Kinetic Measurement of the Martensitic Transformation in Y-TZP Samll Particles

Y-TZP小颗粒马氏体相变的动力学测量

• 批准号: 09650718
• 负责人: HAYAKAWA Motozo
• 金额: $ 2.11万
• 依托单位: Tottori University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650718/
• 关键词: tetragonal zirconia polycrystals; yttria doped; spherical particles; agglomcration in oil; martensitic transformation; isothermal martensite; kinetics measurement; micro-dilatometer

Kinetics of the martensitic transformation of yttria doped zirconia was studied on small spherical specimens of 500 mum size prepared by the agglomeration method in oil. The main results obtained are as follows :1. Small spherical specimens allowed to study the transformation kinetics by rapid cooling and heating treatments. Rapid quenching resulted in a highly metastable tetragonal phase at room temperature for the zirconia containing small amount of yttria which normally transform during the usual cooling rate for a bulk specimen. The fact suggested that the martensitic transformation involves a thermally activated process.2. The metastable t-phase underwent isothermal transformation when held at an intermediate temperature. The kinetics was described by a C-curve in the TTT diagram with an upper limit at 450ﾟC and a nose at 350ﾟC.3. The metastable t-phase undergoes a burst transformation during subzero-cooling. The Ms temperature was located at-1 18+-6ﾟC.4. From the above observation, it was verified that the metastable t-phase undergoes both isothermal and athermal transformations depending on the heat treatment. Such phenomenon cannot be explained by the existing theories of the nucleation of martensite.

在油中用团聚法制备的500μm尺寸的小球形样品上研究了氧化钇掺杂氧化锆的马氏体相变动力学。取得的主要结果如下： 1．小球形样品可以通过快速冷却和加热处理来研究转变动力学。快速淬火导致含有少量氧化钇的氧化锆在室温下产生高度亚稳态的四方相，氧化钇通常在块状样品的通常冷却速率期间发生转变。这一事实表明马氏体转变涉及一个热激活过程。 2．当保持在中间温度时，亚稳态t相经历等温转变。动力学由 TTT 图中的 C 曲线描述，上限为 450°C，鼻子为 350°C.3。亚稳态 t 相在零下冷却期间经历突发转变。 Ms温度位于-1 18+-6°C.4。从以上观察，证实亚稳t相根据热处理同时经历等温和非热转变。这种现象无法用现有的马氏体成核理论来解释。

项目成果

M.Hayakawa et al.: "Lizuiol Phase Sintering of Y-TZP with aio and Y_2Cu_2O_5 Dapants" Mater.Sci.Forum. 304-306. 465-470 (1999)

M.Hayakawa 等人：“Y-TZP 与 aio 和 Y_2Cu_2O_5 Dapants 的 Lizuiol 相烧结”Mater.Sci.Forum。

T.Onda et al.: "Effect of Divolent Elements on the Grain Growth of TZP" Mater.Sci.Forum. 304-306. 471-475 (1999)

T.Onda 等人：“二价元素对 TZP 晶粒生长的影响”Mater.Sci.Forum。

T.Onda et al.: "Effect of Divalent Elements On the Grain Growth of TZP" Mater.Sci.Forum. 304-306. 471-475 (1999)

T.Onda 等人：“二价元素对 TZP 晶粒生长的影响”Mater.Sci.Forum。

M.Hayakawa, H.Miyauchi, A.Ikegami, and M.Nishida: ""Elastic Constants of Zirconia Single Crystals Determined by X-ray Measurements for Polycrystals"" Materials Trans.JIM. 39,2. 268-274 (1998)

M.Hayakawa、H.Miyauchi、A.Ikegami 和 M.Nishida：“通过多晶 X 射线测量确定氧化锆单晶的弹性常数”Materials Trans.JIM。

T.Onda, K.Okazaki, M.Hayakawa, H.Yamauchi and H.Suematsu: ""Effect of Divalent Elements on the Grain Growth of a Zirconia-12mol% Ceria Alloy"" Proc.IMSP'97, Mie University Press. 59-64 (1998)

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