PhD opportunities

Physical modelling of the anomalous viscoplastic behaviour at finite strains: Portevin-Le Chatelier effect and ductile fracture

Thesis proposal

Area of expertiseMechanics
Doctoral SchoolISMME - Systems Engineering, Materials, Mechanics, Energy
SupervisorM. Samuel FOREST
Research unitCentre of materials
ContactFOREST Samuel
Starting dateOctober 1st 2021
KeywordsSimulation, Experiments, Anomalous viscosity, dynamic strain ageing, Portevin-Le Chatelier effect, ductile fracture
AbstractNickel-based superalloys for aircraft engine turbine discs exhibit inverse strain rate sensitivity in part of the service temperature range. This is a manifestation of the dynamic strain ageing phenomenon that results from the competition between dislocation sliding, interaction with the forest and diffusion of solutes in the alloy. The most obvious expression of dynamic ageing is the Portevin-Le Chatelier effect which results in oscillations in the tensile curve and the propagation of plastic strain rate bands along the length of the specimen and in the components. The impact of this effect on the ductile failure of these materials is investigated. For this purpose, a physical model of this phenomenon will be proposed, based on the macroscopic model already available from the project partners. It will focus on the analysis at the granular scale of the polycrystal using numerical simulations by finite elements and in situ experiments under SEM. It will be validated using macroscopic mechanical tests under complex loading (relaxation, field measurements, analysis of ductile failure).
ProfileEngineer and / or Master of Science - Good level of general and scientific culture. Good level of knowledge of French (B2 level in french is required) and English. (B2 level in english is required) Good analytical, synthesis, innovation and communication skills. Qualities of adaptability and creativity. Teaching skills. Motivation for research activity. Coherent professional project.

Prerequisite (specific skills for this thesis):
Continuum mechanics, Computational Mechanics, Mechanics and physics of materials

Applicants should supply the following :
• a detailed resume
• a covering letter explaining the applicant’s motivation for the position
• detailed exam results
• two references : the name and contact details of at least two people who could be contacted
• to provide an appreciation of the candidate
• Your notes of M1, M2
• level of English equivalent TOEIC
• Passport

to be sent to
FundingConvention CIFRE