Effect of Heating Rate of Foamable Precursors on Foaming Behavior of PM-Route Al Foams

The quality of foam aluminum made by powder metallurgy process mostly depends on the variation in temperature during the foaming, i.e., the heating rate. The heating rate has impact on the foaming of aluminum foam precursor. It has been found that critical heating rate exists in this way of making closed Al foams through analysis of the warming process of precursors at different foaming temperature processed by linear fitting method. Being foamed at 750 °C, the critical heating rate was 6.62 °C/s. The expected cell structure couldn't be obtained, and the foaming process could not be controlled well when the foaming temperature was above 800 °C or below 700 °C.