Carbon Additions to Molybdenum Disilicide: Improved High‐Temperature Mechanical Properties

Maloy, Stuart A.; Heuer, A. H.; Lewandowski, John J.; Petrovic, J. J.

doi:10.1111/j.1151-2916.1991.tb06829.x

Cited by 158 publications

(44 citation statements)

References 2 publications

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“…In addition to alloying studies, extensive composite studies have been carried out. Addition of C is seen to improve the oxidation resistance [21]. This is reported to be due to the removal of the siliceous grain boundary.…”

Section: Introductionmentioning

confidence: 95%

Improved ductility and oxidation resistance in Nb and Al co-substituted MoSi2

Dasgupta

Umarji

2008

Intermetallics

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Section: Introductionmentioning

confidence: 95%

Improved ductility and oxidation resistance in Nb and Al co-substituted MoSi2

Dasgupta

Umarji

2008

Intermetallics

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“…In recent years, applications have been proposed or are being attempted in hot-end components of aerospace gas turbines, diesel engine glow plugs, and molten-metal lances. [1] Having being projected as a material for high-temperature structural applications, the thrust of research on MoSi 2 has been on improving the high-temperature mechanical properties [2][3][4][5][6][7][8][9][10][11][12] and establishing a comprehensive understanding of deformation mechanisms. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] Single-crystal MoSi 2 has been found to plastically deform even at room temperature [13] in relatively "soft" orientations away from [001], such as [110], [201], or [0 15 1], while polycrystalline MoSi 2 cannot deform without cracking until 1000 °C, as only four independent slip systems have been found to be active at or below 1000 °C.…”

Section: Introductionmentioning

confidence: 99%

High-temperature deformation behavior of coarse- and fine-grained MoSi2 with different silica contents

Mitra

Prasad

Kumari

et al. 2003

Metall Mater Trans A

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The elevated-temperature deformation behavior of polycrystalline molybdenum disilicide (MoSi 2 ), in the range of 1000 °C to 1350 °C at the strain rates of 10 Ϫ3 , 5 ϫ 10 Ϫ4 , or 10 Ϫ4 s Ϫ1 , has been studied. The yield strength, post-yield flow behavior comprising strain hardening and serrations, as well as some of the deformation microstructures of reaction-hot-pressed (RHP) MoSi 2 samples, processed by hot pressing an elemental Mo ϩ Si powder mixture and having a grain size of 5 mm and oxygen content of 0.06 wt pct, have been compared with those of samples prepared by hot pressing of commercial-grade Starck MoSi 2 powder, with a grain size of 27 mm and oxygen content of 0.89 wt pct. While the fine-grained RHP MoSi 2 samples have shown higher yield strength at relatively lower temperatures and higher strain rates, the coarse-grained Starck MoSi 2 has a higher yield at decreasing strain rates and higher temperatures. The work-hardening or softening characteristics are dependent on grain size, temperature, and strain rate. Enhanced dislocation activity and dynamic recovery, accomplished by arrangement of dislocations in low-angle boundaries, characterize the deformation behavior of fine-grained RHP MoSi 2 at a temperature of 1200 °C and above and are responsible for increased uniform plastic strain with increasing temperature. The silica content appears to be less effective in degrading the high-temperature yield strength if the grain size is coarse, but leads to plastic-flow localization and strain softening in Starck MoSi 2 . Serrated plastic flow has also been observed in a large number of samples, mostly when deformed at specific combinations of strain rates and temperatures.

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“…It may then be possible that by reinforcing with both TiB 2 and SiC, minimization (if not elimination) of pesting at intermediate temperatures and retention of high-temperature strength and creep resistance can be achieved simultaneously. Previous work by the authors has shown that double reinforcement of TiB 2 and SiC increased the room-temperature hardness more than single reinforcement of either TiB 2 or SiC. Dry-sliding wear experiments also showed that the wear rate in the mild-wear region is lower in double reinforcement composites of MoSi 2 .…”

Section: Introductionmentioning

confidence: 53%

“…Furthermore, the appearance of grain-boundary cavities can also be seen, which is found to increase with increasing temperature. Maloy et al 2 reported an intergranular type of fracture at all temperatures for the monolithic MoSi 2 due to the presence of a siliceous intergranular phase. But, in the present study the transition to intergranular is found to occur only above 1300°C.…”

Section: (2) Fractographymentioning

confidence: 99%

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Effect of Double Reinforcements on Elevated‐Temperature Strength and Toughness of Molybdenum Disilicide

Tantry

Ramasesha

Lee

et al. 2004

Journal of the American Ceramic Society

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Flexural strength and fracture toughness of molybdenum disilicide and its composites with 10 wt% TiB 2 and 10 wt% TiB 2 ؉ 10 wt% SiC, synthesized by the hot-pressing technique, were evaluated as a function of temperature, ranging from ambient temperature to 1600°C. Results show that the composites have higher strength and slightly lower toughness as compared with monolithic MoSi 2 at room temperature. At high temperatures, the composites exhibit higher strength as well as higher toughness vis-à-vis monolithic MoSi 2 . Among the composites, the double reinforcement of SiC and TiB 2 was found to be more effective in improving the mechanical properties. A transition from brittle to ductile behavior was observed at temperatures greater than 1300°C for all materials tested. The high-temperature mechanical behavior was found to be significantly influenced by the flow of an intergranular glassy phase and the attendant cavity nucleation and growth along the grain boundaries. Micromechanisms responsible for the ambient as well as the elevated-temperature property improvement in composites are discussed with the aid of fractography.

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Carbon Additions to Molybdenum Disilicide: Improved High‐Temperature Mechanical Properties

Cited by 158 publications

References 2 publications

Improved ductility and oxidation resistance in Nb and Al co-substituted MoSi2

Improved ductility and oxidation resistance in Nb and Al co-substituted MoSi2

High-temperature deformation behavior of coarse- and fine-grained MoSi2 with different silica contents

Effect of Double Reinforcements on Elevated‐Temperature Strength and Toughness of Molybdenum Disilicide

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