Stabilizing intermetallic phases within aluminum foam

Because of ambiguity in microstructural characterization of cell wall material of Alporas® aluminum foam in literature until now, the study was focused to contribute to the examination of microstructural variability, and to reveal differences in distribution of stabilizing intermetallic phases in microstructure and their identification. It was shown that the microstructure consists of four precipitates distributed in α-Al matrix. The energy-dispersive X-ray spectroscopy revealed the presence of precipitates with compositions of AlCa, AlCaTi, AlCaFe and AlCaTiFe. However, selected area electron diffraction and X-ray diffraction confirmed that all analyzed precipitates could be indexed only in terms of tetragonal Al₄Ca or cubic Al₂₀CaTi₂. It was shown that the distribution of intermetallic compounds in cell wall material is affected by height position in the foamed block — they are either distributed along the grain boundaries of α-Al in the bottom area or they are dispersed in the α-Al matrix in the middle and top area.