Strain‐Induced Phase Transformation of MCrAlY

Borchers, C.; Stoltenhoff, T.; Hahn, Matthias; Schulze, Matthias; Assadi, H.; Suryanarayana, C.; Gärtner, F.; Klassen, Thomas

doi:10.1002/adem.201400174

Cited by 18 publications

(4 citation statements)

References 53 publications

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“…That is, the impact can result in deformation-induced transformation of an initially metastable phase into a more stable state, e.g. bcc to fcc in steel 316L [134] and in MCrAlY [135].…”

Section: Microstructurementioning

confidence: 99%

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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“…That is, the impact can result in deformation-induced transformation of an initially metastable phase into a more stable state, e.g. bcc to fcc in steel 316L [134] and in MCrAlY [135].…”

Section: Microstructurementioning

confidence: 99%

Cold spraying – A materials perspective

et al. 2016

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“…Comparing the XRD patterns of the as-received and milled powders indicate that β-phase precipitates disappear during milling process, probably due to dissolution into the matrix (γ phase). This phenomenon has been reported in the case of several MCrAlY-based alloys [4,32,[51][52][53]. The absence of the β phase peaks on the milled powder spectrum could be the result of experiencing severe plastic deformation during milling.…”

Section: Distribution Of Nano-ceomentioning

confidence: 52%

Study on production of modified MCrAlY powder with nano oxide dispersoids as HVOF thermal spray feedstock using mechanical milling

Zakeri

Ghadami

Rouhaghdam

et al. 2020

Mater. Res. Express

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This paper investigates NiCoCrAlY-CeO 2 nanocomposite powders prepared by mechanical milling process. At first, micron-sized ceria powder was pre-milled to obtain nano-sized powders and then 1 wt% CeO 2 was mixed with the conventional NiCoCrAlY powder and milled under three sets of parameters. The conventional and milled powders were deposited on low carbon steel substrates by HVOF thermal spray technique. X-ray diffraction (XRD), scanning electron microscopy (SEM), fieldemission scanning electron microscopy (FESEM) and image analyzing method were used to characterize the prepared powders and coatings. Microstructural characterization showed that the milled powders underwent morphological and phase transitions. Through the microstructural and compositional analyses, it was found that a homogeneous distribution of CeO 2 nano-dispersoids in the NiCoCrAlY matrix was obtained. The resulting coatings showed that by using optimized milling parameters, required particle size and suitable morphology for thermal spray can be achieved.

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“…Part of a common description for kinetic spray processes as CS and AD concerns the mechano-chemical phenomena driven by the particle deformation and the resulting change in the chemical state of the particle surface, as well as particle stabilization by contact within short time scales 33) observed in AD, may be related to mechanochemistry. In some rare cases, similar pressureinduced phase changes and possible similarities to ball milling could be also observed in CS, when low packing density crystallographic powder structures and impact conditions allow for the transformation to denser phases (Ref 64,65). A quantitative unified model to explain these phenomena is challenging but required.…”

Section: Common Models For Ad and Cs Of Brittle Materialsmentioning

confidence: 96%

Kinetic Spraying of Brittle Materials: From Layer Formation to Applications in Aerosol Deposition and Cold Gas Spraying

2021

J Therm Spray Tech

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This special issue of the Journal of Thermal Spray Technology focuses on kinetic spraying processes of mainly brittle materials. The definition of ''kinetic spraying'' involves the impact of materials in the solid state as expressed by technical terms as ''aerosol deposition'' (AD), ''vacuum kinetic spray,'' ''granule spray in vacuum,'' as well as ''cold gas spraying.'' Applying kinetic spraying to brittle materials covers the deposition of ceramics and 123

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Strain‐Induced Phase Transformation of MCrAlY

Cited by 18 publications

References 53 publications

Cold spraying – A materials perspective

Cold spraying – A materials perspective

Study on production of modified MCrAlY powder with nano oxide dispersoids as HVOF thermal spray feedstock using mechanical milling

Kinetic Spraying of Brittle Materials: From Layer Formation to Applications in Aerosol Deposition and Cold Gas Spraying

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