PhD in materials science : dynamipc precipitation in aluminium alloys (M/F)

The PhD thesis, under CNRS contract, will be carried out within the doctoral school IMEP2 of Université Grenoble Alpes
https://www.adum.fr/as/ed/page.pl?site=edimep2&page=accueil
The Science and Engineering of Materials and Processes laboratory is a mixed research unit between CNRS, Grenoble INP and UGA. It brings together an average of 240 people, including 70 researchers and academics, 42 engineers, technicians and administrative staff and 130 PhD students, post-doctoral fellows, guests and trainees. This group of physicists, mechanics and chemists of materials and fluids studies the elaboration, the shaping, the assembly and the properties of materials with structural and functional applications (energy, microelectronics, etc...) by combining experimentation and modelling, from the atomic scale to the scale of the process, by relying on the mutualisation of experimental platforms of elaboration and characterisation.
The researchers :
- design and optimize innovative elaboration processes,
- design, develop and characterize the materials of the future, but also improve the properties of existing materials.
This research strategy, which combines the building blocks of elaboration, modeling, characterization and properties of use, is one of the strong points of the laboratory, which has organized itself so that the various disciplines present are interactive.

The laboratory relies on four research groups that perpetuate the basic sciences in physics and physical chemistry, thermodynamics and kinetics, solid and fluid mechanics:
- GPM2: Physical and Mechanical Engineering of Materials
- PM: Metal Physics
- TOP: Thermodynamics, Modeling, Process Optimization
- EPM: Elaboration by Magnetic Processes
This thesis will take place within the Metal Physics group.
More information about publications, organization and valorization can be found on the laboratory website: http://simap.grenoble-inp.fr/accueil/ .

Translated with www.DeepL.com/Translator (free version)

Nanometric precipitation is the most efficient way to increase the yield strength of aluminium alloys and as such is of fundamental interest for the lightening of structures in the field of transport (automobile, aeronautics), which is essential for reducing vehicle emissions. The formation of these precipitates requires heat treatments during which the diffusion of solutes is activated and allows the precipitates to nucleate and grow. These processes are strongly modified when the alloy is plastically deformed, leading to a change in the precipitation state during plasticity, called dynamic precipitation. From a practical point of view, dynamic precipitation is encountered in many processes such as the hot forming of automotive structural parts, which allows the use of aerospace alloy grades and the replacement of parts currently made of steel.
Several mechanisms can control dynamic precipitation: acceleration of diffusion by non-equilibrium concentration of vacancies, accelerated nucleation, diffusion along dislocations, or even shearing of precipitates. Although these mechanisms have all been observed, there is no experimental and theoretical framework to predict their relative importance in a given situation (alloy, initial state, temperature, strain rate), and thus to determine the associated precipitation kinetics.
The proposed thesis will take place within the framework of a project funded by the French National Research Agency, aiming to study and control dynamic precipitation in aluminium alloys. This project will include two parallel theses, one mainly based at SIMAP (object of the present proposal), the other at MATEIS in Lyon (focusing on dynamic precipitation under cyclic conditions). The two theses will be carried out in close collaboration, with reciprocal stays in the two laboratories to use specific equipment and frequent exchanges.
The first axis of the thesis will be experimental. The aim will be to build an understanding of dynamic precipitation kinetics covering a wide range of starting metallurgical state, temperature and strain rate conditions. Precipitation will be studied mainly in-situ during hot deformation using small angle X-ray scattering (SAXS), conducted in the laboratory for slow rates and at the synchrotron for fast rates. These quantitative and in-situ analyses will be complemented by transmission electron microscopy and tomographic atom probe observations. The alloys studied will be 7000 series (Al-Zn-Mg-Cu) alloys with low precipitates of low aspect ratio and 2000 series (Al-Cu) alloys with platelet precipitates, where different phenomena are expected.
The second focus of the thesis will be the modelling of the observed kinetics. Based on existing precipitation models, the aim will be to include deformation-dependent mechanisms (such as vacancy supersaturation or shearing of precipitates) to build a predictive model.

Desired candidate:
A degree in engineering or a master's degree in materials science and engineering, with experience in metallurgy is preferred. The thesis will require a taste for fine experimentation and instrumentation, as well as minimal knowledge in programming (data processing, modelling), and will involve teamwork (strong interactions with the other thesis of the project).