Numéro : 1959 - Year : 1984
Creep crack propagation in aeronautical alloys: study of a aluminium alloy
Ph. BENSUSSAN, Ingénieur de l'Armement
Ecole Nationale Supérieure des Mines de Paris
R. PELLOUX, Professeur, Department of Materials Science and Engineering , Massachusetts Institute of Technology
The propagation of macroscopic cracks by creep, fatigue and/or environment induced damage may limit the service life of high temperature metallic parts, such as jet engine blades and disks, or some components in hot sections of supersonic aircraft structures. The creep crack growth rates per unit time (da/dt) have been measured in 2219-T851 (formely NF A-U6MT) aluminium alloy at 175° c. This alloy is found to be creep brittle. A unique correlation is shown to exist between da/dt and the stress intensity factor (K) in a regime of quasi-steady or steady state crack growth under small scale yielding and plane strain conditions. There is no correlation with other loading parameters. All these results are in agreement with concepts of Fracture Mechanics of creeping solids. A discussion of the use of these experimental data in the estimation of the service life of parts containing cracks is presented.
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