Study of characteristics of Al + 5 wt.% TiO₂ + 6 wt.% Gr hybrid p/m composite powders prepared by ball milling process
This paper is an attempt to understand the characteristics of Al + TiO₂ + Gr hybrid ball milled composite powders, which is anticipated to have large application in the near future. Aluminium with titanium dioxide (TiO₂) and graphite (Gr) powders was ball milled in order to yield the composition...
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Фізико-механічний інститут ім. Г.В. Карпенка НАН України
2015
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| Цитувати: | Study of characteristics of Al + 5 wt.% TiO₂ + 6 wt.% Gr hybrid p/m composite powders prepared by ball milling process / M. Ravichandran, VS. Vidhya, V. Anandakrishanan // Фізико-хімічна механіка матеріалів. — 2015. — Т. 51, № 4. — С. 136-143. — Бібліогр.: 16 назв. — англ. |
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irk-123456789-1362522018-06-17T03:03:58Z Study of characteristics of Al + 5 wt.% TiO₂ + 6 wt.% Gr hybrid p/m composite powders prepared by ball milling process Ravichandran, M. Vidhya, VS. Anandakrishanan, V. This paper is an attempt to understand the characteristics of Al + TiO₂ + Gr hybrid ball milled composite powders, which is anticipated to have large application in the near future. Aluminium with titanium dioxide (TiO₂) and graphite (Gr) powders was ball milled in order to yield the composition like: Al + 0% TiO₂, Al + 5% TiO₂, Al + 5% TiO₂ + 2% Gr, Al + 5% TiO₂ + 4% Gr and Al + 5% TiO₂ + 6% Gr. From the X-Ray diffraction analysis of the milled powders, the grain size, lattice space, lattice constant, stress, strain, dislocation density and unit cell volume were calculated. Compressibility was performed in a hardened steel die at pressures between 100 to 500 MPa to determine Al with 5 wt.% TiO₂ and 2 & 4 wt.% of Gr powder mixtures. For understanding of compaction behavior of aluminum based hybrid composites reinforced with TiO₂ and Gr particles under various applied pressure conditions, experimental research has been made using several powder compaction equations. Microstructure analysis for Al + 5% TiO₂ + 6% Gr composite has been reported. Вивчали характеристики композитних порошків Al + TiO₂ + Gr. Композити складу Al + 0% TiO₂, Al + 5% TiO₂, Al + 5% TiO₂ + 2% Gr, Al + 5% TiO₂ + 4% Gr та Al + 5% TiO₂ + 6% Gr отримували шляхом кульового помелу відповідних компонентів. Для визначення розмірів зерен, параметрів кристалічної решітки, напруження, деформації, густини дислокацій та об’єму елементарної комірки використовували рентгенівський дифракційний аналіз. Здатність до компактування Al з сумішшю порошків 5 wt.% TiO₂ та 2 і 4 wt.% Gr визначали в гартованих сталевих прес-формах за тиску 100… 500 МPа. Для розуміння особливостей компактування гібридних композитів на основі Al, зміцнених частинками TiO₂ та Gr за різних тисків, виконували експериментальні дослідження з використанням декількох підходів. Наведено мікроструктурний аналіз композита Al + 5% TiO₂ + 6% Gr. Изучали характеристики композитных порошков Al + TiO₂ + Gr. Композиты состава Al + 0% TiO₂, Al + 5% TiO₂, Al + 5% TiO₂ + 2% Gr, Al + 5% TiO₂ + + 4% Gr и Al + 5% TiO₂ + 6% Gr получали путем шарового помола соответствующих компонентов. Для определения размеров зерен, параметров кристаллической решетки, напряжения, деформации, плотности дислокаций и объема элементарной ячейки использовали рентгеновский дифракционный анализ. Способность к компактированию Al со смесью порошков 5 wt.% TiO₂ и 2…4 wt.% Gr определяли в закаливаемых стальных пресс-формах при давлении 100...500 МPа. Для понимания особенностей компактирования гибридных композитов на основе Al, упрочненных частицами TiO₂ та Gr при различных давлениях, проводили экспериментальные исследования с использованием нескольких подходов. Представлен микроструктурный анализ композита Al + 5% TiO₂ + 6% Gr. 2015 Article Study of characteristics of Al + 5 wt.% TiO₂ + 6 wt.% Gr hybrid p/m composite powders prepared by ball milling process / M. Ravichandran, VS. Vidhya, V. Anandakrishanan // Фізико-хімічна механіка матеріалів. — 2015. — Т. 51, № 4. — С. 136-143. — Бібліогр.: 16 назв. — англ. 0430-6252 http://dspace.nbuv.gov.ua/handle/123456789/136252 en Фізико-хімічна механіка матеріалів Фізико-механічний інститут ім. Г.В. Карпенка НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| description |
This paper is an attempt to understand the characteristics of Al + TiO₂ + Gr hybrid ball
milled composite powders, which is anticipated to have large application in the near future.
Aluminium with titanium dioxide (TiO₂) and graphite (Gr) powders was ball milled in
order to yield the composition like: Al + 0% TiO₂, Al + 5% TiO₂, Al + 5% TiO₂ + 2% Gr,
Al + 5% TiO₂ + 4% Gr and Al + 5% TiO₂ + 6% Gr. From the X-Ray diffraction analysis
of the milled powders, the grain size, lattice space, lattice constant, stress, strain, dislocation
density and unit cell volume were calculated. Compressibility was performed in a
hardened steel die at pressures between 100 to 500 MPa to determine Al with 5 wt.% TiO₂
and 2 & 4 wt.% of Gr powder mixtures. For understanding of compaction behavior of aluminum
based hybrid composites reinforced with TiO₂ and Gr particles under various
applied pressure conditions, experimental research has been made using several powder
compaction equations. Microstructure analysis for Al + 5% TiO₂ + 6% Gr composite has
been reported. |
| format |
Article |
| author |
Ravichandran, M. Vidhya, VS. Anandakrishanan, V. |
| spellingShingle |
Ravichandran, M. Vidhya, VS. Anandakrishanan, V. Study of characteristics of Al + 5 wt.% TiO₂ + 6 wt.% Gr hybrid p/m composite powders prepared by ball milling process Фізико-хімічна механіка матеріалів |
| author_facet |
Ravichandran, M. Vidhya, VS. Anandakrishanan, V. |
| author_sort |
Ravichandran, M. |
| title |
Study of characteristics of Al + 5 wt.% TiO₂ + 6 wt.% Gr hybrid p/m composite powders prepared by ball milling process |
| title_short |
Study of characteristics of Al + 5 wt.% TiO₂ + 6 wt.% Gr hybrid p/m composite powders prepared by ball milling process |
| title_full |
Study of characteristics of Al + 5 wt.% TiO₂ + 6 wt.% Gr hybrid p/m composite powders prepared by ball milling process |
| title_fullStr |
Study of characteristics of Al + 5 wt.% TiO₂ + 6 wt.% Gr hybrid p/m composite powders prepared by ball milling process |
| title_full_unstemmed |
Study of characteristics of Al + 5 wt.% TiO₂ + 6 wt.% Gr hybrid p/m composite powders prepared by ball milling process |
| title_sort |
study of characteristics of al + 5 wt.% tio₂ + 6 wt.% gr hybrid p/m composite powders prepared by ball milling process |
| publisher |
Фізико-механічний інститут ім. Г.В. Карпенка НАН України |
| publishDate |
2015 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/136252 |
| citation_txt |
Study of characteristics of Al + 5 wt.% TiO₂ + 6 wt.% Gr hybrid p/m composite powders prepared by ball milling process / M. Ravichandran, VS. Vidhya, V. Anandakrishanan // Фізико-хімічна механіка матеріалів. — 2015. — Т. 51, № 4. — С. 136-143. — Бібліогр.: 16 назв. — англ. |
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Фізико-хімічна механіка матеріалів |
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136
Ô³çèêî-õ³ì³÷íà ìåõàí³êà ìàòåð³àë³â. – 2015. – ¹ 4. – Physicochemical Mechanics of Materials
STUDY OF CHARACTERISTICS OF Al + 5 wt.% TiO2 + 6 wt.% Gr
HYBRID P/M COMPOSITE POWDERS PREPARED
BY BALL MILLING PROCESS
M. RAVICHANDRAN 1, VS. VIDHYA 2, V. ANANDAKRISHANAN 3
1 Department of Mechanical Engineering, Kings College of Engineering, Pudukkottai, India;
2 Department of Chemistry, Chendhuran College of Engineering and Technology, Pudukkottai, India;
3 Department of Production Engineering, National Institute of Technology, Tiruchirappalli,
Tamilnadu, India
This paper is an attempt to understand the characteristics of Al + TiO2 + Gr hybrid ball
milled composite powders, which is anticipated to have large application in the near future.
Aluminium with titanium dioxide (TiO2) and graphite (Gr) powders was ball milled in
order to yield the composition like: Al + 0% TiO2, Al + 5% TiO2, Al + 5% TiO2 + 2% Gr,
Al + 5% TiO2 + 4% Gr and Al + 5% TiO2 + 6% Gr. From the X-Ray diffraction analysis
of the milled powders, the grain size, lattice space, lattice constant, stress, strain, disloca-
tion density and unit cell volume were calculated. Compressibility was performed in a
hardened steel die at pressures between 100 to 500 MPa to determine Al with 5 wt.% TiO2
and 2 & 4 wt.% of Gr powder mixtures. For understanding of compaction behavior of alu-
minum based hybrid composites reinforced with TiO2 and Gr particles under various
applied pressure conditions, experimental research has been made using several powder
compaction equations. Microstructure analysis for Al + 5% TiO2 + 6% Gr composite has
been reported.
Key words: ball milling, synthesis, composite powders, ball milling.
Aluminum matrix composites are used for various applications in aerospace, auto-
mobile, military and electronic industry due to their low density, high toughness, good
mechanical properties and high corrosion resistance [1]. Many varieties of reinforce-
ments are used to produce the aluminium matrix composites. Instead of all, the titani-
um-di-oxide (TiO2) also found as a good one, since it has high hardness, high modulus,
and wear resistance [2]. Adding of single reinforcement to the matrix material im-
proves the strength and hardness of the material, but it leads to the machining problem
[3]. Recently aluminum alloy–graphite particulate composite is being used in various
applications because of its low friction and wear, improved machinability, low thermal
expansion and high damping density [4]. In this work both the hard TiO2 and soft gra-
phite powders are used as reinforcements to produce the aluminium hybrid composites
and it is expected to be used for various application. The mechanical alloying process
is used to produce the advanced composite materials [5]. Mechanical alloying is a wi-
dely used technique in synthesizing nanocrystalline materials and also it has been used
to prevent the reinforcement clusters or agglomerates on the matrix, especially in the
case of small size reinforcement particles that produce uniform dispersion in the mat-
rix. The homogeneous dispersion of fine reinforced particles in a fine grained matrix is
beneficial to the mechanical properties of metal matrix composites [2]. A number of re-
search works have been performed on processing of aluminum matrix composites via
mechanical milling. Meanwhile, mechanical milling affects the morphology and hard-
ness of powder particles, thus it influences the compressibility of milled powders [6].
Corresponding author: M. RAVICHANDRAN, e-mail: smravichandran@hotmail.com
137
Materials are characterized by a grain size or particulate size of up to about 100 nm.
These materials exhibit enhanced mechanical, magnetic, elevated temperature, optical,
and excellent catalytic properties [7]. It was reported that the high-energy ball milling
has been used to improve particle distribution throughout the matrix [8]. The micro-
structure analysis of Al–Al2O3 composite produced by mechanical alloying method
was studied in [9]. In [10] the authors synthesized high volume fraction Al–Al2O3 nano
composite powders by high-energy milling and studied the characteristics of the milled
powders. X-ray diffraction is a convenient method for determining the mean size of
crystallites in crystalline bulk materials. The first scientist, Paul Scherrer, published his
results in a paper that included what became known as the Scherrer equation in 1981.
This can be attributed to the fact that “crystallite size” is not synonymous with “particle
size”, while X-Ray diffraction is sensitive to the crystallite size inside the particles.
The aim of present work is to prepare aluminium hybrid composite powders that
consist of TiO2 and Gr by using ball milling process. An attempt was made to calculate
the grain size, lattice strain, stress, lattice space, lattice constant, dislocation density
and unit cell volume of mechanically milled powders. The grain size was calculated by
using Williamson-Hall and Scherrer equations. Microstructure analysis was carried out
to reveal the presence of reinforcement particles during ball milling.
Experimental details. Atomized aluminium (Al) powder size of –325 mesh and
purity of 99.7% supplied by Kemphasol, Mumbai, India was used for the matrix mate-
rial and rutile phase of titanium-di-oxide (TiO2) and graphite powders supplied by the
Acechemie (India) were used as the reinforcement material. Natural Graphite is a mi-
neral consisting of graphitic carbon. It varies considerably in crystallinity. Natural
graphite is an excellent conductor of heat and electricity. It is stable over a wide range
of temperatures. Graphite is a highly refractory material with a high melting point
(3650°C). The required mass of Al, TiO2 and Gr were accurately weighed in an electro-
nic weighing machine. The powders were milled for 20 h in a ball mill with a speed of
100 r/min. The vial of the ball mill is made up of high hardened stainless steel material.
Hardened high speed steel balls with a diameter of 10 mm were used and the ball-to-
powder ratio was 1:1. X-ray diffraction analysis was carried out using PANalyti-
calX’Pert X-ray diffractometer CuKα target, (λ = 1.5418 Å) to determine the lattice
space, lattice constant, grain size, lattice strain, stress, dislocation density and unit cell
volume of the milled composite powders by the following equations [11].
The grain size was calculated using Williamson-Hall equation:
( )cos 2 sin
k
t
λ β θ = + ε θ
, (1)
where k is the shape factor (0.94); λ is the wavelength of the X-ray used (λ = 1.5406 Å);
θ is the Bragg diffraction angle and β is the FWHM in radian; t is the effective
crystallite size; ε is the strain value.
The Scherrer Equation is given by
0.94
cos
D
λ=
β θ
. (2)
The strain value (ε) can be evaluated by using the following relation:
sin tanD
λ β ε = − θ θ
, (3)
where D is the grain size.
The dislocation density (δ) has been calculated by using the formula:
15
aD
εδ = , (4)
138
where ε is the strain value; a is the lattice parameter; D is the grain size.
The stress was calculated by using the formulae:
0
02
a aE
S
a
−
= δ
(5)
The FWHM is calculated by the equation,
( )(2 high 2 low) /180Xβ = θ − θ π (6)
The lattice parameter was determined for each of the diffracting planes from XRD
patterns.
2 2 2
2 2
1 h k l
d a
+ += ,
where E is the Young’s modulus of the powder; δ is the Poission’s ratio of the pow-
ders; a0 is the bulk lattice constant and a is lattice constant of the powders. In order to
study the compressibility of the different powder blends, the density after compaction
at pre-determined pressure was measured and recorded. The compressibility of powder
mixtures were carried out using computerized universal testing machine of 400 kN
capacity (Venus Instruments, India; Model: UTV-40PC, SR No.: 2011/[4084]) with
suitable punch and die. The known values of relative densities and applied pressure
have been used in the Heckel and Balshin compaction equation to validate the results.
Standard deviation from the linearity of the measured values and regression equations
for all samples were determined using Origin-8 software.
The milled Al + 5% TiO2 + 6% Gr hybrid composite powders were compacted in
400 kN hydraulic press using punch and die. The compaction pressure was 500 MPa
and the specimen dimensions were 24 mm diameter and 12 mm height. The sintering
was done in a muffle furnace at the temperature of 590°C for a period of 3 h. The SEM
analysis of the sintered Al + 5% TiO2 + 6% Gr composite was conducted using FEI
Quanta FEG 200-SEM. The microstructure analyses were carried out for the sintered
hybrid composite specimen using an optical microscope and image analyzing software
(Media Image Technologies Pvt. Ltd. Hyderabad) to study the grain boundary, bonding
between the matrix and reinforcements.
Results and discussion. XRD analy-
sis of milled powders. The XRD patterns
of Al + 0% TiO2, Al + 5% TiO2, Al + 5%
TiO2 + 2% Gr and Al + 5% TiO2 + 4% Gr
composite powders, reported in previous
publication are used to calculate the struc-
tural parameters [12]. In this study XRD
pattern of Al + 5% TiO2 + 6% Gr compo-
site powders is provided in Fig. 1. The
calculation of particle size, stress, unit cell
volume, dislocation density, lattice cons-
tant and lattice strain of mechanically
milled powders is very important since the
phase constitution and transformation
characteristics appear to be critically dependent on the above said properties. Average
grain size, strain, stress and dislocation density are calculated using Eqs. (1)–(5) for all
the composite powder blends and all the values are tabulated in Table. The cold wor-
king or plastic deformation of metal powders has been shown to produce appreciable
changes in the intensity distribution of diffracted X-rays.
Fig. 1. XRD patterns of
Al + 5% TiO2 + 6% Gr composite powders.
139
Structural characteristic of Al + 0% TiO2 (1), Al + 5% TiO2 (2),
Al + 5% TiO2 + 2% Gr (3), Al + 5% TiO2 + 4% Gr (4)
and Al + 5% TiO2 + 6% Gr (5) powders
Lattice, Å
space constant
D (Scherrer),
nm
ε,
×10–3
D (WH),
nm
Stress
1010,
dyne/cm2
Dislocation
density,
lines/m2
Unit cell
volume
10–29,
Å
1.75 4.043 109.63±0.13 0.336 142.733±0.21 0.191 1.182⋅1014 6.607
3.05 5.919 168.07±0.11 0.672 178.471±0.14 1.857 5.762⋅1014 13.306
3.93 5.923 149.75±0.17 0.884 188.764±0.19 4.805 3.316⋅1018 13.342
3.45 4.967 136.56±0.08 0.672 174.843±0.23 5.483 8.251⋅1017 9.879
3.46 4.987 179.98±0.16 0.538 224.624±0.13 4.253 1.504⋅1017 9.999
Fig. 2 shows the effect of reinforcement addition on the grain size which is calcu-
lated by using Williamson-Hall and Scherrer Equations. It is observed from Fig. 2 that
the increase in grain size has been observed for the addition of 5 weight percentage of
TiO2 to the Al matrix. The grain size increases with the addition of increasing weight
percentage of graphite due to the agglomeration of the particles. The powder particle
size is changing with milling time, as a result of the two opposing factors of cold wel-
ding and fracturing of powder particles. While cold welding increases the particle size,
fracturing reduces the particle size. Hence, under continued milling with increasing
weight percentage of graphite powders the particle size increases. It is expected that the
addition of hard nature of TiO2 powders will decrease the grain size. But here the
increase in the grain size observed in the present study could be because of minimum
milling time and energy. However the similar results were obtained in [14], the authors
reported for the 2024 aluminum composites reinforced with various weight percentages
of TiO2 nanoparticles in the early stage of the milling, the A2024 powders are flattened
by the collisions of ball–powder–ball. After this, TiO2 particles are embedded into the
A2024 powders and progressively dispersed in the matrix. Increased average particle
size of the 12 h milled powder confirms that the A2024 powders undergo repeating
plastic deformation, fracturing, and cold welding process [13]. The maximum stress
strain values are obtained for the Al + 5% TiO2 + 6% Gr composite powders. In [2] it
was reported that when comparing with nano Al–TiO2 composite the grain size of mic-
rocomposite is higher due to the more agglomeration of TiO2 with aluminium matrix.
Thus the agglomeration of reinforcement powders plays vital role during mecahnical
milling process.
Compressibility of Al–TiO2–Gr mixture powders. The experimental procedure of
Al–TiO2–Gr mixture powders compaction and the densification curves were presented
in previous works [13]. In this study the Al+5%TiO2+6%Gr powder mixture is compa-
red with other composition of mixtures. The correlation between TiO2 and Gr amount
and relative density is shown in Fig. 3. It is noted that the maximum densification (98.4)
was obtained for the unreinforced aluminium under the pressure of 500 MPa. However
for the same compaction pressure the densification obtained for the Al + 5% TiO2 + 6% Gr
hybrid composites is 93.2%. The similar results were also reported in [14] for the
Al–SiC composites. The authors of [15] explained that the reason for the decrease in
densification could be that the ceramic reinforcement particles are harder than the base
soft Al matrix powder and thus during compaction will not be extruded into the pore
space.
140
Fig. 2. Fig. 3.
Fig. 2. Effect of reinforcements on the grain size. I – Al + 5% TiO2; II – Al + 5% TiO2 + 2% Gr;
III – Al + 5% TiO2 + 6% Gr; IV – Al + 5% TiO2 + 4% Gr;
� – Scherrer equation; – Williamson-Hall equation.
Fig. 3. Compressibility curves for milled powders. � – Al; – Al + 5% TiO2;
� – Al + 5% TiO2 + 2% Gr; � – Al + 5% TiO2 + 4% Gr; � – Al + 5% TiO2 + 6% Gr.
Experimental results using different compressibility equations. Al–TiO2–Gr
mixture powders were tested using the densification mathematical equation developed
by the Heckel and Balshin. The first equation of Heckel taking into account processes
occurring during pressing and this equation are applicable to metallic powders at 100…
700 MPa, where substantial rearrangement of particles occurs. Figs. 4, 5 show the re-
lationship between the relative density and applied pressure and regression equations
for Al + 0% TiO2, Al + 5% TiO2, Al + 5% TiO2 + 2% Gr, Al + 5% TiO2 + 4% Gr and
Al + 5% TiO2 + 6% Gr samples. From the Balshin densification model, we understand
that the encouragement of TiO2 and Gr amount on the linearity of the model. It is ob-
served that the deviation from the linearity of densification curves of experimental
green compacts according in Heckel model is influenced by the presence of TiO2 and
Gr reinforcing elements. The similar results were obtained by the authors in [14] who
reported for the aluminium based composites reinforced with silicon carbide particles
during compaction.
Fig. 4. Fig. 5.
Fig. 4. Densification curves according to Balshin equation. (1) = 0.1058x + 1.7145 : R2 = 0.96385;
(2) = 0.1131x + 1.6889 : R2 = 0.9586; (3) = 0.1183x + 1.6723 : R2 = 0.96536; (4) = 0.1298x +
+ 1.6214 : R2 = 0.99138; (5) = 0.1208x + 1.6547 : R2 = 0.9787 (designations as in Fig. 3).
Fig. 5. Densification curves according to Heckel equation. y = 0.00714x + 0.9249 : R2 = 0.9571;
y = 0.00573x + 0.9692 : R2 = 0.9237; y = 0.00535x + 0.9552 : R2 = 0.9127; y = 0.0.00446x +
+ 0.9225 : R2 = 0.9001; y = 0.00406x + 0.8338 : R2 = 0.9127 (designations as in Fig. 3).
141
Microstructural analysis of sintered composite. The cross section of the sinte-
red sample was prepared to reveal the uniform distribution of hard particles in alumini-
um matrix. Fig. 6a shows the scanning electron microscope image of the sintered
Al + 5% TiO2 + 6% Gr hybrid composite. It showed reasonably uniform distribution of
reinforcement particles and good interfacial integrity. The uniform distribution of hard
TiO2 and Gr reinforcement particles was achieved because of ball milling process with
suitable ball milling parameters. The size of the reinforcement particles also measured
by SEM instrument and displayed in Fig. 6b in nanometers. Fig. 7 shows the cross
sectional microstructure image of Al + 5% TiO2 + 6% Gr hybrid composite obtained
from optical microscope. Generally, the reinforcement particles were clearly identified
in the cross sectional image [16]. Here TiO2 and Gr reinforcement particles are well
distributed in aluminium matrix and they are seen as black and gray color.
Fig. 6. SEM image of sintered (a) Al + 5% TiO2 + 6% Gr hybrid composite (b),
magnified view of (a) shows the size of TiO2 particles.
Fig. 7. Optical microscope image of sintered Al + 5% TiO2 + 6% Gr hybrid composite:
a – 100 µm scale; b – 25 µm scale.
CONCLUSIONS
Aluminium hybrid composite powders have been successfully synthesized after
20 h of ball milling at the speed of 100 rpm. The grain size of the milled powders was
calculated by using Williamson Hall equation. For Al + 5% TiO2 + 6% Gr hybrid com-
posites the grain size was achieved as 224.624 nm and for the unreinforced aluminium
the grain size was 142.733 nm. The increase in grain size is due to the cold welding
and agglomeration of both hard and soft reinforcements with the ductile nature of mat-
rix materials. The lattice constant, lattice space, dislocation density, unit cell volume,
stress, and strain for all the milled composite powders were established. Adding the
hard and brittle TiO2 and soft Gr powders in the soft aluminium the compressibility
decreases, this decreasing is in agreement with the experimental compressibility curves
and the calculated (according to Heckel and Balshin model) compressibility curve, for
142
all mixtures. It is noted that the maximum densification (98.4) was obtained for the un-
reinforced aluminium at a pressure of 500 MPa. However for the same compaction
pressure the densification obtained for the Al + 5% TiO2 + 6% Gr hybrid composites is
93.2%. Scanning electron microscope analysis ensures that the uniform distribution of
reinforcement (TiO2 and Gr) particles in the Al matrix and the sizes were displayed in
the SEM images. Optical microscopic analysis reveals the formation of grain boundary
and the interfacial bonding between the reinforcements and the matrix.
РЕЗЮМЕ. Вивчали характеристики композитних порошків Al + TiO2 + Gr. Компози-
ти складу Al + 0% TiO2, Al + 5% TiO2, Al + 5% TiO2 + 2% Gr, Al + 5% TiO2 + 4% Gr та
Al + 5% TiO2 + 6% Gr отримували шляхом кульового помелу відповідних компонентів.
Для визначення розмірів зерен, параметрів кристалічної решітки, напруження, деформа-
ції, густини дислокацій та об’єму елементарної комірки використовували рентгенівський
дифракційний аналіз. Здатність до компактування Al з сумішшю порошків 5 wt.% TiO2 та
2 і 4 wt.% Gr визначали в гартованих сталевих прес-формах за тиску 100… 500 МPа. Для
розуміння особливостей компактування гібридних композитів на основі Al, зміцнених
частинками TiO2 та Gr за різних тисків, виконували експериментальні дослідження з
використанням декількох підходів. Наведено мікроструктурний аналіз композита
Al + 5% TiO2 + 6% Gr.
РЕЗЮМЕ. Изучали характеристики композитных порошков Al + TiO2 + Gr. Компо-
зиты состава Al + 0% TiO2, Al + 5% TiO2, Al + 5% TiO2 + 2% Gr, Al + 5% TiO2 + + 4% Gr и
Al + 5% TiO2 + 6% Gr получали путем шарового помола соответствующих компонентов.
Для определения размеров зерен, параметров кристаллической решетки, напряжения,
деформации, плотности дислокаций и объема элементарной ячейки использовали рентге-
новский дифракционный анализ. Способность к компактированию Al со смесью порош-
ков 5 wt.% TiO2 и 2…4 wt.% Gr определяли в закаливаемых стальных пресс-формах при
давлении 100...500 МPа. Для понимания особенностей компактирования гибридных ком-
позитов на основе Al, упрочненных частицами TiO2 та Gr при различных давлениях, про-
водили экспериментальные исследования с использованием нескольких подходов. Пред-
ставлен микроструктурный анализ композита Al + 5% TiO2 + 6% Gr.
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Received 29.01.2015
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