Accession Number : AD0487751

Title :   RESEARCH FOR SOLUBILITY OF INTERSTITIALS IN COLUMBIUM. PART III. A STUDY OF COLUMBIUM-RICH ALLOYS IN THE TERNARY SYSTEMS CB-MO-O, CB-MO-N AND CB-MO-C.

Descriptive Note : Final technical rept. 15 Apr 65-1 Apr 66,

Corporate Author : WESTINGHOUSE RESEARCH LABS PITTSBURGH PA

Personal Author(s) : Taylor, A.

Report Date : JUN 1966

Pagination or Media Count : 85

Abstract : Using a dynamic leak method and a Sieverts apparatus, combined with X-ray diffraction, micrographic and thermal techniques, the solubilities of oxygen, nitrogen and carbon have been determined in columbium and in columbium-rich columbium-molybdenum alloys. At oxygen pressures above 10 to the minus 14th power torr, Cb is in thermodynamic equilibrium with oxide vapor and takes up to 6 at. % O2 into solid solution at 1775 and 4.7(5) at. % O2 at 1500 C. This falls steadily with Mo additions, the amount of O2 in solid solution at 1500 C dropping to 1.7(5) at. % in an alloy containing 10% Mo. The addition of Mo to Cb drastically reduces the amount of N2 which can be retained in solid solution. At 2200 C, the N2 maximum content drops from about 14.5 at % N2 at pure Cb to almost zero at 10 at. % Mo. In the case of carbon, the amount which can be retained in solution in Cb is less than 0.5 at. % at 2000 C, and is little changed with added Mo. Up to about 48 at. % Mo, and with C greater than 0.5 at. %, the phase in equilibrium with the (Cb, Mo) primary solid solution is Cb2C. (Author)

Descriptors :   (*NIOBIUM, SOLUBILITY), (*NIOBIUM ALLOYS, ADDITIVES), MOLYBDENUM ALLOYS, CHEMICAL EQUILIBRIUM, THERMODYNAMICS, OXYGEN, NITROGEN, CARBON, PHASE STUDIES, CRYSTAL LATTICES, PRESSURE, TEMPERATURE.

Subject Categories : Physical Chemistry
      Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE