• Supervision: Marc Legros (marc.legros[at]cemes.fr), Julio Cesar Brandelero (Mitsubishi Electric)

    Location: CEMES (Toulouse)

    Financial support: CIFRE Grant (starting on October 1th, 2020 ; 3 years duration).
    Keywords : Al microstructure, oxidation, grain boundaries, thermal & electrical cycling, electron &ion microscopy.

     

    Power devices, such as MOSFETs and IGBTs, are key components of the continuous growth of power electronics applications ranging from domotics to energy conversion. Their reliability becomes critical in transportation and off-shore applications. Anticipating or even preventing their failure is a key technical issue.

    In recent years, several weak spots have been identified in the structure of modern Si-based power devices, and some solutions (packaging) have already been found to increase their resistance to disruption. However, the aging of the top metal source and wire bondings, mainly made of Al or Al alloy has persisted as an intrinsic weak link, degrading the electrical performance of the device over time. This occurs through mechanisms that involve grain boundary diffusion, crack formation and surface/interface oxidation, also driven by stresses arising from thermal mismatch between the metal and the silicon. The goal of this thesis is to find methods (fresh devices processing, circuitry modification) favoring the self-healing or the non propagation of these cracks.

     

    More details HERE

     

    On the Mitsubishi Electric Research site


    your comment
  • DEFORMATION MICROMECHANISMS AND TENSILE PROPERTIES OF ADVANCED SINGLE CRYSTAL NICKEL-BASED SUPERALLOYS

    Supervision: Jonathan Cormier (Pprime Institute, Poitiers), Florence Pettinari-Sturmel (CEMES-Université Paul Sabatier, Toulouse)

    Financial support: MESR Grant (starting on November 1th, 2020 ; 3 years duration).

    Keywords : Ni-based superalloys, Mechanical properties, Tensile tests, Deformation micro-mechanisms, Dislocations, Transmission electron microscopy.

    Subject and challenge of the project: Single crystal nickel-based superalloys are widely used for aero- engines components, because of their superior high temperature mechanical resistance in order to fulfill several requirements: i) a high !' solvus temperature; ii) a high amplitude of !/!' mismatch; iii) a density as low as possible and iv) a good phase stability.  A new-generation Pt-containing superalloy has been developed between ISAE-ENSMA/Institut Pprime and SAFRAN in France . This new alloy is considered as a potential alloy for future airfoils.

    The aim of this study is thus to concentrate the efforts on the tensile behavior understanding. Tensile tests will be performed at a given temperature (in the range 500 °C 800 °C) for the three SXs (CMSX-4 Plus, TMS-238 and TROPEA), which differ in chemical composition. The final goal will be to confirm the effect of the chemical composition and to understand how it influences the controlling deformation parameters.

    The experimental approach will consist in the realization of tensile tests at ISAE-ENSMA/Institut Pprime (Poitiers) during the first year. A complete analysis of the microstructure and the deformation micromechanisms will be carried out at CEMES using Transmission Electron Microscopy (conventional TEM, in situ TEM tensile tests, TEM spectroscopies: EELS and EDX), during the next two years. The final goal is to identify and quantify the physical parameters controlling the tensile properties at temperature lower than 800 °C for different SXs.

    More details here

     


    your comment
  • Research Fellow (AMCASH Technical Officer) - 95931 - University of Birmingham, Edgbaston, Birmingham UK
     
    Area:  School of Metallurgy and Materials in the College of Engineering and Physical Sciences 
    Salary: Full time starting salary is normally in the range £30,942 to £40,322. With potential progression once in post to £42,792 a year.  Please note that as this vacancy is externally funded, the maximum salary available is £30,942 per annum.
    Hours: Full time 
    Duration: Fixed Term Contract up to 31 March 2023
    Location:  University of Birmingham, Edgbaston, Birmingham UK
    Closing date: 17 April 2020
     
    Job Summary
    This vacancy is funded by the European Regional Development Fund. Please note, there are three posts available.

    This post will create and contribute to the creation of knowledge by undertaking a specified range of activities within an established research programme and/or specific research project. For more information about AMCASH please visit

    https://www.birmingham.ac.uk/partners/sme-support/Business-Support-Programmes/amcash.aspx and http://www.amcash.co.uk

     

    The post holder’s primary objective will be to ensure that the suite of technology demonstrators to be delivered in the project meet the needs and expectations of stakeholders and provide a compelling case for the uptake of manufacturing simulation and material characterisation by regional manufacturing SMEs.

     
    Main Duties
     
    For one position, the mission consists in 40% standard microstructural characterization using TEM, SEM, Optical Microscope etc . And 60%  focus on experiments of in-situ straining of metallic samples including Mg, Ti and engineering alloys such as Ni base superalloys. Background experience of TEM study of dislocations would be appreciated
     

    The responsibilities may include some but not all of the responsibilities detailed here.

    Informal enquiries to Dr Yu Lung Chiu, y.chiu@bham.ac.uk or telephone 0121 414 5190 


    your comment
  • Missions / PhD topic

     

    The successful candidate will join the I3EM (“In situ, Interferometry and Instrumentation for Electron Microscopy”) team at CEMES-CNRS and will study the modifications of electric and magnetic fields by light absorption in nanostructured semiconductor materials using in situ electron holography.

    •   Supervisors: Sophie MEURET (sophie.meuret@cemes.fr) and Christophe GATEL (christophe.gatel@cemes.fr)

    •   URL official offer : https://bit.ly/3bNIfNU

    •   Workplace: TOULOUSE

    •   Type of Contract: PhD

    •   Contract Period: 36 months

    •   Expected date of employment: 1 October 2020 but flexible

    •   Proportion of work: Full time

    •   Remuneration: 2135€ brut/month

    •   Desired level of education: Master

    • More details here

     


    your comment
  • The Kacher Lab is currently looking for a dynamic researcher to aid in our efforts to understand the multiscale microstructural effects dictating the mechanical behavior of materials. As a team, we explore how microstructure and processing conditions affect bulk properties and local failure mechanisms using multiscale and in situ-based electron microscopy techniques. Currently, we are accepting applications for a post-doctoral position focused on understanding dislocation mechanics at the micro to nanoscale under a range of loading conditions. The work will involve in situ TEM using a custom-built quantitative micromechanical testing platform and post mortem analysis of dislocation/grain boundary interactions. The position is available beginning in August 2020 and will continue for one year from hire date, with yearly extensions to a second and third year possible depending on performance and funding.

    Required Qualifications:

    • A Ph.D. in Materials Science and Engineering, Mechanical Engineering, Physics, or a related discipline.

    • Excellence in written and oral communication as evident by a strong publication and presentation track record.

    • Expertise in electron microscopy-based characterization

    Desired Qualifications:

    Strong candidates will have experience in at least some of the following areas:

    • TEM-based dislocation characterization

     

    • EBSD-based analysis of microstructure and defect structures
    • FIB-based TEM sample preparation
    • In situ TEM nanomechanical testing
    • Fatigue testing and failure analysis
    • Corrosion/stress corrosion cracking

    Interested candidates should send a cover letter, CV including a list of publications and presentations, three potential references with phone numbers and emails included to Prof. Josh Kacher (josh.kacher@mse.gatech.edu). Reviews of applications will begin immediately and will continue until the position is filled.


    your comment