Response of Alumina Foam to Tensile Mechanical Loading Including Stress Concentrator Effect

Tensile test methodology for ceramic foams has been elaborated and test specimens of different dimensions and those containing central sharp notch (simulating a crack) were tested. Tested material was commercially available alumina based ceramic foam commonly used as filters of light metals melts. The foam cell size used within this study was 60 PPI. The main aim of the investigation has been to prove experimentally whether there is any stress concentration effect in the open cell structures. The fracture load (tensile strength) values were analysed and, in particular, the samples containing central sharp notch and comparable unbroken cross-section were compared with the unflawed samples. Specimens with central through thickness sharp notch have shown demonstrably the strength values comparably lower than the strength level of samples having the same cross-sectional area without stress concentrator. The explanation has been seen in stress concentration effect beneath the internal sharp notch root.