Thermo-plastic expansion of amorphous metallic foam

Amorphous Pd43Ni10Cu27P20 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. (C) 2006 Published by Elsevier B.V.