Download or read book Numerical Modeling of the Cold Spray Process written by Qing Song Zhu and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis involves numerical modeling of several cold spray processes in order to predict the gas flow as well as the particle conditions upon impacting on a substrate. Particle normal velocity was found to be the most important factor to improve the deposition efficiency and coating quality. Particle velocity was calculated with both Lagrangian and Eulerian approaches. The Lagrangian approach was used to investigate the effect of particle size and substrate geometry in a dilute particle flow. The shape and strength of the bow shock formed near the substrate for different geometries (such as concave, convex, and flat) were studied. Consequently, the particle normal velocities impacting on the substrates located at various stand-off distances were calculated. Furthermore, the numerical simulations were repeated with particles of various sizes as well as different types of feeding gas. The results were compared to obtain the optimum substrate location and the appropriate particle size for each feeding gas. The numerical results were validated against the experimental results for the majority of the process parameters including the gas Mach number and mean particle velocity. The Eulerian approach was also implemented to model dense particulate flows. It was found that a dense particulate flow could significantly decelerate the gas flow and consequently result in small particle velocity.
Download or read book Numerical and Experimental Characterization of the Cold Spray Process for Spraying Nano Particle Powders written by Abdulaziz Alhulaifi and published by . This book was released on 2011 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cold spray deposition process involves the acceleration of solid particles to high velocity by a carrier gas which is often supersonic, and the subsequent impingement of this high velocity, particle laden jet onto a substrate. In order for deposition to occur, i.e. in order for the solid particles to bond to the substrate, the impact velocity of the particles must be equal to or greater than some critical value. To determine an estimate of this critical velocity, the energy principle was used to predict a critical impact velocity based on material properties. It has been shown that during its interaction with the substrate, a particle should reach around 70% of its melting temperature to obtain good mechanical bonding. Using computational fluid dynamic models (CFD), a novel Aerodynamic Focusing Nozzle (AFN) using helium as the carrier gas, was developed and experimentally tested. The CFD models showed that a lighter gas such a helium must be used for the nanoparticles to reach critical velocity and penetrate the normal shockwave upstream of the substrate with sufficient inertia. A prototype AFN nozzle was fabricated using a rapid prototype machine and used to cold spray 300 nm diameter particles onto both aluminum and Kapton substrates at room temperature. Additional validation of the feasibility of the design was obtained through the deposition of a thin conductive copper layer of Kapton. This research focuses on the numerical modeling, as well as the construction and experimentation required for the development of the AFN for cold spraying nanoparticles. To characterize the results in a general way, a non-dimensionalization of all the factors involved was conducted and validated to determine the combination of cold spray process parameters required for the particle to reach the critical impact velocity and temperature.
Download or read book Thermal Spray Fundamentals written by Pierre L. Fauchais and published by Springer Science & Business Media. This book was released on 2014-01-24 with total page 1587 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides readers with the fundamentals necessary for understanding thermal spray technology. Coverage includes in-depth discussions of various thermal spray processes, feedstock materials, particle-jet interactions, and associated yet very critical topics: diagnostics, current and emerging applications, surface science, and pre and post-treatment. This book will serve as an invaluable resource as a textbook for graduate courses in the field and as an exhaustive reference for professionals involved in thermal spray technology.
Download or read book Numerical Modeling of Metal matrix Composite Coating in Cold Gas Dynamic Spray Process written by Rohan Chakrabarty and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Cold spray has demonstrated great promise in developing particle-reinforced metal matrix composites, which combine the high strength and toughness of metals with those of excellent wear resistance, corrosion resistance and chemical stability of ceramics. However, the understanding of mechanisms underlying the retention of ceramics in the coatings remains inadequate, making it difficult to develop optimizing strategies to manufacture composite coatings with better properties. Therefore, aiming to gain a deeper understanding of the ceramic retention behavior, the present thesis systematically investigated various key aspects through computational modeling, including the effect of varying the spraying parameters, the influence of substrate roughness and ceramic fracture/fragmentation on its retention behavior. The first part of the investigations focused on the effect of impact angles on the retention and embedding behavior of the ceramic particles. It was concluded that off-normal impact angle promoted the retention possibility of ceramics in the substrate by enhancing the contact strength, increasing the contact time and reducing the rebounding velocity. Moreover, it was also demonstrated that substrate material erosion increased as the impact angles decreased from normal.The second part involved simulations of the first-layer ceramic deposition involving ceramic particle and metal substrates. For soft substrates, crater depth was found to be the key factor in determining ceramic retention. While the ceramic retention was also greatly affected by the occurrence of jetting at the crater edges. Furthermore, it was demonstrated that substrate roughness could promote ceramic retention by mitigating jetting and increasing the crater depth.To account for the increase in flow stress at high strain-rates experienced during cold spray, a power law-based modification of Johnson-Cook model was proposed for the third investigation. Additionally, a strain gradient plasticity-based model was also proposed to accurately predict the cold sprayed particle’s shape consistent with the experimental observations in the literature.The final part of the investigation focussed on the dynamic behavior of micron-sized ceramic particles. Through a polycrystalline model, the fragmentation and retention of ceramic particles were studied concerning to grain size, impact velocity and grain boundary properties. It was demonstrated that grain size has an important role in determining the retention in the coating. Moreover, lower fragmentation and higher retention of ceramic particles were predicted during spraying a mixture of metal and ceramic particles onto a metal substrate. These studies offer new mechanistic insights into ceramic-metal interactions, and more generally, new knowledge and modeling tools to guide the design of better composite coatings through cold spray"--
Download or read book Cold Spray Technology written by Anatolii Papyrin and published by Elsevier. This book was released on 2006-10-04 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: The topic of this book is Cold Spray technology. Cold Spray is a process of applying coatings by exposing a metallic or dielectric substrate to a high velocity (300 to 1200 m/s) jet of small (1 to 50 μm) particles accelerated by a supersonic jet of compressed gas. This process is based on the selection of the combination of particle temperature, velocity, and size that allows spraying at the lowest temperature possible. In the Cold Spray process, powder particles are accelerated by the supersonic gas jet at a temperature that is always lower than the melting point of the material, resulting in coating formation from particles in the solid state. As a consequence, the deleterious effects of high-temperature oxidation, evaporation, melting, crystallization, residual stresses, gas release, and other common problems for traditional thermal spray methods are minimized or eliminated. This book is the first of its kind on the Cold Spray process. Cold Spray Technology covers a wide spectrum of various aspects of the Cold Spray technology, including gas-dynamics, physics of interaction of high-speed solid particles with a substrate as well as equipment, technologies, and applications. Cold Spray Technology includes the results of more than 20 years of original studies (1984-2005) conducted at the Institute of Theoretical and Applied Mechanics of the Siberian Division of the Russian Academy of Science, as well as the results of studies conducted at most of the research centres around the world. The authors' goal is threefold. The first goal is to explain basic principles and advantages of the Cold Spray process. The second goal is, to give practical information on technologies and equipment. The third goal is to present the current state of research and development in this field over the world. The book provides coverage and data that will be of interest for users of Cold Spray technology as well as for other coating experts. At the present time the Cold Spray method is recognized by world leading scientists and specialists. A wide spectrum of research is being conducted at many research centres and companies in many countries. New approach to spray coatings Results are exceptionally pure coatings Low spray temperature without degradation of powder and substrate materials High productivity, high deposition efficiency High operational safety because of absence of high temperature gas jets, radiation and explosive gases Excellent thermal and electrical conductivity Wide spectrum of applications because of important advantages of the process
Download or read book CFD Modeling and Simulation in Materials Processing written by Laurentiu Nastac and published by John Wiley & Sons. This book was released on 2012-05-09 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of a symposium sponsored by Association for Iron and Steel Technology and the Process Technology and Modeling Committee of the Extraction and Processing Division and the Solidification Committee of the Materials Processing and Manufacturing Division of TMS (The Minerals, Metals & Materials Society) Held during the TMS 2012 Annual Meeting & Exhibition Orlando, Florida, USA, March 11-15, 2012
Download or read book Development of a Numerical Model of Single Particle Impact with Adhesion for Simulation of the Cold Spray Process written by Paul Profizi and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the context of the Cold Spray process, a numerical model of a single particle impact is developed. The point of interest is the adhesion of the particle to the substrate, thus an adhesive interaction model is also created. The impact model uses the Smooth Particle Hydrodynamics and/or the Finite Elements methods, with a Johnson-Cook material law, commonly used for metals at high strain rates, which takes into account strain hardening, strain rate hardening and thermal softening. The adhesive interaction is a Griffith and Dugdale-Barenblatt cohesive model with energy dissipation and a limit on the cohesive stress. Using this model it is shown that in the case of fast dynamics and deformable bodies, not only the adhesion parameters but also the type of model has an influence on the results. The adhesion model is also, contrary to previous works, linked with an actual physical mechanism known to induce adhesion in Cold Spray: a shear stress instability at the interface. This is done by adding an activation criterion to the cohesive model. This criterion is defined as a local drop in yield strength on either element in contact. Only when this criterion is locally met are the cohesive stresses applied and cohesive energy dissipated. The result is the apparition of a critical velocity, under which adhesion cannot occur due to either not enough initial kinetic energy to create an instability at the interface, or not enough adhesive surface created to keep the particle from rebounding. For the model to localize and undergo shear banding/shear instability, a damage value is added to the material law. An erosion criterion is then implemented in the cohesive model to remove the cohesive stresses from highly damaged parts of the adhesive surface. This results at high impact speeds in a maximal velocity above which the interfacial material is too damaged to sustain adhesion and prevent the particle from rebounding. A deposition behavior similar to the Cold Spray process is then observed, with a range of low velocities without any adhesion of the particle, then a critical speed initiating a velocity range of adhesion of the particle, and finally a maximum speed above which the interface is too damaged to sustain the adhesion. A set of experimental observations is also carried out to better understand the actual microstructural dynamics and changes at the interface of 1 mm copper particles impacted on copper. The results are compared to simulations and the use of the macroscopic Johnson-Cook law at a microscopic level is validated.
Download or read book Cold Spray Coatings written by Pasquale Cavaliere and published by Springer. This book was released on 2017-11-08 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book combines the contributions of experts in the field to describe the behavior of various materials, micromechanisms involved during processing, and the optimization of cold-spray technology. It spans production, characterization, and applications including wear resistance, fatigue, life improvement, thermal barriers, crack repair, and biological applications. Cold spray is an innovative coating technology based on the kinetic energy gained by particles sprayed at very high pressures. While the technique was developed in the 1990s, industrial and scientific interest in this technology has grown vastly in the last ten years. Recently, many interesting applications have been associated with cold-sprayed coatings, including wear resistance, fatigue life improvement, thermal barriers, biological applications, and crack repair. However, many fundamental aspects require clarification and description.
Download or read book Development of a Numerical Model of Single Particle Impact with Adhesion for Simulation of the Cold Spray Process written by Paul Profizi and published by . This book was released on 2019 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the context of the Cold Spray process, a numerical model of a single particle impact is developed. The point of interest is the adhesion of the particle to the substrate, thus an adhesive interaction model is also created. The impact model uses the Smooth Particle Hydrodynamics and/or the Finite Elements methods, with a Johnson-Cook material law, commonly used for metals at high strain rates, which takes into account strain hardening, strain rate hardening and thermal softening. The adhesive interaction is a Griffith and Dugdale-Barenblatt cohesive model with energy dissipation and a limit on the cohesive stress. Using this model it is shown that in the case of fast dynamics and deformable bodies, not only the adhesion parameters but also the type of model has an influence on the results. The adhesion model is also, contrary to previous works, linked with an actual physical mechanism known to induce adhesion in Cold Spray: a shear stress instability at the interface. This is done by adding an activation criterion to the cohesive model. This criterion is defined as a local drop in yield strength on either element in contact. Only when this criterion is locally met are the cohesive stresses applied and cohesive energy dissipated. The result is the apparition of a critical velocity, under which adhesion cannot occur due to either not enough initial kinetic energy to create an instability at the interface, or not enough adhesive surface created to keep the particle from rebounding. For the model to localize and undergo shear banding/shear instability, a damage value is added to the material law. An erosion criterion is then implemented in the cohesive model to remove the cohesive stresses from highly damaged parts of the adhesive surface. This results at high impact speeds in a maximal velocity above which the interfacial material is too damaged to sustain adhesion and prevent the particle from rebounding. A deposition behavior similar to the Cold Spray process is then observed, with a range of low velocities without any adhesion of the particle, then a critical speed initiating a velocity range of adhesion of the particle, and finally a maximum speed above which the interface is too damaged to sustain the adhesion. A set of experimental observations is also carried out to better understand the actual microstructural dynamics and changes at the interface of 1 mm copper particles impacted on copper. The results are compared to simulations and the use of the macroscopic Johnson-Cook law at a microscopic level is validated.
Download or read book Thermal Spray 2006 written by Basil Richard Marple and published by ASM International. This book was released on 2006-01-01 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Cold Spray Materials Deposition Process written by and published by Elsevier. This book was released on 2007-09-21 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cold spray process produces dense, low oxide coatings which can be used in such diverse applications as corrosion control and metals repair. It has emerged as an important alternative to thermal spray coating techniques in certain areas. This pioneering book reviews both the fundamentals of the process and how it can best be applied in practice. The first part of the book discusses the development of the process together with its advantages and disadvantages in comparison with thermal spray coating techniques. Part two reviews key process parameters such as powders, nozzle design, particle temperature and velocity, and particle/substrate interaction. It also describes portable and stationary cold spray systems. The final part of the book discusses how the cold spray process can be applied in such areas as improved wear, corrosion protection, electromagnetic interference shielding and repair of damaged components. The cold spray materials deposition process is a standard reference on this important process and its industrial applications. Examines the fundamentals of the cold spraying process Assesses how the technique can best be applied in practice Describes portable and stationary cold spray systems
Download or read book Modern Cold Spray written by Julio Villafuerte and published by Springer. This book was released on 2015-08-24 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the current state of the art of the novel cold spray process. Cold spray is a solid state metal consolidation process, which allows engineers to tailor surface and shape properties by optimizing process parameters, powder characteristics and substrate conditions for a wide variety of applications that are difficult or impossible by other techniques. Readers will benefit from this book's coverage of the commercial evolution of cold spray since the 1980's and will gain a practical understanding of what the technology has to offer.
Download or read book CFD Modeling and Simulation in Materials Processing 2016 written by Laurentiu Nastac and published by Springer. This book was released on 2017-08-31 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Special Issue Recent Advances in Modeling and Numerical Simulation of Thermal Spray Processes written by Joachim Heberlein and published by . This book was released on 2009 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulation of Cold Spray Particle Deposition Process written by Jing Xie and published by . This book was released on 2014 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cold spray is a rapidly developing coating technology for depositing materials in the solid state. The cold spray particle deposition process was simulated by modeling the high velocity impacts of spherical particles onto a flat substrate under various conditions. We, for the first time, proposed the Couple Eulerian Lagrangian (CEL) numerical approach to solve the high strain rate deformation problem. The capability of the CEL numerical approach in modeling the Cold Spray deposition process was verified through a systematic parameter study, including impact velocity, initial particle temperature, friction coefficient and materials combination. The simulation results by using the CEL numerical approach agree with the experimental results published in the literature. Comparing with other numerical approaches, which are Lagrangian, ALE and SPH, the CEL analyses are generally more accurate and more robust in higher deformation regimes. Besides simulating the single particle impact problem, we also extended our study into the simulation of multiple impacts. A FCC-like particles arrangement model that inspired by the crystal structure was built to investigate the porosity rate and residual stress of deposited particles under various conditions. We observed not only the 3D profiles of voids, but also their distributions and developments during different procedures. Higher impact velocity and higher initial temperature of particles are both of benefit to produce a denser cold spray coating. The compressive residual stresses existed in the interface between the particle and substrate is mainly caused by the large and fast plastic deformation. Another simplified model for multiple impacts was created for the simulation of surface erosion. A severe surface erosion is the result of a high impact velocity, a high friction coefficient and a low contact angle. Two element failure models suitable for high-strain-rate dynamic problems were introduced in this study. For a ductile material as Copper, it followed two fracture modes in our study, which are tensile failure mode and shear failure mode. The former one mainly occurred beneath the substrate surface and the periphery of substrate craters, nevertheless the latter one was found predominately at the surface of craters. Four steps were found during the propagation of crack: void formation; crack formation; crack growth; coalescence and failure. A simple criterion equation was derived based on the simulation results for predicting the initiation of damage, which the erosion velocity v_{ero} is a function of contact angle and erosion velocity for normal impact v_{pi/2}. The equivalent plastic strain could also be a parameter for identifying the onset of damage, identified as being 1.042 for Copper in our study.
Download or read book Advanced Surface Coating Techniques for Modern Industrial Applications written by Roy, Supriyo and published by IGI Global. This book was released on 2020-09-18 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: In engineering, there are often situations in which the material of the main component is unable to sustain long life or protect itself from adverse operating environments. Moreover, in some cases, different material properties such as anti-friction and wear, anti-corrosive, thermal resistive, super hydrophobic, etc. are required as per the operating conditions. If those bulk components are made of such materials and possess those properties, the cost will be very high. In such cases, a practical solution is surface coating, which serves as a protective barrier to the bulk material from the adverse environment. In the last decade, with enormous effort, researchers and scientists have developed suitable materials to overcome those unfavorable operating conditions, and they have used advanced deposition techniques to enhance the adhesion and surface texturing of the coatings. Advanced Surface Coating Techniques for Modern Industrial Applications is a highly sought reference source that compiles the recent research trends in these new and emerging surface coating materials, deposition techniques, properties of coated materials, and their applications in various engineering and industrial fields. The book particularly focuses on 1) coating materials including anti-corrosive materials and nanomaterials, 2) coating methods including thermal spray and electroless disposition, and 3) applications such as surface engineering and thin film application. The book is ideal for engineers, scientists, researchers, academicians, and students working in fields like material science, mechanical engineering, tribology, chemical and corrosion science, bio-medical engineering, biomaterials, and aerospace engineering.
Download or read book Advanced Surface Enhancement written by Sho Itoh and published by Springer Nature. This book was released on 2019-08-30 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the proceedings of the first INCASE conference, organised by ARTC at A*STAR, Singapore. It provides a comprehensive review of recent advances in surface enhancement processes and strategies employed to assess their impact on materials properties and performance. As cyber-physical systems are becoming more and more relevant in manufacturing, it focuses on assessing the readiness of current technologies for future transformations, such as Industry 4.0, identifying the opportunities and challenges, and exploring ways to address them. Written by researchers, practising engineering and industry experts, the book bridges the gap between research and manufacturing, promoting technology adoption in industry and innovative ideas to prepare it for the future.
