Missions

The phase transitions of tin and iron have been extensively studied in dynamic compression, with widely varying compression rates. A large body of literature exists, but there is disagreement on the transition ranges, the nature of some of these transitions, and their kinetics. The mechanisms involved are complex and are directly impacted by the choice of starting material (impurities, microstructure, crystal orientation, etc.) as well as by the strain rate and triaxiality of the stresses.

Activities

The aim of this postdoctoral position is to produce an up-to-date bibliographic review (a choice between iron and tin may be made depending on the candidate's profile and motivations) and then to combine modelling and complementary experiments to refine our understanding of the phase transition mechanisms at play. To do this, the postdoctoral researcher will use existing hydrodynamic code to simulate experiments from the literature, implement and improve multi-phase behaviour laws to optimise their predictive capabilities, and carry out new laser shock experiments on large instruments (HERA, LULI2000, SACLA, EuXFEL).

Skills

The candidate must hold a PhD in one or more of the following disciplines: - Shock physics, - Phase transition mechanisms, - Materials science. They must also be proficient in one or more of the following techniques: - X-ray diffraction, - Velocimetry, - Thermomechanical/hydrodynamic simulations.

Work Context

The ChocoDyn federation brings together around a hundred researchers in 19 laboratories studying dynamic pressure loads and their effects in a range from a few bars to a few Mbars on time scales from a few nanoseconds to a few milliseconds. The postdoctoral researcher will be assigned to the DCI team in the IPR's Mechanics and Glass Department and will report to Didier Loison. The federation's ambition is to respond to societal challenges related to the durability of materials subjected to these extreme conditions of pressure, speed and temperature. It is also interested in more fundamental questions, for example in the sciences of the universe with hypervelocity impacts or high-pressure phase diagrams. On this latter topic, a working group has been set up and funding for an initial one-year postdoctoral contract has been secured. The working group associated with this project consists of the PPRIME (Poitiers), IPR (Rennes), PIMM (Paris) and CEA (Bruyère le Chatel) laboratories. It will meet regularly to discuss the progress of the work and the next steps to be taken. In addition, the postdoctoral researcher will be required to interact with members of the federation (meetings, online seminars and thematic schools). The position is in a sector covered by the protection of scientific and technical potential (PPST) scheme and therefore, in accordance with regulations, requires your arrival to be authorised by the competent authority at the MESR.