Manufacturing and Comparison of Sr Modified or Unmodified AlSi12 Eutectic Alloy Matrix Unimodal and Bimodal Composite Metal Foams

Metallic foams are designed to be generally used by the transportation industry as energy-absorbing reinforcements in bumper panels or as permanent cores for weight reduction. In composite metal foams (CMFs), the second phase is usually formed by hollow spheres or closed-wall porous materials responsible for the gas (void) intake. Herein, three types of samples are compared: CMFs with unimodal small, unimodal large, and bimodally mixed small and large ceramic hollow spheres. Unmodified AlSi12 or Sr modified AlSi12 alloy is infiltrated between the spheres with low-pressure infiltration to form the cellular structure. The effect of Sr modification on the matrix material properties and the matrix-filler interface layer is investigated. The samples are evaluated and compared based on microstructural analysis and standardized compressive tests; the fracture mechanism of the structure is analyzed using computed tomography measurements at different deformation states. The aim of this research is to develop high-performance unimodal and bimodal CMFs, which have better specific mechanical properties than conventional metal foams, and to investigate the effect of Sr modification on the material properties. With these foams, additional weight reduction and higher energy absorption can be achieved, primarily used as automotive components.