Phase diagram and thermodynamic properties of the yttrium--zinc system
The phase relations of the yttrium zinc system have been reexamined. A total of eight compounds have been identified by differential thermal analysis, metallographic and x-ray diffraction techniques. The three compounds YZn, YZn/sub 2/, and YZn/sub 8/./sub 5/ melt congruently at 1105, 1080, and 890/sup 0/C, respectively. The compounds YZn/sub 3/, YZn/sub 3/./sub 67/, YZn/sub 4/./sub 46/, YZn/sub 6/ and YZn/sub 12/ all decompose peritectically at 905, 896, 882, 872, and 685/sup 0/C, respectively. Three eutectics were found at 875/sup 0/C and 23.2 wt percent Zn, 1015/sup 0/C and 51 wt percent Zn and at 863/sup 0/C and 82 wt percent Zn. A polymorphic transformation was observed in the YZn/sub 2/ compound that proceeds at 750/sup 0/C in the yttrium rich region but drops to approximately 630/sup 0/C in the zinc rich region. The thermodynamic properties of the intermetallic compounds have been determined using the dewpoint method to measure the vapor pressure of zinc. The standard free energy relations vary from ..delta..G/sup 0/ (YZn) = -24,020 + 8.76T to ..delta..G/sup 0/ (YZn/sub 12/) = -85,940 + 48.61T cal/mole.
- Research Organization:
- Ames Lab., IA
- OSTI ID:
- 7273954
- Journal Information:
- Metall. Trans., A; (United States), Journal Name: Metall. Trans., A; (United States) Vol. 7:2; ISSN MTTAB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
COHERENT SCATTERING
DIAGRAMS
DIFFERENTIAL THERMAL ANALYSIS
DIFFRACTION
ENERGY
FREE ENERGY
INTERMETALLIC COMPOUNDS
PHASE DIAGRAMS
PHYSICAL PROPERTIES
SCATTERING
THERMAL ANALYSIS
THERMODYNAMIC PROPERTIES
X-RAY DIFFRACTION
YTTRIUM ALLOYS
ZINC ALLOYS