Mechanical Properties of Single-Crystal α-Si3N4 |
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| Authors: | Ivar E. Reimanis&# ,Hisayuki Suematsu&# ,John J. Petrovic&# ,T. E. Mitchell&# |
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| Affiliation: | Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, Colorado 80401;National Institute for Research in Inorganic Materials, 1-1 Namiki, Tsukuba, Ibarki 305, Japan;Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 |
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| Abstract: | Single crystals of α-Si3N4 several millimeters in diameter and several millimeters long have been grown by chemical vapor deposition. Some of the microstructural and mechanical properties have been evaluated using X-ray diffracometry, optical and transmission electron microscopy, and high-temperature microhardness testing. The crystallographic growth direction determines the quality of the crystals, including the density of internal microcracks and the nature and quantity of special boundaries. The measurement of crack lengths associated with microindentations has shown that cleavage in α-Si3N4 is relatively isotropic. Finally, indentation fracture toughness values agree well with theoretical predictions based on recent bond-energy calculations. |
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