Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Failure analysis in metal adhesive joints of aircraft components with the analytical electron microscope

: Schäfer, H.

Brockmann, W.; Wolitz, K.; Schäfer, H. ; Fraunhofer-Institut für Angewandte Materialforschung -IFAM-, Bremen:
BASTART '87. Bonded aircraft structures, technical application and repair techniques. Metal-metal-bonding and advanced composites. Proceedings
Bremen, 1987
BASTART <2, 1987, Travemünde>
Fraunhofer IFAM ()
analysis; bonded aircraft structure; durability; electron microscopy; metal adhesive joint; quality control

Aircraft structural materials like the aluminium alloy Al 2024 require a surface pretreatment by chemical processes prior to bonding. Investigations in microareas like boundary zones in adhesive joints require techniques with high resolution for imaging and small spot sizes (nm-range) for microanalytical systems with sufficient detection efficiency. Today these specifications are fulfilled best by an equipment which uses electrons for excitation of the specimen material because these can be imaged by electromagnetic lenses and may be focussed to a very small probe. Some Airbus A 300 aircrafts equipped with US-engines had delaminations of aluminium-honeycomb adhesive joints at the fan reverser support assemblies. Macroscopically the aluminium sheets showed adhesive failure in some areas but no evidence of corrosion. Other areas, however, seemed to be intact and the adhesive still was banding at the surface. For the following examinations with the AEM crosscuts of the metal-polymer joint s were prepared of the areas which still were coated by the adhesive. The investigations were carried out in order to clarify if the manufacture of these compounds had been related with mistakes in the course of the surface pretreatment process.