Postdoc in Materials Science: Processing and Characterization of Chemically Architectured Metallic

For many industrial applications as energy production, aeronautics or automotive sectors, materials are submitted to more and more severe environment. Thus, in order to obtain a breakthrough in properties, new families of alloys and new strategies of strengthening are needed. This project proposes fluctuations of chemical composition as a new strengthening mechanism in order to combine the functionalities of high mechanical strength, high ductility and high damage resistance. High entropy alloys (HEA) have been selected as good candidates to apply this new strengthening mechanism. HEA is a relatively new family of metallic alloys, which are multi-components and in which all components are very concentrated.

In other words, the traditional distinction between major and minor elements is not relevant anymore for HEA. Applying the strengthening mechanism of composition fluctuations to HEA leads to a chemically architectured microstructure: (a) multi-component solid solutions at the nanoscale; (ii) grain boundaries at the submicron scale, (c) continuous composition gradients at the micron scale and (d) inter-connected network of the two phases and of the interphase at the mesoscale. The general objectives of the project are (i) to assess the efficiency of composition fluctuations as a new strengthening mechanism and (ii) to identify and optimize the microstructural parameters which control this strengthening mechanism.

This project is funded by a starting grant from the French National Agency for Research (ANR). The project coordinator of the project is Ms Mathilde Laurent-Brocq, from Institute of Chemistry and Materials of Paris East (ICMPE). Two teams of ICMPE as well as another one of the Material Center of Mines de Paris are involved. In addition with the permanent employees of those teams, two post-doctoral positions and one master internship will be funded by this project.

Post-doc description

The objective of this post-doctoral position is to understand the processing of chemically architectured HEA and to characterize them. More specifically, chemically architectured HEA are processed by powder metallurgy (gas atomization, spark plasma sintering). It is needed to establish the link between the numerous processing parameters and the numerous characteristics of the microstructure. A multi-scale characterization will permit to fully describe chemically architectured HEA, with a focus on chemical fluctuations. Among other techniques, X-ray diffraction, scanning and transmission electron microscopy coupled with energy dispersive microscopy will be used. The first mechanical tests will also be performed during this post-doc and the second post-doc will deal with those tests in depth. Some results about processing and characterization were already obtained by the teams involved in the project. They will serve as a starting point.

Practical information

Duration of the position: 18 months

Starting date: between January and March 2019

Location: ICMPE, 2-8 rue Henri Dunant, 94320 Thiais (South of Paris) FRANCE

Salary : gross = 2605 €/month ; net = 2129 €/month

Funding of the project: starting grant from the French National Research Agency (ANR)

Application: please send a resume (including a list of scientific communications and at least two references) and a personal letter to Ms Mathilde Laurent-Brocq.