Beta decomposition of (Hf/sub x/Zr/sub 1-x/)/sub 80/Nb/sub 20/ ternary alloys
- Sandia Labs., Albuquerque, NM
The processes of beta decomposition have been examined in ternary alloys of the form (Hf/sub x/Zr/sub 1-x/)/sub 80/Nb/sub 20/ to determine the influence of Hf additions to a basic Zr/sub 80/Nb/sub 20/ composition. In the chill cast condition, Hf additions have been found to decrease the temperature coefficient of electrical resistivity from a value of -0.0015%/K for the binary Zr/sub 80/Nb/sub 20/ alloy to a value of -0.011%/K for a (Hf/sub 50/Zr/sub 50/)/sub 80/Nb/sub 20/ ternary alloy. This change is explained in terms of the bcc lattice instability typical of Ti, Zr, and Hf alloys. The Hf additions enhance the kinetics of omega-phase precipitation during aging at 648 K. The aging of a (Hf/sub 05/Zr/sub 95/)/sub 80/Nb/sub 20/ alloy for 12 h results in the precipitation of a high volume fraction of cuboidal shaped omega-phase particles. A phase separation which results in the formation of solute lean discs (..beta../sub l/) occurs together with the precipitation of the omega-phase. These discs formed both randomly within the matrix and heterogeneously along dislocations and at grain boundaries.
- OSTI ID:
- 6428267
- Journal Information:
- Metall. Trans., A; (United States), Journal Name: Metall. Trans., A; (United States) Vol. 9:8; ISSN MTTAB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360102* -- Metals & Alloys-- Structure & Phase Studies
AGING
ALLOYS
CASTING
CRYSTAL-PHASE TRANSFORMATIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
FABRICATION
HAFNIUM
HAFNIUM ADDITIONS
HAFNIUM ALLOYS
LATTICE PARAMETERS
METALLURGICAL EFFECTS
METALS
NIOBIUM ALLOYS
NUCLEATION
PHASE STABILITY
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PRECIPITATION
REFRACTORY METALS
SEPARATION PROCESSES
STABILITY
TRANSITION ELEMENTS
ZIRCONIUM ALLOYS
ZIRCONIUM BASE ALLOYS