| 摘要 |
A die for superplastically forming a blank of superplastic material to make a part includes a die base enclosing a cavity having a topography shaped like the part, and a die lid shaped and sized to fit over the die base and engage a peripheral surface of the die base around the cavity. The die lid has an underside communicating with the die cavity and a recess opening in the underside positioned in the die lid to overlie an area on the die cavity at which the blank othewise would experience insufficient thinning during superplastic forming of the blank. Gas vents are provided in the base and the lid for first delivering forming gas under pressure into the cavity to preform the blank into the lid recess to prethin the blank in the thick areas, and thereafter vent the cavity gas pressure and deliver forming gas under pressure to the lid to form the blank into the cavity in the die base. The blank is prethinned in the recess and delivers areas of the blank unthinned to areas of the cavity which otherwise would experience excessive thinning.
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