Accession Number : AD0475017

Title :   THE TECHNOLOGY OF TANTALUM ALLOYS WITH MAXIMUM STRENGTH IN THE 3000 F TO 3500 F RANGE.

Descriptive Note : Technical rept. Jun 63-Dec 64,

Corporate Author : NATIONAL RESEARCH CORP NEWTON MA

Personal Author(s) : Douglass, R. W.

Report Date : APR 1965

Pagination or Media Count : 155

Abstract : The fabricability, ductility and weldability of the Ta-10W alloy was found to be sensitive to interstitial contamination. Less than 500 ppm of either carbon, oxygen or nitrogen resulted in a loss of fabricability and weldability. Interstitial tolerances were defined for various metallurgical conditions. Yttrium additions to Ta-10W in the range 30 to 500 ppm resulted in an increase in recrystallization temperature and a substantial reduction in grain growth at temperatures to 4000 F. Yttrium additions resulted in improved weldability in Ta-12W and Ta-14W alloys and in improved fabricability in alloys containing up to 16 per cent tungsten. Alloys in the Ta-W-Hf and Ta-W-Zr systems could be heat treated to improve strength at 3500 F. Alloys in the range Ta-1OW-1--2Zr were ductile as electron beam welded and had strengths in excess of 15,000 psi at 3500 F. Carbon additions to these and similar alloys had no significant effect on hot strength. Comparable additions of zirconium and hafnium to a Ta-1OW base showed zirconium was the more effective strengthener and was less detrimental to weld ductility. (Author)

Descriptors :   (*TANTALUM ALLOYS, CASE HARDENING), CARBON, OXYGEN, NITROGEN, TENSILE PROPERTIES, GRAIN STRUCTURES(METALLURGY), DUCTILITY, WELDABILITY, STRENGTH(PHYSIOLOGY), STRESSES, YTTRIUM, HEAT TREATMENT, OXIDES, HAFNIUM, ZIRCONIUM, CONTAMINATION, CRYSTALLIZATION, MICROSTRUCTURE, MANUFACTURING, MELTING, TENSILE PROPERTIES, IMPURITIES.

Subject Categories : Fabrication Metallurgy

Distribution Statement : APPROVED FOR PUBLIC RELEASE