Fabrication of Aluminum Foams with Fine Cell Structure under Increased Pressure

Foaming of aluminum melts containing titanium hydride powder is processed under increased pressure. The real-time foam expansion height of aluminum melts is recorded and the cell structure of foam specimens is characterized. It is found that the loss of foaming gas to ambient environment during foaming process is reduced when foaming under increased pressure. Bubble coalescence is slowed down when pressure increases, leading to a significant decrease in mean cell size and its distribution range. The mean cell wall thickness also significantly reduces when foaming at increased pressure, which changes the correlation between mean cell size and foam density.