Aluminium foam sandwich panels composed of an AlSi8Mg4 foam core and 6082 alloy sheets (‘AFS’) are available now in sizes up to a few square metres. A problem in production is how to cope with non-uniformities of the foam structure. Non-destructive quality control methods are desired for possible large-scale application such as in the automotive industry and for safety-relevant parts. We have investigated large industrial AFS panels and used X-ray radiography as a method to identify weak spots in the foam core. For this purpose, we use the false colour representation of the standard deviation or the logarithm of the intensity values of the X-ray images as shown in Figure 1 in order to identify possible defects.
For samples in which defects have been identified, the correlation with failure in tensile and bending tests has been investigated. The properties of a large number of samples tested in compression, tension and bending have been determined and presented in property tables. Furthermore, the protective effect of the AFS has been tested in impact and crash scenarios. We conclude that with X ray radiography we can identify flawed and potentially weak. In 50% of all tensile test samples, no such defects are discovered and the foams appear uniform. In the other cases defects occur. Of these about 50 % give rise to a predictable localised failure, in the other cases not.