Fatigue crack propagation in a particulate-reinforced metal-matrix composite at room and elevated temperature

Conference · Fri Dec 31 04:00:00 EST 1993

OSTI ID:143680

Healy, J C; Beevers, C J ^[1]

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1. Univ. of Birmingham (United Kingdom)

The fatigue crack growth behavior of an aluminium alloy, 2618, and a composite material, 2618 reinforced with 15 vol. % silicon carbide particulate, has been investigated at room temperature and at 180{degree}C. The composite material has higher threshold stress intensity for long crack growth and superior resistance to fatigue crack growth at room temperature. There is evidence to support the view that asperity induced crack closure promoted by the particulate and causing fracture surface mismatch is more effective than the closure mechanism operating in the unreinforced material. Increasing the temperature to 180{degree}C resulted in lower threshold values and increased fatigue crack growth rates for both materials when compared to those at room temperature, with the unreinforced alloy having a higher threshold than the composite material, but faster growth rates in the Paris regime. Although crack growth in the composite material occurred at the matrix particle interface at both temperatures investigated, there was considerably less deflection of the crack tip observed during fatigue crack growth at 180{degree}C. Fractographic investigations revealed the length of test to be a factor governing the amount of oxide present on the fatigue fracture surface.

• OSTI ID: 143680
• Report Number(s): CONF-930246--; ISBN 0-87339-251-5
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM BASE ALLOYS
COMPOSITE MATERIALS
CRACK PROPAGATION
FATIGUE
SILICON CARBIDES