Oxygen Embrittlement In The Tial System: Dft Approach

Universities and Institutes of France
November 01, 2022
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Contract Type:Temporary
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  • Organisation/Company: CIRIMAT, CNRS, Toulouse INP, University Paul Sabatier Toulouse 3
  • Research Field: Physics › Chemical physics Physics › Computational physics Physics › Solid state physics
  • Researcher Profile: First Stage Researcher (R1)
  • Application Deadline: 01/11/2022 00:00 - Europe/Brussels
  • Location: France › Toulouse
  • Type Of Contract: Temporary
  • Job Status: Full-time
  • Hours Per Week: 37
  • Offer Starting Date: 01/01/2023
  • An 18-month post-doctoral position in simulation is open at CIRIMAT (Toulouse), available from January 2023.

    Context and scientific objectives

    The objective of this project is to design new TiAl alloys with improved resistance to high temperature exposure in air, which are the typical service conditions of key applications in the aeronautical sector (turbine blades). Indeed, this issue is at the heart of current concerns to expand the industrial use of intermetallic materials in aircraft engines. One of the main limitations concerns the penetration of oxygen, which has a very negative impact on the mechanical properties at room temperature and at high temperature and leads to a reduction of the material lifetime. To reduce this negative effect, an alloy design strategy is implemented in the project, based on theoretical approaches followed by experimental validations.

    In the framework of this project, we are looking for a post-doctoral fellow to help us answer different theoretical

    questions related to this oxygen embrittlement. Three research axes are proposed during this post-doc. The first work concerns the study, by means of ab initio simulations, of the interactions between oxygen and dislocations in order to understand the influence of oxygen on plasticity. This work follows the thesis work of C. Thenot which will be defended at the end of 2022 1-3. The second task will be to study the results of oxygen diffusion in TiAl in the presence of solutes acting as traps for the diffusion. Currently, a simplistic approach was used to evaluate this effect in the case of substituted solutes (such as W, Mo, etc.), using an Oriani type model 2. We would like to confirm these results with more accurate methods. Finally, the last task will be to study by means of DFT the diffusion of these substituted solutes in the γ-TiAl phase. The objective is to have information on the diffusivity of these species, to verify the stability of the solid solution during long term aging heat treatments at high temperatures.

    Funding: The post-doctoral fellow will join a collaborative project DEMENTIAL, funded by the French ANR program.

    Remuneration: according to experience

    Required skills: We are looking for a motivated candidate with a Ph.D. in materials science, physics, or a related discipline. Previous experience in the study of defects (point, dislocations, or grain boundaries) in crystalline solids using atomic scale simulations is a plus.

    Contact: Please send a cover letter and a complete CV with references, contact to Damien Connétable ( damien.connetable@ensiacet.fr ).

    Practical information: CIRIMAT is located in the southwest of France, in Toulouse.

    Selected candidates will be invited to a motivation interview. After the interviews, the selected candidates will be ranked and the ranking can be discussed with the other people involved in the project.

    References :

  • “Interactions of oxygen with intrinsic defects in L10 γ-TiAl in presence of substitutional solutes: influence on diffusion kinetics.'', C. Thenot, et al., Computational Materials Science 201 (2021) 110933. https: // doi.org/10.1016/j.commatsci.2021.110933.

  • “Theoretical study of the oxygen insertion and diffusivity in the γ-TiAl L10 system." D. Connétable, et al., Journal Physics: Condensed matter 32 (2020) 175702. https: // doi.org/10.1088/1361-648X/ab6a2f.

  • C. Thenot “Role of oxygen in the high temperatures embrittlement of TiAl: insertion, diffusion and interaction with the dislocations”, PhD University of Toulouse (2022).

  • Required Research Experiences
  • RESEARCH FIELD
  • Physics › Solid state physics

  • YEARS OF RESEARCH EXPERIENCE
  • 4 - 10

    Offer Requirements
  • REQUIRED EDUCATION LEVEL
  • Physics: PhD or equivalent

    Computer science: PhD or equivalent

  • REQUIRED LANGUAGES
  • FRENCH: Basic

    Skills/Qualifications

    We are looking for a motivated candidate with a Ph.D. in materials science, physics, or a related discipline. Previous experience in the study of defects (point, dislocations, or grain boundaries) in crystalline solids using atomic scale simulations is a plus.

    Specific Requirements

    DFT simulations

    Contact Information
  • Organisation/Company: CIRIMAT, CNRS, Toulouse INP, University Paul Sabatier Toulouse 3
  • Organisation Type: Research Laboratory
  • Website: https:// www. cirimat.cnrs.fr
  • Country: France
  • City: Toulouse
  • Postal Code: 31030
  • Street: 4 Allée Emile Monso
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