Thermodynamic modeling of intermetallic compounds in the Ni-Nb system

Journal Article · Sat Feb 01 04:00:00 EST 1992 · Scripta Metallurgica; (United States)

DOI:https://doi.org/10.1016/0956-716X(92)90622-L· OSTI ID:5636091

Kejun, Z; Zhanpeng, J ^[1]

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1. Dept. of Materials Science and Engineering, Central South Univ. of Technology, Changsha, Hunan 410083 (CN)

There are three intermetallic compounds in the Ni{sub 3}Nb, Ni{sub 6}Nb{sub 7}, and Ni{sub 8}Nb. Several attempts have been made to describe the Ni-Nb phase diagram by means of a thermodynamic approach. Kaufman and Nesor modeled the intermetallic compounds as line compounds. The compound Ni{sub 6}Nb{sub 7} was predicted to melt congruently, contrary to experimental data. In the work of Chevalier the homogeneity ranges of the compound phases were not considered, and the calculated (Ni) solvus overestimated the solubility of Nb. Although Ni{sub 6}Nb{sub 7} phase was described with a sublattice model, its nonzero width has not been predicted. This paper reports that a stoichiometric phase can usually be regarded as composed of two or more sublattices, the sites of each one being occupied by a certain element. If the phase has a small range of homogeneity, different species, which are sufficiently similar in size, shape, electronegativity, etc., may form mixtures on several of the sublattices.

• OSTI ID: 5636091
• Journal Information: Scripta Metallurgica; (United States), Journal Name: Scripta Metallurgica; (United States) Vol. 26:3; ISSN 0036-9748; ISSN SCRMB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
360104 -- Metals & Alloys-- Physical Properties
ALLOYS
DIAGRAMS
INTERMETALLIC COMPOUNDS
NICKEL ALLOYS
NICKEL BASE ALLOYS
NIOBIUM ALLOYS
PHASE DIAGRAMS
PHYSICAL PROPERTIES
STOICHIOMETRY
THERMODYNAMIC PROPERTIES