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Continuous dynamic recrystallization (CDRX) model for aluminum alloys

Maizza, Giovanni, Pero, Renato, Richetta, Maria, Montanari, Roberto
Journal of materials science 2018 v.53 no.6 pp. 4563-4573
alloys, aluminum, crystallization, deformation, engineering, manufacturing, mathematical models, mechanical properties, microstructure, pressing, temperature
The control of a microstructure, during and after hot forming, is crucial to tailor optimum mechanical properties for specific applications. Recrystallization is a key process which may contribute to a great extent to microstructure development. Dynamic recrystallization is becoming an attracting research area to investigate novel hot forming routes in order to maximize the performance of aluminum products while shortening the time required for manufacturing. A continuous dynamic recrystallization (CDRX) mathematical model was developed by Gourdet–Montheillet (GM) to predict the inherent phenomena of an AA1200 alloy. In the present work, the original GM model has been extended and applied to study CDRX in a 5052 aluminum alloy. The proposed model embodies a solid solution and second phase strengthening, through newly estimated kinetic factors and a kinetic constant, respectively, to discern the CDRX behavior of 5052 aluminum alloy compared to AA1200. The latter kinetic constant relies on the Kocks–Mecking–Estrin (KME) theory. The input law of the fraction of high angle boundaries (f HAB), as a function of strain (ε) (but independent of temperature and strain rate), is defined as the best fitting function of the experimental data. The results are presented in terms of stress–strain curves, dislocation density, and (sub) grain size, as these are important design parameters from an industrial and engineering viewpoint. The model has been validated successfully, from both a qualitative and quantitative point of view, against various literature data sources and tests (e.g., hot compression, hot plane strain compression, and equal channel angular pressing) pertaining to the 5052 alloy and other similar Al–Mg alloys.