Radiation induced softening of crystals
Under irradiation of crystals, atomic vibrations of the lattice that are large enough in amplitude so that the linear approximation and therefore the conventional phonon description of the lattice is not enough. At the same time, these vibrations are localized and can travel long distances in a crys...
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Dubinko, V.I. Borysenko, V.N. Kushnir, V.A. Khodak, I.V. Mytrochenko, V.V. Gamov, V.O. 2023-12-05T11:07:04Z 2023-12-05T11:07:04Z 2021 Radiation induced softening of crystals / V.I. Dubinko, V.N. Borysenko, V.A. Kushnir, I.V. Khodak, V.V. Mytrochenko, V.O. Gamov // Problems of Atomic Science and Technology. — 2021. — № 6. — С. 22-25. — Бібліогр.: 9 назв. — англ. 1562-6016 PACS: 61.80.x, 63.20.Pw, 87.15.Aa DOI: https://doi.org/10.46813/2021-136-022 https://nasplib.isofts.kiev.ua/handle/123456789/195462 Under irradiation of crystals, atomic vibrations of the lattice that are large enough in amplitude so that the linear approximation and therefore the conventional phonon description of the lattice is not enough. At the same time, these vibrations are localized and can travel long distances in a crystal lattice [1,2]. In metals and other crystals, they are called discrete breathers (DBs), which are the secondary products of irradiation damage, the primary one being the creations of defects that involve atom displacements to produce point and extended defects, which results in radiation induced hardening (RIH). A part of the remaining energy transforms in DBs before decaying into phonons. Thus, while a material is being irradiated in operational conditions, as in a reactor, a considerable amount of DBs with energies of the order of one eV is produced, which helps dislocations to unpin from pinning centers, producing Radiation Induced Softening (RIS), which opposes RIH [3,4]. This effect is investigated under (in-situ) impulse and steady-state electron irradiation. При опроміненні кристалів виникають атомні коливання кристалічної решітки, які є достатньо великими за амплітудою, так що лінійного наближення і, отже, звичайного фононного опису решітки недостатньо. У той же час, ці вібрації локалізовані і можуть проїжджати великі відстані [1,2]. У металах та інших кристалах вони називаються дискретними бризерами (ДБ) і є вторинними продуктами пошкодження опроміненням, основними з яких є точкові та розширені дефекти, що призводять до радіаційно-індукованого зміцнення. Частина енергії, що залишилася, трансформується в ДБ, перш ніж розпадатися на фонони. Таким чином, поки матеріал опромінюється в робочих умовах, як у реакторі, існує значна кількість ДБ з енергіями порядку одного електронвольта, що допомагає дислокаціям відкріпитися від центрів закріплення, приводячи до радіаційно-індукованої пластифікації (РІП) кристалів, що протистоїть радіаційно-індукованому зміцненню [3,4]. Цей ефект досліджується при (in-situ) імпульсному та стаціонарному електронному опроміненні. При облучении кристаллов возникают атомные колебания кристаллической решетки, которые являются достаточно большими по амплитуде, так что линейного приближения и, следовательно, обычного фононного описания решетки недостаточно. В то же время, эти колебания локализованы и могут распространяться на большие расстояния [1,2]. В металлах и других кристаллах они называются дискретными бризерами (ДБ) и являются вторичными продуктами радиационного облучения, основными из которых являются точечные и протяженные дефекты, приводящие к радиационно-индуцированному упрочнению. Часть энергии трансформируется в ДБ, прежде чем распадаться на фононы. Таким образом, пока материал облучается в рабочих условиях как в реакторе, возникает значительное количество ДБ с энергиями порядка одного электронвольта, что помогает дислокациям открепляться от центров закрепления и приводит к радиационно-индуцированной пластификации (РИП) кристаллов, противостоящей радиационно-индуцированному упрочнению [3,4]. Этот эффект исследуется при (in-situ) импульсном и стационарном электронном облучении. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Interaction of relativistic particles with crystals and matter Radiation induced softening of crystals Радіаційно-індукована пластифікація кристалів Радиационно-индуцированная пластификация кристаллов Article published earlier |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| title |
Radiation induced softening of crystals |
| spellingShingle |
Radiation induced softening of crystals Dubinko, V.I. Borysenko, V.N. Kushnir, V.A. Khodak, I.V. Mytrochenko, V.V. Gamov, V.O. Interaction of relativistic particles with crystals and matter |
| title_short |
Radiation induced softening of crystals |
| title_full |
Radiation induced softening of crystals |
| title_fullStr |
Radiation induced softening of crystals |
| title_full_unstemmed |
Radiation induced softening of crystals |
| title_sort |
radiation induced softening of crystals |
| author |
Dubinko, V.I. Borysenko, V.N. Kushnir, V.A. Khodak, I.V. Mytrochenko, V.V. Gamov, V.O. |
| author_facet |
Dubinko, V.I. Borysenko, V.N. Kushnir, V.A. Khodak, I.V. Mytrochenko, V.V. Gamov, V.O. |
| topic |
Interaction of relativistic particles with crystals and matter |
| topic_facet |
Interaction of relativistic particles with crystals and matter |
| publishDate |
2021 |
| language |
English |
| container_title |
Вопросы атомной науки и техники |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| format |
Article |
| title_alt |
Радіаційно-індукована пластифікація кристалів Радиационно-индуцированная пластификация кристаллов |
| description |
Under irradiation of crystals, atomic vibrations of the lattice that are large enough in amplitude so that the linear approximation and therefore the conventional phonon description of the lattice is not enough. At the same time, these vibrations are localized and can travel long distances in a crystal lattice [1,2]. In metals and other crystals, they are called discrete breathers (DBs), which are the secondary products of irradiation damage, the primary one being the creations of defects that involve atom displacements to produce point and extended defects, which results in radiation induced hardening (RIH). A part of the remaining energy transforms in DBs before decaying into phonons. Thus, while a material is being irradiated in operational conditions, as in a reactor, a considerable amount of DBs with energies of the order of one eV is produced, which helps dislocations to unpin from pinning centers, producing Radiation Induced Softening (RIS), which opposes RIH [3,4]. This effect is investigated under (in-situ) impulse and steady-state electron irradiation.
При опроміненні кристалів виникають атомні коливання кристалічної решітки, які є достатньо великими за амплітудою, так що лінійного наближення і, отже, звичайного фононного опису решітки недостатньо. У той же час, ці вібрації локалізовані і можуть проїжджати великі відстані [1,2]. У металах та інших кристалах вони називаються дискретними бризерами (ДБ) і є вторинними продуктами пошкодження опроміненням, основними з яких є точкові та розширені дефекти, що призводять до радіаційно-індукованого зміцнення. Частина енергії, що залишилася, трансформується в ДБ, перш ніж розпадатися на фонони. Таким чином, поки матеріал опромінюється в робочих умовах, як у реакторі, існує значна кількість ДБ з енергіями порядку одного електронвольта, що допомагає дислокаціям відкріпитися від центрів закріплення, приводячи до радіаційно-індукованої пластифікації (РІП) кристалів, що протистоїть радіаційно-індукованому зміцненню [3,4]. Цей ефект досліджується при (in-situ) імпульсному та стаціонарному електронному опроміненні.
При облучении кристаллов возникают атомные колебания кристаллической решетки, которые являются достаточно большими по амплитуде, так что линейного приближения и, следовательно, обычного фононного описания решетки недостаточно. В то же время, эти колебания локализованы и могут распространяться на большие расстояния [1,2]. В металлах и других кристаллах они называются дискретными бризерами (ДБ) и являются вторичными продуктами радиационного облучения, основными из которых являются точечные и протяженные дефекты, приводящие к радиационно-индуцированному упрочнению. Часть энергии трансформируется в ДБ, прежде чем распадаться на фононы. Таким образом, пока материал облучается в рабочих условиях как в реакторе, возникает значительное количество ДБ с энергиями порядка одного электронвольта, что помогает дислокациям открепляться от центров закрепления и приводит к радиационно-индуцированной пластификации (РИП) кристаллов, противостоящей радиационно-индуцированному упрочнению [3,4]. Этот эффект исследуется при (in-situ) импульсном и стационарном электронном облучении.
|
| issn |
1562-6016 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/195462 |
| citation_txt |
Radiation induced softening of crystals / V.I. Dubinko, V.N. Borysenko, V.A. Kushnir, I.V. Khodak, V.V. Mytrochenko, V.O. Gamov // Problems of Atomic Science and Technology. — 2021. — № 6. — С. 22-25. — Бібліогр.: 9 назв. — англ. |
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ISSN 1562-6016. ВАНТ. 2021. № 6(136) 22
https://doi.org/10.46813/2021-136-022
RADIATION INDUCED SOFTENING OF CRYSTALS
V.I. Dubinko, V.N. Borysenko, V.A. Kushnir, I.V. Khodak, V.V. Mytrochenko, V.O. Gamov
National Science Center “Kharkov Institute of Physics and Technology”, Kharkiv, Ukraine
Under irradiation of crystals, atomic vibrations of the lattice that are large enough in amplitude so that the linear
approximation and therefore the conventional phonon description of the lattice is not enough. At the same time, the-
se vibrations are localized and can travel long distances in a crystal lattice [1, 2]. In metals and other crystals, they
are called discrete breathers (DBs), which are the secondary products of irradiation damage, the primary one being
the creations of defects that involve atom displacements to produce point and extended defects, which results in ra-
diation induced hardening (RIH). A part of the remaining energy transforms in DBs before decaying into phonons.
Thus, while a material is being irradiated in operational conditions, as in a reactor, a considerable amount of DBs
with energies of the order of one eV is produced, which helps dislocations to unpin from pinning centers, producing
Radiation Induced Softening (RIS), which opposes RIH [3, 4]. This effect is investigated under (in-situ) impulse and
steady-state electron irradiation.
PACS: 61.80.x, 63.20.Pw, 87.15.Aa
INTRODUCTION
One of the main factors limiting the service lifespan
of the nuclear reactors is the radiation-induced
embrittlement caused by the radiation-induced harden-
ing of Fe based steels used as structural materials for
pressure vessels etc. Defects formed by irradiation in
the bulk act as additional pinning centers, resulting in
the well-known effect of radiation-induced hardening
(RIH). On the other hand, there is experimental evi-
dence of radiation-induced softening (RIS) under elec-
tron, gamma or neutron irradiation at low and medium
temperatures. The RIS has been discovered in the early
1960s [5] and investigated extensively thereafter (see
e.g. [6]). Single crystals of Zn, Sn, In and Pb have been
irradiated at liquid nitrogen temperature (78 K) with
electron flux density ranging from 10
17
to 10
18
m
-2
s
-1
and energies below and above the threshold displace-
ment energies, the latter being 0.7 MeV (Zn), 0.8 MeV
(Sn, In) and 1.2 MeV (Pb). At such low temperatures
plastic strain occurs via dislocation glide, the rate of
which is limited by thermally activated unpinning of
dislocations from local obstacles. Subsequently, new
experimental evidence was obtained on the radiation-
induced increase of plasticity of polycrystalline Cu
(99.5%), Al (99.5%) and Al-3Mg under in situ electron
irradiation at the room temperature [3, 4]. The electron
energy of 0.5 MeV used in these experiments was high-
er than the threshold displacement energy in Al (0.15
MeV) and about that for Cu. In all cases, irradiation
resulted in the decrease of yield stress and increase of
the elongation to fracture, i.e. a metal under irradiation
instantly became less hard and more ductile as com-
pared to the state prior and after irradiation. These re-
sults demonstrated that mechanical properties of materi-
als under reactor conditions could be different from
those tested 'out of pile' in the surveillance program.
The present experiments were designed so that to al-
low comparison between over-threshold irradiation of
Al and polycrystalline Fe (and commercial steel 20),
which is a base metal of the reactor structural materials
in order to make the results more closely related to the
real in-reactor environment. For this purpose the beam
energy for the Fe irradiation was increased from 0.5 to
0.8 MeV, which is sufficient to produce displacement
damage at a rate of 10
-9
dpa/s (where dpa denotes ‘dis-
placements per atom’) which is comparable to the dose
rates in nuclear reactor environment.
The main result obtained here is that the yield stress
of Fe is decreased by irradiation, as well as the ultimate
resistance to fracture, the latter being in a marked con-
trast to Al and Cu cases, which points out at the radia-
tion-induced localization of plastic strain in Fe. So the
Fe-based metal under irradiation became less hard and
more brittle at the same time. These results mean that
dynamics of dislocations has been changed due to their
interaction with radiation-induced excitations of the
lattice, the nature of which needs to be determined. The
underlying mechanisms of RIS are still a subject of de-
bate [7]. One of the possible mechanisms is based on
special kind of lattice vibrations, namely, discrete
breathers (DBs), also known as intrinsic localized
modes, can be generated either by thermal fluctuations
or by external triggering such as irradiation. The ampli-
tude of atomic oscillations in the DBs greatly exceeds
that of harmonic oscillations (phonons). Due to the crys-
tal anharmonicity, the frequency of atomic oscillations
increases or decreases with raising the amplitude so that
the DB frequency lies outside the phonon frequency
band, which explains the weak coupling of DBs with
phonons and, consequently, their stability against decay
even at elevated temperatures. DBs have been success-
fully observed experimentally in various physical sys-
tems [8] and materials ranging from metals to diatomic
insulators [9]. This field of research is comparatively
new, lying at the conjunction of nonlinear physics with
material science. The main hypothesis of the present
paper is that DBs present a viable catalyzing mechanism
for the dislocation unpinning from obstacles under irra-
diation that triggers DB generation.
The paper is organized as follows. In the next sec-
tion, experimental setup is described. In section 3, re-
sults of discrete electron irradiation of bcc Fe (99.5%)
are presented in comparison with analogous results for
fcc Al reported in refs. [3, 4]. In section 4, results of
continuous electron irradiation of bcc Fe (99.5%) are
presented in comparison with analogous results for steel
20.
ISSN 1562-6016. ВАНТ. 2021. № 6(136) 23
1. EXPERIMENTAL SETUP
The present technical approach combines electron ir-
radiation (compact electron linear accelerator,
E < 1 MeV) with in-situ mechanical testing at the instal-
lation, which measures a yield stress drops during irra-
diation pulses and the stress-strain deformation curve
under continuous irradiation. Experimental procedure
and installation is described in details in ref. [4]. Elec-
tron beam of the energy ranging from 0.5 to 0.8 MeV and
the beam density ranging from 2.4 to 3.6×10
13
cm
-2
s
-1
was directed at a metal specimen subjected to tensile
load. The time diagram of the electron beam pulses (the
fine pulse structure) is shown in Fig. 1. Micro-pulses of
duration, τm = 4×10
-11
s, were shot periodically with an
interval of 3×10
-10
s during the bunch time,
τbunch= (2…4)×10
-6
s. The bunch frequency, 1/Т0, was
25 Hz. An overall irradiation time ranged from 10 to
3000 s in different irradiation regimes.
Fig. 1. Time dependence of the electron beam
pulses [4]
Specimens had a form of a parallelepiped with
broader ends for fixing and the following dimensions of
the irradiated part: 0.52(±0.01)×4×30 mm
3
. They were
cut of technically pure iron (0.048%С) annealed in
vacuum in two regimes: (1) Т = 900С for 1 hour result-
ing to a mean grain size of 7 microns; (2) Т = 1150С
for 2.5 hours resulting to a mean grain size of 150 mi-
crons. At the experimental temperature (slightly above
RT), Fe matrix has a bcc structure with impurities pre-
cipitated in the form of various obstacles for dislocation
glide, which increases the initial yield stress of material
(prior to irradiation) to ~ 200 MPa as compared to
~ 50…100 MPa for technologically pure Fe. The micro-
structure of the 'steel 20' is much more complex, but
principally, it consists of ferritic bcc iron grains (with
some Carbon in solution) and a certain fraction of per-
lite grains, which doubles its strength as compared to
the strength of technically pure iron.
The specimens were subjected to uniaxial tensile
load in the deformation installation, which was regis-
tered in the coordinates – load, P, vs. time, t, with delay
ranging from 1 to 0.3 s and sensitivity of 0.1%. The load
is related to the external stress, , as = P(1+ε)/S,
where S is the specimen cross-section and is the de-
formation calculated by = vdt/l, where vd is the veloci-
ty of the deformation rod, l is the specimen length. The
load measurement accuracy was about (0.1…1) N. The
velocity of the deformation rod was 0.5 µms
-1
, which
corresponded to the deformation rate of 2×10
-4
s
-1
,
i.e. typically used in the standard tensile tests. The sur-
face temperature of the specimens during testing was
measured independently with infrared pyrometer and
thermocouples attached to the specimen outside the ir-
radiated area.
Effect of the irradiation on plastic deformation of
Fe and Al was studied at room temperature applying the
discrete and continuous regimes of irradiation. In the
first case, specimens were irradiated under external load
within the short time intervals tirr followed by the inter-
vals without irradiation. In the second case, the speci-
mens were irradiated under external load continuously
up to the fracture point.
2. DISCRETE IRRADIATION
OF Al AND Fe AT ROOM TEMPERATURE
In the following tests, the specimens were exposed
to discrete irradiation pulses with tirr ~ 60 s, during
which the yield stress drops sharply by the value, δσφ,
and then it increases at a lower rate than that without
irradiation, as can be seen in Fig. 2.
Fig. 2. Yield stress drops during deformation (a)
of Fe specimens (Tann=1150С) under electron beam
with Е = 0.8 МeV, φ = 3.6×10
13
сm
-2
s
-1
and (b) Al specimens under electron beam
with Е = 0.5 МeV, φ = 5×10
13
сm
-2
s
-1
[4]
Let us define a deformation strengthening rate as θ =
dσ/dε. When the electron beam is switched on (φ ≠ 0),
the yield stress drops sharply by the value, δσφ, and sub-
sequently a prolonged deformation stage occurs, at
which the deformation strengthening rate θφ, is always
lower than that without irradiation θ0, and it can be even
negative for some time. When the electron beam is
switched off (φ = 0), the yield stress jumps up sharply
by the value, δσφ, (equal to the initial stress drop) and
subsequently grows with time at a rate θ0. As a result,
ISSN 1562-6016. ВАНТ. 2021. № 6(136) 24
the net external stress decreases by the value Δσφ, which
indicates that the metal microstructure changes during
irradiation, the material becomes more soft under irradi-
ation pulse as compared to the unirradiated state, and
the effect persist for some time after the pulse.
The initial stress drop/jump at the moment of the
beam switching on/off, δσφ, is shown in Fig. 3 for Fe
specimens annealed at Tann=900ºС, which are harder
initially than those annealed at 1150ºС. It can be seen
that δσφ increases linearly with increasing deformation
and the beam density.
Fig. 3. (a) The initial stress drop/jump at the moment
of the beam switching on/off as a function of defor-
mation for Fe specimens (Tann=900ºС) under electron
beam with Е = 0.8 МeV, φ = 2.4×10
13
сm
-2
s
-1
(line 1);
3.6×10
13
сm
-2
s
-1
(line 2); Fe specimens annealed
at 1150ºС at φ = 3.6×10
13
сm
-2
s
-1
(line 3, color online).
Yield stress evolution of Fe specimens (Tann=1150ºС)
during one irradiation cycle is shown in (b) while the
corresponding time evolution of specimen temperature
is shown in (c)
The value δσφ characterizes an instant (and reversi-
ble) response of the metal to irradiation, which can not
be explained by the radiation or strain induced trans-
formation of microstructure that takes much longer
times than the times of the stress drops/jumps by δσφ.
We may conclude here that during irradiation pulses
material becomes softer by two mechanisms. One is
reversible (δσφ > 0) and the other one is irreversible
(θφ < θ0), which results in material softening both during
and shortly after the irradiation pulse.
3. CONTINUOUS IRRADIATION REGIME
During continuous irradiation under increasing
strain, the specimen temperature increases gradually as
shown in Fig. 4. The deformation curves measured
without and under irradiation show that irradiation re-
sults in a decrease of the yield stress as well as of the
ultimate elongation before fracture of all specimens
under investigation. It means that the plasticity limit
(strain to fracture) is decreased under irradiation by
~20%, in a remarkable contrast to Al and Cu samples
for which it was increased by ~25…30% [3, 4]. The
result demonstrated in Fig. 4,a was reproduced in four
specimens, every time showing significant reduction of
the strain to fracture. Clearly, the capacity of the materi-
al to sustain plastic deformation is strongly affected by
the irradiation.
Fig. 4. (a) Deformation curves without (open symbols)
and under (filled symbols) irradiation for Fe specimens
(red – Tann= 900ºС; blue – Tann= 1150ºС).
Electron energy Е = 0.8 МeV,
φ = 2.4×10
13
сm
-2
s
-1
. (b) The same for steel 20 at
Е = 0.5 МeV, φ = 2.4×10
13
сm
-2
s
-1
ISSN 1562-6016. ВАНТ. 2021. № 6(136) 25
CONCLUSIONS
The present experiments were designed to allow
comparison between sub-threshold and over-threshold
electron irradiation of bcc and fcc metals, which did not
show any significant difference.
The radiation-induced softening (RIS) effect was
demonstrated for technically pure Fe as well as for pre-
viously studied Al and Cu. It is represented by (i) re-
versible decrease of the yield stress by ~ 1% at the mo-
ment of switching on electron beam and (ii) by irre-
versible decrease of the yield stress by ~ 10% under
continuous irradiation up to the material fracture.
The RIS effect on the elongation to fracture of Fe ap-
pears to be opposite to that for Al and Cu, where electron
irradiation increases elongation to fracture by ~25…30%.
In contrast to that, the elongation to fracture of Fe speci-
mens was decreased by irradiation by ~20%, which is
significant reduction as compared to the result obtained
by the standard test. This discrepancy may have im-
portant implications regarding the programs forecasting
the service lifetime of Fe-based structural steels.
We may conclude that the radiation-induced for-
mation of DBs may change mechanical properties of
materials under reactor conditions as compared to the
surveillance specimens in out-reactor tests after equiva-
lent irradiation dose. The RIS phenomenon needs fur-
ther investigations due to its importance for the ade-
quate qualification of the mechanical performance of
the materials under reactor operating conditions.
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Article received 04.10.2021
РАДИАЦИОННО-ИНДУЦИРОВАННАЯ ПЛАСТИФИКАЦИЯ КРИСТАЛЛОВ
В.И. Дубинко, В.Н. Борисенко, В.А. Кушнир, И.В. Ходак, В.В. Митроченко, В.О. Гамов
При облучении кристаллов возникают атомные колебания кристаллической решетки, которые являются
достаточно большими по амплитуде, так что линейного приближения и, следовательно, обычного фононного
описания решетки недостаточно. В то же время, эти колебания локализованы и могут распространяться на
большие расстояния [1, 2]. В металлах и других кристаллах они называются дискретными бризерами (ДБ) и
являются вторичными продуктами радиационного облучения, основными из которых являются точечные и
протяженные дефекты, приводящие к радиационно-индуцированному упрочнению. Часть энергии транс-
формируется в ДБ, прежде чем распадаться на фононы. Таким образом, пока материал облучается в рабочих
условиях как в реакторе, возникает значительное количество ДБ с энергиями порядка одного электронволь-
та, что помогает дислокациям открепляться от центров закрепления и приводит к радиационно-
индуцированной пластификации (РИП) кристаллов, противостоящей радиационно-индуцированному уп-
рочнению [3, 4]. Этот эффект исследуется при (in-situ) импульсном и стационарном электронном облучении.
РАДІАЦІЙНО-ІНДУКОВАНА ПЛАСТИФІКАЦІЯ КРИСТАЛІВ
В.І. Дубінко, В.М. Борисенко, В.А. Кушнір, I.В. Ходак, В.В. Мітроченко, В.О. Гамов
При опроміненні кристалів виникають атомні коливання кристалічної решітки, які є достатньо великими
за амплітудою, так що лінійного наближення і, отже, звичайного фононного опису решітки недостатньо. У
той же час, ці вібрації локалізовані і можуть проїжджати великі відстані [1, 2]. У металах та інших кристалах
вони називаються дискретними бризерами (ДБ) і є вторинними продуктами пошкодження опроміненням,
основними з яких є точкові та розширені дефекти, що призводять до радіаційно-індукованого зміцнення.
Частина енергії, що залишилася, трансформується в ДБ, перш ніж розпадатися на фонони. Таким чином,
поки матеріал опромінюється в робочих умовах, як у реакторі, існує значна кількість ДБ з енергіями поряд-
ку одного електронвольта, що допомагає дислокаціям відкріпитися від центрів закріплення, приводячи до
радіаційно-індукованої пластифікації (РІП) кристалів, що протистоїть радіаційно-індукованому зміцненню
[3, 4]. Цей ефект досліджується при (in-situ) імпульсному та стаціонарному електронному опроміненні.
http://link.springer.com/journal/11451
https://www.sciencedirect.com/science/article/pii/S1359645410000352
https://www.sciencedirect.com/science/article/pii/S1359645410000352
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