bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Cold Spray Deposition of a Titanium Coating on the Fatigue Behaviour of a Titanium Alloy
Authors: Price T.S. , Shipway P.H. , McCartney D.G. 
Published: September 2022

Abstract
The deposition of titanium on a titanium alloy substrate is being examined for potential use as a surface treatment for medical prostheses. A Ti6Al4V alloy was coated with pure titanium by cold gas dynamic spraying (CGDS). Coatings were deposited onto samples with two different surface preparation methods (as-received and grit blasted). The fatigue life of the as-received and grit blasted materials, both before and following coating, was measured with a rotating-bend fatigue rig. An 18% reduction in fatigue life was observed following the application of the coating to the as-received substrate, but no significant reduction was observed on its application to the grit blasted substrate. The reduction in fatigue life has been related to the substrate-coating interface properties and residual stress states.
Formation of Fe-Al Intermetallic Compound Coating Through Cold Spraying
Authors: Wang H.-T. , Li C.-J. , Yang G.-J. , Li C.-X. 
Published: September 2022

Abstract
Intermetallic materials have excellent high temperature oxidation resistance and erosion, cavitation resistances and are promising coating materials with many potential industrial applications. In this study, the formation of Fe-Al intermetallic compound-based coating was performed by cold spraying assisted by a post-annealing treatment. Fe-Al alloy composite powder containing 20wt% WC-Co was produced by ball milling process. Nano-structured Fe-Al alloy coating was deposited through cold spraying. The coating was annealed at different temperatures. The microstructure of the coating was characterized by scanning electron microscopy, optical microscopy and x-ray diffraction analysis. It was found that the microstructure of the as-sprayed coating depended significantly on the microstructure of the powder. A Fe-Al intermetallic phase was formed during the annealing at a temperature higher than 500°C. Moreover, grain growth occurred with the increase of the annealing temperature. The results showed that the microhardness of the as-sprayed coating reached 600HV and more. The effect of the annealing treatment on the coating microstructure and hardness was examined.
Cold Spraying – Potential and New Application Ideas
Authors: Kroemmer W. , Heinrich P. 
Published: September 2022

Abstract
Spurred on by the initial success of cold spray applications, a wide range of industrial sectors have since shown a tremendous interest in the youngest of the thermal spray processes. The forerunner, oxide-free copper coatings, paved the way for a variety of materials to be successfully sprayed at the Linde Technology Centre in Munich. At the same time, the hardware for cold spraying also underwent rapid development. This now means that new materials can be processed with the highest efficiency and quality possible, using lower-cost nitrogen rather than helium which is decidedly more expensive.
Depositing Titanium Alloy Additive Features to Forgings and Extrusions Using the Cold Spray Process
Authors: Blose R.E. , Walker B.H. , Walker R.M. , Froes S.H. 
Published: September 2022

Abstract
Development of new low-cost methods for spray forming Titanium alloys is critical for many industries. Direct fabrication technologies would have an impact on many industries because of the potential for quick manufacture of parts or additive features with minimal waste. For example, in the aerospace industry the buy to fly ratios can vary from 1.5:1 for turbine blades to over 22:1 for structural members. The buy to fly ratio is the mass of material that is require to machine a part compared to the mass of material in the finished part. For compressor and ring sections, the ratio is approximately 12:1. For this family of parts, an analysis by Pratt & Whitney indicated that the buy to fly ratio could be reduced by 41% to 7:1 if cold spray could be implemented to deposit isogrids, structural ribbing, bosses, and flanges reducing the material, machining, and post processing required for the final part. This paper summarizes the results of experiments conducted in Phase I of a National Science Foundation grant to spray form Titanium alloy using the cold spray process. This paper further describes the studies performed to date in Phase II and the techniques used to decrease the porosity of the as-sprayed coating from 18% to between 2% and 5% and the post processing methods employed to further consolidate the coating and restore the as-sprayed material to near wrought properties.
SIMAT Application for Aerospace Corrosion Protection and Structural Repair
Authors: Boro Djordjevic B. , Maev R. Gr. 
Published: September 2022

Abstract
Supersonically Induced Mechanical Alloy Technology (SIMAT™) also known as gas-dynamic spraying is under development for corrosion protection and material repair for aluminum airframe structures. This technology enables material powder consolidation that is not possible using other spray technologies. Similar to cold spray but based on compact spray head with nozzle powder feed, SIMAT™ is a low temperature process and does not create the high-temperature environment that affects both the substrate (especially thermally non-stable substrates) and the deposited coating. The emerging SIMAT™ technology, now in development, has the potential for coating, repairing, joining and rapid prototyping powder based materials. The SIMAT™ method adds new flexibility to powder material deposition producing thin to very thick deposits of various metals and metal-ceramic mixtures based on a cold spray particle kinetic approach inducing impact fusion. Solid particles in the size range of 10 to 100 microns are accelerated into a supersonic stream (ranging from 300 to 1200 m/s) using compressed air. These high velocity cold particles are projected on to a work piece. There is no heat discharge in the spray device itself, thus the powder material retains original characteristics. This spraying technique can generate a wide range of deposited layers with thickness ranging from tens of microns up to as much as centimeters. The process extends beyond the concept of “coatings” and includes the capability for in-situ material build-up and consolidation to three-dimensional structures and joining of the components. The deposition and consolidation can be performed from a range of hybrid powders consisting of metals, alloys, ceramics and glasses. Sample tests demonstrate examples of the process on typical aircraft components for new or restored corrosion protection and demonstrate damage repair for potential service life extension of the aircraft structure.
Numerical Simulation of the Cold Gas Dynamic Spray Process
Authors: Karimi M. , Fartaj A. , Rankin G.W. , Vanderzwet D. , Villafuerte J. , Birtch W. 
Published: September 2022

Abstract
A computational fluid dynamic (CFD) model of the cold gas dynamic spray process is presented. The gas dynamic flow field and particle trajectories within an oval shaped supersonic nozzle as well as in the immediate surroundings of the nozzle exit, before and after the impact with the target plane, are simulated. Predicted nozzle wall pressure values compare well with experiment. In addition, predicted particle velocity results at the nozzle exit are in qualitative agreement with those obtained using a side-scatter laser Doppler anemometer (LDA.) Details of the pattern of particle release into the surroundings are visualized in a convenient manner.
Low Pressure Gas Dynamic Spray: Shear Localization during Particle Shock Consolidation
Authors: Maev R. Gr. , Leshchinsky Ev. 
Published: September 2022

Abstract
Gas Dynamic Spray (GDS) is a high rate, direct material-deposition process that utilizes the kinetic energy of particles sprayed at supersonic velocities to cause bonding through the particle plastic deformation on impact. GDS seems to be similar to the powder shock consolidation process, which is governed by dynamic regimes of granular material deformation under impulse loading. These regimes are characterized by adiabatic shear band (ASB) formation. This paper describes the preliminary analysis of ASB formation during GDS on the basis of a combination of the Johnson-Cook and shock wave consolidation models. The dependence of the ASB width on different parameters, including initial powder porosity, average impact stress, shear strain, initial temperature, and contact time was determined. The ASB width was found to vary in the range of 0.5–15 μm, which reveals the great localization of particle deformation in the GDS process.
Properties of Cold Spray Nickel Based Coatings
Authors: Richer P. , Jodoin B. , Sansoucy E. , Ajdelsztajn L. , Kim G.E. 
Published: September 2022

Abstract
Nickel based alloys used in coating applications have been the focus of many studies, particularly in the aerospace industry. Their inherent corrosion and oxidation resistant properties have made them especially attractive for use as the metallic bond coat found in thermal barrier coating systems. Cold Spray is an emerging coating technology in which fine powder particles are accelerated in a supersonic flow and then deposited onto a substrate by means of plastic deformation. In this study, conventional CoNiCrAlY coatings and nanocrystalline nickel coatings are produced using the Cold Spray deposition technique. The coating quality is evaluated using scanning electron microscopy as well as porosity and microhardness measurements.
Effect of Particle Temperature on the Critical Velocity for Particle Deposition by Kinetic Spraying
Authors: Lee J.H. , Kim J.S. , Shin S.M. , Lee C.H. , Kim H.J. 
Published: September 2022

Abstract
This study evaluated the effects of particle temperature on deposition efficiency and critical velocity in kinetic spraying. A wide range of pressures and preheat temperatures of the process gas were used in these experiments to vary both particle velocity and temperature, and a bronze (Cu-Sn alloy) powder was deposited onto aluminum and bronze substrates. The deposition efficiency of the coatings was measured, and the critical velocity was estimated. The experimental results showed that the critical velocities of the bronze feedstock deposited onto either an aluminum or bronze substrate were different and that the critical velocity was strongly dependent on the particle temperature, which when increased, caused the critical velocity to decrease. Increasing the gas pressure caused an increase in particle velocity, while increases in the gas temperature not only affected the particle velocity but also the particle temperature. In our experiments, the critical velocity decreased by 50 m/s when the process gas temperature increased by 100 °C.
Critical and Maximum Velocities in Kinetic Spraying
Authors: Wu J.W. , Fang H.Y. , Lee C.H. , Yoon S.H. , Kim H.J. 
Published: September 2022

Abstract
Critical velocity has been accepted as a characteristic property of kinetic spraying (or cold gas dynamic spraying), which works by accelerating small solid particles to supersonic velocities and then impacting them onto a substrate. However, there is a lack of information about the impact of individual particles and their deposition behavior over a large range of impact velocities. To probe into the impact behavior of the particles and to elucidate the deposition mechanism, individual particle impaction tests have been carried out. A rebound phenomenon was found to occur at a high impact velocities, in which a large fraction of the particles rebounded. Based on experimental results, a model of a plastic particle impacting onto an un-deformed substrate was developed. The adhesion and rebound energies were calculated to estimate the particle/substrate interactions. A maximum impact velocity was found for particle deposition onto the substrate. The particle deposition behavior was controlled by the adhesion and rebound energies.
Characterization of Microstructure of TiO2 Coating Deposited by Vacuum Cold Spraying
Authors: Fan S.-Q. , Yang G.-J. , Liu G.-J. , Li C.-X. , Li C.-J. , Zhang L.-Z. 
Published: September 2022

Abstract
The control of microstructure of TiO2 coating through preparation methods influences significantly the performance of the coating. In this study, vacuum cold spray process as a new coating technology is employed to deposit nanocrystalline TiO2 coatings on glass and stainless steel substrates. TiO2 deposits were formed using two types of nanocrystalline TiO2 powders having mean particle diameters of 200 nm and 25 nm. The microstructure of the coating was characterized by scanning electron microscopy, x-ray diffraction analysis. The results demonstrate that a thick nanocrystalline TiO2 coating can be deposited by vacuum cold spray process. The coating was stacked of particles in agglomerate of several hundred nanometers. The coating presents a mesoporous microstructure which would be effective for applications in photocatalytic degradation, dye-sensitized solar cell and so on.
Measurement and Numerical Simulation of Particle Velocity in Cold Spraying
Authors: Li W.-Y. , Li C.-J. , Wang H.-T. , Li C.-X. 
Published: September 2022

Abstract
The velocity of cold spray particles was measured by a diagnostic system for thermal spray particles based on thermal radiation. A laser beam was employed to illuminate the cold sprayed particles in cold spraying for obtaining a sufficient radiant energy intensity for detection. The measurement was carried out for Cu particles of different mean particle sizes. The particle velocity was also estimated using the previously developed two-dimensional axisymmetric model. It was found that the measured results agreed well with the calculated ones. The proposed measurement method in this paper is reliable. On the other hand, it is confirmed that the particle acceleration behavior in cold spraying can be accurately predicted through the simulation method developed previously. The optimization of cold spray process can be conducted following the simulation method.
Comparison of the Microstructure of Cold Sprayed and Thermally Sprayed IN718 Coatings
Authors: Marrocco T. , McCartney D.G. , Shipway P.H. , Sturgeon A.J. 
Published: September 2022

Abstract
High-temperature nickel-based superalloys such as 1N718 are widely used in gas turbine components as they remain stable at operating temperatures up to ~750°C. There is now a growing interest in the repair and refurbishment of such components using spray deposition techniques. Although many investigations have been carried out to study the effect of conventional processing on the microstructure and mechanical properties of 1N718, much less attention has been given to the alloy when sprayed to form a coating. The purpose of the present study was to investigate and compare 1N718 deposits produced by HVOF spraying and cold gas spray deposition. Optical microscopy, scanning electron microscopy and X-ray diffraction were employed to examine the microstructural evolution of the coatings and to compare the deposition behaviour of the two different processes. Particular attention was paid to porosity, oxide content and the formation of secondary intermetallic phases. Coating microhardness and bond strength were also measured. Results will be presented and discussed in the context of the different thermal histories of the powder particles in the two processes.
Cold Spray Deposition of Metastable Alloys
Authors: Jodoin B. , Ajdelsztajn L. , Berube G. , Villafuerte J. 
Published: September 2022

Abstract
The proposed work describes recent efforts to develop metastable Al-Fe-V-Si coatings for internal-combustion engine applications with higher mechanical properties at high operating temperatures. To do so, the metastable solid powder alloy was engineered from rapid solidification technique (namely gas atomization). The metastable alloy powder was deposited using the Cold Spray process in order to produce protective coatings on top of existing parts. The critical velocity, above which Cold Spray deposition takes place, was successfully achieved and Al-Fe-V-Si coatings were produced. The microstructure of the feedstock powder was retained in the coatings produced, showing the potential of the Cold Spray process to produce metastable coatings for internal combustion engine applications.
Computational Modeling of Cold Spray Process: Effect of Substrate and Particle Size on Gas-particle Flow
Authors: Zhu Q. , Dolatabadi A. 
Published: September 2022

Abstract
This work involves modeling of cold spray process in order to predict gas flow as well as particle conditions upon impacting on a substrate. Particle normal velocity is found to be the most important factor to improve the deposition efficiency and coating quality. Particle velocity is influenced by the substrate geometry and location. The shape and strength of the bow shock near the substrate of different geometries (such as concave, convex, and flat) are studied, and particle normal velocities impacting on the substrates located at various stand-off distances are calculated. Furthermore, the numerical simulation is repeated with particles of various sizes and different feeding gas (Helium and Nitrogen). The results are compared to obtain the optimum substrate location and the appropriate particle size for each feeding gas.
Physical Bonding of Spray Particles to the Substrate for High Impact Velocity Droplet
Authors: Yang H. 
Published: September 2022

Abstract
The physical bonding of spray particles to the substrate is a main factor which contributes to the high adhesive strength of HVOF WC-Co coatings in addition to the mechanical interlocking effect. The adhesive strength between substrate and coatings deposited with partially melted particles under HVOF spray conditions has a significant contribution from physical bonding compared with conventional thermal spray processes having molten particles with relatively low velocity. The physical bonding results from the high impact velocity of partially-molten droplets during the HVOF spraying process.
Modelling a Plasma Torch for Atmospheric Plasma Spraying (APS): Optimization of Particle Injection Near the Torch Outlet According to the Gas Flow within the Torch
Authors: Marqués J.-L. , Ramachandran K. , Vaßen R. , Stöver D. 
Published: September 2022

Abstract
Understanding the particle injection into the gas flow issuing from an APS torch is necessary to optimize the spraying parameters. In order to solve numerically this task, the distribution of gas velocity and temperature at the torch outlet is required. In this work this is achieved by developing a model which not only delivers the solution for the electrically charged gas flow within the torch, but also includes the thermodynamical condition of minimum entropy production. This additional condition fixes the size of the electric arc inside the torch, whose radius is particularly responsible for the form of the calculated velocity and temperature profiles at the torch nozzle. The velocity and viscosity of the gas flow near the torch outlet mainly control the trajectory of particles injected into the gas flow. For the typical gas mass flow and torch power used in APS, the resulting temperatures at the gas core are slightly above the ionization temperature of the gas species. The radial location of the viscosity maximum corresponding to the ionization temperature is calculated, since this maximum strongly influences the particle trajectory. Finally, the influence of plasma fluctuations on the heat transfer to the injected particles is discussed.
Investigation of Splat Curling up in Thermal Spray Coatings
Authors: Xue M. , Mostaghimi J. , Chandra S. 
Published: September 2022

Abstract
The curling up of splats of molten metal deposited on a cold substrate was investigated both experimentally and numerically. An analytical model based on mismatch of thermal expansion between the splat and substrate was developed to calculate the deformation of the splat after curling up. The curling up angle at the edges of splats was predicted using the analytical model and compared with the experimental measurements. The prediction shows good agreement with the experiments.
Monte Carlo Simulation of Thermal Sprayed Coatings
Authors: Steinke T. , Bäker M. 
Published: September 2022

Abstract
The investigation of the splashing and spreading behaviour of an impacting powder particle during the plasma spraying process is a field of research often performed with the help of simulations. To simulate thermal sprayed coatings at large scale, the Monte Carlo method is a useful technology. In the Monte Carlo model presented in this manuscript, spreading starts from the particle impact point and continues over the coating so that the behaviour at steps or other surface structures can be taken into account. The discretisation of the model is only lateral so that the thickness of the coating perpendicular to the substrate can take arbitrary values. The rules for particle spreading and deposition used in the Monte Carlo model are derived from a fluid dynamics model. For a two-dimensional simulation the Monte Carlo results provides good agreement with the fluid dynamics results.
Application of Multiscale Modeling in the Coating Formation Simulation of APS-PYSZ-TBCs
Authors: Lugscheider E. , Bobzin K. , Nickel R. 
Published: September 2022

Abstract
The process parameters of atmospheric plasma spraying (APS) influence the coating formation and properties of partially yttria stabilized zirconia (PYSZ) thermal barrier coatings (TBCs). Simulations can be used to investigate this dependency and to design the coating process for a targeted production of TBCs. A whole process simulation was realized by modeling the linked sub-processes: plasma torch, plasma free jet, powder particles characteristics and coating formation. The coating formation can be described by model approaches with different physical assumptions and geometric scales. One approach is the simulation of single powder particles hitting the substrate surface. An alternative macroscale FEM-model-approach is applied in the coating formation simulation. A group of particles is pooled in a splash dependent on the pre-calculated particle distribution in front of the substrate. A third modeling approach is applied to calculate effective mechanical and thermodynamical properties of coatings dependent on the experimentally obtained or calculated microstructure of the PYSZ-TBC, which is based on different homogenization methods. The application of three simulation approaches in the whole process simulation of APS is discussed, advantages and disadvantages are elucidated. Results based on simulation and experiments are presented for a variation of process parameters. Missing links in the multiscale approach are detected to make suggestions for future modeling and simulation work.
Modeling Thermal Conductivity of Thermal Spray Coatings: Comparing Predictions to Experiments
Authors: Tan Y. , Longtin J.P. , Sampath S. 
Published: September 2022

Abstract
Thermal conductivity plays a critical role in the thermal transport of thermal sprayed coatings. In this paper, a combined image analysis and finite element method approach is developed to assess thermal conductivity from high-resolution scanning electron microscopy (SEM) images of the coating microstructure. Images are analyzed with a collection of image processing algorithms to reveal the microscopic coating morphology. The processed digital image is used to generate a two-dimensional finite element meshing in which pores, cracks and the bulk coating material are identified. The effective thermal conductivity is then simulated using a commercial finite element code. Results are presented for three coating material systems: yttria stabilized zirconia (YSZ), molybdenum and NiAl, and results are found to be in good agreement with experimental values, obtained using the laser flash method. YSZ coatings are also annealed and the analysis procedure repeated to determine if the technique could accurately assess changes in coating morphology.