Superfunctional high-entropy alloys and ceramics by severe plastic deformation

Edalati, Parisa; Fuji, Masayoshi; Edalati, Kaveh

doi:10.1007/s12598-023-02340-x

Cited by 10 publications

(6 citation statements)

References 263 publications

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“…This study suggests a possible mechanism for the effect of shear strain on pressure-induced phase transformations through the formation of intermediate sheared phases. Such a mechanism can explain the acceleration of phase transformations by shear strain reported during HPT processing of various materials including metals such as cobalt, titanium, zirconium and their alloys [38][39][40][41][42], composites [44,45], semiconductors [46,47], ceramics [14][15][16][17][18], and high-entropy alloys and ceramics [48,49]. It was shown earlier that HPT processing not only refines the microstructure but also accelerates various allotropic phase transformations [11][12][13].…”

Section: Discussionmentioning

confidence: 91%

Mechanism of anatase-to-columbite TiO2 phase transformation via sheared phases: first-principles calculations and high-pressure torsion experiments

Hidalgo-Jiménez,

Akbay,

Ikeda

et al. 2023

J Mater Sci

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High-pressure torsion (HPT) can facilitate phase transformations in titanium dioxide (TiO2) and stabilize its high-pressure columbite phase, as an active photocatalyst, by shear straining under high pressure. This study aims to understand the mechanism underlying the acceleration of the anatase-to-columbite phase transformation by shear strain. A mechanism by considering sheared crystal structures as intermediate phases was proposed and examined using quantum mechanics in the framework of density functional theory (DFT) and HPT experiments. DFT energy and phonon calculations demonstrated the viability of the sheared structures as intermediate phases.Furthermore, the sheared structures were observed experimentally as new metastable phases using high-resolution transmission electron microscopy. These findings can explain the significant effect of shear strain on pressure-induced phase transitions, reported during severe plastic deformation of various metals and ceramics.

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Section: Discussionmentioning

confidence: 91%

Mechanism of anatase-to-columbite TiO2 phase transformation via sheared phases: first-principles calculations and high-pressure torsion experiments

Hidalgo-Jiménez,

Akbay,

Ikeda

et al. 2023

J Mater Sci

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“…13,14) Such materials are sometimes referred to as superfunctional materials due to their superior properties. 15,16) For the most recent progress in the field of SPD, the readers are referred to a 2023 special issue of Materials Transactions, 17) which covered various aspects like processing methods, [18][19][20][21][22][23][24][25][26] structural/microstructural features, [27][28][29][30][31][32][33] mechanical/functional properties, nanostructured metallic and non-metallic materials [56][57][58][59][60][61][62][63][64][65][66][67][68] and heterostructured materials. [69][70][71][72] Among various SPD methods, ECAP and ARB have the potential for commercialization.…”

Section: Introductionmentioning

confidence: 99%

Severe Plastic Deformation of Light Metals (Magnesium, Aluminum and Titanium) and Alloys by High-Pressure Torsion: Review of Fundamentals and Mechanical/Functional Properties

Edalati

2024

Mater. Trans.

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Light metals and alloys based on magnesium, aluminum, and titanium are of significance in daily life and industrial applications due to their low density and superior mechanical and functional properties. The formation of nanostructures and ultrafine grains can further improve the properties of these materials. High-pressure torsion (HPT), as a severe plastic deformation (SPD) method, is one of the most effective processes for nanostructuring these materials. Various modifications of HPT such as conventional HPT with discs, HPT with rings, and continuous HPT with strips and wires are currently applied to light metals and their alloys, composites, intermetallics, and metallic glasses. The HPT processing of these materials is effective for grain refinement, hardening through the Hall-Petch mechanism, lattice defect generation, phase transformations, and solid-state reactions through fast diffusion with reasonable time/thermal stability. This article after discussing these fundamental issues, reviews some mechanical and functional properties of nanostructured lightweight materials such as tensile, compression, and bending properties, superplasticity including room-temperature superplasticity, wear resistance, electrical conductivity, superconductivity, biocompatibility, hydrogen production, and hydrogen storage.

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“…High-entropy alloys are significantly better than conventional metals because of their high hardness, high toughness, and high thermal stability as well as their good wear resistance, corrosion resistance, and other factors [5]. Under some special conditions, highentropy alloys can even break the limits of existing materials, so they have become a hot spot within the development of material science [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Modeling of the Flow Field and Clad Geometry of a Molten Pool during Laser Cladding of CoCrCuFeNi High-Entropy Alloys

Tian,

Li,

et al. 2024

Materials

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A flow field analysis was performed in this research using the ANSYS Fluent module, and a dynamic heat source employing UDF was constructed using the DEFINE_PROFILE macro. A VOF model was developed to track the volume fraction of each fluid throughout the computational domain as well as the steady-state or transient condition of the liquid–gas interface in the free liquid surface area. To determine the distribution state and regularity of the molten pool flow field, the flow field velocity was calculated iteratively by linking the Simple algorithm with the horizontal set method. The molten pool was concave, indicating that the key hole was distributed narrowly. Inserting cross-sections at different depths yielded the vector distribution of the molten pool flow velocity along the depth direction. We set up monitoring sites along the molten pool’s depth direction and watched the flow change over time. We investigated the effects of the process parameters on the flow field’s vector distribution.

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Superfunctional high-entropy alloys and ceramics by severe plastic deformation

Cited by 10 publications

References 263 publications

Mechanism of anatase-to-columbite TiO2 phase transformation via sheared phases: first-principles calculations and high-pressure torsion experiments

Mechanism of anatase-to-columbite TiO2 phase transformation via sheared phases: first-principles calculations and high-pressure torsion experiments

Severe Plastic Deformation of Light Metals (Magnesium, Aluminum and Titanium) and Alloys by High-Pressure Torsion: Review of Fundamentals and Mechanical/Functional Properties

Modeling of the Flow Field and Clad Geometry of a Molten Pool during Laser Cladding of CoCrCuFeNi High-Entropy Alloys

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