PILOT PRODUCTION AND EVALUATION OF TANTALUM ALLOY SHEET.
Summary phase rept., part 2, 15 Feb 63-15 Apr 64,
WESTINGHOUSE ELECTRIC CORP PITTSBURGH PA ASTRONUCLEAR LAB
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Pilot quantities of T-222 Ta-9.6W-2.4Hf-0.01C sheet were produced from three-inch diameter ingots and evaluated. The T-222 alloy exhibited a significant improvement in elevated temperature mechanical properties over those of the solid solution alloy T-111 Ta8W-2Hf. The improvement in mechanical properties was achieved with little or no loss of fabricability or weldability. The effect of higher tungsten, hafnium, and carbon concentrations on the properties of T-222 were also investigated. Increasing the solute concentration of T-222 from 12 to 14 per cent at a W-Hf ratio of 41, with the standard 0.01 per cent carbon content, produced a slight improvement in the elevated temperature mechanical properties without adversely affecting fabricability or weldability. Increasing the carbon content of T-222 from 0.01 to 0.04 per cent did not produce any significant improvement in elevated temperature mechanical properties however, the weld-bend transition temperature was raised to above room temperature. Substitution of nitrogen for carbon in T-222 resulted in no gross change in mechanical or weld properties. An investigation of the effect of thermal and mechanical treatments demonstrated that T-222 was susceptible to aging response. The phases responsible were extracted and identified as complex carbides. Author