There is currently a post-doctoral position available for a motivated individual in materials sciences at the laboratory ICB,Dijon, France ( http://icb.u-bourgogne.fr). The position is available immediately and funding by the ISITE I-HTT project. The successful candidate is expected to hold a PhD degree in material sciences, condensed matter physics, chemical physics, physical chemistry, or equivalent. Candidates should have programming skills (fortran, matlab or C, C++) and background in DFT or Molecular Dynamics simulations. The post-doc appointment is initially for one year and could be extended for a second onedepending on mutual agreement and funding. Previous experience with advanced modeling/simulations techniques is requested. 

 

The interested candidates should send (in PDF-format) their curriculum vitae (/including/ nationality, date of birth, civil state, and achieved degrees) and two names of references to Olivier Politano and Virgil Optasanu by email ([email protected], [email protected]). Only complete applications with appropriate name of references will be processed. The selection process will continue until a suitable candidate is found.

Research topics

Due to its very small size, Hydrogen atoms easily diffuse into many metals by interstitial mechanisms. Then it forms a metal-hydrogen solid solution. When the hydrogen content dissolved inside the crystalline lattice is sufficient, it can be combined with the metal to form a metallic hydride. This case appears with Titanium, Zirconium, Tantalum and Vanadium for example. The presence of hydrogen inside the metallic material affects its physico-chemical and mechanical behaviors, modifying the deformation and/or transformation yields beyond which the component weakens. So, hydrogen being present within the alloy under soluble form or hydride form, this embrittlement is hazardous for the component integrity, mostly when subjected to fatigue and/or high temperatures. Each step of a product realization being a source of hydrogen absorption, it is necessary to optimize the manufacturing processes of welded thin tubes in order to reduce its content in the material. As these Ti products are potentially submitted to severe environments (temperature, pressure, surroundings), both their initial content in hydrogen and capability to resist to its absorption within conditions in service are crucial elements. According to this industrial issue, this project aims at the development of numerical approaches to investigate the diffusion of hydrogen and the formation of a metallic hydride in the volume or at the grain boundaries in Ti. Two approaches will be developed :

1) At the atomic scale, molecular dynamics is a perfect candidate to study atomic diffusion mechanisms in a bulk materials and grain boundaries. Atomic interaction potentials have already been proposed for such system and applied to the study of the dissolution of hydrogen in titanium. We will numerically study diffusion of H in atomistic titanium samples. The diffusion coefficient of hydrogen in volume and grain boundaries will be computed. The diffusion path will be characterized. The developments by molecular dynamics at the atomic scale and the results will provide data for simulations on a macroscopic scale,

2) At the macroscopic scale, models coupling chemistry, mechanics and material diffusion applied to the oxidation of metals will be transposed to the case of Ti. Data such as the relationship between the trapping density and the plastic deformation will be required. This last shall be determined experimentally by studying the permeation of hydrogen through the sample.