Fracture toughness of ceramics at elevated temperature and metallurgical factors for controlling the toughness

陶瓷高温断裂韧性及控制韧性的冶金因素

• 批准号: 60550048
• 负责人: MUTOH Yoshiharu
• 金额: $ 1.22万
• 依托单位: Technological University of Nagaoka
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60550048/
• 关键词: Ceramics; Fracture toughness; Elevated temperature strength; Sintering method; Testing method for fracture toughness; Fatigue precrack; 窒化けい素

Three-point bend tests of four kinds of silicon nitrides with the same chemical composition, which were produced by different sintering methods and under different sintering conditions, were carried out at elevated temperature. Effects of sintering method and density on fracture strength were investigated. Effects of sintering method and density on fracture toughness evaluated by using the indentation method and fractographic method were also investigated. A new method for evaluating fracture toughness of ceramics, where fatigue precrack was introduced at elevated temperature, was developed. Main results are summarized as follows.(1) Fracture strengths were decreased with reducing density. The Weibull modulus m seemed to depend upon the sintering mehtod. (2) Fracture toughness values and also the Weibull modulus m were decreased with reducing density. (3) Fatigue precrack was successfully introduced into a notched bend specimen of silicon nitride at 1200゜C. The fatigue precrack specimen satisfied the conditions for fracture toughness specimen required by the standard of ASTM E399. (4) Fracture toughness values obtained by fatigue precracked specimens were almost equal to those obtained by using the indentation method. Fracture toughness malues up to the temperature of 1000゜C were almost the same as those at room temperature.

对不同烧结方法、不同烧结条件下制备的四种相同化学成分的氮化硅材料进行了高温三点弯曲试验，研究了烧结方法和密度对断裂强度的影响。还研究了采用压痕法和断口法评价陶瓷断裂韧性的烧结方法和密度的影响，提出了一种在高温下引入疲劳预裂纹的陶瓷断裂韧性评价方法。主要结果总结如下：（1）断裂强度随密度降低而降低，威布尔模量m似乎取决于烧结方法。（2）断裂韧性值和威布尔模量m随密度降低而降低。 (3)在1200°C的氮化硅缺口弯曲试件中成功引入了疲劳预裂纹，疲劳预裂纹满足了标准要求的断裂韧性试件的条件。 (4)疲劳预裂试样获得的断裂韧性值与使用压痕法获得的断裂韧性值几乎相同，直至1000°C的温度几乎与室温下的断裂韧性值相同。温度。

项目成果

Y. Mutoh, K. Tanaka, and T. Niwa: "Fracture Toughness Test of Fatigue Precracked Silicon Nitride" Preprint of 35th Annual Meeting of the Society of Materials Science,Japan. 35. 319-321 (1986)

Y. Mutoh、K. Tanaka 和 T. Niwa：“疲劳预裂氮化硅的断裂韧性测试”日本材料学会第 35 届年会预印本。

武藤睦治,田中紘一,丹羽敏男: 日本機械学会論文集.

Mutsuji Muto、Koichi Tanaka、Toshio Niwa：日本机械工程师学会会议录。

武藤睦治,田中紘一,丹羽敏男: 第29回材料研究連合講演会前刷集. 121-122 (1985)

Mutoji Muto、Koichi Tanaka、Toshio Niwa：第 29 届材料研究联盟讲座预印本集 121-122 (1985)。

Y. Mutoh, K. Tanaka, and T. Niwa: "Effects of Sintering Method and Density on Mechanical Properties and Fracture Toughness of Silicon Nitride at Elevated Temperature" Journ. of JSME.

Y. Mutoh、K. Tanaka 和 T. Niwa：“烧结方法和密度对高温下氮化硅机械性能和断裂韧性的影响”杂志。

武藤睦治,田中紘一,丹羽敏男: 材料学会第35期学術講演会前刷. 319-321 (1986)

Muto Muto、Koichi Tanaka、Toshio Niwa：日本材料学会第 35 届学术会议预印本 319-321（1986）。