''Clinical Images: Milwaukee shoulder syndrome affecting the elbow''

Ornetti, Paul | Vernier, Nathalie | Fortunet, ClementineInternational audienc

A Mechanism Leading to γ′ Precipitates with {111} Facets and Unusual Orientation Relationships to the Matrix in γ–γ′ Nickel-Based Superalloys

International audienceCast-and-wrought heavily alloyed γ–γ′ nickel-based superalloys may exhibit large recovered grains inherited from the ingot conversion and characterized by a high density of close-to-coherent micrometric γ′ precipitates. In the AD730™ nickel-based superalloy, a previous work (Vernier et al. Scr Mater 153:10–13, 2018) highlighted a new interaction between such precipitates and a recrystallization front passing through. This interaction resulted in γ′ precipitates with a close-to-twin orientation relationship to their recrystallized host grain. Called T-type precipitates, they were revealed to be {111} bounded plate-like particles. The present paper aims to clarify the mechanism whereby such precipitates form. The formation of T-type precipitates actually is part of a more global mechanism which also produces γ′ precipitates slightly misoriented from their surrounding matrix (C-type precipitates) and of same size and morphology as T-type precipitates. Both T- and C-type precipitates display {111} facets and are evidenced in the AD730™, René65, and PER72 alloys, supporting the idea that the mechanism can more generally occur in all low-lattice-mismatch γ–γ′ nickel-based superalloys. Finally, a scenario is proposed: T/C-type precipitates form at the recrystallization front of grains sharing a 〈111〉 axis with the recovered grain they consume, and develop {111} facets and specific orientations which minimize the interfacial energy on both recrystallized and recovered sides

γ′ precipitates with a twin orientation relationship to their hosting grain in a γ-γ′ nickel-based superalloy

International audienceIn a polycrystalline γ-γ′ nickel-based superalloy, γ′ precipitates with a close-to-twin orientation relationship to their surrounding matrix (named T-type precipitates) are found in recrystallized grains located near specific unrecrystallized grains (named recovered grains). This type of γ/γ′ interface has not been reported in literature before. Inherited from the ingot conversion process, recovered grains are characterized by a high density of micrometric and close-to-coherent γ′ precipitates. Resulting from the interaction of the recrystallization front with the latter precipitates, the T-type precipitates appear to form onto the recrystallization front. The present paper details the crystallographic characteristics of the T-type precipitate

Immune Thrombocytopenic Purpura in Patients with COVID-19

We described three COVID-19-infected patients with profound immune thrombocytopenia causing haemorrhagic mucocutaneous complications. We conclude that an immune mechanism was responsible as common causes were excluded. Since corticoids were considered harmful in the circumstances, the patients were successfully treated with intravenous immunoglobulins without later relapse

Evolution des plages non recristallisées des billettes de superalliage base Nickel AD730 TM pendant une séquence de forgeage industriel

International audienceDans les billettes en superalliage base nickel AD730 TM , comme dans les autres nuances de la même famille (René 65, Udimet 720), la présence de plages non recristallisées forme des hétérogénéités qui contrastent singulièrement avec la matrice environnante. Ces plages se présentent sous la forme de longs grains restaurés aux caractéristiques microstructurales bien différentes de celles des grains équiaxes situés autour. En particulier, ces grains comportent une précipitation intragranulaire dense et cohérente avec la matrice qui rend leur recristallisation difficile au cours du forgeage

Nucleation mechanism of hetero-epitaxial recrystallization in wrought nickel-based superalloys

International audienc

Ni-based superalloy: crystalline orientation mapping and gamma - gamma’ phases discrimination with the iCHORD method

International audienc

Understanding the heteroepitaxial recrystallization in a polycrystalline superalloy during thermomechanical processing

International audienc

iCHORD-SI combination as an alternative to EDS-EBSD coupling for the characterization of γ-γ′ nickel-based superalloy microstructures

International audienceBecause they exhibit very similar diffraction patterns, the γ and γ' phases of nickel-based superalloys cannot be distinguished by the conventional EBSD technique alone. This paper presents an original method which discriminates those phases on an orientation map by exploiting their chemical differences. Performed with a Focused Ion Beam (FIB) microscope, the method is the combination of the ion CHanneling ORientation Determination technique (iCHORD) – recently developed by Langlois et al. [1] – with the chemical information obtained from Secondary Ion (SI) images. The performances of the method are compared to the EDS-EBSD coupling which also discriminates phases based on their chemical compositions. Applied filters, angular resolution, spatial resolution of the phase discrimination and acquisition time are discussed. It results that the iCHORD–SI combination offers an orientation map with an angular resolution slightly decreased compared to that of the EBSD technique, but with an interesting phase resolution (down to 150 nm) and within a reasonable acquisition time. Thus, the iCHORD–SI combination appears to be an interesting method for the crystallographic systems where phases are difficult to discriminate by the EBSD technique but present a significant chemical contrast

D’arbre en art. L'arboretum d'Amance

National audienceL’arboretum d’Amance est situé à 13 kilomètres à l’Est de Nancy, sur le territoire de la commune d’Amance. Il a été créé en 1900 par l’Ecole forestière avec deux objectifs : la connaissance du comportement d’espèces exotiques en lorraine et la mise en place d’un outil de reconnaissance dendrologique. Cet ouvrage, nouvellement mis en page et richement illustré, décrit à la fois l’histoire de cet arboretum, son évolution récente et son devenir