Organisation/Company: Ecole Nationale Supérieure des Mines de Saint Etienne
Research Field: Technology » Materials technology
Researcher Profile: First Stage Researcher (R1)
Positions: Postdoc Positions
Country: France
Application Deadline: 31 Dec 2024 - 12:07 (Africa/Abidjan)
Type of Contract: Temporary
Job Status: Full-time
Hours Per Week: 40
Offer Starting Date: 1 Mar 2025
Is the job funded through the EU Research Framework Programme? Other EU programme
Is the Job related to staff position within a Research Infrastructure? No
Offer Description The Georges Friedel Laboratory (LGF) is a CNRS Joint Research Unit (UMR 5307). Located at the École des Mines de Saint-Étienne and supported by two supervisory bodies (Mines Saint-Étienne and CNRS), the laboratory brings together all the research potential of Mines Saint-Étienne in the fields of materials, mechanics and processes.
The SMS - Sciences des Matériaux et des Structures - centre is one of five teaching and research centres at Mines Saint-Etienne. Within the LGF, it develops research in materials science, mechanics and advanced manufacturing processes for transport and energy production, with the aim of increasing the durability of materials.
This post-doc is part of the 'SIRA' chair, a four-year partnership between Mines Saint-Etienne and the companies Framatome and EDF, co-financed by the Agence Nationale de la Recherche, focusing on the ageing of low-alloy steels (16MND5) used in the primary circuit components of pressurised water nuclear reactors.
This post-doc is organised around two areas of work. The first involves the analysis of segregation at carbide-matrix interfaces. Carbides play a potentially important role in the initiation of transgranular cleavage and brittle intergranular fracture. In a carbide-matrix interface debonding scenario, the segregation of elements such as phosphorus in these interfaces would therefore reduce the critical stress for the initiation of intergranular fracture, and even that of transgranular cleavage. These interfaces have been little studied, apart from a few SAT studies. We propose to develop a methodology for analysing segregation in these interfaces using STEM-EDX, based on the method developed by C.H. Hsu for grain boundaries. The problem to be solved here is twofold: firstly, we need to develop a method for sampling the FIB plate that will enable us to obtain a vertical, through-hole carbide-matrix interface; we also need to take account of the heterogeneous nature of the interface in the quantification model. Monte-Carlo simulations of the production of X-ray photons in the sample could be used to address this second issue.
The second area of work concerns STEM-EDX analysis of the intergranular segregation of carbon, which is particularly important for at least two reasons: firstly, it could potentially reduce the segregation of phosphorus, through competition for sites; secondly, it would intrinsically improve the cohesion of the joint. However, the carbon segregation measurements on which these hypotheses are based are relatively few and need to be confirmed. Carbon segregation is particularly difficult to analyse using Auger spectrometry because of the presence of nanometric carbides on the fracture surfaces. The aim here is to work on the quantitative analysis of carbon segregation by STEM-EDX, using a methodology identical to that developed by C.H. Hsu for P, Mn, Ni and Mo. The main obstacle to be overcome is the surface contamination of FIB slides by carbon. We need to develop a cleaning method, probably using plasma, to reduce the contamination so that its contribution to the EDX spectrum is not prohibitive for the detection of segregated carbon. It will also be necessary to find analysis conditions that limit the phenomenon of contamination under the beam, and above all, to ensure that the contamination is homogeneous throughout the analysed zone, in order to envisage a method of quantification by subtraction.
The position is based on the Saint-Étienne campus.
Minimum Requirements Holding a doctoral degree in Materials Science or Physics or Chemistry
You have the following skills, knowledge and experience:
Good knowledge of Materials Science
Significant experience in Transmission Electron Microscopy
You recognise yourself in the following abilities and skills:
Ability to work in a team
Ability to interact with academic and industrial partners
Languages: ENGLISH Level Good
Additional Information WHY JOIN US:
Institut Mines-Telecom is characterised by:
A privileged working environment with a high student supervision rate and a high environment rate (support and back-up functions)
First-rate experimental and digital resources
Significant contract research activity (€11m/year in Research and Innovation contracts), mainly with industrial partners
25% international students, Member of the T.I.M.E. network and the EULIST European University
A centre for scientific, technical and industrial culture - La Rotonde - which is unique in France, and which has a major impact on society (> 50,000 visitors per year)
Pleasant workplace, easily accessible by public transport and close to motorways
Public transport costs reimbursed up to 75% (subject to conditions)
Sustainable mobility package
Staff committee that subsidises sports, leisure, cultural and social events and activities
The possibility of partial remote working
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