Production of homogeneous alloy articles from superplastic alloy particles

Claim 1

A process for reproducibly forming homogeneous articles from the constitutionally complex alloys which comprises: providing the alloys in the form of clean, cold-worked particulate material, with the degree of cold work in the particles being sufficient to cause recrystallization and a condition of superplasticity when the alloy is heated above its recrystallization temperature, the individual particles being substantially homogeneous in composition, having an effective particle size exceeding about 0.003 inch, and providing a density of at least about 15 percent of the theoretical alloy density; prior to extensive compaction, outgassing the particulate material in vacuum at high temperature, removing substantially all adsorbed and occluded gases therefrom; prior to extensive compaction, heating the particulate material to a temperature sufficient to cause recrystallization and a condition of superplasticity; compacting the degasified superplastic particulate material in vacuum at a temperature sufficient to provide interparticle bonding and further compacting the material to provide a unitary article of full theoretical density; and with the time at temperature prior to full compaction being confined to a duration less than that required for the formation, by an internal diffusion mechanism, of surface species on the particulate resistant to interparticle metallurgical bonding.