Accession Number : AD0769129

Title :   Dislocation Velocity Measurements in High Purity Niobium.

Descriptive Note : Technical rept.,

Corporate Author : ILLINOIS UNIV URBANA DEPT OF METALLURGY AND MINING ENGINEERING

Personal Author(s) : Walson,Robert P. ; Birnbaum,Howard K.

Report Date : OCT 1973

Pagination or Media Count : 140

Abstract : The velocity of screw dislocations on (211) planes, mixed dislocations on (101) planes, and mixed dislocations on (211) planes has been investigated microscopically in ultra-high purity niobium single crystals using Berg-Barrett X-ray topographs and chemical etching techniques. The Berg-Barrett X-ray topographic technique was found to be unsatisfactory for resolving individual dislocations or slip lines in the niobium used in this investigation. Chemical etching on the other hand produced satisfactory results and allowed the study of individual dislocations. An asymmetry of the velocity of screw dislocations on (211) planes was observed between a state of compression and a state of tension at room temperature. The screw and mixed dislocation velocities could be described by a power law dependence on stress. (Modified author abstract)

Descriptors :   (*Niobium, *Dislocations), Plastic deformation, Etching, Stresses, Low temperature, Single crystals, Velocity, Theses

Subject Categories : Metallurgy and Metallography
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE