A thesis is proposed by MATEIS (INSA-Lyon) and IM2NP (AMU), in the framework of the project ANR NANOTRIP.

Subject:

Transformation induced plasticity in zirconia: characterization at small scales by X-ray diffraction and in-situ electron microscopy during mechanical loading.

Objective of the thesis:

The objective of this thesis is to better understand the tetragonal-monoclinic phase transformation mechanism at the origin of this transformation-induced plasticity. For this, in situ mechanical tests on micro-pillars in Scanning Electron Microscopes and in combination with synchrotron X-ray diffraction will be performed.

The thesis project therefore aims to:

– Develop cerium oxide doped zirconia exhibiting a TRIP effect, with grain sizes (microstructures) compatible with the fabrication of micro-pillars and small samples for micromechanical tests in the broad sense,

– Perform micrometric-sized samples (micro-pillars, but also potentially micro-beams or other suitable geometries) by focused ion beam (FIB) micromachining,

– Carry out ex-situ mechanical tests followed by microstructural analyzes. Later on, in-situ tests in a scanning electron microscope, in order to obtain the constitutive laws of micro-pillars cut from a single grain or presenting interfaces to better understand the criteria for the transformation and transmission from grain to grain,

– Develop in situ synchrotron X-ray diffraction experiments on micro-pillars (Laue microdiffraction, coherent diffraction imaging and phase mapping, etc.), in particular within the framework of tests carried out on synchrotron beamlines.

In general, the thesis will provide a better understanding of the conditions / criteria for nucleation of the monoclinic phase and its transmission across grain boundaries, the constitutive laws associated with the transformation at small scales or the effects of the level of cerium on the transformability (critical transformation constraint).

Your profile:

– Either a training in “material science”, with proven experience (internship, end-of-study project) in the field of design and / or use of advanced characterization methods like X-ray diffraction and electron microscopy, with a passion for the understanding of the underlying physics of phenomena.

– Or training in "Condensed Matter Physics", with experience in the field of relationships between microstructures and material properties.

– Experience in in situ testing at the microscale would be a plus.

Applications (Cover letter + CV) to be sent exclusively to:

Jerome.chevalier@insa-lyon.fr and olivier.thomas@im2np.fr

Imperatively with the subject: ANR NANOTRIP Mesis - application First name Last name

More information are available in the following documents:

- In English: « Sujet de thèse NANOTRIP_english.pdf »

- In French: « Sujet de thèse NANOTRIP_français.pdf »