Evaluation of the Adhesive Bonding Processes Used in Helicopter Manufacture. Part 2. The Characterization of Adherend Surfaces.
GILLETTE CO RESEARCH INST ROCKVILLE MD
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Surfaces of titanium 6-aluminum, 4-vanadium alloy, commercial pure titanium grade3, 2024 T-3 and 6061 T-6 aluminum alloys bare, and 2024 T-3 aluminum alloy cladwere examined at selected stages in the prebonding treatment of these metals.Variations in the film morphology were observed directly in a scanning electronmicroscope, and, after removal, in a transmission electron microscope. Filmthickness measurements were made with transmission and reflectance interferencemicroscopes. Chemical compositions of these films were determined by photoelectronspectroscopy, electron diffraction, and nondispersive X-ray fluorescenceanalysis. Contact angles and surface potential measurements were also used tocharacterize these metal surfaces. The results obtained suggest that bondingdifferences with the variously treated titanium alloys were caused by variationsin the crystalline structure of the titanium dioxide, whereas bonding differenceswith the aluminum alloys were caused by variations in surface hydration, filmthickness, and surface morphology. Author-PL
- Fabrication Metallurgy