https://scholars.lib.ntu.edu.tw/handle/123456789/425041
標題: | Microstructural design of silicon nitride with improved fracture toughness: I, Effects of grain shape and size | 作者: | Becher P.F. Sun E.Y. Plucknett K.P. Alexander K.B. Hsueh C.-H. Lin H.-T. Waters S.B. Westmoreland C.G. Kang E.-S. Hirao K. Brito M.E. CHUN-HWAY HSUEH |
公開日期: | 1998 | 卷: | 81 | 期: | 11 | 起(迄)頁: | 2821-2830 | 來源出版物: | Journal of the American Ceramic Society | 摘要: | The use of self-reinforcement by larger elongated grains in silicon nitride ceramics requires judicious control of the microstructure to achieve high steady-state toughness and high fracture strength. With a distinct bimodal distribution of grain diameters, such as that achieved by the addition of 2% rodlike seeds, the fracture resistance rapidly rises with crack extension to steady-state values of up to 10 MPa¡Pm 1/2 and is accompanied by fracture strengths in excess of 1 GPa When the generation of elongated reinforcing grains is not regulated, a broad grain diameter distribution is typically generated. While some toughening is achieved, both the plateau (steady-state) toughness and the R-curve response suffer, and the fracture strength undergoes a substantial reduction. Unreinforced equiaxed silicon nitride exhibits the least R-curve response with a steady-state toughness of only 3.5 MPa¡Pm 1/2 coupled with a reduced fracture strength. |
URI: | https://scholars.lib.ntu.edu.tw/handle/123456789/425041 | ISSN: | 00027820 |
顯示於: | 材料科學與工程學系 |
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