Abstract: The influence of the gas chamber volume and the number of orifices of gas injection device on pore size of aluminum foams in the gas injection foaming process are studied. The effect of the gas chamber volume on bubble size and the formula for calculating the bubble size under low and intermediate gas flow rate are summarized. It is found that with the decreasing of the gas chamber volume the pore size of the aluminum foams decreases apparently by using a chamber adjustable gas supplying system. Based on the experimental data, suitable correction factors for calculating the pore size of the aluminum foams in the gas injection foaming process are presented. The experimental results also show that the aluminum foams with small pores can be fabricated by the gas injection device with more orifices when the gas chamber volume keeps a constant. To explain this phenomenon, the conception of “effective gas chamber volume” is proposed, which is defined as the quotient of the apparent volume divided by the number of the effective orifices. The values calculated with the effective gas chamber volume and the correction factors presented in this paper agree with the experimental data.

Key words: Aluminum foam, Bubble formation, Gas chamber volume, Gas injection