Low-density, open-cell nickel base superalloy foams have been synthesized b
y a high-rate, electron beam-directed vapor deposition process and their me
chanical properties evaluated. The deposition process uses an open-cell pol
ymer foam template upon which is deposited a metal alloy coating. The elect
ron beam evaporated flux was entrained in a rarefied transonic gas jet and
propagated along the flow stream lines through the polymer structure. After
vapor deposition, the polymer template was removed by low-temperature ther
mal decomposition. The resultant ultralightweight metal foams consisted of
a three-dimensional open cell, reticulated structure possessing hollow tria
ngular ligaments with relative densities of <3%. Their mechanical integrity
was increased by either pressureless or transient liquid phase sintering.
The mechanical properties of these ultralightweight metal foams were compar
able to theoretical predictions for open-cell, reticulated foams.