Modeling of Dynamic Recrystallization Kinetics in Ce Containing Mg Alloys

Abstract

ZK60 alloys are known to have high mechanical strength relative to other Mg alloys. Composition variations in precipitate and solute content of ZK60 Mg alloys, with Zn variations and Ce substitutions, allow for the formation of higher melting point precipitates and impact dynamic recrystallization (DRX) behavior, microstructure, and mechanical properties. Creating constitutive models of the DRX process in various Mg alloys can help guide processing to efficiently create products with desirable microstructures. In this work, hot compression testing at various strain rates and temperatures was carried out. It has been shown that greater peak true stresses are required for DRX in alloys processed at lower temperatures and higher strain rates. Moreover, increases in Zn and Ce content increase the stress that the microstructure can absorb before DRX starts. Finally, electron backscattered diffraction mapping shows how texture is decreased by DRX compared to the as-received conditions and how DRX was more advanced for low Zr and low strain rate conditions, consistently with the developed model. Based on these experimental results, a constitutive model to quantify the relationship between the Zener–Hollomon parameter and peak stress was developed. The model was shown to reflect the experimentally obtained results accurately.