J. Phys. Colloques
Volume 48, Numéro C3, Septembre 19874th International Aluminium Lithium Conference
|Page(s)||C3-801 - C3-807|
J. Phys. Colloques 48 (1987) C3-801-C3-807
FATIGUE CRACK PROPAGATION BEHAVIOR OF 2091 T8 AND 2024 T3 UNDER CONSTANT AND VARIABLE AMPLITUDE LOADINGN. OHRLOFF1, A. GYSLER2 et G. LÜTJERING2
1 Messerschmitt-Bölkow-Blohm GmbH, Kreetslag 10, D-2103 Hamburg 95, F.R.G.
2 Metallkunde und Werkstofftechnik, Technishe Universität Hamburg-Harburg, Harburger Schlosstrasse 20, Postfach 901403, D-2100 Hamburg 90, F.R.G
The fatigue crack propagation behavior of the damage tolerant 2091 T8 was compared with that of 2024 T3. Constant amplitude tests were performed in vacuum, air, and NaCl solution at R = 0.175 and in air at R = 0.7. The variable amplitude tests included periodic underloads superimposed on constant amplitude tests at R = 0.7, and periodic overloads in combination with low R-ratio tests. In general it was found that the crack propagation resistance of 2091 was slightly inferior in the lower ƊK-region as compared to 2024, but somewhat better at higher ƊK-values. For both alloys predicted propagation rates based on constant amplitude tests were lower than the experimentally measured values with periodic underloads. Periodic overloads resulted in crack growth retardation.