Accession Number : AD0903400

Title :   Evaluation of the Adhesive Bonding Processes Used in Helicopter Manufacture. Part 3. Development of Improved Titanium Surface Treatments.

Descriptive Note : Technical rept.,

Corporate Author : GILLETTE CO RESEARCH INST ROCKVILLE MD

Personal Author(s) : Hamilton, Willard C. ; Lyerly, George A. ; Frohnsdorff, Geoffrey

Report Date : JUN 1972

Pagination or Media Count : 54

Abstract : Studies were made to determine whether rutile-free, anatase-containing oxide layers on CP titanium and titanium 6-aluminum, 4- vanadium alloy, could transform to rutile- containing layers on aging. Scanning electron microscope observations and electron diffraction showed that rutile could be detected in the oxide layers on some aged specimens which had been adhesively bonded, stressed, and exposed to high ambient temperatures and relative humidities. Since these specimens had been prepared using a phosphate-fluoride treatment known to give anatase-containing layers, it appeared that the conversion of anatase to rutile could take place in adhesively bonded joints. Further, it appeared that the anatase-rutile conversion was associated with bond failure. In attempts to stabilize anatase in oxide layers against conversion to rutile, the phosphate-fluoride treatment was modified by inclusion of salts of likely stabilizing ions in various steps of the treatment. In some cases, the contents of the ions in the surface were markedly increased, and sometimes the morphology of the surface oxide layer was changed. On the basis of extended times to failure of stressed joints made using some of the modified surface treatments, it appeared that these surface treatments were beneficial. (Author-PL)

Descriptors :   *BONDED JOINTS), (*HELICOPTERS, MANUFACTURING), (*TITANIUM, ADHESIVES, TITANIUM ALLOYS, ELECTRON DIFFRACTION, SURFACES, TRANSFORMATIONS, CRYSTALS, STABILITY, STRESSES, ELECTROLYSIS, RUTILE, FAILURE(MECHANICS), DIOXIDES, ELECTRON MICROSCOPES, OXIDES, X RAY DIFFRACTION, AGING(MATERIALS), PHOSPHATES, FLUORIDES, FILMS.

Subject Categories : Helicopters
      Adhesives, Seals and Binders
      Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE