Evaluation of Hot Deformation and Dynamic Recrystallization Behaviors of Advanced Reduced-Activated Alloy (ARAA)
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The hot deformation behavior of advanced reduced-activation alloy (ARAA) was investigated using hot torsion tests. The flow stress decreased as deformation temperature increased and as strain rate decreased. The flow behavior demonstrated the typical dynamic recrystallization (DRX). Based on the constitutive analysis of peak stress, the activation energy for hot deformation was found to be 330.3 kJ mol−1. Peak stress was analyzed as a function of the Zener–Hollomon parameter, and calculated and experimental values were in good agreement. A DRX kinetic model for ARAA was derived with deformation conditions based on the Avrami-type model. It was confirmed that the volume fraction of dynamically recrystallized grains increased as deformation temperature increased and as strain rate decreased. The necklace structure and grain boundary bulging were observed in the deformed microstructure of ARAA. The suggested DRX mechanism for ARAA during hot working is discontinuous DRX.
KeywordsRAFM steel Hot deformation Flow behavior Dynamic recrystallization Constitutive analysis
This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Republic of Korea (No. 2017R1A2B4010034).
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