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Reference : UMR6634-CHRVUR-019
Workplace : ST ETIENNE DU ROUVRAY CEDE
Date of publication : Tuesday, May 19, 2020
Scientific Responsible name : Clément KELLER
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 October 2020
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
In the framework of the NiChroFab project (LABEX EMC3) and RIN DOC LABEX,
Investigation of the viscoplastic deformation mechanims of Ni20Cr alloy obtained by additive manufacturing
The current knowledge of the properties in metallic materials elaborated by Additive Manufacturing (A.M.) mainly concerns titanium alloys, cobalt-chromium alloys, nickel-based alloys, aluminum alloys and steels. Many metals and alloys remain little or not studied, which is the case of the Ni20Cr alloy. This alloy is currently available in the form of rolled or drawn products. However, certain industrial sectors, for instance in the field of electric transport, are considering the possibility of producing these alloys by additive manufacturing. On one hand, new microstructures related to additive manufacturing are expected to improve the mechanical properties of this alloy. On the other hand, the use of additive manufacturing may help to better control the production of specific Ni20Cr parts. Since the Ni20Cr alloy is often used for the production of heating elements or thin products, several questions arise:
1/ Are creep properties modified in case of an A.M. Ni20Cr alloys ?
2/ What is the thermal stability of the A.M. microstructure ?
3/ What is the optimal elaboration strategy in case thin parts ?
4/ Are the deformation and damage mechanisms similar for A.M. and conventional alloys ?
5/ Is a post elaboration heat-treatment necessary properties optimization ?
The objective of this thesis, related to a LABEX project between the GPM and the CRISMAT, is to analyze in detail the properties of the Ni20Cr alloy developed by additive manufacturing. To this aim, first, mechanical tests (monotonous and creep at different temperatures) will be performed to analyse the mechanical properties. Second, analysis by transmission electron microscopy (conventional and analytical mode) on the initial microstructure and after different levels of deformation will be performed to investigate the deformation mechanisms and to understand the role played by the A.M. microstructure on these properties.
The GPM (Materials Physics Group, UMR CNRS 6634) is structured into 5 departments: Materials-Aging-Mechanics, Scientific Instrumentation, Nanosciences, Disordered Systems-Polymers and Nano-Health-Physics. It brings together 160 staff members including 60 Teacher-Researchers / Researchers, 30 ITAs and 70 Doctoral Students / PostDocs / Internships. The laboratory is located on the Rouen Normandy Science and Engineering Campus, within the University of Rouen Normandy and the INSA Rouen Normandy (7000m2).
The recruited doctoral student will be attached to the Materials, Aging and Mechanics department between the ERAFEN (dedicated to the study of phase transformations) and ERMECA (dedicated to the study of the mechanical behavior of materials) teams.
The candidate must have an engineering degree or a master's degree in research oriented towards the mechanics of materials. He/she must have a strong affinity for experimental work and demonstrate autonomy.
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