Thermal behavior, electrical conductivity and microstructure of hot pressed Al2O3/SiC nanocomposites

Parchovianský, Milan; Galusek, Dušan; Švančárek, Peter; Sedláček, Jaroslav; Šajgalı́k, Pavol

doi:10.1016/j.ceramint.2014.06.038

Cited by 43 publications

(29 citation statements)

References 30 publications

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“…When the aggregates are large enough, their motions are no longer restricted by Brownian motion, finally they are pushed ahead of the solidification front. Due to low thermal conductivity of Al 2 O 3np (7.5 W/mK, 800°C; 10 W/mK, 700°C), 24 these particles extensively reduce the temperature and concentration gradients in the solidification front and act as a barrier for a dendrite to grow further, leading to refinement of grains. In Fig.…”

Section: Resultsmentioning

confidence: 99%

Fabrication of nanosized Al₂O₃ reinforced aluminum matrix composites by subtype multifrequency ultrasonic vibration

Chen

Yan

2015

J. Mater. Res.

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O 3np ) reinforced Al7075 composites were fabricated by specially made Al 2 O 3np containing Mg powder and subtype multifrequency ultrasonic vibration. Compared to traditional techniques, Al 2 O 3np was effectively dispersed in the matrix by the novel method. Microstructural studies showed that the addition of Al 2 O 3np caused the grain refinement and that the resultant microstructures of composites depended on the dominant size and degree of Al 2 O 3np clustering. The grain refinement could be mainly attributed to particle pushing mechanisms. Compared to the matrix alloy, the ultimate tensile and compressive strength of the as-cast composite with 1.5 wt% Al 2 O 3np fabricated at 800°C were increased by 59.6% and 42.6%, respectively. Transmission electron microscope analysis showed that high density dislocations and clear interfaces between particles and matrix were present in the grains, suggesting that the superior improvement of mechanical properties can be attributed to dislocation-type strengthening of matrix alloy and load transfer from matrix to hard nanoparticles.

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Section: Resultsmentioning

confidence: 99%

Fabrication of nanosized Al₂O₃ reinforced aluminum matrix composites by subtype multifrequency ultrasonic vibration

Chen

Yan

2015

J. Mater. Res.

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“…Preparation of composites was performed in three phases. The starting procedure consisted of synthesizing 100 g of YAG by the glycine-nitrate combustion method, which is relatively low cost method with fast heating rates, short reaction times, high composition homogeneity and high energy efficiency [13]. In the second phase Al 2 O 3 /YAG powders (AYX_p) were synthesized with different content of YAG (X is 7, 14, 21 and 28 vol.% of YAG in the Al 2 O 3 matrix; p denotes powder).…”

Section: Experimental Procedures 21 Synthesis Of Powdersmentioning

confidence: 99%

“…I and it may be noted that crystals become larger with increase in calcination temperature. Based on the literature data [13] it is assumed that the YAG powder with smallest crystalline size is much more sinterable with Al 2 O 3 particles. Namely, literature data [13,14] have shown that although pinning efficiency of large particles of second phase was high, low pinning efficiency of single nanoparticles was only partially compensated by their number.…”

Section: Sample Characterizationmentioning

confidence: 99%

“…Based on the literature data [13] it is assumed that the YAG powder with smallest crystalline size is much more sinterable with Al 2 O 3 particles. Namely, literature data [13,14] have shown that although pinning efficiency of large particles of second phase was high, low pinning efficiency of single nanoparticles was only partially compensated by their number. Individual nanoparticles were swallowed by growing grains and were often located in intragranular positions [13,14].…”

Section: Sample Characterizationmentioning

confidence: 99%

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Structural, morphological and electrical properties of alumina/YAG composites as solid electrolyte for IT - SOFC

Egelja¹,

Pašalić²,

Dodevski³

et al. 2018

SCI SINTER

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Alumina/YAG composites (AYX_t) with high relative density (99.2 %TD) were successfully obtained by mixing commercial alumina powder with different volume fractions of yttrium aluminium garnet (Y 3 Al 5 O 12-YAG; 7, 14, 21 and 28). YAG was synthetized by nitrate glycine reaction in the form of precursor powder. Polycrystalline YAG powder was obtained by calcination at 950 °C for 2 h. Additionally, obtained compositions were characterized by XRD, SEM, EDX and electrochemical impedance spectroscopy. By XRPD analysis was found that the particle size of YAG powders lies in the nanometric range (being lower than 35 nm). By SEM microphotographs of composites were confirmed the formation of a conductive path consisting from mutually interconnected YAG particles. This was confirmed by the electrochemical impedance spectroscopy. The highest electrical conductivity of grain (κ g) and grain boundary (κ gb) at 700 ºC amounted to 2.22×10-2 Ω-1 cm-1 and 9.44×10-3 Ω-1 cm-1 , respectively, was measured in the composite containing 21 vol% of YAG.

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“…The addition of SiC particles caused moderate increase in thermal conductivity of Alumina composites, which are good options for high‐temperature structures, refractories, gas radiant burners, and cutting tools applications . Al 2 O 3 ‐ up to 30 wt% SiC composites regarding to the higher hardness and fracture toughness used for machining applications .…”

Section: Introductionmentioning

confidence: 99%

Investigation of production parameters in fracture behavior of hot‐pressed Al₂O₃–SiC/graphite fibrous monolithic ceramics: Fibers orientation and cell boundary fraction

Akbari

Kakroudi

Shahedifar

2019

Int J Applied Ceramic Tech

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Fibrous monoliths (FMs) exhibit graceful failure in flexure and have higher toughness values. In this research, a mixture of Al 2 O 3 and SiC as the core and graphite as the shell material of fibers were produced by extrusion-molding technique and after aligning along intended directions (0°, 90°, and 0°/90°) were sintered using the hot-pressing method at the temperature of 1500°C under pressure of 35 MPa for 1 hour. The significance of fibers orientation angle and the cell to cell boundary volume ratio in defining the fracture behavior of the FMs was detected.Because of the extensive crack interactions with graphite cell boundary such as crack deflection and delamination, with increasing cell boundary content from 25 to 30 vol%, the fracture toughness was enhanced. The highest flexural strength (184.8 ± 0.61 MPa) obtained from samples with 0°fibers orientation compared to 0°/90°. Since in the transverse plies (layers with 90°aligning), the properties of matrix phase are dominant, hence the strength in specimens with 0°/90°fibers orientation decreased considerably due to weak graphite matrix phase. In addition, the fracture toughness value increased up to 8.35 ± 0.74 MPa·m 1/2 for the unidirectional architecture of (0°) in comparison with cross-ply (0°/90°) architecture.

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Thermal behavior, electrical conductivity and microstructure of hot pressed Al2O3/SiC nanocomposites

Cited by 43 publications

References 30 publications

Fabrication of nanosized Al₂O₃ reinforced aluminum matrix composites by subtype multifrequency ultrasonic vibration

Fabrication of nanosized Al₂O₃ reinforced aluminum matrix composites by subtype multifrequency ultrasonic vibration

Structural, morphological and electrical properties of alumina/YAG composites as solid electrolyte for IT - SOFC

Investigation of production parameters in fracture behavior of hot‐pressed Al₂O₃–SiC/graphite fibrous monolithic ceramics: Fibers orientation and cell boundary fraction

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Thermal behavior, electrical conductivity and microstructure of hot pressed Al2O3/SiC nanocomposites

Cited by 43 publications

References 30 publications

Fabrication of nanosized Al2O3 reinforced aluminum matrix composites by subtype multifrequency ultrasonic vibration

Fabrication of nanosized Al2O3 reinforced aluminum matrix composites by subtype multifrequency ultrasonic vibration

Structural, morphological and electrical properties of alumina/YAG composites as solid electrolyte for IT - SOFC

Investigation of production parameters in fracture behavior of hot‐pressed Al2O3–SiC/graphite fibrous monolithic ceramics: Fibers orientation and cell boundary fraction

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Product

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Fabrication of nanosized Al₂O₃ reinforced aluminum matrix composites by subtype multifrequency ultrasonic vibration

Fabrication of nanosized Al₂O₃ reinforced aluminum matrix composites by subtype multifrequency ultrasonic vibration

Investigation of production parameters in fracture behavior of hot‐pressed Al₂O₃–SiC/graphite fibrous monolithic ceramics: Fibers orientation and cell boundary fraction