Formation of a layered structure of a metal strengthening zone under irradiation with the pulsed high-current electron beam
Gespeichert in:
| Veröffentlicht in: | Вопросы атомной науки и техники |
|---|---|
| Datum: | 2001 |
| 1. Verfasser: | |
| Format: | Artikel |
| Sprache: | English |
| Veröffentlicht: |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2001
|
| Online Zugang: | https://nasplib.isofts.kiev.ua/handle/123456789/79268 |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Zitieren: | Formation of a layered structure of a metal strengthening zone under irradiation with the pulsed high-current electron beam / Yu.E. Kolyada // Вопросы атомной науки и техники. — 2001. — № 3. — С. 184-186. — Бібліогр.: 10 назв. — англ. |
Institution
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
nasplib_isofts_kiev_ua-123456789-79268 |
|---|---|
| record_format |
dspace |
| spelling |
Kolyada, Yu.E. 2015-03-30T08:29:50Z 2015-03-30T08:29:50Z 2001 Formation of a layered structure of a metal strengthening zone under irradiation with the pulsed high-current electron beam / Yu.E. Kolyada // Вопросы атомной науки и техники. — 2001. — № 3. — С. 184-186. — Бібліогр.: 10 назв. — англ. 1562-6016 PACS nambers: 29.17.+w https://nasplib.isofts.kiev.ua/handle/123456789/79268 The author thanks Ermolenko B.F. and Senderovich G.A. for the help in carrying out the experiments, Pogrebnoy N.A. for conducting the metallographic examinations, Ilyinsky A.I. and Fedun V.I. for arguing the results. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Formation of a layered structure of a metal strengthening zone under irradiation with the pulsed high-current electron beam Образование слоистой структуры упрочнённой зоны металла при облучении импульсным сильноточным электронным пучком Article published earlier |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| title |
Formation of a layered structure of a metal strengthening zone under irradiation with the pulsed high-current electron beam |
| spellingShingle |
Formation of a layered structure of a metal strengthening zone under irradiation with the pulsed high-current electron beam Kolyada, Yu.E. |
| title_short |
Formation of a layered structure of a metal strengthening zone under irradiation with the pulsed high-current electron beam |
| title_full |
Formation of a layered structure of a metal strengthening zone under irradiation with the pulsed high-current electron beam |
| title_fullStr |
Formation of a layered structure of a metal strengthening zone under irradiation with the pulsed high-current electron beam |
| title_full_unstemmed |
Formation of a layered structure of a metal strengthening zone under irradiation with the pulsed high-current electron beam |
| title_sort |
formation of a layered structure of a metal strengthening zone under irradiation with the pulsed high-current electron beam |
| author |
Kolyada, Yu.E. |
| author_facet |
Kolyada, Yu.E. |
| publishDate |
2001 |
| language |
English |
| container_title |
Вопросы атомной науки и техники |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| format |
Article |
| title_alt |
Образование слоистой структуры упрочнённой зоны металла при облучении импульсным сильноточным электронным пучком |
| issn |
1562-6016 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/79268 |
| citation_txt |
Formation of a layered structure of a metal strengthening zone under irradiation with the pulsed high-current electron beam / Yu.E. Kolyada // Вопросы атомной науки и техники. — 2001. — № 3. — С. 184-186. — Бібліогр.: 10 назв. — англ. |
| work_keys_str_mv |
AT kolyadayue formationofalayeredstructureofametalstrengtheningzoneunderirradiationwiththepulsedhighcurrentelectronbeam AT kolyadayue obrazovaniesloistoistrukturyupročnennoizonymetallaprioblučeniiimpulʹsnymsilʹnotočnymélektronnympučkom |
| first_indexed |
2025-11-25T03:53:19Z |
| last_indexed |
2025-11-25T03:53:19Z |
| _version_ |
1850505751274979328 |
| fulltext |
FORMATION OF A LAYERED STRUCTURE OF A METAL
STRENGTHENING ZONE UNDER IRRADIATION WITH THE
PULSED HIGH-CURRENT ELECTRON BEAM
Yu.E. Kolyada
Priasovsky State Technical University
Mariupol, Ukraine
PACS numbers: 29.17.+w
Use of pulsed high-current beams of charged parti-
cles finds wide application for hardening the surface of
metals and alloys [1, 2].
Modification of surface properties of metals and al-
loys by concentrated streams of energy, and electron
beams, in particular, is stipulated by the following
mechanism. As a result of their interaction with a pro-
cessed material there is a flash heat (up to a melting
temperature and higher) of the surface stratum with sub-
sequent cooling at enough high velocity (106-107 K/c),
that as a rule, results in essential changes of the struc-
ture and properties as compared to the initial state. As a
result of a temper the martensite with fine-dispersed
grains is formed from a liquid phase of the metal on a
surface. The microhardness of the formed stratum in
comparison with a starting material is incremented in
several times. Thus its operational performances raise: a
wear hardness, a corrosion stability etc.
In spite of the fact that the given technologies are
widely put into practice, the physics of formation of the
modified surface stratum of a material under activity of
high-current electron beams is insufficiently investigat-
ed. Periodic character of the strengthened stratum deep
into a sample (change of a microhardness and structure
of a material) [1, 3, 4] in some cases is observed.
In the given paper results of experimental research
on interaction of pulsed electron beams in a wide range
of energies (from 50 to 500 keV) with iron-based alloys
are presented. Requirements for layered structure for-
mation in the strengthened metal band are studied.
As radiants of electron beams used were the follow-
ing systems. The low-energy high-current beam was
shaped in a direct discharge through gases at a low pres-
sure with a cold cathode. Similar systems are described
in [5]. Parameters of the beam produced are: current up
to 5.103 А, energy 30-50 keV, pulse length ~ 2 μs. The
diameter of a beam does not exceed 2 cm. For deriving
the high-energy beam the accelerator of a direct action
with a cold cathode was used, its detailed schematic lay-
out is given in [6]. Parameters of a used beam are: ener-
gy - up to 500 keV, current - up to 10 kА, pulse length
10-15 μs, diameter of a beem - up to 10 cм. Samples of
carbon steel in the annealed state and of alloyed steel in
a tempered condition were exposed to irradiation. Di-
mensions of samples were 10×10×55 mm.
In Fig. 1 (1-3) the photos of the cross metallographic
samples are submitted to alloyed steel, undergone single
irradiation with a high-energy beam of the 300 keV en-
ergy. Photos are obtained at the coefficient of magnifi-
cation 200. In photos 2 and 3 the layered structure fol-
lowing the surface white stratum is distinctly visible. It
is necessary to note, that a spatial period of stratums
about depth of a white stratum (~10 microns) is ob-
tained as a result of melting and subsequent prompt
cooling.
1 2 3
Fig. 1. Cross-sections of metallographic samples of
alloyed steel, undergone to single irradiation with a
high-energy beam of 300 keV energy.
Periodic character of the strengthened stratum is evi-
denced also with a microhardness testing deep into a
sample, carried out by the Vickers method. The depen-
dence mentioned is shown in Fig. 2.
0
1000
2000
3000
4000
5000
6000
7000
8000
0 20 40 60 80 100 mkm
МPа
Fig. 2. Distribution of a microhardness of the strength-
ened stratum deep into a sample.
In a photo presented in Fig. 1 (1) a layered structure,
practically, is not observed. The given mode of irradia-
tion differs from previous - 2 and 3 thus in the given ex-
perience the requirement of an ablation is not fulfilled.
When an ablation develops there is the intensive transpi-
ration of a target that results in an additional impulse of
pressure. This appearance takes place, if the energy flux
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 2001. №3.
Серия: Ядерно-физические исследования (38), с. 184-186.
184
density exceeds the critical quantity q which is deter-
mined from relations [7]:
Tkq
χ
πτ
2
= , 2/1)(χ τδ < < ,
(1)
Tkq
χ
δτ = , 2/1)(χ τδ > > ,
where χ and k are the coefficients of temperature and
heat conductivity, respectively, RT λ1.0≥ - temper-
ature relevant to a kickoff of intensive transpiration. λ
- molar latent heat of vaporization, R - universal gas
constant, δ - depth of losses of energy particles of a
beam. For alloys of iron it is possible to accept
Kм
Wk .60= , Т equals approximately to the temper-
ature of sublimation. For estimation of depth of losses
(cm) it is possible to use the known formula [8] down to
the energy of a beam 3.103 keV:
2/3510 U−=ρ δ . (2)
Here ρ - density in g/cm3, U - accelerating voltage
in kV. In requirements of experience the case is imple-
mented, i.e. for parameters of a beam (energy
~ 300 keV, a current ~ 8 kА, a pulse length ~ 10 sµ ) it is
necessary to use the inferior expression of relations (1).
Quantity q appears equal to ~ 1-2 .107 W/sm2. The used
beam can transfer a stream of a power from 107 up to
8.108 W/cm2. In the given accelerator to control a stream
of power in so wide range of values appeared possible
due to magnetic squeezing of the aperture of the beam
secti. The mode implemented during irradiation of a
sample, presented in the photo of Fig.1 (1), is obtained
in case of the beam diameter above 10 cm. Thus, the
stream of power on a metal surface was below
107 W/cm2.
The cause of a layered structure formation in case of
Fig. 1 (2, 3), most likely, is shaping an intensive stand-
ing ultrasonic wave in thickness of a sample (thickness
was 1 cm). Really, it is possible, by reaching the consid-
erable pressures up to 109 Pa and higher [7] in case of
ablation development, to observe beam interaction with
a surface of metal in the surface white stratum (a white
stratum in the photos presented). It is also confirmed in
[9] and in a number of other papers. In the sample thick-
ness under action of an intensive ultrasonic field of a
standing wave there is a mechanical hardening of metal
which is especially exhibited only in heat areas, since in
a cold part of a sample the yield strength of the given al-
loy is higher than possible accessible quantities of pres-
sure for the given beam parameters. The yield strength
for a cold metal is 1.2-2.8.109 Pa. As is known, the yield
strength decreases with temperature increasing.
Frequency and length of a standing wave, obviously,
determine thickness of the fused stratum. It is the res-
onator which is excited by a particle beam at a natural
frequency
l
ncf n 2
= , (3),
where n - the number of harmonics, c - sound velocity ,
l - cross size of the resonator (thickness of the fused
stratum). It is equal to requirements of experience of 10
microns. In this case the normal oscillations are raised
in the resonator [10], and the same oscillations are
raised also in the remaining sample thickness due to the
ultrasonic connection. For a first harmonic the frequen-
cy can be equal to ~2.108 Hz that is a hypersonic range.
An attempt was undertaken to register these oscilla-
tions. For this purpose the ultrasonic waveguide - an
iron core of a diameter 0.5 cm and length 0.5 m which
fulfilled a role of a line of an acoustic delay, was fas-
tened to the end face of a sample. The lag line was nec-
essary for a time outcome under the relation to time of
beam-target interaction. During the impulse of beam-
target interaction it is inconvenient to carry out the indi-
cated measuring in connection with a high level of nois-
es. The wave train of the registered ultrasonic oscilla-
tions is shown in Fig. 3. The reference frequency of
high-frequency oscillations will be as much as
200 МHz. Oscillations are aperiodic. Aperiodicity may
be stipulated, as signal attenuation in the used wave-
guide, and in the sample.
Fig. 3. Wave train of the registered ultrasonic oscilla-
tions
With the purpose of checking out the guess that the
melting stratum is a ultrasonic system in which elastic
oscillations are raised initially with the subsequent dis-
tribution to thickness of a sample original, experiments
with a low-energy (~ 50 keV) beam were carried out.
The results of the experiment with carbon steel are giv-
en by a number of photos in Fig. 4 (1,2). The photo 4
(1) was obtained at coefficient of magnification 200,
and 4 (2) - 450.
1 2
Fig. 4. Cross-sections of metallographic samples of
carbon steel, undergone to single irradiation with a
beam of 50 keV energy.
185
The thickness of a white stratum (the fused metal) is
about a micron that coincides with a period of a layered
structure which is distinctly visible in both photos. The
periodic structure is observed only in a depth 5-7 mi-
crons. It is explained by that the depth of penetration of
heat h during existence of elastic oscillations (this time
is equal to a pulse duration of a beam τ ~2 sµ ) is de-
termined by the heat conductivity of a material
2/1)(~ χ τh , (4)
The depth of the strengthened stratum is about 40-
60 mµ . Examinations showed the dependence of the
microhardness of a sample on the depth (in the paper
this dependence is not given).
Thus, the experiments performed allow to get the
more complete notion about the mechanism of intense
pulsed electron beam interaction with metals and alloys.
If the stream of power beam does not cause an ap-
pearance of an ablation, the surface thermal hardening
of the metal takes place due to heating (up to a melting
temperature and higher) and subsequent cooling at a
rather high rate (106-107К/с), resulting in essential
change of the structure and properties as compared to
the initial state. As a result of a temper the martensite
with fine-dispersed grains is formed from a liquid phase
of metal on a surface. The microhardness of the formed
stratum in comparison with a starting material increases
in several times. This is described in details, for exam-
ple, in [1, 2].
If the energy flux density of a beam exceeds some
critical value there is an appearance of an ablation that
leads to the intensive transpiration of a target and to the
additional impulse of pressure [7]. As the experiments
performed showed, in the fused blanket the normal os-
cillations at one of the natural frequencies are raised.
Due to the ultrasonic communication oscillations are
spread deep into the sample in which the standing wave
appears. Its length is determined by the depth of the
fused blanket. Time of existence of oscillations, obvi-
ously, is determined by the beam pulse. Therefore as a
result of joint action of a temperature field and a ultra-
sonic standing wave in the sample there is an appear-
ance of a mechanical hardening. The depth joint action
of these factors is determined by the depth penetration
of heat during beam pulse. The appearance of a mechan-
ical hardening under action of the excited ultrasonic
wave takes place only in enough heated areas. Therefore
in deep stratums it is not exhibited. After extinction of a
beam action ultrasonic oscillations damp, distribution of
a temperature field is prolonged on a greater depth, re-
sulting in deep hardening of a metal sample that is more
common for the accepted model. However formation of
a layered structure thus does not happen.
The author thanks Ermolenko B.F. and
Senderovich G.A. for the help in carrying out the exper-
iments, Pogrebnoy N.A. for conducting the metallo-
graphic examinations, Ilyinsky A.I. and Fedun V.I. for
arguing the results.
REFERENCES
1 A.N.Didenko, A.E.Ligachyov, I.B.Kurakin.
Charged particle beam action on a surface of met-
als and alloys. Moscow: Energoatomizdat, 1987,
184 p. (in Russian).
2 N.N.Rykalin, А.N.Uglov, I.V.Zuev, A.N.Kokora.
Laser and beam handling material. Moscow:
Mashinostroenie, 1985, 496 p. (in Russian).
3 V.V.Itin, B.A.Koval' et al. The face hardening of
alloys on the basis of iron an intensive pulsed elec-
tron beam // Proc. of the 5th USSR Symposium on
High-Current Electronics. Tomsk, 1984. v. 2,
p. 141-143 (in Russian).
4 P.L.Gruzin, V.Yu.Fomichyov et al. Shaping of the
strengthened bands in iron under activity of a
pulsed beams of electrons // Proc. of the 5th USSR
Symposium on High-Current Electronics, Tomsk,
1984. v. 2, p. 150-151 (in Russian).
5 E.I.Lutsenko, N.D.Sereda, L.M.Kontsevoy. Investi-
gation of dynamics of electron beam formation in
Z-charge // Zhurnal Ehksperimentalnoy i Teo-
reticheskoy Fiziki. 1974, v. 67, # 3, p. 979-989 (in
Russian).
6 Yu.E.Kolyada. High-current diode intended for
work in open air // Proceedings of the 18th Interna-
tional Symposium on Discharges and Electrical In-
sulation in Vacuum, Eindhoven, the Netherlands,
August 17-21, 1998, v. 2, p. 696-699.
7 V.I.Golota, V.I.Karas. About the mechanism of ex-
citation of elastic oscillations in substance by
charged particle beams // Ukrainskiy Fizicheskiy
Zhurnal. 1985, v. 30, # 7, p. 1083-1097 (in Ukraini-
an).
8 V.F.Kovalenko. About calculation of a depth of
electron penetration // Electronnaya Technika.
Seriya 1: Electronika SVCH. 1972, # 1, p. 3-11 (in
Russian).
9 B.A.Demidov, M.V.Ivkin et al. Dynamics of a dis-
persion of the anode metal papers irradiated with
high-current REB // Zhurnal Technicheskoy Fiziki.
1984, v. 5, # 1, p. 155-161 (in Russian).
10 G.S.Gorelik. Oscillations and waves. Moscow: Go-
sudarstvennoe izdanie fiziko-matematicheskoy lit-
eratury, 2 Edition, 1959. 358 p. (in Russian).
|