DAMPING IN DEFORMED IRON CONTAINING INTERSTITIAL IMPURITIES.
COLUMBIA UNIV NEW YORK HENRY KRUMB SCHOOL OF MINES
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The internal friction spectrum in polycrystalline iron has been studied around 1 Hz from -60 degrees C to 380 degrees C as a function of deformation, interstitial content, state of annealing, strain amplitude and the temperature at which the recrystallization is carried out prior to deformation. Plastic deformation produces two major peaks centered at 47 degrees C peak D and at temperature range between 220 degrees C to 290 degrees C cold-work peak. The features of peak D are explained by a model based on enhanced Snoek relaxation, with strong harmonic generation, caused by the motion of the dislocations. In a dilute iron-carbon alloy the cold-work peak initially rises and then falls with increasing deformation. The peak temperature in the same specimen drops with increasing deformation. In the iron-carbon system Schoecks theory based on dislocation motion giving rise to the anelastic strain can explain the observed features of the cold-work peak. The rising background damping occurring at the higher temperature side near the cold-work peak is observed to be sensitive to the degree of deformation, amount of solute content and the state of annealing. Author
- Metallurgy and Metallography