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Electron Microscopy in Optimizing Microstructure and Mechanical Properties of Hot-Pressed Silicon Carbide

Published online by Cambridge University Press:  02 July 2020

X.F. Zhang
Affiliation:
Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA , 94720
M.E. Sixta
Affiliation:
Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA , 94720
Q. Yang
Affiliation:
Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA , 94720
D. Chen
Affiliation:
Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA , 94720
R.O. Ritchie
Affiliation:
Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA , 94720
L.C. De Jonghe
Affiliation:
Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA , 94720
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Abstract

SiC, as one of the most promising candidate ceramics for high temperature structural applications, offers many intrinsic advantages, including high melting temperatures, low density, and high elastic modulus. However, the use of SiC to date has been severely limited by its poor fracture toughness (∽ 2-3 MPa√m for commercially available materials) and crack-growth resistance. Our study focuses on the development of silicon carbide as a potentially tough, high-temperature, and damage-tolerant material. The approaches include identifying roles of sintering additives in modifying grain morphology, effects of post-annealing on grain boundary phases, and possibility in introducing nanoscale precipitates in SiC grains. Central in these efforts is structural characterization using state-of-the-art electron microscopy.

The first success was in situtoughening the SiC, by hot pressing in the presence of A1, B and C additions. Elongated and interlocked grains were developed surrounded by an Al-containing amorphous grain boundary film.

Type
Novel Microscopy Assisted Ceramic Developments in Materials Scienceand Nanotechnology (Organized by P. Gai and J. Lee)
Copyright
Copyright © Microscopy Society of America 2001

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References

1.Cao, J.J. et al., J. Am. Ceram. Soc, 79 (1996)461CrossRefGoogle Scholar
2.Zhang, X.F. et al., J. Am. Ceram. Soc, 83 (2000)2813CrossRefGoogle Scholar
3.Zhang, X.F. et al., Defect and Diffusion Forum, 186187 (2000)45Google Scholar
4. This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, Materials Sciences Division of the U.S. Department of Energy under Contract No. DE-AC03- 76SF0098.Google Scholar