Dissipative properties of Al-(Fe, Cr) vacuum coatings with different composite structures

Dissipative properties of Al-(Fe, Cr) vacuum coatings with different composite structures

Heterogeneous Al-(Fe, Cr) vacuum coatings were produced by electron beam vapor physical deposition (EB-PVD). It is shown that the composite structure (CS) of 85 at.% Al-(Fe, Cr) coatings consists of an aluminum-based matrix, strengthened by particles of λ-phase (CS-I), whereas that of 71 at.% Al-(Fe...

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Bibliographic Details
Published in:Surface & coatings technology Vol. 367; pp. 179 - 186
Main Authors: Skorodzievskii, V.S., Ustinov, A.I., Polishchuk, S.S., Demchenkov, S.A., Telychko, V.O.
Format: Journal Article
Language:English
Published: Lausanne Elsevier B.V 15-06-2019
Elsevier BV
Subjects:
Aluminum
Aluminum alloys
Amplitudes
Chromium
Composite structure
Composite structures
Cracks
Damping capacity
Diffusion coatings
Dislocations
Electron beams
Electron microscopy
Energy dissipation
Grain boundary diffusion
High temperature
Iron
Microhardness
Physical vapor deposition
Properties (attributes)
Aluminum alloys
Damping capacity
Electron microscopy
Composite structure
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Summary:Heterogeneous Al-(Fe, Cr) vacuum coatings were produced by electron beam vapor physical deposition (EB-PVD). It is shown that the composite structure (CS) of 85 at.% Al-(Fe, Cr) coatings consists of an aluminum-based matrix, strengthened by particles of λ-phase (CS-I), whereas that of 71 at.% Al-(Fe, Cr) coatings consists of fragmented grains of metastable bcc-phase and nano-sized particles of tetragonal Al(Cr, Fe)2 phase located along the boundaries of bcc-phase subgrains (CS-II). Effect of the different composite structures on their dissipative properties was studied. The coatings with the two types of CS have approximately the same microhardness, Hμ = 6–7 GPa, while their dissipative properties in the temperature range of 293–623 K are substantially different. It is found that the damping capacity (DC) for coatings with CS-II are 2–3 times higher than that of the coatings with CS-I(at strain amplitude of ε ~ 4 × 10−4). Moreover, CS-II coatings are characterized by the amplitude-dependent damping curves with a maximum, while CS-I coatings exhibit a monotonic increase with amplitude. These differences in the coatings DC may be related to the distinction of mechanisms of energy dissipation in them. In the case of CS-I coatings, the main dissipation mechanisms are dislocation processes and grain-boundary diffusion at elevated temperatures, whereas in the case of CS-II coatings it can be due to the friction of nano-cracks edges. •85 at% Al-(Fe, Cr) and 71 at.% Al-(Fe, Cr) coatings were obtained using EB PVD.•The values of hardness for both the coatings were near the same: Hμ ~ 6–7 GPa.•Damping capacity of 71 at.% Al-(Fe, Cr) coating is significantly higher.•This distinction in damping is due to different energy dissipation mechanisms.
ISSN:0257-8972
1879-3347
DOI:10.1016/j.surfcoat.2019.03.074