Microstructure Refinement of Cold-Sprayed Copper Investigated By Electron Channeling Contrast Imaging

AbstractThe electron channeling contrast imaging technique was used to investigate the microstructure of copper coatings fabricated by cold gas dynamic spray. The high velocity impact characteristics for cold spray led to the formation of many substructures, such as high density dislocation walls, dislocation cells, deformation twins, and ultrafine equiaxed subgrains/grains. A schematic model is proposed to explain structure refinement of Cu during cold spray, where an emphasis is placed on the role of dislocation configurations and twinning.

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Material Properties of Thick Aluminum Coating Made by Cold Gas Dynamic Spray Deposition

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.345-346.1097 ◽

2007 ◽

Vol 345-346 ◽

pp. 1097-1100

Author(s):

Jae Chul Lee ◽

Doo Man Chun ◽

Sung Hoon Ahn ◽

Caroline S. Lee

Keyword(s):

Electrical Resistivity ◽

Elastic Modulus ◽

Cold Spray ◽

Material Properties ◽

Gas Dynamic ◽

Macro Scale ◽

Cold Gas Dynamic Spray ◽

Gas Dynamic Spray ◽

Scale Deposition ◽

Cold Gas

Cold gas dynamic spray is a relatively new coating process by which coatings can be produced without significant heating during the process. Cold gas dynamic spray is conducted by powder sprayed using supersonic gas jet, and generally called the kinetic spray or cold spray. Its low process temperature can minimize the thermal stress and also reduce the deformation of the substrate. In this study, thick or macro scale deposition was studied while most researches on cold-spray have focused on micro scale coating. Measured material properties of macro scale deposition layer showed that elastic modulus and hardness were lower and electrical resistivity was higher than those of reference substrate material. The main causes of changed material properties were investigated by FE-SEM (Field Emission Scanning Electron Microscope) and EDS (Energy Dispersive X-ray Spectrometer) data. In this result, porous micro structure generated by imperfect plastic deformation might cause decrease in elastic modulus and hardness of the deposition layer by cold spray, and oxidized Al particles increased the electrical resistivity.

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Microstructure and Mechanical Properties of Ti Cold-Spray Splats Determined by Electron Channeling Contrast Imaging and Nanoindentation Mapping

Microscopy and Microanalysis ◽

10.1017/s1431927615000240 ◽

2015 ◽

Vol 21 (3) ◽

pp. 570-581 ◽

Cited By ~ 21

Author(s):

Dina Goldbaum ◽

Richard R. Chromik ◽

Nicolas Brodusch ◽

Raynald Gauvin

Keyword(s):

Mechanical Properties ◽

Cold Spray ◽

Electron Backscatter Diffraction ◽

Substrate Material ◽

Contrast Imaging ◽

Electron Channeling ◽

Metallurgical Bonding ◽

Resolution Electron ◽

Backscatter Diffraction ◽

The Impact

AbstractCold spray is a thermo-mechanical process where the velocity of the sprayed particles affects the deformation, bonding, and mechanical properties of the deposited material, in the form of splats or coatings. At high strain rates, the impact stresses are converted into heat, a phenomenon known as adiabatic shear, which leads to grain re-crystallization. Grain re-crystallization and growth are shown to have a direct impact on the mechanical properties of the cold-sprayed material. The present study ties the microstructural features within the cold-sprayed Ti splats and the substrate to the bonding mechanism and mechanical properties. High-resolution electron channeling contrast imaging, electron backscatter diffraction mapping, and nanoindentation were used to correlate the microstructure to the mechanical properties distribution within the titanium cold-spray splats. The formation of nanograins was observed at the titanium splat/substrate interface and contributed to metallurgical bonding. An increase in grain re-crystallization within the splat and substrate materials was observed with pre-heating of the substrate. In the substrate material, the predominant mechanism of deformation was twinning. A good relationship was found between the hardness and distribution of the twins within the substrate and the size distribution of the re-crystallized grains within the splats.

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Characterization of Cold Spray Titanium Deposits by X-Ray Microscopy and Microtomography

Microscopy and Microanalysis ◽

10.1017/s1431927608080355 ◽

2008 ◽

Vol 14 (3) ◽

pp. 260-266 ◽

Cited By ~ 16

Author(s):

Saden H. Zahiri ◽

Sheridan C. Mayo, ◽

Mahnaz Jahedi

Keyword(s):

Cold Spray ◽

Commercial Purity ◽

X Ray ◽

Cold Gas Dynamic Spray ◽

Gas Dynamic Spray ◽

Titanium Structure ◽

Porosity Measurements ◽

Deposition Technology ◽

Unique Capability

AbstractCold gas dynamic spray (cold spray) is a rapid deposition technology in which particles deposit at velocities above the speed of sound (∼340 ms−1). Generally, porosity forms in cold spray deposits due to insufficient deformation of particles. In this study, the unique capability of the X-ray microscopy and microtomography is utilized to visualize the internal structure of deposited material. The results show that this characterization technique successfully reveals porosities in the cold spray commercial purity (CP) titanium structure. Furthermore, microtomography images confirmed the experimental results for porosity measurements in which helium (compared with nitrogen) as carrier gas significantly decreases porosity in cold spray CP titanium.

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Porosity Characterization of Cold Sprayed Stainless Steel Coating Using Three-Dimensional X-ray Microtomography

Coatings ◽

10.3390/coatings8090326 ◽

2018 ◽

Vol 8 (9) ◽

pp. 326 ◽

Cited By ~ 3

Author(s):

Yingying Wang ◽

Jérôme Adrien ◽

Bernard Normand

Keyword(s):

Stainless Steel ◽

Cold Spray ◽

Three Dimensional ◽

X Ray ◽

Steel Coating ◽

Coating Morphology ◽

Cold Gas Dynamic Spray ◽

Gas Dynamic Spray ◽

Non Destructive

Cold gas-dynamic spray (cold spray) is an evolving coating deposition and restoration technology in which particles are deposited above the sonic speed. This paper presents the non-destructive three-dimensional characterization of cold sprayed stainless steel coating. The visualization of coating morphology and volumetric porosity and the analyses of porosity size and spatial distributions confirmed that dense stainless steel coating with non-connected, micron-sized gradient porosity can be successfully produced by cold spray. The suitability of X-ray tomography for characterizing cold sprayed coatings was also assessed.

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Porosity Characterization of Cold Sprayed Stainless Steel Coating Using Three-Dimensional X-ray Microtomography

10.20944/preprints201807.0448.v1 ◽

2018 ◽

Author(s):

Yingying Wang ◽

Jérôme Adrien ◽

Bernard Normand

Keyword(s):

Stainless Steel ◽

Cold Spray ◽

Three Dimensional ◽

X Ray ◽

Steel Coating ◽

Coating Morphology ◽

Cold Gas Dynamic Spray ◽

Gas Dynamic Spray ◽

Non Destructive

Cold gas-dynamic spray (cold spray) is an evolving coating deposition and restoration technology in which particles are deposited above the sonic speed. This paper presents the non-destructive three-dimensional characterization of cold sprayed stainless steel coating. The visualization of coating morphology and volumetric porosity, and the analyses of porosity size and spatial distributions confirmed that dense stainless steel coating with non-connected, micron-sized gradient porosity is successfully produced by cold spray. The suitability of X-ray tomography for characterizing cold sprayed coatings is assessed.

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Nanomechanical Characterization for Cold Spray: From Feedstock to Consolidated Material Properties

Metals ◽

10.3390/met10091195 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1195 ◽

Cited By ~ 2

Author(s):

Bryer C. Sousa ◽

Matthew A. Gleason ◽

Baillie Haddad ◽

Victor K. Champagne ◽

Aaron T. Nardi ◽

...

Keyword(s):

Cold Spray ◽

Advanced Manufacturing ◽

High Deposition Rate ◽

Manufacturing Method ◽

Nanoindentation Testing ◽

Measurement Mode ◽

Cold Gas Dynamic Spray ◽

Gas Dynamic Spray ◽

Continuous Stiffness Measurement ◽

Metal Additive

Cold gas-dynamic spray is a solid-state materials consolidation technology that has experienced successful adoption within the coatings, remanufacturing and repair sectors of the advanced manufacturing community. As of late, cold spray has also emerged as a high deposition rate metal additive manufacturing method for structural and nonstructural applications. As cold spray enjoys wider recognition and adoption, the demand for versatile, high-throughput and significant methods of particulate feedstock as well consolidated materials characterization has also become more notable. In order to address the interest for such an instrument, nanoindentation is presented herein as a viable means of achieving the desired mechanical characterization abilities. In this work, conventionally static nanoindentation testing using both Berkovich and spherical indenter tips, as well as nanoindentation using the continuous stiffness measurement mode of testing, will be applied to a range of powder-based feedstocks and cold sprayed materials.

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Quantitative structure determination of interfaces through Z-contrast imaging and electron energy loss spectroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100162983 ◽

1996 ◽

Vol 54 ◽

pp. 104-105

Author(s):

S. J. Pennycook ◽

P. D. Nellist ◽

N. D. Browning ◽

P. A. Langjahr ◽

M. Rühle

Keyword(s):

Grain Boundaries ◽

Cuprate Superconductors ◽

Structure Refinement ◽

3D Structure ◽

Real Space ◽

Contrast Imaging ◽

Coordination Polyhedra ◽

Burgers Vector ◽

Z Contrast ◽

Contrast Image

The simultaneous use of Z-contrast imaging with parallel detection EELS in the STEM provides a powerful means for determining the atomic structure of grain boundaries. The incoherent Z-contrast image of the high atomic number columns can be directly inverted to their real space arrangement, without the use of preconceived structure models. Positions and intensities may be accurately quantified through a maximum entropy analysis. Light elements that are not visible in the Z-contrast image can be studied through EELS; their coordination polyhedra determined from the spectral fine structure. It even appears feasible to contemplate 3D structure refinement through multiple scattering calculations.The power of this approach is illustrated by the recent study of a series of SrTiC>3 bicrystals, which has provided significant insight into some of the basic issues of grain boundaries in ceramics. Figure 1 shows the structural units deduced from a set of 24°, 36° and 65° symmetric boundaries, and 24° and 45° asymmetric boundaries. It can be seen that apart from unit cells and fragments from the perfect crystal, only three units are needed to construct any arbitrary tilt boundary. For symmetric boundaries, only two units are required, each having the same Burgers, vector of a<100>. Both units are pentagons, on either the Sr or Ti sublattice, and both contain two columns of the other sublattice, imaging in positions too close for the atoms in each column to be coplanar. Each column was therefore assumed to be half full, with the pair forming a single zig-zag column. For asymmetric boundaries, crystal geometry requires two types of dislocations; the additional unit was found to have a Burgers’ vector of a<110>. Such a unit is a larger source of strain, and is especially important to the transport characteristics of cuprate superconductors. These zig-zag columns avoid the problem of like-ion repulsion; they have also been seen in TiO2 and YBa2Cu3O7-x and may be a general feature of ionic materials.

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