Nano-mechanisms of connection in the solid phase of tungsten and tantalum in the manufacture of a neutron source target
Nano-mechanisms of solid-phase bonding of tungsten and tantalum, which are implemented in the manufacture of a neutron source target for the research nuclear facility (RNF) of NSC KIPT, are considered. This facility is a new type of nuclear reactor, in the core of which the intensity of the nuclear...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2023
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| Cite this: | Nano-mechanisms of connection in the solid phase of tungsten and tantalum in the manufacture of a neutron source target / B.V. Borts, I.A. Vorobyov, A.Yu. Zelinsky, I.M. Karnaukhov, A.A. Lopata, A.A. Parkhomenko, I.V. Patochkin, V.I. Tkachenko // Problems of Atomic Science and Technology. — 2023. — № 2. — С. 58-63. — Бібліогр.: 17 назв. — англ. |
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Borts, B.V. Vorobyov, I.A. Zelinsky, A.Yu. Karnaukhov, I.M. Lopata, A.A. Parkhomenko, A.A. Patochkin, I.V. Tkachenko, V.I. 2023-12-10T12:55:01Z 2023-12-10T12:55:01Z 2023 Nano-mechanisms of connection in the solid phase of tungsten and tantalum in the manufacture of a neutron source target / B.V. Borts, I.A. Vorobyov, A.Yu. Zelinsky, I.M. Karnaukhov, A.A. Lopata, A.A. Parkhomenko, I.V. Patochkin, V.I. Tkachenko // Problems of Atomic Science and Technology. — 2023. — № 2. — С. 58-63. — Бібліогр.: 17 назв. — англ. 1562-6016 DOI: https://doi.org/10.46813/2023-144-058 https://nasplib.isofts.kiev.ua/handle/123456789/196103 621.771+621.791.051.4+669-1 Nano-mechanisms of solid-phase bonding of tungsten and tantalum, which are implemented in the manufacture of a neutron source target for the research nuclear facility (RNF) of NSC KIPT, are considered. This facility is a new type of nuclear reactor, in the core of which the intensity of the nuclear fission reaction of the uranium isotope ²³⁵U is controlled by an electron accelerator. An installation for joining metals in the solid phase is described, its parameters are given, as well as the parameters of the joined metals. An electron-probe X-ray spectral analysis of the interface between the samples was carried out. The physical foundations of the nano-mechanism of bonding in the solid phase of tungsten and tantalum at the dynamic and isostatic stages at hot vacuum pressing are formulated. Experimental data on the relative temperature convergence of rolls at the dynamic and isostatic stages of hot vacuum pressing have been obtained. Розглянуто наномеханізми з’єднання у твердій фазі вольфраму та танталу, що реалізуються під час виготовлення мішені нейтронного джерела для дослідницької ядерної установки НДК ПЯС ННЦ ХФТІ. Ця установка є новим типом ядерного реактора, в активній зоні якого інтенсивність протікання ядерної реакції поділу ізотопу урану ²³⁵U керується прискорювачем електронів. Описано установку для з’єднання металів у твердій фазі, наведено її параметри, так само як і параметри металів, що з’єднуються. Проведено електронно-зондовий рентгеноспектральний аналіз межі з’єднання зразків. Отримано експериментальні дані щодо температурного сходження валків на стадіях: динамічній і ізостатичного гарячого вакуумного пресування. This work was carried out at the expense of the target program of scientific research of the National Academy of Sciences of Ukraine “Nuclear and radiation technologies for the energy sector and public needs” for 2022 (КПКВК 6541030). en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Problems of Atomic Science and Technology Thermal and fast reactor materials Nano-mechanisms of connection in the solid phase of tungsten and tantalum in the manufacture of a neutron source target Наномеханізми з’єднання у твердій фазі вольфраму i танталу при виготовленні мішені нейтронного джерела Article published earlier |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| title |
Nano-mechanisms of connection in the solid phase of tungsten and tantalum in the manufacture of a neutron source target |
| spellingShingle |
Nano-mechanisms of connection in the solid phase of tungsten and tantalum in the manufacture of a neutron source target Borts, B.V. Vorobyov, I.A. Zelinsky, A.Yu. Karnaukhov, I.M. Lopata, A.A. Parkhomenko, A.A. Patochkin, I.V. Tkachenko, V.I. Thermal and fast reactor materials |
| title_short |
Nano-mechanisms of connection in the solid phase of tungsten and tantalum in the manufacture of a neutron source target |
| title_full |
Nano-mechanisms of connection in the solid phase of tungsten and tantalum in the manufacture of a neutron source target |
| title_fullStr |
Nano-mechanisms of connection in the solid phase of tungsten and tantalum in the manufacture of a neutron source target |
| title_full_unstemmed |
Nano-mechanisms of connection in the solid phase of tungsten and tantalum in the manufacture of a neutron source target |
| title_sort |
nano-mechanisms of connection in the solid phase of tungsten and tantalum in the manufacture of a neutron source target |
| author |
Borts, B.V. Vorobyov, I.A. Zelinsky, A.Yu. Karnaukhov, I.M. Lopata, A.A. Parkhomenko, A.A. Patochkin, I.V. Tkachenko, V.I. |
| author_facet |
Borts, B.V. Vorobyov, I.A. Zelinsky, A.Yu. Karnaukhov, I.M. Lopata, A.A. Parkhomenko, A.A. Patochkin, I.V. Tkachenko, V.I. |
| topic |
Thermal and fast reactor materials |
| topic_facet |
Thermal and fast reactor materials |
| publishDate |
2023 |
| language |
English |
| container_title |
Problems of Atomic Science and Technology |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| format |
Article |
| title_alt |
Наномеханізми з’єднання у твердій фазі вольфраму i танталу при виготовленні мішені нейтронного джерела |
| description |
Nano-mechanisms of solid-phase bonding of tungsten and tantalum, which are implemented in the manufacture of a neutron source target for the research nuclear facility (RNF) of NSC KIPT, are considered. This facility is a new type of nuclear reactor, in the core of which the intensity of the nuclear fission reaction of the uranium isotope ²³⁵U is controlled by an electron accelerator. An installation for joining metals in the solid phase is described, its parameters are given, as well as the parameters of the joined metals. An electron-probe X-ray spectral analysis of the interface between the samples was carried out. The physical foundations of the nano-mechanism of bonding in the solid phase of tungsten and tantalum at the dynamic and isostatic stages at hot vacuum pressing are formulated. Experimental data on the relative temperature convergence of rolls at the dynamic and isostatic stages of hot vacuum pressing have been obtained.
Розглянуто наномеханізми з’єднання у твердій фазі вольфраму та танталу, що реалізуються під час виготовлення мішені нейтронного джерела для дослідницької ядерної установки НДК ПЯС ННЦ ХФТІ. Ця установка є новим типом ядерного реактора, в активній зоні якого інтенсивність протікання ядерної реакції поділу ізотопу урану ²³⁵U керується прискорювачем електронів. Описано установку для з’єднання металів у твердій фазі, наведено її параметри, так само як і параметри металів, що з’єднуються. Проведено електронно-зондовий рентгеноспектральний аналіз межі з’єднання зразків. Отримано експериментальні дані щодо температурного сходження валків на стадіях: динамічній і ізостатичного гарячого вакуумного пресування.
|
| issn |
1562-6016 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/196103 |
| citation_txt |
Nano-mechanisms of connection in the solid phase of tungsten and tantalum in the manufacture of a neutron source target / B.V. Borts, I.A. Vorobyov, A.Yu. Zelinsky, I.M. Karnaukhov, A.A. Lopata, A.A. Parkhomenko, I.V. Patochkin, V.I. Tkachenko // Problems of Atomic Science and Technology. — 2023. — № 2. — С. 58-63. — Бібліогр.: 17 назв. — англ. |
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2025-11-26T13:43:25Z |
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2025-11-26T13:43:25Z |
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58 ISSN 1562-6016. Problems of Atomic Science and Technology. 2023. №2(144)
https://doi.org/10.46813/2023-144-058
UDC 621.771+621.791.051.4+669-1
NANO-MECHANISMS OF CONNECTION IN THE SOLID PHASE
OF TUNGSTEN AND TANTALUM IN THE MANUFACTURE
OF A NEUTRON SOURCE TARGET
B.V. Borts1, I.A. Vorobyov1, A.Yu. Zelinsky1, I.M. Karnaukhov1, A.A. Lopata1,
A.A. Parkhomenko1,2, I.V. Patochkin1, V.I. Tkachenko1,2
1National Science Center “Kharkov Institute of Physics and Technology”, Kharkiv, Ukraine;
2V.N. Karazin Kharkiv National University, Kharkiv, Ukraine
E-mail: borts@kipt.kharkov.ua
Nano-mechanisms of solid-phase bonding of tungsten and tantalum, which are implemented in the manufacture
of a neutron source target for the research nuclear facility (RNF) of NSC KIPT, are considered. This facility is a new
type of nuclear reactor, in the core of which the intensity of the nuclear fission reaction of the uranium isotope 235U
is controlled by an electron accelerator. An installation for joining metals in the solid phase is described, its
parameters are given, as well as the parameters of the joined metals. An electron-probe X-ray spectral analysis of the
interface between the samples was carried out. The physical foundations of the nano-mechanism of bonding in the
solid phase of tungsten and tantalum at the dynamic and isostatic stages at hot vacuum pressing are formulated.
Experimental data on the relative temperature convergence of rolls at the dynamic and isostatic stages of hot
vacuum pressing have been obtained.
INTRODUCTION
The nuclear research facility (NRF) under
development at NSC KIPT is a new type of nuclear
facility, in which the intensity of the nuclear fission
reaction of the uranium isotope 235U in the core is
controlled by an electron accelerator [1, 2].
The IAEA international classification of such
installations is ADS-systems (Accelerator Driven
Systems). At present, all concepts of such systems being
developed at CERN, LANL, KENS are based on the
spectrum of fast neutrons in a subcritical assembly
(SCA).
Target-converters of such generators, which convert
accelerated charged particles into high-intensity neutron
fluxes, are a very important unit, they have a number of
requirements and limitations, primarily due to the
purpose directions and technological features of the
installations. Neutrons are produced as a result of
photoneutron reactions (γ, xn) from bremsstrahlung of
electrons incident on a target of heavy nuclei. On Fig. 1
shows the dependence of the neutron yield per unit
power [3]. In the system of NRF NSC KIPT, 2 types of
targets-converters are being developed: 1) based on
tungsten and 2) based on uranium. They are used to
fabricate target plates with high heat flux and as
structural materials with high density in the radiation
environment. The NSC KIPT carried out research work
to determine and develop the optimal, from the point of
view of materials science, target material for a 100 MeV
source, a current of 1 mA and a power of 100 kW.
However, it has been found that tungsten has poor
corrosion resistance to aqueous coolants due to the
formation of fragile tungsten hydroxide [4–6] and high
susceptibility to radiation embrittlement [7]. One way to
eliminate these problems is to clad the tungsten with a
corrosion resistant material such as tantalum, titanium,
stainless steel, zircalloy, niobium, or gold.
Fig. 1. Dependence of the neutron yield per unit
power of the incident electron beam
The result of this action is an increase in resistance
to radiation damage, a decrease in low-temperature
recrystallization and radiation embrittlement. To create
a tungsten target for a neutron source, tantalum was
chosen as a protective material. In this regard, a new
task arose – to develop a technology for the production
of a target resistant to long-term exposure to an electron
beam with an energy of 100 MeV, a power of up to
100 kW and resistant to corrosion in a cooling aqueous
medium.
Previously, our studies were aimed at fabricating a
target from pure cast tungsten with a fine-grained
structure. However, they were unsuccessful, due to
intergranular cracking of the target material. The
solution to the problem was found by manufacturing
target plates from pure tungsten powder by hot vacuum
pressing.
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ISSN 1562-6016. Problems of Atomic Science and Technology. 2023. №2(144) 59
To protect the tungsten, tantalum was chosen as one
of the best materials resistants to corrosion under
irradiation in the aquatic environment.
High-purity tantalum powder was deposited on the
side surface of tungsten plates, 1.2 mm thick, from
TaCl5 powder, using the CVD method, on a specially
designed “Termit” installation.
The connection in the solid phase of flat protective
surfaces of tungsten and tantalum plates, 250 μm thick,
was carried out using an intermediate damping layer of
titanium by the following method:
a) dynamic hot rolling in vacuum;
b) isostatic pressing method using a vacuum rolling
mill.
Rolling of dissimilar metals in vacuum and at high
temperature was carried out on a vacuum rolling mill
DUO-175 [8–11]. The schematic diagram of the
installation is shown in Fig. 2.
The installation consists of a vacuum system 6
providing a vacuum 𝑝 = 10−2 . . . 10−3 Pa, a furnace
2 for heating samples to a temperature of
𝑇 1300 °C and a chamber with rolls 4 providing a
rolling speed 𝑉0 = 0.03 m/s and compression force
𝑃 = (2 … 32) ∙ 102 MPa. The radius of heat-resistant
steel rolls simultaneously rotating with the same
angular velocity in oppos.
Fig. 2. Vacuum rolling mill for joining dissimilar
materials in the solid phase: 1 – loading chamber;
2 – vacuum furnace; 3 – ceramic insulator;
4 – rolls; 5 – chamber for unloading and collecting
finished products; 6 – vacuum system consisting of a
diffusion pump 6 and fore vacuum pumps;
7, 8 – racks control of the technological process of
rolling; 9 – automated control system and control of
the technological process;
10 – weldable plate pack in the furnace;
11 – weldable plate pack in the roller chamber
To ensure the process of joining Ta-Ti-W-Ti-Ta
metals, a batch scheme for joining metals of different
hardness and plasticity was used. The rolled metals
were placed in a strong Nb alloy mandrel in the
following sequence: a W plate of different thicknesses
from 2.5 to 9.5 mm is in contact on both sides with Ti
plates 30…40 µm thick. In turn, Ti plates are in contact
with Ta plates with a thickness of 240…250 μm. The
surface W had irregularities in the form of protrusions
and recesses, obtained during processing on an
electroerosive machine. The height of the plates varied
in the range of 1.5…10 μm, and the transverse
dimensions corresponded to the length and width of the
tungsten target. The tungsten plate had the shape of a
square with a side of 65.8 mm.
The mandrel made of N holds the metals to be
joined in the solid phase with the set order
Ta-Ti-W-Ti-Ta was placed in a rolling mill according to
the scheme shown in Fig. 3.
Fig. 3. Layout of the rolls of the rolling mill
and rolled metals: 1 – rolls; 2 – Nb alloy mandrel;
3 – joined metals in the solid phase, arranged in the
order Ta-Ti-W-Ti-Ta
MODEL OF THE COMPOUND
OF TUNGSTEN, TITANIUM
AND TANTALUM BY ROLLING
IN VACUUM
In the experiment, the connection of Ta-Ti-W-Ti-Ta
by hot rolling in vacuum is carried out in two stages,
preliminarily by heating the package in a furnace to
1300 °C with an exposure of about 1 h and feeding it
under the rolls.
At the first stage of rolling, which we will call
dynamic, Ta-Ti-W-Ti-Ta layers are installed rigidly
and symmetrically with respect to the tungsten layer in a
strong Nb alloy mandrel. The mandrel is moved by
rolls. The movement of the mandrel is carried out in the
forward, reverse and again in the forward direction.
Rolling ends when the rolls are in the middle of the
mandrel.
In the second stage of rolling, the rolls remain in a
position in the middle of the mandrel, and this state is
maintained for several hours. This stage of rolling will
be called isostatic.
The experimental conditions indicate the absence of
relative motion of the rolled metals: a special mandrel
does not allow the metals to move relative to each other.
However, it transmits the force of the rolls in the
direction transverse to the speed of movement of the
metals. Due to the high pressures and rather high
temperature of the samples, Ti can pass into a quasi-
liquid state [12], while the Nb, Ta, and W alloys remain
in the solid phase.
In a microscopic measurement on a thin section
depicting the interface between W and Ti after the
dynamic stage, one can see the incomplete connection
of W and Ta through the Ti interlayer, as shown in
Fig. 4.
It follows from Fig. 4 that, immediately after the
dynamic stage of rolling, an incomplete penetration of
Ti into W occurs. An increase in the load does not lead
60 ISSN 1562-6016. Problems of Atomic Science and Technology. 2023. №2(144)
to complete filling of the cavities with titanium, but only
to uncontrolled deformation of the mandrel and the
entire package.
Fig. 4. Microphoto of the boundaries of the W,
Ti, Ta compound after the first dynamic stage.
At the interface between W and Ti, one can see
unfilled cavities in W
The cavity filling condition W was found as a result
of a series of experiments. To do this, it is necessary to
leave the package under load in a hot state, followed by
cooling. In the process of isostatic loading and when the
temperature drops from 1200...1300 to 882 °C, within
10…12 h, quasi-liquid Ti fills all depressions in W
(Fig. 5).
Fig. 5. Microphoto of the boundary of the W+Ti+Ta
compound after the second, isostatic stage of
pressing. Filled cavities in W are visible at the
interface between W and Ti
PHYSICAL MODEL OF W, Ta, AND Ti
COMPOUND BY THE METHOD OF
ISOSTATIC HOT VACUUM PRESSING
PHYSICAL BACKGROUND TO
FORMULATION OF THE COMPOUND MODEL
The properties of titanium α+β-alloys are such that,
above a temperature of 882 °C, it has superplasticity and
fluidity in the region of the β-phase [13]. On Fig. 6
shows the phase diagram of the state of a binary Ti-Ta
mixture as a function of temperature.
An analysis of the phase diagram indicates that at
the boundary of the solid-phase Ti-Ta compound under
equilibrium conditions, the sample should consist of the
α-phase of titanium and pass into the tantalum region
through the two-phase region α+β, which provides
superfluidity when all irregularities are filled in the
solid-phase connection.
The study by scanning electron microscopy of the
microstructure of the zones of the W-Ti and Ti-Ta joints
(Fig. 7), as well as in the body of the constituent
samples, showed the absence of defects in the form of
pores, delaminations, cracks or inclusions. An X-ray
electron probe microanalysis made it possible to
determine the widths of the diffusion zones for Ta-Ti
and Ti-W equal to 2 and 3 µm, respectively.
Fig. 6. Phase diagram of the state of the binary
mixture Ti-Ta as a function of temperature
The nature of the slope of the concentration curves
at the boundaries of Ta-Ti and Ti-W indicates the
predominant penetration of quasi-liquid titanium into
both tantalum and tungsten, which is explained by the
high mobility of titanium.
When an isostatic load occurs, Ti penetrates into
micro-depressions in W, and the connection in the solid
phase of the surface of Ti and W occurs along the entire
interface.
In addition, at this stage, we will assume that, in
view of the quasi-liquid state of Ti, the metal bonding
process occurs as a result of the penetration of Ti into
the roughness of the tungsten boundary. Since the
irregularities of tungsten are in a vacuum, the joining
process will be associated with the penetration of a
heavier substance (quasi-liquid Ti) into a lighter
substance (vacuum). The whole system is placed in a
force field, the effective acceleration of which 𝑔∗ is
determined by the force of volumetric compression Ti
with the Ta+Nb alloy on the one hand, and W on the
other, due to different coefficients of their thermal
expansion.
Fig. 7. Electron probe X-ray spectral analysis of
Ta-W-Ta samples (Ti interlayers) through the
boundaries of the connection: a – tantalum-
titanium and b – titanium-tungsten
ISSN 1562-6016. Problems of Atomic Science and Technology. 2023. №2(144) 61
Thus, we come to the Rayleigh-Taylor instability
problem, which describes the motion of the interface
between liquid media in a gravitational or other [14]
force field. In media with dissipation, which is the
viscosity of liquids, such instabilities are called
dissipative Rayleigh-Taylor instabilities (DRTI) [15].
To describe the process of combining titanium with
tungsten, a model description was proposed in [16]. It is
based on the use of the DRTI theory. An estimate of the
values of the parameters of a binary metal system
subjected to DRTI is given.
EXPERIMENTAL RESULTS
AND DISCUSSION
Based on the use of the DRTI model, the estimate of
the characteristic connection time turns out to be about
40 s. The validity of the model is confirmed by the
experimentally measured relative change in the diameter
of the rolls at the dynamic and isostatic stages of rolling.
The relative change in the roll gap is the difference
between the current convergence of the rolls and the
initial one, which in the experiment was chosen to be
100 µm. The initial convergence of the rolls during
rolling or isostatic hot vacuum pressing is determined
by the difference between the thickness of the Nb –
𝐻𝐴𝑠(𝑡) and the vertical distance between the
generatrixes of the upper and lower rolls – 𝐻𝑅𝑜𝑙𝑙𝑠(𝑡),
where t is time.
Due to the small, applied stresses during rolling, we
will assume that all metals, except for Ti, obey Hooke's
law, i. e. when stress is removed, they return to their
original shape. Therefore, a change in the dimensions of
rolled metals can occur as a result of linear expansion /
contraction of the samples when their temperature
changes.
The experimentally obtained relative temperature
change in the gap between the rolls at the dynamic and
isostatic stages of rolling is shown in Table.
Relative temperature convergence rolls at dynamic and isostatic stages
Dynamic stage
Time, s 0 8…9 ‒ ‒ ‒ ‒ ‒ ‒ ‒ –
Relative discrepancy, μm 0 20 ‒ ‒ ‒ ‒ ‒ ‒ ‒ –
Phase of the stage а) – – – – – – – –
Isostatic stage
Time, s – – 0 10 25 40 50 80 200 510
Relative discrepancy, μm – – 20 0 -20 -5 0 15 75 85
Phase of the stage – – b) с) d)
a) the mandrel with metals is heated, and its thickness increases, and the relative divergence of the rolls increases from
zero to 20 µm. The distance between the rolls does not change due to a small change in their temperature;
b) the assembly cools down, the rolls heat up, and Ti is still in a quasi-liquid state;
c) with a decrease in the assembly temperature, Ti passes from a quasi-liquid state to a solid state. The temperature
difference between the rolls and assembly remains quite high. Therefore, the cooling of the assembly and the heating of
the rolls can be considered as heat exchange between the heated and cold solids. Currently interval, the heating of the
assembly occurs due to the work of viscous forces arising from the thermal expansion of the assembly and rolls;
d) the temperature gradient between the rolls and the assembly decreases so much that the entire assembly of metals
St.s+Nb+Ta+Ti+W+Ti+Ta+Nb+St.s cools over time as a whole, due to radiant heat transfer. In this case, the relative
divergence of the rolls increases.
From Table, it follows that during the dynamic
stage, during rolling in the forward and reverse
directions for about 9 s, the massive rolls were in
contact along the generatrix line with the surface of the
heated assembly over a rolling length of 10 cm, which
corresponds to the rolling of the rolls clockwise and in
the opposite direction by angle 67.44º. As a result of
such contact, the rolls heat up slightly, and the
assembly, in preparation for rolling, is preheated in the
furnace to 1300 °C. During rolling, the rolls are heated,
because of plastic deformation of the rolled package, so
that the relative convergence with an external increase
in the diameters of the rolls at the isostatic stage will
increase to 20 μm. The increase in the assembly
temperature in this case is estimated at about 25…30 ºС
[17]. Then, at the isostatic stage, the rolls are heated
through the area of contact with the package assembly,
and the assembly of Nb+Ta+Ti+W+Ti+Ta+Nb metals is
cooled in accordance with their thermal conductivity
coefficients.
Thus, because of the cooling process of the assembly
and heating of the rolls and, accordingly, their increase
in diameter, during the isostatic stage, volumetric
thermal compression of the assembly is observed, and a
decrease in pressure in Ti, which is still in a quasi-liquid
state for a certain time. This stage, as shown by
experiment and numerical evaluation, lasts on the order
of several tens of seconds. During this time, the
tungsten cavities are filled with quasi-liquid titanium
because of the development of DRTI [16].
After that, the rolls continue to heat up, and as a
result of their volumetric thermal expansion, the force
of isostatic vacuum pressing of the package assembly is
increased. After a long period of cooling (about 12 h) of
the entire system, Ti passes into the solid phase, and the
process of joining Ti+W is completed.
On Fig. 8 shows a graph of the relative change in the
diameter of the rolls from the time of rolling, in the
dynamic and isostatic stages. It follows from this figure
that the experimentally measured time for changing the
62 ISSN 1562-6016. Problems of Atomic Science and Technology. 2023. №2(144)
gap between the rolls and decreasing the pressure in Ti
corresponds to the characteristic time for the
development of DRTI.
CONCLUSIONS
The article deals with the manufacture of a target-
converter for the RNF under development at NSC
KIPT, which is a new type of nuclear reactor, in the
core of which the intensity of the nuclear fission of the
uranium 235U isotope is controlled by an electron
accelerator. The process of joining W with Ta in the
solid phase with the help of a Ti interlayer by the
vacuum rolling method is considered. To facilitate the
process of joining these metals, it is proposed to use the
previously developed batch scheme for joining metals
of different hardness and plasticity. The combination of
W and Ta by rolling in a vacuum is carried out in two
stages. The first is the dynamic stage of rolling. The
second is the isostatic stage of pressing the W and Ta
compound by rolling in vacuum, controlled by nano-
mechanisms with the appropriate temperature-force
parameters. A scheme has been developed for rolling a
mandrel made of niobium with joined metals in the
solid phase. An electron-probe X-ray spectral analysis
of the boundary between the titanium-tungsten and
titanium-tantalum junctions has been carried out. The
predominant diffusion penetration of titanium into
tantalum and tungsten is shown. The stages of the
physical foundations of nano-mechanisms of joining in
the solid phase of tungsten and tantalum at the dynamic
and isostatic stages of hot vacuum pressing are
determined. Experimental data on the relative
temperature convergence of the rolls at these stages
have been obtained.
ACKNOWLEDGEMENTS
This work was carried out at the expense of the
target program of scientific research of the National
Academy of Sciences of Ukraine “Nuclear and radiation
technologies for the energy sector and public needs” for
2022 (КПКВК 6541030).
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a; b; c; d
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Article received 21.02.2023
НАНОМЕХАНІЗМИ З’ЄДНАННЯ У ТВЕРДІЙ ФАЗІ ВОЛЬФРАМУ I ТАНТАЛУ
ПРИ ВИГОТОВЛЕННІ МІШЕНІ НЕЙТРОННОГО ДЖЕРЕЛА
Б.В. Борц, I.А. Воробйов, А.Ю. Зелінській, І.М. Карнаухов, А.А. Лопата, О.О. Пархоменко,
І.В. Паточкін, В.І. Ткаченко
Розглянуто наномеханізми з’єднання у твердій фазі вольфраму та танталу, що реалізуються під час
виготовлення мішені нейтронного джерела для дослідницької ядерної установки НДК ПЯС ННЦ ХФТІ. Ця
установка є новим типом ядерного реактора, в активній зоні якого інтенсивність протікання ядерної реакції
поділу ізотопу урану 235U керується прискорювачем електронів. Описано установку для з'єднання металів у
твердій фазі, наведено її параметри, так само як і параметри металів, що з'єднуються. Проведено
електронно-зондовий рентгеноспектральний аналіз межі з'єднання зразків. Отримано експериментальні дані
щодо температурного сходження валків на стадіях: динамічній і ізостатичного гарячого вакуумного
пресування.
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