| 摘要 |
A process is described of forming a structure by diffusion bonding and superplastic forming at least one skin sheet ( 16,18 ) and at least one core sheet ( 10,12 ), the process comprising: a) forming a pack from the at least one skin sheet ( 16,18 ) and the at least one core sheet ( 10,12 ); b) placing the pack in a mould ( 20 ) and heating the pack to a temperature at which the sheets are capable of superplastic deformation; c) injecting a gas between the skin sheet ( 16,18 ) and the core sheet ( 10,12 ) to urge the skin sheet against an internal face of the mould ( 20 ) thereby forming a cavity ( 30 ) between the skin sheet ( 16,18 ) and the core sheet ( 10,12 ); d) injecting gas on the side of the core sheet ( 10,12 ) remote from the skin sheet ( 16,18 ) to urge the core sheet ( 10,12 ) against the skin sheet ( 16,18 ), e) maintaining gas pressure on the said side of the core sheet ( 10,12 ), thereby forming a diffusion bond between the skin sheet ( 16,18 ) and the core sheet ( 10,12 ); and f) maintaining a regulated pressure of helium in the cavity ( 30 ) between the skin sheet ( 16,18 ) and the core sheet ( 10,12 ) during at least part of step d). The use of helium in the cavity allows such gas trapped in a pocket gas between the skin sheet ( 16,18 ) and the core sheet ( 10,12 ) to diffuse through the core sheet to eliminate such pockets, which obstruct the formation of diffusion bonds in step e). |
