Interface considerations in Al2O3/NiAl composite. Final report

Technical Report · Thu Jul 01 00:00:00 EDT 1993

OSTI ID:5788314

Misra, A K

The fiber-matrix interface requirements in an Al2O3/NiAl composite were examined from theoretical considerations. Several factors that influence the interface bonding requirements were analyzed. These include: (1) residual stresses due to fiber-matrix coefficient of thermal expansion (CTE) mismatch; (2) matrix cracking stress at room temperature; (3) fracture toughness at room temperature; (4) load transfer from the matrix to the fiber and ultimate tensile strength at the use temperature; and (5) creep resistance at high temperature. A relatively weak fiber-matrix bond, with an interfacial shear strength of approximately 15-20 MPa, might be sufficient for attaining the desired mechanical properties in the fiber direction at the use temperature. A weak fiber-matrix bond is also beneficial for increasing the fracture toughness of the composite at room temperature. In contrast, a strong fiber-matrix bond is required to withstand some of the residual stresses resulting from the fiber-matrix CTE mismatch, which are not likely to be reduced significantly by interface coatings. A relatively strong bond is also beneficial in increasing the matrix cracking stress at room temperature. Various interface coating options to accommodate the conflicting bonding requirements were reviewed. One viable coating option is to incorporate a thick, ductile interface layer well bonded to both the fiber and the matrix.

• Research Organization: Sverdrup Technology, Inc., Brook Park, OH (United States)
• OSTI ID: 5788314
• Report Number(s): N-94-11202; NASA-CR-191167; E-8032; NAS-1.26:191167; CNN: NAS3-25266; RTOP 510-01-50
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
FIBERS
INTERFACES
MECHANICAL PROPERTIES
MATRIX MATERIALS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
COATINGS
CRACKS
CREEP
FRACTURE PROPERTIES
INTERMETALLIC COMPOUNDS
NICKEL COMPOUNDS
SHEAR
TENSILE PROPERTIES
THERMAL EXPANSION
ALLOYS
CHALCOGENIDES
EXPANSION
MATERIALS
OXIDES
OXYGEN COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360601* - Other Materials- Preparation & Manufacture
360603 - Materials- Properties