On the Theory of Microstructure Changes in Metals: Hardening, Recovery, Grain Boundary Motion, and Recrystallization

Continuum based Model of Inhomogeneous Hardening and Recovery as a Precursor for the Formation of Recrystallization Nuclei

Ausgabe: kartoniert
ISBN: 978-3-85125-172-2
Umfang: 156 Seiten
Sprache: Englisch
Erschienen: Dezember 2011
Reihe: Monographic Series TU Graz / Advanced Materials Science, Band Vol. 1a

Vergriffen!

Hardening and simultaneously running recovery during and after a deformation are characterized by the dislocation density and the concentration of the point defects (vacancies and interstitials). The change rates of these magnitudes hitherto were calculated using differential equations with the time as the unique independent variable. Therewith these processes only can be described for homogeneous deformation. For generation of recrystallization nuclei, gradients of migration energy of the point defects as a consequence of strain energy and / or rotation gradients are necessary, which only occur with inhomogeneous deformation. Therefore a space dependent deformation rate was introduced to the acquainted simultaneous rate equations of the dislocation density and of the point defects. Taking into consideration all essential structural parameters a detailed and realistic model results suited for calculation of the progress of dislocation density and concentration of the point defects in space and time. From the development of the dislocation density different levels of strain energy can be recognized, which are the precondition for recrystallization nucleation. As in these regions also high gradients of rotation occur, recrystallization nuclei can arise there.

Hardening and simultaneously running recovery during and after a deformation are characterized by the dislocation density and the concentration of the point defects (vacancies and interstitials). The change rates of these magnitudes hitherto were calculated using differential equations with the time as the unique independent variable. Therewith these processes only can be described for homogeneous deformation. For generation of recrystallization nuclei, gradients of migration energy of the point defects as a consequence of strain energy and / or rotation gradients are necessary, which only occur with inhomogeneous deformation. Therefore a space dependent deformation rate was introduced to the acquainted simultaneous rate equations of the dislocation density and of the point defects. Taking into consideration all essential structural parameters a detailed and realistic model results suited for calculation of the progress of dislocation density and concentration of the point defects in space and time. From the development of the dislocation density different levels of strain energy can be recognized, which are the precondition for recrystallization nucleation. As in these regions also high gradients of rotation occur, recrystallization nuclei can arise there.