| Autor: |
Masao Ono, Yusuke Iguchi, Rabaya Bagum, Kimio Fujii, Satoru Okayasu, Fumitaka Esaka, Tsutomu Mashimo, Glaucio H. Paulino, Marek-Jerzy Pindera, Robert H. Dodds, Fernando A. Rochinha, Eshan Dave, Linfeng Chen |
| Rok vydání: |
2008 |
| Předmět: |
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| Zdroj: |
AIP Conference Proceedings. |
| ISSN: |
0094-243X |
| DOI: |
10.1063/1.2896825 |
| Popis: |
We had previously realized atomic‐scale graded structures in several miscible alloys by an ultracentrifuge experiment. In this study, we performed an ultracentrifuge experiment on a MgCd order‐disorder alloy at disordered state of solid solution. The experimental conditions were as follows: maximum acceleration: 0.61×106 g level, temperature: 400 °C, composition: Mg:Cd = 50:50 at%, time duration: 60 h. The ultracentrifuge was stopped after cooling the sample from 400 °C (disordered state) to 100 °C (ordered state). According to the composition analysis by EPMA, the graded structure was formed in the centrifuged sample, in which Cd content continuously increased in the direction of gravitational field. We also investigated the crystal state of the centrifuged sample by XRD. It was found that there was changing of unit cell volume with composition. This result showed that the graded structure was continuous in atomic‐scale and it was formed by sedimentation of atoms. Based on the simulation of sedimentation process, the diffusion coefficient for sedimentation in this alloy was estimated to be almost the same as usual diffusion. We also found that the existence of an unusual crystal state might also be considered due to the disorder‐order transformation under the strong gravitational field.We had previously realized atomic‐scale graded structures in several miscible alloys by an ultracentrifuge experiment. In this study, we performed an ultracentrifuge experiment on a MgCd order‐disorder alloy at disordered state of solid solution. The experimental conditions were as follows: maximum acceleration: 0.61×106 g level, temperature: 400 °C, composition: Mg:Cd = 50:50 at%, time duration: 60 h. The ultracentrifuge was stopped after cooling the sample from 400 °C (disordered state) to 100 °C (ordered state). According to the composition analysis by EPMA, the graded structure was formed in the centrifuged sample, in which Cd content continuously increased in the direction of gravitational field. We also investigated the crystal state of the centrifuged sample by XRD. It was found that there was changing of unit cell volume with composition. This result showed that the graded structure was continuous in atomic‐scale and it was formed by sedimentation of atoms. Based on the simulation of sedimentation... |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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