Accession Number : AD0480754

Title :   INVESTIGATION OF THE STRUCTURAL STABILITY OF WELDS IN COLUMBIUM ALLOYS.

Descriptive Note : Final rept. 1 Jul 64-30 Jun 65,

Corporate Author : GENERAL ELECTRIC CO CINCINNATI OH SPACE POWER AND PROPULSION SECTION

Personal Author(s) : Thompson, S. R. ; Young, W. R. ; Kearns, W. H.

Report Date : APR 1966

Pagination or Media Count : 132

Abstract : The second phase of a study of structural stability of welds in typical commercial Nb alloys B66, D43 and Cl29Y is reported. Effects of increased levels of the interstitial elements O and N on postweld aging kinetics and bend transition behavior were determined for welds in these alloys. The effect of yttrium, as an alloy addition, on structural stability of Nb weldments was investigated using W arc and electron beam joining techniques to prepare samples of Cl29Y alloy. Aging studies were conducted in the 1400 to 3000 F temperature range from 1 to 256 hrs. In Cl29Y alloy welds, complex aging phenomena were indicated in the 1400 to 1800F temperature range. In general, increased quantities of the interstitial elements N and O substantially reduced as-welded ductility, but produced only minor effects on post-weld aging kinetics. N additions caused greater reductions in ductility than O in equivalent amts. Heat-treating on non-contaminated welds of the 3 alloys resulted in welds which were ductile at room temperature, even after exposure to re-aging cycles that tended to produce maximum embrittlement without prior overaging treatments. Tests affirmed that delayed cracking can be encountered in hydrogen contaminated D-43 welds.

Descriptors :   *WELDS), (*NIOBIUM ALLOYS, ARC WELDS, STABILITY, MICROSTRUCTURE, IMPURITIES, OXYGEN, NITROGEN, YTTRIUM, INERT GAS WELDING, ELECTRON BEAM WELDING, HEAT TREATMENT, AGING(MATERIALS), COATINGS, BENDING, DUCTILITY, MECHANICAL PROPERTIES, FRACTURE(MECHANICS), TENSILE PROPERTIES, X RAY DIFFRACTION, HIGH TEMPERATURE.

Subject Categories : Properties of Metals and Alloys
      Couplers, Fasteners, and Joints

Distribution Statement : APPROVED FOR PUBLIC RELEASE