Manufacturing of open-cell aluminum foams via infiltration casting in super-gravity fields and mechanical properties

Replicated open-cell aluminum foams were produced by infiltration casting in super-gravity fields. Infiltration of preforms packed by NaCl particles with different sizes was conducted to demonstrate the technical feasibility of this method. The relative densities between 0.25 and 0.34 of the aluminum foams were obtained by varying the NaCl particle size of the preform from 600 to 200 μm. Increasing the gravity coefficient (G) increased the centrifugal pressure (P(c)) and correspondingly improved the relative densities and structural integrity of the resulting foams. As P(c) increased, the aluminum foam exhibited a transition from a structure of smooth struts to a relatively complex structure where many protrusions extended inside the pores from the surface of the struts. Also, the specific relationship between the minimum centrifugal pressures necessary to produce self-standing aluminum foams and the NaCl particle size of the preform was established. The minimum centrifugal pressures of 32, 49 and 83 kPa were required for aluminum foams with pore sizes of 600, 400 and 200 μm, respectively. Preliminary results show that super-gravity infiltration is promising to be a practical manufacture process for replicated open-cell aluminum foams.