https://scholars.lib.ntu.edu.tw/handle/123456789/424914
標題: | Effects of dopant segregation on lattice-diffusional creep of nanocrystalline ceramics | 作者: | Hsueh C.H. Becher P.F. CHUN-HWAY HSUEH |
公開日期: | 2005 | 卷: | 71 | 期: | 1 | 來源出版物: | Physical Review B - Condensed Matter and Materials Physics | 摘要: | The segregation of dopants whose electric charge is different from that of the parent ions and the formation of a space-charge layer induce a local electric field in the grain-boundary region. Depending upon the valence and local electrostatic potential, the charge carriers controlling diffusional creep can be either accumulated or depleted in this space-charge layer, and the creep rate is enhanced or diminished accordingly. A model was recently developed to examine the effects of a segregation-induced local electric field on the lattice-diffusional creep of nanocrystalline ceramics for spherical grains. However, in order to obtain closed-form solutions, the grain size was assumed to be much greater than the width of the space-charge layer in the existing analysis. This assumption can become inappropriate for nanocrystalline materials as the grain size is reduced; thus, a numerical method is used in the present study to resolve the existing equations without that assumption. Using yttria tetragonal zirconia as an example, the difference between the existing approximate closed-form solutions and the present numerical results is shown to be significant when the grain size is less than 50 nm. ? 2005 The American Physical Society. |
URI: | https://scholars.lib.ntu.edu.tw/handle/123456789/424914 | ISSN: | 10980121 | DOI: | 10.1103/PhysRevB.71.014115 |
顯示於: | 材料科學與工程學系 |
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