HIGH-TEMPERATURE MATERIALS PROGRAM PROGRESS REPORT No. 23, PART A

Technical Report · Fri May 31 00:00:00 EDT 1963

OSTI ID:4712324

Stress-rupture tests comparing sintered and arc-cast molybdenum at 2200 deg C furnished additional evidence that the Mo- A material is a powder- metallurgy-sintered product and that Mo- B and Mo--C are arc-cast materials. The stress-rupture life and ductility of arc-cast molybdenum were found to be similar, whereas the sintered material differs from the arc-cast material and its strength and creep characteristics are dependent on the source. The sintered molybdenum is susceptible to contamination by trace impurities in an inert atmosphere. By comparison, the arc-cast material was extremely clean. The stressrupture and creep testing of tungsten was initiated. Tests were performed at 1600 to 2800 deg C for rupture times to 12 hours. The test results indicate that the strength and creep characteristics of the material are dependent on the source. The stress-rupture testing of tantalum was continued with the emphasis on the effect of contaminants in the test atmosphere. As expected, the stress- rupture tests confirmed that this material is much more susceptible to contamination at temperatures of 2400 to 2600 deg C than the other refractory materials tested. Consistent results were obtained in an argon atmosphere using a tantalum foil around the specimen. Prior tests without this protective foil produced unusually scattered results. The preliminary screening of brazing alloys for tantalum was completed. The major evaluation was performed on braze alloys from the Nb--Ta--V ternary system. The advantages of alloys from this system are: suitable for brazing temperatures between 1950 and 2400 deg C; no intermediate phases are present in the alloys or in the diffision products formed by the alloys; erosion of the base metal from the liquid braze alloys is considered minimal for this time exposure, ranging from 0 to 0.005 inch during the braze cycle; increase in remelt temperature of the braze joint by diffusion is comparatively rapid; and the alloys can be applied to the braze joint by standard sheet, wire, and powder techniques. Effects of radiation of high- temperature alloys. Two creep-rupture test stands used in the hightemperature alloy program were modified and are now being used to test the refractory metals in a hydrogen atmosphere. Two creep-rupture stands remain at Ge-ITS and will be used for testing the control and irradiated high-temperature alloy specimens. Tungsten specimens were irradiated in the Oak Ridge Research Reactor at reactor ambient temperatures. A set of 116 tungsten wires was also irradiated. Tungsten creep-rupture control specimens were tested at 1100 to 1400 deg C. Irradiated creep-rupture specimens were tested at the same temperatures. Creep-rupture testing of control specimens containing trace quantities of boron were initiated at GE-ITS. Capsule 33MT-99 containing the irradiated, boron-containing specimens was removed from the ETR following a two-cycle irradiation. A satisfactory standard procedure for preparing irradiated and control Rene 41 specimens for electron micrography was developed, and the structure evaluation of this material was resumed. (auth)

• Research Organization: General electric Co. Advanced Technology Services, Cincinnati
• DOE Contract Number: AT(40-1)-2847
• NSA Number: NSA-17-029320
• OSTI ID: 4712324
• Report Number(s): GEMP-23A
• Resource Relation: Other Information: Orig. Receipt Date: 31-DEC-63
• Country of Publication: United States
• Language: English

Related Subjects

METALS, CERAMICS, AND OTHER MATERIALS
ALLOYS
ARGON
BRAZING
CASTING
COATING
CONTROL
CREEP
DIFFUSION
DUCTILITY
ELECTRIC ARCS
EROSION
ETR
FAILURES
FUEL CANS
HEAT RESISTING ALLOYS
HEAT RESISTING METALS
HIGH TEMPERATURE
HYDROGEN
IMPURITIES
INERT GASES
IRRADIATION
JOINTS
LIQUID METALS
MATERIALS TESTING
MELTING
MOLYBDENUM
NIOBIUM ALLOYS
ORR
PHASE DIAGRAMS
POWDER METALLURGY
POWDERS
RADIATION EFFECTS
REFRACTORIES
RESEARCH REACTORS
SAMPLING
SHEETS
SINTERED MATERIALS
STANDARDS
STRESSES
TANTALUM
TANTALUM ALLOYS
TENSILE PROPERTIES
TUNGSTEN
VANADIUM ALLOYS
WIRES