Thermo-plastic expansion of amorphous metallic foam

Amorphous Pd_(43)Ni_(10)Cu_(27)P_(20) foam is produced at 38%, 49%, and 70% porosity by isothermally expanding a 25%-porosity amorphous precursor in the supercooled liquid state for varying durations. The foam morphologies exhibit good spatial homogeneity as well as good size uniformity of bubbles, which is a consequence of the high viscosity of the supercooled liquid state which inhibits floatation and dampens the growth kinetics. The expansion capability of amorphous metals into high-porosity foam demonstrated in this study is attributed to the plastic deformability of the supercooled liquid state, which enables large plastic membrane elongations during foaming.