Mechanical properties of single and polycrystalline α-Al2O3 coatings grown by chemical vapor deposition

Konstantiniuk, Fabian; Tkadletz, Michael; Kainz, Christina; Czettl, Christoph; Schalk, Nina

doi:10.1016/j.surfcoat.2021.126959

Cited by 33 publications

(20 citation statements)

References 25 publications

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“…Additionally, the lower value of fracture toughness of α-Al2O3 compared to κ-Al2O3 is in agreement with literature, as a material strength enhancement is accompanied with a toughness decrease [30,31]. 6 (marked by arrows), can be found when grains are aligned for fracture on the basal plane [28,32]. Furthermore, (0001) oriented single crystalline α-Al 2 O 3 , where fracture occurs on the prism planes, is reported to exhibit smooth fracture surfaces [28,32].…”

Section: Mechanical Propertiessupporting

confidence: 92%

“…Coatings 2021, 11, x FOR PEER REVIEW 8 of 10 fracture cross-section. According to prior literature, step-like fracture surfaces of α-Al2O3 grains, as are visible in the lower part of the micro-cantilever in Figure 6 (marked by arrows), can be found when grains are aligned for fracture on the basal plane [28,32]. Furthermore, (0001) oriented single crystalline α-Al2O3, where fracture occurs on the prism planes, is reported to exhibit smooth fracture surfaces [28,32].…”

Section: Mechanical Propertiesmentioning

confidence: 53%

“…6 (marked by arrows), can be found when grains are aligned for fracture on the basal plane [28,32]. Furthermore, (0001) oriented single crystalline α-Al 2 O 3 , where fracture occurs on the prism planes, is reported to exhibit smooth fracture surfaces [28,32]. This corresponds with the observation from the IPF-Y EBSD maps of the micro-cantilevers in Figure 4a, which shows randomly oriented grains in the lower part of the micro-cantilevers and highly (0001) oriented grains at the top of the micro-cantilevers.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

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Fracture Properties of α– and ĸ–Al2O3 Hard Coatings Deposited by Chemical Vapor Deposition

Konstantiniuk

Tkadletz

Czettl³

et al. 2021

Coatings

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Although α– and κ–Al2O3 hard coatings deposited by chemical vapor deposition are well established in the metal-cutting industry for their ability to increase the performance and lifetime of cutting tools, the literature on their fracture properties is scarce. Thus, within this study, the microstructure and mechanical properties of α– and κ–Al2O3 coatings were investigated and compared to each other. X-ray diffraction and scanning electron microscopy combined with electron backscatter diffraction showed that both coatings exhibited a fiber texture, where the α-Al2O3 coating displayed a (0001) texture and the κ–Al2O3 coating a (001) texture with a certain (013) contribution. Higher hardness and Young’s modulus values of 31.0 ± 0.9 GPa and 474.6 ± 12.5 GPa, respectively, were obtained for the α–Al2O3 coating, compared to 24.2 ± 0.8 GPa and 356.8 ± 7.9 GPa for κ–Al2O3. While the α–Al2O3 coating exhibited a higher fracture stress of 8.1 ± 0.3 GPa (compared to 6.4 ± 0.6 GPa for κ–Al2O3), the κ–Al2O3 coating showed a higher fracture toughness of 4.4 ± 0.3 MPa*m1/2 (compared to 3.2 ± 0.3 MPa*m1/2 for alpha).

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Section: Mechanical Propertiessupporting

confidence: 92%

Section: Mechanical Propertiesmentioning

confidence: 53%

Section: Mechanical Propertiesmentioning

confidence: 99%

See 1 more Smart Citation

Fracture Properties of α– and ĸ–Al2O3 Hard Coatings Deposited by Chemical Vapor Deposition

Konstantiniuk

Tkadletz

Czettl³

et al. 2021

Coatings

Self Cite

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“…Additionally, many authors have studied the bilayer number influence on the coatings used as thermal barriers like the multilayer type, observing the cracks and fracture behaviors from a mechanical standpoint, suggesting the following effects [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Influence of Thermal Degradation on the Mechanical Properties of Coatings [8YSZ/Al2O3]n Subjected to Thermals Cycles

Ortiz¹,

Hernandez-Rengifo²,

Caicedo³

2022

Tribol. Ind.

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This study is based on the thermal degradation presented in the multilayer coatings [8YSZ/α-Al2O3]n when subjected to thermal cycles, focusing mainly on the analysis of the mechanical properties before and after these. To determine thermal degradation, the coatings were analyzed by XRD before and after thermal cycling. From these results, the presence of a tetragonal phase and an alpha phase belonging to (8YSZ and Al2O3) respectively was determined before the thermal cycles. After the cycles, show new peaks attributed to 2 important factors, the appearance of a monoclinic and cubic phase belonging to 8YSZ and peaks due to the presence of substrate oxides produced by a delamination of the coating and that decreased in intensity as increase in the bilayers number. Mainly, it was determined for the 70 bilayers coating, which presented the best mechanical properties before the thermal cycles, a decrease of 34.44% and 6.41% for hardness and elasticity modulus respectively, after the thermal cycles. From this research, it was concluded that the coating [8YSZ/α-Al2O3]n with 70 bilayers, presented the highest resistance to thermal wear generated in the coatings.

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“…Konstantiniuk et al used chemical vapor deposition to deposit single crystal and polycrystalline α-Al 2 O 3 coatings on sapphire substrates with different crystal orientations, and prepared unnotched and notched microcantilevers. The (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) single crystalline coating which was aligned for fracture on the C-plane, exhibited the highest fracture stress and fracture toughness [25]. Graça et al used the SEVNB method to explore the fracture resistance of single-crystal sapphire with different crystal orientations prepared by two processes.…”

Section: Introductionmentioning

confidence: 99%

Fracture Behavior of Single-Crystal Sapphire in Different Crystal Orientations

et al. 2021

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In order to study the anisotropy of fracture toughness and fracture mechanism of single-crystal sapphire, the three-point bending tests and the single-edge V-notch beam (SEVNB) were used to test the fracture toughness of A-plane, C-plane, and M-plane sapphire, which are widely used in the semiconductor, aerospace, and other high-tech fields. Fracture morphology was investigated by a scanning electron microscope and three-dimensional video microscopy. The fracture toughness and fracture morphology of different crystal planes of sapphire showed obvious anisotropy and were related to the loading surfaces. C-plane sapphire showed the maximal fracture toughness of 4.24 MPa·m1/2, and fracture toughness decreases in the order of C-plane, M-plane, and A-plane. The surface roughness is related to the dissipation of fracture energy. The surface roughness of the fracture surface is in the same order as C-plane > M-plane > A-plane. The fracture behavior and morphology of experiments were consistent with the theoretical analysis. C-plane sapphire cleavages along the R-plane with an angle of 57.6 degrees and the rhombohedral twin were activated. M-plane and A-plane sapphire cleavages along their cross-section.

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Mechanical properties of single and polycrystalline α-Al2O3 coatings grown by chemical vapor deposition

Cited by 33 publications

References 25 publications

Fracture Properties of α– and ĸ–Al2O3 Hard Coatings Deposited by Chemical Vapor Deposition

Fracture Properties of α– and ĸ–Al2O3 Hard Coatings Deposited by Chemical Vapor Deposition

Influence of Thermal Degradation on the Mechanical Properties of Coatings [8YSZ/Al2O3]n Subjected to Thermals Cycles

Fracture Behavior of Single-Crystal Sapphire in Different Crystal Orientations

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