Details
| Original language | English |
|---|---|
| Pages (from-to) | 137-150 |
| Number of pages | 14 |
| Journal | ACS Combinatorial Science |
| Volume | 20 |
| Issue number | 3 |
| Early online date | 22 Jan 2018 |
| Publication status | Published - 12 Mar 2018 |
Abstract
Ti-Ta thin films exhibit properties that are of interest for applications as microactuators and as biomedical implants. A Ti-Ta thin film materials library was deposited at T = 25 °C by magnetron sputtering employing the combinatorial approach, which led to a compositional range of Ti87Ta13 to Ti14Ta86. Subsequent high-throughput characterization methods permitted a quick and comprehensive study of the crystallographic, microstructural, and morphological properties, which strongly depend on the chemical composition. SEM investigation revealed a columnar morphology having pyramidal, sharp tips with coarser columns in the Ti-rich and finer columns in the Ta-rich region. By grazing incidence X-ray diffraction four phases were identified, from Ta-lean to Ta-rich: ω phase, α″ martensite, β phase, and a tetragonal Ta-rich phase (Ta(tetr)). The crystal structure and microstructure were analyzed by Rietveld refinement and clear trends could be determined as a function of Ta-content. The lattice correspondences between β as the parent phase and α″ and ω as derivative phases were expressed in matrix form. The β α″ phase transition shows a discontinuity at the composition where the martensitic transformation temperatures fall below room temperature (between 34 and 38 at. % Ta) rendering it first order and confirming its martensitic nature. A short study of the α″ martensite employing the Landau theory is included for a mathematical quantification of the spontaneous lattice strain at room temperature (max = 22.4(6) % for pure Ti). Martensitic properties of Ti-Ta are beneficial for the development of high-temperature actuators with actuation response at transformation temperatures higher than 100 °C.
Keywords
- combinatorial magnetron sputtering, GIXRD, heart valve metal, high-temperature shape memory alloy, high-throughput analysis, martensitic transformation, materials libraryα″ martensite, microactuators, SEM, tetragonal β-Ta, Ti-Ta, βphase, ω phase
ASJC Scopus subject areas
- Chemistry(all)
- General Chemistry
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In: ACS Combinatorial Science, Vol. 20, No. 3, 12.03.2018, p. 137-150.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Crystallographic Structure Analysis of a Ti-Ta Thin Film Materials Library Fabricated by Combinatorial Magnetron Sputtering
AU - Kadletz, Peter M.
AU - Motemani, Yahya
AU - Iannotta, Joy
AU - Salomon, Steffen
AU - Khare, Chinmay
AU - Grossmann, Lukas
AU - Maier, Hans Jürgen
AU - Ludwig, Alfred
AU - Schmahl, Wolfgang W.
N1 - © 2018 American Chemical Society
PY - 2018/3/12
Y1 - 2018/3/12
N2 - Ti-Ta thin films exhibit properties that are of interest for applications as microactuators and as biomedical implants. A Ti-Ta thin film materials library was deposited at T = 25 °C by magnetron sputtering employing the combinatorial approach, which led to a compositional range of Ti87Ta13 to Ti14Ta86. Subsequent high-throughput characterization methods permitted a quick and comprehensive study of the crystallographic, microstructural, and morphological properties, which strongly depend on the chemical composition. SEM investigation revealed a columnar morphology having pyramidal, sharp tips with coarser columns in the Ti-rich and finer columns in the Ta-rich region. By grazing incidence X-ray diffraction four phases were identified, from Ta-lean to Ta-rich: ω phase, α″ martensite, β phase, and a tetragonal Ta-rich phase (Ta(tetr)). The crystal structure and microstructure were analyzed by Rietveld refinement and clear trends could be determined as a function of Ta-content. The lattice correspondences between β as the parent phase and α″ and ω as derivative phases were expressed in matrix form. The β α″ phase transition shows a discontinuity at the composition where the martensitic transformation temperatures fall below room temperature (between 34 and 38 at. % Ta) rendering it first order and confirming its martensitic nature. A short study of the α″ martensite employing the Landau theory is included for a mathematical quantification of the spontaneous lattice strain at room temperature (max = 22.4(6) % for pure Ti). Martensitic properties of Ti-Ta are beneficial for the development of high-temperature actuators with actuation response at transformation temperatures higher than 100 °C.
AB - Ti-Ta thin films exhibit properties that are of interest for applications as microactuators and as biomedical implants. A Ti-Ta thin film materials library was deposited at T = 25 °C by magnetron sputtering employing the combinatorial approach, which led to a compositional range of Ti87Ta13 to Ti14Ta86. Subsequent high-throughput characterization methods permitted a quick and comprehensive study of the crystallographic, microstructural, and morphological properties, which strongly depend on the chemical composition. SEM investigation revealed a columnar morphology having pyramidal, sharp tips with coarser columns in the Ti-rich and finer columns in the Ta-rich region. By grazing incidence X-ray diffraction four phases were identified, from Ta-lean to Ta-rich: ω phase, α″ martensite, β phase, and a tetragonal Ta-rich phase (Ta(tetr)). The crystal structure and microstructure were analyzed by Rietveld refinement and clear trends could be determined as a function of Ta-content. The lattice correspondences between β as the parent phase and α″ and ω as derivative phases were expressed in matrix form. The β α″ phase transition shows a discontinuity at the composition where the martensitic transformation temperatures fall below room temperature (between 34 and 38 at. % Ta) rendering it first order and confirming its martensitic nature. A short study of the α″ martensite employing the Landau theory is included for a mathematical quantification of the spontaneous lattice strain at room temperature (max = 22.4(6) % for pure Ti). Martensitic properties of Ti-Ta are beneficial for the development of high-temperature actuators with actuation response at transformation temperatures higher than 100 °C.
KW - combinatorial magnetron sputtering
KW - GIXRD
KW - heart valve metal
KW - high-temperature shape memory alloy
KW - high-throughput analysis
KW - martensitic transformation
KW - materials libraryα″ martensite
KW - microactuators
KW - SEM
KW - tetragonal β-Ta
KW - Ti-Ta
KW - βphase, ω phase
UR - http://www.scopus.com/inward/record.url?scp=85043597658&partnerID=8YFLogxK
U2 - 10.1021/acscombsci.7b00135
DO - 10.1021/acscombsci.7b00135
M3 - Article
C2 - 29356502
AN - SCOPUS:85043597658
VL - 20
SP - 137
EP - 150
JO - ACS Combinatorial Science
JF - ACS Combinatorial Science
SN - 2156-8952
IS - 3
ER -