Missions

The PPM group at CEMES is looking for phD candidates for a one year position
within the ANR project DoReMi (IRCP – ICMPE – LSPM – CEMES).

Activities

The applicant is expected to perform in-situ heating and straining TEM experiments, write reports and communicate about the work to international audiences.

Skills

Strong interest in the field of physical metallurgy and demonstrated skills in TEM
(conventional imaging, electron diffraction) are required. Working experience for analyzing defects in TEM and sample preparation (conventionnal, FIB) will be appreciated. Ability to communicate clearly on the technical areas concerned by adapting to the interlocutors and to discuss constructively the progress of the project

Work Context

Future aeronautic and aerospace applications will require materials able to sustain
very high temperatures, i.e in the range 1200°C – 1600°C under mechanical loading. Over the last two decades, research efforts have been made directed to break with the conventional alloy design (addition of solute atoms to a principal base-element), and have led to the breakthrough concept based on multi-principal elements, mixed in (near) equiatomic proportions and stabilized by high-entropy [COU]. Among the potential candidates for high-temperature (HT) applications, the refractory complex concentrated alloys (RCCAs) with body-centered cubic (bcc) based structure have received an increasing attention, but they still lack strength above 0.6Tm, making them difficult to use for applications at very high temperature.
In the present project, DoReMi, standing for “Development of New Advanced Refractory
Concentrated Complex Alloys with Eutectic Carbide/BCC Microstructures”, we propose to develop a new type of alloy that benefits from the properties of both RCCAs for toughness and carbide for ultra high strength. A recent study reports indeed excellent and promising properties [WEI]. However, the field of investigation is currently blank and the carbide eutectic RCCA concept still needs to be rationalized, raising fundamental questions, especially regarding thermal stability and underlying deformation mechanisms. This position hence aims at deciphering elementary plasticity mechanisms. In links with partners of the project; we will perform in-situ micromechanical tests inside a transmission electron microscope (TEM), a renown technique at CEMES [MOM], in order to observe deformation mechanisms in a
wide range of temperatures and on different eutectic alloys, and try to correlate them with macroscopic mechanical tests. A special interest will be paid to bcc plasticity and strain accommodation at the bcc-carbide interface.

Ref:
[COU] : Senkov, O. N. ; Miracle, D. B. ; Chaput, K. J. ; Couzinie, J.-P., J. Mater. Res. 2018, 33
(19), 3092-3128. https://doi.org/10.1557/jmr.2018.153.
[MOM] : Legros, M. ; Mompiou, F. ; Caillard, D. Nat. Mater. 2024, 23 (1), 20-22.
https://doi.org/10.1038/s41563-023-01739-2.
[WEI] : Wei, Q. ; Xu, X. ; Shen, Q. ; Luo, G. ; Zhang, J. ; Li, J. ; Fang, Q. ; Liu, C.-T. ; Chen, M. ;
Nieh, T.-G. ; Chen, J. Sci. Adv. 2022, 8 (27), 2068. https://doi.org/10.1126/sciadv.abo2068.

The position is located in a sector under the protection of scientific and technical potential (PPST), and therefore requires, in accordance with the regulations, that your arrival is authorized by the competent authority of the MESR.