PROPERTIES OF YTTRIUM AND THE RARE EARTH METALS OXYGEN AND ALLOY SYSTEMS. OXYGEN AND ALLOY SYSTEMS

Technical Report · Mon Feb 20 04:00:00 EST 1961

OSTI ID:4821955

Love, B

Partial constitutional diagrams were established for a number of systems containing yttrium and the lanthanide elements. Alpha yttrium and erbium are completely soluble in all proportions. The yttrium --neodymiuin system is more complex. There is partial solubility at both ends of the system. An intermediate phase is present at the equiatomic percentage composition. No marked beta phase stabilization was established. The rare earth rich end of the yttrium, erbium, neodymium, and samarium systems with oxygen were investigated. The solubility of oxygen is low in the metals at temperatures up to the transformation temperature or 1000 deg C. The transformation temperature of neodymium is essentially unaffected, that of samarium is raised slightly. The nature of the elevated temperature portion of each system is less certain and two alternative phase diagrams are proposed. The preferred diagram indicates the presence of a hign temperature interstitial monoxide. The cobalt end of the cobalt --erbium system was investigated. A number of intermetallic compounds are formed. The first of these, Co/sub 17/Er/sub 2/, enters into eutectic reaction with cobalt. The solubility of erbium in cobalt is low, and the cobalt phase transformation is essentially unaffected by the presence of small additions of erbium. The cobalt--yttrium system appears to be similar. Tantalum -- lanthanum, tantalum --erbium, tantalum -ytterium, niobium --erbium, and niobium -- yttrium systems were investigated. All systems were similar in their general characteristics. An extensive liquid immiscibility region is present which terminates in a monotectic very near the tantalum (niobium) end of the system. A eutectic is present at the rare earth end of the system. Room temperature solid solubility is very low, but there may be slight solubility at elevated temperature. The alpha to beta transformation temperature was determined to be 848 deg C for neodymium and 93O deg C for samarium. The transformation temperature of yttrium is approximately 20 to 3O deg C below the melting point of yttrium. Both the transformation and melting temperatures are somewhat dependent upon metal purity. Atmospheric corrosion rates were determined in the above systems. Lower rates were found for certain niobium alloys, and for cobalt compositions, with added rare earths. Improved mechanical properties were found for yttrium --erbium alloys and for yttrium -zirconium alloys ascribed to solid solution hardening. The latter age at room temperature and rapidly overage at elevated temperatures. Procedures for purification of yttrium and erbium by vacuum distillation were developed. Improved methods for oxygen and tantalum analysis are described. The addition of erbium to beryllium yields alloys with improved purity and grain refinement. (auth)

• Research Organization: Research Chemicals. Div. of Nuclear Corp. of America, Burbank, Calif.
• NSA Number: NSA-16-005315
• OSTI ID: 4821955
• Report Number(s): WADD-TR-61-123
• Country of Publication: United States
• Language: English

Related Subjects

ALLOTROPY
ALLOYS
BERYLLIUM ALLOYS
CHEMICAL REACTIONS
CHEMISTRY
COBALT ALLOYS
CORROSION
DISTILLATION
EFFICIENCY
ERBIUM
ERBIUM ALLOYS
ERBIUM OXIDES
EUTECTICS
GRAIN SIZE
HEAT TREATMENTS
HIGH TEMPERATURE
IMPURITIES
INTERMETALLIC COMPOUNDS
LANTHANUM ALLOYS
MECHANICAL PROPERTIES
MELTING POINTS
METALS
NEODYMIUM
NEODYMIUM ALLOYS
NEODYMIUM OXIDES
NIOBIUM ALLOYS
OXIDES
OXYGEN
PHASE DIAGRAMS
QUALITATIVE ANALYSIS
QUANTITATIVE ANALYSIS
RARE EARTHS
REFINING
SAMARIUM
SAMARIUM OXIDES
SOLID SOLUTIONS
SOLUBILITY
TANTALUM
TANTALUM ALLOYS
VACUUM
YTTERBIUM ALLOYS
YTTRIUM
YTTRIUM ALLOYS
YTTRIUM OXIDES
ZIRCONIUM ALLOYS