PROCESS DEVELOPMENT AND EVALUATION OF PROPERTIES OF F-48 NIOBIUM ALLOY. Final Report
The reproducibility of mechanical properties of the F-48 niobium alloy when the material is fabricated by warm extruding arc-melted ingots (both 2.8: 1 and 5: 1 extrusion ratios were used) and rolling to effect overall reductions on the order of 80 to 90% was evaluated. The rolled material was then heat treated for 1 hr at either 2525 deg F (reduced 80%) or 2400 deg F (reduced 90%), resulting in structures that were nominally 20% recrystallized. Generally, however, the material retained considerable structural attributes from the as- cast ingots. Ductile-to-brittle transition temperatures, either under slow- loading tensile testing or rapid impact conditions, were substantially above room temperature. Some tensile ductility was usually retained at room temperature. At temperatures above the transition-temperature region, tensile properties were consistent and reproducible. Material chemistry from heat-to-heat was consistent and reproducible. Creep strength at high temperatures (2200 and 2500 deg F) was erratic and far less reproducible without closer control of fabrication operations than was tensile strength. Creep strength sometimes varied from surface to central layers of rolled plate. With close process control, heavy plate of F-48 having both good room-temperature ductility and a 1% 10-hr creep strength at 2200 deg F of 15,000 psi could be produced. For the heats of F-48 evaluated, design to greater than 9000 psi for a 10-hr 1% creep life at 2200 deg F, or greater than 8500 psi for a total deformation of 1% in 10 hr at 2200 deg F would involve risk. (auth)
- Research Organization:
- Battelle Memorial Inst., Columbus, Ohio
- DOE Contract Number:
- W-7405-ENG-92
- NSA Number:
- NSA-17-032567
- OSTI ID:
- 4660711
- Report Number(s):
- BMI-X-249
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CONFIGURATION
CONTROL
CREEP
DUCTILITY
EXTRUSION
FABRICATION
HEAT RESISTING METALS
HEAT TREATMENTS
HIGH TEMPERATURE
HOT WORKING
MECHANICAL PROPERTIES
METALS, CERAMICS, AND OTHER MATERIALS
MOLYBDENUM ALLOYS
NIOBIUM ALLOYS
RECRYSTALLIZATION
REPORT
ROLLING
STABILITY
TENSILE PROPERTIES
TESTING
TUNGSTEN ALLOYS
ZIRCONIUM ALLOYS