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Le comportement en fatigue sous différentes charges d’un alliage d’aluminium issu de la technologie AIRWARETMa été caractérisé sur métal brut et après traitement de surface. Plusieurs traitements sont étudiés et en particulier un traitement n’utilisant pas de Cr lors de la phase de décapage est comparé aux traitements conventionnels. Les résultats montrent que, sur métal brut, la résistance à la fatigue des alliages AIRWARETMest supérieure à celle d’alliages aéronautiques conventionnels des familles 2xxx et 7xxx, comme par exemple l’alliage 2024. Après traitement de surface, cette différence est réduite mais les alliages AIRWARETMdemeurent systématiquement plus résistants. L’utilisation d’un modèle de mécanique de la rupture élastique linéaire permet d’expliquer ce bon comportement par une taille moyenne de piqûres générées lors du traitement de surface réduite.

The Coelacanth, single survivor of the zoological group of Crossopterygians, in which is supposed to have appeared the ancestor of terrestrial Vertebrates, represents perfectly the emblematical living heritage of the earth. After the discovery of the first actual Coelacanth (in 1938), specimens have been fished in Comoros waters. The archipelago considers it now as a national heritage. But the fish is endangered and the international community there is attempting to preserve it by creating a marine park. Consequently, the populations on its borders consider it both a local heritage and an economic opportunity for development. This paper explores the meaning that the expressions "world heritage" and "local heritage" have for the actors involved and analyses the problems raised by the management of a world heritage on a local scale, in a context of great poverty.

Local probing of the galvanic coupling between micrometer-sized Al2Cuphases and the surrounding aluminum-based matrix of a specially heat-treated 2011 alloy is investigated using a microcapillary electrochemical cell. The aging of an isolated Al2Cuparticle, i.e., selective dissolution of aluminum, is controlled by the aeration condition at the tip of the capillary due to the nature of the silicon membrane used as a gasket. The local electrochemical behavior of an isolated particle after aging confirms the mass transport control of the oxygen reduction on the galvanic coupling of the particle with the surrounding matrix.