Effects of Surface Finish on the Solid State Welding of High Strength Aircraft and Aerospace Aluminium Alloys
This paper reports some effects of different surface preparation methods on the bond quality of diffusion welded Aluminium alloy sheets. The preparation methods included grinding and steel brushing as well as “RF sputter cleaning” with a subsequent sputter deposition of Cu, Ag or Au.
Surface and depth profile analyses were carried out by means of Auger-Electron-Spectroscopy (AES) and Glow Discharge Source (GDS) Plasma-Emission-Spectroscopy in order to verify the surface characteristics of the sheets to be bonded. For the welding experiments a DB-Hot-Press with a vaccum chamber has been developed especially for the Diffusion Bonding of high strength Al-sheets. The bonding process is characterized especially by the application of the weld pressure during the heating phase and by a controlled cooling phase.
Mechanical tests were carried out by shear testing and peel testing at room-temperature and SPF-temperature (516°C). Additionally metallographic and fractographic methods were used for a further characterization of the joints. The results show that basic material properties can be obtained in the solid state welding by an optimum surface treatment and optimized bonding parameters.
KeywordsShear Strength Coated Bond Bond Quality Diffusion Bond Bond Shear Strength
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