PhD - Phase-Field Modelling of Martensitic Transformation in TRIP Refractory High-Entropy Alloys

PhD - Phase-Field Modelling of Martensitic Transformation in TRIP Refractory High-Entropy Alloys 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 hindered 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 crucial to overcome the strength‑ductility trade‑off enabling next‑generation high‑temperature structural materials.

Scientific objectives This internship is part of a broader ANR (French National Research Agency) project “BADTRIP” aimed at understanding the micro‑mechanical and micro‑structural mechanisms governing martensitic transformation in TRIP‑type RHEAs at room temperature.

The specific goal of this internship is to develop and validate a 3D phase‑field model capable of describing:

The early stages of martensitic transformation in RHEAs.

The growth and interaction of martensitic variants within a metastable β matrix.

The coupling between transformation‑induced strains and plastic relaxation of the matrix.

Ultimately, the results will help establish physically based criteria for predicting TRIP behaviour in RHEAs.

Responsibilities

Familiarize yourself with an existing

multi‑phase‑field model

for martensitic transformations.

Extend the existing model to include

plastic relaxation

of the β matrix.

Calibrate input parameters (lattice constants, elastic constants, free energies, yield stresses, etc.) from literature data.

Perform

numerical simulations

to investigate the effect of mechanical loading on the microstructural evolution.

Analyse 3D simulation outputs and compare with available experimental data.

Requirements

Physics » Computational physics, Classical mechanics, Thermodynamics.

Master Degree or equivalent.

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.

Université de Lorraine promotes innovation through the dialogue of knowledge, taking advantage of the variety and strength of its scientific fields…

#J-18808-Ljbffr