Influence of annealing on the mechanical properties of SiC–Si composites with sub-micron SiC microstructures

Wilhelm, Matthias; Wruss, W.

doi:10.1016/s0955-2219(99)00275-7

Cited by 14 publications

(7 citation statements)

References 12 publications

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“…Therefore, the density of ceramic compacts was reduced at higher contents of Si and/or C. On the other hand, since the interfaces between SiC and Si as well as the brittle free silicon phase are preferential paths for fracture, the presence of free silicon is detrimental for production of SiC ceramics [18]. Additionally, the strength and creep resistance deteriorate at temperatures above 1400 • C due to existing free silicon [11]. Microcracks were found within some of the free silicon phase at high amount of Si in the starting material (see Figure 9(b)).…”

Section: Discussionmentioning

confidence: 99%

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Densification and Microstructural Evolutions during Reaction Sintering of SiC-Si-C Powder Compacts

Asgharzadeh

Ehsani

2011

ISRN Materials Science

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Porous SiC-Si-C ceramics were produced by reaction sintering (RS) of silicon carbide, silicon, and carbon powder compacts in the temperature range of 1400–1600°C. The effects of chemical composition of the starting powder, initial SiC particle size, and reaction sintering temperature and duration on the densification and microstructure of ceramic materials were studied. The results showed that increasing the amount of Si and/or C powders in the starting powder mixture had a detrimental influence on the densification of ceramic material as a result of higher amount of remained silicon and carbon phases in the ceramic specimen. Increasing the RS temperature also degraded densification due to the melting of Si and coming out of it from compact during heating. Nevertheless, densification was improved by increasing the RS duration. Using nanometric SiC particles in the starting powder mixture improved the densification compared to that of micrometric ones especially at longer RS processing duration.

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Section: Discussionmentioning

confidence: 99%

“…Residual pores and space not occupied by silicon carbide are filled with liquid silicon. It is well known [11,12] that one limiting factor to obtain SiC parts with high strength is the amount of free silicon in the composites since the brittle free silicon phase and interfaces between SiC and Si are preferential paths for fracture.…”

Section: Introductionmentioning

confidence: 99%

Densification and Microstructural Evolutions during Reaction Sintering of SiC-Si-C Powder Compacts

Asgharzadeh

Ehsani

2011

ISRN Materials Science

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“…However, research on mechanical properties of RB-SiC ceramics, up to date, mainly focus on the influence of microstructure [27,28], annealing treatment [29,30] and carbon perform [31] during the material fabrication. These investigations were generally conducted at room temperature with a conventional measuring technique.…”

Section: Introductionmentioning

confidence: 99%

Characterization of hardness, elastic modulus and fracture toughness of RB-SiC ceramics at elevated temperature by Vickers test

Rao

Zhang

Luo

et al. 2019

Materials Science and Engineering: A

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In this paper, mechanical properties of RB-SiC ceramics, such as hardness, elastic modulus and fracture toughness, are characterized through indentation technique using a Vickers indenter at elevated temperatures ranging from room temperature to 1200 °C realized by laser heating.. The indentation size effect, load-displacement curves and relationship between crack length and applied load are studied in order to determine hardness, elastic modulus and fracture toughness accurately. The results show that the Meyer's index and Vickers hardness decrease with the increase temperature. It indicates that the permanent plastic deformation of RB-SiC ceramics is mainly responsible for the indentation size effect and the reduction of hardness at elevated temperature. Both material softening and plastic deformation will contribute to the indentation creep at elevated temperature as shown in the load-displacement curves. The elastic modulus decreases with the increase of temperature due to increase of contact depth as a result of less elastic recovery. In the indentation test for calculating fracture toughness, only radial-median cracks are identified by the relationship between crack length and applied load at all temperatures, although the fracture mode observed at the indent corner changes from transgranular at room temperature to intergranular at elevated temperature. As more energy is consumed by intergranular facture and cracking-healing takes place due to oxidation, only short crack length appears in the indentation test which implies an increase of fracture toughness with the increase of temperature. However, this tendency has an exception at the highest temperature of 1200℃. This is because the free Si softening in RB-SiC specimen fails to resist crack propagation at extremely high temperature. Consequently, the crack length increases again which leads to the increase of the calculating fracture toughness at the highest temperature. These variations of hardness, elastic modulus and fracture toughness with temperatures will account for the possible change of material removal regimes occurred in some thermal-involved hybrid machining of RB-SiC ceramics.

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“…The inclusion of glassy [1] or metallic [19] secondary phases has been shown to decrease the brittleness and increase the fracture toughness value of ceramics. Newer processing techniques, such as reaction bonding, have been used to manufacture ceramics with increased fracture toughness while minimally compromising other material properties, such as density and hardness, compared to similar sintered ceramics [20][21][22][23][24][25]. In this study, a variety of reaction-bonded ceramic composites are compared to several pressureless-sintered ceramics to investigate the effect of microstructure on the fracture toughness value.…”

Section: Introductionmentioning

confidence: 99%

The rate-dependent fracture toughness of silicon carbide- and boron carbide-based ceramics

Pittari

Subhash

Zheng

et al. 2015

Journal of the European Ceramic Society

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Influence of annealing on the mechanical properties of SiC–Si composites with sub-micron SiC microstructures

Cited by 14 publications

References 12 publications

Densification and Microstructural Evolutions during Reaction Sintering of SiC-Si-C Powder Compacts

Densification and Microstructural Evolutions during Reaction Sintering of SiC-Si-C Powder Compacts

Characterization of hardness, elastic modulus and fracture toughness of RB-SiC ceramics at elevated temperature by Vickers test

The rate-dependent fracture toughness of silicon carbide- and boron carbide-based ceramics

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