The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adem.202100695.

In this study, filtration of aluminum alloy (Al) with different weight fractions of SiC particles (SiCp) was investigated. Therefore, three different filter materials of 20 pores per inch (ppi) ceramic foam filters (CFF) were tested. A special three-chamber furan mold was used for the casting trials to provide uniform filling and flow conditions for the filtration process. Samples from sections of the gating system, as well as from the filter, were analyzed by optical light microscopy to determine the amount, size, and distribution of SiCp. A scanning electron microscope (SEM) with energy-dispersive X-ray spectroscopy (EDS) was used for obtaining the element distribution in the composite. The filtration efficiency increased by decreasing the weight fraction from 20 to 5% of SiCp and reached a significant particle reduction of over 90%. Investigations of CFFs with a weight fraction of 10% have shown a clogging effect and metal flow interruption through the 20 ppi filter. An oxide layer was detected around the respective SiCp in the EDS. Moreover, a strong accumulation effect was observed, indicated by a steadily flattening curve of the density functions after each additional remelting cycle of the same composite material.

Iron (Fe) is perceived as an accompanying impurity in aluminum silicon (AlSi) casting alloys. However, the formation of Fe-containing intermetallic phases, which mostly exhibit a plate-like morphology, impairs both the mechanical and casting properties. [1,2] This structural plate-like compound is referred to as the β-Al 4.5 FeSi phase. By increasing initial Fe content in the melt, the plate-like formation is promoted into a coarse lamellar morphology mainly due to diffusion. [3] Consequently, effective feeding with residual melt is hindered, and shrinkage porosity can be enhanced during solidification. [4][5][6] Furthermore, the platelike β-Al 4.5 FeSi morphology leads to stress concentrations at the coarse plate tips, significantly diminishing the casting ductility. [5,7,8] In fatigue crack propagation studies, the crack initiation site has been demonstrated on the plate-like β-morphology, where the plates can be either split longitudinally or completely separated during crack propagation. [1] Conversely, crack propagation at the star-like morphology is merely bypassed. [1]