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1996 Fiscal Year Final Research Report Summary

Study on the High Temperature Strength of Ceramics and Ceramics Coating Materials Using Laser Speckle Strain/Displacement Gage

Research Project

Project/Area Number 06452151
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Materials/Mechanics of materials
Research InstitutionOsaka University

Principal Investigator

OGURA Keiji  Osaka University, Faculty of Engineering Science, Prof., 基礎工学部, 教授 (70029007)

Co-Investigator(Kenkyū-buntansha) AMANO Jun  Matsue National College of Technology, Assoc.Prof., 助教授 (50222683)
NISHIKAWA Izuru  Osaka University, Faculty of Engineering Science, Assoc.Prof., 基礎工学部, 助教授 (90189267)
Project Period (FY) 1994 – 1996
KeywordsCeramics / Ceramics Coating / Fatigue strength / High temperature / Static / Cyclic Fatigue / Laser Speckle / Crack Closure / Bridging
Research Abstract

In this study, fatigue crack growth tests for alumina ceramics and silicon nitride ceramics were performed at both room and elevated temperature. The crack opening displacement was also measured during the tests. Then the crack growth characteristics of ceramics were discussed using these experimental data. The results concerned with the crack growth tests are as follows.
1.The crack growth rate was found to decrease gradually with a further crack growth, and after some crack extension a crack stopped growing temporary for both ceramics materials.
2.It was found from the relationship between COD and stress intensity factor, K,that a crack opening level, Kop, increased with increasing the number of cycles. A little bit wide hysteresis was also observed in these curves. These hysteresis were thought to correspond with the effect of particle bridging on the crack opening behavior. Furthermore, the compliance of sample varied discontinuously with increasing the number of cycles.
3.Both the cr … More ack arrest mentioned the above and the variation on the compliance related to the existence of the particle bridging effect near the crack tip. The stress intensity factor at crack tip was reduced by subtracting the friction stress due to this bridging effect.
Next, fatigue tests for ceramics coating materials were conducted at both room and elevated temperature. The results for coating materials are as follows.
1.While the blasted sample at room temperature has a higher fatigue limit than the annealed sample at the same temperature, the alumina coated sample has a lower fatigue limit that the blasted sample.
2.Though the ceramics coated sample shows the elastic deformation at an early stage of fatigue life under a higher applied stress level, the plastic deformation increased with increasing the number of cycles at a middle stage of fatigue life. This behavior corresponded with the cyclic softening behavior of substrate. At a final stage of fatigue life the surface strain of the sample varied discontinuously. This means that the region with no strain due to the delamination among a coat material and a substrate appeared.
3.Under a lower applied stress level, the sample was under an elastic state at an early stage, and gradually showed the plastic deformation behavior. At a final stage of fatigue life, however, the plastic strain range of sample decreased with increasing the number of cycles. This means that a single main crack can only propagate under this condition. Less

  • Research Products

    (12 results)

All Other

All Publications (12 results)

  • [Publications] 西川 出,小倉敬二,山上正文,桑山健太郎: "レーザスペックルゲージSSDGによるひずみ・き裂開口変位計測" 材料. 43-493. 1290-1296 (1994)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 小倉敬二,西川 出: "破壊力学研究におけるレーザ応用変位・ひずみ計測" 材料. 44-502. 891-898 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Keiji OGURA, Izuru NISHIKAWA, Masafumi YAMAGAMI, Hirotaka TANABE: "Laser Speckle Strain Measurements and Crack Initiation in Type304 Stainless Steel under Thermal Striping" Fatigue '97. 1955-1960 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Keiji OGURA, Izuru NISHIKAWA: "Laser Speckle Strain/Displacement Gage and Its Application to Fracture Prpblems of Ceramics and Ceramics Coating" Proceeding of Asian Pacific Conference for Fracture and Strength '96. 1290-1296 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 小倉敬二,西川 出,坂本博夫: "レーザスペックルによるセラミックスの高温下微小CODの直接計測" 日本機械学会講演論文集. No. 95-10. 348-349 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 小倉敬二,西川 出,門阪宗樹,田中盛彦: "窒化ケイ素およびアルミナセラミックスのCOD計測と疲労き裂進展挙動" 日本機械学会講演論文集. No. 974-1. 59-60 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Izuru NISHIKAWA,Keiji OGURA,Masafumi YAMAGAMI and Kentaro KUWAYAMA: "New Development of Laser Speckle Strain/Displacement Gage for the Measurement of Fracture Mechanics Parameters (in Japanese)" Journal of Materials Science, Japan. 43-493. 1290-1296 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Keiji OGURA and Izuru NISHIKAWA: "Laser Strain/Displacements for Fracture Mechanics Research (in Japanese)" Journal of Materials Science, Japan. 44-502. 891-898 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Keiji OGURA,Izuru NISHIKAWA,Masafumi YAMAGAMI and Hirotaka TANABE: "Laser Speckle Strain Measurements and Crack Initiation in Type304 Stainless Steel under Thermal Striping" Fatigue '96. 1955-1960 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Keiji OGURA and Izuru NISHIKAWA: "Laser Speckle Strain/Displacement Gage and Its Application to Fracture Problems of Ceramics and Ceramics Coating" Proceedings of Asian Pacific Conference for Fracture and Strength '96. 749-754 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Keiji OGURA,Izuru NISHIKAWA and Hiroo SAKAMOTO: "Direct Measurement of Small Crack Opening Displacement of Ceramics at High Temperature Using Laser Speckle Strain/Displacement Gage (in Japanese)" Preprint of Japan Society of Mechanical Engineering. No.95-10. 348-349 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Keiji OGURA,Izuru NISHIKAWA,Muneki KADOSAKA and Morihiko TANAKA: "Crack Opening Displacement Measurement of Silicon Nitride and Alumina Ceramics and Observation of Fatigue Crack Growth Behavior (in Japanese)" Preprint of Japan Society of Mechanical Engineering. No.974-1. 59-60 (1997)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-03-09  

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