In situ Observation of Crack Growth in Structural Ceramics and Microstructural Characterization

结构陶瓷裂纹扩展的原位观察和微观结构表征

• 批准号: 09650728
• 负责人: SUGANO Mikio
• 金额: $ 2.3万
• 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: 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-09650728/
• 关键词: In situ observation; Crack growth mechanism; Si; SiC ceramics; SiィイD23ィエD2NィイD24ィエD2; Bridging; Fractal characteristics; Microstructure; Microstructural charcterization; SiC焼結体; SiCセラミックス; き裂進展挙動; フラクタル特性; 微構造

To clarify the micromechanisms of fracture and crack growth in engineering ceramics, microstructures in the process zone and zone wake of cracks were examined by transmission electron microscope (TEM) for the Si/SiC (TPCC) and PLS SiィイD23ィエD2NィイD24ィエD2 (TSN-03) ceramics which were subjected to fracture toughness measurement tests. The tests were carried out by a short bar method for the PLS SiィイD23ィエD2NィイD24ィエD2 ceramics and by a three-point bend test for the Si/SiC ones with chevron notched bean specimens. The three-point bend test was conducted at an elevated temperature (1673K) as well as at room temperature. As to the PLS SiィイD23ィエD2NィイD24ィエD2 (TSN-03) ceramics, it was found that microcracking appeared to be independent of dislocation structures. Some of grain boundary microcracks were connected with grain bridging phenomena. Main cracks were often observed to grow on the (0001) basal plane of an elongated β-SiィイD23ィエD2NィイD24ィエD2 grain. As to the Si/SiC ceramics, on the other hand, typical microstructures of the surfaces fractured at room temperature were characterized by stacking faults in the SiC grains and by dislocation structures in silicon phases. At elevated temperatures, crack temperatures, crack growth in transgranular modes would be related to the evolution of dense stacking faults. In addition, cyclic fatigue tests were also carried out on ZrOィイD22ィエD2 thin plate specimen to study fatigue crack growth behavior under cyclic stressing in plane bending from the microstructural points of view. The results were discussed in connection with martensitic transformation caused in the process zone wake of fatigue crack.

为了阐明工程陶瓷断裂和裂纹扩展的微观机理，利用透射电子显微镜（TEM）对Si/SiC（TPCC）和PLS Si/SiC D23陶瓷D2 N陶瓷D24陶瓷D2（TSN-03）进行了断裂韧性测试，并对断裂过程区和裂纹区尾流区的微观结构进行了观察。采用短棒法对PLS Si/SiC D23/D2 N/D24/D2陶瓷进行了试验，采用三点弯曲试验对Si/SiC陶瓷进行了试验。在高温（1673 K）和室温下进行了三点弯曲测试。对于PLS Si_（23）Si_（24）Si_部分晶界微裂纹与晶界架桥现象有关。在β-Si单晶D23单晶D2 N单晶D24单晶D2晶粒的（0001）基面上常观察到主裂纹的生长。至于Si/SiC陶瓷，在另一方面，在室温下断裂的表面的典型显微结构的特征在于在SiC晶粒中的堆垛层错和在硅相中的位错结构。在高温下，裂纹温度，裂纹扩展在穿晶模式将与密集的层错的演变。此外，还对ZrO_（12）D_22合金薄板试样进行了循环疲劳试验，从微观组织角度研究了平面弯曲循环应力下的疲劳裂纹扩展行为。并结合疲劳裂纹尾流过程区马氏体相变对结果进行了讨论。

项目成果

H.Kisuki st al.: "Fatigue Behavior of Type 316L Stainless Steel Coated with Plasma-Sprayed Alumina in Corrosive Environment"Proc. of 15th Int. Thermal Spray Conf., Nice. 1115-1120 (1998)

H.Kisuki 等人：“腐蚀环境中等离子喷涂氧化铝涂层 316L 型不锈钢的疲劳行为”Proc。