Determination of the crack-tip toughness in silicon nitride ceramics

被引:14
|
作者
Fuenfschilling, S. [1 ]
Fett, T. [1 ]
Hoffmann, M. J. [1 ]
Oberacker, R. [1 ]
Jelitto, H. [2 ]
Schneider, G. A. [2 ]
机构
[1] Univ Karlsruhe, Inst Keram Maschinenbau, Karlsruhe, Germany
[2] Tech Univ Hamburg, Inst Keram Hochleistungswerkstoffe, Hamburg, Germany
关键词
Stress Intensity Factor; Y2O3; Silicon Nitride; Notch Root Radius; Silicon Nitride Ceramic;
D O I
10.1007/s10853-008-3136-6
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Crack-opening displacements (COD) method was used to measure crack-tip toughness in silicon nitride Si3N4 ceramics containing (Y2O3,MgO) and (Y2O3, Al2O3). The R-curves for these materials were measured in a very stiff test device and four-point bending tests were carried out on notched bars of dimensions. Results for the first microns of crack propagation show that the R-curves raise very steeply reaching saturation already after a few μm crack extension. The semi-elliptical crack shape of Vickers cracks are found to develop in the unloading phase, characterized by the condition of crack-tip toughness at the crack tip after load removal. The crack-tip toughness for (Y2O3,MgO) is 2.33MPa√m and 2.033MPa√m for (Y2O3, Al2O3).
引用
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页码:335 / 338
页数:4
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