Patent ID: 7431197

Claim:
A method of fabricating a hollow mechanical part by diffusion welding and superplastic forming, the method comprising the following steps: a) providing at least two primary parts of superplastic material, said primary parts having two faces and a periphery; b) providing an anti-diffusion substance and depositing said anti-diffusion substance in a predefined pattern on at least one face of said two faces of said primary parts; c) stacking-up and assembling said primary parts together at their said periphery, with the exception of a passage-forming location, said primary parts forming a stack and defining between them a cavity, said at least one face being placed facing into said cavity; d) diffusion welding the stack under isostatic pressure; e) placing the welded assembly in a mold; and f) raising said mold to the superplastic forming temperature and injecting an inert gas at the superplastic forming pressure via said passage into said cavity, thereby causing the stack to inflate and implementing superplastic forming, enabling a blank of the mechanical part to be obtained; wherein step b) is performed in application of the following sequence of operations: b1) applying a layer of anti-diffusion substance comprising a powder over the entire surface of said at least one face of the primary parts; b2) localized sintering of the anti-diffusion substance, without melting the powder, in said predefined pattern by the heating that results from localized application of a laser beam directly onto said powder along a track made up of at least one zone prior to the stacking-up, thereby producing, in said at least one zone, both bonds between the particles of powder and also a diffusion phenomenon between the particles of powder and the material of said at least one face of the primary part; and b3) removing the anti-diffusion substance from regions that are not subjected to the laser beam.