Method for diffusion bonding of alloys having low solubility oxides

[54] METHOD FOR DIFFUSION BONDING OF ALLOYS HAVING LOW SOLUBILITY OXIDES

[75] Inventors: James R. Kennedy, Huntington;

Edmund Y. Ting, Oyster Bay, both of
N.Y.

[73] Assignee: Grumman Aerospace Corporation,
Bethpage, N.Y.

[21] Appl. No.: 928,898

[22] Filed: Not. 10,1986

[51] Int. Q.* B23K 20/22; B23K 20/24

[52] U.S. a 228/157; 228/193;

228/203; 228/205; 228/263.17; 228/172;

148/11.5 A

[58] Field of Search 228/157, 193, 118, 265,

228/172, 205, 263.17, 203; 148/11.5 A

[56] References Cited

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1151404 4/1985 U.S.S.R 228/193

OTHER PUBLICATIONS

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Strengths of Diffusion Bonded Al-Alloys", Int. Conf.
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J. Pilling and N. Ridley, "Solid State Bonding of Super-
plastic AA7475", Materials Science and Technology,
May 1987, vol. 3, pp. 353 to 358.

Primary Examiner—Nicholas P. Godici
Assistant Examiner—Samuel M. Heinrich
Attorney, Agent, or Firm—Richard G. Geib; Daniel J.
Tick; David Aker

Diffusion bonding of surface layers of an alloy, such as an aluminum alloy, having surface oxides of low solubility in the alloy includes treating the surface layers to be bonded to remove existing surface oxide coatings, and diffusion bonding the surface layers to one another by placing the alloy to be bonded under sufficient pressure to cause disruption of the oxide coatings by localized surface deformation of the alloy, enhanced by a superplastic microstructure, without substantial deformation of the alloy, i.e., macroscopic deformation approaching zero percent, while heating the alloy in a non-oxidizing atmosphere for a time sufficient for diffusion bonding to occur. The alloy may be treated so that at least the surface layers thereof have a fine grain structure of the type associated with superplastic forming properties. Components may be formed by diffusion bonding and superplastic forming.

27 Claims, 18 Drawing Figures