The fatigue properties of 1100 aluminum in reverse bending were studied at vacuum levels varying from lo-' torr to atmospheric pressure. A substantial increase up to ten-fold in fatigue life was observed at pressures below 1O-2 torr which could be related to retardation of the crack propagation phase of the fatigue process.
The increase in fatigue resistance was attributed to the related kinetics of residual 0, and H,O gas adsorption at crack surfaces and fatigue crack growth.
Changes in the fatigue life and transition pressure effect with varying cyclic stress frequency and bend stress amplitude were interpreted in terms of the interaction between crack propagation and gas adsorption rates. COMPORTEMENT A LA FATIGUE DE L'ALUMINIUM DANS LE VIDE Les propri&&s de fatigue en flexion alter&e de l'aluminium 1100, ont Bti: Btud%es dans des niveaux de vide variant B partir de lo-' torr jusqu'21 la pression atmosphbrique. Un accroissement appr&iable, jusqu'i dix fois, de la vie & la fatigue a QtB observ8 aux pressions infbrieures B 10e2 torr; ceci pourrait i%re relit5 au retardement de la phase propagation des fissures du processus de fatigue. L'accroissement de la r&stance B la fatigue a QtB attribub & la relation entre la cin&ique d'adsorption d'0, et H,O