Accession Number : AD0804929

Title :   DUCTILE-BRITTLE TRANSITION IN REFRACTORY METALS.

Descriptive Note : Summary rept. 1 Sep 65-31 Aug 66,

Corporate Author : RUTGERS - THE STATE UNIV NEW BRUNSWICK NJ

Personal Author(s) : Weissmann, S. ; Ellis, T.

Report Date : OCT 1966

Pagination or Media Count : 20

Abstract : Zone-refined tungsten crystals were compressed at 298 K up to a residual strain of 0.45% and at 77 K up to a residual strain of 0.35%. Compression at 298 K resulted in the formation of a plastically deformed surface layer which confined the bulk of the elastic strains in the crystal and which was released when the surface layer was removed by etching. By contrast, compression at 77 K gave rise to the generation of dislocations, which were distributed throughout the crystal and which were predominantly confined to sites of ingrown dislocations. The lattice of the subgrains appeared to become elastically strained and not plastically deformed by slip dislocations. With increased compression a preferred directionality of the maximum normal elastic strain parallel to the 100 plane began to develop, which is interpreted as an indication for the tendency of the crystal to cleave.

Descriptors :   *TUNGSTEN), (*DUCTILE BRITTLE TRANSITION, SINGLE CRYSTALS, CRYSTAL STRUCTURE, COMPRESSIVE PROPERTIES, STRAIN(MECHANICS), CRYSTAL DEFECTS, DEFORMATION, TEMPERATURE, CRYSTAL LATTICES, ZONE MELTING, PURIFICATION.

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE