Microstructure and mechanical properties of oxide dispersion strengthened high-entropy alloys CoCrFeMnNi and CrFe₂MnNi
High-entropy alloys (HEAs) CoCrFeMnNi and CrFe₂MnNi, dispersion-strengthened by pre-synthesized nanooxides composition of 80%Y₂O₃+20%ZrO₂ (mol.%) were obtained by mechanical alloying followed by compaction and sintering. Average grain size of the oxide dispersion-strengthened (ODS) alloys was about...
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| Опубліковано в: : | Вопросы атомной науки и техники |
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| Дата: | 2021 |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2021
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Microstructure and mechanical properties of oxide dispersion strengthened high-entropy alloys CoCrFeMnNi and CrFe₂MnNi / I.V. Kolodiy, O.M. Velikodnyi, M.A. Tikhonovsky, V.N. Voyevodin, O.S. Kalchenko, R.L. Vasilenko, V.S. Okovit // Problems of Atomic Science and Technology. — 2021. — № 2. — С. 87-94. — Бібліогр.: 26 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859950718194024448 |
|---|---|
| author | Kolodiy, I.V. Velikodnyi, O.M. Tikhonovsky, M.A. |
| author_facet | Kolodiy, I.V. Velikodnyi, O.M. Tikhonovsky, M.A. |
| citation_txt | Microstructure and mechanical properties of oxide dispersion strengthened high-entropy alloys CoCrFeMnNi and CrFe₂MnNi / I.V. Kolodiy, O.M. Velikodnyi, M.A. Tikhonovsky, V.N. Voyevodin, O.S. Kalchenko, R.L. Vasilenko, V.S. Okovit // Problems of Atomic Science and Technology. — 2021. — № 2. — С. 87-94. — Бібліогр.: 26 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | High-entropy alloys (HEAs) CoCrFeMnNi and CrFe₂MnNi, dispersion-strengthened by pre-synthesized nanooxides composition of 80%Y₂O₃+20%ZrO₂ (mol.%) were obtained by mechanical alloying followed by compaction and sintering. Average grain size of the oxide dispersion-strengthened (ODS) alloys was about 2 μm. Oxide precipitates in alloys are characterized by the presence of small particles with an average size of about 10 nm and a density of ≈ 10²¹ m⁻³, as well as small amount of larger particles sizes of 50…150 nm. The qualitative composition of particles of different sizes has been established. Mechanical properties of HEAs were studied at different temperatures. It is shown that strengthening of the studied alloys by nanooxide particles leads to a significant increase in strength characteristics.
Методом механічного легування з наступним компактуванням та спіканням отримано високоентропійні сплави CoCrFeMnNi та CrFe₂MnNi, що зміцнені попередньо синтезованими нанооксидами складу 80%Y₂O₃+20%ZrO₂ (mol.%). Середній розмір зерен у дисперсно-зміцнених сплавах близько 2 мкм. Оксидні виділення в сплавах характеризуються присутністю дрібних часток з середнім розміром близько 10 нм і щільністю ≈ 10²¹ м⁻³, а також незначної кількості більших часток з розмірами 50…150 нм. Встановлено якісний склад часток різного розміру. Досліджені механічні властивості сплавів при різних температурах. Показано, що міцнісні характеристики суттєво підвищуються при зміцненні сплавів нанооксидними частками.
Методом механического легирования с последующим компактированием и спеканием получены высокоэнтропийные сплавы CoCrFeMnNi и CrFe₂MnNi, дисперсно-упрочненные предварительно синтезированными нанооксидами состава 80%Y₂O₃+20%ZrO₂ (mol.%). Средний размер зерен в дисперсно-упрочненных сплавах составил примерно 2 мкм. Оксидные выделения в сплавах характеризуются наличием мелких частиц со средним размером около 10 нм и плотностью ≈ 10²¹ м⁻³, а также незначительного количества больших частиц с размерами 50…150 нм. Установлен качественный состав частиц разного размера. Исследованы механические свойства сплавов при разных температурах. Показано, что прочностные характеристики значительно повышаются при упрочнении сплавов нанооксидными частицами.
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| first_indexed | 2025-12-07T16:16:25Z |
| format | Article |
| fulltext |
ISSN 1562-6016. ВАНТ. 2021. №2(132) 87
https://doi.org/10.46813/2021-132-087
UDC 620.187:621.039.53
MICROSTRUCTURE AND MECHANICAL PROPERTIES OF OXIDE
DISPERSION STRENGTHENED HIGH-ENTROPY ALLOYS
CoCrFeMnNi AND CrFe2MnNi
I.V. Kolodiy
1
, O.M. Velikodnyi
1
, M.A. Tikhonovsky
1
, V.N. Voyevodin
1,2
, O.S. Kalchenko
1
,
R.L. Vasilenko
1
, V.S. Okovit
1
1
National Science Center “Kharkov Institute of Physics and Technology”, Kharkiv, Ukraine;
2
V.N. Karazin Kharkiv National University, Kharkiv, Ukraine
E-mail: kolodiy@kipt.kharkov.ua
High-entropy alloys (HEAs) CoCrFeMnNi and CrFe2MnNi, dispersion-strengthened by pre-synthesized
nanooxides composition of 80%Y2O3+20%ZrO2 (mol.%) were obtained by mechanical alloying followed by
compaction and sintering. Average grain size of the oxide dispersion-strengthened (ODS) alloys was about 2 μm.
Oxide precipitates in alloys are characterized by the presence of small particles with an average size of about 10 nm
and a density of ≈ 10
21
m
-3
, as well as small amount of larger particles sizes of 50…150 nm. The qualitative
composition of particles of different sizes has been established. Mechanical properties of HEAs were studied at
different temperatures. It is shown that strengthening of the studied alloys by nanooxide particles leads to a
significant increase in strength characteristics.
Development of the next generation nuclear reactors
imposes increased requirements on structural materials.
So an actual problem of reactor materials science is the
development of novel class of high-performance
structural materials with high radiation resistance and
improved mechanical and corrosion characteristics.
Oxide dispersion-strengthened (ODS) ferritic-
martensitic and austenitic steels [1–7], which can be
used up to damaging doses above 180 dpa, are
considered as promising structural materials for nuclear
energy applications. But recent theoretical research
activities and previous experimental results show that
so-called high-entropy alloys (HEAs) [8, 9] are the
other promising class of radiation-resistant materials.
Typically HEAs contain four, five or more elements
with equal or close concentrations. Entropy of mixing
increases significantly with a large number of elements
in the alloys and their high concentration, which
contributes to the formation of substitutional solid
solutions [8]. HEAs are characterized by strong lattice
distortion caused by the difference in atomic radii of
dissolved elements, which affects the solid-solution
hardening [10], as well as sluggish diffusion, as
vacancies associated with atoms of dissolved elements
form stable “atom-vacancy” complexes [11]. Some
HEAs show attractive mechanical properties for
practical usage. Exactly because of this reason HEAs
are considered as a promising material for structural
applications both at cryogenic and elevated
temperatures [12, 13].
Research of HEAs is mainly focused on single-phase
solid solutions with simple crystal lattices – FCC [9] or
BCC [14]. Classic HEA CoCrFeMnNi [9] attracted a lot
of attention as one of the most promising material in
terms of mechanical properties, especially at cryogenic
temperatures [15, 16]. The strength of this alloy was
increased both by thermal-mechanical treatment [17]
and by a more complex method – gas-atomized powder
was processed by mechanical milling and spark plasma
sintering [18]. The use of planetary high-energy milling
[19, 20] followed by spark plasma sintering also leads to
a significant increase in the strength of the alloy, but at
the same time plasticity decreases. Also there are other
approaches to increase strength of HEAs.
In this work we used approach [21] that proved itself
in creation of oxide dispersion-strengthrned steels [6, 7],
namely, strengthening of HEAs by thermodynamically
and radiation-resistant nanooxides by mechanical
alloying and followed compaction and sintering.
Exactly this approach can be considered as an
alternative to optimize the composition and
microstructure of existing austenitic or ferritic-
martensitic steels [22–24].
Therefore the aim of this work is to study the
structure and mechanical properties of ODS HEAs
mechanically alloyed by nanooxides of Y2O3-ZrO2
system. Moreover, for the study we chose alloys, the
behavior of which had been previously studied under
radiation exposure [25] and under corrosion in molten
lead [26].
MATERIALS AND METHODS
The research was carried out on two compositions of
HEAs with different element contents (atomic
percentages are indicated) – classic five-component
Cantor alloy CoCrFeMnNi (E3), as well as cobalt-free
four-component alloy CrFe2MnNi (E32). The absence
of cobalt in E32 alloy is important for its possible
application in conditions of radioactive exposure, since
cobalt has high induced activity and very long half-life.
The alloys were obtained by arc melting with a non-
consumable tungsten electrode in pure argon. The purity
of initial components was not less than 99.9%. To
ensure homogeneity ingots were remelted at least 5
times, the size of ingots was 6×15×60 mm. Powders of
HEA were obtained by mechanical grinding using
abrasives, and then powders were sieved into fractions.
Powders with close to equiaxial shape and less than
88 ISSN 1562-6016. ВАНТ. 2021. №2(132)
300 μm in size were used for further operations. Oxide
dispersion strengthening was carried out by mechanical
alloying. 0.5 wt.% of pre-synthesized nanopowders
composition of 80%Y2O3+20%ZrO2 (mol.%) were used
as alloying components. The synthesized powders had
cubic structure with lattice parameter a = 10.2 Å,
average size was about 17 nm.
Mechanical alloying of HEA with nanooxides was
performed by high-energy planetary ball-milling in
argon inert atmosphere. Milling time in most
experiments was 4 h. Other parameters of the milling
process are similar to those used in [7]. Obtained
powder consisted of agglomerated particles with
multimodal distribution and significant size variations
(from few microns to 500 μm and more). Subsequently
a fraction with size of < 300 μm was used in the work.
All mechanical processing operations, from powders
pressing (compacting) to compact billet rolling, were
carried out at room temperature. Wherein, mechanical
treatments were alternated with short-term annealing
(sintering) in vacuum at 1373 K. As a result tapes of
ODS HEAs 200 μm thickness were obtained. The same
tapes were obtained by rolling the original as-cast and
homogenized at 1373 K blanks of both alloys. Before
preparation for structural studies and tensile tests
samples were finally annealed at 1273 K to relieve
stresses and form the final microstructure.
Mechanical tests were carried out under active
tension at a rate of 10
-3
s
-1
on flat dumbbell shaped
specimens with the dimensions of the working section
0.2 × 1.0 × 6 mm, cut by the electric spark method from
tapes in the rolling direction. Microstructural studies
were carried out on metallographic inversion
microscope Olympus GX51 and scanning electron
microscope JSM 7001F equipped with the system for
energy-dispersive X-ray spectroscopy INCA ENERGY
350. The fine structure of samples was studied on
transmission electron microscope JEM-2100
(accelerating voltage 200 kV) equipped with scanning
attachment BF-STEM JEOL EM-24511 and energy-
dispersive X-ray microanalyzer JEOL EX-24063 JGP.
X-ray diffraction study was carried out using DRON-4-
07 diffractometer in Bragg-Brentano geometry using
Cu-Kα radiation and scintillation detector.
RESULTS AND DISCUSSION
In the initial as-cast state ingot of five-component
HEA СоCrFeNiMn has dendritic structure. Dendritic
regions are enriched in Co, Cr, and Fe and have reduced
content of Mn and Ni (Table 1). The ingot of the four-
component CrFe2MnNi HEA does not have a
pronounced dendritic structure. Results on elemental
analysis of different structural elements for both HEAs
are given in Table 1.
Table 1
Chemical composition (at.%) of as-cast alloys
E3 and E32
Elements Co Cr Fe Ni Mn
Alloy Е3 (20Co-20Cr-20Fe-20Mn-20Ni)
Actual
composition
19.4 20.9 21.2 19.1 19.4
Dendrites 21.0 21.8 22.1 16.7 16.4
Interdendritic
space
16.8 17.0 16.7 22.9 26.6
Alloy Е32 (20Cr-40Fe-20Mn-20Ni)
Actual
composition
– 19.1 41 19.8 20.1
Homogenizing annealing at 1373 K led to the
disappearance of the dendritic structure, and the grain
composition was close on average to the composition of
the as-cast ingot. Further ingots were rolled at room
temperature with intermediate annealing at 1373 K and
final annealing at 1273 K. Microstructure of the studied
alloys after thermal treatment is shown in Fig. 1. As it
can be seen, final annealing at 1273 K led to the
formation of the grain structure with an average grain
size of more than 10 μm. In case of alloy E3 some
amount of annealing twins and dislocations is observed,
whereas in alloy E32 they are almost absent.
Е3 Е32
Fig. 1. Grain microstructure of alloys E3 and E32 annealed at 1273 K for 1 hour
Next investigated HEAs were subjected to
dispersion strengthening by Y2O3-ZrO2 nanooxides.
Main parameters for the radiation resistance of ODS
HEAs are the structural-phase state, the size and density
of oxide precipitates, the composition of oxides and the
state of the “matrix-oxide” interface. The presence of
elements that can bind oxygen (e.g. Cr, Mn) in alloys
composition also plays significant role on structure
formation and properties of ODS HEAs. Microstructure
of ODS HEA E3 after final annealing at 1273 K is
shown in Fig. 2. The microstructure is characterized by
fine grains (see Fig. 2,a) and precipitates of two types
(see Fig. 2,b). First of all, these are large particles size
of 50…150 nm. In areas of their accumulation mainly
small subgrains are observed. Such large particles are
present both at the boundaries and inside the grains. The
second type of precipitates is small particles size of
~ 10 nm and density up to ~ 10
21
m
-3
(see Fig. 2,b).
ISSN 1562-6016. ВАНТ. 2021. №2(132) 89
a
b
Fig. 2. Microstructure of ODS HEA Е3 types after final annealing at 1273 K for 1 h
After final annealing grain boundaries became clear
and it can be seen that their growth is limited by
precipitates. In areas of precipitates accumulation the
grain size is ≤ 1 μm, while in areas with a smaller
number of precipitates the grain size reaches 5 μm. It
should be noted that there is a significant number of
annealing twins (see Fig. 2,a) in the microstructure of
ODS alloy E3, as in the strips of “pure”, i.e. ordinary E3
alloy (see Fig. 1).
Microstructure of the ODS HEA E32 (Fig. 3) after
final annealing at 1273 K is similar to the micro-
structure of the ODS HEA E3. It also contains
precipitates of various sizes.
a
b
Fig. 3. Microstructure of ODS HEA Е32 types after final annealing at 1273 K for 1 h
First of all, these are large precipitates up to 150 nm
in size, which are present after annealing at both
temperatures. These large particles are present both
inside the grains body and at the boundaries. In addition
to a small number of medium size precipitates (up to
50 nm) there is significant number of small precipitates
size of about 10 nm and density of ~ 10
21
m
-3
. A
characteristic feature of both ODS alloys is the uneven
volume distribution of oxide precipitates, which is
clearly shown in Figs. 2, 3. Also note the absence or
small amount of small precipitates in areas around the
large precipitates (see Fig. 3,b). That is, in this local
areas all oxygen atoms are spent on "building" this type
of oxide precipitate.
To determine the type of precipitates the elements
distribution in the matrix and precipitates was studied
(Fig. 4).
Uniform distribution of the main elements is
observed throughout the entire volume of the matrix.
The composition of precipitates was different. Some
precipitates are practically free of Fe and Ni, while
others are characterized by significant amounts of Cr
and Mn. Most of the precipitates contain a significant
content of yttrium and zirconium, as well as austenitic
steel, which was strengthened by the same nanooxides
of the Y - Zr - O system [7]. But it is also seen that Y
and Zr based oxides precipitates correlate with an
increase in the intensity of Cr and Mn, indicating the
multicomponent composition of these oxides (or mixing
of several oxides in one precipitate, i.e. one type of
oxide can be a “substrate” for the growth of oxide of
another composition). Moreover, this is typical for
oxides of various sizes.
XRD analysis was performed on the tapes of initial
and ODS HEAs after final annealing at T = 1273 K for
1 h. Corresponding diffraction patterns of the samples
are shown in Fig. 5.
90 ISSN 1562-6016. ВАНТ. 2021. №2(132)
Fig. 4. Distribution of elements in the matrix and precipitates of the ODS HEA Е32
Fig. 5. Diffraction patterns of studied alloys
According to XRD data all samples are single-phase
(within the sensitivity of the method) and consist of
FCC phase. Thus, for the initial alloys the lattice
parameters of the FCC phase are: a = (3.5943±3)∙10
-4
and a = (3.6038±3∙10
-4
)
Å, for E3 and E32, respectively.
For ODS HEAs Е3 and Е32 lattice parameters of FCC
phase are: a = (3.5932±3)∙10
-4
and a = (3.5994±3)∙10
-4
Å,
respectively. As can be seen, the lattice parameter of the
FCC phase in E32 alloy is greater than the value for the
E3 alloy (as well as for initial and ODS). This is due to
the replacement of cobalt in E32 alloys with iron, the
atomic radius of which is larger than that of cobalt. Also
it should be noted that the lattice parameters of the ODS
alloys are less than the corresponding values of the
initial alloys. This can be explained by the decrease in
the content of elements with a large atomic radius (Cr
ISSN 1562-6016. ВАНТ. 2021. №2(132) 91
and Mn) in the alloys matrix as a result of the formation
of complex oxides, which is consistent with the results
of the preliminary analysis (see Fig. 4). Diffraction
peaks of all alloys are narrow, which indicates the
coarse-grained structure of the samples (grain size is
more than 1 μm). The distribution of peaks intensities in
the diffraction patterns indicates the presence of texture
in the samples; moreover, the texture is significantly
different in the tapes of initial and ODS alloys. Thus, for
ODS alloys the intensity of peaks (220) is significantly
overestimated, i.e. in these alloys there is preferred
orientation of grains by crystallographic planes (220)
parallel to the sample surface. For the initial alloys the
intensity of peaks (200) and (311) is overestimated, i.e.
the texture is more complex in these samples.
Additional research is needed to determine the reasons
for this difference.
We also studied the mechanical properties of all
obtained high-entropy alloys. Typical stress-strain
diagrams of five-component high-entropy alloys E3 and
ODS E3 at different temperatures are shown in Fig. 6.
0.0 0.2 0.4 0.6
200
400
600
800
1000
800K
293K
77K
E3
E
n
g
in
e
e
ri
n
g
s
tr
e
s
s
,
M
P
a
Engineering strain
0.0 0.2 0.4
400
600
800
1000
1200
800K
293K
E
n
g
in
e
e
ri
n
g
s
tr
e
s
s
,
M
P
a
Engineering strain
77K
ODS E3
Fig. 6. Stress-strain diagrams of five-component high-entropy alloys E3 and ODS E3 at different temperatures
Determined values of yield strength (σ0.2), tensile
strength (σB) and uniform elongation to failure (δ) at
different temperatures are presented in Table 2. The
deformation curves of E3 and ODS E3 alloys show a
significant ability to deformation hardening
(especially alloy E3) and high ductility. The
maximum values of the yield strength, tensile
strength and elongation to failure for alloys E3 and
ODS E3 are observed at a temperature of 77 and
decrease as the test temperature increases. Exactly at
77 K deformation is accompanied not only by planar
slip of dislocations but also by nanoscale twinning,
which contributes to strain hardening and plasticity
increasing [16]. For the ODS E3 alloy the strain hardening
is noticeably lower, which indicates the effect of oxide
precipitates on the twinning process.
As can be seen after oxide dispersion strengthening
there is a significant increase in the yield strength by more
than 2 times for ODS E3 alloy. At the same time the
tensile strength increases slightly. As expected, oxide
dispersion strengthening leads to a significant decrease in
ductility, but it remains at a sufficient technological level
(up to 13% even at 800 K).
Table 2
Mechanical properties of E3 and ODS E3 HEAs at different temperatures
(σ0.2 – yield strength, σв – tensile strength, δ – elongation to failure)
Alloy
σ0.2, MPa σB, MPa δ, %
Test temperature
77 К 293 К 800 К 77 К 293 К 800 К 77 К 293 К 800 К
Е3 437 221 166 1150 565 478 71 41.5 29
ODS Е3 664 576 358 1289 789 493 54 33 13
Stress-strain diagrams of non-cobalt high-entropy
alloys E32 and ODS E32 at different temperatures are
shown in Fig. 6. Determined values of yield strength
(σ0.2), tensile strength (σB) and uniform elongation to
failure (δ) at different temperatures are presented in
Table 3. The deformation curves of E32 and ODS
E32 alloys at 77 K also show a significant
deformation hardening and high ductility. Probably,
as in the E3 alloy nanoscale twinning contributes to
the deformation hardening and ductility increasing.
The yield strength for alloy E32 at 77 K was
lower by 12% than that in alloy E3. Under equal
conditions this reduction can be attributed to the solid-
solution hardening. After oxide dispersion strengthening
significant increase in the yield strength at 293 and 973 K
is observed for the alloy ODS E32 (almost 2.5 times).
There was also a noticeable increase in tensile strength
(1.5 times). Similar to the ODS E3 alloy the ductility of
the non-cobalt ODS E32 decreased at the maximum test
temperature (973 K) down to 12%. Thus, mechanical
properties of the non-cobalt ODS E32 and the five-
component ODS E3 alloys are quite close, which allows to
prefer the first one, because Co has high induced activity
after irradiation.
92 ISSN 1562-6016. ВАНТ. 2021. №2(132)
0.0 0.2 0.4 0.6
200
400
600
800
1000
E32
973K
293K
E
n
g
in
e
e
ri
n
g
s
tr
e
s
s
,
M
P
a
Engineering strain
77K
0.0 0.1 0.2
400
600
800
ODS E32
973K
293K
E
n
g
in
e
e
ri
n
g
s
tr
e
s
s
,
M
P
a
Engineering strain
Fig. 7. Stress-strain diagrams of high-entropy alloys E32 and ODS E32 at different temperatures
Table 3
Mechanical properties of E32 and ODS E32 HEAs at different temperatures
Alloy
σ0.2, MPa σB, MPa δ, %
Test temperature
77 К 293 К 973 К 77 К 293 К 973 К 77 К 293 К 973 К
Е32 388 187 135 1137 602 241 72.5 44 31
ODS Е32 520 325 842 387 24.5 12
Different patterns of the surface fracture were
obtained after tensile tests of HEAs depending on the
composition and microstructure of the alloys.
Corresponding fractograms of the fractured samples
after tensile tests at temperature of 293 K are shown in
Fig. 8.
a
Е3 Е32
b
ODS Е3 ODS Е32
wt.% at.%
O K 12.10 32.23
Cr K 22.52 18.45
Mn K 20.21 15.67
Fe K 30.36 23.16
Ni K 13.80 10.02
Y L 0.26 0.12
Zr K 0.75 0.35
c
Fig. 8. Fractograms of HEAs tapes after mechanical tests at 293 K
ISSN 1562-6016. ВАНТ. 2021. №2(132) 93
Analyzing the difference in the structure of the
fracture surfaces, it can be noted that presence of oxide
precipitates of micron size (see Fig. 8,a) plays
significant role in the initial alloys. Such precipitates are
almost always present in these alloys [16], but,
according to the authors, do not significantly affect their
mechanical characteristics. These precipitates, observed
in the middle of the pits, play a significant role in
initiating the material fracture processes. In E32 alloy
there are fewer such precipitates but their size is larger
than that in E3 alloy (see Fig. 8,a). Therefore, the nature
of the fracture surface in these alloys is considerably
different. For HEAs E3 and especially E32 in the initial
state on the fracture surface next to the microrelief of
the pit structure there are surfaces of smooth
delamination, which are smooth, structureless surface
areas with waved elements. The formation of such
surfaces is associated with intense preliminary plastic
deformation and faster crack propagation in comparison
with pit fracture.
The fracture surfaces of ODS HEAs E3 and E32 (see
Fig. 8,b) show pit character and indicate a high density
of oxide precipitates of submicron size, on which pits
are formed. Exactly the high density of such precipitates
determines the refinement of the pit relief. A large
number of small pits on the fracture surface, which are
observe for both ODS HEAs E3 and E32, corresponds
to a high degree of oxide strengthening. Small but
sufficiently deep pits indicate a combination of high
strength and toughness; the uniformity of the pit relief
indicates a uniform distribution of submicron oxide
particles.
As can be seen the fracture in the studied ODS
alloys takes place mainly on the surface of the “particle-
matrix”, which indicates a reduced level of cohesion of
the particles with the matrix. Therefore, separate
particles are often observed in the pits on the fracture
surface. Analysis of these particles, performed in point
mode, showed that the chemical composition of the
particles differs from the matrix and corresponds to
complex oxides (see Fig. 8,c). Moreover, as previously
assumed, just Cr and Mn atoms with large atomic radii
included in the composition of the oxides, which could
affect the decrease in the lattice parameter of the matrix
phase.
CONCLUSIONS
Oxide dispersion-strengthened HEAs CoCrFeMnNi
and CrFe2MnNi were obtained by mechanical alloying.
The size spectrum of oxide precipitates for studied
alloys is characterized by the presence of both small
precipitates ~ 10 nm, which are characteristic for ODS
steels, and larger particles (50…150 nm). The density of
oxide precipitates is near ~ 10
21
m
-3
.
The composition of the oxides includes not only Y
and Zr, but also the matrix elements of the alloys,
mainly Cr and Mn.
Studies of the mechanical properties of the obtained
ODS HEAs showed that the yield stress of those alloys
increased by 2 times compared to the initial state, the
ultimate strength practically did not change, and
plasticity at 293 K was about 20…30%.
A similar character of the microstructure and close
values of mechanical characteristics make it possible to
prefer non-cobalt ODS E32 HEA as a possible
candidate for nuclear energy applications.
ACKNOWLEDGEMENTS
This work was prepared within the project
№ 2020.02/0327 “Fundamental aspects of the new
materials creation with unique physical, mechanical and
radiation properties based on the concentrated
multicomponent alloys”, implemented with the financial
support of the National Research Foundation of
Ukraine.
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Статья поступила в редакцию 12.03.2021 г.
МИКРОСТРУКТУРА И МЕХАНИЧЕСКИЕ СВОЙСТВА ДИСПЕРСНО-УПРОЧНЕННЫХ
ОКСИДАМИ ВЫСОКОЭНТРОПИЙНЫХ СПЛАВОВ CoCrFeMnNi И CrFe2MnNi
И.В. Колодий, А.Н. Великодный, М.А. Тихоновский, В.Н. Воеводин, А.С. Кальченко,
Р.Л. Василенко, В.С. Оковит
Методом механического легирования с последующим компактированием и спеканием получены
высокоэнтропийные сплавы CoCrFeMnNi и CrFe2MnNi, дисперсно-упрочненные предварительно синтезированными
нанооксидами состава 80%Y2O3+20%ZrO2 (мол.%). Средний размер зерен в дисперсно-упрочненных сплавах составил
примерно 2 мкм. Оксидные выделения в сплавах характеризуются наличием мелких частиц со средним размером около
10 нм и плотностью ≈ 1021 м-3, а также незначительного количества больших частиц с размерами 50…150 нм.
Установлен качественный состав частиц разного размера. Исследованы механические свойства сплавов при разных
температурах. Показано, что прочностные характеристики значительно повышаются при упрочнении сплавов
нанооксидными частицами.
МІКРОСТРУКТУРА ТА МЕХАНІЧНІ ВЛАСТИВОСТІ ДИСПЕРСНО-ЗМІЦНЕНИХ
ОКСИДАМИ ВИСОКОЕНТРОПІЙНИХ СПЛАВІВ CoCrFeMnNi І CrFe2MnNi
І.В. Колодій, О.М. Великодний, М.А. Тихоновський, В.М. Воєводін, О.С. Кальченко,
Р.Л. Василенко, В.С. Оковіт
Методом механічного легування з наступним компактуванням та спіканням отримано високоентропійні сплави
CoCrFeMnNi та CrFe2MnNi, що зміцнені попередньо синтезованими нанооксидами складу 80%Y2O3+20%ZrO2 (% мол).
Середній розмір зерен у дисперсно-зміцнених сплавах близько 2 мкм. Оксидні виділення в сплавах характеризуються
присутністю дрібних часток з середнім розміром близько 10 нм і щільністю ≈ 1021 м-3, а також незначної кількості
більших часток з розмірами 50…150 нм. Встановлено якісний склад часток різного розміру. Досліджені механічні
властивості сплавів при різних температурах. Показано, що міцнісні характеристики суттєво підвищуються при
зміцненні сплавів нанооксидними частками.
|
| id | nasplib_isofts_kiev_ua-123456789-194897 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T16:16:25Z |
| publishDate | 2021 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Kolodiy, I.V. Velikodnyi, O.M. Tikhonovsky, M.A. 2023-12-01T13:18:55Z 2023-12-01T13:18:55Z 2021 Microstructure and mechanical properties of oxide dispersion strengthened high-entropy alloys CoCrFeMnNi and CrFe₂MnNi / I.V. Kolodiy, O.M. Velikodnyi, M.A. Tikhonovsky, V.N. Voyevodin, O.S. Kalchenko, R.L. Vasilenko, V.S. Okovit // Problems of Atomic Science and Technology. — 2021. — № 2. — С. 87-94. — Бібліогр.: 26 назв. — англ. 1562-6016 DOI: https://doi.org/10.46813/2021-132-087 https://nasplib.isofts.kiev.ua/handle/123456789/194897 620.187:621.039.53 High-entropy alloys (HEAs) CoCrFeMnNi and CrFe₂MnNi, dispersion-strengthened by pre-synthesized nanooxides composition of 80%Y₂O₃+20%ZrO₂ (mol.%) were obtained by mechanical alloying followed by compaction and sintering. Average grain size of the oxide dispersion-strengthened (ODS) alloys was about 2 μm. Oxide precipitates in alloys are characterized by the presence of small particles with an average size of about 10 nm and a density of ≈ 10²¹ m⁻³, as well as small amount of larger particles sizes of 50…150 nm. The qualitative composition of particles of different sizes has been established. Mechanical properties of HEAs were studied at different temperatures. It is shown that strengthening of the studied alloys by nanooxide particles leads to a significant increase in strength characteristics. Методом механічного легування з наступним компактуванням та спіканням отримано високоентропійні сплави CoCrFeMnNi та CrFe₂MnNi, що зміцнені попередньо синтезованими нанооксидами складу 80%Y₂O₃+20%ZrO₂ (mol.%). Середній розмір зерен у дисперсно-зміцнених сплавах близько 2 мкм. Оксидні виділення в сплавах характеризуються присутністю дрібних часток з середнім розміром близько 10 нм і щільністю ≈ 10²¹ м⁻³, а також незначної кількості більших часток з розмірами 50…150 нм. Встановлено якісний склад часток різного розміру. Досліджені механічні властивості сплавів при різних температурах. Показано, що міцнісні характеристики суттєво підвищуються при зміцненні сплавів нанооксидними частками. Методом механического легирования с последующим компактированием и спеканием получены высокоэнтропийные сплавы CoCrFeMnNi и CrFe₂MnNi, дисперсно-упрочненные предварительно синтезированными нанооксидами состава 80%Y₂O₃+20%ZrO₂ (mol.%). Средний размер зерен в дисперсно-упрочненных сплавах составил примерно 2 мкм. Оксидные выделения в сплавах характеризуются наличием мелких частиц со средним размером около 10 нм и плотностью ≈ 10²¹ м⁻³, а также незначительного количества больших частиц с размерами 50…150 нм. Установлен качественный состав частиц разного размера. Исследованы механические свойства сплавов при разных температурах. Показано, что прочностные характеристики значительно повышаются при упрочнении сплавов нанооксидными частицами. This work was prepared within the project № 2020.02/0327 “Fundamental aspects of the new materials creation with unique physical, mechanical and radiation properties based on the concentrated multicomponent alloys”, implemented with the financial support of the National Research Foundation of Ukraine. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Thermal and fast reactor materials Microstructure and mechanical properties of oxide dispersion strengthened high-entropy alloys CoCrFeMnNi and CrFe₂MnNi Мікроструктура та механічні властивості дисперсно-зміцнених оксидами високоентропійних сплавів CoCrFeMnNi і CrFe₂MnNi Микроструктура и механические свойства дисперсно-упрочненных оксидами высокоэнтропийных сплавов CoCrFeMnNi и CrFe₂MnNi Article published earlier |
| spellingShingle | Microstructure and mechanical properties of oxide dispersion strengthened high-entropy alloys CoCrFeMnNi and CrFe₂MnNi Kolodiy, I.V. Velikodnyi, O.M. Tikhonovsky, M.A. Thermal and fast reactor materials |
| title | Microstructure and mechanical properties of oxide dispersion strengthened high-entropy alloys CoCrFeMnNi and CrFe₂MnNi |
| title_alt | Мікроструктура та механічні властивості дисперсно-зміцнених оксидами високоентропійних сплавів CoCrFeMnNi і CrFe₂MnNi Микроструктура и механические свойства дисперсно-упрочненных оксидами высокоэнтропийных сплавов CoCrFeMnNi и CrFe₂MnNi |
| title_full | Microstructure and mechanical properties of oxide dispersion strengthened high-entropy alloys CoCrFeMnNi and CrFe₂MnNi |
| title_fullStr | Microstructure and mechanical properties of oxide dispersion strengthened high-entropy alloys CoCrFeMnNi and CrFe₂MnNi |
| title_full_unstemmed | Microstructure and mechanical properties of oxide dispersion strengthened high-entropy alloys CoCrFeMnNi and CrFe₂MnNi |
| title_short | Microstructure and mechanical properties of oxide dispersion strengthened high-entropy alloys CoCrFeMnNi and CrFe₂MnNi |
| title_sort | microstructure and mechanical properties of oxide dispersion strengthened high-entropy alloys cocrfemnni and crfe₂mnni |
| topic | Thermal and fast reactor materials |
| topic_facet | Thermal and fast reactor materials |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/194897 |
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