High Temperature Fatigue Crack Growth in Silicon Nitride and Role of SCC.

氮化硅中的高温疲劳裂纹扩展和 SCC 的作用。

• 批准号: 02650054
• 负责人: MUTOH Yoshiharu
• 金额: $ 1.22万
• 依托单位: Nagaoka University of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02650054/
• 关键词: Ceramics; Silicon Nitride; Fatigue Crack; Crack Growth Rate; Bridging; High Temperature; Stress Corrosion Cracking; 応力波形

(1) During crack growth in silicon nitride, microcracking on weak grain boundaries and subsequently bridging occur. The acceleration of crack growth rate in cyclic fatigue compared to the case in static fatigue will result from that the bridges are fractured and removed by cyclic deformation.(2) The crack growth behavior in silicon nitride is strongly affected by the history of crack growth due to formation of the bridges. So, the crack growth rate can not be given uniquely by the applied K-value.(3) The crack tip stress intensity factor K-tip, which is given the actual stress field at the crack tip country on the effect of stress shield by the bridging, can be estimated by reducing the K at crack tip from the measured crack mouth opening displacement. The unique relationship between K-tip and crack growth rate is found independent of the history of crack growth.(4) The orientation of silicon nitride grain in the tensile direction in the high strain region at the crack tip was observed at the temperatures over 1200ﾟC, which corresponds to the softening point of the grain boundary glass phase. The transition of fracture mechanism was observed from brittle intergranular to ductile pulling out of grain with shear deformation of boundary glass phase.

（1）在硝酸硅中，与静态疲劳相比，较弱的晶粒型和随后的桥梁会在循环疲劳中发生。由于桥梁的形成，裂纹的强烈生长无法通过施加的k值唯一地给予（3）裂纹尖端应力强度K-TIP是通过测量的裂纹嘴开口显示，可以通过在裂纹裂纹生长速度上降低裂纹的裂纹尖端的效果。在1200°C的温度下观察到，这对应于软化阶段。

项目成果

Y. Motoh, M. Takahashi, T. Oikawa, H. Okamoto: "Fatigue Crack Growth of Long and Short Cracks in Silicion Nitride" Fatigue of Advanced Materials. Pergamon Press. (1991)

Y. Motoh、M. Takahashi、T. Oikawa、H. Okamoto：“氮化硅中长裂纹和短裂纹的疲劳裂纹扩展”先进材料的疲劳。

Y.Mutoh,et al.: "Fatigue Crack Growth of Long and Short Cracks in Silicon Nitride" Fatigue of Advanced Materials. (1991)

Y.Mutoh 等人：“氮化硅中长裂纹和短裂纹的疲劳裂纹生长”先进材料的疲劳。

Y.Mutoh,et al.: "BrittleーtoーDuctile Transition in Silion Nitride" Fracture Mechanics of Ceramics. 10. (1992)

Y. Mutoh 等人：“氮化硅中的脆性到延性转变”陶瓷断裂力学 10。(1992)

高橋,武藤: "数種のセラミックスの静疲労および繰返し疲労き裂伝ぱ特性" 日本機械学会論文集. 57. 2615-2621 (1991)

Takahashi, Muto：“几种陶瓷的静态疲劳和循环疲劳裂纹扩展特性”，日本机械工程师学会汇刊 57. 2615-2621 (1991)。

M.Takahashi,Y.Mutoh,et al.: "Effect of Surface Finish on Fatigue Strength in Silicon Nitride" Mechanical Behavior of Materials - VI. 2. 371-376 (1991)

M.Takahashi,Y.Mutoh,et al.：“表面处理对氮化硅疲劳强度的影响”材料的机械行为 - VI。