Logo: to the web site of Uppsala University

uu.sePublications from Uppsala University
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Experimental and theoretical evidence of charge transfer in multi-component alloys: how chemical interactions reduce atomic size mismatch
Linköping Univ, Dept Phys Chem & Biol IFM, SE-58183 Linköping, Sweden..
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.ORCID iD: 0000-0001-5445-1374
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.ORCID iD: 0000-0001-6162-1167
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.ORCID iD: 0000-0002-5511-5986
Show others and affiliations
2021 (English)In: Materials Chemistry Frontiers, E-ISSN 2052-1537, Vol. 5, no 15, p. 5746-5759Article in journal (Refereed) Published
Abstract [en]

Ab initio simulations of a multi-component alloy using density functional theory (DFT) were combined with experiments on thin films of the same material using X-ray photoelectron spectroscopy (XPS) to study the connection between the electronic and atomic structures of multi-component alloys. The DFT simulations were performed on an equimolar HfNbTiVZr multi-component alloy. Structure and charge transfer were evaluated using relaxed, non-relaxed, as well as elemental reference structures. The use of a fixed sphere size model allowed quantification of charge transfer, and separation into different contributions. The charge transfer was generally found to follow electronegativity trends and results in a reduced size mismatch between the elements, and thus causes a considerable reduction of the lattice distortions compared to a traditional assumption based on tabulated atomic radii. A calculation of the average deviation from the average radius (i.e. the so-called δ-parameter) based on the atomic Voronoi volumes gave a reduction of δ from ca. 6% (using the volumes in elemental reference phases) to ca. 2% (using the volumes in the relaxed multi-component alloy phase). The reliability of the theoretical results was confirmed by XPS measurements of a Hf22Nb19Ti18V19Zr21 thin film deposited by sputter deposition. The experimentally observed core level binding energy shifts (CLS), as well as peak broadening due to a range of chemical surroundings, for each element showed good agreement with the calculated DFT values. The single solid solution phase of the sample was confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) including energy dispersive spectroscopy (EDS) with nm-resolution. These observations show that the HfNbTiVZr solid solution phase is non-ideal, and that chemical bonding plays an important part in the structure formation, and presumably also in the properties. Our conclusions should be transferable to other multi-component alloy systems, as well as some other multi-component material systems, and open up interesting possibilities for the design of material properties via the electronic structure and controlled charge transfer between selected metallic elements in the materials.

Place, publisher, year, edition, pages
Royal Society of Chemistry (RSC) Royal Society of Chemistry, 2021. Vol. 5, no 15, p. 5746-5759
National Category
Materials Chemistry Condensed Matter Physics
Identifiers
URN: urn:nbn:se:uu:diva-468314DOI: 10.1039/d1qm00380aISI: 000664149100001OAI: oai:DiVA.org:uu-468314DiVA, id: diva2:1640671
Funder
Swedish Research Council, 2018-04834Swedish Research Council, 2019-05403Swedish Research Council, 2018-05973Swedish Research Council, 2019-05487Knut and Alice Wallenberg Foundation, KAW-2018.0194Swedish Foundation for Strategic Research , FFL 15-0290Swedish National Infrastructure for Computing (SNIC)Available from: 2022-02-25 Created: 2022-02-25 Last updated: 2024-01-15Bibliographically approved
In thesis
1. Investigation of compositionally complex refractory metal based thin films
Open this publication in new window or tab >>Investigation of compositionally complex refractory metal based thin films
2024 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The search for new and improved materials has led to the discovery and establishment of compositionally complex or high-entropy materials. The work in this thesis is focused on the investigation of new compositionally complex materials based on the refractory metals of groups 4-6. The materials in this work were synthesised using non-reactive dc magnetron sputtering and three material systems have been studied: HfNbTiVZr-C, CrTiTaWNb-C and Nb-Mo-C. In the context of compositionally complex materials, this thesis aims to contribute specifically to questions regarding (i) the prediction of phase formation and stability (ii) the chemical interaction between atoms (iii) the correlation between the material properties and compositional complexity. 

The prediction of phase formation and stability using calculated phase diagram (CALPHAD) methods was studied in the HfNbTiVZr-C system. The findings suggest that CALPHAD methods are promising predictive tools, although kinetic effects during synthesis need to be taken into consideration. Furthermore, theoretical, and experimental evidence of charge transfer effects was demonstrated within the HfNbTiVZr-C system. The results of ab initio materials simulations and X-ray Photoelectron Spectroscopy (XPS) measurements highlight the importance of understanding and considering the local chemical environment and chemical interactions in compositionally complex materials.

The approach of metal alloying according to the valence electron concentration (VEC) to tune the mechanical properties was studied in the Nb-Mo-C system. The findings show the importance of microstructural effects on the mechanical properties in the studied thin film materials, which can overshadow the compositional or VEC variations. 

The response to Xe heavy-ion irradiation was studied in the CrTiTaWNb-C system using in situ irradiation experiments. This work presents a comparison between three different compositions: a TaW-rich alloy and carbide thin film as well as a near-equimolar carbide film. The findings indicate that both microstructure and chemical homogeneity play important roles when it comes to radiation damage tolerance in compositional complex materials.

This thesis demonstrates the elaborate and multifaceted nature of compositionally complex materials. Whether it comes to the fundamental understanding or the effective implementation of a materials design tool, many factors need to be taken into consideration, including chemical interactions between the constituent elements and microstructural effects.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2024. p. 70
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 2355
Keywords
Magnetron sputtering, Thin films, High entropy materials, Refractory metals, Transition metal carbides
National Category
Materials Chemistry
Research subject
Chemistry with specialization in Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-517268 (URN)978-91-513-2007-6 (ISBN)
Public defence
2024-03-01, Häggsalen - Ångströmlaboratory, Lägerhyddsvägen 1, Uppsala, 09:15 (English)
Opponent
Supervisors
Funder
Swedish Research Council, 2018-04834
Available from: 2024-02-07 Created: 2024-01-11 Last updated: 2024-02-07

Open Access in DiVA

fulltext(6907 kB)302 downloads
File information
File name FULLTEXT01.pdfFile size 6907 kBChecksum SHA-512
1c0ac5124eaf7fdb09ef1ef11b12aaf48e0b3d428cbbc3a9c6d73b52307fdbf7d51b1f30b18001a639ca71d9a931d6d84f14b8ea9d5fd72c23ad5a0e52e5ca6e
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Authority records

Osinger, BarbaraLindblad, RebeckaKarlsson, DennisFritze, Stefanvon Fieandt, KristinaJansson, UlfLewin, Erik

Search in DiVA

By author/editor
Osinger, BarbaraLindblad, RebeckaKarlsson, DennisFritze, Stefanvon Fieandt, KristinaJansson, UlfLewin, Erik
By organisation
Inorganic Chemistry
In the same journal
Materials Chemistry Frontiers
Materials ChemistryCondensed Matter Physics

Search outside of DiVA

GoogleGoogle Scholar
Total: 302 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 162 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf