BASIC METALLURGY OF DIFFUSION BONDING.
Abstract
The stability of joints diffusion bonded with intermediate foils was studied for TZM, 90 tantalum-10 tungsten, B66, and TD-Nickel. Butt joints and lap joints were bonded with two thicknesses of intermediate foil and mechanical properties in the as-bonded condition were compared with those after long-time exposures to temperatures up to 3000 F. Metallographic and electron microprobe data were correlated with tensile and shear data gathered in joint evaluation tests. The effect of thickness of the intermediate foil on the strength of butt bonded joints was studied. Chemical analyses were used to follow the movement of carbon between TZM and the intermediate foil. Bonding systems were developed for 0.25-inch diameter rod and 0.060-inch sheet. Two thicknesses of intermediate foil were used in each system. With the exception of TD-Nickel the systems were evaluated in the test range -320 to 3000 F in the as-bonded condition and after 10-hour exposures up to maximum service temperatures. Although the TD-Nickel alloy has been successfully bonded without an intermediate, a successful bonding system using an intermediate foil was not developed. Joints without intermediate foils were not studied on this program. Diffusion of interstitial elements between the alloy and the intermediate foil was shown to be the most important factor affecting joint stability. Foils that form interstitial 'sinks' are particularly detrimental to joint stability. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1965
- Accession Number
- AD0474074
Entities
People
- A. G. Metcalfe
- J. S. Dunning