1986 Fiscal Year Final Research Report Summary
APPLICATION OF STRENGTHENING TECHNICS FOR STEELS ON THE STRENGT OF CERAMICS
| Project/Area Number |
59460173
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
金属材料(含表面処理・腐食防食)
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
SUTO Hajime TOHOKU UNIVERSITY, 工学部, 教授 (10005176)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIKWA Noboru TOHOKU UNIVERSITY, 工学部, 助手 (70166924)
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| Project Period (FY) |
1984 – 1986
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| Keywords | Ceramics / Ferroelastic state / Paraelastic state / Partially stabilized zirconia / Phase diagram / Spinodal decomposition |
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| Research Abstract |
<ZrO_2> HAS POLYMORPHS OF CUBIC,TETRAGONAL AND MONOCLINIC PHASES FROM HIGH TO LOW TEMPERATURES WHEN <Y_2O_3> IS ADDED, TETRAGONAL PHASE CAN BE OBTAINED AT ROOM TEMPERATURE,AND SHOWS VERY HIGH TOUGHNESS AS THE RESULTS OF STRESS INDUCED TRANSFORMATION FROM TETRAGONAL TO MONOCLINIC ACCOMPANYING WITH VOLUME EXPANSION. THIS CERAMICS IS CALLED PARTIALLY STABILIZED ZIRCONIA, "PSZ". SIMILAR TOUGHNING MECHANISM CAN BE FOUND IN STEELS. IN THIS STUDY, THE TOUGHENING TECHNIQUES DEVELOPED IN THE FIELD OF STEELS ARE APPLIED FOR THE TOUGHENING OF CERAMICS,ESPECIALLY PSZ. AT FIRST, ZIRCONIA-YTTRIA PHASE DIAGRAM WAS INVESTIGATED BY MEANS OF DILATOMETRY AND EPMA. AND NEW DIAGRAM WAS PROPOSED. THE SHAPE OF SOLUBILITY LINES IN THIS DIAGRAM IS VERY CHARACTERISTIC. THE REASON WAS CONSIDERED AND IT WAS CONCLUDED THAT THE TETRAGONAL-CUBIC TRANSFORMATION WAS A PARA-FERROELASTIC SECOND ORDER TRANSITION AND TETRAGONAL PHASE COULD BE TRANSFERED CONTINUOUSLY TO CUBIC PHASE WITH INCREASING EASING <Y_2O_3> CONTENTS. FROM THESE NEW ASPECTS ON THE PHASEDIAGRAM, THE FORMATION MECHANISMS OF VARIOUS MICROSTRUCTURES INCLUDING DOMAIN,MARTENSITIC STRUCTURES, ANTI-PHASE BOUNDATIES IN QUENCHED SPECIMENS AND SPINODAL DECOMPOSITION IN ANNEALED SPECIMENS WERE DISCUSSED,AND THEN THE TOUGHENING PROCESS WERE TRIED ON PSZ.
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Research Products
(2 results)
