DUCTILE-BRITTLE TRANSITION IN THE REFRACTORY METALS
>Ductile-brittle transition behavior occurs in the bodycentered cubic refractory metals niobium, molybdenum. tungsten, and chromium. The available data for vanadium suggest that brittleness at low temperatures is attributable a low-stress-rate hydogen embrittlement. However, the occurrence of ductile- brittle transition behavior is not precluded. No brittle transition has yet been found in tantalum. Trsnsition temperature can be greatly influenced by testing and material conditions. As a general rule, the following fators increase the temerature at which the brittle transition occurs: recrystallization, decreasing amounts of cold work, increasing grain size, increasing interstitial content, increasing strain rate, and introduction of triaxial stresses. The transition from ductile to brittle behaavior is associated with a rapid rise in yield strength occurring with reductions in temperature. Brittle behavior is observed to occur when the yield strength equals the fracture strength. Cottrell's theory of dislocation locking by interstitial atoms is generally used a explain the yield-strength rise at low temperatures. (auth) l6204 A high intensity ion beam moving in a magnetic field has been investigatad as a means of effecting closure on Hanford type fuel elements. The investigation was successful in producing a high speed process, but the weld results were not consistent with present fuel element specifications. Other disadvantages were silicon contamination in the weld metal, poor electrode life, and difficulty in controlling the weld width. (auth)
- Research Organization:
- Battelle Memorial Inst., Defense Metals Information Center, Columbus, Ohio
- NSA Number:
- NSA-13-016203
- OSTI ID:
- 4253559
- Report Number(s):
- DMIC-114; AD-216526; PB-151070
- Country of Publication:
- United States
- Language:
- English
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The brittle-to-ductile transition in germanium
HEAT RESISTANT MATERIALS. CHROMIUM-BRITTLE OR DUCTILE
Related Subjects
BRITTLENESS
CHROMIUM
COLD WORKING
COTTRELL THEORY
DEFECTS
DEFORMATION
DISLOCATIONS
DUCTILITY
FAILURES
GRAIN SIZE
HYDROGEN
INTERSTITIALS
LATTICES
MATERIALS TESTING
METALLURGY AND CERAMICS
MOLYBDENUM
NIOBIUM
RECRYSTALLIZATION
REFRACTORIES
STRESSES
TANTALUM
TEMPERATURE
TENSILE PROPERTIES
TUNGSTEN
VANADIUM