Open PhD position: Modeling of continuous dynamic recrystallisation (CDRX)

One of the European Union’s objectives in climate change consists of reaching net-zero greenhouse gas emissions by 2050. Such per- spective puts the metallic materials industry, as a large contribu- tor to carbon emissions, under tremendous pressure for change and requires the existence of robust computational materials strate- gies to enhance and design, with a very high confidence degree, new metallic materials technologies with a limited environmental impact. From a more general perspective, the in-use properties and durability of metallic materials are strongly related to their microstructures, which are themselves inherited from the thermo- mechanical treatments.
Hence, understanding and predicting microstructure evolutions are nowadays a key to the competitiveness of industrial companies, with direct economic and societal benefits in all major economic sectors (aerospace, nuclear, renewable energy, and automotive in- dustry).
Multiscale materials modeling, and more precisely simulations at the mesoscopic scale, constitute the most promising numeri- cal framework for the next decades of industrial simulations as it compromises between the versatility and robustness of physically- based models, computation times, and accuracy. The digimu con- sortium is dedicated to this topic at the service of major industrial companies.
In this context, the efficient and robust modeling of evolving in- terfaces like grain boundary networks is an active research topic, and numerous numerical frameworks exist. In the context of hot metal forming and when large deformation of the calculation do- main and the subsequent migration of grain boundary interfaces are involved, a new promising, in terms of computational cost, 2D front tracking method called ToRealMotion algorithms [1,2] was recently developed.
This PhD will be firstly dedicated to the extension of existing nu- merical framework dedicated to the modeling of discontinuous dy- namic recrystallization where recovery is not a predominant mech- anism to the context of CDRX where progressive evolution of sub- grain interfaces (low misorientation) into grain boundaries (high misorientation) by dislocation accumulation, annihilation and re- arrangement must be considered. Pre-existing developments [3] in context of a level-set full-field formulation will be improved and this mechanism will also be integrated to the ToRealMotion front-tracking algorithms.
The developments will be tested/optimized for pre-existing exper- imental data concerning two aluminum grades and one zirconium alloy. Concerning Al grades, the first one (6016 Al alloy) is of great interest for Constellium in automotive applications and the second one (7010 Al alloy) is of great interest for Aubert&Duval Issoire in aeronautic applications. Finally, Zircaloy-4, used mainly by Framatome in nuclear cladding applications, will also be considered.
The developments will be integrated in the DIGIMU® software.

References:
[1] S. Florez, K. Alvarado, and M. Bernacki. Modelling and Simulation in Materials Science and Engineering, 29(3):035004, 2021.
[2] S. Florez, K. Alvarado, D. Pino Muñoz and M. Bernacki. Computer Methods in Applied Mechanics and Engineering, 367:113107, 2020.
[3] G. Victor, B. Flipon, A. Gaillac and M. Bernacki. https://arxiv.org/abs/2203.08447, 2022.