Gas Dynamic Principles of Cold Spray

Dykhuizen, R.C.; Smith, Mark F.

doi:10.1361/105996398770350945

Cited by 536 publications

(221 citation statements)

References 5 publications

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“…The critical velocity at which Al particles start to stick to a smooth substrate was found to be around 650-670 m/s for pure aluminum [11,12]. Also, theoretical model predicted a critical velocity of between 620-670 m/s to observe an adiabatic shear instability for 25-µm Al particles on an Al substrate [13].…”

Section: In-flight Velocity Measurementsmentioning

confidence: 95%

Investigation of Al-Al2O3 Cold Spray Coating Formation and Properties

et al. 2007

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Section: In-flight Velocity Measurementsmentioning

confidence: 95%

Investigation of Al-Al2O3 Cold Spray Coating Formation and Properties

et al. 2007

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“…These were shortly followed by others, e.g. Dykhuizen and Smith [10] Gilmore et al [11] van Steenkiste et al [12] Kreye and Stoltenhoff [13] and Xiong et al [14]. The interest in CS has been increasing at a relatively fast rate in the past two decades, as reflected by the number of publications per year, Fig.…”

Section: Introductionmentioning

confidence: 92%

Cold spraying – A materials perspective

et al. 2016

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Cold spraying is a solid-state powder deposition process with several unique characteristics, allowing production of coatings or bulk components from a wide range of materials. The process has attracted much attention from academia and industry over the past two decades.The technical interest in cold spraying is twofold: first as a coating process for applications in surface technology, and second as a solid-state additive manufacturing process, offering an alternative to selective laser melting or electron beam melting methods. Moreover, cold spraying can be used to study materials behaviour under extremely high strain rates, high pressures and high cooling rates. The cold spraying process is thus considered to be relevant for various industrial applications, as well as for fundamental studies in materials science.This article aims to provide an overview of the cold spray process, the current understanding of the deposition mechanisms, and the related models and experiments, from a materials science perspective. IntroductionCold spraying (CS) is a solid-state material deposition technique, where micron-sized particles of a powder bond to a substrate as a result of high-velocity impact and the associated severe plastic deformation. Acceleration of particles to high velocities is obtained via expansion of a pressurised and (ironically) 'hot' gas through a diverging-converging nozzle.Despite heating the process gas -which is to provide higher acceleration of the gas and also to facilitate particle deformation through thermal softening -the feedstock remains in the solid state throughout the entire process; hence the name 'cold' spraying. This is to underline the contrast to conventional thermal spraying where particles are completely or partially molten upon impact onto the substrate. Alternative terminology includes cold gas spray, micro cold spray, cold gas dynamic spray, kinetic spray, supersonic particle deposition and metal powder application (MPA), all of which refer to the same principle of solid-state powder deposition as described above. CS is used for coating and repair. It is also used for additive manufacturing (AM) at relatively high deposition rates as compared to the methods based on selective laser or electron beam melting. The main advantage of CS is that it alleviates the problems associated with high temperature processing of materials, such as oxidation and unfavourable structural changes. It is possibly the only continuous method to produce bulk components of metastable materials that are available only in the powder form, e.g. as obtained from mechanical attrition or gas atomisation. The aim of the present paper is to provide an overview of CS from a materials perspective, particularly for a broader audience in materials research, e.g. with interest in dynamic phenomena, plasticity and phase transformations. In terms of application and properties, CS is perhaps best to be compared to thermal spraying processes, as in [24,25]. In view of relevant physical phenomena, however, CS is mos...

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“…The following well-known gas dynamic equations are used for isentropic flow of an ideal gas with constant thermodynamic properties through a convergent-divergent nozzle (Ref [10][11][12][13][14]30):…”

Section: Appendix A: Gas Dynamic Equations For Flow In a Nozzlementioning

confidence: 99%

“…A most determining factor for bonding is the velocity of the impacting particle. Bonding occurs if the particle velocity upon impact, v pi , becomes greater than a critical value, v cr (Ref [10][11][12][13][14][15][16][17][18]. The conditions that lead to particle bonding can be identified with respect to what is referred to as window of deposition.…”

Section: Introductionmentioning

confidence: 99%

On Parameter Selection in Cold Spraying

et al. 2011

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For cold spraying, a method for the construction of the window of deposition and the selection of optimum process parameters is presented. Initially, particle impact velocity and the critical particle velocity for bonding are worked out and expressed explicitly in terms of key process and material parameters. Subsequently, the influence of particle velocity on coating characteristics is examined in view of the results of experiments and simulations. It has been found that main coating characteristics can be described as a unique function of the ratio of particle velocity to critical velocity, here referred to as g. Finally, coating properties are linked directly to primary process parameters via parameter selection maps, where contours of constant g are plotted on a plane of gas temperature versus gas pressure. Inferences of the presented method and the resulting parameter selection maps are discussed for the example of copper as feedstock material.

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Gas Dynamic Principles of Cold Spray

Cited by 536 publications

References 5 publications

Investigation of Al-Al2O3 Cold Spray Coating Formation and Properties

Investigation of Al-Al2O3 Cold Spray Coating Formation and Properties

Cold spraying – A materials perspective

On Parameter Selection in Cold Spraying

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