liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • 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
Al-based Thin Film Quasicrystals and Approximants
Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

In this work, Al-based quasicrystalline and approximant phases have been synthesized in thin films using magnetron sputter deposition. Quasicrystals are structures having long-range order and rotational symmetries which are inconsistent with periodicity. Due to their unusual structure, quasicrystals show many anomalous and unique physical properties, including; high hardness, wear resistance, low friction, and low electrical and thermal conductivities. Approximants are a family of periodic phases that are related to the quasicrystals. These phases share the local atomic arrangement of quasicrystals and have as a result many similar physical properties. Bulk quasicrystals are too brittle for many of the suggested applications, and instead the most important area of applications concerns that of surface  coatings.

Multilayered Al/Cu/Fe thin films, with a nominal global composition   corresponding to the quasicrystalline phase, have been deposited onto Si and Al2O3 substrates. During isothermal annealing at temperatures up to 700 °C homogeneous thin films were formed. When Si was used as substrate a film-substrate reaction occured already below 390 °C, where Si diffused into the film. This changed the composition, and promoted the formation of the cubic α-approximant phase. Annealing at 600 °C for 4 h the cubic α-approximant phase formed in a polycrystalline state, with a small amount of a second phase, τ7-Al3Fe2Si3. The film was within 1.5 at.% of the ideal composition of the α-approximant phase and contained 8 at.% Si. Continued annealing for 64 h provided for more diffusion of Si to 12 at.%. No degradation of the crystal quality of the remaining α-phase was observed even after as much as 150 h of treatment.

Nanomechanical and nanotribological properties, including hardness, elastic modulus, friction and toughness, were investigated for the approximant and quasicrystalline samples. The approximant phase, annealed at 600 °C for 4 h, proved to be harder and had higher elastic modulus values than the quasicrystalline phase, about, 15.6 GPa and 258 GPa, respectively. The fracture toughness of the approximant, on the other hand, <0.1 MPa/m½, was inferior to that of the quasicrystals with 1.5 MPa/m½. Low friction coefficients of about 0.13 were measured for both phases.

When annealing multilayered Al/Cu/Co thin films on Al2O3 the decagonal quasicrystal d-Al-Cu-Co was formed at 500 °C. The XRD peak intensities were rather low, but after raising the temperature to 850 °C a large increase in intensity and a complete texturing with the 10-fold periodic axis aligned with the substrate normal occurred. When annealing the same samples on Si, the decagonal quasicrystal was again found, however, TEM and EDX measurements identified 3-6 at.% Si inside the quasicrystalline grains. Also the decagonal d-Al-Cu-Co-Si quasicrystal was textured with the 10-fold periodic axis aligned with the surface normal. The texture was however not complete as in the thin films grown on Al2O3. Raising the temperature to over 700 °C led to the formation of other crystalline phases in favor of the decagonal d-Al-Cu-Co-Si.

For the Cu-Al-Sc system quasicrystalline thin films were grown directly from the vapor phase by utilizing ion-assistance during growth at low temperatures, thus eliminating the need for post-annealing. Diffraction experiments revealed that amorphous films were formed at room temperature. The quasicrystalline phase formed at a substrate temperature of 340 °C with an improved quality at higher temperatures up to 460 °C. The quasicrystal film quality was improved by increasing the ion-flux during with ion energies of 26.7 eV. Increasing the ion energy further was however found to cause resputtering and defects in the films. Electron microscopy revealed a polycrystalline microstructure with crystal grains in the shape of thin needles.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2013. , 61 p.
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1538
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:liu:diva-96910ISBN: 978-91-7519-537-7 (print)OAI: oai:DiVA.org:liu-96910DiVA: diva2:643930
Public defence
2013-09-27, Planck, Fysikhuset, Campus Valla, Linköpings universitet, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2013-08-29 Created: 2013-08-29 Last updated: 2016-08-31Bibliographically approved
List of papers
1. Formation of α-approximant and quasicrystalline Al-Cu-Fe thin films
Open this publication in new window or tab >>Formation of α-approximant and quasicrystalline Al-Cu-Fe thin films
2012 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 526, 74-80 p.Article in journal (Refereed) Published
Abstract [en]

Multilayered Al/Cu/Fe thin films have been deposited by magnetron sputtering onto Si and Al2O3 substrates with a nominal global composition corresponding to the quasicrystalline phase, 5:2:1. Subsequent annealing was performed on the samples up to 710 degrees C. It is found that when using Si as a substrate a film-substrate reaction occurs already below 390 degrees C, where Si diffuses into the film. This changes the composition, promoting the formation of the alpha-approximant Al55Si7Cu25.5Fe12.5 in the temperature range 400 to 650 degrees C over the quasicrystalline psi-phase. When annealing the same Al-Cu-Fe thin film grown on Al2O3 substrates the Al62.5Cu25Fe12.5 icosahedral quasicrystalline phase is formed.

Place, publisher, year, edition, pages
Elsevier, 2012
Keyword
Quasicrystal, Approximant, Al-Cu-Fe-Si, X-ray diffraction, Annealing, Phase evolution, Multilayer, Sputtering
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-89532 (URN)10.1016/j.tsf.2012.11.009 (DOI)000313703200012 ()
Note

Funding Agencies|Swedish Foundation for Strategic Research (SSF) Strategic Research Center in Materials Science for Nanoscale Surface Engineering (MS2E)||

Available from: 2013-02-26 Created: 2013-02-26 Last updated: 2017-12-06
2. Structure and Composition of Al(Si)CuFe Approximant Thin Films Formed by Si Substrate Diffusion
Open this publication in new window or tab >>Structure and Composition of Al(Si)CuFe Approximant Thin Films Formed by Si Substrate Diffusion
Show others...
2014 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 550, no 1, 105-109 p.Article in journal (Refereed) Published
Abstract [en]

Multilayered Al/Cu/Fe thin films with composition close to the quasicrystalline phase have been prepared by magnetron sputtering. Annealing at 600 °C yields a homogeneous film of the cubic a-approximant phase by Si substrate diffusion, which prevents the formation of the quasicrystalline phase. After 4 h annealing the film contained 8 at.% Si, which corresponds to the expected value of the a-approximant. The amount of Si in the films was found to slowly increase to ~12 at.% during continued annealing (64 h) while the α-approximant phase was retained. The lattice parameter was found to  continuously decrease as Al became substituted with Si. The film is observed to be polycrystalline with individual grains being strained in varying magnitude, and with no preferential orientation relationship to the substrate or each other.

Place, publisher, year, edition, pages
Elsevier, 2014
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-96906 (URN)10.1016/j.tsf.2013.10.121 (DOI)000328499700017 ()
Available from: 2013-08-29 Created: 2013-08-29 Last updated: 2017-12-06Bibliographically approved
3. Mechanical and Tribological Properties of AlCuFe Quasicrystal and Al(Si)CuFe Approximant Thin Films
Open this publication in new window or tab >>Mechanical and Tribological Properties of AlCuFe Quasicrystal and Al(Si)CuFe Approximant Thin Films
Show others...
2016 (English)In: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 31, no 2, 232-240 p.Article in journal (Refereed) Published
Abstract [en]

Multilayered thin films of Al/Cu/Fe have been prepared by magnetron sputtering and annealed into the quasicrystalline or approximant phases, for Al2O3 or Si substrates, respectively. The nanomechanical and nanotribological properties; hardness, elastic modulus, friction and toughness, have been measured using a triboindenter and analytical methods. The approximant phase, annealed at 600 °C for 4 h, proved to be harder and had higher elastic modulus values than the quasicrystalline phase, about, 15.6 GPa and 258 GPa, respectively. The fracture toughness of the approximant, <0.1 MPa/m½, was however inferior to that of the quasicrystals with 1.5 MPa/m½. The friction coefficients were measured in a range of 0.10-0.14 for the quasicrystalline and approximant thin films.

Place, publisher, year, edition, pages
Cambridge University Press, 2016
Keyword
quasicrystal, approximant, thin film, hardness, elastic modulus, friction, toughness, tribology, TEM, STEM, XRD
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-96907 (URN)10.1557/jmr.2015.384 (DOI)000371704900007 ()
Note

Funding agencies:  Knut and Alice Wallenberg Foundation; Swedish Government Strategic Research Area Grant in Materials Science (SFO Mat-LiU) on Advanced Functional Materials

Available from: 2013-08-29 Created: 2013-08-29 Last updated: 2017-12-06Bibliographically approved
4. Phase Evolution of Multilayered Al/Cu/Co Thin Films into Decagonal Al-Cu-Co and Al-Cu-Co-Si Quasicrystalline Phases
Open this publication in new window or tab >>Phase Evolution of Multilayered Al/Cu/Co Thin Films into Decagonal Al-Cu-Co and Al-Cu-Co-Si Quasicrystalline Phases
Show others...
2013 (English)Manuscript (preprint) (Other academic)
Abstract [en]

Multilayered Al/Cu/Co thin films have been prepared by magnetron sputtering on Al2O3(0001) and Si(001) substrates and the phase evolution has been investigated. The decagonal d-Al-Cu-Co and d-Al-Cu-Co-Si phases were found to form at 500 °C, and at 600 °C these were the only phases. At increasing temperatures, the quasicrystals grew larger in size, up to 500 nm, although always smaller for the d-Al-Cu-Co-Si, and obtained a texturing with the 10-fold periodic axis aligned with the substrate normal. The d-Al-Cu-Co phase persisted to more than 850 °C, with a complete texturing, while the d-Al-Cu-Co-Si phase was replaced by other crystalline phases at 800 °C.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-96908 (URN)
Available from: 2013-08-29 Created: 2013-08-29 Last updated: 2016-08-31Bibliographically approved
5. Ion-assisted Growth of Quasicrystalline Cu-Al-Sc Directly from the Vapor Phase
Open this publication in new window or tab >>Ion-assisted Growth of Quasicrystalline Cu-Al-Sc Directly from the Vapor Phase
Show others...
2013 (English)Manuscript (preprint) (Other academic)
Abstract [en]

Ion assisted depositions have been used to grow the Al38Cu46Sc16 quasicrystalline phase directly from the vapor phase in thin film form. Diffraction experiments reveal that amorphous films are formed at room temperature. The quasicrystalline phase formed at a substrate temperature of 340 °C with an improved quality at higher temperatures up to 460 °C. The quasicrystal film quality is improved by increasing the ion flux during ion-assisted growth with ion energies of 26.7 eV. Increasing the ion energy further was however found to cause resputtering and defects in the film. Electron microscopy reveals a polycrystalline microstructure with crystal grains in the shape of thin needles.

Keyword
Quasicrystal, thin film, ion-assisted depositions, magnetron sputtering, TEM, XRD
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-96909 (URN)
Available from: 2013-08-29 Created: 2013-08-29 Last updated: 2016-08-31Bibliographically approved

Open Access in DiVA

Al-based Thin Film Quasicrystals and Approximants(3426 kB)1401 downloads
File information
File name FULLTEXT01.pdfFile size 3426 kBChecksum SHA-512
3ea014b67a3ad5bd460e6911bc825b1a30f61cf855870f82b015129658eac680415b02c901e87559d2230fc768deed1b17d97939df96b1b6f4e400bd6f8c4237
Type fulltextMimetype application/pdf
omslag(3081 kB)29 downloads
File information
File name COVER01.pdfFile size 3081 kBChecksum SHA-512
a3108bf143f28c5fac06a137c335e60a770005f25e63f73ae826405060b71793d6ff2dcfee07f66ac849a7bd8215f0a1ad76b8c3ff34107d4dd4e141ec81c27e
Type coverMimetype application/pdf

Authority records BETA

Olsson, Simon

Search in DiVA

By author/editor
Olsson, Simon
By organisation
Thin Film PhysicsThe Institute of Technology
Natural Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 1401 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

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 788 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • 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