Crack propagation in corrosion fatigue of metal-matrix composites

Thesis/Dissertation · Sat Jan 01 04:00:00 EST 1983

OSTI ID:5495257

Yau, S S

The effect of aqueous environment on the fatigue crack propagation of several metal-matrix composites (MMC) has been investigated. The fatigue cracking behavior and mechanisms in Gr-Al, Al/sub 2/O/sub 3/-Al, and SiC-Al materials were determined. In only the SiC-Al MMC materials were meaningful crack propagation data (da/dN vs. ..delta..K) obtained. The other materials tended to exhibit cracking in the fiber/matrix direction, primarily at the interfaces. Environmental effects tended to raise da/dN at a given ..delta..K in SiC-Al about a decade, but there was no discernible difference between the effect of distilled water and 3.5% salt solution. Transitions in the da/dN curves over a range of ..delta..K were linked to microstructural features in a model containing the subgrain size and interwhisker spacing. An orientation dependence was discovered (which stemmed from preferred orientations developed during processing) in the SiC-Al MMC. Fractographic examination revealed the existence of whisker clumping and growth faults along the SiC whiskers, which could lead to stress concentrations and facilitate cracking in fatigue.

• Research Organization: North Carolina State Univ., Raleigh (USA)
• OSTI ID: 5495257
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360303 -- Composite Materials-- Mechanical Properties-- (-1987)
360305* -- Composite Materials-- Corrosion
Erosion
& Degradation-- (-1987)
ALUMINIUM
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AQUEOUS SOLUTIONS
CHALCOGENIDES
COMPOSITE MATERIALS
CORROSION FATIGUE
CORROSIVE EFFECTS
CRACK PROPAGATION
DISPERSIONS
ELEMENTS
FATIGUE
MATERIALS
MECHANICAL PROPERTIES
METALS
MIXTURES
OXIDES
OXYGEN COMPOUNDS
SILICON COMPOUNDS
SILICON OXIDES
SOLUTIONS