Characterization of silicide precipitates in primary Nb phase in Nb-10% Si in-situ composites

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Scripta Metallurgica; (United States)

DOI:https://doi.org/10.1016/0956-716X(91)90199-B· OSTI ID:5343639

Cockeram, B; Saqib, M; Omlor, R; Srinivasan, R; Weiss, I ^[1]; Matson, L E ^[2]

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1. Dept. of Mechanical and Materials Engineering, Wright State Univ., Dayton, OH (US)
2. Wright Research and Development Center-Materials Lab., Wright-Patterson AFB, OH (US)

Intermetallic compounds based on refractory metals such as Nb, Mo and W have high melting points ({gt}1700{degrees} C) and retain their strength and stiffness to a very high temperature ({gt} 1000{degrees} C) making them candidate materials for very high temperature applications. Intermetallic compounds are extremely brittle, and successful implementation of these materials, therefore, depends on improved toughness both at room temperature and at elevated application temperatures. One possible method of increasing toughness is to form in-situ composites of the intermetallic compound and a metallic phase. A study of the interaction between the brittle intermetallic phase and the ductile metallic phase is important because these in-situ composites attain their toughness from the morphological distribution the two phases. The Nb- Si binary system has been chosen as a model system for this study. The equilibrium phase for alloys over the composition range 0 to 37.5 (atomic) percent Si, at temperatures from room temperature to 1700{degrees} C are the terminal metallic Nb phase and the intermetallic compound Nb{sub 5}Si{sub 3}. The solubility of Si in Nb is small ({lt}0.1%) below 1200{degrees} C. There is an increase in solubility up to the eutectoid temperature above which the compound Nb{sub 3}Si is stable. The maximum solubility of Si in Nb occurs at the eutectic temperature. This paper deals with the identification and characterization of the precipitates in the primary Nb phase in Nb-10 (atomic) prcent Si alloy.

• OSTI ID: 5343639
• Journal Information: Scripta Metallurgica; (United States), Journal Name: Scripta Metallurgica; (United States) Vol. 25:1; ISSN 0036-9748; ISSN SCRMB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
360602 -- Other Materials-- Structure & Phase Studies
ALLOYS
BRITTLENESS
CHEMICAL COMPOSITION
COMPOSITE MATERIALS
ELEMENTS
INTERMETALLIC COMPOUNDS
MATERIALS
MECHANICAL PROPERTIES
MELTING POINTS
METALS
MOLYBDENUM
NIOBIUM ALLOYS
NIOBIUM COMPOUNDS
NIOBIUM SILICIDES
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
REFRACTORY METAL COMPOUNDS
REFRACTORY METALS
SEMIMETALS
SILICIDES
SILICON
SILICON ALLOYS
SILICON COMPOUNDS
SOLUBILITY
TENSILE PROPERTIES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TRANSITION TEMPERATURE
TUNGSTEN