Adhesion in sandwiches with aluminum foam core
Fast moved machine tool assemblies should be light and stiff. By reason of the lightweight construction and the dynamical loads these assemblies are susceptible to vibrations very often. Aluminium foam sandwiches are laminates with an aluminium foam core and compact cover sheets. The foam cores have a high energy absorption. Machine tool assemblies constructed with aluminium foam sandwiches offer very high flexural stiffness together with comparatively light weight. Vibrations generated by machining are damped very well due to the cellular structure of foam. For industrial applications of sandwiches with aluminum foam core it is necessary to obtain adhesive forces above the strength of the aluminum foam. This condition will be fulfilled when in case of loading the foam will be destroyed and not the connection between cover sheet and foam core. Aim of the following examinations was to determine the bond strengths of different sandwiches. For this reason, the materials of the cover sheets and of the foam, as well as the surface properties of the cover sheets were varied. The alloys AlMg1Si0.5 and AlSi10 have been used for the foam core. By using drum peeling tests according to DIN 53295 the adhesion of different combinations of different cover sheet/aluminum foam have been analyzed. Good adhesion have been reached for sandwiches with cover sheets made of low-alloy steel, in connection with AlMg1Si0.5 core layers. Surface treatment (e.g. blast cleaning) leads to increased adhesion. Clearly worse results were obtained with the alloy AlSi10 and high-grade steel cover plates, except for the high-grade steel 1.4713 for which in combination with the alloy AlMg1Si0.5 good adhesion was obtained, too. Reproducible and high adhesive strength within compound structures is necessary for launching serial production of these semi-finished foam products. For the future there will be focus on pursuing analyses based on the present results.