The Effect of Prior Deformation on the Foaming Behavior of “FORMGRIP” Precursor Material

It is shown that extrusion of “FORMGRIP” precursor material prior to baking leads to accelerated foaming and finer, more uniform cell structures. This effect is correlated with microstructural observations made on the precursor materials and on the foams. It is thought that, while extrusion apparently does not extensively fracture the gas-generating hydride particles, it does induce some damage to their protective surface oxide layers. Removal of the porosity normally present in as-cast precursors may also be beneficial.