Influence factors of sound absorption properties of closed-cell aluminum foam

Closed-cell aluminum foam was prepared by the method of molten body transitional foaming process, and the sound absorption properties were studied from the aspects of cell diameter, perforation rate, cavity thickness and aluminum foil attached behind. The results show that at the same porosity, the sound absorption coefficient of closed-cell aluminum foam with larger cell diameter is larger than that with smaller cell diameter; the sound absorption coefficient of closed-cell aluminum foam increases obviously after being perforated, when the perforation ratios are 0.5%, 1% and 2%, the highest sound absorption coefficient can reach 0.53, 0.75 and 0.96 from 0.46, respectively; the sound absorption curves of closed-cell aluminum foams after being perforated show obvious sound absorption characteristic of Helmholtz resonator; with increasing the cavity thickness, the sound absorption coefficient increases under low-frequency region, and decreases under high-frequency region; the highest sound absorption coefficient increases slightly, but shows the trend of traveling to low-frequency region; the peak sound absorption characteristics disappear when the closed-cell aluminum foams are attached with aluminum foils, and the sound absorption coefficient shows increasing characteristic with in creasing frequency.