Crack Growth Mechanism in Structural Ceramics and Microstructural Analysis

结构陶瓷中的裂纹扩展机制及微观结构分析

• 批准号: 07650778
• 负责人: SUGANO Mikio
• 金额: $ 1.34万
• 依托单位: Yamagata University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07650778/
• 关键词: Silicon Nitride; Zirconia; Crack growth mechanism; Three point bending strength; Fracture toughness; Strength at elevated temperature; Cyclic fatigue; Microstructural analysis; 破壊靱性; 高温強度異方性; 微構造

Microstructures of the process zone and the process zone wake which are developed around growing cracks were studied by scanning and transmission electron microscopy. The results obtained are as follows.1) The anisotropy of bending strength (sigma_b) and fracture toughness (K_<IC>) in hot-pressed (HP) Si_3N_4 ceramics has been studied at room temperature to 1573 K.Specimens were cut out parallel (HP-LS,HP-LT) and perpendicular (HP-SL,HP-ST) to the hot-pressing direction. The chevron notched beam method was employed for the K_<IC> measurement and the three-point bending test for obtaining the sigma_b. The anisotropy was found in the K_<IC> at the testing temperature up to 1073 K,but hardly at 1473 K.However, it reappeared at 1573 K remarkably. In the sigma_b this was discernible up to 1473K,although differences between the HP-LT and the HP-ST specimens decreased with increasing temperature and diminished at 1573 K.The results obtained were discussed in connection with the orientation of elongated beta-phase grains, comparing with those of pressureless sintered (PLS) specimens.2) The effects of temperature on bending strength and fracture toughness of zirconia ceramics have been studied in connection with microstructural changes in the process zone wake of a crack. Three point bending and fracture toughness measurement tests have been carried out at room temperature, 873 and 1273K.Microstructures in the vicinity of cracks and on fracture surfaces were examined by SEM,TEM and X-ray diffraction techniques. At the higher temperatures the three-point bending strength and the K_<IC> values decreased to about one third of that at room temperature. The stress induced phase transformation from tetragonal structure to monoclinic one has occurred more greatly at room temperature than at the higher temperatures. In the case of cyclically fatigued specimens, microstructures developed around fatigue cracks have also been studied by SEM and TEM techniques.

通过扫描和透射电子显微镜研究了过程区域的微观结构和围绕生长裂纹而开发的过程区唤醒。 The results obtained are as follows.1) The anisotropy of bending strength (sigma_b) and fracture toughness (K_<IC>) in hot-pressed (HP) Si_3N_4 ceramics has been studied at room temperature to 1573 K.Specimens were cut out parallel (HP-LS,HP-LT) and perpendicular (HP-SL,HP-ST) to the hot-pressing direction.用于K_ <ic>测量和获得SIGMA_B的三分弯曲测试，采用了雪vron孔方法。在测试温度高达1073 K时在K_ <ic>中发现了各向异性，但在1473 K时几乎不在1473 k中。在sigma_b中，这是可辨别到1473K的，尽管HP-LT和HP-ST标本之间的差异随着温度的升高而降低，并在1573 K时降低。在1573 K时降低。与延长的β-相晶粒的方向相关，讨论了所获得的结果，并与无压的（pls and pressirted and profcement and prance and profcement and prance and versimens and vection.2）效应效果。已经研究了与裂纹的过程区唤醒的微观结构变化有关的研究。在室温（873和1273K）上进行了三点弯曲和断裂韧性测量测试。通过SEM，TEM和X射线衍射技术检查了裂纹附近和裂缝表面上的Microstructures。在较高的温度下，在室温下，三分弯曲强度和K_ <ic>值降至大约三分之一。在室温下，应力引起的相变从四方结构到单斜结构的变化比在较高的温度下发生的更大。在周期性疲劳的样品的情况下，SEM和TEM技术还研究了围绕疲劳裂纹的微观结构。

项目成果

菅野幹男他: "Si_3N_4焼結体の高温強度特性" 日本機械学会・平成7年度材料力学部門講演会講演論文集. Vol.B. 331-332 (1995)

Mikio Kanno 等：“Si_3N_4 烧结体的高温强度特性”日本机械工程学会论文集 1995 年材料力学分部讲座第 331-332 卷（1995 年）。

Mikio Sugano, Tadaaki Satake and Rikiya Ishikawa: "The Effects of Atmosphere on Fatigue Crack Growth Behavior in Zirconia" Proc.of the 1996 Annual Meeting of JSPE Tohoku Chapter. 69-71 (1996)

Mikio Sugano、Tadaaki Satake 和 Rikiya Ishikawa：“大气对氧化锆疲劳裂纹扩展行为的影响”，JSPE 东北分会 1996 年年会会议记录。

菅野幹男他: "ジルコニア薄板材の疲労き裂進展挙動に及ぼす雰囲気の影響" 精密工学会東北支部学術講演会講演論文集. 69-70 (1996)

Mikio Kanno等人：“气氛对氧化锆薄板材料的疲劳裂纹扩展行为的影响”日本精密工程学会东北分会学术会议记录69-70（1996）。

菅野幹男他: "ジルコニア焼結体のき裂進展挙動と微構造" セラミックスの破壊力学に関するシンポジウム講演論文集. 96-52. 68-71 (1996)

Mikio Kanno 等人：“氧化锆烧结体的裂纹扩展行为和微观结构”陶瓷断裂力学研讨会论文集 96-52 (1996)。

Mikio Sugano, Rikiya Ishikawa, Makoto Ebina and Tadaaki Satake: "Fatigue Crack Growth Behavior of Zirconia Thin Plates under Alternate Plane Bending" Proc.of the 1996 Annual Meeting of JSME/MMID. Vol.B,96-10. 413-414 (1995)

Mikio Sugano、Rikiya Ishikawa、Makoto Ebina 和 Tadaaki Satake：“交替平面弯曲下氧化锆薄板的疲劳裂纹扩展行为”JSME/MMID 1996 年年会会议记录。