Nano-Fractography Study of Fatigue Crack Growth under Service Loading in Ceramics

陶瓷使用载荷下疲劳裂纹扩展的纳米断口研究

• 批准号: 09450051
• 负责人: SUGETA Atsushi
• 金额: $ 8万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450051/
• 关键词: Fatigue Strength; Fatigue Crack Growth; Ceramics; Crack Closure; Small Crack; Service Loading; KィイD2effィエD2; Crack Initiation

In order to investigate cyclic fatigue crack growth behavior of a gas-pressure-sintered silicon nitride, SiィイD23ィエD2NィイD24ィエD2 and SiィイD23ィエD2NィイD24ィエD2 /BN compound sintered ceramics under constant and variable amplitude load sequences, fatigue crack growth tests were carried out using compact type (CT) specimens. Crack length and macroscopic crack closure were measured using an unloading elastic compliance method. The grain interlocking was observed around crack wake in all fatigue test conditions, which implied fatigue crack growth of this material was associated with progressive degradation of the grain interlocking by cyclic loading. Fatigue crack growth rate, da/dn, under constant amplitude loading was controlled not only by maximum stress intensity factor, KィイD2maxィエD2, but also stress amplitude, while KィイD2maxィエD2 was the most important factor in cyclic fatigue crack growth. The overload and high-level load excursion produced the acceleration of fatigue crack growth and the decrease of crack closure point under low-level loading. This decrease was thought to result from much severer crash or frictional wear of grain interlocking and the crack closure could explain the acceleration behavior qualitatively.

为了研究常压烧结氮化硅、氮化硅D23陶瓷D2 N陶瓷D24陶瓷D2和氮化硅D23陶瓷D2 N陶瓷D24陶瓷D2 /BN复合烧结陶瓷在恒幅和变幅载荷下的循环疲劳裂纹扩展行为，采用致密型（CT）试样进行了疲劳裂纹扩展试验。裂纹长度和宏观裂纹闭合使用卸载弹性柔量法测量。在所有疲劳试验条件下，裂纹尾流周围均观察到晶粒互锁，这意味着该材料的疲劳裂纹扩展与循环载荷下晶粒互锁的逐渐退化有关。等幅载荷下的疲劳裂纹扩展速率da/dn不仅受最大应力强度因子K_（max）D_（max）D_（2）的控制，而且受应力幅的影响，其中K_（max）D_（max）D_（2）是循环疲劳裂纹扩展的最重要因素。超载和高水平载荷偏移导致低水平载荷下疲劳裂纹扩展加速和裂纹闭合点降低。这种下降被认为是由于更多的撞击或药柱联锁的摩擦磨损，裂纹闭合可以定性地解释加速行为。

项目成果

菅田淳: "Fatigue Crack Growth Behavior in Silicon Nitride under Constant and Variable Amplitude Load Sequences"Materials Science Research International.

Jun Suda：“恒幅和变幅载荷序列下氮化硅的疲劳裂纹扩展行为”材料科学研究国际。

菅田淳: "Si_3N_4-BN複合焼結セラミックスの疲労き裂進展挙動に及ぼす荷重変動の影響"日本材料学会第24回疲労シンポジウム. 250-253 (1998)

Jun Suda：“载荷波动对Si_3N_4-BN复合烧结陶瓷疲劳裂纹扩展行为的影响”，日本材料学会第24届疲劳研讨会250-253（1998）。

菅田 淳: "Si_3N_4-BN複合焼結セラミックスにおける疲労き裂進展特性" 日本機械学会第74期関西支部講演会. (1999)

Jun Suda：“Si_3N_4-BN复合烧结陶瓷中的疲劳裂纹扩展特性”日本机械工程学会第74届关西分会讲座（1999年）。

菅田淳: "窒化けい素の一定および変動荷重下における疲労き裂進展挙動の微視的観察"日本材料学会 第49期学術講演会. (2000)

Jun Suda：“恒定和可变载荷下氮化硅疲劳裂纹扩展行为的显微观察”，日本材料学会第49届学术会议（2000年）。

Atsushi Sugeta, Masahiro Jono and Yoshihiko Uematsu: "Microscopic Observation of Fatigue Crack Growth Behavior in SiィイD23ィエD2NィイD24ィエD2 Ceramics under Constant and Variable Amplitude Load Sequences"JSMS 49ィイD1thィエD1 Annual Meeting. (2000)

Atsushi Sugeta、Masahiro Jono 和 Yoshihiko Uematsu：“恒幅和变幅加载序列下 SiD23D2ND24D2 陶瓷中疲劳裂纹扩展行为的微观观察”JSMS 49D1D1 年会（2000 年）