- Amphithéâtre 2 (bâtiment A), Arts et Métiers campus Metz, 4 rue Augustin Fresnel, 57070 Metz
anglaisPanel
- Jean-Phillipe Couzinié (ICMPE Paris, rapporteur)
- Joao Pedro Oliveira (Universidade Nova de Lisboa, rapporteur)
- Myriam Dumont (Arts et Métiers Lille, examinatrice)
- Jérémie Bouquerel (Centrale Lille, examinateur)
- Adil Benaarbia (Centrale Lille, directeur de thèse)
- Léo Thiercelin (Arts et Métiers Metz co-encadrant)
- Laurent Peltier (Arts et Métiers Metz co-encadrant)
- Eric Fleury (Université de Lorraine, invité)
- Nathalie Siredey-Schwaller (Université de Lorraine, invitée)
Mots clés : Dissimilar bonding, Multi-component alloys, Austenitic stainless steel, Multiscale experimental characterisation
Abstract
Multi-component alloys (MCAs) are well known for their unique physical, chemical and mechanical properties at extreme temperature conditions. Equiatomic CoCrFeMnNi high entropy alloy (HEA) and its subsystems are potential materials that can be used in structural applications. This investigation was carried out to assess the joint integrity of dissimilar diffusion bonding of some FCC-structured equiatomic multi-component alloys (CoNi, CoCrNi, CoCrFeNi and CoCrFeMnNi) to 316L stainless steel (SS316L). The microstructures and chemical gradients across the bond interfaces were examined by a Scanning Electron Microscope (SEM) equipped with an Energy Dispersive Spectrometer (EDS), Electron Back Scattered Diffraction (EBSD) and X-ray Diffraction (XRD) analyses. The mechanical properties of the joints were assessed by hardness measurements at the micro- and nanoscale and shear tests.
The diffusion of the major constituent elements was modelled based on Fick’s second law of diffusion. The effect of bonding temperatures was further investigated to optimize the diffusion bonding. The dissimilar joints produced at optimum conditions preserved a single face-centred cubic (FCC) phase at the diffusion zones, which were characterised by low interfacial defects and without major compositional segregation or formation of secondary intermetallic compounds. Dissimilar joints of S316L-CoCrNi and SS316L-CoCrFeNi were the most superior as they offered good shear strengths, fracture energies and ductility comparable to that of SS316L similar diffusion bonded joint.
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