The ternary system Yb-Cu-Mg: Isothermal section at 400°C in the range from 0 to 67at.% Cu
- Author(s)
- Gerald Giester, Peter Franz Rogl, Adriana Saccone, S De Negri
- Abstract
Phase relations in the ternary system Yb-Cu-Mg have been established for the isothermal section at 400 C based on X-ray powder diffraction, metallog., SEM and EPMA techniques on about 30 alloys, which were prepd. in sealed Ta-crucibles followed by a homogenisation treatment. Phase equil. in Yb-Cu-Mg are characterized by the absence of Yb soly. in CuMg2 and of Mg soly. in YbCu2. In the compositional range 0-67 at. % Cu five ternary compds. were obsd. in addn. to the Cu-rich ternary phase that is already reported in the literature (.tau.1-YbCu9Mg2). The section Cu2Mg-YbCu2 shows an extended homogeneity range for binary Cu2Mg up to 8 at. % Yb where Mg atoms are substituted by Yb. At increasing Yb-content .tau.2-(Yb1-xMgx)Cu2 (ordered variant of the Cu2Mg-type) forms with a homogeneity region extending from x = 0.45 to x = 0.63. A ternary phase of stoichiometry Yb2Cu2Mg (.tau.3) was detected, whose crystal structure is still unknown. Three compds. were found to form near the concn. line with 66.7 at. % Yb: .tau.4-Yb4Cu1-xMg1+x (0 x 0.25, Gd4RhIn-type), .tau.5-Yb23Cu7Mg4 (almost stoichiometric, with a unique structure type) and .tau.6-Yb2CuxMg1-x (x = 0.2, structure still unknown). Atom order in the crystal structures of YbMg2 and .tau.5-Yb23Cu7Mg4 (Yb23Cu7Mg4-type; P63/mmc; a = 1.1866(2); c = 2.34371(5) nm) was detd. by direct methods from X-ray single crystal counter data.
- Organisation(s)
- Department of Mineralogy and Crystallography, Department of Physical Chemistry
- External organisation(s)
- Università degli Studi di Genova
- Journal
- Intermetallics
- Volume
- 16
- Pages
- 1285-1291
- No. of pages
- 7
- ISSN
- 0966-9795
- Publication date
- 2008
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105113 Crystallography
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/2718c96a-801a-42cd-a2cf-c6979e2adae8