THE INTERSTITIAL-DISLOCATION DAMPING INTERACTIONS IN COLUMBIUM
A study of niobium was undertaken to determine if coldwork peaks were found in other bcc metals beside iron, and if found, to study their characteristics, and determine a model for the peak. Cold-work peaks were found in niobium-- nitrogen (also tantalum-- nitrogen) alloys. The characteristics of the peak were found to be divided into two parts; a low nitrogen (LN) part, below 0.018%, and a high nitrogen (HN) part above. For the LN peak the height was a linear function of initial nitrogen content while only slightly dependent upon the amount of deformation up to 5%. The characteristics of the HN peak were relatively insensitive to both nitrogen content and deformation. A model is presented which explains the observed characteristics of the cold-work peaks. The relaxation is pictured as occurring in clusters of interstitials around the dislocations. The clusters can interact with an externally applied stress by changing shape or orientation. The high relaxation strength is the result of the interaction of the interstitials in the clusters and the increase in relaxation time is the result of the cluster's increase in size. The HN peak model is identical with that proposed for the LN peak; its characteristics determined by the nitrogen content of the solubility limit at approximately the peak temperature. Nitrogen contents in excess of this amount forms precipitates which have no effect upon the relaxation.
- Research Organization:
- Univ. of Illinois, Urbana
- NSA Number:
- NSA-16-033491
- OSTI ID:
- 4804348
- Journal Information:
- Dissertation Abstr., Journal Name: Dissertation Abstr. Vol. Vol: 23
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Related Subjects
CONFIGURATION
DEFECTS
DEFORMATION
DISLOCATIONS
FRICTION
INTERSTITIALS
IRON
LATTICES
METALS
METALS, CERAMICS, AND OTHER MATERIALS
NIOBIUM
NIOBIUM NITRIDES
NITROGEN
PRECIPITATION
QUANTITATIVE ANALYSIS
SOLID CLUSTERS
SOLUBILITY
STRESSES
TANTALUM NITRIDES
TEMPERATURE
TENSILE PROPERTIES
THICKNESS