1991 Fiscal Year Final Research Report Summary
Superplastic Forming of Ceramics
| Project/Area Number |
01850154
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
金属加工(含鋳造)
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| Research Institution | The university of Tokyo |
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Principal Investigator |
SAKUMA Taketo Professor, University of Tokyo, 工学部, 教授 (50005500)
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| Co-Investigator(Kenkyū-buntansha) |
KIKUCHI Norihumi Mitsubishi Material Co. Ltd., 中央研究所, 室長
YOSHIZAWA Yu-ichi Research Assistant, University of Tokyo, 工学部, 助手 (00200973)
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| Project Period (FY) |
1989 – 1991
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| Keywords | alumina / zirconia / Al_2O_3-ZrO_2 / superplasticity / grain growth |
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| Research Abstract |
The results obtained are summarized as follows,
(1) The high-temperature deformability in TZP is improved by an addition of small amount of grain boundary glass phase. The addition of 5 wt% lithium-aluminosilicate glass results in about 200ﾟC decrease of superplastically deformed temperature. TZP containing this glass deforms superplastically at 1100ﾟC.
(2) The marked grain growth and cavitation during high-temperature deformation retards the tensile ductility of high-purity Al_2O_3. The MgO addition effectively suppresses the grain growth of Al_2O_3 and consequently improves the ductility. The maximum elongation obtained is 70% at 1400ﾟC.
(3) The high-temperature flow stress in Al_2O_3-ZrO_2 depends markedly on zirconia content. A sharp peak value is obtained in Al_2O_3-2wt%ZrO_2. The composition dependence of flow stress can qualitatively be explained by assuming that the grain boundary sliding is much difficult along Al_2O_3/ZrO_2 boundary than other boundaries.
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