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  1. 43 Acta Physica Polonica A

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  1. 4 Sen U.

  2. 4 Özyürek D.

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1
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Investigation of Wear Behavior of Precipitation-Strengthened Nickel-Copper Based K-500 Alloy Produced by Powder Metallurgy

100%
Esgin U., Özyürek D., Kaya H.
Acta Physica Polonica A
|
2016
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vol. 129
|
issue 4
544-547
EN
The present study investigates the effects of the ageing parameters of the precipitation-strengthened nickel-copper based K-500 alloy produced by powder metallurgy on the wear behavior of the alloy. After the cold pressing the prepared alloy powders under 600 MPa pressure, the samples were sintered under vacuum (10¯⁶ mbar) at 1150°C for 2 h and then cooled in the furnace. Produced K-500 alloy samples were taken into solution at 980°C for 1 h and quenched. Ageing process was carried out at 480°C for four different time periods (6, 8, 10, and 12 h). Aged samples were examined transmission electron microscope (TEM + EDS), X-ray diffraction (XRD), hardness and density measurements. The wear tests were carried out at 1 ms¯¹ constant sliding speed, under 40 N load and for five different sliding distances (400-2000 m). The results showed that there is γ' Ni₃(Al, Ti) inter-metallic phase coexisting with Al_{0.9}Ni_{4.22}, AlNi₃ and NiO phases. According to the hardness measurements, the highest hardness values were obtained with samples aged for 8 h. In wear tests with 2000 m sliding distance, the lowest weight loss was observed for the samples aged for 8 h.
2
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The Effects of B₄C Amount on Hardness and Wear Behaviours of 7075-B₄C Composites Produced by Powder Metallurgy Method

100%
Ay H., Özyürek D., Yıldırım M., Bostan B.
Acta Physica Polonica A
|
2016
|
vol. 129
|
issue 4
565-568
EN
In this study, the effects of B₄C amount on hardness and wear behaviours of 7075 Al-B₄C composites produced by powder metallurgy method were investigated. Within the scope of work, different amount of B₄C (3, 6, 9%) added into gas atomized 7075 Al powders. The powders were mixed in Turbula with 67 rpm for 45 min. Then the composite powders were pre-shaped by cold pressing under 600 MPa pressure. Pre-shaped samples were sintered in atmosphere controlled furnace at 580°C for 4 h. Scanning electron microscope, X-ray diffraction examinations and hardness measurements were carried out after standard metallographic processes. Wear tests were performed in a pin on type wear apparatus under 30 N with 1 m s¯¹ sliding speed, at six different sliding distances (500-3000 m). Results show that the hardness was increased with increasing of amount of B₄C. At the end of wear tests the lowest weight loss were found to 9% B₄C containing composites. In addition, it is determined that the weight loss increased with increasing sliding distance.
3
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Wear Properties of Hybrid Epoxy Composites Reinforced with Carbon/Kevlar/Glass Fabrics

100%
Kartal İ., Demirer H.
Acta Physica Polonica A
|
2017
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vol. 131
|
issue 3
559-561
EN
The aim of this study is to investigate the effect of hybridization of fabrics on wear properties of epoxy composites and to relate them to impact properties. With this aim carbon/glass/Kevlar fabrics were hybridized to reinforce epoxy composites. Epoxy composites reinforced with only carbon, glass or Kevlar fabrics were also prepared as reference composites. The wear tests were carried out using a pin-on-disk device. The wear surfaces of composite specimens were examined by scanning electron microscopy to investigate the different behavior of three distinct fabrics in the hybrid composites. The results have shown that carbon fabric reinforced epoxy composite exhibited the highest wear resistance, whereas the wear resistance of Kevlar fabric reinforced epoxy composite was the lowest. As expected, the wear resistance of hybrid composites was lower than that of only carbon fabric reinforced composites.
4
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An Investigation of the Effects of Ageing Parameters on Wear Behaviours and Electrical Conductivity of Cu-Co-Be Alloys

100%
Özyürek D., Yıldırım M., Tunçay T.
Acta Physica Polonica A
|
2016
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vol. 129
|
issue 4
559-561
EN
In this study, the effects of ageing parameters were investigated on wear behaviours and electrical conductivity of Cu-Co-Be alloy. The samples were quenched at room temperature after solution heat treated for 1 h. Then, ageing processes were applied for three different temperatures (470°C, 500°C, 530°C) and for three different ageing times (1, 2, 3 h). Microstructure examining, electrical conductivity and hardness measurements were carried out after ageing process. On the samples, which obtained the highest hardness values from hardness test (470°C), there were carried out wear tests with 1 m s¯¹ sliding speed under 30 N at four sliding distance (500-2000 m). Results clearly show that the highest hardness values were measured for samples aged at 470°C for 3 h and hardness values were decreased with increasing ageing temperature. The lowest weight loss values were evaluated for samples aged at 470°C for 3 h. The highest electrical conductivity values were measured at 500°C for 1 h aged samples.
5
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Investigation of the Effect of Different Heat Treatments on Wear Behavior of AA7075 Alloy

100%
Kalyon A., Özyürek D.
Acta Physica Polonica A
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2017
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vol. 131
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issue 1
150-152
EN
In this study, wear behavior of AA7075 alloy applied different ageing heat treatments is examined. During each ageing heat treatment, the relevant samples are processed with solid solution at 485°C for 2 h. After the quenching process, ageing processes were performed. The T6 heat treatment is applied at 120°C for 24 h. Along the re-ageing heat treatment process, samples undergone the T6 process is taken into the solid solution at 120°C once more and aged at the given temperature for 24 h. In the high temperature heat treatment process, the samples are pre-precipitated at 445°C for 30 min and then taken to ageing process at 120°C for 24 h. Wear tests are carried out at 1 m/s constant sliding speed and under 20 N load along four different sliding distances (300-1200 m). The amount of precipitation observed from the structure exhibits difference at the second phase with respect to applied ageing heat treatment. Finest precipitation particle is observed with T6 heat treatment and the coarse precipitation is with the high temperature heat treatment. Furthermore, a relationship is determined between dimension of the second phase precipitation and hardness values.
6
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Investigating the Wear Behaviours of New Type Curvilinear Gears

100%
Uzun M., Yildiz K.
Acta Physica Polonica A
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2015
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vol. 128
|
issue 2B
B-337-B-340
EN
In this study, the wear behaviors of curvilinear involute-profile gears, which were intended to be used in the industry and manufactured successfully, have been identified. For this purpose, the gears have been manufactured and attached to a FZG gear analysis bench; then, they were compared with spur gears by examining the behaviors of curvilinear involute-profile gears under different loads at different speeds, certain cycles. As a result of these analyses conducted, it has been determined that the wear behaviors of these newly manufactured curvilinear involute-profile gears are better than the behaviors of the spur gears, and in the increasing number of cycles, the curvilinear involute-profile gears had less wear than the spur gears have.
7
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The Effect of α₂-Phase (Ti₃Al) on the Wear Behavior of Titanium Alloys Added Small Amounts of Fe

100%
Simsek I., Ozyurek D.
Acta Physica Polonica A
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2017
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vol. 131
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issue 1
99-101
EN
In the present study, the effect of α₂-phase (Ti₃Al) on the wear behavior of the titanium alloys is investigated by adding different amounts of (0.3-0.5%) Fe to the Ti8Al2.5Sn and Ti5Al2.5Sn alloys, which are produced by the mechanical alloying. The pre-formed green compacts were sintered at 1200°C for one hour. The sintered samples were characterized by scanning electron microscope, X-ray diffraction, and the hardness and density measurements. The wear tests were performed under 30 N load, at four different sliding distances (400-1600 m) and with a constant speed of 1 ms¯¹. As a result of the study, it was understood that the α₂-phase (Ti₃Al) in the structure occurred at the grain boundary during the sintering process. With an increase in Fe addition to the Ti8Al2.5Sn and Ti5Al2.5Sn alloys, the density and hardness of the alloy increased as well. As a result of the wear tests, it was determined that the least weight loss occurred in Ti5Al2.5Sn alloy with a 0.5% Fe addition.
8
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The Effect of Reinforcement Ratio on the Wear Behaviour of AlB_2 Flake Reinforced Metal Matrix Composites

63%
Kayikci R., Savaş Ö., Koksal S., Demir A.
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vol. 125
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issue 2
590-592
EN
Aluminium-boride composites (Al-AlB_2) having two different volume fractions of reinforcing (AlB_2), namely 4.0 and 10.0 per cent have been produced through synthesizing boron by reaction of boron oxide (B_2O_3) with liquid aluminium. Friction and wear characteristic of the composites have been investigated under dry sliding condition and results compared with pure aluminium. The wear rate increases with normal load and sliding speed and is significantly lower with the composites when compared to that of monolithic material. The coefficient of friction increased with increasing volume fraction of AlB_2 reinforcement phase. The wear rate, however, decreased with increasing volume fraction of AlB_2.
9
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Investigation of Mechanical and Dry Sliding Wear Behaviours of AlB_2/PE Polymer Matrix Composites

63%
Savaş Ö., Ficici F., Kayikci R., Köksal S.
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vol. 125
|
issue 2
388-390
EN
In this study, mechanical and wear behaviour of polymer-boride composite (AlB_2/PE) materials produced through pressure moulding technique have been experimentally investigated. Three different composite materials that include 5 wt%, 10 wt%, and 20 wt% AlB_2 reinforcement phase were tested using pin-on-disk arrangement. Compared with the matrix, the 20 wt% AlB_2 composite shows a 71% increase in the ultimate tensile strength and the highest wear resistance.
10
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The Effect of Impact Angle of the Particle on Solid Particle Wear Properties of Basalt Base Glass-Ceramics

63%
Öztürk M., Günay U., Ercenk E., Yilmaz Ş.
Acta Physica Polonica A
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2017
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vol. 131
|
issue 1
171-173
EN
In this study, the effect of impact angle of the particles on solid particle erosive wear properties of basalt base glass-ceramics used for industrial applications was investigated. Commercial basalt glass-ceramic materials size of 20×20×3 cm was sectioned to the size of 5×5×1.2 cm. The experimental procedure was performed by using erosive wear test device with nozzle diameter of 0.78 cm. Na feldspar size of 300 μm was used as erosive media. The samples were fixed 2 cm distance from the nozzle, Na feldspar particles were sprayed by using 1.5, 3, 4 bar pressure for 20 s. The tests were repeated with 30°+45°+60°+75°+90° impact angles. The erosive wear rates were measured and the effect of particle impact angle on wear properties was determined.
11
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Characterization of CoTi Intermetallic Materials Produced by Electric Current Activated Sintering

63%
Ergin N., Ozdemir O.
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|
vol. 125
|
issue 2
399-401
EN
In the present work, the characterization and production of CoTi intermetallic materials produced by electric current activated sintering under 300 MPa uniaxial pressure in open air at 2000 A for 6 min was investigated. Cobalt powder with 10 μm size and titanium powder < 40 μm size having 99.9% and 99.5% purity, respectively, were used. The elemental powders were mixed in the stoichiometric ratio corresponding to the CoTi intermetallic, in a molar proportion of 1:1. Scanning electron microscopy and X-ray diffraction analysis were used to characterize produced samples. In microstructural examinations it was found that the sample has multi-phase microstructure. X-ray diffraction studies revealed that the phases are CoTi, CoTi_2, TiCo_2, and CoTiO_3. The relative density of test materials measured according to Archimedes' principle was 87.6%, and the microhardness of materials was about 646.74 HV_{0.1}.
12
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An Investigation on TiNi Intermetallic Produced by Electric Current Activated Sintering

63%
Ergin N., Ozdemir O.
Acta Physica Polonica A
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2013
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vol. 123
|
issue 2
248-249
EN
In this study, TiNi intermetallic compounds were produced by electric current activated sintering in open air under an uniaxial pressure of 200 MPa at a maximum of 1200 A for 10 min using Ni powder (99.8% purity, 4-7 μm), Ti powder (99.5% purity, less than 44 μm). The elemental powders were mixed in the stoichiometric ratio corresponding to the TiNi intermetallic at molar proportion of 1:1. Scanning electron microscopy and X-ray diffraction analysis were used to characterize produced samples. X-ray diffraction studies revealed that the dominant phases are TiNi, NiTi_2, Ni_3Ti, TiO, and Ni_2Ti_3. Scanning electron microscopy examinations showed a dense microstructure with very low amount of porosity. The relative density of test materials measured according to Archimedes' principle was 96.8%, and the microhardness of materials was about 773.6 ± 123 HV_{0.05}.
13
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Characterization of Ni_3Al and Ti_3Al Coatings Produced by Electric Current Activated Sintering Method

63%
Ergin N., Yoruk G., Ozdemir O.
Acta Physica Polonica A
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2013
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vol. 123
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issue 2
245-247
EN
The present study reports on Ni_3Al and Ti_3Al-based intermetallics coated on AISI 1010 steel substrate by one-step pressure assisted electric current activated sintering method. Ni, Ti, and Al elemental powders were mixed in the stoichiometric ratio corresponding to the Ni_3Al and Ti_3Al intermetallics at molar proportion of 3:1. The mixed coating powders were placed onto the steel substrate in a mold, and pressed with compressive stress of 100 MPa and then, electric current: 1100-1200 A, voltage 2.9-3.4 V was applied for 15 min during coating. As-synthesized coatings seem to have good adherence with many small porosities. The phases formed in the Ni_3Al coating layer were Ni_3Al as a major phase beside NiO and NiAl_2O_4 trace phases, which were confirmed by X-ray diffraction analysis. However, TiAl and Ti trace phases besides major Ti_3Al phase were detected in the Ti_3Al coating. The hardness of the Ni_3Al, Ti_3Al coatings and AISI 1010 substrate was approximately 321 ± 18, 445 ± 13 and 157 HV_{0.5}, respectively.
14
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Friction and Wear Behavior in Plasma Sprayed Coatings

63%
Antoszewski B.
Acta Physica Polonica A
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1996
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vol. 89
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issue 3
365-370
EN
The wear behavior and the mechanism of plasma sprayed WC12Co, Cr_{2}O_{3} and Al_{2}O_{3} coatings in sliding contact with steel bronze and carbon graphite were studied with block-on-ring arrangement. The coefficient of friction and wear rate of these coatings were measured at dry friction conditions. The worn surfaces of the coatings were examined employing the scanning electron microscope. The results obtained that the wear mechanism of coatings changes for different kinds of layers.
15
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Effect of CBC and G-POSS on Tribological Behaviour of Polyamide 6 and Short Glass Fiber Reinforced Polyamide 6 Composites

63%
Gul O., Yilmaz S., Yilmaz T.
Acta Physica Polonica A
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2015
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vol. 127
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issue 4
1121-1123
EN
In this study, effect of glycidylisobutyl oligomeric silsesquioxane (G-POSS) and 1.1'-carbonyl-bis-caprolactam (CBC) (1 wt.%) on the friction and wear performance of polyamide 6 (PA6) and short glass fiber (SGF) (10 and 20 wt.%) reinforced PA6 composites were investigated. Adhesive wear tests were carried out by using a tribometer in block-on-ring configuration (ASTM G77), in sliding conditions, without lubricants and in air. Tests were carried out at sliding speed of 1.6 m/s (511 rpm) and applied load values of 25, 50 and 75 N. Wear rate was calculated using weight loss per unit sliding distance. The results showed that, the friction force increases with the increasing load. It was found that the wear resistance of PA6 improved considerably after doping with CBC.
16
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Effects of Fuel Contamination to Marine Lubricant on Friction Behaviors between Piston Ring and Cylinder Liner

63%
Aydin Z., Savaş Ö., Parlak A., Keskin İ., Ünlügençoğlu K.
|
EN
In internal combustion engines, friction losses caused by piston ring and cylinder liner pair account for approximately 20% of total mechanical friction losses as reported in literature. A reduction in friction between piston ring and cylinder liner pair would therefore result in higher efficiency, lower fuel consumption and reduced emissions. In this study, the effects of different types of fuel which is contaminated to cylinder oil have been tested for investigating the friction behavior between piston ring and cylinder liners pair by a reciprocating tester depending on the load, revolution and temperature. The results showed that lubricant type and revolution have been found significant on friction behavior.
17
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The Effect of Low Temperature Plasma Nitriding on Wear Resistance of Ti6Al4V Alloy

63%
Gul O., Sari N., Sinmazcelik T.
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vol. 125
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issue 2
491-493
EN
The effect of low temperature plasma nitriding on wear resistance of Ti6Al4V alloy were investigated. There have been several studies to investigate the low temperature plasma nitriding on Ti6Al4V alloy. Plasma nitriding processes under gas mixture of N_2/H_2 = 3 were performed at temperature 535C for duration of 4, 8 and 12 h. Adhesive wear tests were carried out by using a tribometer in block-on-ring configuration (ASTM G77), in sliding conditions, without lubricants and in air. Surface hardness of the plasma nitrided samples were measured by a Vickers hardness tester machine. Scanning electron microscopy studies were conducted to understand the wear mechanisms involved during the adhesive wear. Wear rate was calculated using weight loss per unit sliding distance. It was found that the wear resistance and surface hardness of the alloy improved considerably after plasma nitriding process. The wear resistance of the plasma nitrided samples were higher than of the unnitrided samples. Extension of nitriding times from 4 h to 12 h in the Ti6Al4V alloy improved remerkably the wear resistance and surface hardness.
18
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The Cathodic Electrolytic Plasma Hardening of Steel and Cast Iron Based Automotive Camshafts

51%
Dayanç A., Karaca B., Kumruoğlu L.
Acta Physica Polonica A
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2017
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vol. 131
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issue 3
374-378
EN
Cathodic electrolytic plasma hardening is a novel thermochemical surface modification and hardening process, used to increase wear resistance and surface hardness of metallic components in a local area of interest. The heating efficiency is related with the plasma nozzle design, applied current and electrolyte. The nozzle design is also a critical factor for the hardening of complex shapes, such as gears and camshafts. In this work, lobes of camshafts, fabricated from several cast iron and steel grades were hardened by cathodic electrolytic plasma hardening in aqueous carbonate electrolyte, using a specific plasma nozzle. The camshafts were attached to CNC lathe for turning them in the horizontal axis. In order to optimise heating and to achieve the ideal flowing and wetting by the electrolyte of the lobe case, the ceramic ellipse-shaped nozzle outlet was designed. As a result of preliminary studies, external surface of lobes was heated and subsequently quenched by electrolyte. The hardness of processed surface was in the range of 50-60 HRc for the different camshafts. No distortion was observed on the surface of lobes. Hardness depth was measured to be from 0.1 mm to 5 mm for several lobes.
19
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The Study of Electroless Ni-P/Ni-B Duplex Coating on HVOF-Sprayed Martensitic Stainless Steel Coating

51%
Mindivan F., Mindivan H.
Acta Physica Polonica A
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2017
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vol. 131
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issue 1
64-67
EN
High velocity oxygen fuel sprayed stainless steel coatings have been widely used in various industries to repair damaged components. However, its broad application is limited due to its comparatively low hardness and inferior tribological properties. In this work, electroless Ni-P/Ni-B duplex coating with a thickness of ≈ 40 μm was deposited on surfaces of HVOF-sprayed 420 martensitic stainless steel substrate, and its structural, corrosion and tribological properties were characterized. Experimental results showed that upper Ni-B coating deposited on the surface of first Ni-P layer by duplex treatment exhibited superior hardness, wear and corrosion resistances as compared to the HVOF-sprayed 420 martensitic stainless steel coating with a thickness of about 150 μm.
20
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Dry Sliding Wear Behavior of Al_2O_3/SiC Particle Reinforced Aluminium Based MMCs Fabricated by Stir Casting Method

51%
Altınkok N., Özsert İ., Fındık F.
Acta Physica Polonica A
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2013
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vol. 124
|
issue 1
11-19
EN
Al_2O_3/SiC particulate reinforced metal matrix composites were produced by a stir casting process. The Al_2O_3/SiC powder mix was prepared by reaction of aqueous solution of aluminium sulphate, ammonium sulphate and water containing SiC particles at 1200°C. 10 wt% of this hybrid ceramic powder with different sized SiC particles was added to a liquid matrix alloy during a mechanical stirring between solidus and liquidus under inert conditions. Dry sliding wear tests were conducted with a pin-on-disk friction and wear tester. The morphologies of the worn surfaces were examined using a scanning electron microscope to observe the wear characteristics and investigate the wear mechanism. An optical microscope was used to examine the precipitations of the hybrid ceramic reinforced metal matrix composites after wear tests at room temperature under dry conditions. It was found that hybrid and bimodal particle reinforcement decreased weight loss especially when SiC powder with larger grain size was used. Microstructural examination showed that besides occurring coarse SiC particle reinforcement, a fine alumina particle reinforcement phase was observed within the aluminium matrix (A332). The improvement in wear resistance of the hybrid ceramic reinforced metal matrix composites could be attributed to the ability of the larger SiC particles to carry a greater portion of the applied load, as well as to the function of the larger SiC particles in protecting the smaller alumina particles from being gouged out during the wear process. Furthermore, the incorporation of hybrid and bimodal particles increased hardness of the composites with respect to the composite with fully small sized particles.
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