Monitoring the failure mechanisms in metal matrix syntactic foams during compression by acoustic emission

Syntactic foam containing hollow ceramic spheres with an average outer diameter of 1.45 mm and wall thickness of 58 µm was produced using the pressure infiltration technique. This paper presents the analysis of the compressive deformation mechanisms of these syntactic foams using the acoustic emission (AE) technique. The active deformation mechanisms are determined by sequential k-means analysis of the AE data. The analysis revealed three dominant deformation mechanisms: plastic deformation of the cell walls, sphere fracture, and cell wall collapse. The AE results obtained are in good correlation with the findings of the visual inspection of the surface of the specimen, suggesting that the active deformation mechanisms in the whole volume of the specimen can be determined by this technique.