Pinning effect of reactive elements on structural stability and adhesive strength of environmental sulfur segregation on Al2O3/NiAl interface

Zhang, Zifang; Hu, Cheng Chao; Chen, H.; He, Jian

doi:10.1016/j.scriptamat.2020.07.038

Cited by 8 publications

(3 citation statements)

References 29 publications

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“…Another interesting system is Al 2 O 3 –NiAl [ 20 , 21 , 22 ] or NiAl/TiC–Al 2 O 3 [ 23 ]. Combining these ceramics with intermetallic phases allows producing composites for high-temperature and chemical-resistant applications.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Al2O3 Samples and NiAl–Al2O3 Composite Consolidated by Pulse Plasma Sintering

et al. 2021

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The paper describes an investigation of Al2O3 samples and NiAl–Al2O3 composites consolidated by pulse plasma sintering (PPS). In the experiment, several methods were used to determine the properties and microstructure of the raw Al2O3 powder, NiAl–Al2O3 powder after mechanical alloying, and samples obtained via the PPS. The microstructural investigation of the alumina and composite properties involves scanning electron microscopy (SEM) analysis and X-ray diffraction (XRD). The relative densities were investigated with helium pycnometer and Archimedes method measurements. Microhardness analysis with fracture toughness (KIC) measures was applied to estimate the mechanical properties of the investigated materials. Using the PPS technique allows the production of bulk Al2O3 samples and intermetallic ceramic composites from the NiAl–Al2O3 system. To produce by PPS method the NiAl–Al2O3 bulk materials initially, the composite powder NiAl–Al2O3 was obtained by mechanical alloying. As initial powders, Ni, Al, and Al2O3 were used. After the PPS process, the final composite materials consist of two phases: Al2O3 located within the NiAl matrix. The intermetallic ceramic composites have relative densities: for composites with 10 wt.% Al2O3 97.9% and samples containing 20 wt.% Al2O3 close to 100%. The hardness of both composites is equal to 5.8 GPa. Moreover, after PPS consolidation, NiAl–Al2O3 composites were characterized by high plasticity. The presented results are promising for the subsequent study of consolidation composite NiAl–Al2O3 powder with various initial contributions of ceramics (Al2O3) and a mixture of intermetallic–ceramic composite powders with the addition of ceramics to fabricate composites with complex microstructures and properties. In composites with complex microstructures that belong to the new class of composites, in particular, the synergistic effect of various mechanisms of improving the fracture toughness will be operated.

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Section: Introductionmentioning

confidence: 99%

Characterization of Al2O3 Samples and NiAl–Al2O3 Composite Consolidated by Pulse Plasma Sintering

et al. 2021

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“…The favorable effect of Al 2 O 3 on the hardness of the NiAl matrix composite was also demonstrated in the study conducted by Udhayabanu et al [39], where the composite with 10 vol.% Al 2 O 3 was obtained by a combination of reactive milling and subsequent SPS. The composite hardness value of 7.6 GPa was found to result from the presence of nanometric particles of Al 2 O 3 [9]. The hardness of the composites with a similar structure, but containing boron instead of alumina distributed in the NiAl matrix, ranged from 10.3 GPa to 12.6 GPa, and increased with increasing boron content [17].…”

Section: Characterization Of Nial-al2o3 Samples After Pps Consolidationmentioning

confidence: 95%

“…Ceramics are combined with metals and intermetallic materials to produce composites. Various metals are used, such as V, Mo, Cu, Ni, Ti, or Fe [1][2][3][4][5][6][7], along with intermetallics such as NiAl [8,9] or Ni 3 Al [10]. Such materials have been developed because of their desirable properties.…”

Section: Introductionmentioning

confidence: 99%

Pulse Plasma Sintering of NiAl-Al2O3 Composite Powder Produced by Mechanical Alloying with Contribution of Nanometric Al2O3 Powder

et al. 2022

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NiAl-Al2O3 composites, fabricated from the prepared composite powders by mechanical alloying and then consolidated by pulse plasma sintering, were presented. The use of nanometric alumina powder for reinforcement of a synthetized intermetallic matrix was the innovative concept of this work. Moreover, this is the first reported attempt to use the Pulse Plasma Sintering (PPS) method to consolidate composite powder with the contribution of nanometric alumina powder. The composite powders consisting of the intermetallic phase NiAl and Al2O3 were prepared by mechanical alloying from powder mixtures containing Ni-50at.%Al with the contribution of 10 wt.% or 20 wt.% nanometric aluminum oxide. A nanocrystalline NiAl matrix was formed, with uniformly distributed Al2O3 inclusions as reinforcement. The PPS method successfully consolidated NiAl-Al2O3 composite powders with limited grain growth in the NiAl matrix. The appropriate sintering temperature for composite powder was selected based on analysis of the grain growth and hardness of Al2O3 subjected to PPS consolidation at various temperatures. As a result of these tests, sintering of the NiAl-Al2O3 powders was carried out at temperatures of 1200 °C, 1300 °C, and 1400 °C. The microstructure and properties of the initial powders, composite powders, and consolidated bulk composite materials were characterized by SEM, EDS, XRD, density, and hardness measurements. The hardness of the ultrafine-grained NiAl-Al2O3 composites obtained via PPS depends on the Al2O3 content in the composite, as well as the sintering temperature applied. The highest values of the hardness of the composites were obtained after sintering at the lowest temperature (1200 °C), reaching 7.2 ± 0.29 GPa and 8.4 ± 0.07 GPa for 10 wt.% Al2O3 and 20 wt.% Al2O3, respectively, and exceeding the hardness values reported in the literature. From a technological point of view, the possibility to use sintering temperatures as low as 1200 °C is crucial for the production of fully dense, ultrafine-grained composites with high hardness.

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Progress on high-temperature protective coatings for aero-engines

Guo,

He,

Chen

et al. 2023

Surf. Sci. Tech.

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Aero-engine is a key part of aircraft, the operating temperature of which is being pushed to unprecedented levels for higher engine efficiency and performance. To accomplish higher gas-inlet temperature of aero-engines, applying thermal barrier coatings (TBCs) on hot-section metallic components, or even replacing some of the metallic components in aero-engines with ceramic-matrix composites (CMCs) and applying environmental-barrier coatings (EBCs) on them, are effective methods and have been widely accepted. On the other hand, increasing aero-engines operating temperature causes the aircraft more easily be detected, thus stealth coatings are necessary for engines. Except the hottest part in aero-engines, other parts may not need TBCs or EBCs due to the relatively low operating temperature, but they still need protection from oxidation and corrosion. Hence, corrosion-resistant coatings are essential. In this paper, the latest progress of the above high-temperature protective coatings, i.e., TBCs, EBCs, stealth coatings and corrosion-resistant coatings is reviewed, mainly including their materials, fabrication technologies and performance. In addition, due to the harsh operating environment, these protective coatings face many threats such as calcia-magnesia-aluminosilicates (CMAS) attack, causing premature failure of the coatings, which is also concerned in this paper. The work would provide a comprehensive understanding on the high-temperature protective coatings in aero-engines and guidance for developing advanced protective coatings for next-generation aero-engines.

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Pinning effect of reactive elements on structural stability and adhesive strength of environmental sulfur segregation on Al2O3/NiAl interface

Cited by 8 publications

References 29 publications

Characterization of Al2O3 Samples and NiAl–Al2O3 Composite Consolidated by Pulse Plasma Sintering

Characterization of Al2O3 Samples and NiAl–Al2O3 Composite Consolidated by Pulse Plasma Sintering

Pulse Plasma Sintering of NiAl-Al2O3 Composite Powder Produced by Mechanical Alloying with Contribution of Nanometric Al2O3 Powder

Progress on high-temperature protective coatings for aero-engines

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