Phase-Field Modelling of Martensitic Transformation in TRIP Refractory High-Entropy Alloys M/F

Job Description

Thesis Subject

Refractory high-entropy alloys (RHEAs) and complex concentrated alloys (RCCAs) are subclasses of multi- principal element materials with high strength and thermal stability at both ambient and high temperatures. These alloys, typically formed from transition metals of Groups IV (Ti,Zr,Hf) and V-VI (V,Nb,Ta,Cr,Mo,W) crystallize in a body-centered cubic (β) solid-solution phase. Despite their excellent high- temperature performance, their limited room-temperature ductility and low work-hardening rates has limited practical applications.
Recent advances have revealed that transformation-induced plasticity (TRIP) can significantly improve ductility and work-hardening in certain RHEAs, particularly those containing Group IV elements (Ti, Zr, Hf). Understanding and controlling this TRIP effect is essential to overcome the strength-ductility trade-off to design the next-generation of high-temperature structural materials.

The PhD is part of a broader ANR (French National Research Agency) project “BADTRIP” aimed at understanding the micromechanical and microstructural mechanisms governing martensitic transformation in TRIP-type RHEAs at room temperature. This PhD will be carried out in collaboration with the Laboratoire d'Étude des Microstructures (LEM), a mixed unit between CNRS and the French national
aerospace research center (ONERA).
The objectives of the PhD project is to develop and validate a 3D phase-field model capable of describing:
- The early stages of martensitic transformation in RHEAs.
- The nucleation, growth, and interaction of martensitic variants within a metastable β matrix.
- The coupling between transformation-induced strains and plastic relaxation occurring in the surrounding matrix.
Based on the results obtained from the phase-field simulations, a cellular automaton model will be developed to predict the mechanical properties of the RHEAs at larger scales.
Ultimately, this work aims to establish physically-based criteria for predicting TRIP behaviour in RHEAs to help guide the design of high-performance alloys.

Main tasks :
- Familiarize yourself with an existing multi-phase-field model for martensitic transformations and extend the existing model to include plastic relaxation of the β matrix. Perform numerical simulations to investigate the effect of mechanical loading on the microstructural evolution ;
- Develop a cellular automaton model to access the mechanical properties of the polycrystalline material ;
- Analyse 3D simulation outputs and compare with available experimental data obtained by BAD TRIP consortium.

Skills/Qualifications :
- Strong background in metallurgy, materials science, solid mechanics, or computational physics ;
- High interest in numerical methods and scientific programming (e.g., Python, Fortran) ;
- Knowledge of phase field modelling is appreciated;
- Good written and spoken English and/or French.

Your Work Environment

The Institute Jean Lamour (IJL) is a joint research unit of CNRS and Université de Lorraine.
Focused on materials and processes science and engineering, it covers: materials, metallurgy, plasmas, surfaces, nanomaterials and electronics.
By 2026, IJL has 258 permanent staff (33 researchers, 133 teacher-researchers, 92 IT-BIATSS) and 389 non-permanent staff (146 doctoral students, 43 post-doctoral students / contractual researchers and more than 200 trainees), from some seventy different nationalities.
Partnerships exist with 150 companies and our research groups collaborate with more than XX countries throughout the world.
Its exceptional instrumental platforms are spread over 4 sites ; the main one is located on Artem campus in Nancy.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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