照射誘起結晶化 (高速電子照射)


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照射誘起結晶化 (高速電子照射)

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MeV electron irradiation can introduce irradiation defects in an amorphous phase, resulting in the devitrification (crystallization) of an amorphous phase (amorphous-to-crystal transition) in some metallic glasses, while it can bring about the collapse of the crystalline structure (SSA). The enhancement and stimulation of the thermal crystallization by electron irradiation had been found at 1970s and 1980s [1, 2]. The irradiation induce crystallization at significantly lower temperature than the thermal crystallization temperature (room temperature) was found in Fe88Zr9B3 amorphous alloy [3], and the irradiation induced crystallization was not stimulated by the temperature increase but by the irradiation enhanced diffusion. The irradiation induced crystallization of an amorphous phase in metallic glass with wide supercooled liquid region was also found in Zr-based metallic glasses [4-6], As shown in the review papers [7, 8], a lot of melt-spun metallic glasses were crystallized by electron irradiation at an acceleration voltage of 2.0 MV at room temperature. Irradiation-induced crystallization under MeV electron irradiation with a high dose rate (over 10^23 m-2s-1) is commonly observed in metallic materials.

REFERENCES
[1] J. L. Brimhall, J. Mater. Sci. 19 (1984) 1818-1826.
[2] M. Doi, M. Yoshida, M. Nonoyama, T. Imura, T. Masumoto, Y. Yashiro, Mater. Sci. Eng. 23 (1976) 169-172.
[3] T. Nagase, Y. Umakoshi, N. Sumida, Mater. Sci. Eng. A 323 (2002) 218-225., http://dx.doi.org/10.1016/S0921-5093(01)01351-X
[4] T. Nagase, Y. Umakoshi, Sci. Tech. Adv. Mater., 3, 119 (2002)., http://dx.doi.org/10.1016/S1468-6996(02)00013-X
[5] T. Nagase, Y. Umakoshi, J. Appl. Phys., 93, 912-918 (2003)., http://dx.doi.org/10.1063/1.1529073
[6] T. Nagase, Y. Umakoshi, Mater. Trans., 45, 13-23 (2004)., http://www.jim.or.jp/journal/e/45/01/13.html
[7] T. Nagase: Advanced materials design by irradiation of high energy particles, in: Progress in Advanced Structural and Functional Materials Design, Ed., T. Kakeshita, Springer, 2013. pp. 137-153. ISBN 978-4-431-54063-2, http://www.springer.com/materials/structural+materials/book/978-4-431-54063-2
[8] T. Nagase, T. Sanda, A. Nino, W. Qin, H. Yasuda, H. Mori, Y. Umakoshi, J.A. Szpunar, J. of Non-Cryst. Solids, 358, 502-518 (2012)., http://dx.doi.org/10.1016/j.jnoncrysol.2011.11.010




データベース, 照射誘起結晶化 (高速電子照射)




アモルファス相の照射損傷 - 自由体積 と アンチ自由体積

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Figure 1
Schematic illustration of defects in single-component metal system produced by single-atom displacement. (a) frenkel pair in a crystal, (b) free volume like and anti-free volume like defects in an amorphous phase [1-5].


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Figure 2
Schematic illustration of defects in multi-component amorphous alloy produced by single-atom displacement [5].


Under MeV electron irradiation, only single or, at most, double atom displacements of constituent elements can occur by the knock-on mechanism. Figure 1 shows a schematic illustration of the atomic defects in single-element crystalline and amorphous phases introduced by the electron knock-on effect. In the crystalline phases (a), not only a vacancy but also an interstitial is introduced under the irradiation, where the existence of an interstitial can be ignored in materials without irradiation. A vacancy type of a free volume like defect and an interstitial type of anti free volume like defect [1-4] are introduced in an amorphous phase under the irradiation (b). Figure 2 shows the schematic illustration of the defects in multi-component amorphous alloy. One can notice that many type defects can be considered in an amorphous phase. The concept of two-type defects is important for clarifying the mechanis of the irradiation induced crystallization of an amorphous phase.

REFERENCES
[1] T. Egami, K. Maeda, D. Srolovitz, V. Vitek.: J. Phys. 41, C8-272-C8-275 (1980)
[2] Y. Petrusenko, A. Bakai, V. Borysenko, A. Astakhov, D. Barankov, Intermetallics 17, 246-248 (2009).
[3] T. Nagase, T. Hosokawa, Y. Umakoshi: Intermetallics 18, 767-772 (2010), http://dx.doi.org/10.1016/j.intermet.2009.12.003
[4] T. Nagase, Y. Umakoshi: Intermetallics 18 1803-1808 (2010), http://dx.doi.org/10.1016/j.intermet.2010.02.044
[5] T. Nagase, Advanced materials design by irradiation of high energy particles, in: Progress in Advanced Structural and Functional Materials Design, Ed., T. Kakeshita, Springer, 2013. pp. 137-153., ISBN 978-4-431-54063-2, http://www.springer.com/materials/structural+materials/book/978-4-431-54063-2




ピンポイントナノ結晶化

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Figure 1
Pinpointe nanocrystallization of an amorphous phase in Fe-9Zr-3B alloy [1,2].

The ordered array nano-crystallization area whose diameter is about 1 mm can be realized by MeV electron irradiation indcued crystallization tecnique by use of High Voltage Electron Microscope [1,2]

REFERENCES
[1] T. Nagase, A. Nino and Y. Umakoshi: Mater. Sci. Forum., 561-565, 1402-1406 (2007). http://dx.doi.org/10.4028/www.scientific.net/MSF.561-565.1403
[2] T. Nagase: Materia Japan, 49, 323-324 (2010). (in Japanese), http://dx.doi.org/10.2320/materia.49.323


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Last-modified: 2020-12-20 (日) 10:14:00