The typical experimental conditions inside a transmission electron microscope (TEM), such as ultra-high vacuum, high-energy electron irradiation, and surface effects of ultrathin TEM specimens, can be the origin of unexpected microstructural changes compared with that of bulk material during in situ thermal-annealing experiments. In this paper, we report on the microstructural changes of a Fe–15%Si alloy during in situ TEM annealing, where, in its bulk form, it exhibits an ordering transformation from D03 to B2 at 650 °C. Using a heating-pot type double tilt holder with a proportional–integral–differential control system, we observed the precipitation of α-Fe both at the sample surface and inside the sample. Surface precipitates formed via surface diffusion are markedly large, several tens of nm, whereas precipitates inside the specimen, which are surrounded by Fe-poor regions, reach a maximum size of 20 nm. This unexpected microstructural evolution could be attributed to vacancies on Si sites, which are induced due to high-energy electron irradiation before heating, as well as enhanced thermal diffusion of Fe atoms.
REFERENCES
1.
C.
Hayzelden
, J. L.
Batstone
, and R. C.
Cammarata
, “In situ transmission electron microscopy studies of silicide-mediated crystallization of amorphous silicon
,” Appl. Phys. Lett.
60
, 225
–227
(1992
). 2.
T. J.
Konno
and R.
Sinclair
, “Crystallization of silicon in aluminium/amorphous-silicon multilayers
,” Philos. Mag. B
66
, 749
–765
(1992
). 3.
J.
Won
, A.
Kovács
, M.
Naito
, M.
Ishimaru
, and Y.
Hirotsu
, “Formation processes of iron silicide nanoparticles studied by ex situ and in situ transmission electron microscopy
,” J. Appl. Phys.
102
, 103512
(2007
). 4.
S.
Ii
, T.
Hirota
, K.
Fujimoto
, Y.
Sugimoto
, N.
Takata
, K.
Ikeda
, H.
Nakashima
, and H.
Nakashima
, “Direct evidence of polycrystalline silicon thin films formation during aluminum induced crystallization by in-situ heating TEM observation
,” Mater. Trans.
49
, 723
–727
(2008
). 5.
T.
Kamino
and H.
Saka
, “A newly developed high resolution hot stage and its application to materials characterization
,” Microsc. Microanal. Microstruct.
4
, 127
–135
(1993
). 6.
L. F.
Allard
, W. C.
Bigelow
, M.
Jose-Yacaman
, D. P.
Nackashi
, J.
Damiano
, and S. E.
Mick
, “A new MEMS-based system for ultra-high-resolution imaging at elevated temperatures
,” Microsc. Res. Tech.
72
, 208
–215
(2009
). 7.
Y.
Shimada
, K.
Yoshida
, K.
Inoue
, T.
Shiraishi
, T.
Kiguchi
, Y.
Nagai
, and T. J.
Konno
, “Evaluation of spatial and temporal resolution on in situ annealing aberration-corrected transmission electron microscopy with proportional-integral-differential controller
,” Microscopy
68
, 271
–278
(2019
). 8.
K.
Yoshida
, M.
Shimodaira
, T.
Toyama
, Y.
Shimizu
, K.
Inoue
, T.
Yoshiie
, K. J.
Milan
, R.
Gerard
, and Y.
Nagai
, “Weak-beam scanning transmission electron microscopy for quantitative dislocation density measurement in steels
,” Microscopy
66
, 120
–130
(2017
). 9.
Y.
Du
, K.
Yoshida
, Y.
Shimada
, T.
Toyama
, K.
Inoue
, K.
Arakawa
, T.
Suzudo
, K. J.
Milan
, R.
Gerard
, S.
Ohnuki
, and Y.
Nagai
, “In-situ WB-STEM observation of dislocation loop behavior in reactor pressure vessel steel during post-irradiation annealing
,” Materially
12
, 100778
(2020
). 10.
M.
Haider
, S.
Uhlemann
, E.
Schwan
, H.
Rose
, B.
Kabius
, and K.
Urban
, “Electron microscopy image enhanced
,” Nature
392
, 768
–769
(1998
). 11.
K.
Sato
, T. J.
Konno
, and Y.
Hirotsu
, “Atomic structure imaging of L10-type FePd nanoparticles by spherical aberration corrected high-resolution transmission electron microscopy
,” J. Appl. Phys.
105
, 034308
(2009
). 12.
M. D.
Rossell
, R.
Erni
, M.
Asta
, V.
Radmilovic
, and U.
Dahmen
, “Atomic-resolution imaging of lithium in Al3Li precipitates
,” Phys. Rev. B
80
, 024110
(2009
). 13.
D. S.
Su
, T.
Jacob
, T. W.
Hansen
, D.
Wang
, R.
Schlogl
, B.
Freitag
, and S.
Kujawa
, “Surface chemistry of Ag particles: Identification of oxide species by aberration-corrected TEM and by DFT calculations
,” Angew. Chem.
120
, 5083
–5086
(2008
). 14.
M.
Tikhonchev
, V.
Svetukhin
, A.
Kadochkin
, and E.
Gaganidze
, “MD simulation of atomic displacement cascades in Fe–10 at.%Cr binary alloy
,” J. Nucl. Mater.
395
, 50
–57
(2009
). 15.
P. D.
Edmondson
, W. J.
Weber
, F.
Namavar
, and Y.
Zhang
, “Determination of the displacement energies of O, Si and Zr under electron beam irradiation
,” J. Nucl. Mater.
422
, 86
–91
(2012
). 16.
17.
I.
Ohnuma
, S.
Abe
, S.
Shimenouchi
, T.
Omori
, R.
Kainuma
, and K.
Ishida
, “Experimental and thermodynamic studies of the Fe–Si binary system
,” ISIJ Int.
52
, 540
–548
(2012
). 18.
J.
Zheng
, S.
Ostrach
, and Y.
Kamotani
, Transport Phenomena in Heat and Mass Transfer (Elsevier Science, 1992), pp. 675–692.19.
K.
Nii
and K.
Yoshihara
, “The effect of oxygen potential on the surface self-diffusion coefficient of α-Fe
,” Trans. Jpn. Inst. Met.
20
, 523
–532
(1979
). 20.
H.
Mehrer
, M.
Eggersmann
, A.
Gude
, M.
Salamon
, and B.
Sepiol
, “Diffusion in intermetallic phases of the Fe–Al and Fe–Si systems
,” Mater. Sci. Eng. A
239–240
, 889
–898
(1997
). 21.
K.
Raviprasad
and K.
Chattopadhyay
, “The influence of critical points and structure and microstructural evolution in iron rich Fe-Si alloys
,” Acta Metall. Mater.
41
, 609
–624
(1993
). 22.
S.
Matsumura
, Y.
Tanaka
, Y.
Koga
, and K.
Oki
, “Concurrent ordering and phase separation in the vicinity of the metastable critical point of order–disorder transition in Fe–Si alloys
,” Mater. Sci. Eng. A
312
, 284
–292
(2001
). 23.
Y.
Ustinovshikov
and I.
Sapegina
, “Morphology of ordering Fe-Si alloys
,” J. Mater. Sci.
39
, 1007
–1016
(2004
). 24.
U.
Starke
, J.
Schardt
, W.
Weiss
, W.
Meier
, C.
Polop
, P. L.
Andres
, and K.
Heinz
, “Structural and compositional reversible phase transitions on low-index Fe3Si surfaces
,” Europhys. Lett.
56
, 822
–828
(2001
). 25.
H.
Busse
, J.
Kandler
, B.
Eltester
, K.
Wandelt
, G. R.
Castro
, J. J.
Hinarejos
, P.
Segovia
, J.
Chrost
, E. G.
Michel
, and R.
Miranda
, “Metastable iron silicide phase stabilized by surface segregation on Fe3Si(100)
,” Surf. Sci.
381
, 133
–141
(1997
). © 2022 Author(s). Published under an exclusive license by AIP Publishing.
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