In situ bend testing of niobium-reinforced alumina nanocomposites with and without single-walled carbon nanotubes

Thomson, Katherine; Jiang, Dianlu; Lemberg, Joseph; Koester, Kurt J.; Ritchie, Robert O.; Mukherjee, Amiya K.

doi:10.1016/j.msea.2007.05.123

Cited by 10 publications

(9 citation statements)

References 11 publications

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“…In the past, several investigations concerning high-temperature properties (creep, fracture toughness) were performed for Al 2 O 3 ceramics [25,26], as well as refractory ceramics with up to 50% niobium [8,9,19,27,28,29]. In these papers, different damage mechanisms were discussed, e.g., ceramic-metal interface decohesion [8,29], fracture of ceramic particles [29], and retardation of crack propagation by a high-volume fraction of niobium [8,29], as well as the resulting high fracture toughness [9].…”

Section: Introductionmentioning

confidence: 99%

Mechanical High-Temperature Properties and Damage Behavior of Coarse-Grained Alumina Refractory Metal Composites

et al. 2019

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The present study provides the mechanical properties of a new generation of refractory composites based on coarse-grained Al2O3 ceramic and the refractory metals Nb and Ta. The materials were manufactured by refractory castable technology and subsequently sintered at 1600 °C for 4 h. The mechanical properties and the damage behavior of the coarse-grained refractory composites were investigated at high temperatures between 1300 and 1500 °C. The compressive strength is given as a function of temperature for materials with two different volume fractions of the refractory metals Ta and Nb. It is demonstrated that these refractory composites do not fail in a completely brittle manner in the studied temperature range. The compressive strength for all materials significantly decreases with increasing temperature. Failure occurred due to the formation of cracks along the ceramic/metal interfaces of the coarse-grained Al2O3 particles. In microstructural observations of sintered specimens, the formation of tantalates, as well as niobium oxides, were observed. The lower compressive strength of coarse-grained Nb-Al2O3 refractory composites compared to Ta-Al2O3 is probably attributed to the formation of niobium oxides. The formation of tantalates, however, seems to have no detrimental effect on compressive strength.

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Section: Introductionmentioning

confidence: 99%

Mechanical High-Temperature Properties and Damage Behavior of Coarse-Grained Alumina Refractory Metal Composites

et al. 2019

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“…However, alumina-CNT composites are previously reported to have lower hardness as compared to monolithic alumina [10,[20][21][22][23][24][25][26] due to various reasons. Jiang et al reported lower hardness and toughness for alumina + 10 vol.% CNT composite due to the degradation of CNTs during sintering [26].…”

Section: Introductionmentioning

confidence: 99%

The production of advanced fine-grained alumina by carbon nanotube addition

Inam

Peijs

Reece

2011

Journal of the European Ceramic Society

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Alumina and alumina+1vol.% carbon nanotube (CNT) composites were fully densified by spark plasma sintering. Post-sintering heat treatments (1300-1500 •C) were performed to completely oxidize CNTs and then densify the remaining 1 vol.% to produce fine-grained ceramics. The grain size and Vickers hardness of the heat-treated composites were compared with the monolithic alumina sintered without CNT addition. Compared to the initial powder particle size of alumina (D50: 356±74 nm), minimal grain growth (∼450 nm) was observed for the fully dense heat-treated composites. A 25% improvement in Vickers hardness and >10 times finer average grain size were observed for alumina produced by the heat treatment (1300 •C) of alumina+1vol.% CNT composite, compared to alumina sintered without CNTs. Alumina and alumina + 1 vol.% carbon nanotube (CNT) composites were fully densified by spark plasma sintering. Post-sintering heat treatments (1300 -1500 o C) were performed to completely oxidize CNTs and then densify the remaining 1 vol.% to produce fine-grained ceramics. The grain size and Vickers hardness of the heat-treated composites were compared with the monolithic alumina sintered without CNT addition. Compared to the initial powder particle size of alumina (D 50 : 356 nm ± 74 nm), minimal grain growth (~450 nm) was observed for the fully dense heat-treated composites. A 25% improvement in Vickers hardness and >10 times finer average grain size were observed for alumina produced by the heat treatment (1300 o C) of alumina + 1 vol.% CNT composite, compared to alumina sintered without CNTs. Introduction

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“…49) Measurements of the lengths of the cracks emanating from the corners of Vickers indents obtained on cross-sections of alumina-CNT compacts produced by SPS showed that cracks propagating in the pressing direction were shorter than those that were perpendicular to the pressing direction, which was attributed to residual stresses and preferential alignment of CNTs. 49) The achievable level of toughening of ceramics by CNT networks is a matter of debate, as was discussed by Thomson et al 49),50) An interesting effect of reduction of fracture toughness of Al 2 O 3 10 vol.% Nb composites upon the introduction of CNT 50) shows that mutual interaction between the toughening phases should be taken into account in multi-phase composites. Based on refs.…”

Section: Promising Properties Of Composites Achieved By the Network Dmentioning

confidence: 99%

Network distribution of reinforcements in composites produced by sintering: microstructure formation and influence on consolidation behavior and properties

Dudina

Bokhonov

Mukherjee³

2016

J. Ceram. Soc. Japan

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Sintering of powder mixtures is one of the widely used production methods of composite materials. The distribution of the reinforcement phases in these composites is a function of both initial powder structure and sintering conditions. Based on the recent literature and experimental results obtained by the authors, this article discusses a specific type of reinforcement distribution®the network distribution®in composites produced by sintering of powder mixtures. Examples of the influence of networks of different nature on sintering of metal and ceramic matrices are presented for continuous structures composed of carbon nanotubes and quasi-continuous structures of smaller particles located at boundaries between larger particles. The principles of the microstructure formation in composites with networks formed by ceramic particles, particles of metallic glass and carbon nanotubes are analyzed. Unusual properties of composites with metal and ceramic matrices achieved by organizing reinforcements in networks are discussed.

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In situ bend testing of niobium-reinforced alumina nanocomposites with and without single-walled carbon nanotubes

Cited by 10 publications

References 11 publications

Mechanical High-Temperature Properties and Damage Behavior of Coarse-Grained Alumina Refractory Metal Composites

Mechanical High-Temperature Properties and Damage Behavior of Coarse-Grained Alumina Refractory Metal Composites

The production of advanced fine-grained alumina by carbon nanotube addition

Network distribution of reinforcements in composites produced by sintering: microstructure formation and influence on consolidation behavior and properties

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