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  1. 42 Acta Physica Polonica A

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  1. 1 2018

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  4. 7 2015

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  1. 4 Feray Guleryuz L.

  2. 4 Füzer J.

  3. 4 Ipek R.

  4. 4 Kollár P.

  5. 4 Ozan S.

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1
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Physical Properties and Microstructural Characterization of Mechanically Alloyed and Sintered W-2wt%B₄C-xwt%C (x=0, 0.25, 0.5, 1) Composites

100%
Sönmez S., Öveçoğlu M.
Acta Physica Polonica A
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2017
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vol. 131
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issue 1
193-196
EN
Mechanical alloying processes were carried out in a Spex mixer/mill to synthesize W-2wt% B₄C-xwt% C (x=0, 0.25, 0.5, 1) powders for durations of 1 and 9 h in argon atmosphere. Mechanically alloyed powders were consolidated into green compacts by uniaxial cold press under 500 MPa and solid phase sintered at 1770°C under hydrogen and argon atmospheres for 1 h and 5 h. Effects of milling duration as well as C addition on the microstructural and mechanical properties of the sintered W-2wt% B₄C-xwt% C composite samples were investigated. The microstructural and mechanical characterizations of the sintered samples were carried out by scanning electron microscope, energy dispersive X-ray spectroscopy, X-ray diffraction, and Vickers hardness analyses. Density measurements and hardness measurements of the sintered samples were also carried out.
2
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The Characteristics of Alumina Particle Reinforced Pure Al Matrix Composite

100%
Parvin N., Rahimian M.
Acta Physica Polonica A
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2012
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vol. 121
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issue 1
108-110
EN
Al_2O_3 is widely used as the reinforcing additive in the metal matrix composites. The influence of Al_2O_3 particle size on the density, hardness, microstructure, yield stress, compression strength, and elongation of the sintered Al-Al_2O_3 composites were investigated. In the present study, 10 wt% of Al_2O_3 powder with three different particle sizes (3, 12 and 48 μm) were used in the production of the samples. Powder metallurgy technique was utilized to obtain more homogeneous Al_2O_3 distribution across the composites. The samples were cold pressed at 440 MPa, and sintered at 550C for 45 min. Results showed that the relative density of the composite was initially increased with decreasing particle size. However, it was decreased with further particle size reduction. It was also pointed out that the mechanical properties of the specimens were increased with decreasing particle size. The grain size and particle distribution homogeneity was decreased with raising the particle size.
3
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Fractographic Evaluation of Crack Initiation and Growth in Al-CNTs Nanocomposite Fabricated by Induction Melting

100%
Mansoor M., Shahid M.
Acta Physica Polonica A
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2015
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vol. 128
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issue 2B
B-276-B-278
EN
Presence of reinforcement material in the matrix plays a vital role in modifying the fracture topography besides mechanisms of deformation and strengthening of a composite. In the present study, Al-CNT composite was prepared using induction melting technique. The composite was cast into copper mold and cold rolled to ≈95% reduction in thickness. In as rolled condition, the composite exhibited a simultaneous increase in yield strength (>70%), tensile strength (>50%) and hardness (>40%). The fracture surfaces of the broken tensile specimens were studied using scanning electron microscope. It was observed that the crack initiation was occurred in the matrix followed by void link-ups for its growth. Micro cracks initiation in the matrix played a vital role to sustain the ductility of the material.
4
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Dependence of Impact Resistance of Steel Fiber Reinforced Concrete on Aggregate Origin

63%
Sezer G., Yazıcı Ş., Sezer A.
Acta Physica Polonica A
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2015
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vol. 128
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issue 2B
B-37-B-39
EN
In this study, the effect of aggregate origin on impact resistance of steel fiber reinforced concrete was investigated. Using gravel-sized limestone, basalt and natural aggregates of 20 mm of maximum size, normal and steel fiber reinforced concretes were produced. Water/cement ratio and cement dosage of concrete mixtures were 0.5 and 400 kg/m³, respectively. It should be noted that superplasticizer and steel fibers were used in concrete production. Hooked-end bundled steel fibers with l/d ratio of 65 and 1.0% fiber volume were used. After 28 days standard curing, compressive strength, split tensile strength and ultrasonic pulse velocity tests were performed on 150 × 150 × 150 mm³ cube specimens. Additionally, impact resistances of concrete specimens were determined using impact test apparatus described in ACI Committee 544. Φ150 × 300 mm³ cylinders were prepared for impact resistance tests. After 28 days curing, these specimens were cut into Φ150 × 64 mm³ dimension. Impact resistance tests were performed on these specimens. Experimental results were evaluated in terms of steel fiber presence and aggregate origin.
5
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Use of Mechanical Alloying for Production of Aluminium Matrix Composites with Non-Agglomerated Nanodiamond Reinforcing Particles

63%
Popov V., Prosviryakov A., Sagalova T., Többens D., Kiryukhantsev-Korneev P.
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vol. 126
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issue 4
1008-1011
EN
Agglomeration is the main problem that prevents large-scale implementation of nanodiamonds in the production of composites. Mechanical alloying was applied for crushing the agglomerates and to obtain uniform distribution of the primary nanodiamond particles in aluminium matrix composites. The commonly used X-ray diffraction method fails to detect non-agglomerated diamond nanoparticles 5 to 6 nm in size, if they are incorporated in a metal matrix. Synchrotron radiation was used for the identification of non-agglomerated nanodiamonds. Scanning electron microscopy and synchrotron investigation showed that mechanical alloying does not lead to transformation of the diamond structure into other allotropic forms of carbon and the nanodiamond reinforcing particles are uniformly distributed in the aluminium matrix.
6
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Effects of SiC Particle Size on Properties of Cu-SiC Metal Matrix Composites

63%
Celebi Efe G., Altinsoy I., Ipek M., Zeytin S., Bindal C.
Acta Physica Polonica A
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2012
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vol. 121
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issue 1
251-253
EN
This paper was focused on the effects of particle size and distribution on some properties of the SiC particle reinforced Cu composites. Copper powder produced by cementation method was reinforced with SiC particles having 1 and 30 μm particle size and sintered at 700°C. Scanning electron microscopy studies showed that SiC particles were dispersed in copper matrix homogeneously. The presence of Cu and SiC components in composites were verified by X-ray diffraction analysis technique. The relative densities of Cu-SiC composites determined by Archimedes' principle are ranged from 96.2% to 90.9% for SiC with 1 μm particle size, 97.0% to 95.0% for SiC with 30 μm particle size. Measured hardness of sintered compacts varied from 130 to 155 HVN for SiC having 1 μm particle size, 188 to 229 HVN for SiC having 30 μm particle size. Maximum electrical conductivity of test materials was obtained as 80.0% IACS (international annealed copper standard) for SiC with 1 μm particle size and 83.0% IACS for SiC with 30 μm particle size.
7
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Investigation of Radiation Shielding Properties of Polypropylene Fiber Reinforced Shotcrete

63%
Çakıroğlu M.
Acta Physica Polonica A
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2016
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vol. 129
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issue 4
705-706
EN
Fibre concrete has emerged in order to improve the properties of concrete and to create an economical building material. In this study, the radiation permeability of shotcrete reinforced with polypropylene fiber was investigated. For this purpose, linear attenuation coefficient was measured for shotcrete reinforced with polypropylene fiber, produced using the dry mixing process. The linear attenuation coefficients for dry mixed shotcrete have been measured at photon energies of 1173, 1332 and 662 keV. Measurements were carried out using gamma spectrometer containing NaI (Tl) detector and a Multichannel Analyzer (MCA). The linear attenuation coefficients have increased with the increasing fiber percentage for all studied gamma energies.
8
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The High Temperature Effect on Fibre Reinforced Self Compacting Lightweight Concrete Designed with Single and Hybrid Fibres

51%
Bozkurt N.
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vol. 125
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issue 2
579-583
EN
The purpose of this paper is to declare the results of investigation conducted on design of fibre reinforced self compacting lightweight concrete which has three different concrete technologies, and high temperature effect on it. For this aim, it is desired that production of new kind concrete material composed of fibre reinforced concrete, self compacting concrete and structural lightweight concrete technologies using all their better benefits. In this study, fly ash was used as a powder to reduce Portland cement consumption as well as CO_2 emission through the use of that waste material. A control self compacting concrete and 7 fibre reinforced self compacting lightweight concretes were designed applying slump flow (T50-flowing time and flowing diameter) and V-funnel tests to determine fresh concrete properties. In the design of fibre reinforced self compacting lightweight concrete, both single and hybrid fibre reinforced self compacting lightweight concrete mixes were produced using 1 macro and 1 micro steel fibres in different lengths and aspect ratios. Hybrid fibre reinforced self compacting lightweight concrete mixes were prepared using macro fibres together with micro fibre at three different percentages (50%-50%, 25%-75%, 75%-25%) by weight. After design process, cubic and prismatic concrete specimens were produced to determine hardened properties at standard concrete age. Firstly, flexural tensile and compressive strength tests were performed on the concrete specimens on 28 day. Lastly, the concrete specimens were heated up to temperatures of 200, 400, 600 and 800C then compressive strength and flexural tensile tests were performed to identify high temperature effect comparing to strength test results obtained from standard laboratory conditions. The test results showed that concrete mixes including macro fibres gave the best tensile strength properties, although they gave the worst fresh concrete properties.
9
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Microstructure and Hardness Characteristics of Al₂O₃-B₄C Particle-Reinforced Cu Matrix Composites

51%
Öksüz K., Şahin Y.
Acta Physica Polonica A
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2016
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vol. 129
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issue 4
650-652
EN
Copper is widely used in industrial applications because of its high electrical and thermal conductivity, easiness of processing and good corrosion resistance. However, copper also has some distinct limitations such as low hardness, low tensile yield strength and poor creep resistance. In this report copper matrix was reinforced with ceramics like Al₂O₃ and B₄C particles using powder metallurgy (PM) method and its microstructure was examined with SEM and EDS. The microstructure has revealed an uniform distribution of particles in the matrix and a good interface bonding between B₄C particles and the matrix. However the dispersion of Al₂O₃ particles, of larger sizes, has led to some porosity and inter-particle contacts in the composites. Therefore, hardness of B₄C particle-reinforced composites is significantly higher than that of Al₂O₃ particle-reinforced composites.
10
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Nanostructured W-Cu Electrical Contact Materials Processed by Hot Isostatic Pressing

51%
Tsakiris V., Lungu M., Enescu E., Pavelescu D., Dumitrescu G., Radulian A., Mocioi N.
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vol. 125
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issue 2
348-352
EN
Nanostructured W-Cu-Ni electrical contact materials to be used in low voltage vacuum switching contactors for nominal currents up to 630 A were developed successfully by hot isostatic pressing. W-Cu-Ni composite powder mixtures with copper content of 20 to 40 wt% and 1 wt% Ni were mechanically alloyed in Ar atmosphere by high-energy ball milling with a ratio of milling steel balls: powders mixtures of 8:1 and rotation speed of 400 rpm for 10 and 20 h. The effect of mechanical alloying on the sintering response of composite compacts was investigated. Also, the sintered contacts were characterized from the point of view of physical, microstructural, mechanical, and functional properties. The nanostructured electrical contacts presented very good sinterability and homogeneous structures with a maximum compactity degree of about 89%. The best W-Cu-Ni compositions with relative density of about 80%, chopping currents lower than 5 A, copper content lower than 40% as W-20Cu-1Ni (10 h of mechanical alloying and 20 h of mechanical alloying) and W-30%Cu-Ni (10 h of mechanical alloying) were selected to be used in vacuum contactors.
11
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Development of W-Cu-Ni Electrical Contact Materials with Enhanced Mechanical Properties by Spark Plasma Sintering Process

51%
Lungu M., Tsakiris V., Enescu E., Pătroi D., Marinescu V., Tălpeanu D., Pavelescu D., Dumitrescu G., Radulian A.
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vol. 125
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issue 2
327-330
EN
This study reports on the development of some W-Cu-Ni materials for use as electrical contacts for low voltage vacuum switching contactors for nominal currents up to 630 A. The contact materials with 85 wt% W, 12-14 wt% Cu and 1-3 wt% Ni were obtained by spark plasma sintering process in vacuum. From very finely dispersed W-Cu-Ni powder mixtures there were produced sintered electrical contact pieces that were investigated in terms of physical, microstructural, mechanical, and functional properties. The material sintered at 1200C exhibited a near fully dense structure with very low porosity and enhanced mechanical properties: hardness of maximum 480 HV1 and elastic modulus of maximum 220 GPa and low chopping current of maximum 1.77 A.
12
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"Mechanical Alloying-Compaction-Electroplating" as Technological Scheme for the Development of Nanocomposite Coatings

51%
Popov V.
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vol. 126
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issue 4
1005-1007
EN
A novel technique of producing composite electrochemical coatings with non-agglomerated nanodiamond reinforcing particles uniformly distributed in the matrix was developed. The technique is intended for coatings to be applied by transferring material from the anode to the cathode. The anode is fabricated using the mechanical alloying method that enables a composite with the uniform distribution of non-agglomerated nanoparticles to be formed.
13
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Dispersive Propagation of Ultraslow Pulses in an Atomic Bose-Einstein Condensate

51%
Tarhan D., Sefi S., Müstecaplıoğlu Ö.
Acta Physica Polonica A
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2011
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vol. 120
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issue 6
992-997
EN
One-dimensional propagation of ultraslow optical pulses in an atomic Bose-Einstein condensate taking into account the dispersion and the spatial inhomogeneity is investigated. Analytical and semi-analytical solutions of the dispersive inhomogeneous wave equation modeling the ultraslow pulse propagation are developed and compared against the standard wave equation solvers based upon Cranck-Nicholson and pseudo-spectral methods. The role of curvature of the trapping potential of the condensate on the amount of dispersion of the ultraslow pulse is pointed out.
14
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A Study of Generalized Thermoelastic Interaction in an Infinite Fibre-Reinforced Anisotropic Plate Containing a Circular Hole

51%
Abbas I., Abd-alla A.-e. n.
Acta Physica Polonica A
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2011
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vol. 119
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issue 6
814-818
EN
In the context of Lord and Shulman theory, the generalized thermoelastic theory with thermal relaxation is used to investigate the thermoelastic interaction in an infinite fibre-reinforced anisotropic plate containing a circular hole. Thermoelastic interactions are caused by a uniform step at temperature applied to the boundary of the hole which is stress-free. The problem is solved numerically using a finite element method and the numerical solutions of the non-dimensional governing partial differential equations of the problem are shown graphically. The effects of the presence and absence reinforcement on temperature, stress and displacement are studied.
15
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The Effects of Aging on the Hardness and Wear Behaviour of 2124 Al Alloy/B₄C Composites

51%
Öksüz K., Oskay K.
Acta Physica Polonica A
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2015
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vol. 127
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issue 4
1367-1369
EN
The particulate reinforced aluminum alloy matrix composites are being increasingly used for wear component applications. The influence of matrix aging treatment on wear behavior in a powder metallurgy 2124 Al-B₄C composite was investigated. The aging responses of 2124 Al-B₄C metal matrix composite (MMC) and unreinforced matrix alloy are studied and related to variations in wear resistance properties. The MMC is aged resolution treated. Accelerated aging occurs in both MMC conditions, compared with unreinforced alloy. Wear resistance and hardness were substantially higher in the reinforced alloys. The effects of the percentage of boron carbide addition on the microstructure, hardness and wear tests of the produced material are discussed. The effects of the age hardening process are also considered.
16
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Composition and Microstructure of the Al-Multilayer Graphene Composites Achieved by the Intensive Deformation

51%
Czeppe T., Korznikova E., Ozga P., Wrobel M., Litynska-Dobrzynska L., Korznikova G., Korznikov A., Czaja P., Socha R.
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vol. 126
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issue 4
921-927
EN
The paper presents results of the studies concerning aluminum-graphene composites produced with use of step technique; first mechanical alloying of Al and graphene powders and later intensive deformation by the high pressure torsion. As a result small, thin and round samples of composites, about 10 mm in diameter were achieved. For comparison similar samples not containing graphene were investigated. The X-ray diffraction, transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy were applied to study composites structures and analyze graphene content and atomic bonds. The Raman spectroscopy method suggested multilayer graphene, which could also be identified as the defected nano-graphite as a component of the composite structure as well as some small content of the aluminum carbides. The highly dispersed microstructures of aluminum matrices were identified with the transmission electron microscopy, showing difference between the samples produced with the increased number of rotations, leading to the increased deformation realized. This method revealed carbon and aluminum oxides in large amounts which is interpreted as a surface effect. This method suggested also formation of the carbon-metal and carbon-metal- oxygen atomic bonds, which might partially result from formation of the carbides.
17
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Microstructure Evolution of Tungsten-Based ODS Alloys Reinforced with the γ(Ni,~Fe) Phase by a Secondary Ball Milling Method

51%
Chen C., Zeng Y., Lee J.
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vol. 126
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issue 4
907-911
EN
In the current study, W-5Ni-2Fe-Y_2O_3 model alloys were produced using a high-energy planetary ball mill. The presence of the γ(Ni, Fe) phase is favored with respect to material properties in this alloy. Therefore, a secondary ball milling method was introduced to obtain a fine and uniformly distributed γ(Ni, Fe) phase. Phase development of mechanical alloyed powders was investigated by X-ray diffraction. The results show that the formation of the γ(Ni, Fe) phase was found after 18 h of a pre-milling procedure. A further secondary milling method produced a uniform microstructure with grain refinement. TEM results also show changes in the lattice parameters of the tungsten and γ(Ni, Fe) phase associated with the solid solubility limits in the alloy produced by secondary ball milling.
18
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Characteristics Bronze/Al_2O_3(Ni) Reinforcement Metal Matrix Composite Produced by Current Activated Sintering

51%
Uysal M., Karslioğlu R., Akbulut H., Alp A.
Acta Physica Polonica A
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2013
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vol. 123
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issue 2
235-237
EN
In this study, a bronze matrix (90 wt% Cu + 10 wt% Sn) was reinforced with Al_2O_3 particles using mechanical alloying and then produced by a subsequent rapid current sintering technique. The mechanically ball milled bronze powders were reinforced with electroless Ni coated 20 vol.% Al_2O_3 particles with three different particle sizes of 90, 70, and 50 μm. Microhardness testing, and scanning electron microscopy were used for the structural characterization of the composites. The tribological behavior of the resultant composites was tested by the ball-on-disk method at 1.0 N applied load with 0.3 m/s sliding speed for determination the wear loss and friction coefficient features against a counterface steel ball.
19
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Investigation of Dry Sliding Wear Behaviour of B_4C Particulate Reinforced Mg Matrix Composites

51%
Feray Guleryuz L., Ozan S., Uzunsoy D., Ipek R.
Acta Physica Polonica A
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2013
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vol. 123
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issue 2
488-489
EN
Currently some composite materials and related manufacturing methods especially particle reinforced magnesium matrix composites are among important research topics because of their superior properties over monolithic metals. Mg-B_4C_{p} is the commonly used composite material for fabrication of light-weight functional components. Wear behaviour of particle reinforced magnesium matrix composites play critical role for potential application in industries such as automotive and aerospace. In this study, the dry sliding wear behavior of particle reinforced magnesium matrix composites manufactured by powder metallurgy with different amount of B_4C_{p} (3,6,9 wt%) addition is investigated. Wear tests are performed on a pin-on-disk configuration against SAE 1040 steel counter body under constant load and sliding speed. The wear behaviour of particle reinforced magnesium matrix composites was evaluated as a function of B_4C_{p} amount (wt%). After the wear test, worn surface of the samples was examined by scanning electron microscopy for pointing out the wear mechanism.
20
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Wide Frequency Range AC Magnetic Properties of Fe-Based Composite Materials

51%
Kollár P., Birčáková Z., Füzer J., Füzerová J., Bureš R., Fáberová M.
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issue 5
759-761
EN
The aim of this work was to analyze the influence of resin content on contribution of the hysteresis, eddy current and anomalous losses to the total losses in the frequency range from DC to 150 kHz. The samples of composite material were prepared in the form of the ring with outer diameter of 25 mm, inner diameter of 17 mm and height approximately 3 mm and in the form of cylinder with diameter of 25 mm and height approximately 3 mm by a compaction of mixture of iron powder ASC100.29 (90 vol.%) and commercial termoset resins. The DC hysteresis losses were obtained by the measurements of DC hysteresis loops and the total power losses in the frequency range 0.4 Hz-150 kHz from AC hysteresis loops, both at maximum induction 0.05, 0.1 and 0.2 T. The magnetic properties of the composite rings were compared with the properties of the material prepared from the powder supported by Höganäs AB Sweden. By analyzing the frequency dependence of total losses of the Fe-based SMC we found out that hysteresis losses contribute to the total losses as a majority component.
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