Creep and Creep Fracture of Oxide Ceramics

氧化物陶瓷的蠕变和蠕变断裂

• 批准号: 63550581
• 负责人: OKAMOTO Yasunori
• 金额: $ 1.22万
• 依托单位: Kyoto Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1988
• 资助国家: 日本
• 起止时间: 1988 至 1989
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63550581/
• 关键词: Ceramics; Creep; Fracture; Deformation; Zirconia; Glass ceramics; Mullite; Diffusion; クリープ; クリープ破壊; キャビテーション; 応力腐食割れ; 粒界クラック

The effects of microstructures (grain size, second phase, etc) on high temperature deformation such as creep and creep fracture were studied for some oxide ceramics; magnesias with and without an intergranular glass phase, a fine-grained, yttria stabilized tetragonal zircoenia exhibiting superplasticity, a beta-spodumene glass ceramic and fine-grained, single phase mullite (3Al_2O_3・2SiO_2). Glass phases in the magnesia and the glass ceramic enhanced the creep strain rates by pressure solution. However, they were the origins of cavitation, resulting in microcracking at grain boundaries. Modern ceramics often have very fine microstructures without apparent glassy phases, thus show sometimes high ductility (superplasticity in some cases) at high temperatures, leading the application to plastic forming. On the other hand, these ceramics show limited resistance to deformation in high-temperature structural application. The mullite was shown to have high creep resistance in spite of its fine grain size (1.5 mum) and to have high strength in creep fracture. The increase in grain size of the mullite led to cavitation at grain boundaries and thus lowered the creep fracture stress, as observed in Y-TZP. The criterion for initiation of cavitation was difficult to determine, which is the next step of this study.

研究了氧化陶瓷的显微组织（晶粒尺寸、第二相等）对蠕变和蠕变断裂等高温变形的影响；镁：含晶间玻璃相和不含晶间玻璃相、细晶、钇稳定的具有超塑性的四方氧化锆、β -锂辉石玻璃陶瓷和细晶、单相莫来石（3Al_2O_3·2SiO_2）。氧化镁和玻璃陶瓷中的玻璃相通过压力溶解提高了蠕变应变速率。然而，它们是空化的根源，导致晶界处的微裂纹。现代陶瓷通常具有非常精细的微观结构，没有明显的玻璃相，因此在高温下有时表现出高延展性（在某些情况下是超塑性），导致应用于塑性成型。另一方面，这些陶瓷在高温结构应用中表现出有限的抗变形能力。莫来石晶粒细（1.5 μ m），但具有较高的抗蠕变性能，并具有较高的蠕变断裂强度。在Y-TZP中观察到，莫来石晶粒尺寸的增大导致晶界空化，从而降低了蠕变断裂应力。空化起始的标准难以确定，这是本研究的下一步。

项目成果

Y.Okamoto;K.Hayashi;T.Nishikawa: Proceedings of the Symposium on the Reliability of Structural Ceramics(Advanced Materials Science and Engineering).

Y.Okamoto；K.Hayashi；T.Nishikawa：结构陶瓷可靠性研讨会论文集（先进材料科学与工程）。

Y. Okamoto: "Creep Deformation Mechanisms in Oxides and Deformation of Spinel Ferrites" Rheology of Solids and of the Earth, ed. S. Karato and M. Toriumi, Oxford University Press, pp.83-104(1989).

Y. Okamoto：“氧化物中的蠕变变形机制和尖晶石铁氧体的变形”固体和地球流变学，编辑。

Y.Okamoto: "Creep Deformation Mechanisma in Oxides and Deformation of Spinel Ferrites" Rheology of Solids and of the Earth. 83-104 (1989)

Y.Okamoto：“氧化物中的蠕变变形机制和尖晶石铁氧体的变形”固体和地球的流变学。

S. Saito, at al. (Ed.): Encyclopedia of Advanced Material Applications. Sangyo Chosakai, 1239 29-32 (1990)

S. Saito，等。

斉藤進六(編): "先端材料応用事典" 産業調査会, (1990)

Shinroku Saito（编辑）：“先进材料应用百科全书”工业研究协会，（1990）