Accession Number : AD0612194

Title :   DISLOCATION STRUCTURE OBSERVATIONS AT LUDERS FRONTS IN TANTALUM,

Corporate Author : STANFORD UNIV CALIF DEPT OF MATERIALS SCIENCE

Personal Author(s) : Barbee,Troy W. ,Jr. ; Huggins,Robert A.

Report Date : JAN 1965

Pagination or Media Count : 27

Abstract : Dislocation configurations at Luders fronts in tantalum which deformed by non-uniform discontinuous yielding have been examined. No contrast structure was observed in grain boundaries of recrystallized material unless evidence of sample mishandling or incomplete recrystallization was observed. No classical pileups were seen although slip bands were found in regions just ahead of a Luders band. Dislocation source action at or near grain boundaries was observed at Luders fronts and within Luders bands. The dislocation density was observed to increase during the passage of a Luders front and grain boundaries were seen to rapidly develop contrast structure during the passage of a Luders front. These observations are discussed in light of current knowledge concerning the mechanism of discontinuous yielding. (Author)

Descriptors :   (*METALLOGRAPHY, TANTALUM), (*TANTALUM, CRYSTAL DEFECTS), (*CRYSTAL DEFECTS, TANTALUM), DEFORMATION, SURFACE PROPERTIES, GRAIN BOUNDARIES, DENSITY, ELECTRON MICROSCOPY, FOILS(MATERIALS)

Distribution Statement : APPROVED FOR PUBLIC RELEASE