Crystal structure of tau(5)-TiNi(2-x)Al(5) (x=0.48) and isotypic {Zr,Hf}Ni(2-x)Al(5-y)
- Author(s)
- Josef Bursik, Andrij Grytsiv, Vladimir Pomjakushin, Herta Silvia Effenberger, Peter Franz Rogl
- Abstract
The crystal structure of the compd. in the Al-rich region of the Ti-Ni-Al system, .tau.5-TiNi2-xAl5, x = 0.48, has been derived from X-ray powder and single crystal, neutron powder and electron diffraction (space group I4/mmm, a = 0.3984(2) nm, c = 1.4073(3) nm, RF2 = 0.0133). Titanium atoms were unambiguously located from neutron powder data. .tau.5 is isotypic with the crystal structure of ZrNi2Al5. Detailed transmission electron microscopy (TEM) in several crystallog. directions confirmed the lattice parameters and crystal symmetry. Although occupancy of Ni in the 4e site revealed a defect (occ. = 0.76), no significant homogeneity region was obsd. for this phase at 1020C. Rietveld analyses of X-ray powder diffraction data for the Zr- and Hf-homologues confirmed for both compds. isotypism and revealed defects in the Ni sites and to a lesser extent also in the Al sites: ZrNi2-xAl5-y, x = 0.4, y = 0.4 and HfNi2-xAl5-y, x = 0.5, y = 0.2. The crystallog. relations among the structure types of Cu, TiAl3, ZrNi2Al5 and Zr(Ni,Ga)7 have been defined in terms of a Baernighausen scheme.
- Organisation(s)
- Department of Physical Chemistry, Department of Mineralogy and Crystallography
- External organisation(s)
- Czech Academy of Sciences, Eidgenössische Technische Hochschule Zürich
- Journal
- Intermetallics
- Volume
- 19
- Pages
- 1340-1347
- No. of pages
- 8
- ISSN
- 0966-9795
- DOI
- https://doi.org/10.1016/j.intermet.2011.03.028
- Publication date
- 2011
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 104017 Physical chemistry, 105113 Crystallography
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/d092806b-f519-464b-9a0f-eda8b2e4904b