THE ANNEALING BEHAVIOR OF COLD-ROLLED NIOBIUM (thesis)
The recrystallization behavior of niobium is in agreement with chassical recrystallization theory in that recrystallization is promoted by increasing annealing temperature, increasing annealing time, and increasing prior deformation.'' Drawings are presented which show, semi-quantitatively, the relative effects of annealing time, annealing temperature, and prior deformation on the initiation and termination of recrystallization. Graphs showing the effects of one-hour anneals on the room temperature tensile properties of cold- rolled niobium are presented. Although otherwise inconclusive, hardness data are presented which indicate that minor degrees of contamination have a marked effect on the hardness of niobium and that hardness is, therefore, a poor criterion for determining recrystallization in niobium. Photomicrographs showing 80% cold- rolled powder-metallurgy and arc-cast niobium after one-hour anneals at room temperature (no anneal), 900, 1000, 1100, and 1200 deg C, and after fifteen- minute, two-hour, and ten-hour anneals at 1000 and 1100 deg C are presented. These show the recrystallizing powder-metallurgy niobium to have a finer grain size than the recrystallizing arc-cast niobium after identical treatment. Other than the recrystallized grain size, no significant differences were noted in the annealing behavior of arc-cast and powder-metallurgy niobium. The room temperature tensile properties of the two materials also exhibit no significant differences. (auth)
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- W-7405-ENG-26
- NSA Number:
- NSA-13-000762
- OSTI ID:
- 4331744
- Report Number(s):
- ORNL-2372
- Resource Relation:
- Other Information: Submitted to the Univ. of Tennessee. Orig. Receipt Date: 31-DEC-59
- Country of Publication:
- United States
- Language:
- English
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