Dynamic amorphization and recrystallization of metals in kinetic spray process

Xiong, Yao; Kang, Ki-Weon; Bae, Gyuyeol; Yoon, Suk Bon; Lee, Changhee

doi:10.1063/1.2928218

Cited by 81 publications

(32 citation statements)

References 17 publications

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“…as observed in a cold-sprayed Al-Mg alloy [110]. There have also been reports of dynamic amorphization in Al-Al, Ni-Al [124], Al-Cu [125], Cu-Ni [126], Al-Mg [127] and Fe-Al [128,129] systems, over a layer of up to tens of nanometres thickness. For the case of metallic glasses, on the other hand, CS may result in nanocrystallisation of the initially amorphous phase [89].…”

Section: Microstructurementioning

confidence: 70%

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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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Section: Microstructurementioning

confidence: 70%

“…For the case of metallic glasses, on the other hand, CS may result in nanocrystallisation of the initially amorphous phase [89]. More examples of amorphization and dynamic recrystallization in cold-sprayed deposits are reported in the literature [124,[130][131][132].…”

Section: Microstructurementioning

confidence: 99%

Cold spraying – A materials perspective

et al. 2016

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“…Microscopically, the inhomogeneous microstructures are generated between inner and near-interfacial region of deposited particles ( Ref 49,[52][53][54] by an assistance of stored strain-energy-relieving phenomena: grain refinement, dynamic recovery (DRV), dynamic recrystallization (DRX), static recovery (SRV), and static recrystallization (SRX) (Ref 52,(55)(56)(57)(58)(59)(60)(61)(62). Additionally, local phase transformations such as amorphization, crystallization (amorphous alloy), and intermetallic compound creation can occur in the vicinity of the interface (Ref [63][64][65]. Above this, post-heat treatment of as-sprayed specimens has significant effect on the microstructure by causing phase transformation or annealing phenomenon .…”

Section: Introductionmentioning

confidence: 99%

Microstructure of Kinetic Spray Coatings: A Review

2015

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Kinetic spray process has been applied to various industrial fields such as automotive, aviation, and defense industries due to its availability to produce high-performing coating layer. However, since the properties of kinetic-sprayed coating layer are significantly affected by the microstructures of deposit, the microstructures of the deposit should be controlled to acquire advanced coating layer and, accordingly, deep understanding of microstructural evolution must be achieved before controlling the microstructure of the coating layer. This paper gives an overview of contents related to the microstructure of kineticsprayed deposition. The most powerful influencing factors in microstructural evolution of kinetic-sprayed coating layer are instant generation of thermal energy and high-strain, high-strain-rate plastic deformation at the moment of particle impact. A high-density coating layer with low porosity can be produced, although some micro-cracks are occasionally induced at the interparticle boundary or at the inner region of the particles. Also, a microstructure which is distinct from the inner particle region is created in the vicinity of the particle-particle or particle-substrate interface region. However, almost no crystal phase transformation or chemical reaction is induced since the deposited particles are not heated directly by a thermal energy source.

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“…[17][18][19][20] Many researchers hence have made TEM samples by the FIB method from micron-sized powders or small splats or thick coating layers at a desired location. 1,[21][22][23][24][25][26][27][28][29] Because the FIB is an imaging tool in its own right as well as the milling and thinning capability in sample preparation, 30) during the FIB fabrication, one can check the milling state and get images of the sample.…”

Section: Introductionmentioning

confidence: 99%

“…1,[21][22][23][24] For the high resolution images, several researchers prepared firstly the cross section of a single splat by a conventional polishing method using silicon carbide (SiC) papers or the FIB method and then, from the cross section, several TEM samples were made respectively at desired locations within the single splat. [27][28][29] Once a TEM sample was made and observed, it is generally impossible to prepare much thinner sample at the desired position. By the FIB milling, however, it is possible to conduct re-thinning at any interested region even after TEM samples were already observed by electron microscopes.…”

Section: Introductionmentioning

confidence: 99%

Observation of High Resolution Microstructures in Thermal Sprayed Coatings and Single Deposited Splats Using Ion Beam Milling

et al. 2011

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We have investigated microstructures of thermal sprayed coatings and single deposited splats using two types of ion beam milling: one is broad argon ion beam for the cross-sectioning of thermal sprayed coatings in a cross section polisher and the other is focused gallium ion beam for the cross-sectioning and transmission electron microscopy (TEM) sample preparation of single splats. The cross section of tungsten carbidecobalt (WC-Co) coatings fabricated by the polisher showed that it created a mirrored surface with minimized artifacts such as pull-outs of ceramic particles or smearings of pores which can be made by conventional metallographic preparations. A thin and locally re-thinned membrane of single nickel (Ni) splat was feasible to observe the internal interface of particle/substrate in high resolution atomic scale images. Substrate was heavily deformed by the impact of nickel particle with high kinetic and thermal energies. The particle and the substrate were intimately bonded without any voids or gaps.

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Dynamic amorphization and recrystallization of metals in kinetic spray process

Cited by 81 publications

References 17 publications

Cold spraying – A materials perspective

Cold spraying – A materials perspective

Microstructure of Kinetic Spray Coatings: A Review

Observation of High Resolution Microstructures in Thermal Sprayed Coatings and Single Deposited Splats Using Ion Beam Milling

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