The ternary system:Aluminum--iron--praseodymium

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Journal of Materials Research; (USA)

DOI:https://doi.org/10.1557/JMR.1991.0053· OSTI ID:5778897

Klesnar, H; Rogl, P ^[1]

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1. Institut fuer Physikalische Chemie der Universitaet Wien, A-1090 Wien, Waehringerstrae 42, Austria (AT)

Phase equilibria in the ternary system Pr--Fe--Al have been established in an isothermal section at 800 {degree}C from room temperature x-ray powder diffraction analysis of about 50 alloys, which were melted, annealed at 800 {degree}C, and quenched. Phase equilibria are characterized by the formation of rather extended homogeneous regions, i.e., by a random substitution of Fe/Al in Pr(Al{sub 1{minus}{ital x}}Fe{sub {ital x}}){sub 2}, 0{le}{ital x}{le}0.15, in Pr{sub 2}(Fe{sub 1{minus}{ital x}}Al{sub {ital x}}){sub 17}, 0{le}{ital x}{le}0.65, as well as by the formation of at least four ternary compounds. Whereas the existence of PrFe{sub 4}Al{sub 8} with the CeMn{sub 4}Al{sub 8}-type structure has been confirmed, there were no indications for a compound PrFe{sub 6}Al{sub 6}'' earlier claimed to crystallize with the ThMn{sub 12}-type structure. Pr{sub 6}(Fe{sub 1{minus}{ital x}}Al{sub {ital x}}){sub 14}, 0.16{le}{ital x}{le}0.36 with a homogeneous region parallel to the Fe--Al binary, was found to be isotypic with the La{sub 6}Co{sub 11}Ga{sub 3}-type of structure. Pr-rich alloys are liquid at 800 {degree}C, and all the alloys Pr{sub 2}(Fe{sub 1{minus}{ital x}}Al{sub {ital x}}){sub 17} with aluminium concentrations less than 5 at. % Al ({ital x}{similar to}0.07) enter a two-phase equilibrium with the Pr-rich liquid. At temperatures below 800 {degree}C, alloys with compositions close to 30 at. % Pr and 5 at. % Al show a further ternary phase on solidification, whose crystal structure is related to the La{sub 6}Co{sub 11}Ga{sub 3}-type. PrFe{sub 2}Al{sub 8} is a new representative of the CeFe{sub 2}Al{sub 8}-type structure. The crystal structure of the ternary compound richest in Al, PrFe{sub 2}Al{sub 10}, has not been solved yet.

• OSTI ID: 5778897
• Journal Information: Journal of Materials Research; (USA), Journal Name: Journal of Materials Research; (USA) Vol. 6:1; ISSN JMREE; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOY SYSTEMS
ALLOYS
ALUMINIUM ALLOYS
ANNEALING
COHERENT SCATTERING
CRYSTAL STRUCTURE
DIFFRACTION
HEAT TREATMENTS
IRON ALLOYS
PHASE STUDIES
POWDERS
PRASEODYMIUM ALLOYS
RARE EARTH ALLOYS
SCATTERING
TERNARY ALLOY SYSTEMS
VERY HIGH TEMPERATURE
X-RAY DIFFRACTION