• Hamed, Ahmed
• Winther, Grethe
• El-Azab, Anter
• Rayaprolu, Sreekar

Abstract

The sensitivity of recrystallization kinetics in metals to theheterogeneity of microstructure and deformation history is a widelyaccepted experimental fact. However, most of the availablerecrystallization models employ either a mean field approach or usegrain-averaged parameters, and thus neglecting the mesoscopicheterogeneity induced by prior deformation. In the present study, weinvestigate the impact of deformation-induced dislocation (subgrain)structure on the kinetics of recrystallization in metals using thephase-field approach. The primary focus here is upon the role ofdislocation cell boundaries. The free energy formulation of thephase-field model accounts for the heterogeneity of the microstructureby assigning localized energy to the resulting dislocationmicrostructure realizations generated from experimental data. Thesemicrostructure realizations are created using the universal scaling lawsfor the spacing and the misorientation angles of both the geometricallynecessary and incidental dislocation boundaries. The resulting freeenergy is used into an Allen-Cahn based model of recrystallizationkinetics, which are solved using the finite element method.The solutions thus obtained shed light on the critical role of thespatial heterogeneity of deformation in the non-smooth growth ofrecrystallization nuclei and on the final grain structure. The resultsshowed that, in agreement with experiment, the morphology ofrecrystallization front exhibits protrusions and retrusions. Byresolving the subgrain structure, the presented algorithm paves the wayfor developing predictive kinetic models that fully account for thedeformed state of recrystallizing metals.

Topics

• impedance spectroscopy
• morphology
• polymer
• grain
• phase
• experiment
• simulation
• dislocation
• recrystallization
• grain growth