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Interaction of carbon with dislocations in tungsten.

Gray, R. J. (1970) Interaction of carbon with dislocations in tungsten. Doctoral thesis, University of Surrey (United Kingdom)..

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Abstract

The interaction of carbon atoms with dislocations in tungsten has been investigated using the techniques of tensile testing and low frequency internal friction. The investigation involved the study of strain-ageing, the carbon Snoek peak and a previously reported "cold-work peak". It has been shown that at temperatures above 550°C, carbon in quenched tungsten causes strain-ageing the rate of which may be expressed in terms of the kinetics of Cottrell and Bilby. The apparent activation energy of yield point return (63 +/- 3 kcal/mole) is considerably higher than that for carbon diffusion (43 +/- 2 kcal/mole) estimated from the position of the Snoek peak. This apparent discrepancy is explained either by the interaction of diffusing carbon atoms, or by the dissolution of carbides during the strain-ageing process. A quantitative model has been proposed to account for the latter possibility. The observed deviation from Cottrell-Bilby kinetics during the early stages of strain ageing of carbon doped, slowly-cooled tungsten has been attributed to the occurrence of dislocation recovery preceding the pinning of dislocations. An internal friction peak observed at temperatures between 550° and 600°C during the heating of cold-worked tungsten containing carbon has been shown not to be a relaxation peak, it is accounted for in terms of the change in the rate of recovery of temperature-dependent dislocation damping as carbon atoms become mobile during the heating cycle.

Item Type: Thesis (Doctoral)
Divisions : Theses
Authors :
NameEmailORCID
Gray, R. J.UNSPECIFIEDUNSPECIFIED
Date : 1970
Contributors :
ContributionNameEmailORCID
http://www.loc.gov/loc.terms/relators/THSUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Depositing User : EPrints Services
Date Deposited : 09 Nov 2017 12:17
Last Modified : 09 Nov 2017 14:47
URI: http://epubs.surrey.ac.uk/id/eprint/844357

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