Prof. Marie Charpagne is Looking for a Grad Student in Experimental Condensed Matter/Metallic Materials

Prof. Marie Agathe Charpagne from MatSE is looking for one motivated graduate student with interest in condensed matter/metallic materials for one experimental project involving small-scale testing of custom-made refractory alloys.

Design, mechanical behavior, and microstructure control in refractory high entropy alloys: Refractory high entropy alloys (RHEAs) are a new class of metallic materials with exciting mechanical properties. Contrary to ‘traditional’ alloys which are always designed using a base element (e.g. Fe for steels), RHEAs possess no base element. Instead, three or more elements in close-to equiatomic proportions are used, which increases the configurational entropy of the alloy, oftentimes stabilizing a single-phase solid solution. The infinite combinations of three or more elements opens a wide compositional space which remains to be explored. While most refractory metals suffer from a lack of ductility at room temperature and a drop in yield strength as the temperature increases, some RHEAs exhibit retained strength up to temperatures exceeding 1000C, which makes them good candidates for applications such as hypersonic flight and rocket engine components. Enabling the use of RHEAs in these structural applications involves basic understanding of their mechanical behavior under loading. Most of these alloys exhibit a body centered cubic (BCC) lattice which possesses no close-packed plane. Therefore, the deformation mechanisms and dislocation motion dynamics that allow plastic deformation in BCC lattices are far from being understood and requires multi-scale investigations ranging from the crystal sale to the atomic scale. In this project, the student will be preparing RHEAs of several relevant compositions in the aim to prepare micro-pillars for in-situ compression in the scanning electron microscope. These experiments will enable to shed light on the phenomenological development of plasticity in RHEAs and provide guidelines for alloy design.