LOW-TEMPERATURE BRITTLENESS OF REFRACTORY METALS. Annual Summary Report No. II for July 31, 1959 to July 31, 1960

Technical Report · Mon Aug 01 04:00:00 EDT 1960

OSTI ID:4141920

Schadler, H W; Low, Jr, J R

The recrystallization characteristics of cold-rolled tungsten single crystals produced by electron-bombardment floating-zone refintng were studied. Tungsten single crystals of various orientations were rolled 44, 70, 76, and 85% reduction in area at 450 and 400 deg C and annealed at 600 to 1600 deg C. Hardness of each specimen and the effect of annealing temperature on the grain size of the recrystallized material were determined. Procedures for producing polycrystalline tungsten are contained. Studies on the fracture characteristics of polycrystalline tungsten revealed that grain boundaries are important to the initiation of fracture, even in high-purity tungsten, that twinning is a factor in the propagation of brittle cracks, and that twins may inttiate brittle fracture. Attempts to measure the stress and temperature dependence of dislocation velocities in high-purity tungsten single crystals were not successful because all of the dislocations present in the crystal moved under the applied stress. The strain-rate sensitivity of tungsten single crystals was measured at 298 and 77 deg K for strains of 1 to 10%. The strain-rate sensitivity at 77 deg K is 60% of that at 298 deg K. (C.J.G.)

• Research Organization: General Electric Co. Research Lab., Schenectady, N.Y.
• NSA Number: NSA-14-025925
• OSTI ID: 4141920
• Report Number(s): 60-GC-124
• Country of Publication: United States
• Language: English

Related Subjects

ANNEALING
BRITTLENESS
COLD WORKING
CRACKS
DEFECTS
DEFORMATION
DISLOCATIONS
ELECTRON BEAMS
FAILURES
GRAIN BOUNDARIES
GRAIN SIZE
HARDNESS
LOW TEMPERATURE
METALS
METALS, CERAMICS, AND OTHER MATERIALS
MONOCRYSTALS
RECRYSTALLIZATION
REFINING
REFRACTORY METALS
REPORT
ROLLING
SENSITIVITY
STRESSES
TEMPERATURE
TUNGSTEN
TWINNING
ZONES