ZrO2-Reinforced MoSi2 Matrix Composites

Petrovic, J. J.; Honnell, R.E.; Mitchell, T. E.; Wade, R.K.; McClellan, K. J.

doi:10.1002/9780470313848.ch2

Cited by 46 publications

(5 citation statements)

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“…Several attempts to improve the low-temperature fracture toughness of MoSi 2 by forming composite materials have been made. The addition of ceramic particles or whiskers such as SiC [32] or ZrO 2 [33] inhibits fracture and increases the fracture toughness to a level achieved by incorporation of a ductile second phase. For example, Mo in MoSi 2 [34] increases the fracture toughness (up to %10 MPa m 1a2 ).…”

Section: Molybdenum Disilicide and Its Substitutional Alloysmentioning

confidence: 99%

Modeling Brittle and Ductile Behavior of Solids from First-Principles Calculations

Waghmare

Kaxiras

Duesbery³

2000

phys. stat. sol. (b)

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A broad classification of solids in terms of their mechanical behavior would characterize them as brittle or ductile. While there is no doubt that ultimately this behavior is due to processes at the atomistic level, the link between these processes and their macroscopic manifestation is difficult to establish. Phenomenological theories that try to address this link must rely on microscopic parameters, the values of which are beyond their scope. Here we review recent efforts to employ firstprinciples electronic structure calculations in order to determine important physical quantities which, in conjunction with phenomenological theories, can provide insight into brittle versus ductile behavior. We apply this approach to cases of intrinsic interest, such as silicon, the prototypical brittle solid, as well as in cases of practical interest, such as the improvement of ductility in molybdenum disilicide, a material of potential usefulness in improved turbine blades. Current indications are that this combination of techniques can serve as powerful qualitative predictive tool for the dependence of mechanical behavior on the microscopic structure and chemical composition of a solid.

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Section: Molybdenum Disilicide and Its Substitutional Alloysmentioning

confidence: 99%

Modeling Brittle and Ductile Behavior of Solids from First-Principles Calculations

Waghmare

Kaxiras

Duesbery³

2000

phys. stat. sol. (b)

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“…Sun et al reported that the bending strength of MoSi 2 increased from 202 MPa to 389 and 448 MPa with the addition of SiC w and TiC w , respectively [9]. Petrovic et al reported that the fracture toughness of MoSi 2 increased from 3 to 8 MPa m 1/2 with the addition of ZrO 2 particulates [10].…”

Section: Introductionmentioning

confidence: 98%

Synthesis, microstructure and properties of MoSi 2 –5 vol%Al 2 O 3 composites

Wang

Feng

Niu

et al. 2014

Ceramics International

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“…On the other hand, compressive loading inhibits failure by void growth and linkage, while plastic deformation takes place as the yield stress is reached. 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%

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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ZrO2-Reinforced MoSi2 Matrix Composites

Cited by 46 publications

References 0 publications

Modeling Brittle and Ductile Behavior of Solids from First-Principles Calculations

Modeling Brittle and Ductile Behavior of Solids from First-Principles Calculations

Synthesis, microstructure and properties of MoSi 2 –5 vol%Al 2 O 3 composites

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

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