Comparison of orthorhombic and alpha-two titanium aluminides as matrices for continuous SiC-reinforced composites

Journal Article · Wed Jun 01 00:00:00 EDT 1994 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

DOI:https://doi.org/10.1007/BF02652301· OSTI ID:7085192

Smith, P R ^[1]; Graves, J A; Rhodes, C G ^[2]

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1. Air Force, Wright Patterson AFB, OH (United States). Metals and Ceramics Div.
2. Rockwell International Science Center, Thousand Oaks, CA (United States). Dept. of Materials Science

The attributes of an orthorhombic Ti aluminide alloy, Ti-21Al-22Nb (at. pct), and an alpha-two Ti aluminide alloy, Ti-24Al-11Nb (at. pct), for use as a matrix with continuous SiC (SCS-6) fiber reinforcement have been compared. Foil-fiber-foil processing was used to produce both unreinforced ( neat'') and unidirectional SCS-6'' reinforced panels. Microstructure of the Ti-24Al-11Nb matrix consisted of ordered Ti[sub 3]Al ([alpha][sub 2]) + disordered beta ([beta]), while the Ti-21Al-22Nb matrix contained three phases: [alpha][sub 2], ordered beta ([beta][sub 0]), and ordered orthorhombic (O). Fiber/matrix interface reaction zone growth kinetics at 982 C were examined for each composite system. Although both systems exhibited similar interface reaction products (i.e., mixed Ti carbides, silicides, and Ti-Al carbides), growth kinetics in the [alpha][sub 2] + [beta] matrix composite were much more rapid than in the O + [beta][sub 0] + [alpha][sub 2] matrix composite. Additionally, interfacial reaction in the [alpha][sub 2] + [beta] composite resulted in a relatively large brittle matrix zone, depleted of beta phase, which was not present in the O + [beta][sub 0] + [alpha][sub 2] matrix composite. Mechanical property measurements included room and elevated temperature tensile, thermal stability, thermal fatigue, thermomechanical fatigue (TMF), and creep. The three-phase orthorhombic-based alloy outperformed the [alpha][sub 2] + [beta] alloy in all of these mechanical behavioral areas, on both an absolute and a specific (i.e., density corrected) basis.

• OSTI ID: 7085192
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Vol. 25:6; ISSN 0360-2133
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
COMPOSITE MATERIALS
NIOBIUM ALLOYS
SILICON CARBIDES
TITANIUM BASE ALLOYS
EXPERIMENTAL DATA
MATRIX MATERIALS
ALLOYS
CARBIDES
CARBON COMPOUNDS
DATA
INFORMATION
MATERIALS
NUMERICAL DATA
SILICON COMPOUNDS
TITANIUM ALLOYS
360602* - Other Materials- Structure & Phase Studies
360102 - Metals & Alloys- Structure & Phase Studies
360603 - Materials- Properties