ISSN 1562-6016. ВАНТ. 2022. №1(137)








111
https://doi.org/10.46813/2022-137-111

SYNTHESIS OF THE Ti-Zr-Ni ALLOYS BY
THE “HYDRIDE CYCLE” METHOD

O.E. Dmytrenko
1
, I.V. Kolodiy
1
, T.B. Yanko
2
, V.M. Borysenko
1
, K. Irwin
3
, R.L. Vasilenko
1

1
National Science Center “Kharkov Institute of Physics and Technology”, Kharkiv, Ukraine;
2
PJCS “Titanium Institute”, Zaporizhzhya, Ukraine;
3
Quantum Gravity Research, Los Angeles, CA, USA
E-mail: dmitrenko@kipt.kharkov.ua

A comprehensive study of the technical parameters and conditions for the synthesis of ternary alloys in the Ti-
Zr-Ni system by the “hydride cycle” method was carried out. The influence on the synthesis process of such
parameters as: temperature and annealing time, heating rate, cooling conditions, material composition, dispersion,
hydrogen content in the hydrides used, the presence of impurities, mixing and pressing methods, and the degree of
pressing of the starting components was determined. The alloys of the following compositions were synthesized and
investigated: Ti40.5Zr31.9Ni27.6, Ti41.5Zr41.5Ni17, Ti40Zr40Ni20, Ti44Zr40Ni16. The optimal technological parameters and
conditions for the synthesis of ternary alloys are determined. It has been established that the key factors in the
process of compound formation during hydride dissociation are the dispersion and homogeneity of the initial
compacted components. It was found that the synthesis of ternary alloys in the Ti-Zr-Ni system occurs during a
short-term exothermic reaction in the “thermal explosion” mode, which begins in the temperature region
corresponding to the α↔β polymorphic transformation of zirconium and titanium.
PACS: 81.20.-n, 81.40.-z, 71.20.Lp

INTRODUCTION

Most zirconium alloys, including quasicrystalline
(QC) materials and intermetallic compounds based on
the Laves phase C14 L-TiZrNi, are capable of
reversibly absorbing a significant amount of hydrogen
and are promising materials for hydrogen energy.
However, the production of these materials, due to the
high melting point and chemical activity of the starting
components, is a complex and energy-intensive task.
Traditional methods for producing metal alloys, in this
case, are significantly limited. It is necessary to use
sophisticated vacuum equipment, which allows for non-
crucible melting since molten titanium and zirconium
actively interact with crucible materials. In this case,
saturation with interstitial impurities also occurs,
primarily with oxygen and nitrogen, which prevents the
formation of a given structure due to the precipitation of
phases stabilized by dissolved gas impurities [1–4].
Thus, the main methods for producing bulk Ti-Zr-Ni
alloys are vacuum-arc and electron-beam melting. If it
is necessary to obtain a QC material, additional heat
treatment is required – quick quenching (melt spinning)
[5] or long-term annealing, which allows one to finally
obtain QC samples. Synthesizing large volumes of
homogeneous samples in this way is technically
difficult and expensive, which in turn limits further
practical application.
The technology of the “hydride cycle” is based on
the interaction of the products of thermal dissociation of
hydrides of the starting components with the formation
of systems and phases characteristic of these materials
with significantly lower energy consumption. As shown
in [6–12], this technique is successfully used for the
synthesis of various binary and ternary alloys of
refractory metals of the zirconium group. Including
complex intermetallic compounds of the Ti-Zr-Ni
system. Thus, the possibility of synthesizing stable
Ti-Zr-Ni quasicrystals was shown in [6]. For the
successful synthesis of Ti-Zr-Ni system alloys with the
given structural characteristics using this technology, it
is necessary to establish a number of technological
parameters. The main influencing factors are:
1. Heat treatment parameters: annealing temperature,
annealing time, heating rate, pressure during annealing,
cooling conditions.
2. The parameters of the starting components:
material composition, dispersion, hydrogen content in
the hydrides used, the presence of impurities.
3. Compaction parameters: method of mixing the
starting components, method of compaction/pressing,
degree of compression.
The aim of this work is to determine the optimal
parameters and conditions for the synthesis of QC
materials and intermetallic alloys of the Ti-Zr-Ni
system.

1. MATERIALS AND METHODS

To conduct a study on the synthesis of QC materials
and intermetallic alloys of the Ti-Zr-Ni system, samples
of the following starting compositions (in at.%) have
been prepared:
1) Ti40.5Zr31.9Ni27.6 – this composition have been
shown to strongly interact with H2 gas [4];
2) Ti41.5Zr41.5Ni17 – composition with experimentally
confirmed formation of quasicrystals during melt
spinning [5];
3) Ti40Zr40Ni20 – theoretically calculated optimal
composition for the formation of the QC phase [13];
4) Ti44Zr40Ni16 – corresponds to the quasicrystals
obtained by the technology of the “hydride cycle” [10].
Initial studies were carried out on samples of the
composition Ti40.5Zr31.9Ni27.6. As the ranges, modes and
indicators were refined, the study of samples of
composition Ti41.5Zr41.5Ni17 and then Ti40Zr40Ni20/
Ti44Zr40Ni16 began. The following powders were used

112

ISSN 1562-6016. ВАНТ. 2022. №1(137)
for all compositions under investigation: Ti – titanium
powder Grade 1; TiH2 – titanium hydride powder (from
TG-90, hydrogen content 3.6 wt.%); Zr – zirconium
powder PCRK-1; ZrH2 – zirconium hydride powder
(from PCRK-1, hydrogen content 2.0 wt.%); Ni  nickel
powder
electrolytic PNE-1; Ni – nickel
powder
carbonyl PNC. The powders were mixed by three
different methods:
a) “drunk barrel” mixer for 60…120 min at the
rotational speed of ~ 30…40 rpm;
b) hand rubbing/mixing in alundum mortar;
c) high-energy grinding/mixing in a ball mill.
The obtained mixture of powders was compacted
with the different degree of pressing: from 3 to 80 t in
the briquettes Ø 15…30 mm in diameter and height
6…25 mm. Heat treatment in hydrogen (in the “thermal
explosion” mode) was carried out by: heating to 450 °C
in vacuum, hydrogen supply, holding for 1.5 h in a
hydrogen atmosphere
(2…5 atm) at a constant
temperature of 450 °C. Cooling to room temperature
under a hydrogen atmosphere for 2 h. Annealing of all
samples was carried out in a vacuum (1...5)∙10
-3
Pa at
700…950 °C.
The structure and composition of the samples were
studied by SEM and EDX microanalysis, using
scanning electron microscope JSM 7001F with an
accelerating voltage of 20 kV. Observation of the
structure was carried out both in the secondary electron
(SEI) mode and in the backscattered electron (COMPO)
mode forming the composite image contrast. The
composition was analyzed using the INCA PentaFET*3
detector and the Oxford Instruments INCA 4.11
program. To calibrate the quantitative analysis, a
standard of cobalt with a purity of 99.99% was used.
The mapping mode is used to determine the degree of
distribution of elements over the sample. XRD studies
of the sample were carried out using DRON-4-07 X-ray
diffractometer
in Cu-Kα
radiation. The
initial
components of the samples, as well as samples of Ti-Zr-
Ni alloys after heat treatment in hydrogen (in the
“thermal explosion” mode)/vacuum annealing, were
investigated for desorption under vacuum heating in the
temperature range 0...900 °C in a mass-spectrometer
MX7203. The MX7203 mass-spectrometer is designed
to determine the hydrogen present in alloys and the
composition of the gas phase released from the material
when heated in a vacuum.

2. RESULT AND DISCUSSION
2.1. HEAT TREATMENT
The key to the hydride cycle technology is heat
treatment. Accordingly, the most significant parameter
is temperature, heating and cooling rate, and also
annealing time. Therefore, it is advisable to initially
determine the effect of temperature and annealing time
on the final structure of the synthesized samples and
establish optimal conditions for the formation of a given
structure. To determine
the optimal
annealing
temperature of
samples
for
the
synthesis of
quasicrystals, the temperature ranges of hydrogen
desorption from the used starting components and their
mixtures were determined (Fig. 1). This made it
possible to determine the upper and lower boundaries of
the dissociation of hydrides and, accordingly, to
establish the annealing temperature of the samples.
From the literature data [14–17] it is known that
hydrogen is able to saturate titanium to a limiting
stoichiometric
concentration
of
4.04 wt.%,
and
zirconium above 2 wt.%, this is accompanied by
significant changes in the properties of the material. The
H2 content in the starting hydrides affects the properties
of the resulting binary and ternary alloys (porosity,
phase composition). This is due to the fact that during
the dissociation of hydrides during heating in vacuum,
TiH2 and ZrH2 produce hydrogen, and a decrease in the
concentration of hydrogen in their crystal lattices leads
to a sequence of phase transformations: ZrH2 (ε) →
ZrH2 (δ) → Zr (β) → Zr (α) and TiH2 (ε) → TiH2 (δ) →
Ti (β) → Ti (α). During dehydrogenation, both materials
undergo
a
chain
of
phase
transformations
MeH2 → β (bcc) → α (hcp)
[10].
However,
the
temperature ranges of phase transformations in the
process of dehydrogenation
for
zirconium are
150…200 °C higher than for titanium (see Fig. 1).

Fig. 1. Thermal desorption TiH2; ZrH2;
(TiH2)40.5Zr31.9Ni27.6 + H2; Ti40.5Zr31.9Ni27.6 + H2

In addition, it is necessary to take into account the
allotropic (phase) transitions of each of the components
of the sample, since they can affect the structure already
formed during annealing. It is known that titanium
exists in two crystalline modifications: hcp α-Ti and
bcc β-Ti
(transition
temperature α ↔ β = 883 °C).
Similarly,
zirconium also has
two
crystalline
modifications: hcp α-Zr and bcc β-Zr (transition
temperature
α ↔ β = 863 °C). Therefore,
if
the
annealing temperature is higher than these values, then
upon cooling of the sample, structural changes are
possible due to polymorphic transformation. This will
happen if Ti and Zr formed during “reductive”
annealing did not fully interact with each other and with
Ni. Residues of β-Ti and β-Zr, undergoing polymorphic
transformation during cooling of the sample, can lead to
a change in the structure of the formed triple alloy
(quasicrystal). Therefore, the annealing time should be
selected so that the reaction between the components is
complete and a triple alloy is formed in the entire
volume of the sample. This, in turn, is determined by
diffusion processes (and, accordingly, the annealing
temperature) and can be established empirically.
It should be remembered that according to the
literature [1, 2, 18, 19], the icosahedral quasicrystals of
0
10
20
30
40
50
60
70
80
90
100
0
100
200
300
400
500
600
700
800
Temperature, °С
Pressure, mm.Hg.Sample 3: Ti30Zr45Ni25 + H2
Sample 2:(TiH2)30Zr45Ni25 + H2
ZrH2
TiH2
Pressure, mm Hg

ISSN 1562-6016. ВАНТ. 2022. №1(137)








113
the Ti-Zr-Ni system are stable at temperatures below
700 °C; when heated above, the QC phase is converted
to the Laves phase mixture L-TiZrNi, α-(Ti, Zr) and
phases (Ti, Zr)2Ni. Therefore, the lower the sintering
temperature, the greater the probability of maintaining
the QC phase. In this case, the sintering regime should
ensure that the process of the formation of the ternary
alloy proceeds according to the solid-phase diffusion
mechanism in full.
Thus, to choose the optimal annealing mode means
to determine the heat treatment conditions under which:
– there was a complete dissociation of the starting
hydrides;
– hydrogen is removed as much as possible from the
material;
– hydride
dissociation
products
completely
interacted with each other and with the other
components of the sample;
– formed a structural phase state characteristic of
this composition;
– the processes of high-temperature evolution of the
material
are
limited
(aging,
polymorphic
transformations, precipitation of secondary phases,
diffusion segregation, etc.).
From the graphs of thermal desorption shown in
Fig. 1, it can be seen that the active evolution of
hydrogen from TiH2 begins at 400 °C and practically
ends above 650 °C with a maximum at 570 °C. ZrH2
decomposition occurs in a wider temperature range of
300...700 °C and has a two-stage character with peaks at
430 and 650 °C. The graphs of thermal desorption from
powder samples No. 2, 3 are similar and have several
maxima, which represent the superposition of the
decomposition processes of TiH2 and ZrH2, which is
clearly visible on the general graph. Thus, it can be
concluded that the main evolution of hydrogen from
hydrides ends at 700 °С; however, it is necessary to take
into account that a certain amount of hydrogen is stored
in Ti and Zr above 1000 °С [17]. Since the composition
of Ti40.5Zr31.9Ni27.6 samples is eutectic, the upper limit of
the annealing temperatures will be in the region of the
eutectic formation. According to the double state
diagrams for Ti-Ni and Zr-Ni, the minimum eutectic
temperature is 942 and 960 °С, respectively. Thus, the
temperature range for research is 700…950 °C.
2.2. ANNEALING TEMPERATURE
Initial
studies
were
carried
out
on
(TiH2)40.5Zr31.9Ni27.6 and Ti40.5Zr31.9Ni27.6 samples treated
in hydrogen in the “thermal explosion” mode followed
by vacuum annealing at different temperatures. The
XRD results of a series of samples of No. 1 after
annealing at different temperatures showed that the
minimum temperature required for the interaction of the
starting components and the formation of ternary phases
is 910 °C (with an annealing time of 1 h). Previous
experiments showed that the upper temperature is
limited to 950 °C, above which eutectic fusion of Ti and
Zr with Ni occurs. Thus, the optimum temperature for
sintering Ti-Zr-Ni samples with electrolytic nickel using
the “hydride cycle” technology is 920...930 °С. Electron
microscopy of the (TiH2)40.5Zr31.9Ni27.6 sample before
and after heat treatment at different temperatures is
presented in the COMPO mode in Fig. 2. It should be
noted that in the No.1c diffraction pattern there are lines
that can be attributed to the QC phase (at angles
diffraction 2θ = 36.5° and 38.5°). But due to the weak
intensity of the quasicrystal lines in the diffractogram, it
is impossible to select a 5th order line to unambiguously
confirm the QC phase in the sample. X-ray diffraction
patterns of the samples are presented in Fig. 3. The
results of the phase composition are summarized in
Table 1.
The low nickel content in the starting powders is due
to the uneven distribution of the starting components
during transportation, due to a significant difference in
the dispersion of the starting TiH2, Zr (up to 10 μm) and
electrolytic Ni (up to 100 μm) (see Fig. 2,a). The
mismatch of the initial composition during the XRD
study does not affect the final composition of the
synthesized sample, since, during the preparation of the
samples, the mixing of the starting components occurs
immediately before pressing. And the powder mixture is
not compacted during transportation and the associated
uneven distribution of components of different
dispersion. However, the discovered phenomenon led to
the study of the effect of the degree of dispersion of the
components and mixing methods on the synthesis of the
Ti-Zr-Ni ternary alloy and the formation of the
structure.


a



b



c

Fig. 2. Electron microscopy of the sample (TiH2)40.5Zr31.9Ni27.6 + H2 before and after heat treatment:
a – powder sample No. 1a; b – sample No. 1c after annealing at 700 °C for 1 h + 910 °C for 1 h;
c – sample No. 1d after annealing at 920 °C for 1 h




114

ISSN 1562-6016. ВАНТ. 2022. №1(137)
Table 1
Phase composition of the studied samples Ti40.5Zr31.9Ni27.6

Sample
Heat
treatment
mode
Phase
Weight content,
wt.%
Lattice parameters, Å
No. 1a (TiH2)40.5Zr31.9Ni27.6,
TiH2, Zr, PNE-1
powder + H2
TiH2
28.6
a = 4.452
ZrH2-ε
62.9
a = 3.515; c = 4.475
Ni
8.5
a = 3.524
No. 1b (TiH2)40.5Zr31.9Ni27.6,
TiH2, Zr, PNE-1
910 °С, 1 h
Ti-α
19.9
a = 2.962; c = 4.740
Zr-α
45.2
a = 3.245; c = 5.169
Ni
5.2
a = 3.526
ZrH2-δ
24.1
a = 4.780
NiTiO3
5.6
a = 5.469; α = 55.37°
No. 1c (TiH2)40.5Zr31.9Ni27.6,
TiH2, Zr, PNE-1
700 °С, 1 h +
910 °С, 1 h
Ni
–
a = 3.524
Zr-α
–
a = 3.232; c = 5.147
(Ti,Zr)2Ni
–
a = 11.899
QC-?
–
–
No. 1d (TiH2)40.5Zr31.9Ni27.6,
TiH2, Zr, PNE-1
920 °С, 1 h
(Ti,Zr)2Ni
74.2
a = 11.813
L-TiZrNi
25.8
a = 5.222; c = 8.537
No. 1e Ti40,5Zr31,9Ni27,6,
Ti, Zr, PNE-1
powder + H2
TiH2
30.6
a = 4.453
ZrH2-ε
55.2
a = 3.518; c = 4.462
Ni
14.2
a = 3.524
No. 1f Ti40.5Zr31.9Ni27.6,
Ti, Zr, PNE-1
920 °С, 1 h
(Ti,Zr)2Ni
93.6
a = 11.820
L-TiZrNi
6.4
a = 5.218; c = 8.545
No. 1g Ti40.5Zr31.9Ni27.6,
Ti, Zr, PNE-1
930 °С, 1 h
(Ti,Zr)2Ni
79.6
a = 11.864
L-TiZrNi
20.4
a = 5.223; c = 8.556
No. 1h Ti40.5Zr31.9Ni27.6,
Ti, Zr, PNE-1
940 °С, 1 h
(Ti,Zr)2Ni
92.1
a = 11.845
L-TiZrNi
7.9
a = 5.232; c = 8.558
No. 1j
(TiH2)40.5(ZrH2)31.9Ni27.6,
TiH2, ZrH2, PNE-1
920…930 °С,
1 h
(Ti,Zr)2Ni
72.8
a = 11.791



Fig. 3. X-ray diffraction patterns of samples (TiH2)40.5Zr31.9Ni27.6: a – powder sample No. 1a; b – sample No. 1c after
annealing at 700 °C for 1 h + 910 °C for 1 h; c – sample No. 1d after annealing at 920 °C for 1 h

2.3. DISPERSION OF INITIAL COMPONENTS
Fine samples of TiH2, ZrH2, Zr with a size of
(0.1...10 μm) and two types of nickel powder were used
to prepare the samples. The first is electrolytic nickel of
the PNE-1 brand, which was sieved through a series of
sieves, for separation into fractions, the fine and coarse
fractions were used separately (less than 40 and more
than 100 μm, respectively). The second is carbonyl
nickel with a particle size of 0.1...10 μm. Studies have
shown that the difference in the dispersion of Ti, Zr, Ni
leads to local inhomogeneities, which give a significant
deviation from a given composition in small areas of the
analysis. Therefore, it is necessary to use the initial
components of the same dispersion and minimum size.
This will allow to achieve uniform distribution of
elements along the sample, increase contact zones and
accelerate the process of formation of a triple alloy.
Thus, the use of finely dispersed nickel made it possible
a
b
c

ISSN 1562-6016. ВАНТ. 2022. №1(137)








115
to achieve greater phase homogeneity of the samples
and to lower the sintering temperature of the samples
with the formation of the alloy by 50 °C.
Further studies were conducted on samples of a
different composition. According to published data [5],
the
composition
of Ti41.5Zr41.5Ni17
is
optimal
(experimentally confirmed) for the synthesis of stable
quasicrystals in the Ti-Zr-Ni system. In addition, ZrН2
powder (instead of zirconium powder) and the sieved
fine fraction of nickel PNE-1 (less than 40 μm in size)
were used as starting components. X-ray diffraction
patterns of the samples are presented in Fig. 4, the
results of the phase composition are summarized in
Table 2. Electron microscopy of the cleavage of the
(TiH2)41.5(ZrН2)41.5Ni17 sample after annealing at 930 °C
for 1 h is presented in Fig. 5.


Fig. 4. X-ray diffraction patterns of samples (TiH2)40Zr40Ni20: No. 4a, 4b, 4c


Fig. 5. Electron microscopy samples (TiH2)41.5(ZrН2)41.5Ni17 after annealing at 930 °С, for 1 h

As can be seen from the XRD analysis data
presented in Table 2, the use of a finely divided fraction
of electrolytic nickel (samples No. 2a-2d) led to a
noticeable decrease in the temperature of the solid phase
sintering. However, a change in the composition to the
optimal one for the synthesis of the QC phase did not
affect the phase composition of the samples. X-ray
diffraction analysis confirmed only the presence of
crystalline phases: L-TiZrNi, (Ti,Zr)2Ni and α-(Ti,Zr).
In sample 2c, a halo is present in the diffraction pattern
in the range of angles 2θ ≈ 30…42°, which indicates the
presence of an X-ray amorphous phase in the sample.
No hydrides were detected in the sample, i.e., hydrogen
left the sample, but this temperature is not enough for
synthesis. Also on this diffraction pattern, there are lines
that can be interpreted as a quasicrystal, but the
presence of a halo prevents unambiguous identification.
Therefore, the presence of a QC phase is not given.
2.4. HYDROGEN CONTENT IN THE HYDRIDES
The use of TiH2 as initial components with different
hydrogen contents (2...3.6 wt.%) did not affect the
structural phase composition of the final samples. As
well as the combined use of TiH2 and ZrH2 (series
No. 2). Regardless of the weight content of hydrogen in
hydrides (or one/both hydrides are present in the
mixture), a similar alloy structure is formed after
annealing in a vacuum. The amount of hydrogen in the
initial hydrides significantly affects the time it takes to
reach the heat treatment mode. The more hydrogen in
the initial charge, the longer the dehydrogenation
process before sintering the sample.
2.5. DURATION OF ANNEALING
Experiments were carried out to study the effect of
the duration of isothermal annealing in a vacuum on the
structural phase state of the obtained samples. The
duration of annealing ranged from 2 to 15 h at a
temperature of 800 °C. From the data given in Table 2
(No. 4a, 4d, and 6a, respectively), it follows that this
temperature is not sufficient for the synthesis of a
ternary alloy, regardless of the annealing duration. After
prolonged annealing in vacuum, the samples are a
mixture of Ti, Zr, Ni with a small amount of (Ti,Zr)2Ni.

116

ISSN 1562-6016. ВАНТ. 2022. №1(137)
Table 2
Phase composition of samples Ti41.5Zr41.5Ni17/Ti40Zr40Ni20/Ti44Zr40Ni16
under various synthesis conditions

Sample
Heat treatment
mode
Phase
Weight content,
wt,%
Lattice parameters, Å
No. 2a
(TiH2)41.5(ZrН2)41.5Ni17,
TiH2, ZrH2, fine PNE-1
930 °С, 1 h
(Ti,Zr)2Ni
89.9
a = 11.965
L-TiZrNi
10.1
a = 5.226; c = 8.622
No. 2b
(TiH2)41.5(ZrН2)41.5Ni17,
TiH2, ZrH2, fine PNE-1
920 °С, 1 h
(Ti,Zr)2Ni
70.8
a = 12.004
L-TiZrNi
8.8
a = 5.238; c = 8.675
(Ti,Zr)-α
20.4
a = 3.076; c = 4.918
No. 2c
(TiH2)41.5(ZrН2)41.5Ni17,
TiH2, ZrH2, fine PNE-1
850 °С, 1 h
Ni
–
a = 3.521
Zr-α
–
a = 3.232; c = 5.148
Ti-α
–
a = 2.951; c = 4.686
No. 2d
(TiH2)41.5(ZrН2)41.5Ni17,
TiH2, ZrH2, fine PNE-1
870 °С, 1.5 h
(Ti,Zr)2Ni
84.1
a = 11.970
L-TiZrNi
2.9
a = 5.231; c = 8.578
(Ti,Zr)-α
13.0
a = 3.064; c = 4.910
No 3a (TiH2)40Zr40Ni20,
TiH2, Zr, carbonyl Ni,
mechanical activation
910…915 °С,
2 h 10 min
(Ti,Zr)2Ni
62.4
a = 11.970
L-TiZrNi
32.3
a = 5.233; c = 8.568
(Ti,Zr)-α
5.3
a = 3.088; c = 4.898
No. 3b (TiH2)44Zr40Ni16,
TiH2, Zr, carbonyl Ni,
mechanical activation
910…915 °С,
2 h 10 min
(Ti,Zr)2Ni
52.7
a = 11.974
L-TiZrNi
26.3
a = 5.240; c = 8.560
(Ti,Zr)-α
21.0
a = 3.073; c = 4.896
No. 4a (TiH2)40Zr40Ni20,
TiH2, Zr, carbonyl Ni,
mechanical activation
800 °С, 2 h
Ti-α
~ 60
a = 2.975; c = 4.698
Zr-α
~ 27
a = 3.238; c = 5.152
Ni
~ 13
a = 3.524
X
–
???
No. 4b (TiH2)Zr40Ni20,
TiH2, Zr, carbonyl Ni,
mechanical activation
870 °С, 2 h
(Ti,Zr)2Ni
57.6
a = 11.935
L-TiZrNi
31.1
a = 5.230; c = 8.560
(Ti,Zr)-α
11.3
a = 3.069; c = 4.824
No. 4c (TiH2)Zr40Ni20,
TiH2, Zr, carbonyl Ni,
mechanical activation
800 °С, 2 h +
EBM
(Ti,Zr)2Ni
29.9
a = 11.907
L-TiZrNi
53.7
a = 5.230; c = 8.548
(Ti,Zr)-α
16.4
a = 3.054; c = 4.898
No. 4d (TiH2)44Zr40Ni16,
TiH2, Zr, carbonyl Ni,
mechanical activation
830 °С, 2.5 h
Ti-α
~ 35
a = 2.975; c = 4.698
Zr-α
~ 50
a = 3.232; c = 5.147
Ni
~ 15
a = 3.514
X
-
???
No. 4e (TiH2)44Zr40Ni16,
TiH2, Zr, carbonyl Ni,
mechanical activation
830 °С, 2.5 h
+ EBM
(Ti,Zr)2Ni
16.0
a = 11.965
L-TiZrNi
61.0
a = 5.251; c = 8.589
(Ti,Zr)-α
23.0
a = 3.087; c = 4.906
No. 5a (TiH2)41.5Zr41.5Ni17,
TiH2, Zr, carbonyl Ni
900 °С,
2 h 10 min
(Ti,Zr)2Ni
72.8
a = 11.985
L-TiZrNi
11.0
a = 5.237; c = 8.581
(Ti,Zr)-α
16.2
a = 3.075; c = 4.894
No. 5b (TiH2)41.5Zr41.5Ni17,
TiH2, Zr, carbonyl Ni
900 °С, 3 h
(Ti,Zr)2Ni
60.2
a = 11.978
L-TiZrNi
12.6
a = 5.231; c = 8.590
(Ti,Zr)-α
27.2
a = 3.067; c = 4.872
No. 5c (TiH2)41.5Zr41.5Ni17,
TiH2, Zr, carbonyl Ni
870…880 °С,
2.5 h
(Ti,Zr)2Ni
51.8
a = 11.964
L-TiZrNi
19.2
a = 5.241; c = 8.577
(Ti,Zr)-α
29.0
a = 3.073; c = 4.853
No. 6a Ti44Zr40(Ni-Pd)16,
TiH2, Zr, fine PNE-1 with
chemically precipitated
Pd ~ 1 wt.%
680…800 °С,
~ 15 h
Ti-α
23.2
a = 2.942; c = 4.679
Zr-α
42.0
a = 3.229; c = 5.141
Ni
23.7
a = 3.507
(Ti,Zr)2Ni
11.1
a = 11.964

With increasing annealing temperature to 910 °С,
there is no significant difference in the structure (after 2
and 3 h of isothermal annealing in a vacuum). The
resulting samples have a similar structure. This is
confirmed by XRD data on the example of sample
Ti41.5Zr41.5Ni17 (see Table 2, No. 5a, 5b). Thus, based on
the XRD results of all synthesized samples, we can
conclude that in the temperature range of 870…900 °C,
an isothermal exposure of 60 min is sufficient for the
complete formation of the final structure. When using
the initial finely dispersed components with a size of
1…10 m, it is first of all important to use finely

ISSN 1562-6016. ВАНТ. 2022. №1(137)








117
dispersed nickel. When using coarse particles, for
example, electrolytic nickel larger than 100 m, for the
formation of a ternary alloy, it is necessary to increase
the sintering temperature to 920…930 °C.
2.6. HEATING RATE
The heating rate significantly affects the dissociation
temperature of titanium and zirconium hydrides. The
higher the heating rate, the stronger the peak of thermal
desorption shifts from the initial TiH2 and ZrН2 to the
region of higher
temperatures. As
shown by
experiments with rapid heating at a rate of more than
10 °C/min after 400 °C, intense gas evolution from the
samples begins and the vacuum pumping system cannot
cope with the released hydrogen. In addition, the intense
release of Н2 upon rapid heating leads to the formation
of large pores in the sample and its swelling.
Conversely, with slow heating at a rate of not more than
5 °C/min, the sample after sintering has a significantly
lower porosity with a pore size of less than 0.5 mm
(unlike large pores with a size of up to 5 mm with rapid
heating). Thus, it was found that the optimum heating
rate is 5 °C/min.
2.7. PRESSURE DURING ANNEALING
The pressure in the chamber during sintering is also
directly related to the dissociation rate of hydrides and
the removal of hydrogen from the samples and,
consequently, to the formation of a ternary alloy. The
better the vacuum during heat treatment, the faster the
cast structure is formed. In addition, the best vacuum
conditions favorably affect the cleaning of the processed
material from volatile impurities. Accordingly, by
improving vacuum conditions, it is possible to reduce
the level of interstitial impurities, primarily from
oxygen. It was shown in [15, 16] that under certain
conditions, partial purification of the material from
oxygen is observed due to the fact that atomic hydrogen
released during the decomposition of titanium and
zirconium hydrides actively interacts with the oxygen of
the oxide layer on the surface of the powders with the
formation of the H2O molecule, which then leaves the
material and is removed by a vacuum pumping system.
And this process takes place the more intensively, the
better the vacuum in the chamber.
2.8. COOLING CONDITIONS
The influence of the cooling conditions of the
samples after sintering in vacuum was investigated in
two versions. The first mode is cooling the sample from
sintering temperature to room temperature together with
the furnace for 20 h. The second mode is the lowering
of the sample from the heating zone and rapid cooling to
room temperature in 30 min (No. 3a, 3b). As shown by
XRD/SEM/EDX studies in both modes, a similar
structure is formed.

2.9. COMPACTING. METHOD OF MIXING THE
ORIGINAL COMPONENTS
In this study, the following methods of mixing the
starting components were tested in the manufacture of
samples:
a) “drunk barrel” mixer for 60…120 min at a
rotational speed of ~ 30…40 rpm;
b) hand rubbing/mixing in alundum mortar;
c) high-energy grinding/mixing in a ball mill.
The results of SEM/EDX studies showed that
manual mixing and mixing in a “drunk barrel” gives an
inhomogeneous distribution of components over the
sample, which
after
sintering
leads
to
local
heterogeneity in elemental and phase composition. This
is especially noticeable when using the starting
components of different dispersions. The best result is
obtained when using short-term joint mechanical
activation of components with the same dispersion.
After sintering, such samples showed the composition
corresponding
to
the given one, without
local
heterogeneities and deviations.
2.10. METHOD OF COMPACTION/PRESSING.
THE EXTENT OF PRESSING
The obtained mixture of powders was compacted
with a different degree of unilaterally pressing: from 3
to 80 t into cylindrical briquette Ø 15…30 mm in
diameter and height 6…25 mm. The data obtained after
the sintering of samples with different degrees of
compaction show that the degree of compaction mainly
affects the porosity of the final material and does not
significantly affect its structural-phase state. In the
course of the work, the optimal pressing parameters
were empirically selected. Given the high fragility of
TiH2 and ZrН2, as well as their low ductility, the
pressing of these samples presents a certain technical
difficulty:
a) at low load (1...10 t), the mixture of the starting
powders is not compressed and the sample crumbles;
b) at high pressure (40...80 t), re-pressing cracks
occur in the sample and the samplecrumbles when
pressed out of the mold.
The mode for pressing samples weighing 35...50 g
was selected experimentally, the load is optimal
(3.3...7.2 t/cm
2
).
Further studies on the synthesis of quasicrystals in
the Ti-Zr-Ni system were carried out on samples of the
composition Ti40Zr40Ni20/Ti44Zr40Ni16. The first is the
theoretically calculated optimal composition for the
formation of the QC phase, according to the literature
[13]. The second corresponds to the composition of
quasicrystals obtained by the hydride cycle technology
at the Institute of Macrokinetics [10].
Samples No. 3a, 3b were synthesized under equal
heat treatment conditions (samples were sintered at the
same time) using finely divided initial components and
selected mixing/pressing parameters. As can be seen
from the data presented, the composition of the samples
affected the final structural phase state. The phase ratio
and lattice parameters have slightly changed. According
to published data, the presence of a certain amount of
the Laves phase of L-TiZrNi and α-(Ti, Zr) is
characteristic of QC materials of the Ti-Zr-Ni system.
Therefore, subsequent studies were carried out with the
same compounds, but aimed at reducing the oxygen
content. The use of finely dispersed starting components
and mechanical activation grinding in a planetary mill
made it possible to lower the sintering temperature with
the formation of a triple alloy to 870 °C. However, as
can be seen from the above XRD data, sintering does

118

ISSN 1562-6016. ВАНТ. 2022. №1(137)
not occur at lower temperatures. Samples that were
annealed at low temperature and in which there was no
interaction between the components were subjected to
vacuum refining in an electron beam melting unit in
order to reduce the content of interstitial impurities
(primarily oxygen).
2.11. EFFECT OF IMPURITIES
As it turned out during the research, this is the most
important parameter affecting the formation of a QC
structure. Regardless of carefully selected optimal
parameters of the heat treatment modes using the
hydride cycle technology, the presence of interstitial
impurities (O2, N2, C) adversely affects the formation of
quasicrystals. Thus, with oxygen content in the sample
exceeding 3000 ppm (0.3 wt.%), the formation of the
QC phase is leveled due to the stabilization of the
(Ti, Zr)2Ni phase by oxygen and the formation of the
Laves phase L-TiZrNi instead of quasicrystals. Given
that active metals such as titanium and zirconium,
which have a high affinity for oxygen, are used, it is
extremely difficult to reduce the concentration of O2 in
the samples. Especially considering that the initial raw
materials are finely divided powders with a highly
developed surface on which a significant amount of gas
impurities is adsorbed. This is currently the main
problem in obtaining stable quasicrystals in the Ti-Zr-Ni
system using the proposed hydride cycle technology. At
this point, attention was repeatedly paid to publications
on quasicrystals synthesis by other methods. Thus, the
use of the fast quenching method allows one to slightly
increase the limiting oxygen content in the samples, and
high cooling rates suppress the precipitation of the
(Ti, Zr)2Ni phase and the Laves phase of L-TiZrNi
forming quasicrystals [5]. It was theoretically proved
[18, 19] that quasicrystals is a low-temperature stable
phase in the Ti40Zr40Ni20-Ti41.5Zr41.5Ni17 system, while
the Laves phase L-TiZrNi is stable at high temperatures
(at T > 700 °C).
To confirm the significant effect of interstitial
impurities on the final structure of alloys of the Ti-Zr-Ni
system, we studied the effect of refining electron-beam
remelting
of
samples No. 4a, 4d
annealed
at
temperatures insufficient to obtain a ternary alloy. An
important result of this study is that a favorable effect of
refining remelting on the structural state of the alloy
was established. As can be seen from Table 2, the phase
composition of the samples after electron beam melting
No. 4c, 4e dramatically differs in the ratio of the phases
L-TiZrNi and (Ti, Zr)2Ni compared with samples of the
same composition after
sintering
(for example
No. 3a, 3b). An increase in the amount of the L-TiZrNi
phase is proportional to a decrease in the amount of the
(Ti, Zr)2Ni phase. This indicates that, during the melting
in a vacuum, the oxygen content in the sample
decreases, which is responsible for the appearance of
the (Ti, Zr)2Ni phase in the composition region
corresponding to the L-TiZrNi phase (high-temperature
phase of the Ti-Zr-Ni system). In addition, it was found
that in samples No. 4a, 4d annealed at temperatures of
800 and 830 °C, in which dehydrogenation occurred,
but the alloy did not form, the self-propagating high-
temperature synthesis in the layer-by-layer combustion
mode started at the beginning of the EBM. In this case,
the sample was heated above the melting point and
began to melt. Therefore, a small addition of electron
beam power led to the complete melting of the sample.
The discovered phenomenon led to additional studies
aimed at testing the feasibility of synthesizing samples
of the Ti-Zr-Ni system in the SHS mode. In Ti-Ni and
Zr-Ni binary systems, a solid-phase interaction reaction
in the SHS mode is possible due to their negative heats
of mixing
(Ti-Ni) = -35 kJ/mol [20] and

(Zr-Ni) = -49 kJ/mol, respectively. Those, it is quite
possible that such processes can occur in the ternary
Ti-Zr-Ni system.
Fig. 6 shows the appearance of (TiH2)40Zr40Ni20
samples after pressing and heat treatment in a vacuum
under various conditions. The above images clearly
show the changes that the samples undergo, depending
on the selected modes.


a


b


c


d
Fig. 6. Appearance of samples (TiH2)40Zr40Ni20: a – initial after pressing; b – No. 4a after annealing in vacuum at
T = 800 °С; c – No. 4b after annealing in vacuum at T = 870 °С for 2 h; d – No. 4c after annealing in vacuum at
T = 800 °С + SHS on EBM

According to the Tamman-Hedwal theory of
mechanisms of solid-phase interaction, supplemented by
Wagner's theory, it follows that activated states
significantly accelerate the course of solid-phase
reactions. As indicated above, in the process of hydride
dissociation, diffusion processes are activated. Due to
an increase in the defect of the crystal structure due to
phase transformations and volume effects during
thermal desorption of hydrogen, as well as active
diffusion of hydrogen, the processes of solid-phase
interaction are significantly activated. Accordingly, the
temperatures of the onset of the interaction of the
particles of the starting components with each other can
be lower than during fusion by traditional methods. In
addition, according to Hedwal, if one substance can
undergo a polymorphic transformation, then this
transformation is a very favorable moment for the
reaction of the interaction of two solids. Or in other

ISSN 1562-6016. ВАНТ. 2022. №1(137)








119
words, in the case of a polymorphic transformation of
one of the components of the mixture at a relatively low
temperature, the chemical reaction begins and proceeds
intensively
at
the point of
this polymorphic
transformation. In the case of the Ti-Zr-Ni system, there
are two components with a polymorphic transition in the
temperature range 863...883 °C for Zr and Ti,
respectively. As further studies showed, in the synthesis
of samples of composition (TiH2)41.5Zr41.5Ni17 (in at.%,
powder TiH2, Zr, fine PNE-1, without mechanical
activation), thermocouples in direct contact with the
sample recorded a sharp jump in temperature from 865
up to 954 °C, ΔT = 89 °C. This indicates the occurrence
of an exothermic reaction of solid-phase interaction in
the “thermal explosion” mode. This was confirmed by
visual observation during the heating of samples in a
quartz ampoule. A graph of the temperature dependence
of the sample during synthesis is shown in Fig. 7.

Fig. 7. The temperature change of the pressed sample
(TiH2)41.5Zr41,5Ni17 upon heating in vacuum
Thus, it turned out that, in fact, the synthesis of a
ternary Ti-Zr-Ni alloy does not occur by the mechanism
of slow diffusion solid-phase sintering, but in the
process of a short-term exothermic reaction between
particles of Ti, Zr, and Ni, occurring in the thermal
explosion mode. It is also possible to synthesize in a
layer-by-layer combustion mode during preliminary
annealing in the temperature range 800…830 °С to
remove hydrogen and subsequent local initiation of
SHS. However, for the successful synthesis of a ternary
alloy, it is necessary to use finely dispersed starting
components with a size of 1…10 μm, since in the case
of different dispersion the temperature of initiation of
the SHS reaction increases significantly and local
heterogeneities in composition arise. The structural
phase state of the final material depends on the presence
of interstitial impurities, primarily on the oxygen
content. Because in this study, the total amount of
oxygen in the starting components exceeded 3000 ppm,
and samples with a QC structure were not obtained. To
form a QC structure using the hydride cycle technique,
it is necessary to reduce the oxygen content in the
samples. The following options are possible for this:
– use of starting high-purity components (powders
of Ti, Zr, Ni);
– hydrogenation of Ti and Zr with high-purity
hydrogen;
– use of deoxidizing / microalloying Al, Y, Sc.
3. CONCLUSIONS
In this work, the main key parameters of the
formation of intermetallic compounds of the Ti-Zr-Ni
system by the “hydride cycle” method are established.
The optimal modes of the technological chain of sample
production were selected. The heat treatment parameters
are empirically selected and their influence on the
structural state of the synthesized alloys is determined.
The influence of various factors on the synthesis process
and on the final structural phase state of materials has
been established. It has been established that the key
factors in the formation of ternary compounds of the
Ti-Zr-Ni system during hydride dissociation are the
dispersion and homogeneity of the initial compacted
components.
The causes of the destruction of the QC phase and
the formation of substituent phases are determined: the
Laves phase of L-TiZrNi and the phase (Ti, Zr)2Ni
arising from the high oxygen content. Regardless of the
initial composition, all samples of Ti40.5Zr31.9Ni27.6,
Ti41.5Zr41.5Ni17, Ti40Zr40Ni20, Ti44Zr40Ni16 contained the
dominant phase (Ti, Zr)2Ni and a smaller amount of L-
TiZrNi and (Ti, Zr)-α. Mechanisms for reducing the
oxygen content are proposed and the efficiency of using
refining remelts in vacuum to reduce interstitial
impurities is shown.
It was found that during the “hydride cycle” the
synthesis of ternary alloys in the Ti-Zr-Ni system occurs
during a short-term exothermic reaction related to SHS
and proceeding in the “thermal explosion” mode. SHS
begins in the temperature region corresponding to the
α↔β polymorphic transformation of titanium and
zirconium.

FUNDING

This work was supported by non-profit corporation
Quantum Gravity Research, CA, USA.

REFERENCES

1. R.M. Stroud,
A.M. Viano,
E.H. Majzoub,
P.C. Gibbons, K.F. Kelton. Ti-Zr-Ni quasicrystals:
structure and hydrogen storage // Materials Research
Society. Symp. Proc. 1996, N 400, p. 255-260.
2. R.M. Stroud, K.F. Kelton, S.T. Misture. High-
temperature x-ray and calorimetric studies of phase
transformations in quasicrystalline Ti-Zr-Ni alloys // J.
Mater. Res. 1997, N 12(2), p. 434-438.
3. I. Zavaliy, G. Wojcik, G. Mlynarek, I. Saldan,
V. Yartys, M. Kopczyk. Phase-structural characteristics
of (Ti1-xZrx)4Ni2O0.3 alloys and their hydrogen gas
and electrochemical absorption-desorption properties //
Journal of Alloys and Compounds. 2001, N 314, p. 124-
131.
4. O.Ye. Dmytrenko, I.V. Kolodiy. Influence of the
hydrogen saturation temperature on the structure of
melt-spun Ti30Zr45Ni25 alloys // Problems of Atomic
Science and Technology. Series “Vakuum, Pure
materials, Superconductors” (22). 2018, N 1(113),
p. 162-168.
5. V.M. Azhazha, A.M. Bovda, S.D. Lavrinenko,
L.V. Onishchenko, S.V. Malykhin, A.T. Pugachev,
M.V. Reshetnyak, A.N. Stetsenko, B.A. Savitsky.
Synthesis and stability of Ti-Zr-Ni quasicrystals //
0
100
200
300
400
500
600
700
800
900
1000
0
5000
10000
15000
20000
25000
30000
Time, sec
Temperature, °Сime, s

120

ISSN 1562-6016. ВАНТ. 2022. №1(137)
Problems of Atomic Science and Technology. Series
“Vacuum, Pure materials, Superconductors”. 2007,
N 4, p. 82-87.
6. S.K. Dolukhanyan, A.G. Aleksanyan, V.Sh. She-
khtman, A.A. Mantashyan, D.G. Mailyan, O.P. Ter-
Galstyan. A new method for producing alloys based on
transition metals // Chemical Journal of Armenia. 2007,
N 60(4), p. 545-569.
7. S.K. Dolukhanyan, A.G. Aleksanyan, O.P. Ter-
Galstyan, V.Sh. Shekhtman, M.K. Sakharov, G.E. Ab-
rosimova. Specifics of the formation of alloys and their
hydrides in the Ti-Zr-H system // Russ. J. Phys. Chem.
B. 2007, N 2(6), p. 563-569.
8. A.G. Aleksanyan, S.K. Dolukhanyan, A.A. Man-
tashyan, D.G. Mailyan, O.P. Ter-Galstyan, V.Sh. She-
khtman. A new technique for producing alloys based on
transition metals // Carbon nanomaterials in clean
energy hydrogen systems. Springer, 2008, p. 783-794.
9. S.K. Dolukhanyan, A.G. Aleksanyan, V.Sh. She-
khtman, H.G. Hakobyan, D.G. Mayilyan, N.N. Agha-
djanyan, K.A. Abrahamyan, N.L. Mnatsakanyan,
O.P. Ter-Galstyan. Synthesis of
transition metal
hydrides and a new process for production of refractory
metal alloys
//
International Journal of Self-
Propagating High-Temperature
Synthesis.
2010,
N 19(2), p. 85-93.
10. V.Sh. Shekhtman, H.G. Hakobyan, A.G. Alek-
sanyan,
S.K. Dolukhanyan, O.P. Ter-Galstyan,
M.K. Sakharov. The formation of quasicrystals and their
hydrides in Ti-Zr-Ni system // International Journal of
hydrogen energy. 2011, N 36, p. 1206-1208.
11. D.G. Savvakin, M.М. Gumenyak. Synthesis of
alloys based on the binary Zr-Ti system using dispersed
zirconium hydride // Metallophysics and the Latest
Technology. 2013, N 35(3), p. 349-358.
12. O.M. Ivasishin, V.N. Voyevodin, P.E. Mar-
kovsky, M.M. Pylypenko, D.G. Savvakin, S.D. Lav-
rinenko, O.P. Karasevska. The microstructure and
characteristics of the Zr-1% Nb alloy synthesized from
heterogeneous powder mixtures // Problems of Atomic
Science and Technology. 2015, N 2(96), p. 65-72.
13. J.B. Qiang, Y.M. Wang, D.H. Wang,
M. Kramer, P. Thiel, C. Dong. Quasicrystals in the Ti-
Zr-Ni alloy system // Journal of Non-crystalline Solids.
2004, N 334&335, p. 223-227.
14. О.М. Ivasishin, А.В. Bondarchuk, M.М. Gu-
menyak, D.G. Savvakin. Surface phenomenon upon
heating of titanium hydride powder // Physics and
Chemistry of Solid State. 2011, N 12(4), p. 900-907.
15. О.М. Ivasishin, D.G. Savvakin, M.М. Gume-
nyak. Dehydrogenation of titanium hydride powder and
its role in sintering activation // Metallophysics and
Latest Technologies. 2011, v. 33, N 7, p. 899-917.
16. D.G. Savvakin, N.M. Humenyak, M.V. Mat-
viychuk, O.G. Molyar. The role of hydrogen in sintering
of titanium powders // Physicochemical Mechanics of
Materials. 2011, N 5, p. 72-81.
17. О.М. Ivasishin, D.G. Savvakin. Synthesis of
alloys based on zirconium and titanium using their
hydrides // Physicochemical Mechanics of Materials.
2015, N 4, p. 27-35.
18. R.G. Hennig, A.E. Carlsson, K.F. Kelton,
C.L. Henley. Ab initio Ti-Zr-Ni phase diagram predicts
stability of icosahedral TiZrNi quasicrystals // Physical
Review B. 2005, N 71, p. 144103-1-10.
19. R.G. Hennig, A.E. Carlsson, K.F. Kelton,
C.L. Henley. Icosahedral Ti-Zr-Ni: A groundstate
quasicrystal? eprint arXiv:cond-mat/0205202 [cond-
mat.mtrl-sci]. May 2002.
20. É. Fazakas, L.K. Varga. Effect of valence
electron concentration on the glass-forming ability in
Al-based alloys // International Journal of Engineering
and Applied Sciences (IJEAS). 2015, N 2(11), p. 115-
121.
Article received 24.11.2021


СИНТЕЗ Ti-Zr-Ni-СПЛАВОВ МЕТОДОМ «ГИДРИДНОГО ЦИКЛА»

А.Е. Дмитренко, И.В. Колодий, Т.Б. Янко, В.М. Борисенко, К. Ирвин, Р.Л. Василенко

Проведены комплексные исследования технических параметров и условий синтеза тройных сплавов в
системе Ti-Zr-Ni методом «гидридного цикла». Определено влияние на процесс синтеза таких параметров,
как: температура и время отжига, скорость нагрева, условия охлаждения, состав материала, дисперсность,
содержание водорода в используемых гидридах, наличие примесей, способы смешивания и прессования, а
также степень прессования исходных компонентов. Синтезированы и исследованы сплавы следующих
составов: Ti40,5Zr31,9Ni27,6, Ti41,5Zr41,5Ni17, Ti40Zr40Ni20, Ti44Zr40Ni16. Определены оптимальные технологические
параметры и условия синтеза тройных сплавов. Установлено, что ключевыми факторами в процессе
образования соединений при диссоциации гидридов являются дисперсность и однородность исходных
спрессованных компонентов. Установлено, что синтез тройных сплавов в системе Ti-Zr-Ni происходит в
ходе кратковременной экзотермической реакции в режиме «теплового взрыва», которая начинается в
области температур, соответствующей полиморфному превращению α↔β циркония и титана.


СИНТЕЗ Ti-Zr-Ni-СПЛАВІВ МЕТОДОМ «ГІДРИДНОГО ЦИКЛУ»

О.Є. Дмитренко, І.В. Колодій, Т.Б. Янко, В.М. Борисенко, К. Ірвін, Р.Л. Василенко

Проведено комплексне дослідження технічних параметрів та умов синтезу потрійних сплавів у системі
Ti-Zr-Ni методом «гідридного циклу». Було визначено вплив на процес синтезу таких параметрів, як:

ISSN 1562-6016. ВАНТ. 2022. №1(137)








121
температура і час відпалу; швидкість нагрівання; умови охолодження; склад матеріалу; дисперсність; вміст
водню в гідридах, що використовуються; наявність домішок; способи змішування і пресування, а також
ступінь пресування вихідних компонентів. Синтезовано та досліджено сплави наступних складів:
Ti40,5Zr31,9Ni27,6, Ti41,5Zr41,5Ni17, Ti40Zr40Ni20, Ti44Zr40Ni16. Визначено оптимальні технологічні параметри та
умови синтезу потрійних сплавів. Встановлено, що ключовими факторами в процесі утворення сполук при
дисоціації гідридів є дисперсність та однорідність вихідних спресованих компонентів. Встановлено, що
синтез потрійних сплавів у системі Ti-Zr-Ni відбувається в ході короткочасної екзотермічної реакції в
режимі «теплового вибуху», яка починається в області температур, що відповідає поліморфному
перетворенню α↔β цирконію та титану.