1988 Fiscal Year Final Research Report Summary
Development of High Temperature Creep Testing Machine for Ceramics and the Assessment of High Temperature Strength and Deformation of Engineering Ceramics
| Project/Area Number |
62850020
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
機械材料工学
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| Research Institution | Tokyo Institute of Technology (1990)
Faculty of Science and Engineering (1987-1988) |
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Principal Investigator |
TANAKA Tsuneshichi Faculty of Science and Engineering, Ritsumeikan University, Professor, 理工学部, 教授 (90066613)
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| Co-Investigator(Kenkyū-buntansha) |
FUJII Tsutomu Technical Department, Tokyo Koki Seizosho, Chief of R & D, 技術開発課, 課長
OKABE Nagatoshi Heavy Apparatus Engineering Laboratory, Toshiba Corporation, Chief Researcher, 重電技術研究所, 主査
NAKAYAMA Hideaki Faculty of Junior College of Automobile Industry, Osaka Industrial University, P, 短期大学部, 教授 (90097999)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Ceramics / High temperature creep / Silicon carbide / Silicon nitride / Creep curve / Steady state creep rate / クリープラプチャ強度 |
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| Research Abstract |
The purpose of the study was to develop a high temperature creep testing machine of engineering ceramics in order to establish a proper method of high temperature strength assessment of fine ceramics. The study was performed in two fiscal years from 1987 to 1988, at the Depart-ment of Mechanical Engineering of the Faculty of Science and Engineering, Ritsumeikan University.
In developing the creep testing machine, the test temperature was set in the range from 1000 to 1350゜C, and an electric furnace with Kanthal-super heating wire was successfully used to maintain the temperature within the variation of + 0.5% for a testing period as long as 30 days. The load-ing system was in its principle the same as those of the ordinary creep testing macines for metals, but the gripping device of the specimen was carefully designed to avoid a load misalignment and to eliminate a fracture of specimen at gripped parts. Silicon carbide was used for this device to resist the high testing temperature. The
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same material was used for detect-ing rods of the creep strain of a parallel part of the specimen, and a high sensitive lever with an electlic sensor was used to monitor the strain. The variation of the creep strain was stored in a personal computer and recorded automatically.
Creep tests were carried out using silicon carbide and silicon nitride cylindrical specimens with the maximum testing temperature of 1350゜C. Even at this temperature, silicon carbide showed no creep strain and a rupture occurred macroscopically in a brittle manner after sustaining an applied load for a cirtain time period. On the other hand, silicon nitride showed a creep strain at 1200 and 1250゜C and its creep curve has a clear tendency comprising three regions as in the case of steels and other metal alloys. An important finding is that the rupture time is determined primarily by the steady state creep rate, and the creep rate is related to the applied stress at each temperature.
Studies were also made on the compressive strength and bending fatigue strength of silicon nitride at room temperature, as related studies. Less
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