High temperature deformation of MoSi2 single crystals with the C11b structure

Umakoshi, Yukichi; Sakagami, Takahide; Hirano, Tôru; Yamane, Toshimi

doi:10.1016/0956-7151(90)90163-b

Cited by 138 publications

(32 citation statements)

References 8 publications

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“…The BDTT has also been lowered by generation of dislocations in the MoSi 2 grains in MoSi 2 -ZrO 2 [26,27] and MoSi 2 -TiC composites [7,27] during processing, where particle-matrix interfaces have acted as sources of dislocations. At 1200 °C and above, more than five independent slip systems, [11] [13,15,18,[21][22][23][24][25] and polycrystalline [14,16,17,28] MoSi 2 deformed at different temperatures and strain rates, chiefly at 10 Ϫ4 s Ϫ1 or slower.…”

Section: Introductionmentioning

confidence: 99%

“…[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. [14] The five most active slip systems reported by Ito et al [15] are {013}͗331͘, {110}͗111͘, {011}͗100͘, {010}͗100͘, and {023}͗100͘.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 99%

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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“…They have good potential for improving gasturbine engine performance. MoSi 2 is one of the most promising candidates for such structural applications because of its high melting point, good oxidation resistance, and superior strength at high temperatures [1][2][3]. MoSi 2 crystallizes in the C11 b structure, which is based on a tetragonal unit cell.…”

Section: Introductionmentioning

confidence: 99%

Fracture behavior and toughness of NbSi2-based single crystals and MoSi2(C11b)/NbSi2(C40) duplex crystals with a single set of lamellae

Hagihara

Nakano

2011

Acta Materialia

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“…35 It was suggested that deformation mechanisms such as the climb of dislocations contribute to the plasticity of MoSi 2 increasingly with increasing temperature above BDTT. Such a plasticity-based mechanism is reported by Umakoshi et al 36 at 1300°C and by Evans et al 35 at temperatures of 1400°C and above. These observations are consistent with the nonlinear P-␦ response observed in the samples tested at temperatures greater than 1300°C.…”

Section: (2) High-temperature Propertiesmentioning

confidence: 77%

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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High temperature deformation of MoSi2 single crystals with the C11b structure

Cited by 138 publications

References 8 publications

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

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

Fracture behavior and toughness of NbSi2-based single crystals and MoSi2(C11b)/NbSi2(C40) duplex crystals with a single set of lamellae

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

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