Sheet materials are superplastically formed and optionally diffusion bonded into structures, by directly electrically resistance heating the sheets and forming them with a controlled gas-mass flow while the dies (362) in which they are formed may remain relatively cool. The dies include electrodes and thermocouples placed therein, and gas interface ports that connect to the sheets to be formed to allow rapid formation of structures. Some of the gas interface ports may become sealably attached to the part during the formation process so that the structures may be removed from the dies hot, thus allowing a high die throughput.