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Unité Matériaux et Transformations
CNRS UMR 8207 - Université de Lille

Les séminaires de l'UMET

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Séminaire UMET
Mardi 18 Juin 2019 10:00
Didier Long
Laboratoire "Polymères et Matériaux Avancés" Unité Mixte de Recherche CNRS/Solvay 5268
  Damage mechanisms of plasticized cellulose acetate under tensile deformation studied by Ultra Small X Ray Scattering
We consider the microscopic mechanisms of damaging in plasticized cellulose acetate under tensile stresses, how they appear and develop during the course of deformation until failure. We observe by using Scanning Transmission Electron Microscopy the presence of cavities and the coexistence of homogeneous and fibrillar crazes.  Ultra Small Angle X-ray scattering experiments allows for describing the onset of damaging and the growth of crazes and for measuring the volume fractions of damages as well as their shapes and sizes at different stages during deformation. We propose that damages are initiated by the nucleation of cavities in the vicinity of pre-existing impurities. We then show that their initial growth after nucleation is blocked at a size of order 100 nm by the strain hardening in their immediate vicinity where deformation and stress are amplified. Increasing the stress further leads at some critical stress value to a new growth regime for a small fraction of crazes. We attribute this growth mechanism to homogeneous nucleation of new cavities just ahead of them. Failure of our samples is due to the propagation of a small number of crazes in a late stage of deformation and not to the accumulation of crazes and a coalescence process. The volume fractions of damage remain very low, of order of 10-4 at failure. The strain hardening behavior appears to be key for preventing an early failure of the material. 
Séminaire UMET
Lundi 20 Mai 2019 14:00
Caroline Genix
Laboratoire Charles Coulomb, Montpellier
  Small-angle scattering analysis of the structure of chains and filler in polymer nanocomposites
Séminaire UMET
Lundi 13 Mai 2019 14:00 - Bât C6, 202
Marine Lasbleis
Université de Nantes
  
Séminaire UMET
Mecredi 20 Mars 2019 14:00 - Bât C6, 202
Thomas P. Ferrand
Earthquake Research Institute, Univ. Tokyo, Japon
  Experimental confirmation of a spineloid transitional olivine polymorph using ultrafine-grained aggregates of Mg2GeO4.
Séminaire UMET
Mardi 12 Mars 2019 10:30 - Bât C6, 202
Luca Messina
Luca Messina
  AI-enhanced modeling of chemistry effects on microstructure evolution and characterization techniques “ / “Modélisation des effets chimiques sur la caractérisation de la microstructure, et possibles contributions de l’intelligence artificielle
Séminaire UMET
Lundi 11 Mars 2019 14:30 - ENSCL, salle Beaumaretz
Melissa Grunlan - Jaime Grunlan
Texas A&M University (College Station, TX – USA)
  Amphiphilic Silicones with Broad-Spectrum Anti-fouling Behavior - Super gas barrier and flame retardancy of clay-polymer nanocoatings
Séminaire UMET
Lundi 11 Mars 2019 14:00 - Bât C6, Salle 202
Nicolas Candau
EPFL, Lausanne
  Amélioration des priorités mécaniques de polyamides via inclusions aliphatiques et fibrillation in situ
Institutionnel
Mecredi 6 Mars 2019 9:00
  Visite Hcéres du laboratoire
Institutionnel
Mardi 5 Mars 2019 9:00
  Visite Hcéres du laboratoire
Institutionnel
Lundi 4 Mars 2019 12:00
  Visite Hcéres du laboratoire
Séminaire UMET
Jeudi 14 Février 2019 13:30 - Bât C6, Salle 202
Jin Long Liu
Northeastern University, Shenyang, China
   Control of recrystallization texture in silicon steels
Institutionnel
Vendredi 8 Février 2019 9:00 - Lilliad Amphi B
  Assemblée générale du laboratoire
Institutionnel
Mecredi 30 Janvier 2019 9:00 - Amphi B, Lilliad
  Visite Hcéres Institut Chevreul
Soutenance
Jeudi 24 Janvier 2019 10:00 - CERLA
Devadas Bhat Panemangalore soutient sa thèse
  Développement d'alliages à base de magnésium pour applications biomédicales
Soutenance HDR
Mecredi 16 Janvier 2019 10:15 - CERLA
Rajashekhara SHABADI
  Design, Development and Characterisation of Advanced Materials and Surfaces
Soutenance HDR
Vendredi 11 Janvier 2019 14:00 - ENSCL, salle 112
Ludovic THUINET
UMET
  Simulations atomiques et par champ de phase pour l’étude des microstructures dans les matériaux métalliques
Événement
Vendredi 11 Janvier 2019 9:00 - Polytech Amphi Migeon
  Journée des doctorants
 
UMET - Unité Matériaux et Transformations
CNRS UMR 8207
Université de Lille
Bâtiment C6
59655 Villeneuve d'Ascq
France
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