SUBSTRUCTURE AND MECHANICAL PROPERTIES OF REFRACTORY METALS

Technical Report · Mon Apr 01 04:00:00 EST 1963

OSTI ID:4669802

Lement, B S; Thomas, D A; Weissmann, S; Owen, W S; Hirsch, P B

Coordinated program on W, Mo, Ta, and Nb was carried out by means of advanced microscopic, x-ray-diffraction, and mechanical testing techniques. The effective surface energy for fracture of molybdenum strip was found to be about 3000 ergs/cm/sup 2/. The tensile ductility transition in molybdenum is associated with the occurrence of necking. Fibering in tungsten involves formation of ribbon-like grains containing a dislocation cell structure in which fine platelets occur. Discontinuous yielding in tantalum single crystals is correlated with a decrease in the shearing strain in the principal slip system to zero while that in the secondary system continues to increase. The binding energy between oxygen atoms and dislocations in tantalum is about 0.54 ev. Dissociation of screw dislocations along three interesting symmetrically located planes may account for the strong lattice friction stress in bcc metals. (auth)

• Research Organization: ManLabs, Inc., Cambridge, Mass.
• NSA Number: NSA-17-032565
• OSTI ID: 4669802
• Report Number(s): ASD-TR-61-181(Pt.III)
• Country of Publication: United States
• Language: English

Related Subjects

ATOMS
CONFIGURATION
DEFECTS
DIFFRACTION
DUCTILITY
FAILURES
FIBERS
LATTICES
MECHANICAL PROPERTIES
METALLOGRAPHY
METALS
METALS, CERAMICS, AND OTHER MATERIALS
MOLYBDENUM
MONOCRYSTALS
NIOBIUM
OXYGEN
STRESSES
TANTALUM
TENSILE PROPERTIES
TESTING
TUNGSTEN
X RADIATION