Enhanced melt purification of M174 alloy via synergistic ultrasound-assisted ceramic foam filtration

M174 aluminum alloy is a key structural material for aerospace and automotive engine components, whose performance critically depends on melt purity. Traditional individual purification methods, such as standalone ultrasonic treatment or ceramic foam filtration, exhibit limited effectiveness in removing pores and inclusions, while studies on their combined application remain scarce. This study introduces a synergistic UST–CFF purification process and systematically investigates the effects of ultrasonic power and ceramic foam filter pores per inch (PPI) on purification efficiency. The results demonstrate that under optimized parameters (3 kW UST, 20 PPI CFF), the UST–CFF treatment achieves superior purification performance: the density index decreases to 0.78%, and the porosity volume of the ingot is reduced to 0.09 cm³/100 g, significantly outperforming untreated (3.24%, 1.54 cm³/100 g), standalone UST (1.86%, 0.46 cm³/100 g), and standalone CFF (2.35%, 1.01 cm³/100 g) samples. Microstructural analysis confirms effective removal of Al₂O₃ inclusions and substantial reduction in pore defects, leading to remarkable improvements in mechanical properties. After UST–CFF treatment, the alloy exhibits an ultimate tensile strength of 202.2 MPa, which is higher than those of untreated and individually treated samples. This study establishes a feasible industrial pathway for producing high-performance M174 alloy via UST–CFF synergistic melt purification.