Fabrication and characterization of closed-cell magnesium-based composite foams

Abstract Closed-cell AZ31 magnesium alloy foams with different percentages of hollow ceramic microspheres (CMs) are synthesized using modified melt foaming method. The distribution of CMs is investigated and also the effect of CMs on the foaming behaviors (specifically for porosity and pore size) and quasi-static compressive behaviors of Mg-based composite foams are characterized. The results show that CMs distribute in cell walls homogeneously and most of them are penetrated by magnesium alloy melt. In addition, the mean pore size declines with the increase of CMs percentage. Moreover, the overall porosity of the foams increases first and then decreases with the increase of CMs content, and the variation tendency is more obvious when the foaming temperature is lower (namely 680 °C). Besides, proper percentage of CMs changes the compression fracture mode of the foams from brittleness to ductility. OM/SEM/EDS/XRD detections and finite element analysis are applied to explain the reasons.