Missions

The candidate will work, within UMR CNRS 5801 LCTS (Laboratory of ThermoStructural Composites), on thermomechanical and thermophysical characterizations of monofilaments (fibers) of carbon and silicon carbide.

General framework of the study: Carbon (C) and silicon carbide (SiC) fibres (monofilaments) are used in C/C or CMC composite materials (ceramic matrix composites) by the aerospace industry (brake discs, rocket engine nozzles, thrust chambers, leading edges,...) with high temperature structural applications. Knowledge of thermomechanical properties (coefficient of thermal expansion) and thermophysical properties (diffusivity, heat capacity, thermal conductivity) of the different constituents is essential to supply material data to the digital models used to design industrial parts, and to understand their behavior under mechanical, environmental, and thermal stresses. Moreover, being able to correlate these properties with each other and link them to the microstructure of the fibers is an essential element for the development of new materials.

Objective: The proposed work is part of the objective to feed the databases with properties of C and SiC fibers using an original characterization method available at LCTS. The test bench has been designed, developed and improved in several stages and continues to evolve. It will therefore be a question of carrying out the necessary technical upgrades and optimizing (fine-tuning) the different characterizations on reference fibers. This device has given satisfaction on the C fibers; however, adaptations and validation of the means will be necessary in order to work on SiC fibers.

Activités

- Bibliographical study on the thermal characterization of C and SiC fibers
- Training on bench use (in particular heating techniques by Joule effect, laser diffraction, infrared imaging, pyrometry, preparation of micrometric samples, ...)
- Technical upgrade, optimization of the bench
- Feasibility on SiC fibers
- Characterization of various C and SiC fibers
- Relationships between their properties
- Write protocols, experimental reports and present the results (publication, presentation at a symposium, ...)

Compétences

Required scientific & technical background :
- Materials science (theory, practice), with emphasis on composites and CMC
- Materials characterization, including thermal and mechanical properties
- Experimental practice; instrument control and acquisition; data analysis and processing
- Curiosity, autonomy, rigor and thoroughness, good aptitude to teamwork.

Contexte de travail

LCTS is a joint lab of CNRS, Bordeaux University, CEA and Safran, located on the Bordeaux Campus. It has 36 years of experience in basic science research on refractory composites. These high-performance materials are used in aviation, space, energy & industrial applications. LCTS is single research team working in project-oriented mode, in strong relation with its non-academic stakeholders. Currently it includes 36 permanent staff members, plus some 15 PhD candidates and 4 post-doc researchers

Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.

Contraintes et risques

- Work with a class 3B laser : prior medical examination of the eye background ; specific training to the use of the laser - all paid by CNRS
- Chemical risk
- Isolated work risk