Ordering transformations in the Nb sub 3 Si phase in Nb-10Si alloy

Journal Article · Sat Aug 15 04:00:00 EDT 1992 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(92)90205-S· OSTI ID:6978492

Saqib, M; Srinivasan, R; Weiss, I ^[1]

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1. Dept. of Mechanical and Materials Engineering, Wright State Univ., Dayton, OH (US)

Although the Nb-Si equilibrium phase diagram has been investigated repeatedly, the eutectic and eutectoid temperatures, the equilibrium solubilities of Si in Nb at different temperatures and the stable and metastable phases on the Nb-rich side of the phase diagram are still uncertain. According to the most recent phase diagram, the equilibrium solidification path for hypo-eutectic alloys containing approximately 3.5 to 18.7% Si is liquid Nb-Si undergoing a eutectic transformation to Nb(Si) + Nb{sub 3}Si at 1920{degrees} C with the Nb{sub 3}Si phase further transforming by a eutectoid reaction to Nb + Nb{sub 5}Si{sub 3} at 1770{degrees} C. The calculated metastable extension of the phase boundaries on the Nb-rich side of the phase diagram by Lipschutz et al. indicates that upon suppression of the formation of the Nb{sub 5}Si{sub 3} phase, the intermediate phase, Nb{sub 3}Si becomes a congruently melting compound. In such a case the Nb{sub 3}Si phase does not undergo the above mentioned eutectoid decomposition, and is retained at room temperature. Recent investigations have shown that the Nb{sub 3}Si phase present in the Nb-10Si alloy (atomic %) undergoes ordering transformations. This paper reports for the first time ordering transformations in the Nb{sub 3}Si phase in the Nb-10Si alloy.

• OSTI ID: 6978492
• Journal Information: Scripta Metallurgica et Materialia; (United States), Journal Name: Scripta Metallurgica et Materialia; (United States) Vol. 27:4; ISSN SCRME
• Country of Publication: United States
• Language: English

Related Subjects

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& Refractories-- Structure & Phase Studies
ALLOYS
CRYSTAL STRUCTURE
DIAGRAMS
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EUTECTICS
MICROSTRUCTURE
NIOBIUM COMPOUNDS
NIOBIUM SILICIDES
ORDER-DISORDER TRANSFORMATIONS
PHASE DIAGRAMS
PHASE STUDIES
PHASE TRANSFORMATIONS
REFRACTORY METAL COMPOUNDS
SILICIDES
SILICON COMPOUNDS
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SOLUBILITY
SPACE GROUPS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 1000-4000 K
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