Structure models of massively transformed high niobium containing TiAl alloys

Christina Scheu; Limei Cha; Saso Sturm; Harald F. Chladil; Paul H. Mayrhofer; Helmut Clemens; Walter Wolf; Raimund Podloucky

Structure models of massively transformed high niobium containing TiAl alloys

Christina Scheu^*, Limei Cha, Saso Sturm, Harald F. Chladil, Paul H. Mayrhofer, Helmut Clemens, Walter Wolf, Raimund Podloucky

^*Corresponding author for this work

Research output: Contribution to journal › Conference article › peer-review

3 Scopus citations

Abstract

Ab-initio calculations using the Vienna ab-initio simulation package (VASP) were performed for a high Nb bearing γ-TiAl based alloy with a composition of Ti-47at.%Al-9at.%Nb in order to evaluate the effect of Nb on the crystal structure. The calculations revealed that the c/a ratio of the tetragonal γ-TiAl cell is reduced to ∼1, compared to the binary phase, if Nb atoms occupy Ti- and Al sites. In contrast, the c/a ratio is increased, in comparison to the pure γ-TiAl, if the Nb atoms occupy solely Ti sites and if Ti antisite defects (i.e. Ti atoms on the Al sublattice) are formed. The relaxed structure models were used to perform high-resolution transmission electron microscopy (HRTEM) and high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) image simulations. The results showed that the positions of the Nb atoms should be detectable by these high spatial resolution methods, although it might be easier by HAADF-STEM investigations due to the stronger dependence of the signal on the atomic number Z.

Original language	English
Pages (from-to)	401-406
Number of pages	6
Journal	Materials Research Society Symposium Proceedings
Volume	980
State	Published - 2007
Externally published	Yes
Event	2006 MRS Fall Meeting - Boston, MA, United States Duration: 27 Nov 2006 → 1 Dec 2006

Cite this

@article{63615e876200417bbcdf7b228b3f6517,

title = "Structure models of massively transformed high niobium containing TiAl alloys",

abstract = "Ab-initio calculations using the Vienna ab-initio simulation package (VASP) were performed for a high Nb bearing γ-TiAl based alloy with a composition of Ti-47at.%Al-9at.%Nb in order to evaluate the effect of Nb on the crystal structure. The calculations revealed that the c/a ratio of the tetragonal γ-TiAl cell is reduced to ∼1, compared to the binary phase, if Nb atoms occupy Ti- and Al sites. In contrast, the c/a ratio is increased, in comparison to the pure γ-TiAl, if the Nb atoms occupy solely Ti sites and if Ti antisite defects (i.e. Ti atoms on the Al sublattice) are formed. The relaxed structure models were used to perform high-resolution transmission electron microscopy (HRTEM) and high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) image simulations. The results showed that the positions of the Nb atoms should be detectable by these high spatial resolution methods, although it might be easier by HAADF-STEM investigations due to the stronger dependence of the signal on the atomic number Z.",

author = "Christina Scheu and Limei Cha and Saso Sturm and Chladil, {Harald F.} and Mayrhofer, {Paul H.} and Helmut Clemens and Walter Wolf and Raimund Podloucky",

year = "2007",

language = "英语",

volume = "980",

pages = "401--406",

journal = "Materials Research Society Symposium Proceedings",

issn = "0272-9172",

publisher = "Materials Research Society",

note = "2006 MRS Fall Meeting ; Conference date: 27-11-2006 Through 01-12-2006",

}

TY - JOUR

T1 - Structure models of massively transformed high niobium containing TiAl alloys

AU - Scheu, Christina

AU - Cha, Limei

AU - Sturm, Saso

AU - Chladil, Harald F.

AU - Mayrhofer, Paul H.

AU - Clemens, Helmut

AU - Wolf, Walter

AU - Podloucky, Raimund

PY - 2007

Y1 - 2007

N2 - Ab-initio calculations using the Vienna ab-initio simulation package (VASP) were performed for a high Nb bearing γ-TiAl based alloy with a composition of Ti-47at.%Al-9at.%Nb in order to evaluate the effect of Nb on the crystal structure. The calculations revealed that the c/a ratio of the tetragonal γ-TiAl cell is reduced to ∼1, compared to the binary phase, if Nb atoms occupy Ti- and Al sites. In contrast, the c/a ratio is increased, in comparison to the pure γ-TiAl, if the Nb atoms occupy solely Ti sites and if Ti antisite defects (i.e. Ti atoms on the Al sublattice) are formed. The relaxed structure models were used to perform high-resolution transmission electron microscopy (HRTEM) and high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) image simulations. The results showed that the positions of the Nb atoms should be detectable by these high spatial resolution methods, although it might be easier by HAADF-STEM investigations due to the stronger dependence of the signal on the atomic number Z.

AB - Ab-initio calculations using the Vienna ab-initio simulation package (VASP) were performed for a high Nb bearing γ-TiAl based alloy with a composition of Ti-47at.%Al-9at.%Nb in order to evaluate the effect of Nb on the crystal structure. The calculations revealed that the c/a ratio of the tetragonal γ-TiAl cell is reduced to ∼1, compared to the binary phase, if Nb atoms occupy Ti- and Al sites. In contrast, the c/a ratio is increased, in comparison to the pure γ-TiAl, if the Nb atoms occupy solely Ti sites and if Ti antisite defects (i.e. Ti atoms on the Al sublattice) are formed. The relaxed structure models were used to perform high-resolution transmission electron microscopy (HRTEM) and high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) image simulations. The results showed that the positions of the Nb atoms should be detectable by these high spatial resolution methods, although it might be easier by HAADF-STEM investigations due to the stronger dependence of the signal on the atomic number Z.

UR - http://www.scopus.com/inward/record.url?scp=34250875632&partnerID=8YFLogxK

M3 - 会议文章

AN - SCOPUS:34250875632

SN - 0272-9172

VL - 980

SP - 401

EP - 406

JO - Materials Research Society Symposium Proceedings

JF - Materials Research Society Symposium Proceedings

T2 - 2006 MRS Fall Meeting

Y2 - 27 November 2006 through 1 December 2006

ER -

Structure models of massively transformed high niobium containing TiAl alloys

Abstract

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