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Статті в журналах з теми "Projection dynamique à froid":
Wang, Yingying, Bernard Normand, Nicolas Mary, Min Yu, and Hanlin Yao. "Contribution à l'optimisation de la résistance à la corrosion de revêtements d'alliage d'aluminium élaborés par projection dynamique à froid (cold spray)." Annales de chimie Science des Matériaux 38, no. 1-2 (June 28, 2013): 1–12. http://dx.doi.org/10.3166/acsm.38.1-12.
Leroy, F., C. Counhaye, P. Aubry, L. Chefneux, and M. Remy. "Simulation dynamique des structures de contrôle de l’épaisseur en laminage à froid." Revue de Métallurgie 97, no. 6 (June 2000): 789–98. http://dx.doi.org/10.1051/metal/200097060789.
Dessons, Marie. "Projection et dynamique transférentielle dans une cure d’enfant." Psychologie clinique et projective 33, no. 1 (June 30, 2023): 75–92. http://dx.doi.org/10.3917/pcp.033.0075.
Villeneuve, Paul Y., and D. Michael Ray. "Croissance allométrique et dynamique spatiale." Cahiers de géographie du Québec 19, no. 46 (April 12, 2005): 5–15. http://dx.doi.org/10.7202/021245ar.
Lafortune, Manuel, Louise Filion, and Bernard Hétu. "Dynamique d’un front forestier sur un talus d’éboulis actif en climat tempéré froid (Gaspésie, Québec)." Géographie physique et Quaternaire 51, no. 1 (October 2, 2002): 67–80. http://dx.doi.org/10.7202/004840ar.
Gras, Laurent. "Show sportif et buffet froid. Interactions sportives et sociales entre détenus et joueurs extérieurs." Criminologie 36, no. 2 (April 5, 2004): 105–25. http://dx.doi.org/10.7202/007869ar.
Boleda, Mario, and Enrique Tandeter. "Dynamique démographique dans les Andes centro-méridionales." Articles 31, no. 2 (April 15, 2003): 215–48. http://dx.doi.org/10.7202/000666ar.
Tankeu, Aurel T., and Christel Tran. "Fatigue chronique: quand suspecter une maladie héréditaire du métabolisme?" Praxis 111, no. 1 (January 2022): 38–43. http://dx.doi.org/10.1024/1661-8157/a003772.
El Baroudi, Adil, Fulgence Razafimahery, and Lalaonirina Rakotomanana-Ravelonarivo. "Analyse dynamique par projection modale d’un modèle 2D du système couplé crâne-LCR-cerveau." Mécanique & Industries 11, no. 3-4 (May 2010): 235–43. http://dx.doi.org/10.1051/meca/2010061.
Asenjo González, María. "Las tierras de baldío en el concejo de Soria, a fines de la Edad Media." Anuario de Estudios Medievales 20, no. 1 (April 2, 2020): 389. http://dx.doi.org/10.3989/aem.1990.v20.1156.
Дисертації з теми "Projection dynamique à froid":
Raletz, François. "Contribution au développement d'un procédé de projection dynamique à froid (P. D. F. ) pour la réalisation de dépôts de nickel." Limoges, 2005. http://aurore.unilim.fr/theses/nxfile/default/e369083a-8453-4a2d-bb2d-08ac15a75238/blobholder:0/2005LIMO0024.pdf.
This Ph. D. Work deals with the study of the formation of cold sprayed nickel coatings. In this process, powder grains are introduced in a supersonic gas stream. For each material, beyond a specific velocity called the critical velocity, particles start to bind onto the substrate. The results of this study show that, for a powder batch, the deposition efficiency is only linked to the rate of particles that can exceed the critical velocity. An increase of the particles mean velocity (obtained by an increase of the propellant gas temperature, pressure or by the use of helium) raises the deposition efficiency. The particle velocity has been calculated with two methods (the one-dimensional isentropic theory and a 2D model). Comparison of the results with measured velocity shows that the mathematical models are consistent and accurate. Two techniques for the critical velocity determination have been developed. Values obtain with them appear to be consistent with those found in the literature. Contrary to deposition efficiency, the porosity level and hardness of the coatings are not linked to the impact velocity. The addition of a particle heater to the spraying system allows to increase slightly the deposition efficiency. Using a well adapted nozzle design can also improve it significantly
Rolland, Gilles. "Élaboration et étude de l'endommagement de dépôts composites obtenus par projection dynamique par gaz froid ("cold spray") : application aux contacts électriques." Phd thesis, École Nationale Supérieure des Mines de Paris, 2010. http://pastel.archives-ouvertes.fr/pastel-00584319.
Kergourlay, Emmanuelle. "Apatites nanocristallines biomimétiques carbonatées pour applications médicales : de la synthèse des poudres aux revêtements par projection dynamique à froid (Cold Spray)." Thesis, Toulouse, INPT, 2016. http://www.theses.fr/2016INPT0005.
Atmospheric plasma sprayed (APS) coatings of hydroxyapatite (HA) are considered as standard coatings in the field of orthopedic implants. However, some studies have shown that these coatings contained secondary phases resulting from the decomposition of HA during the spraying process, which could potentially limit the lifetime of implants. Moreover, nosocomial infections have been reported a few years after surgery. Although HA has osteoconductive properties, it has a different chemical composition and crystal characteristics from those of bone mineral (non-stoichiometric; carbonated and poorly crystallized). Biomimetic nanocrystralline apatites, on the contrary, offer the advantage to possess a surface hydrated layer analogous to that identified in bone mineral which can be functionalized. A carbonated nanocrystalline apatite similar to bone mineral "BNAc" and a silver doped biomimetic apatite "AgBNAc" were synthesized for this study, which could potentially accelerate osseointegration of implants (BNAc and AgBNAc) and prevent nosocomial infections (AgBNAc). In order to preserve the physicochemical characteristics of these powders, thermically unstable and very reactive, an industrial low temperature deposition process was selected: the Cold Spray. In contrast with other thermal spray processes, it has the advantage of spraying unmelted particles through a supersonic gas jet. Biomimetic apatite coatings with physicochemical properties similar to the powders were obtained by Cold Spray. Preliminary tests of biocompatibility and adhesion were also carried out on these coatings : the Cold Spray process seems to be a promising method preserving the characteristics of biomimetic nanocrystalline apatites and offering the possibility to produce industrial coatings with a potential to improve implants osseointegration and resistance to infections
Blochet, Quentin. "Influence de la rugosité de surface du substrat sur l'adhérence de revêtements à base d'aluminium élaborés par projection dynamique par gaz froid ("cold spray")." Thesis, Paris, ENMP, 2015. http://www.theses.fr/2015ENMP0025/document.
The cold spray process is based on high-speed spraying of a powder onto a substrate. The formation of a more or less dense coating depends on sprayed particle adhesion and coating build-up. The repair of metallic or composite aircraft / aerospace components is a recent application of cold spraying. The particle-substrate bond strength is due to various mechanisms, including mechanical anchoring. Substrate material hardness and surface topography governs the degree of mechanical anchoring. This thesis study is centered on the influence of these two contributions. Pure metallic and composite systems with different mechanical properties are selected. Particle deposition onto rough surfaces is investigated through the development of pure aluminium coating of harder aluminum alloy substrates. Plastic deformation and build-up mechanisms are studied for Al-SiC coatings onto ductile substrate. All the coatings resulted from an optimization stage where process parameters and materials properties are considered (gas temperature, gas pressure, particle size). Particle impact conditions are also determined by particle speed experimental measurements (using a DPV 2000 system). Substrate temperatures are determined using thermocouple and particle temperatures are studied by numerical simulation. Mechanical anchoring of particles is investigated by cross-section observation of the coating-substrate interface. Hardness gradient is also quantified. An analysis of sand-blasted surfaces morphology is performed to correlate particle size and roughness parameters. A model of particle impact is established from a finite element analysis of interface plastic deformation as a function of surface topography. Lastly, dynamic adhesion testing using a laser shock (LASAT®) are undertaken to study the potential role of interface roughness on the fracture thresholds in the light of a numerical analysis
Bunel, Margaux. "Influence du traitement thermique des poudres sur le dépôt sur projection dynamique par gaz froid (« cold spray ») d’alliage d’aluminium 2024 pour la fabrication additive." Thesis, Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLM051.
Cold spray is a process where powder particles are sprayed at a high speed onto a substrate. From deformation the powder particles adhere to the substrate, which result in deposition build-up. The cold sprayed coatings show high mechanical properties, are very dense, can be thick and have a high deposition efficiency, which makes cold spray an ideal process for additive manufacturing. However, deposition efficiency for aluminum alloys such as those commonly used in different industrial sectors, are insufficient for additive manufacturing to be economically viable. In this study, a heat treatment of the powder is carried out in order to modify the properties of the powder particles to improve the deposition efficiency. The influence of the type of cold spray facilities and of spraying parameters was studied from the measurement of the particle velocity (DPV2000) and from assessing the properties of the various coatings. The coatings made of the heat treated powders compared with those made of untreated powders using similar conditions for both were used to show the influence of the modification of the particles. Additive manufacturing requires the understanding of how powder particle build-up to achieve given shapes. A model of deposition, at a macroscopic scale, based on experimental data was developed to predict the shape of the deposit. The results of these simulations were compared to experimental deposits to check thickness, shape and the surface state
Leger, Pierre-Emmanuel. "Rôle de la microstructure sur les mécanismes de corrosion marine d’un dépôt à base d’aluminium élaboré par projection dynamique par gaz froid (« cold spray »)." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEM005.
Cold spray process is based on spraying particles carried by a gas at a supersonic speed onto a substrate. Particle deformation during impact with the substrate creates a coating. This spraying process can retain particle microstructure and produce very dense coating. This property is crucial for anticorrosion applications. The aim of this work is to understand the effect of cold spray aluminum coating microstructure on marine corrosion mechanisms. To achieve this goal, several aluminum powders (including pure aluminum, aluminum alloys and mixtures with alumina) are sprayed onto a steel substrate. Coating microstructure is studied down to a nanoscale (TEM). The coating-substrate bond strength is determined using pull-off testing. From a thorough microstructure study, various mechanisms are proposed to explain multiscale porosity formation in coatings. A numerical study using finite elements modeling complements this microstructure analysis. From particle speed (DPV-2000) and temperature (thermal camera) measurements during impact, new material models are optimized to model aluminum and alumina behavior at particle impact. Moreover, corrosion tests are conducted (including immersion and salt spray tests). The study of corroded coating microstructures is used to identify corrosion mechanisms which occur in the coating. A relationship between coating porosity and its corrosion behavior is particularly brought into light. Finally, a first approach to a technological transfer of this process to an industrial application is proposed
Delloro, Francesco. "Méthodes morphologique et par éléments finis combinées pour une nouvelle approche de la modélisation 3D du dépôt par projection dynamique par gaz froid (« cold spray »)." Thesis, Paris, ENMP, 2015. http://www.theses.fr/2015ENMP0017/document.
This study on the cold spray process aimed at achieving an original coating build-up model, capable of predicting the resulting microstructure as a function of powder morphology and process parameters. The work focused on three main interrelated subjects: 3D powder characterization, simulation of individual impacts on a flat substrate by the finite element method and deposition build-up modeling.An innovative method based on microtomographical observations was used for 3D characterization of the powder. Image analysis allowed to separate single powder particles and to gather them into a 3D collection containing approximatively 18 000 objects. Their size and shape were quantitatively measured. A cluster analysis method (K-means) was then applied to this data set to divide the particles into 7 classes based on their shape.The second main research topic consisted in performing particle impact simulations on a flat substrate by the finite element method (using the commercial software Abaqus). The use of dedicated meshing tools allowed to simulate the impact of real particles, as observed by microtomography. Scripting techniques were used to carry out a large number of these simulations but, due to limited robustness of the procedure, only few of them were successfully conducted.The third research area focused on the development of a deposition build-up model (in 2D to allow a simpler implementation). Data from finite element results were interpolated and used in an iterative simulation, where impacting particles were deposited one by one. Different approaches were tested but the development of the model could not be completed in the framework of this thesis.Model validation could be performed on finite element simulations. The two kinds of splats (Ta on Cu and Ta on Ta) were considered separately. Concerning the first, direct microtomographical imaging could be applied, due to the heterogeneity of materials. Splats were observed, individually separated and gathered in a 3D collection as done before with powder particles. Simulated and observed splats could then be compared on a statistical basis. No particular discrepancy was observed, confirming the impact simulation method used. The second kind of splats (Ta on Ta) was complicated by the homogeneity of the materials, preventing the use of microtomography. The deposition (before spraying) of a contrast layer between Ta substrate and Ta particle was tried by different techniques. The only method giving exploitable results was the chemical vapor deposition of a Fe layer onto the powder particles. However, the small number of adherent particles and the weak contrast obtained in the images prevented the use of the methods already applied to powder particles and Ta splats onto Cu.The optimization of powder granulometry and shape (towards a specific application) is one of the main expected applications of the deposition build-up model, together with the simulation of composite powders (typically, metal and oxide). The involvement of phase transformation phenomena into the model could extend its application to the whole family of thermal spray processes (plasma, HVOF, etc.) or to other additive manufacturing techniques. In general, the philosophy behind our modeling approach could be applied to every manufacturing/coating technique where the supply material is in powder form and undergoes a certain transformation during the process. Finally, the coupling of such a model with homogenization techniques would allow the prediction of macroscopic properties depending on deposit microstructure (e.g. thermal or electrical conductivity)
Weiller, Sébastien. "Etude de la relation entre porosité et étanchéité à l'ultra-vide de dépôts à base d'aluminium obtenus par projection dynamique par gaz froid ("cold spray")." Thesis, Université Paris sciences et lettres, 2021. http://www.theses.fr/2021UPSLM004.
Cold Spray is a thermal spray process, a key advantage of which is its capability to achieve highly-dense coatings. The practical objective of the study is to fully exploit this asset to obtain a metallic coating which exhibit gas-tightness in ultra-high vacuum conditions as requested for the targeted application. The thesis work consists in studying cold spray conditions to result in suitable properties. The study will focus on porosity formation mechanisms when spraying. A major objective is to determine a critical size for porosity above which gas-tightness no more meets the required specifications for the application. For this, relevant characteristics of pores (size, distribution, shape, ... ) will be assessed. More basically, the work aims to correlate, including using numerical simulation, these characteristics with the previously-mentioned formation mechanisms as a function of spraying conditions. The influence of the substrate (a metal or a polymer) onporosity will be studied in particular, through the study of modifications in the coating build-up. Coating-substrate bond strength will be determined, based on the study of adhesion mechanisms since an influence of these on gas-tightness can be expected
Bortolussi, Vincent. "Etude expérimentale et numérique de la conductivité de revêtements composites métal-polymère déposés par projection dynamique par gaz froid sur substrat composite à matrice organique." Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEM075/document.
The Cold Spray process allows to manufacture metallic coatings onto Carbon Fiber-Reinforced Composite (CFRP). This process relies on the spraying of high-velocity powder particles to result in high deformation and build up to form a dense coating. However, forming a coating made of copper particles onto a substrate containing carbon fibers was achieved out only by mixing metallic powder with a polymer powder. Although the polymer allow to build up the coating onto CFRP, it is highly electrically insulating. It would therefore decrease the electrical conductivity of the coating drastically. Investigations were carried out on the influence of the coatings microstructure on electrical conductivity. Various copper powders, with different morphologies, granulometry and oxygen contents were mixed with PEEK powder, i.e. a thermoplastic polymer. Cold spray of these powders leads to homogeneous coatings onto CFRP. The characteristics of these coatings were studied as a function of the influence of powder characteristics and spraying parameters. The deformation of the PEEK was also investigated as it governed the build up of the coating. Mechanical testing of PEEK samples and in-situ spraying measurements were performed to feed impact simulations. Then, simulated and experimental impact morphologies of copper particles onto PEEK were compared. The PEEK behavior under impact also prevented sound contacts between copper particles, which decreased the coatings electrical conductivity significantly. A morphological model of the microstructure of the coating was developed to reproduce microstructures in 3D numerically. It allows to investigate numerically the influence of the copper phase morphology on coating conductivity. This conductivity was measured experimentally for various starting copper powders. A carefully selected blend of copper and PEEK powders and optimized spraying parameters lead to homogeneous coatings onto CFRP with an acceptable electrical conductivity but still below bulk copper conductivity
Gojon, Sébastien. "Etude sur l’élaboration et la caractérisation de revêtements en alliages d’aluminium et de magnésium par projection dynamique à froid pour la réparation de pièces aéronautiques." Thesis, Belfort-Montbéliard, 2015. http://www.theses.fr/2015BELF0272/document.
The repair of light alloy parts is a major issue in aeronautics. Aluminum alloy and magnesium alloy are widely used in aircraft parts, especially for high value-added components. Their use combined to optimizing design allows to have satisfactory products meeting mass, cost and performance requirements. However, like any other life-limited components, various damages can occur not only during handling procedure but also while operating. Rectification solutions exist but do not always comply with requirements. These limitations entail high scrap rates among high value-added parts.The various advantages of the cold spray process make it an ideal candidate for suitable coatings for light alloy aircraft components as protective, retouching or repair methods. The aim is to rebuild the damaged part by a coating whose characteristics are closest to those of primary materials. This thesis proposes to optimize different cold spray parameters for several substrate-coating pairs combining different aluminum alloys, magnesium alloys and aluminum alloy-based metal matrix composites.The first step was to optimize the main parameters of cold spray process to prevent clogging phenomenon that may occur in the expansion part of the nozzle. It decreases particle kinetics and promotes porous coating. Then, adhesion optimization of substrate-coating couples was investigated. The substrate surface preparation is a key factor on coating adhesion, where the mechanical anchoring appears essential. Finally, an innovative study was conducted to develop a method to cover locally surface defects. Offline programming trajectories were used to fill up two kinds of pre-machined defaults on aluminum alloy blocks. Results are in good agreement with spray time savings and defect free coatings after machining
Частини книг з теми "Projection dynamique à froid":
FIGUEIREDO, Cristina. "« Éteri ». Liens de parenté, humeurs et sentiments chez les Touaregs Kel Adagh." In Les butoirs de la pensée, 43–60. Editions des archives contemporaines, 2021. http://dx.doi.org/10.17184/eac.5461.