Structural Transformation and Mechanical Properties of Cold Sprayed Nickel Coatings after Annealing

Zou, Yu; Ahmad, Razi; Szpunar, Jerzy A.; Irissou, Éric; Yue, Stephen

doi:10.1557/proc-1151-ss01-06

Cited by 2 publications

(2 citation statements)

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“…Due to recrystallization, the microstructure of the as-sprayed nickel is more uniform and the hardness is reduced after annealing at 400 or 600 °C for 1 h (Figure 10). 30 Figure 10a−d show the morphologies of Vickers microhardness indents on the as-sprayed and annealed nickel samples. Local cracks are observed at the edge of the indent of the as-sprayed and 200 °C annealed samples, but those annealed at 400 and 600 °C exhibit relatively smooth indent edges without cracks.…”

Section: Postprocessing Heat Treatment On Microstructure Evolutionmentioning

confidence: 99%

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Cold Spray Additive Manufacturing: Microstructure Evolution and Bonding Features

Zou

2021

Acc. Mater. Res.

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Conspectus Most metal additive manufacturing (AM) methods involve the melting or sintering of feedstock powder or wire using an energy source (laser, electron beam, or electric arc). Solid-state AM, sometimes also known as non-beam-based AM, is a process in which the deposited material does not melt and is built up layer-by-layer, typically through severe plastic deformation. Initially considered to be a coating technique, by virtue of its high deposition rate, cold spray additive manufacturing (CSAM) is attractive as a solid-state AM technology. In the CSAM process, metal powder particles are impacted onto a substrate at a supersonic velocity and relatively low temperature. The CSAM process reduces or eliminates many problems associated with melting or beam-based AM methods, making the CSAM technically attractive for a wide range of applications, such as in the aerospace, automobile, marine, biomedical, machinery, and energy sectors. In this Account, the author briefly reviews the setup of a cold spray system and discusses the strengths and drawbacks of CSAM compared with thermal sprays and beam-based AM processes, as well as applications in relevant industries. The author summarizes the bonding mechanisms proposed for the cold spray process. The focus of this Account is to review the microstructure evolution of several typical model metals (copper, nickel, aluminum, and titanium) during the cold spray process. The author shows a large variety of microstructure characteristics (recrystallized grains, annealing twins, shear bands, submicron-sized grains, deformation twins, and nanometer-sized grains) in cold-sprayed copper, dynamic recrystallization of cold-sprayed nickel, and the formation of refined grains even below 10 nm in size in cold-sprayed aluminum. The magnitude of the stacking fault energy of as-sprayed materials considerably influences the microstructure after cold spray and postprocessing. Due to the relatively low thermal conductivity and ductility of titanium, cold spraying of titanium shows both a high deposition efficiency and relatively high porosity of as-sprayed parts, as well as a heterogeneous microstructure. Moreover, the Account introduces the postprocessing heat treatment and nanoindentation characterization of cold-sprayed materials. A fundamental understanding of microstructure evolution during and after the cold spray process is essential for optimal mechanical properties. Lastly, the author provides a perspective on applying old lessons and taking advantage of new techniques and materials, including powder characterization, hybrid additive manufacturing, machine learning for searching process windows, nanomechanical testing, and emerging alloys (high-entropy alloys, nanocrystalline alloys, and quasicrystals), to advance the research and applications of CSAM.

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Section: Postprocessing Heat Treatment On Microstructure Evolutionmentioning

confidence: 99%

“…(e)–(h) The corresponding EBSD IQ maps reveal the microstructure revolution and residual stress released when the annealing temperature is increased. Reproduced with permission from ref . Copyright 2008 Springer Nature.…”

Section: Microstructure Evolutionmentioning

confidence: 99%

Cold Spray Additive Manufacturing: Microstructure Evolution and Bonding Features

Zou

2021

Acc. Mater. Res.

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Cold Spray—Advanced Characterization

Srinivasan¹

2016

High Pressure Cold Spray

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This chapter elucidates the indispensable role of characterization in the development of cold-sprayed coatings and illustrates some of the common processes used during coatings development. Emphasis is placed on the advanced microstructural characterization techniques that are used in high-pressure cold spray coating characterization, including residual-stress characterization. The chapter includes some preliminary screening of tool hardness and bond adhesion strength, as well as a distinction between surface and bulk characterization techniques and their importance for cold spray coatings. The techniques covered are optical microscopy, X-Ray diffraction, scanning electron microscopy, focused ion beam machining, electron probe microanalysis, transmission electron microscopy, and electron backscattered diffraction. The techniques also include electron channeling contrast imaging, X-Ray photoelectron spectroscopy, X-ray fluorescence, Auger electron spectroscopy, Raman spectroscopy, oxygen analysis, and nanoindentation.

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Structural Transformation and Mechanical Properties of Cold Sprayed Nickel Coatings after Annealing

Cited by 2 publications

References 7 publications

Cold Spray Additive Manufacturing: Microstructure Evolution and Bonding Features

Cold Spray Additive Manufacturing: Microstructure Evolution and Bonding Features

Cold Spray—Advanced Characterization

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