Effect. The High Entropy Effect lies in the fact that the higher entropy of mixing (mainly configurational) in HEAs reduces the free energy of the phases of the solid solution and facilitates their formation, especially at higher temperatures.…”

Section: Literature Review and Problem Statementmentioning

confidence: 98%

Determination of regularities of the influence of the elemental composition of niobiumbased alloys on their structure and properties

Sоbоl

Мейлехов

Subbotinа

et al. 2020

EEJET

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Методом рентгенiвської дифрактометрiї дослiджено вплив складу двох, трьох, чотирьох i п'яти елементних сплавiв на основi нiобiю на їх фазово-структурний стан, середнiй розмiр кристалiтiв i коефiцiєнт теплового розширення в iнтервалi температур +20...-170 °С. В якостi елементiв наповнення використовувалися ванадiй, тантал, гафнiй, молiбден, цирконiй, вольфрам i титан. Цi елементи або в рiвноважному-при кiмнатнiй температурi (R T =+20 °С), або в високотемпературному станах мають ОЦК кристалiчну решiтку, подiбну Nb. Встановлено, що в сплавах на основi двох, трьох, чотирьох i п'яти елементiв для використаних в роботi складiв вiдбувається формування однофазного стану з ОЦК кристалiчною решiткою твердого розчину. На структурному рiвнi вплив складу сплаву позначається на спiввiдношеннi iнтенсивностей пiкiв дифракцiї вiд рiзних площин. Для двох порядкiв дифракцiї вiд найбiльш щiльноупакованної в ОЦК решiтцi площини {110} виявлено змiну величини iнтенсивностi для другого порядку дифракцiї. У найбiльшiй мiрi зменшення вiдносної iнтенсивностi вiдбувається в бiнарних сплавах з великою невiдповiднiстю за розмiрами атомних радiусiв складових компонент. У багатоелементних сплавах спостерiгається менше падiння iнтенсивностi. Це може бути пов'язано зi зменшенням дисторсiї кристалiчної решiтки внаслiдок упорядкування елементiв, якi складають сплав. На субструктурному рiвнi склад сплаву позначається на величинi середнього розмiру кристалiтiв. Для бiнарних складiв сплавiв найбiльший ефект пов'язаний з елементами наповнення Zr i Hf, якi мають значно бiльший атомний радiус. Це призводить до зменшення середнього розмiру кристалiтiв твердого розчину сплаву до найменшого значення 11 нм (сплав NbZr) i видiленню другої фази (сплав NbHf). Встановлено, що коефiцiєнт лiнiйного теплового розширення (КТР), визначений рентгендифракцiйним методом при 2-х температурах (RT=+20 °С i Т=-170 °С), в багатоелементних сплавах перевищує значення для вихiдних елементiв. Найбiльше збiльшення КТР спостерiгається в сплавах, що мiстять 17-26 ат. % V i W (якi мають найменший атомний радiус) Ключовi слова: багатоелементний сплав, нiобiй, високоентропiйний сплав, дисторсiя, фазовий склад, коефiцiєнт теплового розширення

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Physical metallurgy of concentrated solid solutions from low-entropy to high-entropy alloys

Cited by 72 publications

References 42 publications

Thermal stability and irradiation response of nanocrystalline CoCrCuFeNi high-entropy alloy

Thermal stability and irradiation response of nanocrystalline CoCrCuFeNi high-entropy alloy

Effects of Mo, Nb, Ta, Ti, and Zr on Mechanical Properties of Equiatomic Hf-Mo-Nb-Ta-Ti-Zr Alloys

Determination of regularities of the influence of the elemental composition of niobiumbased alloys on their structure and properties

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Physical metallurgy of concentrated solid solutions from low-entropy to high-entropy alloys

Cited by 72 publications

References 42 publications

Thermal stability and irradiation response of nanocrystalline CoCrCuFeNi high-entropy alloy

Thermal stability and irradiation response of nanocrystalline CoCrCuFeNi high-entropy alloy

Effects of Mo, Nb, Ta, Ti, and Zr on Mechanical Properties of Equiatomic Hf-Mo-Nb-Ta-Ti-Zr Alloys

Determination of regularities of the influence of the elemental composition of niobium­based alloys on their structure and properties

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Determination of regularities of the influence of the elemental composition of niobiumbased alloys on their structure and properties