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Sample records for sliding wear behavior

  1. Sliding wear and friction behavior of zirconium alloy with heat-treated Inconel718

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.H., E-mail: kimjhoon@cnu.ac.kr [Dept. of Mechanical Design Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Park, J.M. [Dept. of Mechanical Design Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Park, J.K.; Jeon, K.L. [Nuclear Fuel Technology Department, Korea Nuclear Fuel, 1047 Daedukdae-ro, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

    2014-04-01

    In water-cooled nuclear reactors, the sliding of fuel rod can lead to severe wear and it is an important issue to sustain the structural integrity of nuclear reactor. In the present study, sliding wear behavior of zirconium alloy in dry and water environment using Pin-On-Disk sliding wear tester was investigated. Wear resistance of zirconium alloy against heat-treated Inconel718 pin was examined at room temperature. Sliding wear tests were carried out at different sliding distance, axial load and sliding speed based on ASTM (G99-05). The results of these experiments were verified with specific wear rate and coefficient of friction. The micro-mechanisms responsible for wear in zirconium alloy were identified to be microcutting and microcracking in dry environment. Moreover, micropitting and delamination were observed in water environment.

  2. Dry sliding wear behavior of heat treated hybrid metal matrix composite using Taguchi techniques

    International Nuclear Information System (INIS)

    Kiran, T.S.; Prasanna Kumar, M.; Basavarajappa, S.; Viswanatha, B.M.

    2014-01-01

    Highlights: • ZA-27 alloy is used as matrix material and reinforced with SiC and Gr particles. • Heat treatment was carried out for all specimen. • Dry sliding wear test was done on pin-on-disc apparatus by Taguchi technique. • ZA-27/9SiC–3Gr showed superior wear resistance over the base alloy. • Ceramic mixed mechanical layer on contact surface of composite was formed. - Abstract: Dry sliding wear behavior of zinc based alloy and composite reinforced with SiCp (9 wt%) and Gr (3 wt%) fabricated by stir casting method was investigated. Heat treatment (HT) and aging of the specimen were carried out, followed by water quenching. Wear behavior was evaluated using pin on disc apparatus. Taguchi technique was used to estimate the parameters affecting the wear significantly. The effect of HT was that it reduced the microcracks, residual stresses and improved the distribution of microconstituents. The influence of various parameters like applied load, sliding speed and sliding distance on wear behavior was investigated by means and analysis of variance (ANOVA). Further, correlation between the parameters was determined by multiple linear regression equation for each response. It was observed that the applied load significantly influenced the wear volume loss (WVL), followed by sliding speed implying that increase in either applied load or sliding speed increases the WVL. Whereas for composites, sliding distance showed a negative influence on wear indicating that increase in sliding distance reduces WVL due to the presence of reinforcements. The wear mechanism of the worn out specimen was analyzed using scanning electron microscopy. The analysis shows that the formation and retention of ceramic mixed mechanical layer (CMML) plays a major role in the dry sliding wear resistance

  3. Dry sliding wear behavior of epoxy composite reinforced with short palmyra fibers

    International Nuclear Information System (INIS)

    Biswal, Somen; Satapathy, Alok

    2016-01-01

    The present work explores the possibility of using palmyra fiber as a replacement for synthetic fiber in conventional polymer composites for application against wear. An attempt has been made in this work to improve the sliding wear resistance of neat epoxy by reinforcing it with short palmyra fibers (SPF). Epoxy composites with different proportions (0, 4, 8 and 12 wt. %) of SPF are fabricated by conventional hand lay-up technique. Dry sliding wear tests are performed on the composite samples using a pin-on-disc test rig as per ASTM G 99-05 standards under various operating parameters. Design of experiment approach based on Taguchi's L16 Orthogonal Arrays is used for the analysis of the wear. This parametric analysis reveals that the SPF content is the most significant factor affecting the wear process followed by the sliding velocity. The sliding wear behavior of these composites under an extensive range of test conditions is predicted by a model based on the artificial neural network (ANN). A well trained ANN has been used to predict the sliding wear response of epoxy based composites over a wide range. (paper)

  4. Dry Sliding Wear Behavior of Super Duplex Stainless Steel AISI 2507: a Statistical Approach

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    Davanageri M.

    2016-12-01

    Full Text Available The dry sliding wear behavior of heat-treated super duplex stainless steel AISI 2507 was examined by taking pin-on-disc type of wear-test rig. Independent parameters, namely applied load, sliding distance, and sliding speed, influence mainly the wear rate of super duplex stainless steel. The said material was heat treated to a temperature of 850°C for 1 hour followed by water quenching. The heat treatment was carried out to precipitate the secondary sigma phase formation. Experiments were conducted to study the influence of independent parameters set at three factor levels using the L27 orthogonal array of the Taguchi experimental design on the wear rate. Statistical significance of both individual and combined factor effects was determined for specific wear rate. Surface plots were drawn to explain the behavior of independent variables on the measured wear rate. Statistically, the models were validated using the analysis of variance test. Multiple non-linear regression equations were derived for wear rate expressed as non-linear functions of independent variables. Further, the prediction accuracy of the developed regression equation was tested with the actual experiments. The independent parameters responsible for the desired minimum wear rate were determined by using the desirability function approach. The worn-out surface characteristics obtained for the minimum wear rate was examined using the scanning electron microscope. The desired smooth surface was obtained for the determined optimal condition by desirability function approach.

  5. Wear behavior of Cu-Ag-Cr alloy wire under electrical sliding

    International Nuclear Information System (INIS)

    Jia, S.G.; Liu, P.; Ren, F.Z.; Tian, B.H.; Zheng, M.S.; Zhou, G.S.

    2005-01-01

    The wear behavior of a Cu-Ag-Cr alloy contact wire against a copper-base sintered alloy strip was investigated. Wear tests were conducted under laboratory conditions with a special sliding wear apparatus that simulated train motion under electrical current conditions. The initial microstructure of the Cu-Ag-Cr alloy contact wire was analyzed by transmission electron microscopy. Worn surfaces of the Cu-Ag-Cr alloy wire were analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The results indicate that the wear rate of the Cu-Ag-Cr wire increased with increasing electrical current and sliding. Within the studied range of electrical current, the wear rate increases with increasing electrical current and sliding speed. Compared with the Cu-Ag contact wire under the same testing conditions, the Cu-Ag-Cr alloy wire has much better wear resistance. Adhesive, abrasive, and electrical erosion wear are the dominant mechanisms during the electrical sliding processes

  6. The effects of retained austenite on dry sliding wear behavior of carburized steels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung-Jun [Research Inst. of Industrial Science and Technology, Steel Products Dept., Pohang (Korea, Republic of); Kweon, Young-Gak [Research Inst. of Industrial Science and Technology, Steel Products Dept., Pohang (Korea, Republic of)

    1996-04-01

    Ring-on-square tests on two kinds of low-alloy carburized steel which were AISI 8620 and 4140 were carried out to study the dry sliding wear behavior. The influence of different retained austenite level of 6% to 40% was evaluated while trying to eliminate other factors. Test results show that the effects of grain size and carburized steel species are negligible in dry sliding wear behavior. While the influence of retained austenite is negligible at 20 kg load condition, wear resistance is decreased at 40 kg load condition as the retained austenite level is increased from 6% to 30%. However, wear resistance is again increased above about 30% of retained austenite level at 40 kg load condition. (orig.)

  7. Sliding wear behavior of E-glass-epoxy/MWCNT composites: An experimental assessment

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    Ravindranadh Bobbili

    2016-03-01

    Full Text Available This investigation has evaluated the sliding wear properties of E-glass-epoxy/MWCNT (multiwalled carbon nanotube composite and Epoxy/MWCNT composite. Four different reinforcements (0, 0.5,1 and 1.5 wt % of MWCNTs are dispersed into an epoxy resin. Design of experiments (DOE and Analysis of variance (ANOVA are employed to understand the relationship between control factors (Percentage of reinforcement, Sliding distance, Sliding velocity and Normal load and response measures (specific wear rate and friction coefficient. The control variables such as sliding distance (300, 600, 900 and 1200 m and normal loads of 10, 15, 20 and 25 N and at sliding velocities of 1, 2, 3 and 4 m/s are chosen for this study. It is observed that that the specific wear rate and friction coefficient can be reduced by the addition of MWCNTs. Scanning electron microscopy (SEM is used to observe the worn surfaces of the samples. Compared with neat epoxy, the composites with MWCNTs showed a lower mass loss, friction coefficient and wear rate and these parameters decreased with the increase of MWCNT percentage. Microscopic investigation of worn out sample fracture surface has revealed that fiber debonding happens when the stresses at the fiber matrix interface exceeds the interfacial strength, causing the fiber to debond from the matrix. The optimum control variables have been derived to reduce both wear and friction coefficient of composites.

  8. Evaluation of dry sliding wear behavior of silicon particles reinforced aluminum matrix composites

    International Nuclear Information System (INIS)

    Sun Zhiqiang; Zhang Di; Li Guobin

    2005-01-01

    This paper reports a study on the wear property of powder metallurgy aluminum matrix composites 9Si/Al-Cu-Mg. A on rock wear-testing machine is used to evaluate the wear property of the composites, in which a GCrl5 steel ring is used as the counter face material. The wear behavior of the composites under different conditions is studied. The optical microscope and scanning electron microscope are used to analyze the worn surfaces and the subsurface of the composites in order to research the wear mechanism of the composites. Results indicate that the weight loss of the composite were lower than that of the matrix alloy

  9. Sliding friction and wear behavior of high entropy alloys at room and elevated temperatures

    Science.gov (United States)

    Kadhim, Dheyaa

    Structure-tribological property relations have been studied for five high entropy alloys (HEAs). Microhardness, room and elevated (100°C and 300°C) temperature sliding friction coefficients and wear rates were determined for five HEAs: Co0.5 Cr Cu0.5 Fe Ni1.5 Al Ti0.4; Co Cr Fe Ni Al0.25 Ti0.75; Ti V Nb Cr Al; Al0.3CoCrFeNi; and Al0.3CuCrFeNi2. Wear surfaces were characterized with scanning electron microscopy and micro-Raman spectroscopy to determine the wear mechanisms and tribochemical phases, respectively. It was determined that the two HEAs Co0.5 Cr Cu0.5 Fe Ni1.5 Al Ti0.4 and Ti V Nb Cr Al exhibit an excellent balance of high hardness, low friction coefficients and wear rates compared to 440C stainless steel, a currently used bearing steel. This was attributed to their more ductile body centered cubic (BCC) solid solution phase along with the formation of tribochemical Cr oxide and Nb oxide phases, respectively, in the wear surfaces. This study provides guidelines for fabricating novel, low-friction, and wear-resistant HEAs for potential use at room and elevated temperatures, which will help reduce energy and material losses in friction and wear applications.

  10. THE EFFECT OF VARIOUS PARAMETERS ON DRY SLIDING WEAR BEHAVIOR AND SUBSURFACE OF AGED HYBRID METAL MATRIX COMPOSITES USING TAGUCHI TECHNIQUE

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    B.M. Viswanatha

    2017-06-01

    Full Text Available The effects of applied load, sliding speed and sliding distance on the dry sliding wear behavior of aged Al-SiCp-Gr composites were investigated. The specimen were fabricated by stir-casting technique. The pin-on-disc wear testing machine was used to investigate the wear rate by design of experiments based on L27 using Taguchi technique. Sliding distance was the most important variable that influenced the wear rate followed by sliding speed and applied load. The worn out surfaces were analyzed by SEM and EDS to study the subsurface mechanism of wear. The addition of reinforcements showed improved tribological behavior of the composite than base alloy.

  11. Effect of wear parameters on dry sliding behavior of Fly Ash/SiC particles reinforced AA 2024 hybrid composites

    Science.gov (United States)

    Bhaskar Kurapati, Vijaya; Kommineni, Ravindra

    2017-09-01

    In the present work AA 2024 alloy reinforced with mixtures of SiC and Fly Ash (FA) particles of 70 µm (5, 10 and 15 wt. %) are fabricated using the stir casting method. Both reinforcements are added in equal weight proportions. The wear test specimens are prepared from both the alloy and composite castings in the dimensions of Ф 4 mm and 30 mm lengths by the wire cut EDM process. The dry sliding wear properties of the prepared composites at room temperature are estimated by pin-on-disc wear testing equipment. The wear characteristics of the composites are studied by conducting the dry sliding wear test over loads of 0.5 Kgf, 1.0 Kgf, 1.5 Kgf, a track diameter of 60 mm and sliding times of 15 min, 30 min, 45min. The experimental results shows that the wear decreases with an increase in the weight percentage of FA and SiC particles in the matrix. Additionally wear increases with an increase in load and sliding time. Further, it is found that the wear resistance of the AA2024-Hybrid composites is higher than that of the AA2024 matrix.

  12. Sliding friction and wear behaviors of surface-coated natural serpentine mineral powders as lubricant additive

    International Nuclear Information System (INIS)

    Zhang Baosen; Xu Yi; Gao Fei; Shi Peijing; Xu Binshi; Wu Yixiong

    2011-01-01

    This work aims to investigate the friction and wear properties of surface-coated natural serpentine powders (SP) suspended in diesel engine oil using an Optimal SRV oscillating friction and wear tester. The worn surface was characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). Results indicated that the additives can improve the wear resistance and decrease friction coefficient of carbon steel friction couples. The 0.5 wt% content of serpentine powders is found most efficient in reducing friction and wear at the load of 50 N. The SEM and XPS analysis results demonstrate that a tribofilm forms on the worn surface, which is responsible for the decrease in friction and wear, mainly with iron oxides, silicon oxides, graphite and organic compounds.

  13. Analysis of Microstructure and Sliding Wear Behavior of Co1.5CrFeNi1.5Ti0.5 High-Entropy Alloy

    Science.gov (United States)

    Lentzaris, K.; Poulia, A.; Georgatis, E.; Lekatou, A. G.; Karantzalis, A. E.

    2018-04-01

    Α Co1.5CrFeNi1.5Ti0.5 high-entropy alloy (HEA) of the well-known family of CoCrFeNiTi has been designed using empirical parameters. The aim of this design was the production of a HEA with fcc structure that gives ductile behavior and also high strength because of the solid solution effect. The VEC calculations (8.1) supported the fcc structure while the δ factor calculations (4.97) not being out of the limit values, advised a significant lattice distortion. From the other hand, the ΔΗ mix calculations (- 9.64 kJ/mol) gave strong indications that no intermetallic would be formed. In order to investigate its potential application, the Co1.5CrFeNi1.5Ti0.5 HEA was prepared by vacuum arc melting and a primary assessment of its surface degradation response was conducted by means of sliding wear testing using different counterbody systems for a total sliding distance of 1000 m. An effort to correlate the alloy's wear response with the microstructural characteristics was attempted. Finally, the wear behavior of the Co1.5CrFeNi1.5Ti0.5 HEA was compared with that of two commercially used wear-resistant alloys. The results obtained provided some first signs of the high-entropy alloys' better wear performance when tested under sliding conditions against a steel ball.

  14. Dry Sliding Wear Behavior of Spark Plasma Sintered Fe-Based Bulk Metallic Glass/Graphite Composites

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    Xiulin Ji

    2016-09-01

    Full Text Available Bulk metallic glass (BMG and BMG-graphite composites were fabricated using spark plasma sintering at the sintering temperature of 575 °C and holding time of 15 min. The sintered composites exhibited partial crystallization and the presence of distributed porosity and graphite particles. The effect of graphite reinforcement on the tribological properties of the BMG/graphite composites was investigated using dry ball-on-disc sliding wear tests. The reinforcement of graphite resulted in a reduction in both the wear rate and the coefficient of friction as compared to monolithic BMG samples. The wear surfaces of BMG/graphite composites showed regions of localized wear loss due to microcracking and fracture, as was also the case with the regions covered with graphite-rich protective film due to smearing of pulled off graphite particles.

  15. Dry sliding wear behavior and corrosion resistance of NiCrBSi coating deposited by activated combustion-high velocity air fuel spray process

    International Nuclear Information System (INIS)

    Liu, Shenglin; Zheng, Xueping; Geng, Gangqiang

    2010-01-01

    NiCrBSi is a Ni-based superalloy widely used to obtain high wear and corrosion resistant coatings. This Ni-based alloy coating has been deposited onto 0Cr13Ni5Mo stainless steel using the AC-HVAF technique. The structure and morphologies of the Ni-based coatings were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectrometer (EDS). The wear resistance and corrosion resistance were studied. The tribological behaviors were evaluated using a HT-600 wear test rig. The wear resistance of the Ni-based coating was shown to be higher than that of the 0Cr13Ni5Mo stainless steel because Fe 3 B, with high hardness, was distributed in the coating so the dispersion strengthening in the Ni-based coating was obvious and this increased the wear resistance of the Ni-based coating in a dry sliding wear test. Under the same conditions, the worn volume of 0Cr13Ni5Mo stainless steel was 4.1 times greater than that of the Ni-based coating. The wear mechanism is mainly fatigue wear. A series of the electrochemical tests was carried out in a 3.5 wt.% NaCl solution in order to examine the corrosion behavior. The mechanisms for corrosion resistance are discussed.

  16. Corrosive sliding wear behavior of laser clad Mo2Ni3Si/NiSi intermetallic coating

    International Nuclear Information System (INIS)

    Lu, X.D.; Wang, H.M.

    2005-01-01

    Many ternary metal silicides such as W 2 Ni 3 Si, Ti 2 Ni 3 Si and Mo 2 Ni 3 Si with the topologically closed-packed (TCP) hP12 MgZn 2 type Laves phase crystal structure are expected to have outstanding wear and corrosion resistance due to their inherent high hardness and sluggish temperature dependence and strong atomic bonds. In this paper, Mo 2 Ni 3 Si/NiSi intermetallic coating was fabricated on substrate of an austenitic stainless steel AISI321 by laser cladding using Ni-Mo-Si elemental alloy powders. Microstructure of the coating was characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDS). Wear resistance of the coating is evaluated under corrosive sliding wear test condition. Influence of corrosion solutions on the wear resistance of the coating was studied and the wear mechanism was discussed based on observations of worn surface morphology. Results showed that the laser clad Mo 2 Ni 3 Si/NiSi composite coating have a fine microstructure of Mo 2 Ni 3 Si primary dendrites and the interdendritic Mo 2 Ni 3 Si/NiSi eutectics. The coating has excellent corrosive wear resistance compared with austenitic stainless steel AISI321 under acid, alkaline and saline corrosive environments

  17. The Sliding Wear and Friction Behavior of M50-Graphene Self-Lubricating Composites Prepared by Laser Additive Manufacturing at Elevated Temperature

    Science.gov (United States)

    Liu, Xiyao; Shi, Xiaoliang; Huang, Yuchun; Deng, Xiaobin; Lu, Guanchen; Yan, Zhao; Zhou, Hongyan; Xue, Bing

    2018-03-01

    M50 steel is widely applied to manufacture aircraft bearings where service lives are mainly determined by the friction and wear behaviors. The main purpose of this study is to investigate the tribological behaviors and wear mechanisms of M50-1.5 wt.% graphene composites (MGC) prepared by laser additive manufacturing (LAM) (MGC-LAM) sliding against Si3N4 ball from 25 to 550 °C at 18 N-0.2 m/s. XRD, EPMA, FESEM, and EDS mapping were conducted to understand the major mechanisms leading to the improvement in the sliding behavior of MGC-LAM. The results indicated that MGC-LAM showed the excellent friction and wear performance at 25-550 °C for the lower friction coefficient of 0.16-0.52 and less wear rate of 6.1-9.5 × 10-7 mm3 N-1 m-1. Especially at 350 °C, MGC-LAM obtained the best tribological performance (0.16, 6.1 × 10-7mm3 N-1 m-1). It was attributed to the dense coral-like microstructure, as well as the formed surface lubricating structure which is composed of the upper uniform lubricating film with massive graphene and the underneath compacted layer.

  18. Dry Sliding Wear Behavior of A356 Alloy/Mg2Sip Functionally Graded in-situ Composites: Effect of Processing Conditions

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    S.C. Ram

    2016-09-01

    Full Text Available In present study, the effect of dry sliding wear conditions of A356 alloy/Mg2Sip functionally graded in-situ composites developed by centrifugal casting method has been studied. A pure commercial A356 alloy (Al–7.5Si–0.3Mg was selected to be the matrix of the composites and primary Mg2Sip reinforcing particles were formed by in-situ chemical reaction with an average grain size of 40-47.8 µm. The Al–(Mg2Sip functionally graded metal matrix composites (FGMMC’s were synthesized by centrifugal casting technique with radial geometry, using two different mould rotating speeds ( 1200 and 1600 rpm. The X-ray diffraction (XRD characterization technique was carried out to confirm the in-situ formed Mg2Si particles in composites. Optical microscopy examination was carried out to reveals the grain refinement of Al-rich grains due to in-situ formed Mg2Si particles. Scanning electron microscope (SEM and Energy dispersive X-ray spectroscopy (EDS techniques were carried out to reveal the distribution of phases, morphological characteristics and confirmation of primary Mg2Si particles in the matrix. The sliding wear behavior was studied using a Pin-on-Disc set-up machine with sliding wear parameters: effect of loads (N, effect of sliding distances (m and effect of Mg on wear at room temperature with a high-carbon chromium steel disc (HRC-64 as counter surfaces. A good correlation was evidenced between the dry sliding behaviour of functionally graded in-situ composites and the distribution of Mg2Si reinforcing particles. Beside the above processing conditions, the dominant wear mechanisms of functionally graded in-situ composites have been correlated with the microstructures. The hardness and wear resistance properties of these composites increase with increasing volume percent of reinforced primary Si/Mg2Si particles toward inner zone of cast cylindrical shapes. The objective of this works was to study the tribological characteristics under dry sliding

  19. Residual Stresses and Sliding Wear.

    Science.gov (United States)

    1982-05-25

    case of rolling contact, taking into account strain hardening during plastic deformation. ..-s calculations (forSAE 52100 at a hardness level of 58.5 R...can reach -800- 1000 MPa. If 033 was comparable to these values, it would indeed effect the wear rate. It is evident that an experimental deter...cc o 40 1 °2 00 I I +A ) S l~lll0 44MUK I CQ E3 e0 El 0 Uc 00 E3 (3 80 j40 c (vclq) SSHHI +ce ce mCQ ce (2E e0 4El EJ) E - 0 El 0 E0 .. t El 0 (vdNp

  20. Solidification observations and sliding wear behavior of vacuum arc melting processed Ni–Al–TiC composites

    International Nuclear Information System (INIS)

    Karantzalis, A.E.; Lekatou, A.; Tsirka, K.

    2012-01-01

    Monolithic Ni 3 Al and Ni–25 at.%Al intermetallic matrix TiC-reinforced composites were successfully produced by vacuum arc melting. TiC crystals were formed through a dissolution–reprecipitation mechanism and their final morphology is explained by means of a) Jackson's classical nucleation and growth phenomena and b) solidification rate considerations. The TiC presence altered the matrix microconstituents most likely due to specific melt–particle interactions and crystal plane epitaxial matching. TiC particles caused a significant decrease on the specific wear rate of the monolithic Ni 3 Al alloy and the possible wear mechanisms are approached by means of a) surface oxidation, b) crack/flaws formation, c) material detachment and d) debris–counter surfaces interactions. - Highlights: ► Vacuum arc melting (VAM) of Ni-Al based intermetallic matrix composite materials. ► Solidification phenomena examination. ► TiC crystal formation and growth mechanisms. ► Sliding wear examination.

  1. Heat treatment effect on the microstructure, tensile properties and dry sliding wear behavior of A356-10%B4C cast composites

    International Nuclear Information System (INIS)

    Lashgari, H.R.; Zangeneh, Sh.; Shahmir, H.; Saghafi, M.; Emamy, M.

    2010-01-01

    In present paper, an attempt was made to examine the influence of T6 heat treatment (solution treatment at 540 o C for 5 h, quenching in hot water and artificial aging at 170 o C for 8 h) on the microstructure, tensile properties and dry sliding wear behavior of A356-10%B 4 C cast composites. The composite ingots were made by stir casting process. In this work, the matrix alloy and composite were characterized by optical microscope, scanning electron microscope equipped with energy dispersive X-ray spectroscopy, tensile tests and conventional pin-on-disk experiment. The obtained results showed that in Al-B 4 C composite, T6 treatment was a dominant factor on the hardness improvement in comparison with hardness increasing due to the addition of B 4 C hard particles. In addition, T6 treatment can contribute to the strong bonding between B 4 C and matrix alloy and also it can change eutectic silicon morphology from acicular to near spherical. This case can lead to higher strength and wear properties of heat treated metal matrix composites in comparison with unheat treated state. Observation of worn surfaces indicated detachment of mechanically mixed layer which can primarily due to the delamination wear mechanism under higher applied load.

  2. Dry Sliding Friction and Wear Studies of Fly Ash Reinforced AA-6351 Metal Matrix Composites

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    M. Uthayakumar

    2013-01-01

    Full Text Available Fly ash particles are potentially used in metal matrix composites due to their low cost, low density, and availability in large quantities as waste by-products in thermal power plants. This study describes multifactor-based experiments that were applied to research and investigation on dry sliding wear system of stir-cast aluminum alloy 6351 with 5, 10, and 15 wt.% fly ash reinforced metal matrix composites (MMCs. The effects of parameters such as load, sliding speed, and percentage of fly ash on the sliding wear, specific wear rate, and friction coefficient were analyzed using Grey relational analysis on a pin-on-disc machine. Analysis of variance (ANOVA was also employed to investigate which design parameters significantly affect the wear behavior of the composite. The results showed that the applied load exerted the greatest effect on the dry sliding wear followed by the sliding velocity.

  3. Reciprocating sliding wear of Inconel 600 tubing in room temperature air

    International Nuclear Information System (INIS)

    Kim, Hun; Choi, Jong Hyun; Kim, Jun Ki; Hong, Hyun Seon; Kim, Seon Jin

    2003-01-01

    The sliding wear behavior of the material of a steam generator in a nuclear power station (Inconel 600) was investigated at room temperature. Effects of the wear parameters such as material combination, sliding distance and contact stress were examined with various mating materials including 304 austenitic stainless steel, Inconel 600 and Al-Cu alloy 2011. In the prediction of the wear volume by Archard's wear equation, the standard error range was calculated to be ±4.04x10 -9 m 3 and the reliability to be 71.9% for the combination of Inconel 600 and 304 stainless steel. The error range was considered to be relatively broad because the wear coefficient in Archard's equation was assumed to be a constant, regardless of the changes in the mechanical properties during the wear. In the present study, the sliding wear behavior turned out to be influenced by the material combination; the wear volume of 304 stainless steel did not linearly increase with the sliding distance, while that of other material combinations exhibited linear increases. Based on the experimental results, the wear coefficient was modified as a function of the sliding distance. The calculation with the modified wear equation showed that the error range narrowed down to ±2.60x10 -9 m 3 and the reliability increased to 75.3%, compared to Archard's original equation

  4. Effect of Alkyl Phenol from Cashew Nutshell Liquid on Mechanical and Dry Sliding Wear Behavior of Epoxy Resin

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    Rajesh Panda

    2015-05-01

    Full Text Available A phenalkamine made from the reaction of alkyl phenol from cashew nutshell liquid (CSNL and polyamine was added at three different weight percentages (30%, 40%, and 50% as a diglycidyl ether of bisphenol A (DGEBA epoxy hardener. This curing agent was compared to a traditional polyamine epoxy hardener. It was observed that an increase in phenalkamine concentration resulted in considerable improvement to impact strength and elongation, which ultimately translated to better wear resistance of the cured epoxy compound. Lancaster–Ratner correlations between mechanical and wear resistance properties were found to be linear. Optical microscope observations were used to understand the wear mechanisms of the cured epoxy materials.

  5. Sliding Wear and Fretting Wear of DLC-Based, Functionally Graded Nanocomposite Coatings

    Science.gov (United States)

    Miyoshi, K.; Pohlchuck, B.; Street, Kenneth W.; Zabinski, J. S.; Sanders, J. H.; Voevodin, A. a.; Wu, R. L. C.

    1999-01-01

    Improving the tribological functionality of diamondlike carbon (DLC) films--developing, good wear resistance, low friction, and high load-carrying capacity-was the aim of this investigation. Nanocomposite coatings consisting of an amorphous DLC (a-DLC) top layer and a functionally graded titanium-titanium carbon-diamondlike carbon (Ti-Ti(sub x) C(sub y)-DLC) underlayer were produced on AISI 440C stainless steel substrates by the hybrid technique of magnetron sputtering and pulsed-laser deposition. The resultant DLC films were characterized by Raman spectroscopy, scanning electron microscopy, and surface profilometry. Two types of wear experiment were conducted in this investioation: sliding friction experiments and fretting wear experiments. Unidirectional ball-on-disk sliding friction experiments were conducted to examine the wear behavior of an a-DLC/Ti-Ti(sub x) C(sub y)-DLC-coated AISI 440C stainless steel disk in sliding contact with a 6-mm-diameter AISI 440C stainless steel ball in ultrahigh vacuum, dry nitrogen, and humid air. Although the wear rates for both the coating and ball were low in all three environments, the humid air and dry nitrogen caused mild wear with burnishing, in the a-DLC top layer, and the ultrahigh vacuum caused relatively severe wear with brittle fracture in both the a-DLC top layer and the Ti-Ti(sub x) C(sub y)-DLC underlayer. For reference, amorphous hydrogenated carbon (H-DLC) films produced on a-DLC/Ti-Ti(sub x) C(sub y)-DLC nanocomposite coatings by using an ion beam were also examined in the same manner. The H-DLC films markedly reduced friction even in ultrahigh vacuum without sacrificing wear resistance. The H-DLC films behaved much like the a-DLC/Ti-Ti(sub x) C(sub y)-DLC nanocomposite coating in dry nitrogen and humid air, presenting low friction and low wear. Fretting wear experiments were conducted in humid air (approximately 50% relative humidity) at a frequency of 80 Hz and an amplitude of 75 micron on an a

  6. Dry sliding wear behavior of laser clad TiVCrAlSi high entropy alloy coatings on Ti–6Al–4V substrate

    International Nuclear Information System (INIS)

    Huang, Can; Zhang, Yongzhong; Vilar, Rui; Shen, Jianyun

    2012-01-01

    Highlights: ► TiVCrAlSi high entropy alloy coatings were obtained on Ti–6Al–4V by laser cladding. ► (Ti,V) 5 Si 3 forms because the formation is accompanied of large variation on enthalpy. ► Wear resistance of Ti–6Al–4V is improved by laser cladding with TiVCrAlSi. ► The wear mechanism is investigated. -- Abstract: Approximately equimolar ratio TiVCrAlSi high entropy alloy coatings has been deposited by laser cladding on Ti–6Al–4V alloy. The analysis of the microstructure by scanning electron microscopy (SEM) shows that the coating is metallurgically bonded to the substrate. X-ray diffraction (XRD) and energy dispersive spectrometer (EDS) analyses show that TiVCrAlSi coating is composed of precipitates of (Ti,V) 5 Si 3 dispersed in a body-centered cubic (BCC) matrix. Intermetallic compound (Ti,V) 5 Si 3 forms because the formation is accompanied by larger variation on enthalpy, which may offset the entropy term. The dry sliding wear tests show that the wear resistance of Ti–6Al–4V is improved by laser cladding with TiVCrAlSi. The enhancement of the wear resistance is explained by the presence of the hard silicide phase dispersed in a relatively ductile BCC matrix, which allows sliding wear to occur in the mild oxidative regime for a wide range of testing conditions.

  7. 3D finite element modeling of sliding wear

    Science.gov (United States)

    Buentello Hernandez, Rodolfo G.

    Wear is defined as "the removal of material volume through some mechanical process between two surfaces". There are many mechanical situations that can induce wear and each can involve many wear mechanisms. This research focuses on the mechanical wear due to dry sliding between two surfaces. Currently there is a need to identify and compare materials that would endure sliding wear under severe conditions such as high velocities. The high costs associated with the field experimentation of systems subject to high-speed sliding, has prevented the collection of the necessary data required to fully characterize this phenomena. Simulating wear through Finite Elements (FE) would enable its prediction under different scenarios and would reduce experimentation costs. In the aerospace, automotive and weapon industries such a model can aid in material selection, design and/or testing of systems subjected to wear in bearings, gears, brakes, gun barrels, slippers, locomotive wheels, or even rocket test tracks. The 3D wear model presented in this dissertation allows one to reasonably predict high-speed sliding mechanical wear between two materials. The model predictions are reasonable, when compared against those measured on a sled slipper traveling over the Holloman High Speed Tests Track. This slipper traveled a distance of 5,816 meters in 8.14 seconds and reached a maximum velocity of 1,530 m/s.

  8. Bedrock erosion by sliding wear in channelized granular flow

    Science.gov (United States)

    Hung, C. Y.; Stark, C. P.; Capart, H.; Smith, B.; Maia, H. T.; Li, L.; Reitz, M. D.

    2014-12-01

    Boundary forces generated by debris flows can be powerful enough to erode bedrock and cause considerable damage to infrastructure during runout. Bedrock wear can be separated into impact and sliding wear processes. Here we focus on sliding wear. We have conducted experiments with a 40-cm-diameter grainflow-generating rotating drum designed to simulate dry channelized debris flows. To generate sliding erosion, we placed a 20-cm-diameter bedrock plate axially on the back wall of the drum. The rotating drum was half filled with 2.3-mm-diameter grains, which formed a thin grain-avalanching layer with peak flow speed and depth close to the drum axis. The whole experimental apparatus was placed on a 100g-ton geotechnical centrifuge and, in order to scale up the stress level, spun to a range of effective gravity levels. Rates and patterns of erosion of the bedrock plate were mapped after each experiment using 3d micro-photogrammetry. High-speed video and particle tracking were employed to measure granular flow dynamics. The resulting data for granular velocities and flow geometry were used to estimate impulse exchanges and forces on the bedrock plate. To address some of the complexities of granular flow under variable gravity levels, we developed a continuum model framed around a GDR MiDi rheology. This model allowed us to scale up boundary forcing while maintaining the same granular flow regime, and helped us to understand important aspects of the flow dynamics including e.g. fluxes of momentum and kinetic energy. In order to understand the detailed processes of boundary forcing, we performed numerical simulations with a new contact dynamics model. This model confirmed key aspects of our continuum model and provided information on second-order behavior such as fluctuations in the forces acting on the wall. By combining these measurements and theoretical analyses, we have developed and calibrated a constitutive model for sliding wear that is a threshold function of

  9. Monitoring of dry sliding wear using fractal analysis

    NARCIS (Netherlands)

    Zhang, Jindang; Regtien, Paulus P.L.; Korsten, Maarten J.

    2005-01-01

    Reliable online monitoring of wear remains a challenge to tribology research as well as to the industry. This paper presents a new method for monitoring of dry sliding wear using digital imaging and fractal analysis. Fractal values, namely fractal dimension and intercept, computed from the power

  10. Sliding wear studies of sprayed chromium carbide-nichrome coatings for gas-cooled reactor applications

    International Nuclear Information System (INIS)

    Li, C.C.; Lai, G.Y.

    1978-09-01

    Chromium carbide-nichrome coatings being considered for wear protection of some critical components in high-temperature gas-cooled reactors (HTGR's) were investigated. The coatings were deposited either by the detonation gun or the plasma-arc process. Sliding wear tests were conducted on specimens in a button-on-plate arrangement with sliding velocities of 7.1 x 10 -3 and 7.9 mm/s at 816 0 C in a helium environment simulates HTGR primary coolant chemistry. The coatings containing 75 or 80 wt % chromium carbide exhibited excellent wear resistance. As the chromium carbide content decreased from either 80 or 75 to 55 wt %, with a concurrent decrease in coating hardness, wear-resistance deteriorated. The friction and wear behavior of the soft coating was similar to that of the bare metal--showing severe galling and significant amounts of wear debris. The friction characteristics of the hard coating exhibited a strong velocity dependence with high friction coefficients in low sliding velocity tests ad vice versa. Both the soft coating and bare metal showed no dependence on sliding velocity. The wear behavior observed in this study is of adhesive type, and the wear damage is believed to be controlled primarily by the delamination process

  11. Effect of magnesium content on the microstructure and dry sliding wear behavior of centrifugally cast functionally graded A356-Mg2Si in situ composites

    Science.gov (United States)

    Ram, Subhash Chandra; Chattopadhyay, K.; Chakrabarty, I.

    2018-04-01

    Functionally graded A356 alloy (Al–7.2Si–0.3Mg) –Mg2Si in situ composites have been synthesized via centrifugal casting route. Mg2Si particles tend to migrate towards the core of the tubular product by centrifugal force. The in situ formed Mg2Si particles in composites are characterized by x-ray diffraction (XRD) analysis, Energy dispersive spectrometry (EDS), Optical, Scanning Electron and Transmission Electron Microscopy. Apart from primary blocky Mg2Si particles the matrix contains other phases viz. Al-Si eutectic, pseudo-binary Al-Mg2Si eutectic and Al-Fe-Si intermetallics. Density is found to decrease and %porosity is increased with increase in volume fraction of Mg2Si. Maximum hardness was observed at the inner core region due to maximum segregation of Mg2Si particles and gradually decreases towards the outer periphery region. The dry sliding wear was evaluated with varying parameters such as normal loads (N) and sliding distances (m). A substantial increase in wear resistance at the inner core region is observed. From the worn surface characterization, the wear mechanisms have been explained.

  12. Binder extrusion of sliding wear of WC-Co alloys

    International Nuclear Information System (INIS)

    Larsen-Basse, J.

    1985-01-01

    It has previously been proposed that preferential removal of the cobalt binder is an important mechanism in the abrasive wear of cemented carbides in the WC-Co family. It is here demonstrated that binder extrusion occurs also in metal-to-metal sliding wear contacts. The wear scar generated by sliding a hardened steel ball repeatedly over a polished WC-Co surface was studied by SEM. The extruded cobalt fragments accumulate by surface defects, such as cracks caused by the sliding loaded ball, and gradual microfragmentation of the carbide grains follows. The energy required to extrude the cobalt and cause the gradual change in surface layer microstructure is provided by the frictional forces

  13. Effect of vanadium carbide on dry sliding wear behavior of powder metallurgy AISI M2 high speed steel processed by concentrated solar energy

    Energy Technology Data Exchange (ETDEWEB)

    García, C. [Materials Engineering. E.I.I., Universidad de Valladolid. C/Paseo del cauce 59, 47011 Valladolid (Spain); Romero, A. [E.T.S. Ingenieros Industriales. Instituto de Investigaciones Energéticas y Aplicaciones Industriales (INEI). Universidad de Castilla-La Mancha, Edificio Politécnico, Avda. Camilo José Cela s/n, 13071 Ciudad Real (Spain); Herranz, G., E-mail: gemma.herranz@uclm.es [E.T.S. Ingenieros Industriales. Instituto de Investigaciones Energéticas y Aplicaciones Industriales (INEI). Universidad de Castilla-La Mancha, Edificio Politécnico, Avda. Camilo José Cela s/n, 13071 Ciudad Real (Spain); Blanco, Y.; Martin, F. [Materials Engineering. E.I.I., Universidad de Valladolid. C/Paseo del cauce 59, 47011 Valladolid (Spain)

    2016-11-15

    Mixtures of AISI M2 high speed steel and vanadium carbide (3, 6 or 10 wt.%) were prepared by powder metallurgy and sintered by concentrated solar energy (CSE). Two different powerful solar furnaces were employed to sinter the parts and the results were compared with those obtained by conventional powder metallurgy using a tubular electric furnace. CSE allowed significant reduction of processing times and high heating rates. The wear resistance of compacts was studied by using rotating pin-on-disk and linearly reciprocating ball-on-flat methods. Wear mechanisms were investigated by means of scanning electron microscopy (SEM) observations and chemical inspections of the microstructures of the samples. Better wear properties than those obtained by conventional powder metallurgy were achieved. The refinement of the microstructure and the formation of carbonitrides were the reasons for this. - Highlights: •Powder metallurgy of mixtures of M2 high speed steel and VC are studied. •Some sintering is done by concentrated solar energy. •Rotating pin-on-disk and linearly reciprocating ball-on-flat methods are used. •The tribological properties and wear mechanisms, under dry sliding, are studied.

  14. Elastomers in Combined Rolling-Sliding Contact; Wear and its Underlying Mechanisms

    Science.gov (United States)

    Rowe, Kyle Gene

    Elastomeric materials, specifically rubbers, being both of a practical and scientific importance, have been the subjects of vast amounts of research spanning well over two centuries. There is currently a large effort by tire manufacturers to design new rubber compounds with lower rolling resistance, higher sliding friction, and reduced or predictable wear. At present, these efforts are primarily based on a few empirical rules and very costly trial and error testing; only a basic understanding of the mechanisms involved in the wear of elastomeric materials exists despite rigorous study. In general, the only well controlled experiments have been for simple loading and sliding schemes. The aim of this work is to characterize the tribological properties of a carbon black filled natural rubber sample. This work explores (1) its behavior in unidirectional sliding, (2) contact mechanics, (3) traction properties in combined rolling and sliding, (4) frictional heating response, and (5) wear. It was found that the friction coefficient of this material was dependent upon sliding velocity, contact pressure, and surface roughness. The high friction coefficients also lead to a bifurcation of the contact area into two different pressure regimes at sliding velocities greater than 10 mm/s . The traction response of this material in combined rolling and sliding exhibited similar behavior, being a function of the contact pressure, but not rolling velocity. The wear of this material was found to be linearly dependent upon the global slip condition and occurred preferentially on the sample. Investigations of the worn surface revealed that the most likely mechanism of wear is the degradation of surface material in a confined layer a few micrometers thick. A simple spring-mass model was developed to offer an explanation of localized wear. It was found that the coupling of system elements in the normal direction helped to shift the load from wearing elements to non-wearing ones. The

  15. Wear Behavior and Self Tribofilm Formation of Infiltration-Type TiC/FeCrWMoV Metal Ceramics Under Dry Sliding Conditions

    DEFF Research Database (Denmark)

    Wang, Yanjun; Yang, Zhenyu; Han, Liying

    2015-01-01

    infiltration furnace. The friction and wear behaviors of the composites were investigated using a pin-on-disk high temperature wear testing machine at different temperature (up to 800°C). The compositions, images and structures of worn surfaces were analyzed by means of scanning electron microscope (SEM...... PbMoO4, PbO, SnWO4, Ag2WO4 and Ag3Sn. The formation of lubrication film containing of these oxides and of intermetallic compounds was the main reason that the composites had good self-lubrication properties at high temperature. It was considered that the micro-pores on friction surface would...

  16. Friction and wear performance of bearing ball sliding against diamond-like carbon coatings

    Science.gov (United States)

    Wu, Shenjiang; Kousaka, Hiroyuki; Kar, Satyananda; Li, Dangjuan; Su, Junhong

    2017-01-01

    We have studied the tribological properties of bearing steel ball (Japan standard, SUJ2) sliding against tetrahedral amorphous carbon (ta-C) coatings and amorphous hydrogenated carbon (a-C:H) coatings. The reciprocating sliding testes are performed with ball-on-plate friction tester in ambient air condition. Analysis of friction coefficient, wear volume and microstructure in wear scar are carried out using optical microscopy, atom force morphology (AFM) and Raman spectroscopy. The results show the SUJ2 on ta-C coating has low friction coefficient (around 0.15) but high wear loss. In contrast, the low wear loss of SUJ2 on a-C:H coating with high (around 0.4) and unsteady friction coefficient. Some Fe2O3, FeO and graphitization have been found on the wear scar of SUJ2 sliding against ta-C coating. Nearly no oxide materials exist on the wear scar of SUJ2 against a-C:H coating. The mechanism and hypothesis of the wear behavior have been investigated according to the measurement results. This study will contribute to proper selection and understand the tribological performance of bearing steels against DLC coatings.

  17. Dry sliding wear of Ni alloyed austempered ductile iron

    Directory of Open Access Journals (Sweden)

    E. Akbarzadeh Chiniforush

    2016-09-01

    Full Text Available Measurements of dry sliding wear are presented for ductile irons with composition Fe-3.56C-2.67Si-0.25Mo-0.5Cu and Ni contents of 0.8 and 1.5 in wt.% with applied loads of 50, 100 and 150 N for austempering temperatures of 270, 320, and 370 °C after austenitizing at 870 °C for 120 min. The mechanical property measurements show that the grades of the ASTM 897M: 1990 Standard can be satisfied for the selected austempering conditions. The results show that wear resistance is independent of austempering temperature with an applied load of 50 N, but there is a strong dependence at higher austempering temperatures with applied loads of 100 and 150 N. Observations indicate that wear is due to subsurface fatigue with cracks nucleated at deformed graphite nodules.

  18. Surface and sliding wear behaviour of different coatings and steels

    Energy Technology Data Exchange (ETDEWEB)

    Vera-Cardenas, E.E. [Universidad Politecnica de Pachuca, Zempoala, Hidalgo (Mexico)]. E-mail: evera@upp.edu.mx; Vite-Torres, M. [Instituto Politecnico Nacional, Mexico D.F. (Mexico)]. E-mail: drmanulvite9@hotmail.com; Lewis, R. [University of Sheffield (United Kingdom)]. E-mail: roger.lewis@sheffield.ac.uk

    2012-01-15

    In this work, the sliding wear behaviour of the coatings TiN, CrN and WC/C applied on steel substrates was studied using a reciprocating wear test machine. All tests were carried out in dry conditions, at room temperature (20-23 degrees Celsius and 45% - 50% relative humidity). The average sliding velocity was 0.08 m/s and an amplitude of 2 mm was used. The applied loads were 11.76 N (Po = 1.74 GPa) and 7.84 N (Po = 1.52 GPa). Optical microscopy was used to observe the characteristics of wear scars and spalls and possible causes of their formation. The variation of the friction coefficient against the number of cycles was obtained. This was used to determine more precisely the time (number of cycles) where the coating presented the first signs of wear, in addition Energy Dispersive X-ray analysis (EDS) was performed, as well as Scanning Electron Microscopy (SEM) and hardness tests on the wear traces, which reinforced the previous observations. Thus it was possible to know the wear life of different coatings and possible causes of variation. Increasing the load was an important factor in the variation of wear life results. But it is also important to consider other factors such as surface roughness and thickness of coatings. [Spanish] En este trabajo se estudio el comportamiento en desgaste por deslizamiento de los recubrimientos de TiN, CrN y WC/C aplicados sobre sustratos de acero. Las pruebas se realizaron con una maquina reciprocante en condiciones secas a temperatura ambiente (20-23 grados centigrados y 45% - 50% de humedad relativa). Se empleo una velocidad promedio de 0.08 m/s y una amplitud de 2 mm. Las cargas aplicadas fueron de 11.76N (Po = 1.74 GPa) y de 7.84 N (Po = 1.52 GPa). Se realizo microscopia optica para observar las caracteristicas de las zonas de desgaste y sus posibles causas de formacion. Se obtuvo graficamente la variacion del coeficiente de friccion con el numero de ciclos. Estos datos se emplearon para determinar con mayor precision el

  19. Experimental Research on the Determination of the Coefficient of Sliding Wear under Iron Ore Handling Conditions

    Directory of Open Access Journals (Sweden)

    G. Chen

    2017-09-01

    Full Text Available The handling of iron ore bulk solids maintains an increasing trend due to economic development. Because iron ore particles have hard composites and irregular shapes, the bulk solids handling equipment surface can suffer from severe sliding wear. Prediction of equipment surface wear volume is beneficial to the efficient maintenance of worn areas. Archard’s equation provides a theoretical solution to predict wear volume. To use Archard’s equation, the coefficient of sliding wear must be determined. To our best knowledge, the coefficient of sliding wear for iron ore handling conditions has not yet been determined. In this research, using a pin-on-disk tribometer, the coefficients of sliding wear for both Sishen particles and mild steel are determined with regard to iron ore handling conditions. Both naturally irregular and spherical shapes of particles are used to estimate average values of wear rate. Moreover, the hardness and inner structures of Sishen particles are examined, which adds the evidence of the interpretation of wear results. It is concluded that the coefficients of sliding wear can vary largely for both Sishen particle and mild steel. The wear rate decreases from transient- to steady-state. The average coefficient of sliding wear is capable of predicting wear with respect to long distances at the steady-state. Two types of sliding friction are distinguished. In addition, it is found that the temperature rise of the friction pairs has negligible influence on wear rate.

  20. Dry sliding wear behaviour of organo-modified montmorillonite filled epoxy nanocomposites using Taguchi's techniques

    International Nuclear Information System (INIS)

    Rashmi; Renukappa, N.M.; Suresha, B.; Devarajaiah, R.M.; Shivakumar, K.N.

    2011-01-01

    Highlights: → Successful fabrication of OMMT filled epoxy nanocomposites by high-shear mixing mehod. → Systematic tribological behaviour of the nanocomposites was made using Taguchi method. → Worn surface morphologies of the samples were discussed for different wear mechanisms. → Generation of wear data for sliding/bearing parts for different industries. -- Abstract: The aim of the research article is to study the dry sliding wear behaviour of epoxy with different wt.% of organo-modified montmorillonite (OMMT) filled nanocomposites. An orthogonal array (L 9 ) was used to investigate the influence of tribological parameters. The results indicate that the sliding distance emerges as the most significant factor affecting wear rate of epoxy nanocomposites. Experimental results showed that the inclusion of 5 wt.% OMMT nanofiller increased the wear resistance of the epoxy nanocomposite significantly. Furthermore, the worn surfaces of the samples were analyzed by scanning electron microscopy (SEM) to study the wear mechanisms and to correlate them with the wear test results.

  1. Experimental Study of the Hygrothermal Effect on Wear Behavior of Composite Materials

    OpenAIRE

    Fadhel Abbas. Abdulla; Katea L. Hamid

    2017-01-01

    The hygrothermal effect on the wear behavior of composite material (fiberglass and polyester resin vf=40%) was investigated experimentally in this work. The study includes manufacturing of test device (pin on disc) according to ASTM G 99. In order to study the hygrothermal effect on wear behavior of composite materials the hygrothermal chamber was manufactured. The experimental results show that the wear of glass fiber/polyester increased with increasing the load, sliding speed and sliding di...

  2. The effects of various reinforcements on dry sliding wear behaviour of AA 6061 nanocomposites

    International Nuclear Information System (INIS)

    Jeyasimman, D.; Narayanasamy, R.; Ponalagusamy, R.; Anandakrishnan, V.; Kamaraj, M.

    2014-01-01

    Highlights: • Wear and friction coefficient of nanocomposites were investigated. • The worn surface morphologies of nanocomposites were analysed. • The wear rate was increased with increasing load and sliding velocity. • The friction coefficient was decreased with increasing load and sliding velocity. - Abstract: The present work aims to investigate the dry sliding wear behaviour of AA 6061 nanocomposites reinforced with various nanolevel reinforcements, such as titanium carbide (TiC), gamma phase alumina (γ-Al 2 O 3 ) and hybrid (TiC + Al 2 O 3 ) nanoparticles with two weight percentages (wt.%) prepared by 30 h of mechanical alloying (MA). The tests were performed using a pin-on-disk wear tester by sliding these pin specimens at sliding speeds of 0.6, 0.9 and 1.2 m/s against an oil-hardened non-shrinking (OHNS) steel disk at room temperature. Wear tests were conducted for normal loads of 5, 7 and 10 N at different sliding speeds at room temperature. The variations of the friction coefficient and the wear rate with the sliding distances (500 m, 1000 m and 1600 m) for different normal loads and sliding velocities were plotted and investigated. To observe the wear characteristics and to investigate the wear mechanism, the morphologies of the worn surfaces were analysed using a scanning electron microscope (SEM). The formation of an oxide layer on the worn surface was examined by energy dispersive spectroscopy (EDS). The wear rate was found to increase with the load and sliding velocity for all prepared nanocomposites. Hybrid (TiC + Al 2 O 3 ) reinforced AA 6061 nanocomposites had lower wear rates and friction coefficients compared with TiC and Al 2 O 3 reinforced AA 6061 nanocomposites

  3. Effect of bagasse ash reinforcement on dry sliding wear behaviour of polymer matrix composites

    International Nuclear Information System (INIS)

    Aigbodion, V.S.; Hassan, S.B.; Agunsoye, J.O.

    2012-01-01

    Highlights: → The influence of wear parameters on the wear rate of RLDPE were investigated. → The predicted wear rate of the RLDPE and it composites were found to lie close to that experimentally observed ones. → The results showed that the addition of bagasse ash as filler materials in RLDPE composites increase the wear resistance. -- Abstract: The tribological behaviour of recycled low density polyethylene (RLDPE) polymer composites with bagasse ash particles as a reinforcement was studied using a pin-on-disc wear rig under dry sliding conditions. The influence of wear parameters like, applied load, sliding speed, sliding distance and percentage of bagasse ash fillers, on the wear rate were investigated. A plan of experiments was performed to acquire data in a controlled way. Scanning electron microscope was used to analyse the worn surface of the samples. Linear regression equation and analysis of variance (ANOVA) were employed to investigate the influence of process parameters on the wear rate of the samples. The predicted wear rate of the RLDPE and it composites were found to lie close to that experimentally observed ones. The confirmation of the experiments conducted using ANOVA to verify the optimal testing parameters show that sliding speed and applied load had significant effect on the wear rate. The results showed that the addition of bagasse ash as filler materials in RLDPE composites increase the wear resistance of the composite greatly.

  4. Lubricated sliding wear behaviour of Ni-P-W multilayered alloy coatings produced by pulse plating

    DEFF Research Database (Denmark)

    Panagopoulos, C. N.; Papachristos, V. D.; Christoffersen, Lasse

    2000-01-01

    The lubricated sliding wear behaviour of Ni-P-W multilayered alloy coatings sliding against hardened steel discs was studied, in a pin-on-disc set-up. The multilayered coatings had been deposited on mild steel pins by pulse plating and they consisted of ternary Ni-P-W layers of high and low W con...... lubrication regimes. The wear mechanisms in each lubrication regime were studied and in mixed lubrication regime, the effect of normal load and sliding speed on wear volume and friction coefficient was also studied. (C) 2000 Elsevier Science S.A. All rights reserved....

  5. Friction and wear behavior of Colmonoy and Stellite alloys in sodium environment

    International Nuclear Information System (INIS)

    Kanoh, S.; Mizobuchi, S.; Atsumo, H.

    1976-01-01

    A description is given of a series of experiments in sodium environment for the research and development of friction and wear resistant material used for the sliding components of sodium cooled fast breeder reactor. The study relates to the friction and wear characteristics of nickel-base alloy, Colmonoy, and cobalt-base alloy, Stellite, with respect to temperature, load, sliding velocity, sliding mode, and sodium flushing. The friction behavior of these alloys in sodium is compared with that in argon

  6. Synthesis and Study on Effect of Parameters on Dry Sliding Wear Characteristics of AL-SI Alloys

    Directory of Open Access Journals (Sweden)

    Francis Uchenna OZIOKO

    2012-08-01

    Full Text Available The effect of parameters on dry sliding wear characteristics of Al-Si alloys was studied. Aluminium-silicon alloys containing 7%, 12% and 14% weight of silicon were synthesized using casting method. Dry sliding wear characteristics of sample were studied against a hardened carbon steel (Fe-2.3%Cr-0.9%C using a pin-on-disc. Observations were recorded keeping two parameters (sliding distance, sliding speed and load constant against wear at room temperature. Microstructural characterization was done using optical microscope (OM and scanning electron microscope (SEM. Hardness and wear characteristics of different samples have shown near uniform behaviour. The wear rate decreased when the percentage of silicon increases. Wear was observed to increase at higher applied load, higher sliding speed and higher sliding distance. The wear characteristics of Al-14%Si was observed superior to those of Al-7%Si and Al-12%Si due to the degree of refinement of their eutectic silicon.

  7. Experimental Study of the Hygrothermal Effect on Wear Behavior of Composite Materials

    Directory of Open Access Journals (Sweden)

    Fadhel Abbas. Abdulla

    2017-07-01

    Full Text Available The hygrothermal effect on the wear behavior of composite material (fiberglass and polyester resin vf=40% was investigated experimentally in this work. The study includes manufacturing of test device (pin on disc according to ASTM G 99. In order to study the hygrothermal effect on wear behavior of composite materials the hygrothermal chamber was manufactured. The experimental results show that the wear of glass fiber/polyester increased with increasing the load, sliding speed and sliding distance. The load and sliding distance were more effective on the wear of the composite rather than sliding speed. Also, it has been revealed that, the hygrothermal is considerable effect that, the wear rate of glass fiber/polyester without hygrothermal effect is lower than wear with hygrothermal effect. Applied load is the wear factor that has the highest physical influence on the wear of composites materials than other wear factors. Also, the wear of glass fiber/polyester without hygrothermal effect is lower than wear with hygrothermal effect.

  8. Effect of distribution of striated laser hardening tracks on dry sliding wear resistance of biomimetic surface

    Science.gov (United States)

    Su, Wei; Zhou, Ti; Zhang, Peng; Zhou, Hong; Li, Hui

    2018-01-01

    Some biological surfaces were proved to have excellent anti-wear performance. Being inspired, Nd:YAG pulsed laser was used to create striated biomimetic laser hardening tracks on medium carbon steel samples. Dry sliding wear tests biomimetic samples were performed to investigate specific influence of distribution of laser hardening tracks on sliding wear resistance of biomimetic samples. After comparing wear weight loss of biomimetic samples, quenched sample and untreated sample, it can be suggested that the sample covered with dense laser tracks (3.5 mm spacing) has lower wear weight loss than the one covered with sparse laser tracks (4.5 mm spacing); samples distributed with only dense laser tracks or sparse laser tracks (even distribution) were proved to have better wear resistance than samples distributed with both dense and sparse tracks (uneven distribution). Wear mechanisms indicate that laser track and exposed substrate of biomimetic sample can be regarded as hard zone and soft zone respectively. Inconsecutive striated hard regions, on the one hand, can disperse load into small branches, on the other hand, will hinder sliding abrasives during wear. Soft regions with small range are beneficial in consuming mechanical energy and storing lubricative oxides, however, soft zone with large width (>0.5 mm) will be harmful to abrasion resistance of biomimetic sample because damages and material loss are more obvious on surface of soft phase. As for the reason why samples with even distributed bionic laser tracks have better wear resistance, it can be explained by the fact that even distributed laser hardening tracks can inhibit severe worn of local regions, thus sliding process can be more stable and wear extent can be alleviated as well.

  9. The effect of Al–8B grain refiner and heat treatment conditions on the microstructure, mechanical properties and dry sliding wear behavior of an Al–12Zn–3Mg–2.5Cu aluminum alloy

    International Nuclear Information System (INIS)

    Alipour, M.; Azarbarmas, M.; Heydari, F.; Hoghoughi, M.; Alidoost, M.; Emamy, M.

    2012-01-01

    Highlights: ► The effect of Al–8B on the properties of aluminum alloy was studied. ► Al–8B is an effective in reducing the grain and reagent fine microstructure. ► Al–8B is an effective in optimization of properties. -- Abstract: In this study the effect of Al–8B grain refiner on the structural and properties of Al–12Zn–3Mg–2.5Cu aluminum alloy were investigated. The optimum amount for B containing grain refiner was selected as 3.75 wt.%. The results showed that B containing grain refiner is more effective in reducing average grain size of the alloy. T6 heat treatment was applied for all specimens before tensile testing. Significant improvements in mechanical properties were obtained with the addition of grain refiner combined with T6 heat treatment. After the heat treatment, the average tensile strength increased from 479 MPa to 537 MPa for sample refined with 3.75 wt.% Al–8B. The fractography of the fractured faces and microstructure evolution was characterized by scanning electron microscopy and optical microscopy. Dry sliding wear performance of the alloy was examined in normal atmospheric conditions. The experimental results showed that the T6 heat treatment considerably improved the resistance of Al–12Zn–3Mg–2.5Cu aluminum alloy to the dry sliding wear.

  10. Role of carbon nanotubes (CNTs) in improving wear properties of polypropylene (PP) in dry sliding condition

    International Nuclear Information System (INIS)

    Ashok Gandhi, R.; Palanikumar, K.; Ragunath, B.K.; Paulo Davim, J.

    2013-01-01

    Highlights: ► Role of carbon nanotubes (CNTs) on wear behaviour of polypropylene (PP) is evaluated. ► Effect of applied pressure and composition against a steel counter face is investigated. ► Microstructure and worn surfaces of samples are observed by scanning electron microscope. ► The wear phenomenon has been discussed based on wear losses and worn surfaces. ► The coefficient of friction (μ) and sliding time for PP and PP/CNT blend is investigated. - Abstract: Polymers are widely used for sliding couples against metals and other materials. Polypropylene is a polymer used in variety of applications includes packaging, laboratory equipments, automotive components, etc. Polypropylene is often desirable automotive material due to its low cost, colorability, chemical resistance and UV stability. In addition the range of potential polypropylene uses is nearly unlimited through the use of modifiers, additives and fillers. In the present work, the sliding wear of polypropylene (PP) and carbon nanotube (CNT) blends are evaluated as a function of applied load and composition against a steel counter face in dry condition. The addition of CNT in PP in wear performance is investigated and presented in detail. Microstructure and worn surfaces of samples were observed by scanning electron microscope. The wear phenomenon has been discussed based on wear losses and worn surfaces

  11. The effect of graphene content and sliding speed on the wear mechanism of nickel–graphene nanocomposites

    International Nuclear Information System (INIS)

    Algul, H.; Tokur, M.; Ozcan, S.; Uysal, M.; Cetinkaya, T.; Akbulut, H.; Alp, A.

    2015-01-01

    Graphical abstract: - Highlights: • Graphene reinforced nickel matrix composites were produced by pulse electroplating method at a constant current density of 5 A/dm"2. • Incorporating graphene refines the grain size and changes the microstructure of the coating. • Incorporating graphene greatly improves the friction reduction and wear resistance of the coating. • The nickel/graphene composite coating containing 500 mg/L graphene in the electrolyte showed the best results. - Abstract: Nickel–graphene metal matrix composite coatings were fabricated by pulse electrodeposition technique from a Watt's type electrolyte. Effect of the graphene concentration in the electrolyte on the microstructure, microhardness, tribological features of nanocomposite coatings were evaluated in details. Microhardness of the composite coating was measured using a Vicker's microhardness indenter. The surfaces of the samples were characterized by scanning electron microscopy (SEM). Raman spectroscopy, EDS and XRD analysis were used to determine chemical composition and structure of composite coatings. The tribological behavior of the resultant composite coating was tested by a reciprocating ball-on disk method at constant load but varying sliding speeds for determination the wear loss and friction coefficient features against a counterface. The wear and friction variations of the electrodeposited nickel graphene nanocomposite coatings sliding against an M50 steel balls were carried out on a CSM Instrument. The friction and wear properties of the coatings were examined without any lubrication at room temperature in the ambient air. The change in wear mechanisms by changing graphene nanosheets content was also comprehensively studied.

  12. Sand Particles Impact on the Tribological Behavior of Sliding Contact

    Directory of Open Access Journals (Sweden)

    Aldajah Saud

    2016-01-01

    Full Text Available Lubricant contaminants cause severe problems to machines. Substantial research has been conducted to study the impact of such contaminates on the tribological performance of lubricated contacts. The primary goal of such studies is to find solutions to avoid the dirtiest cause of damaging machines’ parts and to reduce energy consumption and maintenance costs. The current study investigates the tribological behavior of contaminated lubricated contacts; the contaminants considered in this research are sand particles. The effect of the sand particles concentration levels on friction and wear of a tribological system under sliding contact was studied. Three different concentration levels were tested; 5%, 10% and 15%.The experimental program was carried out using an in-house built ball on disc machine at room temperature, constant normal load, constant speed, constant running time and constant travelling distance. Results showed that both friction coefficient and wear volume of the contacting surfaces are dependent on the concentration level of the sand particles. Both friction coefficient and wear volume increased by increasing the sand particles concentration. SEM was utilized to study the wear mechanisms of the contacting surfaces, it was found that the dominant wear mechanism in all cases was abrasive wear.

  13. Effect of Lubrication on Sliding Wear of Red Mud Particulate Reinforced Aluminium Alloy 6061

    OpenAIRE

    N. Panwar; R.P. Poonia; G. Singh; R. Dabral; A. Chauhan

    2017-01-01

    In present study, Red mud, an industrial waste, has been utilized as a reinforcement material to fabricate Aluminium 6061 matrix based metal matrix composite. Taguchi L18 orthogonal array has been employed for fabrication of composite castings and for conducting the tribological experimentation. ANOVA analysis has been applied to examine the effect of individual parameters such as sliding condition: dry and wet, reinforcement weight fraction, load, speed, and sliding distance on specific wear...

  14. Severe wear behaviour of alumina balls sliding against diamond

    Indian Academy of Sciences (India)

    Wear and friction data were recorded for microwave plasma chemical vapour deposition (MWCVD) grown PCD coatings of four different types, out of which two ... CSIR–Central Glass & Ceramic Research Institute, Kolkata 700032, India; Department of Chemistry, National Institute of Technology, Durgapur 713209, India ...

  15. Cerium Addition Improved the Dry Sliding Wear Resistance of Surface Welding AZ91 Alloy

    Directory of Open Access Journals (Sweden)

    Qingqiang Chen

    2018-02-01

    Full Text Available In this study, the effects of cerium (Ce addition on the friction and wear properties of surface welding AZ91 magnesium alloys were evaluated by pin-on-disk dry sliding friction and wear tests at normal temperature. The results show that both the friction coefficient and wear rate of surfacing magnesium alloys decreased with the decrease in load and increase in sliding speed. The surfacing AZ91 alloy with 1.5% Ce had the lowest friction coefficient and wear rate. The alloy without Ce had the worst wear resistance, mainly because it contained a lot of irregularly shaped and coarse β-Mg17Al12 phases. During friction, the β phase readily caused stress concentration and thus formed cracks at the interface between β phase and α-Mg matrix. The addition of Ce reduced the size and amount of Mg17Al12, while generating Al4Ce phase with a higher thermal stability. The Al-Ce phase could hinder the grain-boundary sliding and migration and reduced the degree of plastic deformation of subsurface metal. Scanning electron microscopy observation showed that the surfacing AZ91 alloy with 1.5% Ce had a total of four types of wear mechanism: abrasion, oxidation, and severe plastic deformation were the primary mechanisms; delamination was the secondary mechanism.

  16. Standard test method for ranking resistance of materials to sliding wear using block-on-ring wear test

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers laboratory procedures for determining the resistance of materials to sliding wear. The test utilizes a block-on-ring friction and wear testing machine to rank pairs of materials according to their sliding wear characteristics under various conditions. 1.2 An important attribute of this test is that it is very flexible. Any material that can be fabricated into, or applied to, blocks and rings can be tested. Thus, the potential materials combinations are endless. However, the interlaboratory testing has been limited to metals. In addition, the test can be run with various lubricants, liquids, or gaseous atmospheres, as desired, to simulate service conditions. Rotational speed and load can also be varied to better correspond to service requirements. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. Wear test results are reported as the volume loss in cubic millimetres for both the block and ring. Materials...

  17. The effects of induction hardening on wear properties of AISI 4140 steel in dry sliding conditions

    International Nuclear Information System (INIS)

    Totik, Y.; Sadeler, R.; Altun, H.; Gavgali, M.

    2002-01-01

    Wear behaviour of induction hardened AISI 4140 steel was evaluated under dry sliding conditions. Specimens were induction hardened at 1000 Hz for 6, 10, 14, 18, 27 s, respectively, in the inductor which was a three-turn coil with a coupling distance of 2.8 mm. Normalised and induction hardened specimens were fully characterised before and after the wear testing using hardness, profilometer, scanning electron microscopy and X-ray diffraction. The wear tests using a pin-on-disc machine showed that the induction hardening treatments improved the wear behaviour of AISI 4140 steel specimens compared to normalised AISI 4140 steel as a result of residual stresses and hardened surfaces. The wear coefficients in normalised specimens are greater than that in the induction hardened samples. The lowest coefficient of the friction was obtained in specimens induction-hardened at 875 deg. C for 27 s

  18. The effects of induction hardening on wear properties of AISI 4140 steel in dry sliding conditions

    Energy Technology Data Exchange (ETDEWEB)

    Totik, Y.; Sadeler, R.; Altun, H.; Gavgali, M

    2002-02-15

    Wear behaviour of induction hardened AISI 4140 steel was evaluated under dry sliding conditions. Specimens were induction hardened at 1000 Hz for 6, 10, 14, 18, 27 s, respectively, in the inductor which was a three-turn coil with a coupling distance of 2.8 mm. Normalised and induction hardened specimens were fully characterised before and after the wear testing using hardness, profilometer, scanning electron microscopy and X-ray diffraction. The wear tests using a pin-on-disc machine showed that the induction hardening treatments improved the wear behaviour of AISI 4140 steel specimens compared to normalised AISI 4140 steel as a result of residual stresses and hardened surfaces. The wear coefficients in normalised specimens are greater than that in the induction hardened samples. The lowest coefficient of the friction was obtained in specimens induction-hardened at 875 deg. C for 27 s.

  19. Dry sliding behavior of aluminum alloy 8011 with 12% fly ash composites

    Science.gov (United States)

    Magibalan, S.; Senthilkumar, P.; Palanivelu, R.; Senthilkumar, C.; Shivasankaran, N.; Prabu, M.

    2018-05-01

    This research focused on the fabrication of aluminum alloy 8011 with 12% fly ash (FA) composite (AA8011%–12% FA) using the stir casting method. A three-level central composite design experiment was developed using response surface methodology with various parameters such as load, time, and sliding velocity varied in the range of 5 to 15 N, 5 to 15 min, and 1.5 to 4.5 m.s‑1, respectively. Dry sliding wear tests were performed as per the experimental design using a pin on disc at room temperature. The obtained regression result indicated that the developed model performed well in relating the wear process parameters and predicted the wear behavior of the composite. The surface plot showed that the wear rate increases with increase in load, time, and sliding velocity. Hardness was evaluated by Vickers hardness testing machine. Moreover, the surface morphology of the worn-out composite was examined using a scanning electron microscope.

  20. Role of PET in improving wear properties of PP in dry sliding condition

    Indian Academy of Sciences (India)

    Unknown

    ... blends were studied using scanning elec- tron microscopy. Sliding wear properties of these blends have been determined and studied for various blend com- positions. 2. Materials and methods. 2.1 Materials. Isotactic polypropylene PP (density 0⋅91 g/cc, grade SRM. 100 N) was obtained from M/s Indian Petrochemicals.

  1. Dry sliding wear behaviour of Al-12Si-4Mg alloy with cerium addition

    International Nuclear Information System (INIS)

    Anasyida, A.S.; Daud, A.R.; Ghazali, M.J.

    2010-01-01

    The purpose of this work is to understand the effect of cerium addition on wear resistance behaviour of as-cast alloys. Al-12Si-4 Mg alloys with 1-5 wt% cerium addition were prepared using the casting technique. A sliding wear test was carried out under applied loads of 10 N, 30 N and 50 N at a fixed sliding speed of 1 m/s using a pin-on-disc configuration. The wear test was conducted in dry conditions at room temperature of ∼25 o C. Detailed analysis of the microstructure, worn surface, collected debris and microhardness was undertaken in order to investigate the differences between the as-cast alloys with different levels of cerium addition. The addition of 1-5 wt% cerium was found to lead to the precipitation of intermetallic phases (Al-Ce), resulting a needle-like structures. Increasing cerium content up to 2 wt% improved both wear resistance and microhardness of as-cast alloys. Addition of more than 2 wt% cerium, however, led to a decrease in microhardness, resulting in lower wear resistance of the alloys. Moderate wear was observed at all loads, with specific wear rates (K') ranging from 6.82 x 10 -5 with 2 wt% Ce at applied load of 50 N to 21.48 x 10 -5 mm 3 /N m without added Ce at an applied load of 10 N. Based on K' ranges, the as-cast alloys exhibited moderate wear regimes, and the mechanism of wear is a combination of abrasion and adhesion. Alloy containing 2 wt% Ce, with the highest hardness and lowest K' value, showed the greatest wear resistance.

  2. Effect of Lubrication on Sliding Wear of Red Mud Particulate Reinforced Aluminium Alloy 6061

    Directory of Open Access Journals (Sweden)

    N. Panwar

    2017-09-01

    Full Text Available In present study, Red mud, an industrial waste, has been utilized as a reinforcement material to fabricate Aluminium 6061 matrix based metal matrix composite. Taguchi L18 orthogonal array has been employed for fabrication of composite castings and for conducting the tribological experimentation. ANOVA analysis has been applied to examine the effect of individual parameters such as sliding condition: dry and wet, reinforcement weight fraction, load, speed, and sliding distance on specific wear rate obtained experimentally. It has been found that tensile strength and impact energy increases while elongation decreases, with increasing weight fraction and decrease in particle size of red mud. The percentage contribution of the effect of factors on SWR is Sliding condition (73.17, speed (7.84, percentage reinforcement (7.35, load (5.75, sliding distance (2.24, and particle size (1.25. It has also been observed that specific wear rate is very low in wet condition. However, it decreases with increase in weight fraction of reinforcement, decrease in load and sliding speed. Al6061/red mud metal matrix composites have shown reasonable strength and wear resistance. The use of red mud in Aluminium composite provides the solution for disposal of red mud and can possibly become an economic replacement of Aluminium and its alloys.

  3. Site specific SEM/FIB/TEM for analysis of lubricated sliding wear of aluminium alloy composites

    International Nuclear Information System (INIS)

    Walker, J C; Jones, H; Rainforth, W M

    2006-01-01

    Although extensive research has been undertaken into the dry sliding wear of aluminium alloys, only limited work has been reported on lubricated wear. In this paper, the lubricated sliding wear of some powder derived aluminium alloy composites is reported. Stereo pairs of the worn surface were obtained in the SEM and digitally reconstructed to give an accurate projection of the surface topography. Analysis of the average surface roughness (R a ) along chosen sections provided quantitative information about the wear mechanism. Following this, dual beam focused ion beam (FIB) was undertaken to further explore the features revealed by the SEM surface reconstructions, with TEM sections removed from selected regions. Surface deformation was confined to a narrow layer, typically 1μm thick. Subgrain size within the subsurface layer was comparable to that found in dry sliding wear tests. Reinforcement fracture occurred in the surface particles only. The resultant fragments were often incorporated back into the surface following detachment, such that the total volume fraction reinforcement at the surface was greater than in the bulk. Thus, the dynamic surface topography was a result of three factors: surface deformation, local detachment of reinforcement and re-incorporation of the fragments back into the surface

  4. Wear mechanisms and friction parameters for sliding wear of micron-scale polysilicon sidewalls

    NARCIS (Netherlands)

    Alsem, D. H.; van der Hulst, R.; Stach, E. A.; Dugger, M. T.; De Hosson, J. Th. M.; Ritchie, R. O.

    As tribological properties are critical factors in the reliability of silicon-based microelectromechanical systems, it is important to understand what governs wear and friction. Average dynamic friction, wear volumes and morphology have been studied for polysilicon devices fabricated using the

  5. The influence of reciprocating sliding wear on the oxidation behaviour of Fe-12Cr steel

    International Nuclear Information System (INIS)

    Smith, A.F.

    1989-01-01

    Medium-chromium ferritic alloys are used extensively in advanced gas cooled reactors (AGRs). Under certain conditions these alloys can undergo breakaway oxidation in which the rate-limiting step is located at the oxide/metal interface rather than the more usual gas/oxide interface; this results in linear oxidation kinetics. Repeated removal of oxide layers can expose chromium-depleted metal to the oxidizing gas and promote nucleation of breakaway oxidation. The question has been addressed as to whether high temperature sliding wear processes can also disrupt the surface so as to make the material potentially susceptible to breakaway oxidation. High temperature reciprocating wear tests of Fe-12Cr material in both low and high pressure reactor gas have been carried out. As expected, compact adhesive load-bearing oxide and mixed oxide/metal beds form in wear regions. These contacting features wear at very low rates of less than 10 -16 m 3 (Nm) -1 . Preformed oxides wear at sufficiently low rates at high temperature as to preclude the possibility of exposure of the underlying metal to the reactor gas. It is thus unlikely that sliding wear processes will accelerate the tendency for initiation of breakaway oxidation. (author)

  6. Standard test method for ranking resistance of plastics to sliding wear using block-on-ring wear test—cumulative wear method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This test method covers laboratory procedures for determining the resistance of plastics to sliding wear. The test utilizes a block-on-ring friction and wear testing machine to rank plastics according to their sliding wear characteristics against metals or other solids. 1.2 An important attribute of this test is that it is very flexible. Any material that can be fabricated into, or applied to, blocks and rings can be tested. Thus, the potential materials combinations are endless. In addition, the test can be run with different gaseous atmospheres and elevated temperatures, as desired, to simulate service conditions. 1.3 Wear test results are reported as the volume loss in cubic millimetres for the block and ring. Materials of higher wear resistance will have lower volume loss. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with it...

  7. The effect of graphene content and sliding speed on the wear mechanism of nickel–graphene nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Algul, H., E-mail: halgul@sakarya.edu.tr; Tokur, M.; Ozcan, S.; Uysal, M.; Cetinkaya, T.; Akbulut, H.; Alp, A.

    2015-12-30

    Graphical abstract: - Highlights: • Graphene reinforced nickel matrix composites were produced by pulse electroplating method at a constant current density of 5 A/dm{sup 2}. • Incorporating graphene refines the grain size and changes the microstructure of the coating. • Incorporating graphene greatly improves the friction reduction and wear resistance of the coating. • The nickel/graphene composite coating containing 500 mg/L graphene in the electrolyte showed the best results. - Abstract: Nickel–graphene metal matrix composite coatings were fabricated by pulse electrodeposition technique from a Watt's type electrolyte. Effect of the graphene concentration in the electrolyte on the microstructure, microhardness, tribological features of nanocomposite coatings were evaluated in details. Microhardness of the composite coating was measured using a Vicker's microhardness indenter. The surfaces of the samples were characterized by scanning electron microscopy (SEM). Raman spectroscopy, EDS and XRD analysis were used to determine chemical composition and structure of composite coatings. The tribological behavior of the resultant composite coating was tested by a reciprocating ball-on disk method at constant load but varying sliding speeds for determination the wear loss and friction coefficient features against a counterface. The wear and friction variations of the electrodeposited nickel graphene nanocomposite coatings sliding against an M50 steel balls were carried out on a CSM Instrument. The friction and wear properties of the coatings were examined without any lubrication at room temperature in the ambient air. The change in wear mechanisms by changing graphene nanosheets content was also comprehensively studied.

  8. Research on Oxidation Wear Behavior of a New Hot Forging Die Steel

    Science.gov (United States)

    Shi, Yuanji; Wu, Xiaochun

    2018-01-01

    Dry sliding tests for the hot forging die steel DM were performed in air under the test temperature at 400-700 °C and the time of 0.5-4 h by a UMT-3 high-temperature wear tester. The wear behavior and characteristics were studied systematically to explore the general characters in severe oxidation conditions. The results showed that a mild-to-severe oxidation wear transition occurred with an increase in the test temperature and duration. The reason was clarified as the unstable M6C carbides coarsening should be responsible for the severe delamination of tribo-oxide layer. More importantly, an intense oxidation wear with lower wear rates was found when the experimental temperature reaches 700 °C or after 4 h of test time at 600 °C, which was closely related to the degradation behavior during wear test. Furthermore, a new schematic diagram of oxidation wear of DM steel was proposed.

  9. Development and Sliding Wear Response of Epoxy Composites Filled with Coal Mine Overburden Material

    Science.gov (United States)

    Das, Prithika; Satapathy, Alok; Mishra, M. K.

    2018-03-01

    The paper reports on development and characterization of epoxy based composites filled with micro-sized mine overburden material. Coal mine overburden material is typically highly heterogeneous and is considered as waste material. For excavating each ton of coal, roughly 5 tons of overburden materials are removed and is dumped nearby occupying large space. Gainful utilization of this waste is a major challenge. In the present work, this material is used as filler materials in making a new class of epoxy matrix composites. Composites with different weight proportions of fillers (0, 10, 20, 30 and 40) wt. % are prepared by hand layup technique. Compression tests are performed as per corresponding ASTM standards to assess the compressive strength of these composites. Further, dry sliding tests are performed following ASTM G99 standards using a pin on disk machine. A design of experiment approach based on Taguchi’s L16 orthogonal arrays is adopted. Tests are performed at different sliding velocities for multiple sliding distances under varying normal loads. Specific wear rates of the composites under different test conditions are obtained. The analysis of the test results revealed that the filler content and the sliding velocity are the most predominant control factors affecting the wear rate. This work thus, opens up a new avenue for the value added utilization of coal mine overburden material.

  10. Initial Sliding Wear Kinetics of Two Types of Glass Ionomer Cement: A Tribological Study

    Directory of Open Access Journals (Sweden)

    Cyril Villat

    2014-01-01

    Full Text Available The aim of this work was to characterize the initial wear kinetics of two different types of glass ionomer cement used in dentistry (the conventional glass ionomer cement and the resin-modified glass ionomer cement under sliding friction after 28-day storing in distilled water or Ringer’s solution. Sliding friction was applied through a pin-on-disk tribometer, in sphere-on-plane contact conditions, under 5 N normal load and 120 rotations per minute. The test lasted 7500 cycles and replicas were performed at 2500, 5000 and 7500 cycles. A profilometer was used to evaluate the wear volume. Data were analysed using Student’s t-test at a significant level of 5%. There is no statistical significant difference between the results obtained for a given material with the maturation media (P>0.05. However, for a given maturation medium, there are significant statistical differences between the data obtained for the two materials at each measurement (P<0.0001. The wear rates of both materials decrease continuously during the running-in period between 0 and 2500 cycles. After 2500 cycles, the wear rate becomes constant and equal for both materials. The resin matrix contained in the resin-modified glass ionomer cement weakens the tribological behaviour of this material.

  11. Sliding Wear Characteristics and Corrosion Behaviour of Selective Laser Melted 316L Stainless Steel

    Science.gov (United States)

    Sun, Y.; Moroz, A.; Alrbaey, K.

    2014-02-01

    Stainless steel is one of the most popular materials used for selective laser melting (SLM) processing to produce nearly fully dense components from 3D CAD models. The tribological and corrosion properties of stainless steel components are important in many engineering applications. In this work, the wear behaviour of SLM 316L stainless steel was investigated under dry sliding conditions, and the corrosion properties were measured electrochemically in a chloride containing solution. The results show that as compared to the standard bulk 316L steel, the SLM 316L steel exhibits deteriorated dry sliding wear resistance. The wear rate of SLM steel is dependent on the vol.% porosity in the steel and by obtaining full density it is possible achieve wear resistance similar to that of the standard bulk 316L steel. In the tested chloride containing solution, the general corrosion behaviour of the SLM steel is similar to that of the standard bulk 316L steel, but the SLM steel suffers from a reduced breakdown potential and is more susceptible to pitting corrosion. Efforts have been made to correlate the obtained results with porosity in the SLM steel.

  12. Application of x-ray diffraction techniques to the understanding of the dry sliding wear behaviour of aluminium and titanium

    International Nuclear Information System (INIS)

    Zoheir, N.; Ahmet, T.A.; Northwood, D.O.

    1996-01-01

    Dry sliding wear tests were performed on polycrystalline f.c.c. Al and h.c.p. Ti specimens using a block-on-ring type wear machine with a rotating ring made of 52100 bearing steel. The sliding speed was 0.13 m.s sup -l and the applied normal load was 10 N. The wear tests were performed on a single specimen in ambient conditions and the texture was evaluated during wear using an X-ray diffraction inverse pole figure technique at a range of sliding distances. Pole density distributions for the [0001] and [111) poles for of Ti and Al, respectively, were then determined from the inverse pole figures. The texture evolution during sliding wear was subsequently related to the friction and wear behaviour. For the aluminum sample, a (111) texture developed parallel to the worn surface with increasing sliding distance (a 6 fold increase in the (111) pole density as the sliding distance increases from 0 to 2714 m). The titanium sample (normal section) which had a preferred orientation with the basal poles, [0001), parallel to the contact surface prior to testing, an increase in wear, i.e. sliding distance, did not change the texture. However, for the transverse section of titanium, the basal pole, [0001), density parallel to the worn surface increased with increasing sliding distance. The shape of the coefficient of friction versus sliding distance curve is strongly influenced by crystallographic texturing. A drop in the coefficient of friction with the progressive development of the [111) and [0001) texture was observed for both Al and Ti (transverse section) specimens, respectively

  13. THE CORROSION BEHAVIOR AND WEAR RESISTANCE OF GRAY CAST IRON

    Directory of Open Access Journals (Sweden)

    Lina F. Kadhim

    2018-01-01

    Full Text Available Gray cast iron has many applications as pipes , pumps and valve bodies where it has influenced by heat and contact with other solutions . This research has studied the corrosion behavior and Vickers hardness of gray cast iron by immersion in four strong alkaline solutions (NaOH, KOH, Ca(OH2, LiOHwith three concentrations (1%,2%,3% of each solution. Dry sliding wear has carried out before and after the heat treatments (stress relief ,normalizing, hardening and tempering. In this work ,maximum wear strength has obtained at tempered gray cast iron and minimum corrosion rate has obtained in LiOH solution by forming protective white visible oxide layer.

  14. Microstructure and sliding wear characterization of Cu/TiB2 copper matrix composites fabricated via friction stir processing

    Directory of Open Access Journals (Sweden)

    I. Dinaharan

    2017-09-01

    Full Text Available The poor wear performance of copper is improved by reinforcing hard ceramic particles. The present work reports the fabrication of Cu/TiB2 (0, 6, 12, 18 vol.% copper matrix composites (CMCs using friction stir processing (FSP. TiB2 particles were initially packed together into a machined groove and were subjected to FSP under a constant set of process parameters. The microstructure was observed using optical, scanning and transmission electron microscopy. The wear behavior was examined using a pin-on-disc apparatus. The micrographs showed a homogeneous distribution of TiB2 particles without aggregation and segregation. The distribution of TiB2 particles was closely persistent across the stir zone. TiB2 particles were well bonded with the copper matrix without any interfacial reaction. Many TiB2 particles fractured during FSP. The grains in the composite were extensively refined because of dynamic recrystallization and pinning effect of TiB2 particles. The wear behavior under dry sliding condition was presented in detail.

  15. Erosion by sliding wear in granular flows: Experiments with realistic contact forces

    Science.gov (United States)

    Stark, C. P.; Hung, C. Y.; Smith, B.; Li, L.; Grinspun, E.; Capart, H.

    2015-12-01

    Debris flow erosion is a powerful and sometimes dominant process in steep channels. Despite its importance, this phenomenon is relatively little studied in the lab. The large drum experiments of Hsu are a notable exception, in which almost-field-scale impact forces were generated at the head of a synthetic debris flow whose properties (grain size, proportion of fines, etc) were varied widely.A key challenge in these and similar experiments is to explore how erosion rate varies as a function of the scale of the flow (thereby varying inertial stresses, impact forces, etc). The geometrical limitations of most lab experiments, and their short run time, severely limit the scope of such explorations.We achieve this scale exploration in a set of drum erosion experiments by varying effective gravity across several orders of magnitude (1g, 10g, 100g) in a geotechnical centrifuge. By half-filling our 40cm-diameter drum with dry 2.3mm grains, placing a synthetic rock plate at the back and a glass plate at the front 3cm apart, and rotating the drum at 1-50rpm, we simulate wear in a channelized dry granular flow. In contrast to Hsu's experiments, we focus on sliding wear erosion at the flow boundary rather than impact/frictional wear at the flow head. By varying effective gravity from 1g-100g we can tune the pressure exerted by the grains at the boundary without having to change the scale of our apparatus. Using a recently developed depth-averaged, kinetic-energy closure theory for granular flow, we can simultaneously tune the drum rotation rate such that the flow dynamics remain invariant. We can thereby explore how changing the scale of a granular flow, and thus the contact forces of grains on the boundary, controls the rate of rock erosion. Using a small apparatus we can simulate the erosion generated by debris flows several meters deep involving grains up to 10cm in diameter.Our results suggest that sliding wear is the main erosion process, and are consistent with Archard

  16. Sliding wear characteristics of carburized steels and thermally refined steels implanted with nitrogen ions

    International Nuclear Information System (INIS)

    Terashima, Keiichi; Koda, Hiroyuki; Takeuchi, Eiichi.

    1995-01-01

    In order to concretely examine the application of surface reforming by ion implantation, nitrogen ion implantation was applied to the thermally refined steels S45C and SCM440 and the carburized steel SCM415, which are high versatile steels for mechanical structures, and their friction and wear characteristics were examined. The results are summarized as follows. In the surface-reformed material, in which nitrogen was implanted for the purpose of improving the seizure durability of the carburized steel, the load-frictional coefficient curve in lubricated sliding friction was similar to that of the material without implantation, but it was recognized that the load at which seizure occurred reached 2000 kgf or more, and as the amount of implantation was more, the material withstood higher load. In the lubricated sliding friction using a pin-ring type wear testing machine of the thermally refined steels and those to which implantation was applied, it was recognized that the specific wear amount was less in the implanted steels than in those without implantation. The results of the analysis of the implanted surface layers and the friction surfaces are reported. (K.I.)

  17. Wear Behavior of Woven Roving Aramid / Epoxy Composite under Different Conditions

    Directory of Open Access Journals (Sweden)

    Asad A. Khalid

    2012-09-01

    Full Text Available Wear behavior studies of aramid woven roving /epoxy composite has been conducted. Sliding the material against smooth steel counter face under dry and  lubricated with oil conditions has been investigated. Powder of Silicon carbide has been mixed with the epoxy resin and tested also. The powder was mixed in a volumetric fraction of 10% with the epoxy resin. Four Laminates of six layers were fabricated by hand lay up  method. A pin on disc apparatus has been fabricated to conduct the sliding wear tests on specimens of (4 mm   4 mm   12 mm in size have been cut from the four laminates. The effect of sliding condition including dry, lubricated, dry with additives and lubricated with additives have been studied. Wear rate tests have been conducted at different sliding speeds and loads. Results show that the wear characteristics are influenced by the operating conditions and the construction of the composite material used. It was also found that the wear of aramid /epoxy composite onto the steel counter face were significantly reduced by using lubricant and additives but still took place.Keywords: Wear, Composite materials, Woven roving aramid, Epoxy, Additives, Lubricant.

  18. The influence of reciprocating sliding wear on the oxidation behaviour of Fe-12Cr steel

    International Nuclear Information System (INIS)

    Smith, A.F.

    1988-04-01

    Medium-chromium ferritic alloys are used extensively in the boiler and core sections of advanced gas cooled reactors. It was discovered in the early 1970s, that under certain conditions these alloys could undergo the phenomenon known as breakaway oxidation. In this type of oxidation the rate limiting step is located at the oxide/metal interface rather than the more usual gas/oxide interface and results in linear oxidation kinetics. It has been shown that repeated removal of oxide layers can expose chromium depleted metal to the oxidising gas and promote nucleation of breakaway oxidation. The question has been addressed as to whether high temperature sliding wear processes can also disrupt the surface so as to make the material potentially susceptible to breakaway oxidation. To this end high temperature reciprocating wear of Fe-12Cr material in both low and high pressure reactor gas has been investigated. (author)

  19. Experimental Investigation of Friction Coefficient and Wear Rate of Composite Materials Sliding Against Smooth and Rough Mild Steel Counterfaces

    Directory of Open Access Journals (Sweden)

    M.A. Chowdhury

    2013-12-01

    Full Text Available In the present study, friction coefficient and wear rate of gear fiber reinforced plastic (gear fiber and glass fiber reinforced plastic (glass fiber sliding against mild steel are investigated experimentally. In order to do so, a pin on disc apparatus is designed and fabricated. Experiments are carried out when smooth or rough mild steel pin slides on gear fiber and glass fiber disc. Experiments are conducted at normal load 10, 15 and 20 N, sliding velocity 1, 1.5 and 2 m/s and relative humidity 70%. Variations of friction coefficient with the duration of rubbing at different normal loads and sliding velocities are investigated. Results show that friction coefficient is influenced by duration of rubbing, normal load and sliding velocity. In general, friction coefficient increases for a certain duration of rubbing and after that it remains constant for the rest of the experimental time. The obtained results reveal that friction coefficient decreases with the increase in normal load for gear fiber and glass fiber mating with smooth or rough mild steel counterface. On the other hand, it is also found that friction coefficient increases with the increase in sliding velocity for both of the tested materials. Moreover, wear rate increases with the increase in normal load and sliding velocity. The magnitudes of friction coefficient and wear rate are different depending on sliding velocity and normal load for both smooth and rough counterface pin materials.

  20. Seismic behavior with sliding of overhead travelling crane

    International Nuclear Information System (INIS)

    Komori, Akio; Ueki, Takashi; Hirata, Masami; Hoshii, Tsutomu; Kashiwazaki, Akihiro.

    1989-01-01

    In this study, the seismic behavior of an overhead travelling crane with the sliding between travelling wheels and rails is examined. First, the dynamic characteristic test of the actual crane installed in a reactor building and the sliding test of the rigid-element model to observe the basic sliding characteristic were performed. Next, to examine the dynamic response with sliding, shaking tests using the scaled model of an actual crane were conducted. From these results, useful design information about seismic behavior of an overhead travelling crane was obtained. It was also observed that numerical predictions considering sliding behavior have good agreement with the experimental results and are applicable to seismic design. (author)

  1. Comparison of sliding friction and wear behaviour of overhead conveyor steels tested under dry and lubrication conditions

    International Nuclear Information System (INIS)

    Castro-Regal, G.; Fernandez-Vicente, A.; Martinez, M. A.

    2005-01-01

    The sliding friction and wear behaviour of different steel qualities were investigated with and without lubrication conditions. Steel qualities tested are normally used in the overhead conveyor system of many industrial fields, like the automotive sector. Sliding wear tests have been conducted by means of a pin-on-disk machine. A 100Cr6 steel similar to that used within the overhead conveyor trolleys has been employed as a pin. Friction coefficient values obtained under lubrication conditions were three times smaller than those obtained without lubrication. The mechanism that controls wear behaviour under lubrication conditions is an abrasive one and the wear values obtained are almost worthless. On the other hand, mechanism controlling wear during non lubrication tests, was a combination of abrasion and adhesion. (Author) 20 refs

  2. Initial sliding wear kinetics of two types of glass ionomer cement: a tribological study.

    Science.gov (United States)

    Villat, Cyril; Ponthiaux, Pierre; Pradelle-Plasse, Nelly; Grosgogeat, Brigitte; Colon, Pierre

    2014-01-01

    The aim of this work was to characterize the initial wear kinetics of two different types of glass ionomer cement used in dentistry (the conventional glass ionomer cement and the resin-modified glass ionomer cement) under sliding friction after 28-day storing in distilled water or Ringer's solution. Sliding friction was applied through a pin-on-disk tribometer, in sphere-on-plane contact conditions, under 5 N normal load and 120 rotations per minute. The test lasted 7500 cycles and replicas were performed at 2500, 5000 and 7500 cycles. A profilometer was used to evaluate the wear volume. Data were analysed using Student's t-test at a significant level of 5%. There is no statistical significant difference between the results obtained for a given material with the maturation media (P > 0.05). However, for a given maturation medium, there are significant statistical differences between the data obtained for the two materials at each measurement (P glass ionomer cement weakens the tribological behaviour of this material.

  3. Wear Behavior of Medium Carbon Steel with Biomimetic Surface Under Starved Lubricated Conditions

    Science.gov (United States)

    Zhang, Zhihui; Shao, Feixian; Liang, Yunhong; Lin, Pengyu; Tong, Xin; Ren, Luquan

    2017-07-01

    Friction and wear under starved lubrication condition are both key life-related factors for mechanical performance of many structural parts. In this paper, different surface morphologies on medium carbon steel were fabricated using laser, inspired by the surface coupling effect of biological system. The friction and sliding wear behaviors of biomimetic specimens (characterized by convex and concave units on the specimen surface) were studied under starved lubrication condition. The stress distribution on different sliding surfaces under sliding friction was studied using finite element method. The results showed that the tribological performance of studied surfaces under starved lubrication condition depended not only on the surface morphology but also on the structure of biomimetic units below surface (subsurface structure). The friction coefficient of biomimetic surface was effectively reduced by the concave unit depth, while the refined microstructure with higher hardness led to the much better wear resistance. In addition to lubricant reserving and wear debris trapping effect derived from the surface concave morphology, it was believed that the well-formed subsurface structure of biomimetic units could carry much heavy loads against tribopair, which enhanced the function of surface topography and resulted in complementary lubrication in the wear contact area. The uniform stress distribution on the entire biomimetic surface also played an important role in stabilizing the friction coefficient and reducing the wear cracks.

  4. Tribological behaviors of graphite sliding against cemented carbide in CaCl2 solution

    International Nuclear Information System (INIS)

    Guo, Fei; Tian, Yu; Liu, Ying; Wang, Yuming

    2015-01-01

    The tribological behaviors of graphite sliding against cemented carbide were investigated using a standard tribological tester Plint TE92 in a ring-on-ring contact configuration in both CaCl 2 solution and deionized water. An interesting phenomenon occurred: as the CaCl 2 solution concentration increased, the friction coefficient firstly decreased and was lower than that in the deionized water, and then gradually increased, exceeding the friction coefficient in the deionized water. The wear rate of the ,graphite also presented the same variation trend. According to the polarization curves of cemented carbide, contact angle measurements, Raman spectrum analysis and scanning electron microscope (SEM) images analysis, the above friction and wear behaviors of graphite sliding against cemented carbide were attributed to the graphite surface wettability and the cemented carbide surface corrosion property. (paper)

  5. Sliding behavior of boron ion-implanted 304 stainless steel

    International Nuclear Information System (INIS)

    Shrivastava, S.; Jain, A.; Singh, C.

    1995-01-01

    The authors have studied the influence of boron ion implantation on the friction and wear behavior of 304 stainless steel. The authors find an increase in microhardness following implantation. The authors also observed a reduction in wear and coefficient of friction. They have measured the microhardness, inside the wear tracks and have found a large increase in the values in the unimplanted specimens and only a small increase in the implanted specimens. These observations have thrown light on the change in the wear mechanism between the two cases. The authors have also used Scanning Electron Microscopy and Energy Dispersive Analysis of X-rays, to characterize the differences in the mode of wear. The change in wear behavior is brought about by the ability of boron to prevent the surface from transforming into a hard brittle layer during wear

  6. Wear behavior of Al-7%Si-0.3%Mg/melon shell ash particulate composites.

    Science.gov (United States)

    Abdulwahab, M; Dodo, R M; Suleiman, I Y; Gebi, A I; Umar, I

    2017-08-01

    The present study examined wear characteristics of A356/melon shell ash particulate composites. Dry-sliding the stainless steel ball against specimen disc revealed the abrasive wear behavior of the composites under loads of 2 and 5N. The composite showed lower wear rate of 2.182 × 10 -4 mm 3 /Nm at 20 wt% reinforced material under load of 5N. Results showed that wear rate decreased significantly with increasing weight percentage of melon shell ash particles. Microstructural analyses of worn surfaces of the composites reveal evidence of plastic deformation of matrix phase. The wear resistance of A356 increased considerably with percentage reinforcement. In other words, the abrasive mass loss decreased with increasing percentage of reinforcement addition at the both applied loads. The control sample suffered a highest mass loss at 5 N applied load.

  7. Microstructure and wear behavior of friction stir processed cast hypereutectic aluminum silicon

    Directory of Open Access Journals (Sweden)

    Ahmad Rosli

    2017-01-01

    Full Text Available Hypereutectic as-cast Al-18Si-Cu-Ni alloy was subjected to friction stir processing (FSP. The resultant effect of FSP on the alloy was evaluated by microstructure analysis and wear tests (dry sliding. A significant microstructural modification and enhancement in wear behavior of Al-18Si-Cu-Ni alloy was recorded after friction stir processing. Wear resistance improvement was related to considerable modification in size, morphology and distribution of silicon particles, and hardness improvement. It was found that lower tool rotation speed was more effective to refine silicon particles and in turn increase wear resistance. Minimum Si particle mean area of about 47.8 µm2, and wear rate of 0.0155 mg/m was achieved.

  8. The Effect of Counterpart Material on the Sliding Wear of TiAlN Coatings Deposited by Reactive Cathodic Pulverization

    Directory of Open Access Journals (Sweden)

    Michell Felipe Cano Ordoñez

    2015-11-01

    Full Text Available This work aims to study the effect of the counterpart materials (100Cr6, Al2O3 and WC-Co on the tribological properties of TiAlN thin films deposited on AISI H13 steel substrate by reactive magnetron co-sputtering. The structural characterization of the TiAlN films, performed by X-ray diffraction, showed (220 textured fcc crystalline structure. The values of hardness and elastic modulus obtained by nanoindentation were 27 GPa and 420 GPa, respectively, which resulted in films with a relatively high resistance to plastic deformation. Ball-on-disk sliding tests were performed using normal loads of 1 N and 3 N, and 0.10 m/s of tangential velocity. The wear coefficient of the films was determined by measuring the worn area using profilometry every 1000 cycles. The mechanical properties and the chemical stability of the counterpart material, debris formation and the contact stress influences the friction and the wear behavior of the studied tribosystems. Increasing the hardness of the counterpart decreases the coefficient of friction (COF due to lower counterpart material transference and tribofilm formation, which is able to support the contact pressure. High shear stress concentration at the coating/substrate interface was reported for higher load promoting failure of the film-substrate system for all tribopairs

  9. Experimental Investigation of Friction Coefficient and Wear Rate of Composite Materials Sliding Against Smooth and Rough Mild Steel Counterfaces

    OpenAIRE

    M.A. Chowdhury; D.M. Nuruzzaman; B.K. Roy; S. Samad; R. Sarker; A.H.M. Rezwan

    2013-01-01

    In the present study, friction coefficient and wear rate of gear fiber reinforced plastic (gear fiber) and glass fiber reinforced plastic (glass fiber) sliding against mild steel are investigated experimentally. In order to do so, a pin on disc apparatus is designed and fabricated. Experiments are carried out when smooth or rough mild steel pin slides on gear fiber and glass fiber disc. Experiments are conducted at normal load 10, 15 and 20 N, sliding velocity 1, 1.5 and 2 m/s and relative h...

  10. Wear Resistance Properties Reinforcement Using Nano-Al/Cu Composite Coating in Sliding Bearing Maintenance.

    Science.gov (United States)

    Liu, Hongtao; Li, Zhixiong; Wang, Jianmei; Sheng, Chenxing; Liu, Wanli

    2018-03-01

    Sliding bearing maintenance is crucial for reducing the cost and extending the service life. An efficient and practical solution is to coat a restorative agent onto the worn/damaged bearings. Traditional pure-copper (Cu) coating results in a soft surface and poor abrasion resistance. To address this issue, this paper presents a nano-composite repairing coating method. A series of nano-Al/Cu coatings were prepared on the surface of 45 steel by composite electro-brush plating (EBP). Their micro-hardness was examined by a MHV-2000 Vickers hardness tester, and tribological properties by a UMT-2M Micro-friction tester, 3D profiler and SEM. Then, the influence of processing parameters such as nano-particle concentration and coating thickness on the micro-hardness of nano-Al/Cu coating was analyzed. The experimental analysis results demonstrate that, when the nano-Al particle concentration in electrolyte was 10 g/L, the micro-hardness of the composite coating was 1.1 times as much as that of pure-Cu coating. When the Al nano-particle concentration in electrolyte was 20 g/L, the micro-hardness of the composite coating reached its maximum value (i.e., 231.6 HV). Compared with the pure-Cu coating, the hardness and wear resistance of the nano-composite coating were increased, and the friction coefficient and wear volume were decreased, because of the grain strengthening and dispersion strengthening. The development in this work may provide a feasible and effective nano-composite EBP method for sliding bearing repair.

  11. Wear calculation possibility of slide-friction pair "shaft-plain bearing" for four-stroke engines

    Science.gov (United States)

    Springis, Guntis; Rudzitis, Janis; Avisane, Anita; Kumermanis, Maris

    2013-12-01

    The issues of the service life and its prediction for main four stroke engine parts such as shaft-plain bearing have always been of particular importance. The article determines the most suitable mathematical calculation model allowing considering the set of parameters needed for the slide-friction pair's calculation, thus achieving a result as precise as possible. Since the wear process is variable and many-sided it is influenced by very many different parameters, for example, the surface geometry (roughness, waviness, form deviation, etc.), the physical and mechanical conditions of the upper layer, component material, wear regime, wear temperature, etc. The offered wear calculation model taking into consideration as much as possible wear affecting parameters is based on the fatigue theory regularities of the friction surface's destroying, using the approach of probability theory.

  12. Influence of Rock Properties on Wear of M and SR Grade Rubber with Varying Normal Load and Sliding Speed

    Directory of Open Access Journals (Sweden)

    Pal Samir Kumar

    2017-09-01

    Full Text Available Rubbers are interesting materials and are extensively used in many mining industries for material transportation. Wear of rubber is a very complex phenomenon to understand. The present study aims to explain the influence of rock properties on wear of M and SR grade rubber used in top cover of conveyor belts. Extensive laboratory experiments were conducted under four combinations of normal load and sliding speed. The wear of both the rubber types were analyzed based on the rock properties like shear strength, abrasivity index and fractal dimension. A fully instrumented testing set up was used to study the wear of rubber samples under different operating conditions. In general, wear was higher for M grade rubber compared to SR grade rubber. Increase in shear strength of rocks depicts decreasing trend for the wear of M and SR grade rubber at lower load conditions. Moreover, a higher load combination displays no definite trend in both the rubbers. The strong correlation between the wear of rubber and frictional power for all rubber-rock combinations has given rise to the parameter A, which reflects the relative compatibility between the rubber and rock. Increase of Cerchar’s Abrasivity Index of rocks shows gradual enhancement in wear for M grade rubber in all the load and speed combinations whereas, it fails in SR grade rubber due to its higher strength. The wear of rubber tends to decrease marginally with the surface roughness of rocks at highest normal load and sliding speed in M grade rubber. However, the wear of M and SR grade rubber is influenced by the surface roughness of rocks.

  13. Study of Surface Wear and Damage Induced by Dry Sliding of Tempered AISI 4140 Steel against Hardened AISI 1055 Steel

    Directory of Open Access Journals (Sweden)

    A. Elhadi

    2016-12-01

    Full Text Available In industry, the sliding mechanical systems are subject to friction and wear phenomena. These phenomena can be the origin of a reduction of the efficiency of the mechanical system even to be responsible for its incapacity. Generally, the materials of the parts which are moving relative (tribological couple of these systems are low alloy steels and carbon steels, thanks to their good mechanical and tribological properties. The present work aimed to study, the surface wear and damage induced by dry sliding of hard carbon steel AISI 1055 (disc against tempered low alloy steel AISI 4140 (pin with different hardness and applied loads was investigated. The results revealed that the interaction between the applied load and pin hardness result in complex thermo-mechanical behaviour of the worn surfaces. When a lower hardness pin is used, the main wear mechanisms observed on the discs were abrasion, adhesion, and oxidation. When a higher hardness pin is used, the wear of the discs is governed by delamination, oxidation, and plastic deformation. In particular, third-body wear occurs at high applied load resulting in higher wear rate of high hardness pins compared to low hardness pins.

  14. The unlubricated reciprocating sliding wear of 316 stainless steel in C02 in the temperature range 20 to 6000C

    International Nuclear Information System (INIS)

    Smith, A.F.

    1985-11-01

    The friction and wear behaviour of 316 stainless steel in C0 2 has been investigated in the load range 8 - 5ON from 20 to 600 0 C. Wear transitions occurred at all temperatures but were load dependent. At and below 300 0 C wear transitions only took place at low leads whereas above 300 0 C transitions were seen al all loads. The low temperature wear transition, giving an order of magnitude decrease in wear rate was associated with a change in friction behaviour. The friction force across the specimen was initially widely fluctuating and varied from cycle to cycle. After a time, which did not necessarily coincide with the wear transition the cyclic variation in the friction force become much less. This smoother sliding is thought to indicate a trend to oxide -oxide contacts. At higher temperatures wear transitions result in a two orders of magnitude reduction in wear. The corresponding friction transition was similar to the low temperature friction change but also included a marked temporary drop in the coefficient of friction. (author)

  15. Wear Behavior and Microstructure of Mg-Sn Alloy Processed by Equal Channel Angular Extrusion.

    Science.gov (United States)

    Chen, Jung-Hsuan; Shen, Yen-Chen; Chao, Chuen-Guang; Liu, Tzeng-Feng

    2017-11-16

    Mg-5wt.% Sn alloy is often used in portable electronic devices and automobiles. In this study, mechanical properties of Mg-5wt.% Sn alloy processed by Equal Channel Angular Extrusion (ECAE) were characterized. More precisely, its hardness and wear behavior were measured using Vickers hardness test and a pin-on-disc wear test. The microstructures of ECAE-processed Mg-Sn alloys were investigated by scanning electron microscope and X-ray diffraction. ECAE process refined the grain sizes of the Mg-Sn alloy from 117.6 μm (as-cast) to 88.0 μm (one pass), 49.5 μm (two passes) and 24.4 μm (four passes), respectively. Meanwhile, the hardness of the alloy improved significantly. The maximum wear resistance achieved in the present work was around 73.77 m/mm³, which was obtained from the Mg-Sn alloy treated with a one-pass ECAE process with a grain size of 88.0 μm. The wear resistance improvement was caused by the grain size refinement and the precipitate of the second phase, Mg₂Sn against the oxidation of the processed alloy. The as-cast Mg-Sn alloy with the larger grain size, i.e., 117.6 μm, underwent wear mechanisms, mainly adhesive wear and abrasive wear. In ECAE-processed Mg-Sn alloy, high internal energy occurred due to the high dislocation density and the stress field produced by the plastic deformation, which led to an increased oxidation rate of the processed alloy during sliding. Therefore, the oxidative wear and a three-body abrasive wear in which the oxide debris acted as the three-body abrasive components became the dominant factors in the wear behavior, and as a result, reduced the wear resistance in the multi-pass ECAE-processed alloy.

  16. Wear Evaluation of AISI 4140 Alloy Steel with WC/C Lamellar Coatings Sliding Against EN 8 Using Taguchi Method

    Science.gov (United States)

    Kadam, Nikhil Rajendra; Karthikeyan, Ganesarethinam

    2016-10-01

    The purpose of the experiments in this paper is to use the Taguchi methods to investigate the wear of WC/C coated nitrided AISI 4140 alloy steel. A study of lamellar WC/C coating which were deposited by a physical vapor deposition on nitrided AISI 4140 alloy steel. The investigation includes wear evaluation using Pin-on-disk configuration. When WC/C coated AISI 4140 alloy steel slides against EN 8 steel, it was found that carbon-rich coatings show much lower wear of the countersurface than nitrogen-rich coatings. The results were correlated with the properties determined from tribological and mechanical characterization, therefore by probably selecting the proper processing parameters the deposition of WC/C coating results in decreasing the wear rate of the substrate which shows a potential for tribological application.

  17. Friction and Wear of Nanoadditive-Based Biolubricants in Steel-Steel Sliding Contacts: A Comparative Study

    Science.gov (United States)

    Gupta, Rajeev Nayan; Harsha, A. P.

    2018-02-01

    The present work deals with the study of tribo-pair interaction in lubricated sliding contacts. By considering the environmental issues, the sunflower oil was extracted from the sunflower seeds and used as a base lubricant. The two types of the nanoadditives, i.e., CuO and CeO2, varying concentrations from 0.10 to 0.50% w/v were used to formulate the nanolubricants. The compatibility/synergism of the nanoadditives was examined from antifriction and antiwear behavior study with four-ball tester. Also, sunflower oil was modified by the chemical method to improve its fatty acid structure. A comparative tribological and compatibility study was also done in modified oil at similar concentration levels with both types of nanoparticles. The tribological test result exhibits 0.10% w/v concentration of the nanoadditive as optimum due to lowest wear scar and coefficient of friction. Higher concentration of the nanoparticles impaired the base oil performance. Different analytical tools were used to characterize the oil modification and worn surfaces. Moreover, the role of subsurface of the contacting material with the tribological performance has been reported.

  18. Early stages of sliding wear behaviour of Al2O3 and SiC reinforced aluminium

    International Nuclear Information System (INIS)

    Bonollo, F.; Ceschini, L.; Garagnani, G.L.; Palombarini, G.; Tangerini, I.; Zambon, A.

    1993-01-01

    Al matrix composites reinforced by 10 vol.% Al 2 O 3 and SiC particles were subjected to dry sliding tests against steel using a slider-on-cylinder tribometer. Damage mechanisms were 'micro-machining' of the steel carried out by ceramic particles, plastic deformation and oxidation of the metal matrix, as well as abrasion. The results were discussed on the basis of the third-body wear model. (orig.)

  19. Effect of Microstructure on the Wear Behavior of Heat Treated SS-304 Stainless Steel

    Directory of Open Access Journals (Sweden)

    S. Kumar

    2016-12-01

    Full Text Available Sliding wear characteristics of some heat treated SS-304 stainless steel against EN-8 steel in dry condition have been studied in the present experimental work. Samples of SS-304 stainless steel have been heated in a muffle furnace in desired temperature and allowed to dwell for two hours. The heated specimen are then cooled in different media namely inside the furnace, open air, cutting grade oil (grade 44 and water at room temperature to obtain different grades of heat treatment. Microstructures and corresponding micro hardness of the samples have been measured along with Feritscopic studies. Wear characteristics have been studied in a multi tribo-tester (Ducom in dry sliding condition against EN-8 steel roller. Speed, load on job and duration of test run have been considered as the experimental parameters. The wear of the samples have been obtained directly from ‘Winducom 2006’ software. Mass loss of the samples before and after operation has also been considered as the measure of wear in the present study. All the samples have been slid against EN-8 steel roller with fixed experimental parameters. The data have been plotted, compared and analyzed. Effect of microstructures as well as micro hardness on the wear behavior has been studied and concluded accordingly.

  20. Dry sliding wear behaviour of heat treated iron based powder metallurgy steels with 0.3% Graphite + 2% Ni additions

    International Nuclear Information System (INIS)

    Tekeli, S.; Gueral, A.

    2007-01-01

    To determine the effect of various heat treatments on the microstructure and dry sliding wear behaviour of iron based powder metallurgy (PM) steels, atomized iron powder was mixed with 0.3% graphite + 2% Ni. The mixed powders were cold pressed at 700 MPa and sintered at 1200 deg. C for 30 min under pure Ar gas atmosphere. One of the sintered specimens was quenched from 890 deg. C and then tempered at 200 deg. C for 1 h. The other sintered specimens were annealed at different intercritical heat treatment temperatures of 728 and 790 deg. C and water quenched. Through this intercritical annealing heat treatment, the specimens with various ferrite + martensite volume fractions were produced. Wear tests were carried out on the quenched + tempered and intercritically annealed specimens under dry sliding conditions using a pin-on-disk type machine at constant load and speed and the results were compared in terms of microstructure, hardness and wear strength. It was seen that hardness and wear strength in intercritically annealed specimens were higher than that of quenched + tempered specimen

  1. Tribological wear behavior of diamond reinforced composite coating

    International Nuclear Information System (INIS)

    Venkateswarlu, K.; Ray, Ajoy Kumar; Gunjan, Manoj Kumar; Mondal, D.P.; Pathak, L.C.

    2006-01-01

    In the present study, diamond reinforced composite (DRC) coating has been applied on mild steel substrate using thermal spray coating technique. The composite powder consists of diamond, tungsten carbide, and bronze, which was mixed in a ball mill prior deposition by thermal spray. The microstructure and the distribution of diamond and tungsten carbide particle in the bronze matrix were studied. The DRC-coated mild steel substrates were assessed in terms of their high stress abrasive wear and compared with that of uncoated mild steel substrates. It was observed that when sliding against steel, the DRC-coated sample initially gains weight, but then loses the transferred counter surface material. In case of abrasive wear, the wear rate was greatly reduced due to the coating; wherein the wear rate decreased with increase in diamond content

  2. Wear Micro-Mechanisms of Composite WC-Co/Cr - NiCrFeBSiC Coatings. Part I: Dry Sliding

    Directory of Open Access Journals (Sweden)

    D. Kekes

    2014-12-01

    Full Text Available The influence of the cermet fraction in cermet/ metal composite coatings developed by High-Velocity Oxyfuel Flame (HVOF spraying on their tribological behaviour was studied. Five series of coatings, each one containing different proportion of cermet-metal components, prepared by premixing commercially available feedstocks of NiCrFeBSiC metallic and WC-Co/Cr cermet powders were deposited on AISI 304 stainless steel substrate. The microstructure of as-sprayed coatings was characterized by partial decomposition of the WC particles, lamellar morphology and micro-porosity among the solidified splats. Tribological behavior was studied under sliding friction conditions using a Si3N4 ball as counterbody and the friction coefficient and volume loss were determined as a function of the cermet fraction. Microscopic examinations of the wear tracks and relevant cross sections identified the wear mechanisms involved. Coatings containing only the metallic phase were worn out through a combination of ploughing, micro-cracking and splat exfoliation, whilst those containing only the cermet phase primarily by micro-cracking at the individual splat scale. The wear mechanisms of the composite coatings were strongly affected by their randomly stratified structure. In-depth cracks almost perpendicular to the coating/ substrate interface occurring at the wear track boundaries resulted in cermet trans-splat fracture.

  3. High Temperature Sliding Wear of NiAl-based Coatings Reinforced by Borides

    Directory of Open Access Journals (Sweden)

    Oleksandr UMANSKYI

    2016-05-01

    Full Text Available The development of composite materials (CM in the systems “metal-refractory compound” is one of the up-to-date trends in design of novel materials aimed at operating under the conditions of significant loads at high temperature. To design such material, NiAl, which is widely used for deposition of protective coatings on parts of gas-turbine engines, was selected for a matrix. To strengthen a NiAl under the conditions of intense wear and a broad temperature range (up to 1000 °C, it is reasonable to add refractory inclusions. Introduction of refractory borides into matrix leads to a marked increase in metal wear resistance. In order to research the behavior of the designed composites at high temperatures and to study the influence of oxides on the friction processes, the authors carried out high temperature oxidation of CM of the above systems at 1000 °С for 90 min. It was determined that all of the composites were oxidized selectively and that the thickness of oxide layers formed on the boride inclusions is 3 – 7 times that on the oxides formed on the NiAl matrix. The mechanism of wear of gas-thermal coatings of the NiAl – МеB2 systems was studied for conditions of high temperature tribotests using the «pin-on-disc» technique. The obtained results indicate that introduction of TiB2, CrB2 and ZrB2 leads to their more intense oxidation during high temperature tribotests as compared to the matrix. The oxides formed on refractory borides act as solid lubricants, which promote a decrease in wear of the contact friction pairs. For more detailed investigation of the effect of tribo-oxidation products on the friction processes, tribotests were conducted for prior oxidized (at 900 °С coatings NiAl – 15 wt.% CrB2 (TiB2, ZrB2.DOI: http://dx.doi.org/10.5755/j01.ms.22.1.8093

  4. Wear Behavior of an Unstable Knee: Stabilization via Implant Design?

    OpenAIRE

    Reinders, Jörn; Sonntag, Robert; Kretzer, Jan Philippe

    2014-01-01

    Background. Wear-related failures and instabilities are frequent failure mechanisms of total knee replacements. High-conforming designs may provide additional stability for the joint. This study analyzes the effects of a ligamentous insufficiency on the stability and the wear behavior of a high-conforming knee design. Methods. Two simulator wear tests were performed on a high-conforming total knee replacement design. In the first, a ligamentous-stable knee replacement with a sacrificed anteri...

  5. High Temperature Dry Sliding Friction and Wear Performance of Laser Cladding WC/Ni Composite Coating

    Directory of Open Access Journals (Sweden)

    YANG Jiao-xi

    2016-06-01

    Full Text Available Two different types of agglomerate and angular WC/Ni matrix composite coatings were deposited by laser cladding. The high temperature wear resistance of these composite coatings was tested with a ring-on-disc MMG-10 apparatus. The morphologies of the worn surfaces were observed using a scanning electron microscopy (SEM equipped with an energy dispersive spectroscopy (EDS for elemental composition. The results show that the high temperature wear resistance of the laser clad WC/Ni-based composite coatings is improved significantly with WC mass fraction increasing. The 60% agglomerate WC/Ni composite coating has optimal high temperature wear resistance. High temperature wear mechanism of 60% WC/Ni composite coating is from abrasive wear of low temperature into composite function of the oxidation wear and abrasive wear.

  6. An Investigation of the Influence of Initial Roughness on the Friction and Wear Behavior of Ground Surfaces

    Science.gov (United States)

    Liang, Guoxing; Schmauder, Siegfried; Lyu, Ming; Schneider, Yanling; Zhang, Cheng; Han, Yang

    2018-01-01

    Friction and wear tests were performed on AISI 1045 steel specimens with different initial roughness parameters, machined by a creep-feed dry grinding process, to study the friction and wear behavior on a pin-on-disc tester in dry sliding conditions. Average surface roughness (Ra), root mean square (Rq), skewness (Rsk) and kurtosis (Rku) were involved in order to analyse the influence of the friction and wear behavior. The observations reveal that a surface with initial roughness parameters of higher Ra, Rq and Rku will lead to a longer initial-steady transition period in the sliding tests. The plastic deformation mainly concentrates in the depth of 20–50 μm under the worn surface and the critical plastic deformation is generated on the rough surface. For surfaces with large Ra, Rq, low Rsk and high Rku values, it is easy to lose the C element in, the reciprocating extrusion. PMID:29401703

  7. Friction and wear behavior of laser cladding Ni/hBN self-lubricating composite coating

    International Nuclear Information System (INIS)

    Zhang Shitang; Zhou Jiansong; Guo Baogang; Zhou Huidi; Pu Yuping; Chen Jianmin

    2008-01-01

    Ni/hBN coating was successfully prepared on 1Cr18Ni9Ti stainless steel substrate by means of laser cladding. The microhardness profile of the composite coating along the depth direction was measured, while its cross-sectional microstructures and phase compositions were analyzed by means of scanning electron microscopy and X-ray diffraction. Moreover, the friction and wear behavior of the composite coatings sliding against Si 3 N 4 from ambient to 800 deg. C was evaluated using a ball-on-disc friction and wear tester, and the worn surface morphologies of the composite coatings and counterpart ceramic balls were observed using a scanning electron microscope. At the same time, the worn surfaces of the ceramic balls were also analyzed using a 3D non-contact surface mapping profiler as well. It was found that the laser cladding Ni/hBN coating on the stainless steel substrate had high microhardness and good friction-reducing and antiwear abilities at elevated temperatures up to 800 deg. C. The composite coating registered slightly increased friction coefficient and wear rate as the temperature rose from ambient to 100 deg. C; then the friction coefficient and wear rate decreased with increasing temperature up to 800 deg. C (with the slight increase in the wear rate at 700 deg. C and 800 deg. C to be an exception). The laser cladding Ni/hBN coating was dominated by mixed adhesion and abrasive wear as it slid against the ceramic ball below 300 deg. C. With further increase in the test temperature up to 400 deg. C and above, it was characterized by mild adhesion wear and plastic deformation. Since the laser cladding Ni/hBN coating registered an increased wear rate at temperatures of 600 deg. C and above, it was not suggested to be used for wear prevention and protection of the stainless steel at elevated temperature above 800 deg. C

  8. Friction and wear behavior of laser cladding Ni/hBN self-lubricating composite coating

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Shitang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Zhou Jiansong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Guo Baogang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Zhou Huidi [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Pu Yuping [Central Iron and Steel Research Institute, Beijing 100081 (China); Chen Jianmin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)], E-mail: chenjm@lzb.ac.cn

    2008-09-15

    Ni/hBN coating was successfully prepared on 1Cr18Ni9Ti stainless steel substrate by means of laser cladding. The microhardness profile of the composite coating along the depth direction was measured, while its cross-sectional microstructures and phase compositions were analyzed by means of scanning electron microscopy and X-ray diffraction. Moreover, the friction and wear behavior of the composite coatings sliding against Si{sub 3}N{sub 4} from ambient to 800 deg. C was evaluated using a ball-on-disc friction and wear tester, and the worn surface morphologies of the composite coatings and counterpart ceramic balls were observed using a scanning electron microscope. At the same time, the worn surfaces of the ceramic balls were also analyzed using a 3D non-contact surface mapping profiler as well. It was found that the laser cladding Ni/hBN coating on the stainless steel substrate had high microhardness and good friction-reducing and antiwear abilities at elevated temperatures up to 800 deg. C. The composite coating registered slightly increased friction coefficient and wear rate as the temperature rose from ambient to 100 deg. C; then the friction coefficient and wear rate decreased with increasing temperature up to 800 deg. C (with the slight increase in the wear rate at 700 deg. C and 800 deg. C to be an exception). The laser cladding Ni/hBN coating was dominated by mixed adhesion and abrasive wear as it slid against the ceramic ball below 300 deg. C. With further increase in the test temperature up to 400 deg. C and above, it was characterized by mild adhesion wear and plastic deformation. Since the laser cladding Ni/hBN coating registered an increased wear rate at temperatures of 600 deg. C and above, it was not suggested to be used for wear prevention and protection of the stainless steel at elevated temperature above 800 deg. C.

  9. Microstructure and wear behavior of austempered high carbon high silicon steel

    Directory of Open Access Journals (Sweden)

    Acharya Palaksha

    2018-01-01

    Full Text Available In the present investigation, the influence of austempering temperature and time on the microstructure and dry sliding wear behavior of high silicon steel was studied. The test specimens were initially austenitised at 900°C for 30 minutes, thereafter austempered at various temperatures 280°C, 360°C and 400°C, for varying duration from 30 to 120 minutes. These samples after austempering heat treatment were subsequently air cooled to room temperature, to generate typical ausferritic microstructures and then correlated with the wear property. The test outcomes demonstrate the slight increase in specific wear rate with increase in both austempering temperature and time. Specific wear rate was found to be minimum at an austempering temperature of 280°C, that exhibits lower bainite microstructure with high hardness, on the other hand specific wear rate was found to be slightly high at increased austempering temperatures at 360°C and 400°C, due to the upper bainite structure that offered lower hardness to the matrix. The sample austempered at 280°C for 30 minutes offered superior wear resistance when compared to other austempering conditions, mainly due to the presence of fine acicular bainitic ferrite along with stabilized retained austenite and also some martensite in the microstructure.

  10. Friction and wear behaviour of Mo–W doped carbon-based coating during boundary lubricated sliding

    International Nuclear Information System (INIS)

    Hovsepian, Papken Eh.; Mandal, Paranjayee; Ehiasarian, Arutiun P.; Sáfrán, G.; Tietema, R.; Doerwald, D.

    2016-01-01

    Graphical abstract: - Highlights: • Novel Mo–W–C coating provides extremely low friction (μ ∼ 0.03) in lubricated condition. • Mo–W–C outperforms existing DLCs in terms of low friction, independent of temperature. • Tribochemical reactions govern the wear mechanism of Mo–W–C coating. • The transfer layer contains graphitic carbon and ‘in situ’ formed WS 2 and MoS 2 . • WS 2 and MoS 2 are the key factors facilitating appreciably low friction and wear rate. - Abstract: A molybdenum and tungsten doped carbon-based coating (Mo–W–C) was developed in order to provide low friction in boundary lubricated sliding condition at ambient and at high temperature. The Mo–W–C coating showed the lowest friction coefficient among a number of commercially available state-of-the-art DLC coatings at ambient temperature. At elevated temperature (200 °C), Mo–W–C coating showed a significant reduction in friction coefficient with sliding distance in contrast to DLC coatings. Raman spectroscopy revealed the importance of combined Mo and W doping for achieving low friction at both ambient and high temperature. The significant decrease in friction and wear rate was attributed to the presence of graphitic carbon debris (from coating) and ‘in situ’ formed metal sulphides (WS 2 and MoS 2 , where metals were supplied from coating and sulphur from engine oil) in the transfer layer.

  11. Friction and wear behaviour of Mo–W doped carbon-based coating during boundary lubricated sliding

    Energy Technology Data Exchange (ETDEWEB)

    Hovsepian, Papken Eh., E-mail: p.hovsepian@shu.ac.uk [Nanotechnology Centre for PVD Research, HIPIMS Research Centre, Sheffield Hallam University, City Campus, Howard Street, Sheffield S1 1WB (United Kingdom); Mandal, Paranjayee, E-mail: 200712mum@gmail.com [Nanotechnology Centre for PVD Research, HIPIMS Research Centre, Sheffield Hallam University, City Campus, Howard Street, Sheffield S1 1WB (United Kingdom); Ehiasarian, Arutiun P., E-mail: a.ehiasarian@shu.ac.uk [Nanotechnology Centre for PVD Research, HIPIMS Research Centre, Sheffield Hallam University, City Campus, Howard Street, Sheffield S1 1WB (United Kingdom); Sáfrán, G., E-mail: safran.gyorgy@ttk.mta.hu [Institute for Technical Physics and Materials Science, Centre for Energy Research, Hungarian Academy of Sciences, H-1121 Budapest, Konkoly-Thegeut 29-33 (Hungary); Tietema, R., E-mail: rtietema@hauzer.nl [IHI Hauzer Techno Coating B.V., Van Heemskerckweg 22, 5928 LL Venlo (Netherlands); Doerwald, D., E-mail: ddoerwald@hauzer.nl [IHI Hauzer Techno Coating B.V., Van Heemskerckweg 22, 5928 LL Venlo (Netherlands)

    2016-03-15

    Graphical abstract: - Highlights: • Novel Mo–W–C coating provides extremely low friction (μ ∼ 0.03) in lubricated condition. • Mo–W–C outperforms existing DLCs in terms of low friction, independent of temperature. • Tribochemical reactions govern the wear mechanism of Mo–W–C coating. • The transfer layer contains graphitic carbon and ‘in situ’ formed WS{sub 2} and MoS{sub 2}. • WS{sub 2} and MoS{sub 2} are the key factors facilitating appreciably low friction and wear rate. - Abstract: A molybdenum and tungsten doped carbon-based coating (Mo–W–C) was developed in order to provide low friction in boundary lubricated sliding condition at ambient and at high temperature. The Mo–W–C coating showed the lowest friction coefficient among a number of commercially available state-of-the-art DLC coatings at ambient temperature. At elevated temperature (200 °C), Mo–W–C coating showed a significant reduction in friction coefficient with sliding distance in contrast to DLC coatings. Raman spectroscopy revealed the importance of combined Mo and W doping for achieving low friction at both ambient and high temperature. The significant decrease in friction and wear rate was attributed to the presence of graphitic carbon debris (from coating) and ‘in situ’ formed metal sulphides (WS{sub 2} and MoS{sub 2}, where metals were supplied from coating and sulphur from engine oil) in the transfer layer.

  12. Influence of aluminium content on the physical, mechanical and sliding wear properties of zinc-based alloys

    International Nuclear Information System (INIS)

    Prasad, B.K.; Patwardhan, A.K.; Yegneswaran, A.H.

    1997-01-01

    Attention has been focussed on the influence of Al content on the physical, mechanical and sliding wear properties of Zn-based alloys. Aspects studied include microstructure, density, electrical conductivity, hardness, tensile strength and elongation as well as sliding wear response of the alloys. Microstructural features of the alloys showed the presence of primary α, eutectic/eutectoid α + η (depending on whether the alloy was hypereutectic/hypereutectoid with regard to the concentration of Al) along with the meta stable ε phase. The study suggests that it is possible to design and develop Zn-based alloys with a wide range of concentration of Al. The alloys in turn attain different combinations of physical, mechanical and wear properties which could suit a variety of engineering applications. Increasing the Al content in the alloy system proves beneficial within limits. In other words, there exists an optimum quantity of Al which could reap its advantage to the maximum extent. This of course varies with reference to a specific property of the alloy(s). The changing response of the alloys has been explained in terms of their microstructural features and the effects produced as a result of the test conditions maintained while characterizing the specimens. (orig.)

  13. Analysis of abrasive wear behavior of PTFE composite using Taguchi’s technique

    Directory of Open Access Journals (Sweden)

    Yusuf Şahin

    2015-12-01

    Full Text Available Polymeric composites are widely used for structural, aerospace, and automobile sectors due to their good combination of high specific strength and specific modulus. These two main characteristics make these materials attractive, compared to conventional materials like metal or alloy ones. Some of their typical benefits include easy processing, corrosion resistance, low friction, and damping of noise and vibrations. Wear behavior of Polytetrafluoroethylenes (PTFE and its composites including glass-filled composites and carbon-filled composites are investigated using a pin-on-disc configuration. A plan of experiments in terms of Taguchi technique is carried out to acquire data in controlled way. An orthogonal array (L9 and the analysis of variance are employed to investigate the influence of process parameters on the wear of these composites. Volume loss increased with abrasive size, load, and distance. Furthermore, specific wear rate decreased with increasing grit size, load, sliding distance, whereas, slightly with compressive strength. Optimal process parameters, which minimize the volume loss, were the factor combinations of L1, G3, D1, and C3. Confirmation experiments were conducted to verify the optimal testing parameters. It was found that in terms of volume loss, there was a good agreement between the estimated and the experimental value of S/N ratio with an error of 1.604%. Moreover, abrasive size, load, and sliding distance exerted a great effect on the specific wear rate, at 51.14, 27.77, and 14.70%, respectively.

  14. Isotopic study of the wear of sliding bearings with plastic friction surface

    International Nuclear Information System (INIS)

    Pandur, J.; Varkonyi, A.

    1978-01-01

    A new complex device has been elaborated for the investigation of the duration of bearings in the Institute of Isotopes of the Hungarian Academy of Sciences. The simultaneous determination of wear by an isotopic method the coefficient of friction by means of a Wheatstone bridge and the bearing temperature by means of a thermoresistor is described. Dynamic loading and variable revolution per minute are applied to produce a forced wear of the bearings. The isotopically labelled wear products are removed by oil and the collected sample is measured by a scintillation detector. Wear of a steel axle in plastic housing and plastic coated axle in cast iron housing was determined. (V.N.)

  15. Effects of Material Combinations on Friction and Wear of PEEK/Steel Pairs under Oil-Lubricated Sliding Contacts

    Science.gov (United States)

    Akagaki, T.; Nakamura, T.; Hashimoto, Y.; Kawabata, M.

    2017-05-01

    The effects of material combinations on the friction and wear of PEEK/steel pairs are studied using blocks on a ring wear tester under oil-lubricated conditions. The rings are made of forged steel (SF540A) and a PEEK composite filled with 30 wt% carbon fibre. The surface roughness is 0.15 and 0.32 μm Ra, respectively. The blocks are also made of the same materials as the rings: the forged steel and the PEEK composite. Finished with an emery paper of #600, the surface roughness is 0.06 and 0.23 μm Ra, respectively. Sliding tests for 4 combinations of two materials are conducted. The load is increased up to 1177 N at 1 N s-1. The sliding velocity is varied in the range of 10 to 19 m s-1. In some cases, the ring temperature is measured with a thermocouple with a diameter of 0.5 mm, located 1 mm below the frictional surface. Results indicate that the forged steel’s ring and the PEEK composite’s block is the best combination among 4 combinations, because seizure does not occur under the increasing load up to 1177 N at the sliding velocity of 10-19 m s-1. In contrast, seizure occurs at 15 and 19 m s-1 in the other three combinations. However, the PEEK composite’s ring shows a lower friction coefficient as compared to the forged steel’s ring, when seizure does not occur. Wear scars are observed with a scanning electron microscope (SEM). The seizure mechanisms are then discussed.

  16. Friction and wear behaviour of Mo-W doped carbon-based coating during boundary lubricated sliding

    Science.gov (United States)

    Hovsepian, Papken Eh.; Mandal, Paranjayee; Ehiasarian, Arutiun P.; Sáfrán, G.; Tietema, R.; Doerwald, D.

    2016-03-01

    A molybdenum and tungsten doped carbon-based coating (Mo-W-C) was developed in order to provide low friction in boundary lubricated sliding condition at ambient and at high temperature. The Mo-W-C coating showed the lowest friction coefficient among a number of commercially available state-of-the-art DLC coatings at ambient temperature. At elevated temperature (200 °C), Mo-W-C coating showed a significant reduction in friction coefficient with sliding distance in contrast to DLC coatings. Raman spectroscopy revealed the importance of combined Mo and W doping for achieving low friction at both ambient and high temperature. The significant decrease in friction and wear rate was attributed to the presence of graphitic carbon debris (from coating) and 'in situ' formed metal sulphides (WS2 and MoS2, where metals were supplied from coating and sulphur from engine oil) in the transfer layer.

  17. Wear Behavior of an Unstable Knee: Stabilization via Implant Design?

    Directory of Open Access Journals (Sweden)

    Jörn Reinders

    2014-01-01

    Full Text Available Background. Wear-related failures and instabilities are frequent failure mechanisms of total knee replacements. High-conforming designs may provide additional stability for the joint. This study analyzes the effects of a ligamentous insufficiency on the stability and the wear behavior of a high-conforming knee design. Methods. Two simulator wear tests were performed on a high-conforming total knee replacement design. In the first, a ligamentous-stable knee replacement with a sacrificed anterior cruciate ligament was simulated. In the second, a ligamentous-unstable knee with additionally insufficient posterior cruciate ligament and medial collateral ligament was simulated. Wear was determined gravimetrically and wear particles were analyzed. Implant kinematics was recorded during simulation. Results. Significantly higher wear rates (P≤0.001 were observed for the unstable knee (14.58±0.56 mg/106 cycles compared to the stable knee (7.97 ± 0.87 mg/106 cycles. A higher number of wear particles with only small differences in wear particle characteristics were observed. Under unstable knee conditions, kinematics increased significantly for translations and rotations (P≤0.01. This increase was mainly attributed to higher tibial posterior translation and internal rotations. Conclusion. Higher kinematics under unstable test conditions is a result of insufficient stabilization via implant design. Due to the higher kinematics, increased wear was observed in this study.

  18. Tactile Sliding Behavior of R2R Mass-Produced PLLA Nanosheet towards Biomedical Device in Skin Applications

    Directory of Open Access Journals (Sweden)

    Sheng Zhang

    2018-03-01

    Full Text Available In this research, sliding friction was measured between the fingertip and nanosheet on a silicon substrate under two conditions: dry and wet. By using a force transducer, the tactile friction force and applied load were measured. According to the experimental results, the relationship of friction force and applied load exhibits a positive correlation under both dry and wet conditions. In addition, the nanosheets are able to reduce the friction force and coefficient of friction (COF compared to the reference sample, especially under the wet condition. Under the assumption of a full contact condition, the estimated contact area increases with larger applied loads. Furthermore, based on the wear observation, the skin sliding performance caused slight abrasions to the surface of the nanosheet samples with a mild wear track along the sliding direction. Overall, the sliding behavior between the skin and nanosheet was investigated in terms of friction force, COF, applied load, contact area, and wear. These findings can contribute to the nanosheet-related research towards biomedical devices in skin applications.

  19. Tribological behavior of the carbon fiber reinforced polyphenylene sulfide (PPS) composite coating under dry sliding and water lubrication

    International Nuclear Information System (INIS)

    Xu Haiyan; Feng Zhizhong; Chen Jianmin; Zhou Huidi

    2006-01-01

    Carbon fiber reinforced polyphenylene sulphide (PPS) composite coatings (the mass fraction of the carbon fiber varied from 1 to 5 wt%) were prepared by flame spraying. The microstructure and physical properties of the composite coating were studied. The friction and wear characteristics of the PPS coating and carbon fiber reinforced PPS composite coating under dry- and water-lubricated sliding against stainless steel were comparatively investigated using a block-ring tester. The composite coatings showed lower friction coefficient and higher wear rate than pure PPS coatings under dry sliding. Under water-lubricated condition, the composite coatings showed better wear resistance than under dry. Under water-lubricated condition the tribological behaviors of the 3 wt% carbon fiber reinforced composite coating also were investigated under different sliding speed and load. The result showed that the sliding speed had little effect on the tribological properties, but the load affected greatly on that of the composite coatings. The morphologies of the worn surfaces of the composite coatings and the counterpart steel were analyzed by means of scanning electron microscopy (SEM), coupled with an energy-dispersive X-ray spectrometer (EDS) for compositional analysis

  20. Microstructure and High-temperature Wear Behavior of Hot-dipped Aluminized Coating on Different Substrate Materials

    Directory of Open Access Journals (Sweden)

    ZHOU De-qin

    2018-02-01

    Full Text Available The aluminized 45 and H13 steel were prepared via hot-dipped aluminizing and subsequently high-temperature diffusion treatment. The phase, morphology and composition of aluminized coating were characterized by XRD,SEM and EDS methods. Comparative study was performed on unlubricated sliding wear behavior of plating under different substrates on a pin-on-disc wear tester, and the wear mechanism was explored. The results show that the coating is composed of ductile phases FeAl and Fe3Al. Kikendall porosity parallel to the surface exists around the interface of the two phases; because of the carbide particles agglomeration, the bond between the coating and H13 steel is apparently inferior to that in the case of 45 steel; the aluminized 45 steel possesses an excellent wear resistance under 50-200N at 400℃, whereas mild-to-severe wear transition occurs when the temperature increases to 600℃. The wear rate of the aluminized H13 steel reaches the lowest at 400℃, then slightly increases at 600℃. The wear mechanisms of Fe-Al coating are mainly predominated by oxidative mild wear, whereas the extrusion wear prevails in the process for aluminized 45 steel at 600℃.

  1. Wear behavior of pressable lithium disilicate glass ceramic.

    Science.gov (United States)

    Peng, Zhongxiao; Izzat Abdul Rahman, Muhammad; Zhang, Yu; Yin, Ling

    2016-07-01

    This article reports effects of surface preparation and contact loads on abrasive wear properties of highly aesthetic and high-strength pressable lithium disilicate glass-ceramics (LDGC). Abrasive wear testing was performed using a pin-on-disk device in which LDGC disks prepared with different surface finishes were against alumina pins at different contact loads. Coefficients of friction and wear volumes were measured as functions of initial surface finishes and contact loads. Wear-induced surface morphology changes in both LDGC disks and alumina pins were characterized using three-dimensional laser scanning microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The results show that initial surface finishes of LDGC specimens and contact loads significantly affected the friction coefficients, wear volumes and wear-induced surface roughness changes of the material. Both wear volumes and friction coefficients of LDGC increased as the load increased while surface roughness effects were complicated. For rough LDGC surfaces, three-body wear was dominant while for fine LDGC surfaces, two-body abrasive wear played a key role. Delamination, plastic deformation, and brittle fracture were observed on worn LDGC surfaces. The adhesion of LDGC matrix materials to alumina pins was also discovered. This research has advanced our understanding of the abrasive wear behavior of LDGC and will provide guidelines for better utilization and preparation of the material for long-term success in dental restorations. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 968-978, 2016. © 2015 Wiley Periodicals, Inc.

  2. Dry sliding wear of Al-Fe-Cr-Mn quasicrystalline phase former alloy obtained by spray forming; Estudo do comportamento ao desgaste de liga Al-Fe-Cr-Mn obtida por conformacao por spray

    Energy Technology Data Exchange (ETDEWEB)

    Yamasaki, S.M.T.; Rios, C.T.; Botta Filho, W.J.; Bolfarini, C.; Kiminami, C.S. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais; Gargarella, P.; Mendes, M.A.B., E-mail: marcio.andreato@gmail.co [Universidade Federal de Sao Carlos (PPG-CEMUFSCar), SP (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais

    2010-07-01

    Samples from different regions of a spray formed billet of Al{sub 92}Fe{sub 3}Cr{sub 2}Mn{sub 3} quasicrystalline phase former alloy were analyzed and their wear behavior has been studied. The microstructures observed depend on the cooling rate imposed to the material. The border of the billet exhibits a very fine structure with presence of quasicrystalline phase and the base showed a fine structure but without presence of quasicrystalline phase. Dry sliding wear tests were made using three loads and samples of these two different regions. The wear surfaces were analyzed by scanning electron microscopy and X-ray diffraction. Similar wear behavior was observed in the border and the base samples at the same load. The wear mechanism verified is the adhesive and the applied load increases the formation of Al{sub 2}O{sub 3}. These particles can take off the surface and act as abrasive, which can explain the large increase in the wear rate for the samples loaded at 30N.(author)

  3. Microstructural and Wear Behavior Characterization of Porous Layers Produced by Pulsed Laser Irradiation in Glass-Ceramics Substrates.

    Science.gov (United States)

    Sola, Daniel; Conde, Ana; García, Iñaki; Gracia-Escosa, Elena; de Damborenea, Juan J; Peña, Jose I

    2013-09-09

    In this work, wear behavior and microstructural characterization of porous layers produced in glass-ceramic substrates by pulsed laser irradiation in the nanosecond range are studied under unidirectional sliding conditions against AISI316 and corundum counterbodies. Depending on the optical configuration of the laser beam and on the working parameters, the local temperature and pressure applied over the interaction zone can generate a porous glass-ceramic layer. Material transference from the ball to the porous glass-ceramic layer was observed in the wear tests carried out against the AISI316 ball counterface whereas, in the case of the corundum ball, the wear volume loss was concentrated in the porous layer. Wear rate and friction coefficient presented higher values than expected for dense glass-ceramics.

  4. Microstructural and Wear Behavior Characterization of Porous Layers Produced by Pulsed Laser Irradiation in Glass-Ceramics Substrates

    Directory of Open Access Journals (Sweden)

    Jose I. Peña

    2013-09-01

    Full Text Available In this work, wear behavior and microstructural characterization of porous layers produced in glass-ceramic substrates by pulsed laser irradiation in the nanosecond range are studied under unidirectional sliding conditions against AISI316 and corundum counterbodies. Depending on the optical configuration of the laser beam and on the working parameters, the local temperature and pressure applied over the interaction zone can generate a porous glass-ceramic layer. Material transference from the ball to the porous glass-ceramic layer was observed in the wear tests carried out against the AISI316 ball counterface whereas, in the case of the corundum ball, the wear volume loss was concentrated in the porous layer. Wear rate and friction coefficient presented higher values than expected for dense glass-ceramics.

  5. A new reciprocating sliding wear testing apparatus for high temperature gaseous environments

    International Nuclear Information System (INIS)

    Smith, A.F.; Radford, T.J.; Mawson, D.; Kaye, P.

    1988-01-01

    A new reciprocating wear testing rig is described that has been designed, built and commissioned at the Berkeley Nuclear Laboratories, United Kingdom. The objectives of this work are to improve upon the range of parameters offered by the existing rigs and to provide additional facilities for data acquisition and analysis. (author)

  6. New reciprocating sliding wear testing apparatus for high temperature gaseous environments

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.F.; Radford, T.J.; Mawson, D.; Kaye, P.

    1988-09-01

    A new reciprocating wear testing rig is described that has been designed, built and commissioned at the Berkeley Nuclear Laboratories, United Kingdom. The objectives of this work are to improve upon the range of parameters offered by the existing rigs and to provide additional facilities for data acquisition and analysis.

  7. A comparative study of tribological behavior of plasma and D-gun sprayed coatings under different wear modes

    International Nuclear Information System (INIS)

    Sundararajan, G.; Rao, D.S.; Prasad, K.U.M.; Joshi, S.V.

    1998-01-01

    In recent years, thermal sprayed protective coatings have gained widespread acceptance for a variety of industrial applications. A vast majority of these applications involve the use of thermal sprayed coatings to combat wear. While plasma spraying is the most versatile variant of all the thermal spray processes, the detonation gun (D-gun) coatings have been a novelty until recently because of their proprietary nature. The present study is aimed at comparing the tribological behavior of coatings deposited using the two above techniques by focusing on some popular coating materials that are widely adopted for wear resistant applications, namely, WC-12% Co, Al 2 O 3 , and Cr 3 C 2 -NiCr. To enable a comprehensive comparison of the above indicated thermal spray techniques as well as coating materials, the deposited coatings were extensively characterized employing microstructural evaluation, microhardness measurements, and XRD analysis for phase constitution. The behavior of these coatings under different wear modes was also evaluated by determining their tribological performance when subjected to solid particle erosion tests, rubber wheel sand abrasion tests, and pin-on-disk sliding wear tests. Among all the coating materials studied, D-gun sprayed WC-12% Co, in general, yields the best performance under different modes of wear, whereas plasma sprayed Al 2 O 3 shows least wear resistance to every wear mode

  8. Friction and wear behavior of steam-oxidized ferrous PM compacts

    Energy Technology Data Exchange (ETDEWEB)

    Raj, P. Philomen-D-Anaand; GopalaKrishna, A. [Dept. of Mechanical Engineering, Jawaharlal Nehru Technological University, Kakinada (India); Palaniradja, K [Dept. of Mechanical Engineering, Pondicherry Engineering College, Pondicherry (India)

    2016-10-15

    This study determines density effect by assessing sintering temperature and graphite content on the dry sliding wear characteristics of steam-treated iron materials using a pin-on-disk wear test. The specimens were prepared from atomized premixed iron base powders and contained 0.1 to 1.0 wt.% carbon compacted at different densities (5.9 g/cc to 6.8 g/cc). The specimens were sintered for 1 h at different sintering temperatures (1090°C to 1130°C), and then subjected to continuous steam treatment at 540°C for 95 min through in situ Powder metallurgy (PM) technique. Steam treatment was proposed to improve the wear performances of the components of PM. Wear tests were conducted using a pin-on-disk-type machine. Load ranged from 20 N to 60 N. Sliding distance and sliding velocity of 312 m and 0.26 m/s, respectively, were adopted for all tests. Scanning electron microscope was used to analyze wear surface. Increased density and graphite content reduced the wear rate of steam-treated materials. Hardness increased with increasing graphite content. Wear mechanism, wear rate map, and wear maps were drawn for the test result data. Wear transition map identified mild, severe, and ultra-severe wear regimes as functions of applied load.

  9. Sliding wear studies of microwave clad versus unclad surface of stainless steel 304

    Directory of Open Access Journals (Sweden)

    Akshata M. K.

    2018-01-01

    Full Text Available Small and large scale (gas power plant, hydro power plant, automobile industries are suffering by failure of component. Sometimes, it is also observed that the component which was failed due to these reasons are very much costly and replacement of those also very difficult due to the complex geometry. By using Microwave hybrid heating, WC-12Co based clads were developed on austenitic stainless steel (SS304. Microwave clads were developed by introducing the preplaced, preheated powder for a duration of 15 min to microwave radiation at 2.45GHz frequency and 900 W power in domestic microwave applicator. By using optical microscope and scanning electron microscope (SEM, the developed clads were characterized. By using pin-on-disk, wear performance of the WC-12Co based clads and unclad samples were tested. It is observed that developed clad samples performed superior wear resistance than unclad samples.

  10. Effect of Load on Friction-Wear Behavior of HVOF-Sprayed WC-12Co Coatings

    Science.gov (United States)

    Yifu, Jin; Weicheng, Kong; Tianyuan, Sheng; Ruihong, Zhang; Dejun, Kong

    2017-07-01

    A WC-12Co coating was sprayed on AISI H13 hot work mold steel using a high-velocity oxygen fuel. The morphologies, phase compositions, and distributions of chemical elements of the obtained coatings were analyzed using a field emission scanning electron microscope, x-ray diffraction, and energy-dispersive spectroscope (EDS), respectively. The friction-wear behaviors under different loads were investigated using a reciprocating wear tester; the morphologies and distributions of the chemical elements of worn tracks were analyzed using a SEM and its configured EDS, respectively. The results show the reunited grains of WC are held together by the Co binder; the primary phases of the coating are WC, Co, and a small amount of W2C and W, owing to the oxidation and decarburization of WC. Inter-diffusion of Fe and W between the coating and the substrate is shown, which indicates a good coating adhesion. The values of the average coefficient of friction under the loads of 40, 80, and 120 N are 0.29, 0.31, and 0.49, respectively. The WC grains are pulled out of the coating during the sliding wear test, but the coating maintains its integrity, suggesting that the coating is intact and continuously protects the substrate from wearing.

  11. Microstructure and sliding wear properties of HVOF sprayed, laser remelted and laser clad Stellite 6 coatings

    Czech Academy of Sciences Publication Activity Database

    Houdková, Š.; Pala, Zdeněk; Smazalová, E.; Vostřák, M.; Česánek, Z.

    2017-01-01

    Roč. 318, May (2017), s. 129-141 ISSN 0257-8972. [International Meeting on Thermal Spraying (RIPT)/7./. Limoges, 09.12.2015-11.12.2015] Institutional support: RVO:61389021 Keywords : Stellite 6 * HVOF * Laser remelting * Laser clad * Wear * Phase transformation Subject RIV: JK - Corrosion ; Surface Treatment of Materials OBOR OECD: Coating and films Impact factor: 2.589, year: 2016 http://www.sciencedirect.com/science/ article /pii/S0257897216308817

  12. Dry Sliding Wear Charactristics of Aluminum 6061-T6, Magnesium AZ31 and Rock Dust Composite

    Science.gov (United States)

    Balachandar, R.; Balasundaram, R.; Rajkumar, G.

    2018-02-01

    In recent years, the use of aluminum composite is gaining popularity in a wide range of applications like automobiles, aerospace and constructions (both interior & exterior) panels etc., due to its high strength, low density characteristics. Various reinforcing materials are used with aluminum 6061-T6 in order to have better mechanical properties. The addition of 0.3% of magnesium AZ31 will increase the ultimate tensile strength by 25 %. The reinforcement of rock dust will decrease the density. Hence, in order to have an advantages of magnesium AZ31 and rock dust, in this work, these two constitutes are varied from 1% to 2% on the base material of Al6061-T6 in stir casting. To evaluate the wear characteristics, Pin on disc is used in these composites. The input parameters are speed, time & load. The output response is wear. To minimize the number of experiments, L9 orthogonal array is used. The test results showed that a composite of 97% of Al (6061-T6), 1% Mg (AZ31) & 2 % of rock dust produced less wear. To find the best value of operating parameter for each sample, ANN-GA is used.

  13. Microstructure and surface chemistry of amorphous alloys important to their friction and wear behavior

    Science.gov (United States)

    Miyoshi, K.; Buckley, D. H.

    1986-01-01

    An investigation was conducted to examine the microstructure and surface chemistry of amorphous alloys, and their effects on tribological behavior. The results indicate that the surface oxide layers present on amorphous alloys are effective in providing low friction and a protective film against wear in air. Clustering and crystallization in amorphous alloys can be enhanced as a result of plastic flow during the sliding process at a low sliding velocity, at room temperature. Clusters or crystallines with sizes to 150 nm and a diffused honeycomb-shaped structure are produced on sizes to 150 nm and a diffused honeycomb-shaped structure are produced on the wear surface. Temperature effects lead to drastic changes in surface chemistry and friction behavior of the alloys at temperatures to 750 C. Contaminants can come from the bulk of the alloys to the surface upon heating and impart to the surface oxides at 350 C and boron nitride above 500 C. The oxides increase friction while the boron nitride reduces friction drastically in vacuum.

  14. Friction and wear behavior of glasses and ceramics

    Science.gov (United States)

    Buckley, D. H.

    1973-01-01

    Adhesion, friction, and wear behavior of glasses and ionic solids are reviewed. These materials are shown to behave in a manner similar to other solids with respect to adhesion. Their friction characteristics are shown to be sensitive to environmental constituents and surface films. This sensitivity can be related to a reduction in adhesive bonding and the changes in surficial mechanical behavior associated with Rehbinder and Joffe effects. Both friction and wear properties of ionic crystalline solids are highly anisotropic. With metals in contact with ionic solids the fracture strength of the ionic solid and the shear strength in the metal and those properties that determine these will dictate which of the materials undergoes adhesive wear. The chemical activity of the metal plays an important role in the nature and strength of the adhesive interfacial bond that develops between the metal and a glass or ionic solid.

  15. Sliding-wear resistance of pure near fully-dense B4C under lubrication with water, diesel fuel, and paraffin oil

    DEFF Research Database (Denmark)

    Ortiz, Angel L.; Leal, Victor Manuel Candelario; Borrero-López, Oscar

    2017-01-01

    The sliding-wear resistance of pure near fully-dense B4C is investigated, and the wear mode/mechanisms identified, under lubrication with water, diesel fuel, and paraffin oil. It is found that the wear is mild in the three cases, with specific wear rates (SWRs) of 10−16–10−17 m3/N m. Nonetheless......, the wear resistance of the B4C ceramic is one order of magnitude greater under oil lubrication (1016 N m/m3) than under water lubrication (1015 N m/m3), and twice as great for the specific case of paraffin oil than diesel fuel, attributable to the lubricant’s viscosity. It is also found that the wear mode...... is always abrasion, and that the wear mechanisms are plastic deformation and localized fracture with grain pullout. However, in agreement with the macro-wear data, the severity of the wear damage is lower under lubrication with paraffin oil, followed by diesel fuel, and lastly water. Finally...

  16. Statistical model to predict dry sliding wear behaviour of Aluminium-Jute bast ash particulate composite produced by stir-casting

    Directory of Open Access Journals (Sweden)

    Gambo Anthony VICTOR

    2017-06-01

    Full Text Available A model to predict the dry sliding wear behaviour of Aluminium-Jute bast ash particulate composites produced by double stir-casting method was developed in terms of weight fraction of jute bast ash (JBA. Experiments were designed on the basis of the Design of Experiments (DOE technique. A 2k factorial, where k is the number of variables, with central composite second-order rotatable design was used to improve the reliability of results and to reduce the size of experimentation without loss of accuracy. The factors considered in this study were sliding velocity, sliding distance, normal load and mass fraction of JBA reinforcement in the matrix. The developed regression model was validated by statistical software MINITAB-R14 and statistical tool such as analysis of variance (ANOVA. It was found that the developed regression model could be effectively used to predict the wear rate at 95% confidence level. The wear rate of cast Al-JBAp composite decreased with an increase in the mass fraction of JBA and increased with an increase of the sliding velocity, sliding distance and normal load acting on the composite specimen.

  17. Sliding Wear Behaviour and Corosion Resistance to Ringer’s Solution of Uncoated and DLC Coated X46Cr13 Steel

    Directory of Open Access Journals (Sweden)

    Scendo M.

    2016-12-01

    Full Text Available Sliding wear properties and corrosion resistance in Ringer’s solution of uncoated and diamond-like carbon (DLC coated X46Cr13 steel was tested. The Raman spectra showed that the DLC film was successfully coated by plasma assisted CVD method onto the steel surface. The wear test, carried out using a ball-on disk tribometer, revealed that the DLC coating show better resistance to sliding wear and lower friction coefficient against a 100Cr6 steel ball than five times softer X46Cr13 steel. The oxidation kinetic parameters were determined by means of both the gravimetric and electrochemical method. It was found that the DLC coating markedly decreased the rate of corrosion of the X46Cr13 steel, irrespective of the corrosion mechanism involved.

  18. Thermal hydraulic behavior of SCWR sliding pressure startup

    International Nuclear Information System (INIS)

    Fu Shengwei; Zhou Chong; Xu Zhihong; Yang Yanhua

    2011-01-01

    The modification to ATHLET-SC code is introduced in this paper, which realizes the simulation of trans-critical transients using two-phase model. With the modified code, the thermal-hydraulic dynamic behavior of the mixed SCWR core during the startup process is simulated. The startup process is similar to the design of SCLWR-H sliding pressure startup. The results show that maximum temperature of cladding-surface does not exceed 650℃ in the whole startup process, and the sudden change of water properties in the trans-critical transients will not cause harmful influence to the heat transfer of the fuel cladding. (authors)

  19. Friction and wear behavior of nanosilica-filled epoxy resin composite coatings

    International Nuclear Information System (INIS)

    Kang Yingke; Chen Xinhua; Song Shiyong; Yu Laigui; Zhang Pingyu

    2012-01-01

    Hydrophilic silica nanoparticles (abridged as nano-SiO 2 ) surface-capped with epoxide were dispersed in the solution of epoxy resin (abridged as EP) in tetrahydrofuran under magnetic stirring. Resultant suspension of nano-SiO 2 in EP was then coated onto the surface of glass slides and dried at 80 °C in a vacuum oven for 2 h, generating epoxy resin-nanosilica composite coatings (coded as EP/nano-SiO 2 ). EP coating without nano-SiO 2 was also prepared as a reference in the same manner. A water contact angle meter and a surface profiler were separately performed to measure the water contact angles and surface roughness of as-prepared EP/nano-SiO 2 composite coatings. The friction and wear behavior of as-prepared EP/nano-SiO 2 composite coatings sliding against steel in a ball-on-plate contact configuration under unlubricated condition was evaluated. Particularly, the effect of coating composition on the friction and wear behavior of the composite coatings was highlighted in relation to their microstructure and worn surface morphology examined by means of scanning electron microscopy. Results indicate that EP/nano-SiO 2 composite coatings have a higher surface roughness and water contact angle than EP coating. The EP-SiO 2 coatings doped with a proper amount of hydrophilic SiO 2 nanoparticles show lower friction coefficient than EP coating. However, the introduction of surface-capped nanosilica as the filler results in inconsistent change in the friction coefficient and wear rate of the filled EP-matrix composites; and it needs further study to achieve well balanced friction-reducing and antiwear abilities of the composite coatings for tribological applications.

  20. Wear surface damage of a Stainless Steel EN 3358 aeronautical component subjected to sliding

    Directory of Open Access Journals (Sweden)

    Ferdinando Felli

    2013-01-01

    Full Text Available The present paper describes the failure analysis of an aircraft component subjected to several episodes of in service failure, resulted in loss of the aircraft safety. Modern aircrafts are provided with mechanical systems which have the task to open not pressurized hatches during landing. The components of such systems are subject to considerable mechanical stresses in harsh environment (presence of moisture and pollutants, significant and sudden temperature variations. The system is constituted by a sliding piston, a related nipple and by a locking system consisting of 4 steel spheres which are forced into a countersink machined on the piston when the hatches is open. The whole system is activated by a preloaded spring. The machined parts, nipple and piston, are made of EN3358 steel (X3CrNiMo13-8-2, a precipitation hardening stainless steel with very low content of carbon often used in the aerospace. The samples provided by the manufacturer present different types of damage all referable to phenomena relative to the sliding of the piston inside the nipple. The present paper describes the different damage observed and the microstructure of the material, then are reported the results obtained from the characterization of the material of the samples by means of optical and electronic microscopy, carried out to define the mechanisms involved in the system seizure. In order to define the primary cause of failure and to propose solutions to be adopted, also analyzing the criticality of using this PH stainless steel for this application, the results of different tests were compared with system design and working data.

  1. How patient-selected colors for removable appliances are reflected in electronically tracked compliance (wear times and wear behavior).

    Science.gov (United States)

    Schott, Timm C; Menne, Dieter

    2018-03-27

    A broad spectrum of colors for removable appliances, intended to optimize acceptance of treatment and patient cooperation, have been available on the dental market for years. This is the first study to analyze how patient-selected colors are reflected in wear times and wear behavior of removable appliances. The study included 117 children (55 girls and 62 boys) who were treated with active removable plate or functional appliances. All patients were offered to choose from 11 different colors, which were pooled into six groups (black, blue, green, yellow, pink, red) for analysis, or to combine any two to four colors ("multicolored" group) for their appliances. All appliances featured a built-in microsensor (TheraMon; MC Technology, Hargelsberg, Austria) for objective wear-time tracking. Differences between wear times were analyzed using pairwise t tests and Tukey correction. The longest median wear times were recorded in the blue and green groups (≈11 h/d) and the shortest ones in the red and pink groups (≈9 h/d), but they were not significantly influenced by the patient-selected colors. The median wear times involved an age-related decrease by 0.56 h/y that was statistically significant ( P = .00005). No gender-specific patterns of wear behavior were observed. Patient-selected colors for removable appliances can presumably improve acceptance of treatment, but they are not associated with statistically significant improvements in wear time or wear behavior.

  2. Wear-resistant powder materials with intermetallic hardening. I. Nonporous materials for antifriction purposes

    Energy Technology Data Exchange (ETDEWEB)

    Karapetyan, G.K.; Akopov, N.L.; Karapetyan, F.K.; Manukyan, N.N.

    1987-09-01

    This article investigates the wear resistance, microhardness, microstructure, and crystal-phase behavior of a molybdenum alloy solid lubricant under cyclic wear and sliding friction tests against steel 45. Calculated and experimental results are given.

  3. Microstructural and superficial modification in a Cu-Al-Be shape memory alloy due to superficial severe plastic deformation under sliding wear conditions

    Science.gov (United States)

    Figueroa, C. G.; Garcia-Castillo, F. N.; Jacobo, V. H.; Cortés-Pérez, J.; Schouwenaars, R.

    2017-05-01

    Stress induced martensitic transformation in copper-based shape memory alloys has been studied mainly in monocrystals. This limits the use of such results for practical applications as most engineering applications use polycristals. In the present work, a coaxial tribometer developed by the authors was used to characterise the tribological behaviour of polycrystalline Cu-11.5%Al-0.5%Be shape memory alloy in contact with AISI 9840 steel under sliding wear conditions. The surface and microstructure characterization of the worn material was conducted by conventional scanning electron microscopy and atomic force microscopy, while the mechanical properties along the transversal section were measured by means of micro-hardness testing. The tribological behaviour of Cu-Al-Be showed to be optimal under sliding wear conditions since the surface only presented a slight damage consisting in some elongated flakes produced by strong plastic deformation. The combination of the plastically modified surface and the effects of mechanically induced martensitic transformation is well-suited for sliding wear conditions since the modified surface provides the necessary strength to avoid superficial damage while superelasticity associated to martensitic transformation is an additional mechanism which allows absorbing mechanical energy associated to wear phenomena as opposed to conventional ductile alloys where severe plastic deformation affects several tens of micrometres below the surface.

  4. Comparison of friction and wear performances of brake materials containing different amounts of ZrSiO4 dry sliding against SiCp reinforced Al matrix composites

    International Nuclear Information System (INIS)

    Zhang Shaoyang; Wang Fuping

    2007-01-01

    Low friction levels for brake materials dry sliding against Al matrix composites (Al-MMCs) were observed. Al matrix composites reinforced with 30 vol.% SiC p (34 μm) were used first to fabricate a new brake drum in place of the conventional cast iron brake drum for a Chase Machine. Experimental studies on the brake materials differing in amounts of zirconium silicate (0 wt%, 4 wt%, 8 wt%, and 12 wt% ZrSiO 4 ) dry sliding against the Al-MMCs drum were performed on the Chase Machine in order to examine their effects on friction and wear performances. The test procedures include friction fade and recovery, load and speed sensitivities at 177 deg. C and 316 deg. C, and wear. Experimental results show that the brake material containing 8 wt% ZrSiO 4 had the best wear resistance and higher friction level. The brake material containing 12 wt% ZrSiO 4 had the highest friction level, but wear increased rapidly. The deterioration of the latter wear suggests that this brake material is unreliable in commercial applications

  5. Influence of load and sliding velocity on wear resistance of solid-lubricant composites of ultra-high molecular weight polyethylene

    Science.gov (United States)

    Panin, S. V.; Kornienko, L. A.; Buslovich, D. G.; Alexenko, V. O.; Ivanova, L. R.

    2017-12-01

    To determine the limits of the operation loading intervals appropriate for the use of solid lubricant UHMWPE composites in tribounits for mechanical engineering and medicine, the tribotechnical properties of UHMWPE blends with the optimum solid lubricant filler content (polytetrafluoroethylene, calcium stearate, molybdenum disulfide, colloidal graphite, boron nitride) are studied under dry sliding friction at different velocities (V = 0.3 and 0.5 m/s) and loads (P = 60 and 140 N). It is shown that the wear resistance of solid lubricant UHMWPE composites at moderate sliding velocities (V = 0.3 m/s) and loads (P = 60 N) increases 2-3 times in comparison with pure UHMWPE, while at high load P = 140 N wear resistance of both neat UHMWPE and its composites is reduced almost twice. At high sliding velocities and loads (up to P = 140 N), multiple increasing of the wear of pure UHMWPE and its composites takes place (by the factor of 5 to 10). The operational conditions of UHMWPE composites in tribounits in engineering and medicine are discussed.

  6. Optimization of wear behavior of electroless Ni-P-W coating under dry and lubricated conditions using genetic algorithm (GA

    Directory of Open Access Journals (Sweden)

    Arkadeb Mukhopadhyay

    2016-12-01

    Full Text Available The present study aims to investigate the tribological behavior of Ni-P-W coating under dry and lubricated condition. The coating is deposited onto mild steel (AISI 1040 specimens by the electroless method using a sodium hypophosphite based alkaline bath. Coating characterization is done to investigate the effect of microstructure on its performance. The change in microhardness is observed to be quite significant after annealing the deposits at 400°C for 1h. A pin–on–disc type tribo-tester is used to investigate the tribological behavior of the coating under dry and lubricated conditions. The experimental design formulation is based on Taguchi’s orthogonal array. The design parameters considered are the applied normal load, sliding speed and sliding duration while the response parameter is wear depth. Multiple regression analysis is employed to obtain a quadratic model of the response variables with the main design parameters under considerations. A high value of coefficient of determination of 95.3% and 87.5% of wear depth is obtained under dry and lubricated conditions, respectively which indicate good correlation between experimental results and the multiple regression models. Analysis of variance at a confidence level of 95% shows that the models are statistically significant. Finally, the quadratic equations are used as objective functions to obtain the optimal combination of tribo testing parameters for minimum wear depth using genetic algorithm (GA.

  7. Friction and wear behavior of nitrogen-doped ZnO thin films deposited via MOCVD under dry contact

    Directory of Open Access Journals (Sweden)

    U.S. Mbamara

    2016-06-01

    Full Text Available Most researches on doped ZnO thin films are tilted toward their applications in optoelectronics and semiconductor devices. Research on their tribological properties is still unfolding. In this work, nitrogen-doped ZnO thin films were deposited on 304 L stainless steel substrate from a combination of zinc acetate and ammonium acetate precursor by MOCVD technique. Compositional and structural studies of the films were done using Rutherford Backscattering Spectroscopy (RBS and X-ray Diffraction (XRD. The frictional behavior of the thin film coatings was evaluated using a ball-on-flat configuration in reciprocating sliding under dry contact condition. After friction test, the flat and ball counter-face surfaces were examined to assess the wear dimension and failure mechanism. Both friction behavior and wear (in the ball counter-face were observed to be dependent on the crystallinity and thickness of the thin film coatings.

  8. Wear behavior of steam generator tubes in nuclear power plant operating condition

    International Nuclear Information System (INIS)

    Kim, In-Sup; Hong, Jin-Ki; Kim, Hyung-Nam; Jang, Ki-Sang

    2003-01-01

    Reciprocating sliding wear tests were performed on steam generator tubes materials at steam generator operating temperature. The material surfaces react with oxygen to form oxides. The oxide properties such as formation rate and mechanical properties are varied with the test temperature and alloy composition. So, it is important to investigate the wear properties of each steam generator tube materials in steam generator operating condition. The tests results indicated that the wear coefficient in work rate model of alloy 690 was faster than that of alloy 800. From the scanning electron microscopy observation, the wear scars were similar each other and worn surfaces were covered with oxide layers. It seemed that the oxide layers were formed by wear debris sintering or cold welding and these layer properties affected the wear rate of steam generator tube materials. (author)

  9. Influence of Ultrasonic Surface Rolling on Microstructure and Wear Behavior of Selective Laser Melted Ti-6Al-4V Alloy

    Directory of Open Access Journals (Sweden)

    Zhen Wang

    2017-10-01

    Full Text Available The present article studied the effect of ultrasonic surface rolling process (USRP on the microstructure and wear behavior of a selective laser melted Ti-6Al-4V alloy. Surface characteristics were investigated using optical microscope, nano-indentation, scanning electron microscope, transmission electron microscope and laser scanning confocal microscope. Results indicated that the thickness of pore-free surfaces increased to 100~200 μm with the increasing ultrasonic surface rolling numbers. Severe work hardening occurred in the densified layer, resulting in the formation of refined grains, dislocation walls and deformation twins. After 1000 N 6 passes, about 15.5% and 14.1% increment in surficial Nano-hardness and Vickers-hardness was obtained, respectively. The hardness decreased gradually from the top surface to the substrate. Wear tests revealed that the friction coefficient declined from 0.74 (polished surface to 0.64 (USRP treated surface and the wear volume reduced from 0.205 mm−3 to 0.195 mm−3. The difference in wear volume between USRP treated and polished samples increased with sliding time. The enhanced wear resistance was concluded to be associated with the improvement of hardness and shear resistance and also the inhibition of delamination initiation.

  10. Sliding behaviors of elastic cylindrical tanks under seismic loading

    International Nuclear Information System (INIS)

    Kobayashi, N.

    1993-01-01

    There is a paper that reports on the occurrence of sliding in several oil tanks on Alaskan earthquake of 1964. This incident appears to be in need of further investigation for the following reasons: First, in usual seismic designing of cylindrical tanks ('tanks'), sliding is considered to occur when the lateral inertial force exceeds the static friction force. When the tank in question can be taken as a rigid body, this rule is known to hold true. If the tank is capable of undergoing a considerable amount of elastic deformation, however, its applicability has not been proved. Second, although several studies have been done on the critical conditions for static sliding the present author is unaware of like ones made on the dynamic sliding, except for the pioneering work of Sogabe, in which they have empirically indicated possibility of sliding to occur under the force of sloshing. Third, this author has shown earlier on that tanks, if not anchored properly, will start rocking, inducing uplifting of the base plate, even at a relatively small seismic acceleration of 10 gal or so. The present study has been conducted with these observations for the background. Namely, based on a notion that elastic deformation given rise to by rocking oscillation should be incorporated as an important factor in any set of critical conditions for the onset of sliding, a series of shaking table experiments were performed for rigid steel block to represent the rigid tanks ('rigid model') and a model tank having a same sort of plate thickness-to-diameter ratio as industrial tanks to represent the elastic cylindrical tanks ('elastic model'). Following observations have been obtained for the critical condition of the onset of sliding: (1) sliding of rigid tanks will occur when the lateral force given rise to by oscillation exceeds the static, or the Coulombic, friction force. (2) if vertical oscillation is imposed on the lateral oscillation, the lateral force needed to induce sliding of a

  11. Mechanical behavior and wear prediction of stir cast Al–TiB2 composites using response surface methodology

    International Nuclear Information System (INIS)

    Suresh, S.; Shenbaga Vinayaga Moorthi, N.; Vettivel, S.C.; Selvakumar, N.

    2014-01-01

    Graphical abstract: - Highlights: • Various experiments were conducted on Al6061–TiB 2 composite. • XRD and EDS studies confirm the crystalline size and elements present. • SEM, EDS and OM observations were used to study the characteristics. • Curve fitting and RSM design methods are effectively used to develop the model. - Abstract: Al6061 was reinforced with various percentages of TiB 2 particles by using high energy stir casting method. The characterization was performed through X-ray Diffraction, Energy Dispersive Spectrum and Scanning Electron Microscope. The mechanical behaviors such as hardness, tensile strength and tribological behavior were investigated. Wear experiments were conducted by using a pin-on-disc wear tester at varying load. The curve fitting technique was used to develop the respective polynomial and power law equations. The wear mechanism of the specimen was studied through SEM. Response Surface Methodology was used to minimize the number of experimental conditions and develop the mathematical models between the key process parameters namely weight percentage of TiB 2 , load and sliding distance. Analysis of Variance technique was applied to check the validity of the developed model. The mathematical model developed for the specific wear rate was predicted at 99.5% confidence level and some useful conclusions were made

  12. Wear resistance and structural changes in nitrogen-containing high-chromium martensitic steels under conditions of abrasive wear and sliding friction

    International Nuclear Information System (INIS)

    Makarov, A.V.; Korshunov, L.G.; Schastlivtsev, V.M.; Chernenko, N.L.

    1998-01-01

    Martensitic nitrogen-containing steels Kh17N2A0.14, Kh13A0.14, Kh14G4A0.22 as well as steel 20Kh13 were studied for their wear resistance under conditions of friction and abrasion. Metallography, X ray diffraction analysis and electron microscopy were used to investigate the structural changes taking place in a thin surface layer on wearing. It is shown that an increase of nitrogen content of 0.14 to 0.22% promotes an enhancement of steel resistance to abrasive and adhesive wear, especially after tempering in the range of 500-550 deg C. Typically, the nitrogen-containing steels exhibit lower resistance to various types of wear in comparison with the steels with high-carbon martensite due to their lower deformability under conditions of friction loading

  13. Anisotropy abrasive wear behavior of bagasse fiber reinforced ...

    African Journals Online (AJOL)

    parallel orientation (APO) and normal orientation (NO) by using a two body abrasion wear tester. Three different types of abrasives wear behaviour have been observed in the composite in three orientations and follow the following trends: WNO ...

  14. Fretting Wear Behaviors of Aluminum Cable Steel Reinforced (ACSR Conductors in High-Voltage Transmission Line

    Directory of Open Access Journals (Sweden)

    Xingchi Ma

    2017-09-01

    Full Text Available This work reports the fretting wear behavior of aluminum cable steel reinforced (ACSR conductors for use in high-voltage transmission line. Fretting wear tests of Al wires were conducted on a servo-controlled fatigue testing machine with self-made assistant apparatus, and their fretting process characteristics, friction force, wear damage, and wear surface morphology were detailed analyzed. The results show that the running regime of Al wires changes from a gross slip regime to a mixed regime more quickly as increasing contact load. With increasing amplitudes, gross slip regimes are more dominant under contact loads of lower than 30 N. The maximum friction force is relatively smaller in the NaCl solution than in a dry friction environment. The primary wear mechanisms in dry friction environments are abrasive wear and adhesive wear whereas abrasive wear and fatigue damage are dominant in NaCl solution.

  15. Investigation on the Tribological Behavior and Wear Mechanism of Five Different Veneering Porcelains.

    Directory of Open Access Journals (Sweden)

    Jie Min

    Full Text Available The primary aim of this research was to investigate the wear behavior and wear mechanism of five different veneering porcelains.Five kinds of veneering porcelains were selected in this research. The surface microhardness of all the samples was measured with a microhardness tester. Wear tests were performed on a ball-on-flat PLINT fretting wear machine, with lubrication of artificial saliva at 37°C. The friction coefficients were recorded by the testing system. The microstructure features, wear volume, and damage morphologies were recorded and analyzed with a confocal laser scanning microscope and a scanning electron microscope. The wear mechanism was then elucidated.The friction coefficients of the five veneering porcelains differ significantly. No significant correlation between hardness and wear volume was found for these veneering porcelains. Under lubrication of artificial saliva, the porcelain with higher leucite crystal content exhibited greater wear resistance. Additionally, leucite crystal size and distribution in glass matrix influenced wear behavior. The wear mechanisms for these porcelains were similar: abrasive wear dominates the early stage, whereas delamination was the main damage mode at the later stage. Furthermore, delamination was more prominent for porcelains with larger crystal sizes.Wear compatibility between porcelain and natural teeth is important for dental restorative materials. Investigation on crystal content, size, and distribution in glass matrix can provide insight for the selection of dental porcelains in clinical settings.

  16. A kinetic model for impact/sliding wear of pressurized water reactor internal components: Application to rod cluster control assemblies

    International Nuclear Information System (INIS)

    Zbinden, M.

    1996-01-01

    Certain internal components of Pressurized Water Reactors are damaged by wear when subjected to vibration induced by flow. In order to enable predictive calculation of such wear, one must have a model which takes account reliably of real damages. The modelling of wear represents a final link in a succession of numerical calculations which begins by the determination of hydraulic excitations induced by the flow. One proceeds, then, in the dynamic response calculation of the structure to finish up with an estimation of volumetric wear and of the depth of wear scars. A new concept of industrial wear model adapted to components of nuclear plants is proposed. Its originality is to be supported, on one hand, by experimental results obtained via wear machines of relatively short operational times, and, on the other hand, by the information obtained from the operating feedback over real wear kinetics of the reactors components. The proposed model is illustrated by an example which correspond to a specific real situation. The determination of the coefficients permitting to cover all assembly of configurations and the validation of the model in these configurations have been the object of the most recent work

  17. Microstructure and Wear Behavior of CoCrFeMnNbNi High-Entropy Alloy Coating by TIG Cladding

    Directory of Open Access Journals (Sweden)

    Wen-yi Huo

    2015-01-01

    Full Text Available Alloy cladding coatings are widely prepared on the surface of tools and machines. High-entropy alloys are potential replacements of nickel-, iron-, and cobalt-base alloys in machining due to their excellent strength and toughness. In this work, CoCrFeMnNbNi HEA coating was produced on AISI 304 steel by tungsten inert gas cladding. The microstructure and wear behavior of the cladding coating were studied by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometer, microhardness tester, pin-on-ring wear tester, and 3D confocal laser scanning microscope. The microstructure showed up as a nanoscale lamellar structure matrix which is a face-centered-cubic solid solution and niobium-rich Laves phase. The microhardness of the cladding coating is greater than the structure. The cladding coating has excellent wear resistance under the condition of dry sliding wear, and the microploughing in the worn cladding coating is shallower and finer than the worn structure, which is related to composition changes caused by forming the nanoscale lamellar structure of Laves phase.

  18. Effect of mechanical vibrations on the wear behavior of AZ91 Mg alloy

    Science.gov (United States)

    Chaturvedi, V.; Pandel, U.; Sharma, A.

    2018-02-01

    AZ91 Mg alloy is the most promising alloy used for structural applications. The vibration induced methods are effective and economic viable in term of mechanical properties. Sliding wear tests were performed on AZ91 Mg alloy using a pin-on- disc configuration. Wear rates were measured at 5 N and 10N at a sliding velocity of 1m/s for varied frequency within the range of 5- 25Hz and a constant amplitude of 2mm. Microstructures of worn surfaces and wear debris were characterized by field emission scanning electron microscopy (FESEM). It is observed that wear resistance of vibrated AZ91 alloy at 15Hz frequency ad 2mm amplitude was superior than cast AZ91 Mg alloy. Finer grain size and equiaxed grain shape both are important parameters for better wear resistance in vibrated AZ91 Mg alloys. FESEM analysis revealed that wear is considerably affected due to frictional heat generated by the relative motion between AZ91 Mg alloy and EN31 steel surface. No single mechanism was responsible for material loss.

  19. A kinetic model for impact/sliding wear of pressurized water reactor internal components. Application to rod cluster control assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Zbinden, M; Durbec, V

    1996-12-01

    A new concept of industrial wear model adapted to components of nuclear plants is proposed. Its originality is to be supported, on one hand, by experimental results obtained via wear machines of relatively short operational times, and, on the other hand, by the information obtained from the operating feedback over real wear kinetics of the reactors components. The proposed model is illustrated by an example which corresponds to a specific real situation. The determination of the coefficients permitting to cover all assembly of configurations and the validation of the model in these configurations have been the object of the most recent work. (author). 34 refs.

  20. A kinetic model for impact/sliding wear of pressurized water reactor internal components. Application to rod cluster control assemblies

    International Nuclear Information System (INIS)

    Zbinden, M.; Durbec, V.

    1996-12-01

    A new concept of industrial wear model adapted to components of nuclear plants is proposed. Its originality is to be supported, on one hand, by experimental results obtained via wear machines of relatively short operational times, and, on the other hand, by the information obtained from the operating feedback over real wear kinetics of the reactors components. The proposed model is illustrated by an example which corresponds to a specific real situation. The determination of the coefficients permitting to cover all assembly of configurations and the validation of the model in these configurations have been the object of the most recent work. (author)

  1. Influence of applied load on wear behavior of C/C-Cu composites under electric current

    Directory of Open Access Journals (Sweden)

    Jian Yin

    2017-04-01

    Full Text Available Using carbon fiber needled fabrics with Cu-mesh and graphite powder as the preform, Cu mesh modified carbon/carbon(C/C-Cu composites were prepared by chemical vapor deposition (CVD with C3H6 and impregnation-carbonization (I/C with furan resin. C/C composites, as a comparison, were also prepared. Their microstructures and wear morphologies were observed by optical microscopy (OM and scanning electron microscope (SEM, respectively. Wear behavior of C/C and C/C-Cu composites under different applied loads were investigated on a pin-on-disc wear tester. The results show that Cu meshes are well dispersed and pyrolytic carbon is in rough laminar structure. Both C/C and C/C-Cu composites had good wear properties. The current-carrying capacity of C/C-Cu composites increases and the arc discharge is hindered as the applied load increases from 40 N to 80 N. Both C/C and C/C-Cu composites had good wear properties. The mass wear rate of C/C-Cu composites under 80 N was only 4.2% of that under 60 N. In addition, C/C-Cu composites represent different wear behaviors because wear mechanisms of arc erosion, abrasive wear, adhesive wear, and oxidative wear are changing under different applied loads.

  2. Slide 1

    Indian Academy of Sciences (India)

    Table of contents. Slide 1 · Slide 2 · Slide 3 · Slide 4 · Slide 5 · Slide 6 · Slide 7 · Slide 8 · Slide 9 · Slide 10 · Slide 11 · Slide 12 · Slide 13 · Slide 14 · Slide 15 · Slide 16 · Slide 17.

  3. Microstructural evolution and wear behaviors of laser cladding Ti_2Ni/α(Ti) dual-phase coating reinforced by TiB and TiC

    International Nuclear Information System (INIS)

    Song, R.; Li, J.; Shao, J.Z.; Bai, L.L.; Chen, J.L.; Qu, C.C.

    2015-01-01

    Graphical abstract: - Highlights: • A TiC+TiB reinforced intermetallic matrix coating was fabricated by laser cladding. • The microstructural evolution of the reinforcements was analyzed. • A formula was established in term of wear loss, sliding time and applied load. • Wear behaviors were investigated by in situ continuing tests in different time intervals. • The transformation of wear mechanism at different applied loads was revealed. - Abstract: The Ti_2Ni/α(Ti) dual-phase coating reinforced by TiB and TiC was fabricated on the Ti6Al4V substrate by laser cladding. Phase constituents were confirmed by a theoretical prediction combined with X-ray diffraction (XRD) analyses. From the surface to the bottom of the coating, a regular evolution of the reinforcements’ microstructure, namely TiC_p+(TiB+TiC)_e, (TiB+TiC)_e and TiB_p+(TiB+TiC)_e (p and e were the abbreviations of primary and eutectic, respectively), was investigated by scanning electron microscopy (SEM). The coating possessed the higher microhardness than that of the substrate. An in situ dynamic method (in situ continuing tests at different time intervals) was designed to reveal wear behaviors at different wear stages. A quantitative calculation formula was established by a mathematic model to predict wear losses under different sliding time and applied loads in a definite precision. The wear mechanism was transformed from brittle debonding (at 10 N) to the joint action of brittle debonding and micro-cutting (at 20 N and 30 N) due to the microstructural evolution across the depth from the surface of the coating.

  4. Slide 1

    Indian Academy of Sciences (India)

    Table of contents. Slide 1 · Slide 2 · Membrane Phospholipids · Slide 4 · NAE and NAPE · Biological and Pharmacological properties · Slide 7 · Slide 8 · Slide 9 · Slide 10 · Slide 11 · Slide 12 · Slide 13 · Slide 14 · Slide 15 · Slide 16 · Slide 17 · Slide 18 · Slide 19 · Slide 20 · Slide 21 · Slide 22 · Slide 23 · Slide 24 · Slide 25.

  5. Study on the Correlation Between Dynamical Behavior and Friction/Wear Mechanism Under the Effect of Grooves

    Science.gov (United States)

    Zhu, Z. Y.; Mo, J. L.; Wang, D. W.; Zhao, J.; Zhu, M. H.; Zhou, Z. R.

    2018-04-01

    In this work, the interfacial friction and wear and vibration characteristics are studied by sliding a chromium bearing steel ball (AISI 52100) over both multi-grooved and single-grooved forged steel disks (20CrMnMo) at low and high rotating speeds in order to reveal the effect mechanism of groove-textured surface on tribological behaviors. The results show that the grooves modify the contact state of the ball and the disk at the contact interface. This consequently causes variations in the normal displacement, normal force, and friction force signals. The changes in these three signals become more pronounced with increasing groove width at a low speed. The collision behavior between the ball and the groove increase the amplitude of vibration acceleration at a high speed. The test results suggest that grooves with appropriate widths could trap wear debris on the ball surface while avoiding a strong collision between the disk and the ball, resulting in an improvement in the wear states.

  6. WearSense: Detecting Autism Stereotypic Behaviors through Smartwatches

    Directory of Open Access Journals (Sweden)

    Amir Mohammad Amiri

    2017-02-01

    Full Text Available Autism is a complex developmental disorder that affects approximately 1 in 68 children (according to the recent survey conducted by the Centers for Disease Control and Prevention—CDC in the U.S., and has become the fastest growing category of special education. Each student with autism comes with her or his own unique needs and an array of behaviors and habits that can be severe and which interfere with everyday tasks. Autism is associated with intellectual disability, impairments in social skills, and physical health issues such as sleep and abdominal disturbances. We have designed an Internet-of-Things (IoT framework named WearSense that leverages the sensing capabilities of modern smartwatches to detect stereotypic behaviors in children with autism. In this work, we present a study that used the inbuilt accelerometer of a smartwatch to detect three behaviors, including hand flapping, painting, and sibbing that are commonly observed in children with autism. In this feasibility study, we recruited 14 subjects to record the accelerometer data from the smartwatch worn on the wrist. The processing part extracts 34 different features in each dimension of the three-axis accelerometer, resulting in 102 features. Using and comparing various classification techniques revealed that an ensemble of 40 decision trees has the best accuracy of around 94.6%. This accuracy shows the quality of the data collected from the smartwatch and feature extraction methods used in this study. The recognition of these behaviors by using a smartwatch would be helpful in monitoring individuals with autistic behaviors, since the smartwatch can send the data to the cloud for comprehensive analysis and also to help parents, caregivers, and clinicians make informed decisions.

  7. Wear behavior of human enamel against lithium disilicate glass ceramic and type III gold.

    Science.gov (United States)

    Lee, Ahreum; Swain, Michael; He, Lihong; Lyons, Karl

    2014-12-01

    The wear behavior of human enamel that opposes different prosthetic materials is still not clear. The purpose of this in vitro study was to investigate and compare the friction and wear behavior of human tooth enamel that opposes 2 indirect restorative materials: lithium disilicate glass ceramic and Type III gold. Friction-wear tests on human enamel (n=5) that opposes lithium disilicate glass ceramic (n=5) and Type III gold (n=5) were conducted in a ball-on-flat configuration with a reciprocating wear testing apparatus. The wear pairs were subjected to a normal load of 9.8 N, a reciprocating amplitude of approximately 200 μm, and a reciprocating frequency of approximately 1.6 Hz for up to 1100 cycles per test under distilled water lubrication. The frictional force of each cycle was recorded, and the corresponding friction coefficient for different wear pairs was calculated. After wear testing, the wear scars on the enamel specimens were examined under a scanning electron microscope. Type III gold had a significantly lower steady-state friction coefficient (P=.009) and caused less wear damage on enamel than lithium disilicate glass ceramic. Enamel that opposed lithium disilicate glass ceramic exhibited cracks, plow furrows, and surface loss, which indicated abrasive wear as the prominent wear mechanism. In comparison, the enamel wear scar that opposed Type III gold had small patches of gold smear adhered to the surface, which indicated a predominantly adhesive wear mechanism. A lower friction coefficient and better wear resistance were observed when human enamel was opposed by Type III gold than by lithium disilicate glass ceramic in vitro. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  8. Sliding behavior of oil droplets on nanosphere stacking layers with different surface textures

    International Nuclear Information System (INIS)

    Hsieh, Chien-Te; Wu, Fang-Lin; Chen, Wei-Yu

    2010-01-01

    Two facile coating techniques, gravitational sediment and spin coating, were applied for the creation of silica sphere stacking layers with different textures onto glass substrates that display various sliding abilities toward liquid drops with different surface tensions, ranged from 25.6 to 72.3 mN/m. The resulting silica surface exhibits oil repellency, long-period durability > 30 days, and oil sliding capability. The two-tier texture offers a better roll-off ability toward liquid drops with a wide range of γ L , ranged from 30.2 to 72.3 mN/m, i.e., when the sliding angle (SA) ad ) appears to describe the sliding behavior within the W ad region: 2.20-3.03 mN/m. The smaller W ad , the easier drop sliding (i.e., the smaller SA value) takes place on the surfaces. The W ad value ∼3.03 mN/m shows a critical kinetic barrier for drop sliding on the silica surfaces from stationary to movement states. This work proposes a mathematical model to simulate the sliding behavior of oil drops on a nanosphere stacking layer, confirming the anti-oil contamination capability.

  9. Thermal Treatment, Sliding Wear and Saline Corrosion of Al In Situ Reinforced with Mg2Si and Ex Situ Reinforced with TiC Particles

    Science.gov (United States)

    Lekatou, A. G.; Poulia, A.; Mavros, H.; Karantzalis, A. E.

    2018-02-01

    The main objective of this work is to produce a composite consisting of (a) a cast heat-treatable Al-Mg-Si alloy with high contents of Mg for corrosion resistance and Si to offset the Mg-due poor castability (in situ hypoeutectic Mg2Si/Al composite) and (b) TiC particles at high enough volume fractions (≤ 15%), in order to achieve a satisfactory combination of wear and corrosion performance. TiCp/Al-7Mg-5Si (wt.%) composites were produced by flux-assisted casting followed by solution and aging heat treatment. Solution treatment led to a relatively uniform dispersion and shape rounding of Mg2Si precipitates and Si particles. TiC particle addition resulted in refinement of primary Al, modification of the Mg2Si Chinese script morphology and refinement/spheroidization of primary Mg2Si. Heat treatment combined with TiC addition notably improved the sliding wear resistance of Al-7Mg-5Si. A wear mechanism has been proposed. The TiC/Al interfaces remained intact of corrosion during potentiodynamic polarization of the heat-treated materials in 3.5 wt.% NaCl. Different main forms of localized corrosion in 3.5 wt.% NaCl were identified for each TiC content (0, 5, 15 vol.%), depending on specific degradation favoring microstructural features (topology/size/interface wetting) at each composition.

  10. Microstructure and Sliding Wear Behaviour of In-Situ TiC-Reinforced Composite Surface Layers Fabricated on Ductile Cast Iron by Laser Alloying.

    Science.gov (United States)

    Janicki, Damian

    2018-01-05

    TiC-reinforced composite surface layers (TRLs) on a ductile cast iron EN-GJS-700-2 grade (DCI) substrate were synthesized using a diode laser surface alloying with a direct injection of titanium powder into the molten pool. The experimental results were compared with thermodynamic calculations. The TRLs having a uniform distribution of the TiC particles and their fraction up to 15.4 vol % were achieved. With increasing titanium concentration in the molten pool, fractions of TiC and retained austenite increase and the shape of TiC particles changes from cubic to dendritic form. At the same time, the cementite fraction decreases, lowering the overall hardness of the TRL. A good agreement between experimental and calculated results was achieved. Comparative dry sliding wear tests between the as-received DCI, the TRLs and also laser surface melted layers (SMLs) have been performed following the ASTM G 99 standard test method under contact pressures of 2.12 and 4.25 MPa. For both the as-received DCI and the SMLs, the wear rates increased with increasing contact pressure. The TRLs exhibited a significantly higher wear resistance than the others, which was found to be load independent.

  11. Comparison study on resistance to wear and abrasion of high-temperature sliding strike of laser and plasma spray layer on the stainless steel surface

    International Nuclear Information System (INIS)

    Shi Shihong; Zheng Qiguang; Fu Geyan; Wang Xinlin

    2004-01-01

    In this paper, the effect of coatings, which are formed with laser cladding and plasma spray welding on 1Cr18Ni9Ti base metal of nuclear valve seats, on wear resistance is studied. A 5-kW transverse-flowing CO 2 laser is used for cladding Co base alloy powder pre-placed on the substrate. Comparing with the plasma spray coatings, the laser-cladding layer have lower rate of spoiled products and higher rate of finished products. Their microstructure is extremely fine. They have close texture and small-size grain. Their dilution diluted by the compositions of their base metal and hot-effect on base metal are less. The hardness, toughness, and strength of the laser-cladding layers are higher. The grain size is 11-12th grade in the laser-cladding layer and 9-10th in the plasma spray layer. The width of combination zone between laser-cladding layer and substrate is 10-45 μm but that between plasma spray layer and substrate is 120-160 μm. The wear test shows that the laser layers have higher property of anti-friction, anti-scour, and high-temperature sliding strike. The wear resistance of laser-cladding layer is about one time higher than that of plasma spray welding layer

  12. Sliding wear and corrosion behaviour of alloyed austempered ductile iron subjected to novel two step austempering treatment

    Science.gov (United States)

    Sethuram, D.; Srisailam, Shravani; Rao Ponangi, Babu

    2018-04-01

    Austempered Ductile Iron(ADI) is an exciting alloy of iron which offers the design engineers the best combination high strength-to-weight ratio, low cost design flexibility, good toughness, wear resistance along with fatigue strength. The two step austempering procedure helps in simultaneously improving the tensile strength as-well as the ductility to more than that of the conventional austempering process. Extensive literature survey reveals that it’s mechanical and wear behaviour are dependent on heat treatment and alloy additions. Current work focuses on characterizing the two-step ADI samples (TSADI) developed by novel heat treatment process for resistance to corrosion and wear. The samples of Ductile Iron were austempered by the two-Step Austempering process at temperatures 300°C to 450°C in the steps of 50°C.Temperaturesare gradually increased at the rate of 14°C/Hour. In acidic medium (H2SO4), the austempered samples showed better corrosive resistance compared to conventional ductile iron. It has been observed from the wear studies that TSADI sample at 350°C is showing better wear resistance compared to ductile iron. The results are discussed in terms of fractographs, process variables and microstructural features of TSADI samples.

  13. Friction and Wear Behavior of Several Hard Materials

    NARCIS (Netherlands)

    Quercia Bianchi, G.; Grigorescu, I.C.; Di Rauso, C.; Contreras, H.; Gutierrez, D.

    2001-01-01

    Sliding friction, abrasion and erosion tests were performed on several materials: cemented carbides, partially stabilized zirconia (Mg–PSZ), electroless Ni–P coatings and SAE 4140 steel as reference material. Sliding friction test was carried out in a pin-on-disk system. A micro-abrasion test was

  14. Fundamental studies on dynamic wear behavior of SBR rubber compounds modified by SBR rubber powder

    OpenAIRE

    Euchler, Eric; Heinrich, Gert; Michael, Hannes; Gehde, Michael; Stocek, Radek; Kratina, Ondrej; Kipscholl, Reinhold; Bunzel, Jörg-Michael; Saal, Wolfgang

    2016-01-01

    The aim of this study is focused on the experimental investigation of dynamic wear behavior of carbon black filled rubber compounds comprising pristine styrene butadiene rubber (SBR) together with incorporated SBR ground rubber (rubber powder). We also analyzed and described quantitatively the service conditions of some dynamically loaded rubber products, which are liable to wear (e.g. conveyor belts, tires). Beside the well-known standard test method to characterize wear resistance at steady...

  15. Tribology of Si/SiO2 in humid air: transition from severe chemical wear to wearless behavior at nanoscale.

    Science.gov (United States)

    Chen, Lei; He, Hongtu; Wang, Xiaodong; Kim, Seong H; Qian, Linmao

    2015-01-13

    Wear at sliding interfaces of silicon is a main cause for material loss in nanomanufacturing and device failure in microelectromechanical system (MEMS) applications. However, a comprehensive understanding of the nanoscale wear mechanisms of silicon in ambient conditions is still lacking. Here, we report the chemical wear of single crystalline silicon, a material used for micro/nanoscale devices, in humid air under the contact pressure lower than the material hardness. A transmission electron microscopy (TEM) analysis of the wear track confirmed that the wear of silicon in humid conditions originates from surface reactions without significant subsurface damages such as plastic deformation or fracture. When rubbed with a SiO2 ball, the single crystalline silicon surface exhibited transitions from severe wear in intermediate humidity to nearly wearless states at two opposite extremes: (a) low humidity and high sliding speed conditions and (b) high humidity and low speed conditions. These transitions suggested that at the sliding interfaces of Si/SiO2 at least two different tribochemical reactions play important roles. One would be the formation of a strong "hydrogen bonding bridge" between hydroxyl groups of two sliding interfaces and the other the removal of hydroxyl groups from the SiO2 surface. The experimental data indicated that the dominance of each reaction varies with the ambient humidity and sliding speed.

  16. Impact Fretting Wear Behavior of Alloy 690 Tubes in Dry and Deionized Water Conditions

    Institute of Scientific and Technical Information of China (English)

    Zhen-Bing Cai; Jin-Fang Peng; Hao Qian; Li-Chen Tang; Min-Hao Zhu

    2017-01-01

    The impact fretting wear has largely occurred at nuclear power device induced by the flow-induced vibration,and it will take potential hazards to the service of the equipment.However,the present study focuses on the tangential fretting wear of alloy 690 tubes.Research on impact fretting wear of alloy 690 tubes is limited and the related research is imminent.Therefore,impact fretting wear behavior of alloy 690 tubes against 304 stainless steels is investigated.Deionized water is used to simulate the flow environment of the equipment,and the dry environment is used for comparison.Varied analytical techniques are employed to characterize the wear and tribochemical behavior during impact fretting wear.Characterization results indicate that cracks occur at high impact load in both water and dry equipment;however,the water as a medium can significantly delay the cracking time.The crack propagation behavior shows a jagged shape in the water,but crack extended disorderly in dry equipment because the water changed the stress distribution and retarded the friction heat during the wear process.The SEM and XPS analysis shows that the main failure mechanisms of the tube under impact fretting are fatigue wear and friction oxidation.The effect of medium(water) on fretting wear is revealed,which plays a potential and promising role in the service of nuclear power device and other flow equipments.

  17. Effect of Microstructure on the Wear Behavior of Heat Treated SS-304 Stainless Steel

    OpenAIRE

    S. Kumar

    2016-01-01

    Sliding wear characteristics of some heat treated SS-304 stainless steel against EN-8 steel in dry condition have been studied in the present experimental work. Samples of SS-304 stainless steel have been heated in a muffle furnace in desired temperature and allowed to dwell for two hours. The heated specimen are then cooled in different media namely inside the furnace, open air, cutting grade oil (grade 44) and water at room temperature to obtain different grades of heat treatment. Microstr...

  18. Slide 1

    Indian Academy of Sciences (India)

    Table of contents. Slide 1 · Slide 2 · Slide 3 · Slide 4 · Slide 5 · Slide 6 · Slide 7 · Immunology of VL · Slide 9 · Slide 10 · Slide 11 · Slide 12 · Slide 13 · Slide 14 · Strategies To Design Drugs · Slide 16 · Slide 17 · Slide 18 · Slide 19 · Slide 20 · Slide 21 · Slide 22 · Slide 23 · Slide 24 · Slide 25 · Slide 26 · Slide 27 · Slide 28.

  19. A Study on the Sliding/Impact Wear of a Nuclear Fuel Rod in Room Temperature Air: (I) Development of a Test Rig and Characteristic Analysis

    International Nuclear Information System (INIS)

    Lee, Young Ho; Lee, Kang Hee; Kim, Hyung Kyu

    2007-01-01

    A new type of a fretting wear tester has been designed and developed in order to simulate the actual vibration behavior of a nuclear fuel rod for springs/dimples in room temperature. When considering the actual contact condition between fuel rod and spring/dimple, if fretting wear progress due to the Flow-Induced Vibration (FIV) under a specific normal load exerted on the fuel rod by the elastic deformation of the spring, the contacting force between the fuel rod and dimple that were located in the opposite side should be decreased. Consequently, the evaluation of developed spacer grids against fretting wear damage should be performed with the results of a cell unit experiments because the contacting force is one of the most important variables that influence to the fretting wear mechanism. Therefore, it is necessary to develop a new type of fretting test rig in order to simulate the actual contact condition. In this paper, the development procedure of a new fretting wear tester and its performance were discussed in detail

  20. Slide 1

    Indian Academy of Sciences (India)

    Slide 5 · Slide 6 · Second Question How Did this Shift in ToT Come About? Slide 8 · Second Question How Did this Shift in ToT Come About? Slide 10 · Slide 11 · Slide 12 · Slide 13 · Slide 14 · Slide 15 · Slide 17 · Slide 20 · Slide 21 · Slide 22 · Slide 23 · Slide 24 · Slide 25 · Slide 26 · Slide 27 · Slide 30 · India's Globalization.

  1. Wear behavior of tetragonal zirconia polycrystal versus titanium and titanium alloy

    International Nuclear Information System (INIS)

    Kanbara, Tsunemichi; Yajima, Yasutomo; Yoshinari, Masao

    2011-01-01

    The aim of this study was to clarify the influence of tetragonal zirconia polycrystal (TZP) on the two-body wear behavior of titanium (Ti). Two-body wear tests were performed using TZP, two grades of cp-Ti or Ti alloy in distilled water, and the cross-sectional area of worn surfaces was measured to evaluate the wear behavior. In addition, the surface hardness and coefficient of friction were determined and an electron probe microanalysis performed to investigate the underlying mechanism of wear. The hardness of TZP was much greater than that of Ti. The coefficient of friction between Ti and Ti showed a higher value than the Ti/TZP combination. Ti was more susceptible to wear by both TZP and Ti than TZP, indicating that the mechanism of wear between TZP and Ti was abrasive wear, whereas that between Ti and Ti was adhesive wear. No remarkable difference in the amount of wear in Ti was observed between TZP and Ti as the opposite material, despite the hardness value of Ti being much smaller than that of TZP. (communication)

  2. Wear Behavior of Aluminium Metal Matrix Composite Prepared from Industrial Waste

    Directory of Open Access Journals (Sweden)

    L. Francis Xavier

    2016-01-01

    Full Text Available With an increase in the population and industrialization, a lot of valuable natural resources are depleted to prepare and manufacture products. However industrialization on the other hand has waste disposal issues, causing dust and environmental pollution. In this work, Aluminium Metal Matrix Composite is prepared by reinforcing 10 wt% and 20 wt% of wet grinder stone dust particles an industrial waste obtained during processing of quarry rocks which are available in nature. In the composite materials design wear is a very important criterion requiring consideration which ensures the materials reliability in applications where they come in contact with the environment and other surfaces. Dry sliding wear test was carried out using pin-on-disc apparatus on the prepared composites. The results reveal that increasing the reinforcement content from 10 wt% to 20 wt% increases the resistance to wear rate.

  3. Wear behavior of niobium carbide coated AISI 52100 steel

    International Nuclear Information System (INIS)

    Fernandes, Frederico Augusto Pires; Casteletti, Luiz Carlos; Oliveira, Carlos Kleber Nascimento de; Lombardi Neto, Amadeu; Totten, George Edward

    2010-01-01

    Bearing steels must have high hardness, good wear resistance and dimensional stability. The aim of this work was to study the effect of NbC coating, produced using the thermo-reactive deposition (TRD) process, on the wear resistance of the AISI 52100 steel. Untreated AISI 52100 samples were ground up to 600 mesh emery paper. The bath was composed of 5wt.% ferroniobium (65 wt.% Nb), 3wt.% aluminum and (Na2B4O7) to 100%. Samples were treated at 1000 deg C for 4h and quenched in oil directly from the bath. The resulting layer was characterized by X-ray diffraction, scanning electron microscopy and a micro-abrasive wear testing. The thermo-reactive deposition process in molten borax produced a hard and homogeneous layer composed by NbC, which was confirmed by X-ray diffraction. The NbC coating produced a great increase in the wear resistance of the AISI 52100 steel, decreasing the wear rate by an order of magnitude in relation to the substrate. For coated and uncoated samples the worn volume and wear rate increases with the load. (author)

  4. Wear behaviors of pure aluminum and extruded aluminum alloy (AA2024-T4) under variable vertical loads and linear speeds

    Science.gov (United States)

    Jung, Jeki; Oak, Jeong-Jung; Kim, Yong-Hwan; Cho, Yi Je; Park, Yong Ho

    2017-11-01

    The aim of this study was to investigate the transition of wear behavior for pure aluminum and extruded aluminum alloy 2024-T4 (AA2024-T4). The wear test was carried using a ball-on-disc wear testing machine at various vertical loads and linear speeds. The transition of wear behaviors was analyzed based on the microstructure, wear tracks, wear cross-section, and wear debris. The critical wear rates for each material are occurred at lower linear speed for each vertical load. The transition of wear behavior was observed in which abrasion wears with the generation of an oxide layer, fracture of oxide layer, adhesion wear, severe adhesion wear, and the generation of seizure occurred in sequence. In case of the pure aluminum, the change of wear debris occurred in the order of blocky, flake, and needle-like debris. Cutting chip, flake-like, and coarse flake-like debris was occurred in sequence for the extruded AA2024-T4. The transition in the wear behavior of extruded AA2024-T4 occurred slower than in pure aluminum.

  5. A Study on Abrasive Wear Behavior of Spacer Grid Materials for Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. M.; Kim, J. H. [Chungnam National University, Daejeon (Korea, Republic of); Park, J. K.; Jeon, K. L. [Korea Nuclear Fuel, Daejeon (Korea, Republic of)

    2010-10-15

    Spacer grid is one of the key components of a light water reactor (LWR) fuel assembly. The most important function of it is to hold the fuel rods to maintain the distance between the fuel rods inside a fuel assembly. At the reactor core in operating power plants, a fretting damage has been frequently reported between a nuclear fuel rod and its supporting spring/dimple of the fuel assemblies. This is due to a flow induced vibration (FIV), Which results from the primary coolant that rapidly passes around the fuel rod to remove the excess heat generated by the nuclear reaction. Fretting damage is generally caused by fretting wear, which includes various wear mechanisms such as an oxidative, adhesive, abrasive wear, etc., or fretting fatigue, which includes a surface or bulk fatigue. The purpose of the present work are to investigate the variation of the materials with increasing number of cycles and sliding velocity under abrasive wear test and to examine the wear mechanism at each test condition

  6. Comparative study of the friction and wear behavior of plasma sprayed conventional and nanostructured WC-12%Co coatings on stainless steel

    International Nuclear Information System (INIS)

    Zhao Xiaoqin; Zhou Huidi; Chen Jianmin

    2006-01-01

    Conventional and nanostructured WC-12%Co coatings were deposited on 1Cr18Ni9Ti stainless steel substrate using air plasma spraying. The hardness of the coatings was measured, while their friction and wear behavior sliding against Si 3 N 4 at room temperature and elevated temperatures up to 400 deg. C was comparatively studied. The microstructures and worn surface morphologies of the coatings were comparatively analyzed as well by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDXA). It was found that the as-sprayed WC-12%Co coatings were composed of WC as the major phase and W 2 C, WC 1-x , and W 3 Co 3 C as the minor phases. The plasma sprayed nanostructured WC-12%Co coating had much higher hardness and refined microstructures than the conventional WC-12%Co coating. This largely accounted for the better wear resistance of the nanostructured WC-12%Co coating than the conventional coating. Besides, the two types of WC-12%Co coatings showed minor differences in friction coefficients, though the nanostructured WC-12%Co coating roughly had slightly smaller friction coefficient than the conventional coating under the same sliding condition. Moreover, both the conventional and nanostructured WC-12%Co coatings recorded gradually increased wear rate with increasing temperature, and the nanostructured coating was less sensitive to the temperature rise in terms of the wear resistance. The worn surfaces of the conventional WC-12%Co coating at different sliding conditions showed more severe adhesion, microfracture, and peeling as compared to the nanostructured WC-12%Co coating, which well conformed to the corresponding wear resistance of the two types of coatings. The nanostructured WC-12%Co coating with a wear rate as small as 1.01 x 10 -7 mm 3 /Nm at 400 deg. C could be promising candidate coating for the surface-modification of some sliding components subject to harsh working conditions involving elevated

  7. Low-Velocity Impact Wear Behavior of Ball-to-Flat Contact Under Constant Kinetic Energy

    Science.gov (United States)

    Wang, Zhang; Cai, Zhen-bing; Chen, Zhi-qiang; Sun, Yang; Zhu, Min-hao

    2017-11-01

    The impact tests were conducted on metallic materials with different bulk hardness and Young's moduli. Analysis of the dynamics response during the tribological process showed that the tested materials had similar energy absorption, where the peak contact force increased as the tests continued. Moreover, wear volume decreased with the increase in Young's modulus of metals, except for Cr with a relatively low hardness. Wear rate was gradually reduced to a steady stage with increasing cycles, which was attributed to the decrease in contact stress and work-hardening effect. The main wear mechanism of impact was characterized by delamination, and the specific surface degradation mechanisms were depending on the mechanical properties of materials. The absorbed energy was used to the propagation of micro-cracks in the subsurface instead of plastic deformation, when resistance of friction wear and plastic behavior was improved. Hence, both the hardness and Young's modulus played important roles in the impact wear of metallic materials.

  8. Influence of Cryogenic Treatments on the Wear Behavior of AISI 420 Martensitic Stainless Steel

    Science.gov (United States)

    Prieto, G.; Tuckart, W. R.

    2017-11-01

    The objective of the present work is to characterize the wear behavior of a cryogenically treated low-carbon AISI 420 martensitic stainless steel, by means of ball-on-disk tribological tests. Wear tests were performed under a range of applied normal loads and in two different environments, namely a petrolatum bath and an argon atmosphere. Wear tracks were analyzed by both optical and scanning electron microscopy and Raman spectroscopy to evaluate wear volume, track geometry, surface features and the tribolayers generated after testing. This paper is an extension of the work originally reported in the VIII Iberian Conference of Tribology (Prieto and Tuckart, in: Ballest Jiménez, Rodríguez Espinosa, Serrano Saurín, Pardilla Arias, Olivares Bermúdez (eds) VIII Iberian conference of tribology, Cartagena, 2015). In this study, it has been experimentally demonstrated that cryogenically treated specimens showed a wear resistance improvement ranging from 35 to 90% compared to conventionally treated ones.

  9. Tribological Investigation of SiC/Al Composite under Dry Sliding Friction

    Directory of Open Access Journals (Sweden)

    DAI Liquan

    2016-12-01

    Full Text Available The effect of sliding distances on aluminum matrix composite reinforced by silicon carbide particle with volume fraction of 9% was investigated. Friction behavior and wear resistance of the composite with distances of 5000 r, 10000 r and 20000 r were studied under dry sliding conditions of the same speed and load(200 r/min, 45 N. The results show that the friction coefficient in long-range sliding process displays three stages:wearing zone, stable zone and accelerating zone. The matrix surface produces severe adhesion because of the rising temperature and then leads plastic areas, in which both friction coefficient and wear rate are increased.

  10. Nano-crystallization of steel wire and its wear behavior

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Y.H. [School of Electromechanical Engineering, Xian University of Architecture and Technology, Xian 716000 (China) and School of Materials Science and Engineering, Northwestern Polytecnical University, Xian 710072 (China)], E-mail: xuyunhua@vip.163.com; Peng, J.H. [School of Electromechanical Engineering, Xian University of Architecture and Technology, Xian 716000 (China); Fang, L. [State Key Laboratory for Mechanical Behavior of Materials, Xian Jiaotong University, Xian 710049 (China)

    2008-06-15

    As carbon steel wire is widely used in civil engineering and industry, it is quite important to increase its strength. In the present paper, a severe cold drawing approach is applied to increase strength and is shown to produce nano grains. With increasing true strain, the tensile strength increases continuously and the cementite flake thickness decreases correspondingly. It is observed by transmission electron microscopy that a significant amount of cementite flakes have been fragmented and dissolved at true strains. Finally, the grains are transformed to nano-sized crystals. Additionally, the cold drawn nano-sized steel wire has been knitted and filled with polyurethane to produce a composite material. Three-body abrasive wear tests show that the wear resistance of the test material is even better than that of high-Cr white cast irons.

  11. Nano-crystallization of steel wire and its wear behavior

    International Nuclear Information System (INIS)

    Xu, Y.H.; Peng, J.H.; Fang, L.

    2008-01-01

    As carbon steel wire is widely used in civil engineering and industry, it is quite important to increase its strength. In the present paper, a severe cold drawing approach is applied to increase strength and is shown to produce nano grains. With increasing true strain, the tensile strength increases continuously and the cementite flake thickness decreases correspondingly. It is observed by transmission electron microscopy that a significant amount of cementite flakes have been fragmented and dissolved at true strains. Finally, the grains are transformed to nano-sized crystals. Additionally, the cold drawn nano-sized steel wire has been knitted and filled with polyurethane to produce a composite material. Three-body abrasive wear tests show that the wear resistance of the test material is even better than that of high-Cr white cast irons

  12. The influence of social networking technologies on female religious veil-wearing behavior in Iran.

    Science.gov (United States)

    Young, Sean D; Shakiba, Abbas; Kwok, Justin; Montazeri, Mohammad Sadegh

    2014-05-01

    Abstract Social networking technologies can influence attitudes, behaviors, and social norms. Research on this topic has been conducted primarily among early adopters of technology and within the United States. However, it is important to evaluate how social media might affect people's behaviors in international settings, especially among countries with longstanding, government recommended, cultural and religious traditions and behaviors, such as Iran. This study seeks to assess whether Iranian women who have been using social networking technologies for a longer time (compared to those who have recently joined) would be less likely to cover themselves with a veil and be more comfortable publicly displaying pictures of this behavior on Facebook. Iranian females (N=253) were selected through snowball sampling from nongovernmental organizations in November 2011 and asked to complete a survey assessing their use of Facebook, concerns about not wearing a veil in Facebook pictures, and their actual likelihood of wearing a veil. Items were combined to measure lack of interest in wearing a veil. Length of time as a Facebook user was significantly associated with not wearing a veil (b=0.16, peducation, and frequency of using Facebook. Results also revealed a significant relationship such that older people were more likely to adhere to the religious behavior of wearing a veil (b=-0.45, ptechnologies can affect attitudes and behaviors internationally. We discuss methods of using social media for self-presentation and expression, as well as the difficulties (and importance) of studying use of technologies, such as social media, internationally.

  13. Slide 1

    Indian Academy of Sciences (India)

    Table of contents. Slide 1 · Matsyagandhya A case of genetic disorder · Slide 3 · Slide 4 · Slide 5 · Slide 6 · Slide 7 · Active Site with Molybdopterin Ligation · Disadvantage of a Chemist to Model the Cofactor · Slide 10 · Slide 11 · Slide 12 · Active Site Investigation · Slide 14 · Slide 15 · Slide 16 · Slide 17 · Slide 18 · Slide 19.

  14. Wear behavior of tempered and borided tool steels under various conditions

    International Nuclear Information System (INIS)

    Al-Haidary, T. J.; Faleh, M. N.

    2000-01-01

    . Tool steel 61CrV5, 50 NiCr13 and X1000Cr MoV51 were used in the first stage of this investigation. They have been treated as follows: boriding, boriding and tempering and hardening and tempering. The wear tests were conducted under fixed conditions (150 N/mm 2 , 0.48m/sec) with and without lubricant. The wear rate and coefficient of friction of 61Cr Si V5 steel have been studied in the second stage hoping to find the influence of working conditions on these parameters and then to compare these results with the case of hardening and tempering which is the usual case in the actual working field. The study gives a good indication about the improvement achieved in boriding and tempering cases (∼ 30%) as compared with hardening tempering cases in dry sliding conditions -∼5% with lubricating ones. (authors). 13 refs., 19 figs., 1 table

  15. Use of Textured Surfaces to Mitigate Sliding Friction and Wear of Lubricated and Non-Lubricated Contacts

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Peter Julian [ORNL

    2012-03-01

    If properly employed, the placement of three-dimensional feature patterns, also referred to as textures, on relatively-moving, load-bearing surfaces can be beneficial to their friction and wear characteristics. For example, geometric patterns can function as lubricant supply channels or depressions in which to trap debris. They can also alter lubricant flow in a manner that produces thicker load-bearing films locally. Considering the area occupied by solid areas and spaces, textures also change the load distribution on surfaces. At least ten different attributes of textures can be specified, and their combinations offer wide latitude in surface engineering. By employing directional machining and grinding procedures, texturing has been used on bearings and seals for well over a half century, and the size scales of texturing vary widely. This report summarizes past work on the texturing of load-bearing surfaces, including past research on laser surface dimpling of ceramics done at ORNL. Textured surfaces generally show most pronounced effects when they are used in conformal or nearly conformal contacts, like that in face seals. Combining textures with other forms of surface modification and lubrication methods can offer additional benefits in surface engineering for tribology. As the literature and past work at ORNL shows, texturing does not always provide benefits. Rather, the selected pattern and arrangement of features must be matched to characteristics of the proposed application, bearing materials, and lubricants.

  16. Synthesis and wear behavior of aluminum 6061 alloy reinforced with carbon nanotubes

    Science.gov (United States)

    Khalil, Abdullah

    In the present work, Al6061 alloy was uniformly reinforced with 0.5, 0.75, 1 and 2 wt. % Carbon Nanotubes (CNTs) using two way dispersion method. For consolidation, Spark Plasma Sintering (SPS) was used which resulted in very high densification for the matrix as well as composite. Results showed that addition of CNTs lead to increased hardness of the material and maximum hardness was found for 1 wt. % CNTs. So this composition was selected for detailed wear analysis. Pin-on-disk wear tests were conducted for the monolithic Al6061 and the composite at a constant speed of 0.5 m/s with varying load from 5 N to 30 N under dry sliding conditions using AISI 4140 steel disk as a counterface. The composite displayed lower wear rate and friction coefficient at lower levels of applied stress (0.175 to 0.525 MPa). Under higher stresses (0.700 to 1.050 MPa), the increased brittleness and porosity of the composite caused severe fracturing and delamination resulting in excessive wear rate and friction coefficient for the composite as compared to monolithic Al6061. The transition from mild to severe wear regime in composite occurred also at lower stress as compared to monolith. Analysis of the worn surfaces revealed abrasion as the dominant wear mechanism for both the materials at lower stresses. At higher stress levels, adhesion was found to be dominant in monolithic Al6061 whereas in composite, excessive sub-surface fracturing and delamination was mainly observed.

  17. The Influence of Social Networking Technologies on Female Religious Veil-Wearing Behavior in Iran

    Science.gov (United States)

    Shakiba, Abbas; Kwok, Justin; Montazeri, Mohammad Sadegh

    2014-01-01

    Abstract Social networking technologies can influence attitudes, behaviors, and social norms. Research on this topic has been conducted primarily among early adopters of technology and within the United States. However, it is important to evaluate how social media might affect people's behaviors in international settings, especially among countries with longstanding, government recommended, cultural and religious traditions and behaviors, such as Iran. This study seeks to assess whether Iranian women who have been using social networking technologies for a longer time (compared to those who have recently joined) would be less likely to cover themselves with a veil and be more comfortable publicly displaying pictures of this behavior on Facebook. Iranian females (N=253) were selected through snowball sampling from nongovernmental organizations in November 2011 and asked to complete a survey assessing their use of Facebook, concerns about not wearing a veil in Facebook pictures, and their actual likelihood of wearing a veil. Items were combined to measure lack of interest in wearing a veil. Length of time as a Facebook user was significantly associated with not wearing a veil (b=0.16, pbehavior of wearing a veil (b=−0.45, pSocial networking technologies can affect attitudes and behaviors internationally. We discuss methods of using social media for self-presentation and expression, as well as the difficulties (and importance) of studying use of technologies, such as social media, internationally. PMID:24611768

  18. Investigation of the Effect of Residual Stress Gradient on the Wear Behavior of PVD Thin Films

    Science.gov (United States)

    Tlili, B.; Nouveau, C.; Guillemot, G.; Besnard, A.; Barkaoui, A.

    2018-02-01

    The control of residual stresses has been seldom investigated in multilayer coatings dedicated to improvement of wear behavior. Here, we report the preparation and characterization of superposed structures composed of Cr, CrN and CrAlN layers. Nano-multilayers CrN/CrAlN and Cr/CrN/CrAlN were deposited by Physical Vapor Deposition (PVD) onto Si (100) and AISI4140 steel substrates. The Cr, CrN and CrAlN monolayers were developed with an innovative approach in PVD coatings technologies corresponding to deposition with different residual stresses levels. Composition and wear tracks morphologies of the coatings were characterized by scanning electron microscopy, high-resolution transmission electron microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, energy-dispersive x-ray spectroscopy, x-ray diffraction and 3D-surface analyzer. The mechanical properties (hardness, residual stresses and wear) were investigated by nanoindentation, interferometry and micro-tribometry (fretting-wear tests). Observations suggest that multilayer coatings are composed mostly of nanocrystalline. The residual stresses level in the films has practically affected all the physicochemical and mechanical properties as well as the wear behavior. Consequently, it is demonstrated that the coating containing moderate stresses has a better wear behavior compared to the coating developed with higher residual stresses. The friction contact between coated samples and alumina balls shows also a large variety of wear mechanisms. In particular, the abrasive wear of the coatings was a combination of plastic deformation, fine microcracking and microspallation. The application of these multilayers will be wood machining of green wood.

  19. Microstructural study and wear behavior of ductile iron surface alloyed by Inconel 617

    International Nuclear Information System (INIS)

    Arabi Jeshvaghani, R.; Jaberzadeh, M.; Zohdi, H.; Shamanian, M.

    2014-01-01

    Highlights: • The Ni-base alloy was deposited on the surface of ductile iron by TIG welding process. • Microstructure of alloyed layer consisted of carbides embedded in Ni-rich dendrite. • Hardness and wear resistance of coated sample greatly improved. • The formation of oxide layer and delamination were dominant mechanisms of wear. - Abstract: In this research, microstructure and wear behavior of Ni-based alloy is discussed in detail. Using tungsten inert gas welding process, coating of nearly 1–2 mm thickness was deposited on ductile iron. Optical and scanning electron microscopy, as well as X-ray diffraction analysis and electron probe microanalysis were used to characterize the microstructure of the surface alloyed layer. Micro-hardness and wear resistance of the alloyed layer was also studied. Results showed that the microstructure of the alloyed layer consisted of M 23 C 6 carbides embedded in Ni-rich solid solution dendrites. The partial melted zone (PMZ) had eutectic ledeburit plus martensite microstructure, while the heat affected zone (HAZ) had only a martensite structure. It was also noticed that hardness and wear resistance of the alloyed layer was considerably higher than that of the substrate. Improvement of wear resistance is attributed to the solution strengthening effect of alloying elements and also the presence of hard carbides such as M 23 C 6 . Based on worn surface analysis, the dominant wear mechanisms of alloyed layer were found to be oxidation and delamination

  20. Effect of hexagonal boron nitride and calcined petroleum coke on friction and wear behavior of phenolic resin-based friction composites

    International Nuclear Information System (INIS)

    Yi Gewen; Yan Fengyuan

    2006-01-01

    Calcined petroleum coke (CPC) and hexagonal boron nitride (h-BN) were used as the friction modifiers to improve the friction and wear properties of phenolic resin-based friction composites. Thus, the composites with different relative amounts of CPC and h-BN as the friction modifiers were prepared by compression molding. The hardness and bending strength of the friction composites were measured. The friction and wear behaviors of the composites sliding against cast iron at various temperatures were evaluated using a pin-on-disc test rig. The worn surfaces and wear debris of the friction composites were analyzed by means of scanning electron microscopy, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. It was found that the hybrid of the two friction modifiers was effective to significantly decrease the wear rate and stabilize the friction coefficient of the friction composites at various temperatures by forming a uniform lubricating and/or transferred film on the rubbing surfaces. The uniform and durable transfer films were also able to effectively diminish the direct contact between the friction composite and the cast iron counterpart and hence prevent severe wear of the latter as well. The effectiveness of the hybrid of CPC and h-BN in improving the friction and wear behavior of the phenolic resin-based friction modifiers could be attributed to the complementary action of the 'low temperature' lubricity of CPC and the 'high temperature' lubricity of h-BN. The optimum ratio of the two friction modifiers CPC and h-BN in the friction composites was suggested to be 1:1, and the corresponding friction composite showed the best friction-reducing and antiwear abilities

  1. Slide 1

    Indian Academy of Sciences (India)

    Slide 25 · Life course epidemiology and chronic diseases · Models · Slide 28 · Slide 29 · Slide 30 · New Delhi Birth Cohort · New Delhi Birth Cohort (NDBC) · Slide 33 · Slide 34 · Slide 35 · Slide 36 · Slide 37 · Slide 38 · Slide 39 · CONCLUSIONS Urban Children and Adolescents · CONCLUSIONS New Delhi Birth Cohort.

  2. Microstructure and wear behaviors of laser clad NiCr/Cr3C2-WS2 high temperature self-lubricating wear-resistant composite coating

    Science.gov (United States)

    Yang, Mao-Sheng; Liu, Xiu-Bo; Fan, Ji-Wei; He, Xiang-Ming; Shi, Shi-Hong; Fu, Ge-Yan; Wang, Ming-Di; Chen, Shu-Fa

    2012-02-01

    The high temperature self-lubricating wear-resistant NiCr/Cr3C2-30%WS2 coating and wear-resistant NiCr/Cr3C2 coating were fabricated on 0Cr18Ni9 austenitic stainless steel by laser cladding. Phase constitutions and microstructures were investigated, and the tribological properties were evaluated using a ball-on-disc wear tester under dry sliding condition at room-temperature (17 °C), 300 °C and 600 °C, respectively. Results indicated that the laser clad NiCr/Cr3C2 coating consisted of Cr7C3 primary phase and γ-(Fe,Ni)/Cr7C3 eutectic colony, while the coating added with WS2 was mainly composed of Cr7C3 and (Cr,W)C carbides, with the lubricating WS2 and CrS sulfides as the minor phases. The wear tests showed that the friction coefficients of two coatings both decrease with the increasing temperature, while the both wear rates increase. The friction coefficient of laser clad NiCr/Cr3C2-30%WS2 is lower than the coating without WS2 whatever at room-temperature, 300 °C, 600 °C, but its wear rate is only lower at 300 °C. It is considered that the laser clad NiCr/Cr3C2-30%WS2 composite coating has good combination of anti-wear and friction-reducing capabilities at room-temperature up to 300 °C.

  3. Significance of an in-situ generated boundary film on tribocorrosion behavior of polymer-metal sliding pair.

    Science.gov (United States)

    Xu, Yongkun; Qi, Huimin; Li, Guitao; Guo, Xueping; Wan, Yong; Zhang, Ga

    2018-05-15

    Polymer composites have a high potential for applications as tribo-materials exposed to sea water owing to their self-lubrication characteristic and high chemical stability. In the present work, tribological behaviors of polyetheretherketone (PEEK) composites rubbing with stainless steel in sea water were explored using a pin-on-disc tribometer integrated with a potentiostat for electrochemical control. It was demonstrated that further adding 5 vol% hexagonal boron nitride (h-BN) nanoparticles into PEEK reinforced with short carbon fibers (SCF) significantly enhanced the wear resistance. Moreover, the stainless steel exhibited significantly enhanced tribocorrosion resistance when rubbing with the hybrid nanocomposite, in comparison to the sliding against PEEK filled only with SCF. Nanostructures of the boundary films formed on the steel surface were comprehensively investigated. It was manifested that tribo-chemistry products of h-BN, i.e. H 3 BO 3 and B 2 O 3 , were arrayed in a closely packed boundary film. It seems that inclusion of layer-structured H 3 BO 3 and B 2 O 3 improved the resilience of the boundary film. The continuous boundary film covering the steel surface provided a lubrication effect and strengthened the passivation layer. A new route for enhancing simultaneously tribological and corrosion resistance of polymer-metal pairs by controlling in-situ tribo-chemistry was thus proposed. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Micro-tribological properties of hydroxyapatite-based composites in dry sliding

    International Nuclear Information System (INIS)

    Lu, Zhi; Liu, Yong; Liu, Bowei; Liu, Meiling

    2013-01-01

    Highlights: ► The micro-tribological properties of HA-based composites were investigated. ► The micro-scale test is greatly benefits to the analyses of the wear mechanism. ► A higher speed benefits the formation of the lubricating layer, when high in Cu. ► With increasing Cu, the wear mechanism shift from abrasive wear to adhesive wear. - Abstract: The micro-tribological properties of hydroxyapatite-based composites sliding against alumina balls were investigated by a ball-on-block tribometer. Surface properties of the HA-based composites were measured and examined by using atomic force microscopy and scanning electron microscopy. Running-in behavior during sliding tests was studied as a function of surface properties. The effects of copper fibers, initial surface roughness, and sliding velocity on the friction coefficient and the wear resistance were discussed. Results show that a lubricant layer benefits the tribological properties of the composites. With the increasing of Cu, the lubricant layer is more stable, and resistant to increase of the sliding velocity. At a Cu content of 15%, the wear curve is very stable even at a velocity of 900 rpm. The wear mechanism also changes from abrasive wear to adhesive wear. A model was quoted to describe the relationship between the wear resistant and the load

  5. Modular correction method of bending elastic modulus based on sliding behavior of contact point

    International Nuclear Information System (INIS)

    Ma, Zhichao; Zhao, Hongwei; Zhang, Qixun; Liu, Changyi

    2015-01-01

    During the three-point bending test, the sliding behavior of the contact point between the specimen and supports was observed, the sliding behavior was verified to affect the measurements of both deflection and span length, which directly affect the calculation of the bending elastic modulus. Based on the Hertz formula to calculate the elastic contact deformation and the theoretical calculation of the sliding behavior of the contact point, a theoretical model to precisely describe the deflection and span length as a function of bending load was established. Moreover, a modular correction method of bending elastic modulus was proposed, via the comparison between the corrected elastic modulus of three materials (H63 copper–zinc alloy, AZ31B magnesium alloy and 2026 aluminum alloy) and the standard modulus obtained from standard uniaxial tensile tests, the universal feasibility of the proposed correction method was verified. Also, the ratio of corrected to raw elastic modulus presented a monotonically decreasing tendency as the raw elastic modulus of materials increased. (technical note)

  6. Corrosion and Wear Behaviors of Cr-Doped Diamond-Like Carbon Coatings

    Science.gov (United States)

    Viswanathan, S.; Mohan, L.; Bera, Parthasarathi; Kumar, V. Praveen; Barshilia, Harish C.; Anandan, C.

    2017-08-01

    A combination of plasma-enhanced chemical vapor deposition and magnetron sputtering techniques has been employed to deposit chromium-doped diamond-like carbon (DLC) coatings on stainless steel, silicon and glass substrates. The concentrations of Cr in the coatings are varied by changing the parameters of the bipolar pulsed power supply and the argon/acetylene gas composition. The coatings have been studied for composition, morphology, surface nature, nanohardness, corrosion resistance and wear resistance properties. The changes in I D / I G ratio with Cr concentrations have been obtained from Raman spectroscopy studies. Ratio decreases with an increase in Cr concentration, and it has been found to increase at higher Cr concentration, indicating the disorder in the coating. Carbide is formed in Cr-doped DLC coatings as observed from XPS studies. There is a decrease in sp 3/ sp 2 ratios with an increase in Cr concentration, and it increases again at higher Cr concentration. Nanohardness studies show no clear dependence of hardness on Cr concentration. DLC coatings with lower Cr contents have demonstrated better corrosion resistance with better passive behavior in 3.5% NaCl solution, and corrosion potential is observed to move toward nobler (more positive) values. A low coefficient of friction (0.15) at different loads is observed from reciprocating wear studies. Lower wear volume is found at all loads on the Cr-doped DLC coatings. Wear mechanism changes from abrasive wear on the substrate to adhesive wear on the coating.

  7. Effect of surface oxidation on the nm-scale wear behavior of a metallic glass

    International Nuclear Information System (INIS)

    Caron, A.; Louzguine-Luzguin, D. V.; Sharma, P.; Inoue, A.; Shluger, A.; Fecht, H.-J.

    2011-01-01

    Metallic glasses are good candidates for applications in micromechanical systems. With size reduction of mechanical components into the micrometer and submicrometer range, the native surface oxide layer starts playing an important role in contact mechanical applications of metallic glasses. We use atomic force microscopy to investigate the wear behavior of the Ni 62 Nb 38 metallic glass with a native oxide layer and with an oxide grown after annealing in air. After the annealing, the wear rate is found to have significantly decreased. Also the dependency of the specific wear on the velocity is found to be linear in the case of the as spun sample while it follows a power law in the case of the sample annealed in air. We discuss these results in relation to the friction behavior and properties of the surface oxide layer obtained on the same alloy.

  8. Sliding wear of steels (used in polished rods of oil pump jack) against polyurethane; Desgaste de deslizamento de acos (usados em hastes de unidade de bombeio de petroleo) contra poliuretano

    Energy Technology Data Exchange (ETDEWEB)

    Gois, Gelsoneide da Silva [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Engenharia de Materiais; Farias, Aline Cristina Mendes; Lima da Silva, Ruthilene Catarina; Medeiros, Joao Telesforo Nobrega [Universidade Federal do Rio Grande do Norte (PPGEM/UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Engenharia de Materiais], e-mail: gelsoneidegg@yahoo.com.br, e-mail: alineastro@yahoo.com.br, e-mail: ruthilene@ufrnet.br, e-mail: medeirosj2@asme.org

    2008-07-01

    Accelerated sliding tests were carried out in the steels AISI 316, AISI 4140, AISI 1045 coated and AISI 4142 coated, in the dry and lubricated with contaminated oil with 10% SiO{sub 2} conditions. Each cylindrical counterbody with angular generatrix of polyurethane slid against a stationary metallic specimen. The contact pressure changed by increment of normal loads of 10,0 and 2,3 N, velocity of 0,91 m/s and distance of 12 km. The wear rates were calculated through of the mass variation from specimens after each test. The wear morphology was characterized by Optical and Scanning Electron Microscopy, where identified damages by abrasion at two and three bodies. The contaminated lubricant increase the wear rate due to action of the abrasive particles. (author)

  9. X-ray residual stress measurement and its variation during plane bending fatigue and sliding wear processes in TiC, TiN, TiB2 and Al2O3 coated carbon steels

    International Nuclear Information System (INIS)

    Endoh, Takashi; Idemitsu, Kohji; Kawakami, Mamoru

    1993-01-01

    The development of ceramic coating to metals was stimulated by the need for high temperature, wear and corrosion resistant materials. Recently TiC, TiN, TiB 2 and Al 2 O 3 are used as ceramic coating materials. In the present study, the X-ray method was successfully applied to measure the residual stress distribution in their ceramics coated steels. The X-ray elastic constants were determined and compared with the mechanically measured values. And plane bending and sliding wear tests were carried out. The X-ray method was successfully applied to measure the residual stress changes during fatigue and wear processes. The relationship between the change of residual stress and damage accumulation was investigated. (author)

  10. Experimental wear behavioral studies of as-cast and 5 hr homogenized Al25Mg2Si2Cu4Ni alloy at constant load based on taguchi method

    Science.gov (United States)

    Harlapur, M. D.; Mallapur, D. G.; Udupa, K. Rajendra

    2018-04-01

    In the present study, an experimental study of the volumetric wear behaviour of Aluminium (Al-25Mg2Si2Cu4Ni) alloy in as cast and 5Hr homogenized with T6 heat treatment is carried out at constant load. The Pin on disc apparatus was used to carry out the sliding wear test. Taguchi method based on L-16 orthogonal array was employed to evaluate the data on the wear behavior. Signal-to-noise ratio among the objective of smaller the better and mean of means results were used. General regression model is obtained by correlation. Lastly confirmation test was completed to compose a comparison between the experimental results foreseen from the mention correlation. The mathematical model reveals the load has maximum contribution on the wear rate compared to speed. Scanning Electron Microscope was used to analyze the worn-out wear surfaces. Wear results show that 5Hr homogenized Al-25Mg2Si2Cu4Ni alloy samples with T6 treated had better volumetric wear resistance as compared to as cast samples.

  11. Microstructural evolution and wear behaviors of laser cladding Ti{sub 2}Ni/α(Ti) dual-phase coating reinforced by TiB and TiC

    Energy Technology Data Exchange (ETDEWEB)

    Song, R.; Li, J., E-mail: jacob_lijun@sina.com; Shao, J.Z.; Bai, L.L.; Chen, J.L.; Qu, C.C.

    2015-11-15

    Graphical abstract: - Highlights: • A TiC+TiB reinforced intermetallic matrix coating was fabricated by laser cladding. • The microstructural evolution of the reinforcements was analyzed. • A formula was established in term of wear loss, sliding time and applied load. • Wear behaviors were investigated by in situ continuing tests in different time intervals. • The transformation of wear mechanism at different applied loads was revealed. - Abstract: The Ti{sub 2}Ni/α(Ti) dual-phase coating reinforced by TiB and TiC was fabricated on the Ti6Al4V substrate by laser cladding. Phase constituents were confirmed by a theoretical prediction combined with X-ray diffraction (XRD) analyses. From the surface to the bottom of the coating, a regular evolution of the reinforcements’ microstructure, namely TiC{sub p}+(TiB+TiC){sub e}, (TiB+TiC){sub e} and TiB{sub p}+(TiB+TiC){sub e} (p and e were the abbreviations of primary and eutectic, respectively), was investigated by scanning electron microscopy (SEM). The coating possessed the higher microhardness than that of the substrate. An in situ dynamic method (in situ continuing tests at different time intervals) was designed to reveal wear behaviors at different wear stages. A quantitative calculation formula was established by a mathematic model to predict wear losses under different sliding time and applied loads in a definite precision. The wear mechanism was transformed from brittle debonding (at 10 N) to the joint action of brittle debonding and micro-cutting (at 20 N and 30 N) due to the microstructural evolution across the depth from the surface of the coating.

  12. Effects of simulated clay gouges on the sliding behavior of Tennessee sandston

    Science.gov (United States)

    Shimamoto, Toshihiko; Logan, John M.

    1981-06-01

    The effects of simulated fault gouge on the sliding behavior of Tennessee sandstone are studied experimentally with special reference to the stabilizing effect of clay minerals mixed into the gouge. About 30 specimens with gouge composed of pure clays, of homogeneously mixed clay and anhydrite, or of layered clay and anhydrite, along a 35° precut are deformed dry in a triaxial apparatus at a confining pressure of 100 MPa, with a shortening rate of about 5 · 10 -4/sec, and at room temperature. Pure clay gouges exhibit only stable sliding, and the ultimate frictional strength is very low for bentonite (mont-morillonite), intermediate for chlorite and illite, and considerably higher for kaolinite. Anhydrite gouge shows violent stick-slip at 100 MPa confining pressure. When this mineral is mixed homogeneously with clays, the frictional coefficient of the mixed gouge, determined at its ultimate frictional strength, decreases monotonically with an increase in the clay content. The sliding mode changes from stick-slip to stable sliding when the frictional coefficient of the mixed clay-anhydrite gouge is lowered down below 90-95% of the coefficient of anhydrite gouge. The stabilizing effect of clay in mixed gouge is closely related to the ultimate frictional strength of pure clays; that is, the effect is conspicuous only for a mineral with low frictional strength. Only 15-20% of bentonite suppresses the violent stick-slip of anhydrite gouge. In contrast, violent stick-slip occurs even if the gouge contains as much as 75% of kaolinite. The behavior of illite and chlorite is intermediate between that of kaolinite and bentonite. Bentonite—anhydrite two-layer gouge exhibits stable sliding even when the bentonite content is only 5%. Thus, the presence of a thin, clay-rich layer in a fault zone stabilizes the behavior much more effectively than do the clay minerals mixed homogeneously with the gouge. This result brings out the mechanical significance of internal structures

  13. Effects of crystal refining on wear behaviors and mechanical properties of lithium disilicate glass-ceramics.

    Science.gov (United States)

    Zhang, Zhenzhen; Guo, Jiawen; Sun, Yali; Tian, Beimin; Zheng, Xiaojuan; Zhou, Ming; He, Lin; Zhang, Shaofeng

    2018-05-01

    The purpose of this study is to improve wear resistance and mechanical properties of lithium disilicate glass-ceramics by refining their crystal sizes. After lithium disilicate glass-ceramics (LD) were melted to form precursory glass blocks, bar (N = 40, n = 10) and plate (N = 32, n = 8) specimens were prepared. According to the differential scanning calorimetry (DSC) of precursory glass, specimens G1-G4 were designed to form lithium disilicate glass-ceramics with different crystal sizes using a two-step thermal treatment. In the meantime, heat-pressed lithium disilicate glass-ceramics (GC-P) and original ingots (GC-O) were used as control groups. Glass-ceramics were characterized using X-ray diffraction (XRD) and were tested using flexural strength test, nanoindentation test and toughness measurements. The plate specimens were dynamically loaded in a chewing simulator with 350 N up to 2.4 × 10 6 loading cycles. The wear analysis of glass-ceramics was performed using a 3D profilometer after every 300,000 wear cycles. Wear morphologies and microstructures were analyzed by scanning electron microscopy (SEM). One-way analysis of variance (ANOVA) was used to analyze the data. Multiple pairwise comparisons of means were performed by Tukey's post-hoc test. Materials with different crystal sizes (p properties. Specifically, G3 with medium-sized crystals presented the highest flexural strength, hardness, elastic modulus and fracture toughness. G1 and G2 with small-sized crystals showed lower flexural strength, whereas G4, GC-P, and GC-O with large-sized crystals exhibited lower hardness and elastic modulus. The wear behaviors of all six groups showed running-in wear stage and steady wear stage. G3 showed the best wear resistance while GC-P and GC-O exhibited the highest wear volume loss. After crystal refining, lithium disilicate glass-ceramic with medium-sized crystals showed the highest wear resistance and mechanical properties. Copyright © 2018

  14. Effect of gallic acid on the wear behavior of early carious enamel

    Energy Technology Data Exchange (ETDEWEB)

    Gao, S S; Huang, S B; Yu, H Y [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China); Qian, L M, E-mail: yhyang6812@scu.edu.c [Tribology Research Institute, National Traction Power Laboratory, Southwest Jiaotong University, Chengdu 610031 (China)

    2009-06-15

    The purpose of this research was to investigate the wear behavior of early carious enamel remineralized with gallic acid. Forty natural human premolar specimens with early caries lesions were prepared. A remineralization pH-cycling treatment agent of 4000 ppm gallic acid was used for 12 days to treat the early lesions. The changes in microhardness were monitored. Nanoscratch tests were used to evaluate wear resistance. The experimental data were analyzed by using a t-test. The widths of traces were measured by an AMBIOS XP-2 stylus profilometer. After remineralization, all samples re-hardened significantly. The coefficients of friction became higher, and the widths of scratches were larger than they were before remineralization. Gallic acid significantly improved the early carious enamel's hardness. The wear damage of the samples treated with gallic acid was more severe than that of the control group. There were more obvious cracks and delaminations on the traces of the treated group. Compared with the control group, the enamel remineralized with gallic acid had inferior wear resistance. After remineralization, the dominant damage mechanisms of early carious enamel had changed from plastic deformation and adhesive wear to a combination of brittle cracks and delamination of enamel.

  15. Investigation on wear behavior of graphite baII under different pneumatic conveying environments

    International Nuclear Information System (INIS)

    Chen Zhipeng; Zheng Yanhua; Shi Lei; Yu Suyuan

    2014-01-01

    An experimental platform was built in the Institute of Nuclear and New Energy Technology (INET) to investigate the wear behavior of the graphite ball under the operational condition of the high temperature gas-cooled reactor (HTGR) fuel handling system. In this experimental platform, a series of experiments were carried out under different pneumatic conveying environments with the graphite balls, which were made of the material same as the fuel element matrix graphite (A3) of the 10 MW high temperature gas cooled reactor (HTR-10). The effect of the pneumatic conveying condition on the wear rate of graphite ball has been investigated, and the results include: (1) There is an obvious linear relationship between the wear rate and the feeding velocity of graphite ball elevated in the stainless steel elevating tube, and the wear rate will increase with the increase of the feeding velocity. (2) The wear rate of graphite ball under helium environment is significantly greater than that under air and nitrogen environments, which is caused by the different effects of various gas environments on mechanical properties of graphite. (author)

  16. Effect of gallic acid on the wear behavior of early carious enamel

    International Nuclear Information System (INIS)

    Gao, S S; Huang, S B; Yu, H Y; Qian, L M

    2009-01-01

    The purpose of this research was to investigate the wear behavior of early carious enamel remineralized with gallic acid. Forty natural human premolar specimens with early caries lesions were prepared. A remineralization pH-cycling treatment agent of 4000 ppm gallic acid was used for 12 days to treat the early lesions. The changes in microhardness were monitored. Nanoscratch tests were used to evaluate wear resistance. The experimental data were analyzed by using a t-test. The widths of traces were measured by an AMBIOS XP-2 stylus profilometer. After remineralization, all samples re-hardened significantly. The coefficients of friction became higher, and the widths of scratches were larger than they were before remineralization. Gallic acid significantly improved the early carious enamel's hardness. The wear damage of the samples treated with gallic acid was more severe than that of the control group. There were more obvious cracks and delaminations on the traces of the treated group. Compared with the control group, the enamel remineralized with gallic acid had inferior wear resistance. After remineralization, the dominant damage mechanisms of early carious enamel had changed from plastic deformation and adhesive wear to a combination of brittle cracks and delamination of enamel.

  17. Dowel Behavior of Rebars in Small Concrete Block for Sliding Slab Track on Railway Bridges

    Directory of Open Access Journals (Sweden)

    Seong-Cheol Lee

    2018-01-01

    Full Text Available In recent years, several studies have investigated the sliding slab track for railway bridges. In the design of sliding slab tracks, one of the most important considerations is to evaluate the shear capacity of the lateral supporting concrete blocks in which dowel rebars are embedded. The predictions of the dowel behavior of rebars by existing models are considerably different. Therefore, in this study, the actual dowel behavior of the rebars embedded in a small concrete block was extensively investigated through experiments. Test variables were concrete compressive strength, dowel rebar diameter and yield strength, specimen thickness, and dowel rebar spacing. Existing model predictions were considerably different from test results. The maximum dowel force increased as concrete compressive strength and dowel rebar diameter increased, while it did not increase considerably with other test variables. Unlike in existing models, the shear slip at the maximum dowel force decreased as the dowel rebar diameter increased. Existing models significantly underestimated the maximum dowel force of the dowel rebars with small diameters and overestimated it for the dowel rebars with large diameters. This work can be useful for developing a more rational model to represent the actual dowel behavior of the rebars embedded in small concrete blocks.

  18. Microstructure and wear behavior of stellite 6 cladding on 17-4 PH stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Gholipour, A. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Shamanian, M., E-mail: shamanian@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Ashrafizadeh, F. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2011-04-07

    Research highlights: > The microstructure of the surface layer consisted of carbides embedded in a Co-rich solid solution with dendritic structure. Primary phases formed during the process were identified as Co(FCC) and lamellar eutectic phases (M{sub 23}C{sub 6}, M{sub 6}C, Cr{sub 7}C{sub 3}). > Microhardness profiles showed that hardness increases from interface to the coating surface. This is due to the finer size of the grains at coating surface in comparison to that at interface and also diffusion of Fe adjacent to the interface. > The delamination was suggested as the dominant mechanism of the wear. In this regard, plate-like wear debris consisted of voids and cracks. In addition, due to increase in surface temperature, Cr{sub 2}O{sub 3} oxide phase was formed during wear tests. - Abstract: This paper deals with the investigation of the microstructure and wear behavior of the stellite 6 cladding on precipitation hardening martensitic stainless steel (17-4PH) using gas tungsten arc welding (GTAW) method. 17-4 PH stainless steel is widely used in oil and gas industries. Optical metallography, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were employed to study the microstructure and wear mechanisms. X-ray diffraction analysis was also used to identify phases formed in the coating. The results showed that the microstructure of the surface layer consisted of carbides embedded in a Co-rich solid solution with a dendritic structure. In addition, the dendritic growth in the coating was epitaxial. Primary phases formed during the process were Co (fcc), Co (hcp), lamellar eutectic phases, M{sub 23}C{sub 6} and Cr{sub 7}C{sub 3} type carbides. The results of the wear tests indicated that the delamination was the dominant mechanism. So, it is necessary to apply an inter-layer between the substrate and top coat.

  19. Calculation of wear (f.i. wear modulus) in the plastic cup of a hip joint prosthesis

    NARCIS (Netherlands)

    Ligterink, D.J.

    1975-01-01

    The wear equation is applied to the wear process in a hip joint prosthesis and a wear modulus is defined. The sliding distance, wear modulus, wear volume, wear area, contact angle and the maximum normal stress were calculated and the theoretical calculations applied to test results. During the wear

  20. Effect of nanodiamond on friction and wear behavior of metal dichalcogenides in synthetic oil

    Science.gov (United States)

    Raina, Ankush; Anand, Ankush

    2018-02-01

    In this paper, experiments were conducted to study the tribological behavior of synthetic oil containing nanodiamond (ND) with molybdenum disulphide (MoS2) and tungsten disulphide (WS2) nanoparticles. The experiments were performed in boundary lubrication regime for steel/steel contacts. A ball on disc configuration was used to obtain the frictional characteristics of the lubricating oils at a constant velocity of 0.58 m/s. Scanning electron microscopy and energy dispersive spectroscopy were carried out to evaluate the wear behavior of the worn out disc samples. The results obtained from the investigation exhibited an improvement in both wear and friction coefficient. On addition of 0.2% ND in the oil containing MoS2 and WS2 nanoparticles, the coefficient of friction (COF) and wear volume decreased around two times in comparison to the PAO oil. The enhancement in overall lubrication behavior is mainly due to the synergism between the MoS2/ND and WS2/ND nanoparticles.

  1. Slide 1

    Indian Academy of Sciences (India)

    Potency of Stem Cells · Slide 3 · Slide 4 · Slide 5 · World Wide Clinical trials using MSCs · Slide 7 · Bone Marrow derived Human MSCs (hMSC) in culture · Slide 9 · Slide 10 · Slide 11 · Slide 12 · Slide 13 · Fetal MSCs · Morphology of murine fetal heart derived stem cells (fHSCs) · Growth Kinetics of fHSCs · Phenotype of ...

  2. Polymer wear evaluation

    DEFF Research Database (Denmark)

    Lagerbon, Mikkel; Sivebæk, Ion Marius

    2012-01-01

    Polymer wear plays an increasing role in manufacturing of machine parts for e.g. medical devices. Some of these have an expected lifetime of five to eight years during which very little wear of the components is acceptable. Too much wear compromises the dosage accuracy of the device and thereby...... the safety of the patients. Prediction of the wear of polymers is complicated by the low thermal conductivity of this kind of material. It implies that any acceleration of testing conditions by increased contact pressure and/or sliding velocity will make the polymer fail due to exaggerated heat buildup....... This is not the kind of wear observed in medical devices. In the present work a method was developed capable of evaluating the wear progression in polymer-polymer contacts. The configuration of the setup is injection moulded specimens consisting of an upper part having a toroid shape and a lower flat part. The sliding...

  3. Study on torsional fretting wear behavior of a ball-on-socket contact configuration simulating an artificial cervical disk

    International Nuclear Information System (INIS)

    Wang, Song; Wang, Fei; Liao, Zhenhua; Wang, Qingliang; Liu, Yuhong; Liu, Weiqiang

    2015-01-01

    A ball-on-socket contact configuration was designed to simulate an artificial cervical disk in structure. UHMWPE (ultra high molecular weight polyethylene) hot pressed by powders and Ti6Al4V alloy were selected as the material combination of ball and socket. The socket surface was coated by a ~ 500 nm C-DLC (carbon ion implantation-diamond like carbon) mixed layer to improve its surface nano hardness and wear resistance. The torsional fretting wear behavior of the ball-on-socket model was tested at different angular displacements under 25% bovine serum lubrication with an axial force of 100 N to obtain more realistic results with that in vivo. The fretting running regimes and wear damage characteristics as well as wear mechanisms for both ball and socket were studied based on 2D (two dimension) optical microscope, SEM (scanning electron microscope) and 3D (three dimension) profiles. With the increase of angular displacement amplitude from 1° to 7°, three types of T-θ (Torsional torque-angular displacement amplitude) curves (i.e., linear, elliptical and parallelogram loops) corresponding to running regimes of PSR (partial slip regime), MR (mixed regime) and SR (slip regime) were observed and analyzed. Both the central region and the edge zone of the ball and socket were damaged. The worn surfaces were characterized by wear scratches and wear debris. In addition, more severe wear damage and more wear debris appeared on the central region of the socket at higher angular displacement amplitude. The dominant damage mechanism was a mix of surface scratch, adhesive wear and abrasive wear for the UHMWPE ball while that for the coated socket was abrasive wear by PE particles and some polishing and rolling process on the raised overgrown DLC grains. The frictional kinetic behavior, wear type, damage region and damage mechanism for the ball-on-socket model revealed significant differences with those of a ball-on-flat contact while showing better consistency with that of in

  4. Study on torsional fretting wear behavior of a ball-on-socket contact configuration simulating an artificial cervical disk

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Song [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Wang, Fei [School of Material Science and Engineering, China University of Mining and Technology, Xuzhou 221116 (China); Liao, Zhenhua [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Wang, Qingliang [School of Material Science and Engineering, China University of Mining and Technology, Xuzhou 221116 (China); Liu, Yuhong [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Liu, Weiqiang, E-mail: weiqliu@hotmail.com [Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China)

    2015-10-01

    A ball-on-socket contact configuration was designed to simulate an artificial cervical disk in structure. UHMWPE (ultra high molecular weight polyethylene) hot pressed by powders and Ti6Al4V alloy were selected as the material combination of ball and socket. The socket surface was coated by a ~ 500 nm C-DLC (carbon ion implantation-diamond like carbon) mixed layer to improve its surface nano hardness and wear resistance. The torsional fretting wear behavior of the ball-on-socket model was tested at different angular displacements under 25% bovine serum lubrication with an axial force of 100 N to obtain more realistic results with that in vivo. The fretting running regimes and wear damage characteristics as well as wear mechanisms for both ball and socket were studied based on 2D (two dimension) optical microscope, SEM (scanning electron microscope) and 3D (three dimension) profiles. With the increase of angular displacement amplitude from 1° to 7°, three types of T-θ (Torsional torque-angular displacement amplitude) curves (i.e., linear, elliptical and parallelogram loops) corresponding to running regimes of PSR (partial slip regime), MR (mixed regime) and SR (slip regime) were observed and analyzed. Both the central region and the edge zone of the ball and socket were damaged. The worn surfaces were characterized by wear scratches and wear debris. In addition, more severe wear damage and more wear debris appeared on the central region of the socket at higher angular displacement amplitude. The dominant damage mechanism was a mix of surface scratch, adhesive wear and abrasive wear for the UHMWPE ball while that for the coated socket was abrasive wear by PE particles and some polishing and rolling process on the raised overgrown DLC grains. The frictional kinetic behavior, wear type, damage region and damage mechanism for the ball-on-socket model revealed significant differences with those of a ball-on-flat contact while showing better consistency with that of in

  5. Thermal Conductivity and Wear Behavior of HVOF-Sprayed Fe-Based Amorphous Coatings

    Directory of Open Access Journals (Sweden)

    Haihua Yao

    2017-10-01

    Full Text Available To protect aluminum parts in vehicle engines, metal-based thermal barrier coatings in the form of Fe59Cr12Nb5B20Si4 amorphous coatings were prepared by high velocity oxygen fuel (HVOF spraying under two different conditions. The microstructure, thermal transport behavior, and wear behavior of the coatings were characterized simultaneously. As a result, this alloy shows high process robustness during spraying. Both Fe-based coatings present dense, layered structure with porosities below 0.9%. Due to higher amorphous phase content, the coating H-1 exhibits a relatively low thermal conductivity, reaching 2.66 W/(m·K, two times lower than the reference stainless steel coating (5.85 W/(m·K, indicating a good thermal barrier property. Meanwhile, the thermal diffusivity of amorphous coatings display a limited increase with temperature up to 500 °C, which guarantees a steady and wide usage on aluminum alloy. Furthermore, the amorphous coating shows better wear resistance compared to high carbon martensitic GCr15 steel at different temperatures. The increased temperature accelerating the tribological reaction, leads to the friction coefficient and wear rate of coating increasing at 200 °C and decreasing at 400 °C.

  6. Comparison of wear behaviour and mechanical properties of as-cast Al6082 and Al6082-T6 using statistical analysis

    Science.gov (United States)

    Rani Rana, Sandhya; Pattnaik, A. B.; Patnaik, S. C.

    2018-03-01

    In the present work the wear behavior and mechanical properties of as cast A16082 and A16086-T6 were compared and analyzed using statistical analysis. The as cast Al6082 alloy was solutionized at 550°C, quenched and artificially aged at 170°C for 8hrs. Metallographic examination and XRD analysis revealed the presence of intermetallic compounds Al6Mn.Hardness of heat treated Al6082 was found to be more than as cast sample. Wear tests were carried out using Pin on Disc wear testing machine according to Taguchi L9 orthogonal array. Experiments were conducted under normal load 10-30N, sliding speed 1-3m/s, sliding distance 400,800,1200m respectively. Sliding speed was found to be the dominant factor for wear in both as cast and aged Al 6082 alloy. Sliding distance increases the wear rate up to 800m and then after it decreases.

  7. Fretting and wear behaviors of Ni/nano-WC composite coatings in dry and wet conditions

    International Nuclear Information System (INIS)

    Benea, Lidia; Başa, Sorin-Bogdan; Dănăilă, Eliza; Caron, Nadège; Raquet, Olivier; Ponthiaux, Pierre; Celis, Jean-Pierre

    2015-01-01

    Highlights: • The friction and wear properties of Ni/nano-WC composite were studied. • Nano-WC reinforcement decreased friction coefficient in dry and wet conditions. • Nano-WC reinforcement fraction was seen to be 12 wt.%. • Nanohardness increased by 27% compared to nickel without WC reinforcements. • Ennoblement of OCP corresponding to the Ni/nano-WC composite coating. - Abstract: The fretting and wear behaviors of Ni/nano-WC composite coatings were studied by considering the effect of fretting frequency of 1 Hz during 10,000 cycles, at different applied loads in dry or wet conditions. The studies were performed on a ball-on-disk tribometer and the results were compared with pure Ni coating. The nanohardness of pure Ni and Ni/nano-WC composite coatings was tested by nanoindentation technique. To evaluate the wet wear (tribocorrosion) behavior the open circuit potential (OCP) was measured before, during and after the fretting tests at room temperature in the solution that simulates the primary water circuit of Pressurized Water Reactors (PWRs). The results show that Ni/nano-WC composite coatings exhibited a low friction coefficient, high nanohardness and wear resistance compared with pure Ni coatings under similar experimental conditions. Ni/nano-WC composite coatings were obtained on stainless steel support by electrochemical codeposition of nano-sized WC particles (diameter size of ∼60 nm) with nickel, from a standard nickel Watts plating bath. The surface morphology and the composition of the coatings were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX) respectively

  8. Influence of heat treatment on the wear life of hydraulic fracturing tools

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Chao; Liu, Yonghong; Wang, Hanxiang; Qin, Jie; Shen, Yang; Zhang, Shihong [China University of Petroleum, Qingdao (China)

    2017-02-15

    Wear phenomenon has caused severe damage or failure of fracturing tools in oil and gas industry. In this paper, influence of heat treatment on the mechanical properties and wear resistance of fracturing tool made of lamellar graphite grey cast iron were investigated. The surface composition and microstructure were characterized by X-ray diffraction (XRD) and metallographic microscope. Sliding wear tests were performed to study the tribological behavior. Tests results showed that wear rates of treated specimens decreased by 33 %. Besides, worn morphology and wear debris were analyzed using Scanning electron microscope (SEM) and Energy dispersive Xray spectra (EDS). Wear failure mechanisms of specimens were identified. Furthermore, on-site experiment results indicated that wear loss of treated samples decreased by 37.5 %. The wear life of hydraulic fracturing tools can be improved obviously by the heat treatment.

  9. Influence of heat treatment on the wear life of hydraulic fracturing tools

    International Nuclear Information System (INIS)

    Zheng, Chao; Liu, Yonghong; Wang, Hanxiang; Qin, Jie; Shen, Yang; Zhang, Shihong

    2017-01-01

    Wear phenomenon has caused severe damage or failure of fracturing tools in oil and gas industry. In this paper, influence of heat treatment on the mechanical properties and wear resistance of fracturing tool made of lamellar graphite grey cast iron were investigated. The surface composition and microstructure were characterized by X-ray diffraction (XRD) and metallographic microscope. Sliding wear tests were performed to study the tribological behavior. Tests results showed that wear rates of treated specimens decreased by 33 %. Besides, worn morphology and wear debris were analyzed using Scanning electron microscope (SEM) and Energy dispersive Xray spectra (EDS). Wear failure mechanisms of specimens were identified. Furthermore, on-site experiment results indicated that wear loss of treated samples decreased by 37.5 %. The wear life of hydraulic fracturing tools can be improved obviously by the heat treatment

  10. Microstructure, Wear Behavior and Corrosion Resistance of WC-FeCrAl and WC-WB-Co Coatings

    Directory of Open Access Journals (Sweden)

    Janette Brezinová

    2018-05-01

    Full Text Available The paper is focused on investigating the quality of two grades of thermally sprayed coatings deposited by high-velocity oxygen fuel (HVOF technology. One grade contains WC hard particles in an environmentally progressive Ni- and Co-free FeCrAl matrix, while the second coating contains WC and WB hard particles in a cobalt matrix. The aim of the experimental work was to determine the effect of thermal cyclic loading on the coatings’ resistance to adhesive, abrasive and erosive wear. Abrasive wear was evaluated using abrasive cloth of two grit sizes, and erosive wear was evaluated by a dry-pot wear test in a pin mill at two sample angles. Adhesion wear resistance of the coatings was determined by a sliding wear test under dry friction conditions and in a 1 mol water solution of NaCl. Corrosion resistance of the coatings was evaluated using potentiodynamic polarization tests. Metallographic cross-sections were used for measurement of the microhardness and thickness and for line energy-dispersive X-ray (EDX analysis. The tests proved the excellent resistance of both coatings against adhesive, abrasive, and erosive wear, as well as the ability of the WC-WB-Co coating to withstand alternating temperatures of up to 600 °C. The “green carbide” coating (WC-FeCrAl can be recommended as an environmentally friendly replacement for Ni- and Co-containing coatings, but its operating temperature is strictly limited to 500 °C in air.

  11. Tribological characteristics of Si3N4-based composites in unlubricated sliding against steel ball

    International Nuclear Information System (INIS)

    Liu, C.-C.; Huang, J.-L.

    2004-01-01

    The dry-sliding wear mechanism of Si 3 N 4 -based composites against AISI-52100 steel ball was studied using a ball-on-disc mode in a reciprocation motion. The addition of TiN particles can increase the fracture toughness of Si 3 N 4 -based composites. The fracture toughness of Si 3 N 4 -based composites played an important role for wear behavior. The Si 3 N 4 -based composites exhibits a small friction and wear coefficient compared to monolithic Si 3 N 4 . Atomic force microscopy (AFM) studies displayed fine wear grooves along the sliding traces. The subsurface deformation shows that the microcrack propagation extends along the TiN/Si 3 N 4 grain interface. The wear mechanisms were determined with scanning electron microscopy, transmission electron microscopy, X-ray diffraction and atomic force microscopy

  12. Effects of sintering temperature on the microstructural evolution and wear behavior of WCp reinforced Ni-based coatings

    Science.gov (United States)

    Chen, Chuan-hui; Bai, Yang; Ye, Xu-chu

    2014-12-01

    This article focuses on the microstructural evolution and wear behavior of 50wt%WC reinforced Ni-based composites prepared onto 304 stainless steel substrates by vacuum sintering at different sintering temperatures. The microstructure and chemical composition of the coatings were investigated by X-ray diffraction (XRD), differential thermal analysis (DTA), scanning and transmission electron microscopy (SEM and TEM) equipped with energy-dispersive X-ray spectroscopy (EDS). The wear resistance of the coatings was tested by thrust washer testing. The mechanisms of the decomposition, dissolution, and precipitation of primary carbides, and their influences on the wear resistance have been discussed. The results indicate that the coating sintered at 1175°C is composed of fine WC particles, coarse M6C (M=Ni, Fe, Co, etc.) carbides, and discrete borides dispersed in solid solution. Upon increasing the sintering temperature to 1225°C, the microstructure reveals few incompletely dissolved WC particles trapped in larger M6C, Cr-rich lamellar M23C6, and M3C2 in the austenite matrix. M23C6 and M3C2 precipitates are formed in both the γ/M6C grain boundary and the matrix. These large-sized and lamellar brittle phases tend to weaken the wear resistance of the composite coatings. The wear behavior is controlled simultaneously by both abrasive wear and adhesive wear. Among them, abrasive wear plays a major role in the wear process of the coating sintered at 1175°C, while the effect of adhesive wear is predominant in the coating sintered at 1225°C.

  13. Microstructure analysis and wear behavior of titanium cermet femoral head with hard TiC layer.

    Science.gov (United States)

    Luo, Yong; Ge, Shirong; Liu, Hongtao; Jin, Zhongmin

    2009-12-11

    Titanium cermet was successfully synthesized and formed a thin gradient titanium carbide coating on the surface of Ti6Al4V alloy by using a novel sequential carburization under high temperature, while the titanium cermet femoral head was produced. The titanium cermet phase and surface topography were characterized with X-ray diffraction (XRD) and backscattered electron imaging (BSE). And then the wear behavior of titanium cermet femoral head was investigated by using CUMT II artificial joint hip simulator. The surface characterization indicates that carbon effectively diffused into the titanium alloys and formed a hard TiC layer on the Ti6Al4V alloys surface with a micro-porous structure. The artificial hip joint experimental results show that titanium cermet femoral head could not only improve the wear resistance of artificial femoral head, but also decrease the wear of UHMWPE joint cup. In addition, the carburized titanium alloy femoral head could effectively control the UHMWPE debris distribution, and increase the size of UHMWPE debris. All of the results suggest that titanium cermet is a prospective femoral head material in artificial joint.

  14. Effect of Cu content on wear resistance and mechanical behavior of Ti-Cu binary alloys

    Science.gov (United States)

    Yu, Feifei; Wang, Hefeng; Yuan, Guozheng; Shu, Xuefeng

    2017-04-01

    Arc melting with nonconsumable tungsten electrode and water-cooled copper crucible was used to fabricate Ti-Cu binary alloys with different Cu contents in an argon atmosphere. The compositions and phase structures of the fabricated alloys were investigated by glow discharge optical emission spectroscopy (GDOES) and X-ray diffraction (XRD). Nanoindentation tests through continuous stiffness measurement were then performed at room temperature to analyze the mechanical behaviors of the alloys. Results indicated that the composition of each Ti-Cu binary alloy was Ti(100- x) Cu x ( x = 43, 60, 69, and 74 at.%). The XRD analysis results showed that the alloys were composed of different phases, indicating that different Cu contents led to the variations in alloy hardness. The wear tests results revealed that elemental Cu positively affects the wear resistance properties of the Ti-Cu alloys. Nanoindentation testing results showed that the moduli of the Ti-Cu alloys were minimally changed at increasing Cu content, whereas their hardness evidently increased according to the wear test results.

  15. Friction and wear behavior of Inconel 625 with Ni3Ti, TiN, TiC-CVD coatings in an HTGR environment

    International Nuclear Information System (INIS)

    Sarosiek, A.M.; Li, C.C.

    1984-04-01

    The following conclusions apply to Inconel 625 with Ni 3 Ti, TiN, TiC-CVD coatings, tested in an HTGR environment in a temperature range between 500 and 900 0 C at a contact pressure of 3.45 MPa. The average wear rate is very small varying between 0.0 and 1.7 x 10 -4 g/m. The wear rate shows little dependence on temperature and sliding velocity, increasing slightly as the temperature increases or as the sliding velocity decreases. Damage experienced by wear areas is minimal. Stick-slip friction was observed at low sliding velocity, however the friction coefficient is low (maximum 0.63) with an average value of about 0.44. The friction coefficient shows little dependence on temperature and sliding velocity, increasing slightly as the temperature increases, or as the sliding velocity decreases. Ni 3 Ti, TiN, TiC-CVD coatings, are considered effective in minimizing friction and wear damage of Inconel 625 in an HTGR environment

  16. Effect of Deep Cryogenic Treatment on Hardness and Wear Behavior of 5120 AISI Steel

    Directory of Open Access Journals (Sweden)

    S. Torkian

    2016-12-01

    Full Text Available In this paper the effect of deep cryogenic treatment time on microstructure and tribological behavior of AISI 5120 case hardennig steel is studied. The disk shape samples were carburized at 920 ◦C for 6 hours and air cooled; after austenitizing, the samples were quenched in oil.Then immediately after quenching and sanding, the sample were kept in liquid nitrogen for 1, 24, 30 and 48 h and then tempered at 200 ◦C for 2 hours. The wear test was done by ball on disk method using of WC ball at 80 and 110 N load. For characterization of carbides, the etchant solution of CuCl2 (5 gr+HCl (100 mL + ethanol (100 mL was used. The hardness of samples before and after of tempering was measured by vicers method at 300 N load.. The amount of retained austenite was measured by X Ray Diffraction method. For 1DCT and 24DCT samples it was about 8% and 4%; in the other samples, the retained austenite peal was so decreased that it was not visible. The result showed that the hardness increases by deep cryogenic treatment in all speciments. While wear resistance increases in 1DCT and 24DCT samples, it decreases for 30DCT and 48DCT samples in compare with Conventional heat treatment (CHT sample in both applied loads, such that , 48DCT sample has the least wear resistance. The cause of increament of hardness is due to reduction in amount of retained austenite as a result of deep cryogenic treatment and decreasing in wear resistance after 24 hour, is due to carbide growth and nonhemogenuse distribution in microstructure and then weakening of matrix. So the 24 hour deep cryogenic treatment was the best optimal for AISI 5120 steel.

  17. Structure and wear behavior of AlCrSiN-based coatings

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yun [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Chengdu Tool Research Institute Co., Ltd., Chengdu 610500 (China); Du, Hao [School of Manufacturing Science and Engineering, Sichuan University, Chengdu 610065 (China); Chen, Ming, E-mail: mchen@sjtu.edu.cn [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Yang, Jun [Chengdu Tool Research Institute Co., Ltd., Chengdu 610500 (China); Xiong, Ji [School of Manufacturing Science and Engineering, Sichuan University, Chengdu 610065 (China); Zhao, Haibo [The Analysis and Testing Centre, Sichuan University, Chengdu 610065 (China)

    2016-05-01

    Graphical abstract: - Highlights: • AlCrSiN based coating showed amorphous structure. • AlCrSiN/Me{sub x}N coatings obtained better wear resistance. • Molybdenum and niobium increased the coating hardness and wear resistance. - Abstract: AlCrN, AlCrSiCN, AlCrSiN/MoN, and AlCrSiN/NbN coatings have been deposited on high-polished WC–Co cemented carbide substrate and tools by mid-frequency magnetron sputtering in Ar/N{sub 2} mixtures. Al{sub 0.6}Cr{sub 0.4}, Al{sub 0.6}Cr{sub 0.3}Si{sub 0.1}, and C/Mo/Nb targets were used during the deposition. The microstructure and mechanical properties of as-deposited coatings were investigated. Investigations of the wear behaviors of coated tools were also performed. The results showed that cubic structure was formed in the coatings. Broader CrAlN (1 1 1) and (2 0 0) peaks without SiN{sub x} peak were formed in the AlCrSiN/Me{sub x}N coatings, which showed a nanocomposited structure. Meanwhile, according to SEM micrographs, AlCrN exhibited a columnar structure, while, AlCrSiCN, AlCrSiN/MoN, and AlCrSiN/NbN coatings showed nanocrystalline morphology. The nano-multilayered coatings performed higher hardness, H/E, and H{sup 3}/E{sup 2} ratios compared with AlCrN coating. Through the Rockwell adhesion test, all the coatings exhibited adhesion strength quality HF1. After turning Inconel 718 under dry condition, the nano-multilyered coatings showed better wear resistance than AlCrN coating. Due to the molybdenum and niobium in the coating, AlCrSiN/MoN and AlCrSiN/NbN coatings showed the best wear resistance.

  18. Effect of the post heat treatment on the sliding wear resistance of a nickel base coating deposited by high velocity oxyl-fuel (HVOF)

    International Nuclear Information System (INIS)

    Cadenas, P.; Rodriguez, M.; Staia, M. H.

    2007-01-01

    In the present research, a nickel base coating was deposited on an AISI 1020 substrate by using high velocity oxy-fuel technique (HVOF). The coating was subsequently post heat-treated by means of an oxyacetylene flame. For the conditions evaluated in the present study, it was found that the CTT coating coating has 1,15 better wear resistance for the smaller level of the applied load and nearly 50 times for the highest level of the applied load when compared to the STT coatings. These results have been attributed to a better distribution of the hard phases, better cohesion between particles and an increase in hardness, as consequence of the post heat treatment process. A severe wear regime was found for all the samples since the wear rates presented values which were higher tan 1.10''-5 mm''3/m. For the CT T coatings, the wear mechanisms was mainly due to the adhesion and oxidation phenomena, meanwhile for the steel counterpart mechanisms such oxidation, grooving and three body abrasion were observed. (Author) 22 refs

  19. Influences of precursor constitution and processing speed on microstructure and wear behavior during laser clad composite coatings on γ-TiAl intermetallic alloy

    International Nuclear Information System (INIS)

    Liu Xiubo; Yu Rongli

    2009-01-01

    The effects of constitution of precursor mixed powders and scan speed on microstructure and wear properties were designed and investigated during laser clad γ/Cr 7 C 3 /TiC composite coatings on γ-TiAl intermetallic alloy substrates with NiCr-Cr 3 C 2 precursor mixed powders. The results indicate that both the constitution of the precursor mixed powders and the beam scan rate have remarkable influence on microstructure and attendant hardness as well as wear resistance of the formed composite coatings. The wear mechanisms of the original TiAl alloy and laser clad composite coatings were investigated. The composite coating with an optimum compromise between constitution of NiCr-Cr 3 C 2 precursor mixed powders as well as being processed under moderate scan speed exhibits the best wear resistance under dry sliding wear test conditions

  20. Friction and wear of carbon-graphite materials for high-energy brakes

    Science.gov (United States)

    Bill, R. C.

    1978-01-01

    Caliper type brake simulation experiments were conducted on seven different carbon graphite materials formulations against a steel disk material and against a carbon graphite disk material. The effects of binder level, boron carbide (B4C) additions, SiC additions, graphite fiber additions, and graphite cloth reinforcement on friction and wear behavior were investigated. Reductions in binder level, additions of B4C, and additions of SiC each resulted in increased wear. The wear rate was not affected by the addition of graphite fibers. Transition to severe wear and high friction was observed in the case of graphite-cloth-reinforced carbon sliding against a disk of similar composition. The transition was related to the disruption of a continuous graphite shear film that must form on the sliding surfaces if low wear is to occur.

  1. Friction and wear of carbon-graphite materials for high energy brakes

    Science.gov (United States)

    Bill, R. C.

    1975-01-01

    Caliper-type brakes simulation experiments were conducted on seven different carbon-graphite material formulations against a steel disk material and against a carbon-graphite disk material. The effects of binder level, boron carbide (B4C) additions, graphite fiber additions, and graphite cloth reinforcement on friction and wear behavior were investigated. Reductions in binder level and additions of B4C each resulted in increased wear. The wear rate was not affected by the addition of graphite fibers. Transition to severe wear and high friction was observed in the case of graphite-cloth-reinforced carbon sliding against a disk of similar composition. This transition was related to the disruption of a continuous graphite shear film that must form on the sliding surfaces if low wear is to occur. The exposure of the fiber structure of the cloth constituent is believed to play a role in the shear film disruption.

  2. Cast bulk metallic glass alloys: prospects as wear materials

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey A.; Dogan, Omer N.; Shiflet, Gary J. (Dept. of Materials Science and Engineering, University of Virginia, Charlottesville, VA)

    2005-01-01

    Bulk metallic glasses are single phase materials with unusual physical and mechanical properties. One intriguing area of possible use is as a wear material. Usually, pure metals and single phase dilute alloys do not perform well in tribological conditions. When the metal or alloy is lightweight, it is usually soft leading to galling in sliding situations. For the harder metals and alloys, their density is usually high, so there is an energy penalty when using these materials in wear situations. However, bulk metallic glasses at the same density are usually harder than corresponding metals and dilute single phase alloys, and so could offer better wear resistance. This work will discuss preliminary wear results for metallic glasses with densities in the range of 4.5 to 7.9 g/cc. The wear behavior of these materials will be compared to similar metals and alloys.

  3. Corrosion and wear behavior of functionally graded Al2024/SiC composites produced by hot pressing and consolidation

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, Fatih; Canakci, Aykut, E-mail: aykut@ktu.edu.tr; Varol, Temel; Ozkaya, Serdar

    2015-09-25

    Highlights: • Functionally graded Al2024/SiC composites were produced by hot pressing. • Effect of the number of graded layers was investigated on the corrosion behavior. • Functionally graded composites has the most corrosion resistant than composites. • Wear mechanisms of Al2024/SiC composites were explained. - Abstract: Functionally graded Al2024/SiC composites (FGMs) with varying percentage of SiC (30–60%) were produced by hot pressing and consolidation method. The effects of SiC content and number of layers of Al2024/SiC FGMs on the corrosion and wear behaviors were investigated. The microstructures of these composites were characterized by a scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS). The corrosion performances of composites were evaluated by potentiodynamic polarization scans in 3.5% NaCl solution. Corrosion experiments shows that corrosion rate (1109 mpy) of two layered FGMs which containing 50 wt.% SiC were much higher than Al2024 matrix (2569 mpy) and Al2024/50 wt.% SiC composite (2201 mpy). Mechanical properties of these composites were evaluated by microhardness measurements and ball-on-disk wear tests. As the applied load change from 15 to 20 N, the wear rates of the Al2024 increased significantly and wear mechanism transformed from mild to severe wear regime. It has been shown that Al2024/40 wt.% SiC composite has lower wear rate where adhesive and abrasive wear mechanisms play a major role.

  4. Creep to inertia dominated stick-slip behavior in sliding friction modulated by tilted non-uniform loading

    Science.gov (United States)

    Tian, Pengyi; Tao, Dashuai; Yin, Wei; Zhang, Xiangjun; Meng, Yonggang; Tian, Yu

    2016-09-01

    Comprehension of stick-slip motion is very important for understanding tribological principles. The transition from creep-dominated to inertia-dominated stick-slip as the increase of sliding velocity has been described by researchers. However, the associated micro-contact behavior during this transition has not been fully disclosed yet. In this study, we investigated the stick-slip behaviors of two polymethyl methacrylate blocks actively modulated from the creep-dominated to inertia-dominated dynamics through a non-uniform loading along the interface by slightly tilting the angle of the two blocks. Increasing the tilt angle increases the critical transition velocity from creep-dominated to inertia-dominated stick-slip behaviors. Results from finite element simulation disclosed that a positive tilt angle led to a higher normal stress and a higher temperature on blocks at the opposite side of the crack initiating edge, which enhanced the creep of asperities during sliding friction. Acoustic emission (AE) during the stick-slip has also been measured, which is closely related to the different rupture modes regulated by the distribution of the ratio of shear to normal stress along the sliding interface. This study provided a more comprehensive understanding of the effect of tilted non-uniform loading on the local stress ratio, the local temperature, and the stick-slip behaviors.

  5. Crack and wear behavior of SiC particulate reinforced aluminium based metal matrix composite fabricated by direct metal laser sintering process

    International Nuclear Information System (INIS)

    Ghosh, Subrata Kumar; Saha, Partha

    2011-01-01

    In this investigation, crack density and wear performance of SiC particulate (SiCp) reinforced Al-based metal matrix composite (Al-MMC) fabricated by direct metal laser sintering (DMLS) process have been studied. Mainly, size and volume fraction of SiCp have been varied to analyze the crack and wear behavior of the composite. The study has suggested that crack density increases significantly after 15 volume percentage (vol.%) of SiCp. The paper has also suggested that when size (mesh) of reinforcement increases, wear resistance of the composite drops. Three hundred mesh of SiCp offers better wear resistance; above 300 mesh the specific wear rate increases significantly. Similarly, there has been no improvement of wear resistance after 20 vol.% of reinforcement. The scanning electron micrographs of the worn surfaces have revealed that during the wear test SiCp fragments into small pieces which act as abrasives to result in abrasive wear in the specimen.

  6. Preliminary Study on the Fretting Wear Behaviors of a Duel Cooled Fuel Rod

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y.H.; Lee, K.H.; Kim, H.K. [KAERI, 150 Dukjin-dong Yuseon-gu Daejeon, 305-353 (Korea, Republic of)

    2009-06-15

    Based on MIT's concept, an innovative fuel development project was launched by KAERI that a substantial power up-rating could be realized by introducing an internally and externally double cooled annular fuel for current PWR reactors. In order to apply this duel cooled fuel to an OPR 1000 reactor system, geometrical features of structural parts in a fuel assembly should be changed except an overall dimension of a fuel assembly. Typical changes are summarized as fuel rod diameter and weight, shape and position of a spacer grid spring, etc. When considering a duel cooled fuel rod, its vibration characteristic and fretting behavior should be verified because the modified shape and dimension of spacer grid spring, fuel rod diameter and weight, number of spacer grid assembly are closely related to a flow-induced vibration in a duel cooled fuel assembly. In this study, based on FIV test results of 4x4 fuel assembly, fretting wear tests of an outer duel cooled fuel rod were performed by using an embossing type spacer grid spring that could adjust its spring stiffness. The discussion was focused on the evaluation of the optimized spring stiffness and spring position in 1x1 cell by analyzing the fretting wear results. (authors)

  7. Seat-belt wearing and driving behavior: an instrumented-vehicle study.

    Science.gov (United States)

    Janssen, W

    1994-04-01

    Less-than-expected fatality reductions after seat-belt legislation has been introduced in a jurisdiction may be explained in terms of selective recruitment of parts of the driving population and/or behavioral adaptation by beginning belt users. The present investigation has compared the relative merits of these two hypotheses at the level of individual driver behavior. In the initial study the driving behavior of groups of habitual wearers and nonwearers of the belt was compared. Nonwearers made two trips, one with the belt on and one without the belt. Habitual wearers drove belted only. The main part of the experiment was a 105 km freeway route. Two additional tasks of a somewhat more critical nature, a double lane-change manoeuvre and the performance of a braking manoeuvre in front of a fixed obstacle, were performed after the freeway trips. Factor analysis on 39 variables describing driving behavior on the road and during the additional tasks resulted in five factors. One of these, the factor describing the distribution of driving speed on the freeway, differentiated between nonwearers and wearers (thus yielding support for the selective recruitment hypothesis) as well as between wearing and not wearing the belt by the same drivers (thus yielding support for the behavioral adaptation hypothesis). In the follow-up study the original wearers and nonwearers were assigned to one of four experimental treatments: (i) the promise by the experimenter of a considerable incentive for not having a culpable motor vehicle accident over a period of a year. Half the habitual wearer subjects were assigned to this condition. The expectation was that this group would become more careful in their driving; (ii) a control group, consisting of the remaining habitual wearers; (iii) the agreement between the experimenter and the subject that the latter would buckle up in everyday driving for the year to come--half the habitual nonwearer subjects were assigned to this condition; (iv) a

  8. Microstructure and wear behavior of γ/Al4C3/TiC/CaF2 composite coating on γ-TiAl intermetallic alloy prepared by Nd:YAG laser cladding

    International Nuclear Information System (INIS)

    Liu Xiubo; Shi Shihong; Guo Jian; Fu Geyan; Wang Mingdi

    2009-01-01

    As a further step in obtaining high performance elevated temperature self-lubrication anti-wear composite coatings on TiAl alloy, a novel Ni-P electroless plating method was adopted to encapsulate the as-received CaF 2 in the preparation of precursor NiCr-Cr 3 C 2 -CaF 2 mixed powders with an aim to decrease its mass loss and increase its compatibility with the metal matrix during a Nd:YAG laser cladding. The microstructure of the coating was examined using X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) and the friction and wear behavior of the composite coatings sliding against the hardened 0.45% C steel ring was evaluated using a block-on-ring wear tester at room temperature. It was found that the coating had a unique microstructure consisting of primary dendrites TiC and block Al 4 C 3 carbides reinforcement as well as fine isolated spherical CaF 2 solid lubrication particles uniformly dispersed in the NiCrAlTi (γ) matrix. The good friction-reducing and anti-wear abilities of the laser clad composite coating was suggested to the Ni-P electroless plating and the attendant reduction of mass loss of CaF 2 and the increasing of it's wettability with the NiCrAlTi (γ) matrix during the laser cladding process

  9. Stick-slip friction and wear of articular joints

    Science.gov (United States)

    Lee, Dong Woog; Banquy, Xavier; Israelachvili, Jacob N.

    2013-01-01

    Stick-slip friction was observed in articular cartilage under certain loading and sliding conditions and systematically studied. Using the Surface Forces Apparatus, we show that stick-slip friction can induce permanent morphological changes (a change in the roughness indicative of wear/damage) in cartilage surfaces, even under mild loading and sliding conditions. The different load and speed regimes can be represented by friction maps—separating regimes of smooth and stick-slip sliding; damage generally occurs within the stick-slip regimes. Prolonged exposure of cartilage surfaces to stick-slip sliding resulted in a significant increase of surface roughness, indicative of severe morphological changes of the cartilage superficial zone. To further investigate the factors that are conducive to stick-slip and wear, we selectively digested essential components of cartilage: type II collagen, hyaluronic acid (HA), and glycosaminoglycans (GAGs). Compared with the normal cartilage, HA and GAG digestions modified the stick-slip behavior and increased surface roughness (wear) during sliding, whereas collagen digestion decreased the surface roughness. Importantly, friction forces increased up to 2, 10, and 5 times after HA, GAGs, and collagen digestion, respectively. Also, each digestion altered the friction map in different ways. Our results show that (i) wear is not directly related to the friction coefficient but (ii) more directly related to stick-slip sliding, even when present at small amplitudes, and that (iii) the different molecular components of joints work synergistically to prevent wear. Our results also suggest potential noninvasive diagnostic tools for sensing stick-slip in joints. PMID:23359687

  10. Effect of vanadium of mechanical behavior, machinability and wear resistance of aluminium grain refined by Ti+B

    International Nuclear Information System (INIS)

    Zaid, A.I.O.; Hamid, A.A.A.

    1999-01-01

    It is well established that aluminum and its alloys are industrially grain refined by adding either Ti or Ti-B to improve their mechanical behavior and surface finish. In a previous paper, it was found that the grain refining efficiency of aluminum master alloys containing Ti or Ti+B was enhanced by addition of small amounts of other elements including vanadium. V. Therefore, it is anticipated that such an element will improve mechanical behavior, machinability and wear resistance of aluminum and its alloys. In this paper, the effect of vanadium addition, up to 0.3% on mechanical behavior is investigated. Machinability was assessed under different cutting conditions: speed, feed and depth of cut and finally the wear resistance was determined at different loads and speeds. The results indicated that improvement in hardness and mechanical strength were achieved by the addition of V that addition of more than 0.2%V resulted in little or no improvement. Similarly, addition of V resulted in improvement of surface quality under the different cutting conditions of speed, feed and depth of cut, and resistance to wear. However addition of more than 0.2% V resulted in increase of wear rate and change of wear mechanisms. (author)

  11. Role of hybrid ratio in microstructural, mechanical and sliding wear properties of the Al5083/Graphitep/Al2O3p a surface hybrid nanocomposite fabricated via friction stir processing method

    International Nuclear Information System (INIS)

    Mostafapour Asl, A.; Khandani, S.T.

    2013-01-01

    Hybrid ratio of each reinforcement phase in hybrid composite can be defined as proportion of its volume to total reinforcement volume of the composite. The hybrid ratio is an important factor which controls the participation extent of each reinforcement phase in overall properties of hybrid composites. Hence, in the present work, surface hybrid nanocomposites of Al5083/Graphite p /Al 2 O 3p with different hybrid ratios were fabricated by friction stir processing method. Subsequently, effect of hybrid ratio on microstructural, mechanical and tribological properties of the nanocomposite was investigated. Optical microscopy and scanning electron microscopy were utilized to perform microstructural observation on the samples. Hardness value measurements, tensile and pin on disk dry sliding wear tests were carried out to investigate effect of hybrid ratio on mechanical and tribological properties of the nanocomposites. Microstructural investigations displayed better distribution with less agglomeration of reinforcement for lower volume fraction of reinforcement for both alumina and graphite particles. Hardness value, yield strength, ultimate tensile strength and wear rate of the nanocomposites revealed a two stage form along with hybrid ratio variation. The results are discussed based on microstructural observations of the nanocomposites and worn surface analyses.

  12. Microstructure and wear behaviors of WC–12%Co coating deposited on ductile iron by electric contact surface strengthening

    International Nuclear Information System (INIS)

    Qi, Xiaoben; Zhu, Shigen; Ding, Hao; Zhu, Zhengkun; Han, Zhibing

    2013-01-01

    WC–12%Co powders deposited on ductile iron by electric contact strengthening were studied. This technology was based on the application of the contact resistance heating between the electrode and work piece to form a wear resistant layer on ductile iron. The microstructure, microhardness distribution, phase transformation and wear behaviors of the coating were investigated using optical microscope, scanning electron microscope, Vickers hardness (HV 0.5 ), X-ray diffraction, rolling contact wear tests. The results showed that the WC–12%Co coating by electric contact strengthening was metallurgically bonded to the ductile iron. Additionally, the effect of experimental parameters on microhardness and wear resistance of coatings were studied using orthogonal experiment. The results showed that compared with (A) electric current and (B) rotating speed, (C) contact force displays the most significant effect on microhardness and wear resistance of coatings. The coatings produced at A = 19 kA, B = 0.3 r/min and C = 700 N possessed highest microhardness of 1073 HV 0.5 and wear resistance.

  13. A Possible Link Between Macroscopic Wear and Temperature Dependent Friction Behaviors of MoS2 Coatings

    Science.gov (United States)

    2008-09-01

    measured during operation without breaking the gas environment. For this study, coatings were deposited on 304 stainless steel spheres and rectangular...activated behavior in macroscopic tribology is reserved for systems with stable interfaces and ultra-low wear, and athermal behavior is characteristic to...efforts to measure and under- stand tribological behavior at cryogenic temperatures; to date, results of these efforts show either no trend or con- flicting

  14. Tribological and wear behavior of yttria stabilized zirconia thermal barrier coatings on mild steel

    International Nuclear Information System (INIS)

    Farooq, M.; Pervez, A.

    2012-01-01

    The perfection of the temperature confrontation of the engine essentials can be obtained by claim of a single ceramic thermal barrier coating (TBC) or several composite layers. Engine elements protected by TBC can work safely in elevated temperature range above 1000 degree C. Continuous endeavor to increase thermal resistance of engine the elements requires, apart from laboratory investigations, also numerical study of the different engine parts. The high temperatures and stress concentrations can act as the local sources of damage initiation and defects propagation in the form of cracks. The current study focuses the development of Yttria stabilized zirconia thermal barrier coating by Thermal spray technique. Mild steel was used as a substrate and the coating was then characterized for tribological analysis followed by the optical analysis of wear tracks and found the TBC behavior more promising then steel. (author)

  15. Dynamic study of a sliding interface wear process of TiAlN and CrN multi-layers by X-ray absorption

    DEFF Research Database (Denmark)

    Rasmussen, Inge Lise; Guibert, M.; Belin, M.

    reactions at the interface. The basic physical and chemical processes on the nano-scale are, however, not yet known fully. Thus, the work presented here is a contribution to the knowledge of the area. The main objectives of this dynamical investigation are to show that real time and in-situ tribology...... in France. The contact under investigation (TiAlN/CrN/TiAlN (2000nm/1000nm/2000nm) multi-layer system) was exposed to a reciprocating sliding motion under a normal load. Simultaneously, the contact zone was submitted to a direct, focused and monochromatic SR photon beam. In this way we have studied...

  16. Effect of sintering temperature and boron carbide content on the wear behavior of hot pressed diamond cutting segments

    Directory of Open Access Journals (Sweden)

    Islak S.

    2015-01-01

    Full Text Available The aim of this study was to investigate the effect of sintering temperature and boron carbide content on wear behavior of diamond cutting segments. For this purpose, the segments contained 2, 5 and 10 wt.% B4C were prepared by hot pressing process carried out under a pressure of 35 MPa, at 600, 650 and 700 °C for 3 minutes. The transverse rupture strength (TRS of the segments was assessed using a three-point bending test. Ankara andesite stone was cut to examine the wear behavior of segments with boron carbide. Microstructure, surfaces of wear and fracture of segments were determined by scanning electron microscopy (SEM-EDS, and X-ray diffraction (XRD analysis. As a result, the wear rate decreased significantly in the 0-5 wt.% B4C contents, while it increased in the 5-10 wt.% B4C contents. With increase in sintering temperature, the wear rate decreased due to the hard matrix.

  17. Preparation, characterization and wear behavior of carbon coated magnesium alloy with electroless plating nickel interlayer

    International Nuclear Information System (INIS)

    Mao, Yan; Li, Zhuguo; Feng, Kai; Guo, Xingwu; Zhou, Zhifeng; Dong, Jie; Wu, Yixiong

    2015-01-01

    Highlights: • The carbon film with nickel interlayer (Ni + C coating) is deposited on GW83. • In Ni + C composite coating the carbon coating has good adhesion with the nickel interlayer. • The wear track of Ni + C coating is narrower compared to the bare one. • The wear resistance of GW83 is greatly improved by the Ni + C coating. - Abstract: Poor wear resistance of rare earth magnesium alloys has prevented them from wider application. In this study, composite coating (PVD carbon coating deposited on electroless plating nickel interlayer) is prepared to protect GW83 magnesium alloys against wear. The Ni + C composite coating has a dense microstructure, improved adhesion strength and hardness due to the effective support of Ni interlayer. The wear test result shows that the Ni + C composite coating can greatly prolong the wear life of the magnesium alloy. The wear track of the Ni + C coated magnesium alloy is obviously narrower and shows less abrasive particles as compared with the bare one. Abrasive wear is the wear mechanism of the coatings at the room temperature. In conclusion, the wear resistance of the GW83 magnesium alloy can be greatly improved by the Ni + C composite coating

  18. Irreversible mean-field model of the critical behavior of charge-density waves below the threshold for sliding

    Science.gov (United States)

    Sornette, Didier

    1993-05-01

    A mean-field (MF) model of the critical behavior of charge-density waves below the threshold for sliding is proposed, which replaces the combined effect of the pinning force and of the forces exerted by the neighbors on a given particle n by an effective force threshold Xn. It allows one to rationalize the numerical results of Middleton and Fisher [Phys. Rev. Lett. 66 (1991) 92] on the divergence of the polarization and of the largest correlation length and of Pla and Nori [Phys. Rev. Lett. 67 (1991) 919] on the distribution D( d) of sliding bursts of size d, measured in narrow intervals of driving fields E at a finite distance below the threshold Ec.

  19. Laser cladding of nickel base alloy on SS316L for improved wear and corrosion behaviour

    International Nuclear Information System (INIS)

    Awasthi, Reena; Kushwaha, R.P.; Chandra, Kamlesh; Viswanadham, C.S.; Srivastava, D.; Dey, G.K.; Limaye, P.K.

    2013-01-01

    Laser cladding by an Nd:YAG laser was employed to deposit Ni base alloy (Ni-Mo-Cr-Si) on stainless steel-316 L substrate. The resulting defect-free clad with minimum dilution of the substrate was characterized by optical microscopy, scanning electron microscopy, X-ray diffraction and Vickers microhardness test. Dry sliding wear of the cladding and the substrate was evaluated using a ball-on-plate reciprocating wear tester against different counter bodies (WC and 52100 Cr steel). The reciprocating sliding wear resistance of the coating was evaluated as a function of the normal load, keeping the sliding amplitude and sliding speed constant. Wear mechanisms were analyzed by observation of wear track morphology using SEM-EDS. The electrochemical corrosion behavior of clad layer was studied in reducing environment (HCl) to estimate the general corrosion resistance of the laser clad layer in comparison with the substrate SS-316L. The clad layer showed higher wear resistance under reducing condition than that of the substrate material stainless steel 316L. (author)

  20. Two feasible approaches to enhance the wear behaviors of NiCrBSi coating in atmosphere and aqueous environments

    Science.gov (United States)

    Ye, Yuwei; Wang, Chunting; Zheng, Wenru; Xiong, Wei; Wang, Yongxin; Li, Xiaogang

    2017-09-01

    NiCrBSi coating was deposited successfully on the surface of 316 stainless steel substrate by means of plasma spraying. The microstructures and mechanical property were analyzed by scanning electron microscopy, x-ray diffraction, and a Vickers hardness tester. The wear performances of the coatings sliding against the GCr15 ball under ambient air and water conditions were investigated, and two feasible approaches (tungsten carbide (WC)-doping and heat treatment) were used to improve the tribological performance. Results showed that the hardness of the NiCrBSi coating increased by 12.5% and 28.5% and the porosity decreased by 26.1% and 47.8%, respectively, after WC-doping and heat treatment. During dry friction, the friction coefficient and wear rate of the NiCrBSi coating were about 0.47 and 1.4  ×  10-5 mm3 N-1 m-1, respectively. These values were higher than those obtained on other coatings. In water conditions, all coatings showed a lower friction and wear rate than that in ambient air, which was as a result of the lubrication effect of water. Significantly, with WC-doping and heat treatment, the friction coefficients of both coatings were about 18.5% and 36.7%, respectively, lower than that of the NiCrBSi coating. Furthermore, the wear rates of both coatings were about 20% and 70%, respectively, lower than that of the NiCrBSi coating.

  1. Effect of deep cryogenic treatment on the formation of nano-sized carbides and the wear behavior of D2 tool steel

    Science.gov (United States)

    Amini, Kamran; Akhbarizadeh, Amin; Javadpour, Sirus

    2012-09-01

    The effect of deep cryogenic treatment on the microstructure, hardness, and wear behavior of D2 tool steel was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), hardness test, pin-on-disk wear test, and the reciprocating pin-on-flat wear test. The results show that deep cryogenic treatment eliminates retained austenite, makes a better carbide distribution, and increases the carbide content. Furthermore, some new nano-sized carbides form during the deep cryogenic treatment, thereby increasing the hardness and improving the wear behavior of the samples.

  2. Abrasive wear of intermetallics

    International Nuclear Information System (INIS)

    Hawk, J.A.; Alman, D.E.; Wilson, R.D.

    1995-01-01

    The US Bureau of Mines is investigating the wear behavior of a variety of advanced materials. Among the many materials under evaluation are intermetallic alloys based on the compounds: Fe 3 Al, Ti 3 Al, TiAl, Al 3 Ti, NiAl and MoSi 2 . The high hardness, high modulus, low density, and superior environmental stability of these compounds make them attractive for wear materials. This paper reports on the abrasive wear of alloys and composites based on the above compounds. The abrasive wear behavior of these alloys and composites are compared to other engineering materials used in wear applications

  3. Effect of load and reciprocating velocity on the transition from mild to severe wear behavior of Al-Si-SiCp composites in reciprocating conditions

    International Nuclear Information System (INIS)

    Rajeev, V.R.; Dwivedi, D.K.; Jain, S.C.

    2010-01-01

    In the present paper, the effect of normal load and reciprocating velocity on transition from mild to severe wear of A319/15%SiC p , A336/15%SiC p , and A390/15%SiC p composites have been reported. Composites were produced through liquid metal metallurgy route. Adhesive wear behavior of composites was studied under dry reciprocating conditions using indigenously developed reciprocating friction wear test rig conforming to ASTM Standard G133-05. It was found that increase in normal load increases wear rate and depending upon the reciprocating velocity and type of composites, mode of wear changes from mild oxidative to severe metallic wear was noticed. The load corresponding to the transition from mild to severe wear usually termed as transition load was found to decrease with increase in reciprocating velocity and reduction in silicon content in the alloys used for the development of Al-Si-SiC p composites. At 1 m/s reciprocating velocity, the transition load for A319/15%SiC p , A336/15%SiC p and A390/15%SiC p composites were found to be in the range of 60-90 N, 60-105 N and 60-120 N respectively. Scanning electron microscope (SEM) study of wear surface and wear debris were conducted to analyze the mode of wear and operating wear mechanism. Severe wear was characterized by massive plastic deformation and gross material removal while the mild wear was found to be associated with delamination and scoring as main wear mechanisms responsible for material loss. Wear mechanism maps for different Al-(6-18)%Si-15%SiC p composites were proposed in reciprocating contacts.

  4. Ultrastrong Carbon Thin Films from Diamond to Graphene under Extreme Conditions: Probing Atomic Scale Interfacial Mechanisms to Achieve Ultralow Friction and Wear

    Science.gov (United States)

    2016-12-08

    tribological behavior of hard carbon materials during initial sliding contact, in order to understand what controls and enables the transition from high to...publication. Our goal is to characterize and understand the atomic-scale mechanisms governing the tribological behavior (friction and wear) of hard carbon...affecting the sliding behavior of these materials, including: rehybridization from sp3 to sp2-bonding of the C atoms20, formation of bonds across the

  5. Effect of cobalt content on wear and corrosion behaviors of electrodeposited Ni-Co/WC nano-composite coatings.

    Science.gov (United States)

    Amadeh, A; Ebadpour, R

    2013-02-01

    Metal-ceramic composite coatings are widely used in automotive and aerospace industries as well as micro-electronic systems. Electrodeposition is an economic method for application of these coatings. In this research, nickel-cobalt coatings reinforced by nano WC particles were applied on carbon steel substrate by pulse electrodeposition from modified Watts bath containing different amounts of cobalt sulphate as an additive. Saccharin and sodium dodecyl sulphate (SDS) were also added to electroplating bath as grain refiner and surfactant, respectively. The effect of cobalt content on wear and corrosion behavior of the coatings was investigated. Wear and corrosion properties were assessed by pin-on-disk and potentiodynamic polarization methods, respectively. Phase analysis was performed by X-ray diffraction (XRD) using CuK(alpha) radiation and the worn surfaces were studied by means of Scanning Electron Microscopy (SEM). The results showed that the addition of cobalt improved the wear resistance of the coatings. In the presence of 18 g/L cobalt in electrodeposition bath, the wear rate of the coating decreased to 0.002 mg/m and the coefficient of friction reduced to 0.695 while they were 0.004 mg/m and 0.77 in the absence of cobalt, respectively. This improvement in wear properties can be attributed to the formation of hcp phase in metallic matrix. Meanwhile, the corrosion resistance of the coatings slightly reduced because cobalt is more active metal with respect to nickel.

  6. Effect of nanoparticles as lubricant additives on friction and wear behavior of tetrahedral amorphous carbon (ta-C coating

    Directory of Open Access Journals (Sweden)

    Xiang Li

    2018-03-01

    Full Text Available As diamond like carbon (DLC coating becomes increasingly popular in providing low friction and wear under lubricated conditions, the effect of various oil additives on tribological behavior of DLC coating is drawing more attention. Various oil additives, such as ZnDTP and MoDTC, have been widely used in automobile engine industry to pursuit excellent tribological performance in the insufficient lubrication condition. Although such commercial oil additives have been proven to reduce friction or/and wear to some extent, usage of such high -SAPS (sulphuric ash, phosphor, sulfphur conventional additives is bound to arouse concerns due to environmental reasons. In this research, we investigate the effect of two nanoparticle oil additives, which are cerium oxide (CeO2 and zirconium dioxide (ZrO2, on friction and wear of non-hydrogen tetrahedral amorphous carbon (ta-C coating. The results show that by adding ZrO2 nanoparticle, the friction of DLC coating could be reduced about 32% compared to non-additive base oil scenario, but specific wear rate increases by 40%. When CeO2 nanoparticle is used, friction increases by 22% compared to non-additive base oil scenario, however wear decreases by nearly 77%.

  7. Combating Wear of ASTM A36 Steel by Surface Modification Using Thermally Sprayed Cermet Coatings

    Directory of Open Access Journals (Sweden)

    Vineet Shibe

    2016-01-01

    Full Text Available Thermal spray coatings can be applied economically on machine parts to enhance their requisite surface properties like wear, corrosion, erosion resistance, and so forth. Detonation gun (D-Gun thermal spray coatings can be applied on the surface of carbon steels to improve their wear resistance. In the present study, alloy powder cermet coatings WC-12% Co and Cr3C2-25% NiCr have been deposited on ASTM A36 steel with D-Gun thermal spray technique. Sliding wear behavior of uncoated ASTM A36 steel and D-Gun sprayed WC-12% Co and Cr3C2-25% NiCr coatings on base material is observed on a Pin-On-Disc Wear Tester. Sliding wear performance of WC-12% Co coating is found to be better than the Cr3C2-25% NiCr coating. Wear performance of both these cermet coatings is found to be better than uncoated ASTM A36 steel. Thermally sprayed WC-12% Co and Cr3C2-25% NiCr cermet coatings using D-Gun thermal spray technique is found to be very useful in improving the sliding wear resistance of ASTM A36 steel.

  8. Abrasive wear behavior of heat-treated ABC-silicon carbide

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiao Feng; Lee, Gun Y.; Chen, Da; Ritchie, Robert O.; De Jonghe, Lutgard C.

    2002-06-17

    Hot-pressed silicon carbide, containing aluminum, boron, and carbon additives (ABC-SiC), was subjected to three-body and two-body wear testing using diamond abrasives over a range of sizes. In general, the wear resistance of ABC-SiC, with suitable heat treatment, was superior to that of commercial SiC.

  9. Wear Behavior of Selected Nuclear Grade Graphites at Room Temperature in Ambient Air Environment

    International Nuclear Information System (INIS)

    Kim, Eung-Seon; Park, Kwang-Seok; Kim, Yong-Wan

    2008-01-01

    In a very high temperature reactor (VHTR), graphite will be used not only for as a moderator and reflector but also as a major structural component due to its excellent neutronic, thermal and mechanical properties. In the VHTR, wear of graphite components is inevitable due to a neutron irradiation-induced dimensional change, thermal gradient, relative motions of graphite components and a shock load such as an earthquake. Large wear particles accumulated at the bottom of a reactor can influence the cooling of the lower part and small wear particles accumulated on the primary circuit and heat exchanger tube can make it difficult to inspect the equipment, and also decrease the heat exchange rate. In the present work, preliminary wear tests were performed at room temperature in ambient air environment to understand the basic wear characteristics of selected nuclear grade graphites for the VHTR

  10. Slide 1

    Indian Academy of Sciences (India)

    Projected Rainfall (Weighted Mean CDF; A1B scenario) · Slide 18 · Imprecise Probability · Bounds for Probability of Drought · Slide 21 · Possibility Distribution of GCMs and Scenarios · Mahanadi River Basin - Streamflow · Projections for future monsoon inflows to Hirakud Reservoir · Slide 25 · Rule curve for adaptive policies.

  11. Tribological Behavior of Babbitt Alloy Rubbing Against Si3N4 and Steel Under Dry Friction Condition

    Science.gov (United States)

    Ji, Xianbing; Chen, Yinxia

    2016-03-01

    The tribological behavior of Babbitt alloy rubbing with Si3N4 ball and steel ball with various sliding speeds at dry friction condition was investigated. It was found that B88 alloy rubbing with Si3N4 ball and steel ball possesses a low sliding wear resistance at dry friction. The wear rate is above 10-4 mm3/Nm, and the friction coefficient is from 0.2 to 0.4. At low sliding speed of 0.05-0.1 m/s, the mainly wear mechanisms are microgroove and fatigue wear, while at high sliding speed of 0.5 m/s, the wear mechanisms depend on plastic deformation and delamination. The high wear rate indicates that it is needed to prevent Babbitt alloy from working at dry friction conditions, while the low friction coefficient suggests that it is not easy to the occurrence of cold weld.

  12. Effects of applying an external magnetic field during the deep cryogenic heat treatment on the corrosion resistance and wear behavior of 1.2080 tool steel

    International Nuclear Information System (INIS)

    Akhbarizadeh, Amin; Amini, Kamran; Javadpour, Sirus

    2012-01-01

    Highlights: ► Deep cryogenic increases the carbide percentage and make a more homogenous distribution. ► Deep cryogenic improve the wear resistance and corrosion behavior of 1.2080 tool steel. ► Applying the magnetic field weaker the carbide distribution and decreases the carbides percentage. ► Magnetized samples showed weaker corrosion and wear behavior. -- Abstract: This work concerns with the effect of applying an external magnetic field on the corrosion behavior, wear resistance and microstructure of 1.2080 (D2) tool steel during the deep cryogenic heat treatment. These analyses were performed via scanning electron microscope (SEM), optical microscope (OM), transmission electron microscope (TEM) and X-ay diffraction (XRD) to study the microstructure, a pin-on-disk wear testing machine to study the wear behavior, and linear sweep voltammetry to study the corrosion behavior of the samples. It was shown that the deep cryogenic heat treatment eliminates retained austenite and makes a more uniform carbide distribution with higher percentage. It was also observed that the deep cryogenic heat treatment improves the wear behavior and corrosion resistance of 1.2080 tool steel. In comparison between the magnetized and non-magnetized samples, the carbide percentage decreases and the carbide distribution weakened in the magnetized samples; subsequently, the wear behavior and corrosion resistance attenuated compared in the magnetized samples.

  13. Synergism of carbon fiber and polyimide in polytetrafluoroethylene-based composites: Friction and wear behavior under sea water lubrication

    International Nuclear Information System (INIS)

    Chen, Beibei; Wang, Jianzhang; Yan, Fengyuan

    2012-01-01

    Highlights: ► The effect of PI and CF on the microstructure of PTFE was investigated. ► PI and CF had synergism on the improvement of tribological property of PTFE. ► PTFE-4 (with 5% PI and 15% CF) showed promising application in ocean environment. -- Abstract: Polytetrafluoroethylene-based (PTFE-based) composites reinforced simultaneously with carbon fiber (CF) and polyimide (PI) of different volume fractions were prepared. The microstructure and phase composition of as-prepared PTFE-based composites were analyzed by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). Besides, their friction and wear behavior under sea water lubrication was evaluated in relation to the synergistic effect between CF and PI using a ring-on-block test rig, and their worn surfaces were also analyzed using SEM. Results showed that the incorporation of PI induced loosening of the microstructure of PTFE but increased the wear resistance. Contrary to the above, the incorporation of CF led to increased compactness of PTFE, and the compactness as well as wear resistance of the PTFE-based composites increased with the increase of CF content. More importantly, the simultaneous incorporation of PI and CF at a proper volume fraction led to drastically reduced wear rate of PTFE under sea water lubrication. This implies that there exists synergistic friction-reducing and wear-resistant effect between PI and CF. As a result, the PTFE-based composite containing 5% PI (volume fraction) and 15% CF had the best wear resistance, showing promising application in ocean environment.

  14. Wear behavior of AA 5083/SiC nano-particle metal matrix composite: Statistical analysis

    Science.gov (United States)

    Hussain Idrisi, Amir; Ismail Mourad, Abdel-Hamid; Thekkuden, Dinu Thomas; Christy, John Victor

    2018-03-01

    This paper reports study on statistical analysis of the wear characteristics of AA5083/SiC nanocomposite. The aluminum matrix composites with different wt % (0%, 1% and 2%) of SiC nanoparticles were fabricated by using stir casting route. The developed composites were used in the manufacturing of spur gears on which the study was conducted. A specially designed test rig was used in testing the wear performance of the gears. The wear was investigated under different conditions of applied load (10N, 20N, and 30N) and operation time (30 mins, 60 mins, 90 mins, and 120mins). The analysis carried out at room temperature under constant speed of 1450 rpm. The wear parameters were optimized by using Taguchi’s method. During this statistical approach, L27 Orthogonal array was selected for the analysis of output. Furthermore, analysis of variance (ANOVA) was used to investigate the influence of applied load, operation time and SiC wt. % on wear behaviour. The wear resistance was analyzed by selecting “smaller is better” characteristics as the objective of the model. From this research, it is observed that experiment time and SiC wt % have the most significant effect on the wear performance followed by the applied load.

  15. A Comparative Study on Wear Properties of As Cast, Cast Aged and Forge Aged A356 Alloy with Addition of Grain Refiner and/or Modifier

    Directory of Open Access Journals (Sweden)

    D.G. Mallapur

    2015-03-01

    Full Text Available In the present work, a comparative wear behavior study of three categories of materials viz, as cast, cast aged (casting followed by T6 and forge aged (forging followed by T6 has been investigated. Neither melt treatment nor solid state processing (like aging and forging seems to be altering the wear behavior of the materials drastically. Cast aged A356 materials exhibit higher wear resistance compared to as cast and forge aged A356 materials. Further, it was observed that cast aged samples register lower coefficient of friction compared to other samples. It is also noted that the difference in wear behavior is revealed only at conditions of higher load, higher speed and longer sliding distance of testing. At lower regimes the difference is marginal. Among cast aged samples, ones treated with combined addition exhibit better wear resistance compared to other materials. Samples treated with combined addition register lowest coefficient of friction followed by samples treated with Sr, those with B, those with Ti and untreated ones. Abrasive wear mechanism is found to be operative in the regime of higher loading and higher velocity of sliding. Adhesive wear mechanism seems to be dominating the wear process at the lower regime of load and velocity of sliding.

  16. Influence of pulsed plasma streams processing on wear behavior of steels in different friction conditions

    International Nuclear Information System (INIS)

    Bandura, A.N.; Byrka, O.V.; Tereshin, V.I.; Bovda, A.M.; Tortika, A.S.

    2000-01-01

    Pulsed plasma streams processing was applied for surface modification of industrial steel samples. Different types of wear tests (pin-on-disk,flat-on-flat, abrasive,cavitation) were carried out for samples irradiated by pulsed nitrogen plasma streams. There was achieved essential decrease of wear and tear of processed surfaces of all kinds of steels including previously thermally quenched ones. Obtained results are of importance for both determination of optimal regimes of plasma streams processing and the most resulting use of pulsed plasma streams for technology purpose, i.e. for identification of wear modes and optimal friction conditions for steels processed by plasma streams

  17. Combating Wear of ASTM A36 Steel by Surface Modification Using Thermally Sprayed Cermet Coatings

    OpenAIRE

    Shibe, Vineet; Chawla, Vikas

    2016-01-01

    Thermal spray coatings can be applied economically on machine parts to enhance their requisite surface properties like wear, corrosion, erosion resistance, and so forth. Detonation gun (D-Gun) thermal spray coatings can be applied on the surface of carbon steels to improve their wear resistance. In the present study, alloy powder cermet coatings WC-12% Co and Cr3C2-25% NiCr have been deposited on ASTM A36 steel with D-Gun thermal spray technique. Sliding wear behavior of uncoated ASTM A36 ste...

  18. Effect of oxidation on the wear behavior of a ZrN coating

    Energy Technology Data Exchange (ETDEWEB)

    Atar, E. [Gebze Inst. of Tech., Material Science and Engineering Dept., Kocaeli (Turkey); Cimenoglu, H.; Kayali, E.S. [Istanbul Technical Univ., Dept. of Metallurgy and Materials Engineering, Azazaga, Istanbul (Turkey)

    2005-07-01

    In the present study tribological performance of ZrN coatings deposited on hardened AISI D2 quality cold work tool steel by arc-physical vapor deposition technique has been examined in as-deposited and oxidized conditions. ZrN coatings were oxidized at 400 C for various times up to 12 h. Reciprocating wear tests carried out by rubbing Al{sub 2}O{sub 3} balls on the coatings, revealed significant improvement in wear resistance of ZrN coating upon oxidation. Oxidation treatment at 400 C for 12 h yielded seven times higher wear resistance than as-deposited ZrN coating, beside significant reduction in the wear of counterface (Al{sub 2}O{sub 3} ball). (orig.)

  19. Effect of oxidation on the wear behavior of a ZrN coating

    International Nuclear Information System (INIS)

    Atar, E.; Cimenoglu, H.; Kayali, E.S.

    2005-01-01

    In the present study tribological performance of ZrN coatings deposited on hardened AISI D2 quality cold work tool steel by arc-physical vapor deposition technique has been examined in as-deposited and oxidized conditions. ZrN coatings were oxidized at 400 C for various times up to 12 h. Reciprocating wear tests carried out by rubbing Al 2 O 3 balls on the coatings, revealed significant improvement in wear resistance of ZrN coating upon oxidation. Oxidation treatment at 400 C for 12 h yielded seven times higher wear resistance than as-deposited ZrN coating, beside significant reduction in the wear of counterface (Al 2 O 3 ball). (orig.)

  20. Quantifying Cutting and Wearing Behaviors of TiN- and CrNCoated AISI 1070 Steel

    Directory of Open Access Journals (Sweden)

    Ahmet Cakan

    2008-11-01

    Full Text Available Hard coatings such as titanium nitride (TiN and chromium nitride (CrN are widely used in cutting and forming tools against wear and corrosion. In the present study, hard coating films were deposited onto AISI 1070 steels by a cathodic arc evaporation plating (CAVP technique. These samples were subjected to wear in a conventional lathe for investigating the tribological behaviour of coating structure, and prenitrided subsurface composition was characterized using scanning electron microscopy (SEM, line scan analyses and X-ray diffraction (XRD. The wear properties of TiN- and CrNcoated samples were determined using an on-line monitoring system. The results show that TiN-coated samples demonstrate higher wear resistance than CrN-coated samples.

  1. Influence of Coating with Some Natural Based Materials on the Erosion Wear Behavior of Glass Fiber Reinforced Epoxy Resin

    OpenAIRE

    Aseel Basim Abdul Hussein; Emad Saadi AL-Hassani; Reem Alaa Mohamed

    2015-01-01

    In the present study, composites were prepared by Hand lay-up molding. The composites constituents were epoxy resin as a matrix, 6% volume fractions of glass fibers (G.F) as reinforcement and 3%, 6% volume fractions of preparation natural material (Rice Husk Ash, Carrot Powder, and Sawdust) as filler. Studied the erosion wear behavior and coating by natural wastes (Rice Husk Ash) with epoxy resin after erosion. The results showed the non – reinforced epoxy have lower resistance erosion than n...

  2. Ultra-high wear resistance of ultra-nanocrystalline diamond film: Correlation with microstructure and morphology

    Science.gov (United States)

    Rani, R.; Kumar, N.; Lin, I.-Nan

    2016-05-01

    Nanostructured diamond films are having numerous unique properties including superior tribological behavior which is promising for enhancing energy efficiency and life time of the sliding devices. High wear resistance is the principal criterion for the smooth functioning of any sliding device. Such properties are achievable by tailoring the grain size and grain boundary volume fraction in nanodiamond film. Ultra-nanocrystalline diamond (UNCD) film was attainable using optimized gas plasma condition in a microwave plasma enhanced chemical vapor deposition (MPECVD) system. Crystalline phase of ultra-nanodiamond grains with matrix phase of amorphous carbon and short range ordered graphite are encapsulated in nanowire shaped morphology. Film showed ultra-high wear resistance and frictional stability in micro-tribological contact conditions. The negligible wear of film at the beginning of the tribological contact was later transformed into the wearless regime for prolonged sliding cycles. Both surface roughness and high contact stress were the main reasons of wear at the beginning of sliding cycles. However, the interface gets smoothened due to continuous sliding, finally leaded to the wearless regime.

  3. Effect of Wearing a Telemetry Jacket on Behavioral and Physiologic Parameters of Dogs in the Open-Field Test.

    Science.gov (United States)

    Fish, Richard E; Foster, Melanie L; Gruen, Margaret E; Sherman, Barbara L; Dorman, Davidc C

    2017-07-01

    Safety pharmacology studies in dogs often integrate behavioral assessments made using video recording with physiologic measurements collected by telemetry. However, whether merely wearing the telemetry vest affects canine behavior and other parameters has not been evaluated. This pilot study assessed the effect of a telemetry vest on behavioral and physiologic responses to an environmental stressor, the sounds of a thunderstorm, in Labrador retrievers. Dogs were assigned to one of 2 experimental groups (Vest and No-Vest, n = 8 dogs per group) by using a matched pairs design, with a previously determined, sound-associated anxiety score as the blocking variable. Dogs were individually retested with the same standardized sound stimulus (thunderstorm) in an open-field arena, and their behavioral responses were video recorded. Video analysis of locomotor activity and anxiety-related behavior and manual determination of heart rate and body temperature were performed; results were compared between groups. Vest wearing did not affect total locomotor activity or rectal body temperature but significantly decreased heart rate by 8% and overall mean anxiety score by 34% during open-field test sessions. Our results suggest that the use of telemetry vests in dogs influences the measurement of physiologic parameters and behaviors that are assessed in safety pharmacology studies.

  4. Estimation of Wear Behavior of Polyphenylene Sulphide Composites Reinforced with Glass/Carbon Fibers, Graphite and Polytetrafluoroethylene, by Pin-on-disc Test

    Directory of Open Access Journals (Sweden)

    M.A.C. Besnea

    2015-03-01

    Full Text Available Wear behavior of polyphenylene sulphide composites was investigated according to load and test speed. Two types of materials were studied: first, with 40 wt% glass fiber, and second, with 10 wt% carbon fiber, 10 wt% graphite and 10 wt%. Tribological tests were performed on the universal tribometer UMT-2, using a pin-on-disc device. The friction coefficient and wear rate for the composites were analyzed. As a result of experimental tests, it was established that polymer composite with polyphenylene sulphide matrix, carbon fibers, graphite and polytetrafluorethylene exhibit good wear behavior under operating conditions.

  5. Microstructure and wear behavior of {gamma}/Al{sub 4}C{sub 3}/TiC/CaF{sub 2} composite coating on {gamma}-TiAl intermetallic alloy prepared by Nd:YAG laser cladding

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiubo [School of Mechanical and Electronic Engineering, 178 Ganjiang East Road, Soochow University, Suzhou 215021 (China)], E-mail: liubobo0828@yahoo.com.cn; Shi Shihong [School of Mechanical and Electronic Engineering, 178 Ganjiang East Road, Soochow University, Suzhou 215021 (China); Guo Jian [School of Materials and Chemical Engineering, Zhongyuan Institute of Technology, 41 Zhongyuan West Road, Zhengzhou 450007 (China); Fu Geyan; Wang Mingdi [School of Mechanical and Electronic Engineering, 178 Ganjiang East Road, Soochow University, Suzhou 215021 (China)

    2009-03-15

    As a further step in obtaining high performance elevated temperature self-lubrication anti-wear composite coatings on TiAl alloy, a novel Ni-P electroless plating method was adopted to encapsulate the as-received CaF{sub 2} in the preparation of precursor NiCr-Cr{sub 3}C{sub 2}-CaF{sub 2} mixed powders with an aim to decrease its mass loss and increase its compatibility with the metal matrix during a Nd:YAG laser cladding. The microstructure of the coating was examined using X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) and the friction and wear behavior of the composite coatings sliding against the hardened 0.45% C steel ring was evaluated using a block-on-ring wear tester at room temperature. It was found that the coating had a unique microstructure consisting of primary dendrites TiC and block Al{sub 4}C{sub 3} carbides reinforcement as well as fine isolated spherical CaF{sub 2} solid lubrication particles uniformly dispersed in the NiCrAlTi ({gamma}) matrix. The good friction-reducing and anti-wear abilities of the laser clad composite coating was suggested to the Ni-P electroless plating and the attendant reduction of mass loss of CaF{sub 2} and the increasing of it's wettability with the NiCrAlTi ({gamma}) matrix during the laser cladding process.

  6. Fretting wear behavior of zirconium alloy in B-Li water at 300 °C

    Science.gov (United States)

    Zhang, Lefu; Lai, Ping; Liu, Qingdong; Zeng, Qifeng; Lu, Junqiang; Guo, Xianglong

    2018-02-01

    The tangential fretting wear of three kinds of zirconium alloys tube mated with 304 stainless steel (SS) plate was investigated. The tests were conducted in an autoclave containing 300 °C pressurized B-Li water for tube-on-plate contact configuration. The worn surfaces were examined with scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and 3D microscopy. The cross-section of wear scar was examined with transmission electron microscope (TEM). The results indicated that the dominant wear mechanism of zirconium alloys in this test condition was delamination and oxidation. The oxide layer on the fretted area consists of outer oxide layer composed of iron oxide and zirconium oxide and inner oxide layer composed of zirconium oxide.

  7. Modeling of wear behavior of Al/B_4C composites produced by powder metallurgy

    International Nuclear Information System (INIS)

    Sahin, Ismail; Bektas, Asli; Guel, Ferhat; Cinci, Hanifi

    2017-01-01

    Wear characteristics of composites, Al matrix reinforced with B_4C particles percentages of 5, 10,15 and 20 produced by the powder metallurgy method were studied in this study. For this purpose, a mixture of Al and B_4C powders were pressed under 650 MPa pressure and then sintered at 635 C. The analysis of hardness, density and microstructure was performed. The produced samples were worn using a pin-on-disk abrasion device under 10, 20 and 30 N load through 500, 800 and 1200 mesh SiC abrasive papers. The obtained wear values were implemented in an artificial neural network (ANN) model having three inputs and one output using feed forward backpropagation Levenberg-Marquardt algorithm. Thus, the optimum wear conditions and hardness values were determined.

  8. Modeling of wear behavior of Al/B{sub 4}C composites produced by powder metallurgy

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, Ismail; Bektas, Asli [Gazi Univ., Ankara (Turkey). Dept. of Industrial Design Engineering; Guel, Ferhat; Cinci, Hanifi [Gazi Univ., Ankara (Turkey). Dept. of Materials and Metallurgy Engineering

    2017-06-01

    Wear characteristics of composites, Al matrix reinforced with B{sub 4}C particles percentages of 5, 10,15 and 20 produced by the powder metallurgy method were studied in this study. For this purpose, a mixture of Al and B{sub 4}C powders were pressed under 650 MPa pressure and then sintered at 635 C. The analysis of hardness, density and microstructure was performed. The produced samples were worn using a pin-on-disk abrasion device under 10, 20 and 30 N load through 500, 800 and 1200 mesh SiC abrasive papers. The obtained wear values were implemented in an artificial neural network (ANN) model having three inputs and one output using feed forward backpropagation Levenberg-Marquardt algorithm. Thus, the optimum wear conditions and hardness values were determined.

  9. Wear Process Analysis of the Polytetrafluoroethylene/Kevlar Twill Fabric Based on the Components’ Distribution Characteristics

    Directory of Open Access Journals (Sweden)

    Gu Dapeng

    2017-12-01

    Full Text Available Polytetrafluoroethylene (PTFE/Kevlar fabric or fabric composites with excellent tribological properties have been considered as important materials used in bearings and bushing, for years. The components’ (PTFE, Kevlar, and the gap between PTFE and Kevlar distribution of the PTFE/Kevlar fabric is uneven due to the textile structure controlling the wear process and behavior. The components’ area ratio on the worn surface varying with the wear depth was analyzed not only by the wear experiment, but also by the theoretical calculations with our previous wear geometry model. The wear process and behavior of the PTFE/Kevlar twill fabric were investigated under dry sliding conditions against AISI 1045 steel by using a ring-on-plate tribometer. The morphologies of the worn surface were observed by the confocal laser scanning microscopy (CLSM. The wear process of the PTFE/Kevlar twill fabric was divided into five layers according to the distribution characteristics of Kevlar. It showed that the friction coefficients and wear rates changed with the wear depth, the order of the antiwear performance of the previous three layers was Layer III>Layer II>Layer I due to the area ratio variation of PTFE and Kevlar with the wear depth.

  10. Slide 1

    Indian Academy of Sciences (India)

    Game Theory · Strategic Form Games (Normal Form Games) · Example : Prisoner's Dilemma · Dominant Strategy Equilibrium · Nash Equilibrium · Nash's Theorem · Slide 17 · Slide 18 · Example 1: Mechanism Design Fair Division of a Cake · Example 2: Mechanism Design Truth Elicitation through an Indirect Mechanism.

  11. The Effects of Rare Earth Pr and Heat Treatment on the Wear Properties of AZ91 Alloy

    Directory of Open Access Journals (Sweden)

    Ning Li

    2018-06-01

    Full Text Available This paper investigated the influences of Pr addition and heat treatment (T6 on the dry sliding wear behavior of AZ91 alloy. The wear rates and friction coefficients were measured by using a pin-on-disc tribometer under loads of 30, 60 and 90 N at dry sliding speeds of 100 rpm, over a sliding time of 15 min. The worn surfaces were examined using a scanning electron microscope and was analyzed with an energy dispersive spectrometer. The experimental results revealed that AZ91-1.0%Pr magnesium alloy exhibited lower wear rate and friction coefficient than the other investigated alloys. As the applied load increased, the wear rate and friction coefficient increased. Compared with the as-cast AZ91-1.0%Pr magnesium alloy, the hardness and wear resistance of the alloy after solution treatment were reduced, and through the subsequent aging, the hardness and wear resistance of the alloy were improved and the hardness was 101.1 HB (compared to as-cast AZ91 magnesium alloy, it increased by 45%. The AZ91-1.0%Pr with T6 magnesium alloy exhibited best wear resistance. Abrasion was dominant at load of 30 N, delamination was dominant at load of 60 N and plastic deformation was dominant at load of 90 N. Oxidation was observed at all loads.

  12. Tooth wear

    Directory of Open Access Journals (Sweden)

    Tušek Ivan

    2014-01-01

    surfaces. Attrition of teeth (attritio dentium represents teeth wear during mastication, friction on the tooth or teeth during parafunctional mandibular movements (bruxism, but without the abrasive effect. Dental erosion (erosio dentium or corrosive wear is a progressive, irreversible loss of dental hard tissue resulting from the effect of acids and /or chelation in the mouth, but without the participation of bacteria. Acids, of either exogenous or endogenous origin (peptic ulcer, gastritis, or bulimia, anoreksia nervosa, that come into the mouth can lead to different clinical manifestations of erosion depending on the time of exposure, the microstructure of teeth, buffering capacity, the amount of saliva and other factors. The changes are visible on the palatal surfaces of upper anterior teeth and, in severe cases, the lingual surfaces of posterior teeth. Occupational dental erosion occurs during exposure to industrial gases that contain hydrochloric or sulfuric acids, as well as the acids used in galvanizing and manufacture of battery and weapons. Due to the multifactorial nature of erosive tooth wear preventive measures must be applied taking into account chemical and biological factors as well as the patient's behavior associated with the etiology and pathogenesis of erosion. It is recommended to consume food and drinks that stimulate the secretion of large amounts of saliva base; to use neutral or alkaline mouthwash, and to chew sugar-free gum; to apply adequate oral hygiene (soft brushes, non-abrasive tooth paste, proper washing technique and not to consume aciding food and carbonated soft drinks and fizzy drinks in a great amount and frequently. It is necessary to apply preparations with high content of fluoride, and lubricant of tooth wear (powder CaF, CaF mixture and olive oil, and asset-based titanium tetrafluoride and casein-calcium phosphate. Commercial tooth paste that contains CPP-ACP (casein phosphopeptide-amorphous calcium phosphate and calcium phosphate

  13. Wear Calculation for Sliding Friction Pairs

    Directory of Open Access Journals (Sweden)

    Springis G.

    2014-04-01

    Full Text Available ums Mūsdienu ražošanas procesa viens no pamatmērķiem ir produkcijas kvalitātes līmeņa paaugstināšana, tas nozīmē arī dažādu izstrādājumu nepieciešamā kalpošanas laika nodrošināšanu un nodilumizturības palielināšanu. Svarīga loma šī uzdevuma sasniegšanā ir salāgojamo detaļu kalpošanas laika prognozēšanai, kas ir ļoti aktuāls jautājums, jo attīstoties dažādām ražošanas, kā arī mēriekārtu tehnoloģijām, kļūst iespējams arvien precīzāk noteikt nepieciešamos datus, kuri vēlāk tiek izmantoti arī analītiskajos aprēķinos.

  14. Wear Behavior of Uncoated and Coated Tools under Complex Loading Conditions

    Directory of Open Access Journals (Sweden)

    M. Wieland

    2012-03-01

    Full Text Available In automotive industry crash relevant structures of the body in white are manufactured using the direct hot stamping process. Due to the high temperature difference between the hot blank and the cold tool surfaces and the relative movement between the blank and the tool surfaces during the forming operation, high thermal and mechanical loads are applied on the tool leading to excessive wear in terms of adhesion on the tool surfaces. One possibility to reduce wear of hot stamping tools is the application of tool coating systems. In the scope of this work uncoated and coated tools are characterized under complex loading conditions with respect to adhesive layer build-up.

  15. Friction and Wear Behavior of Ti-6Al-7Nb Biomaterial Alloy

    OpenAIRE

    FELLAH , Mamoun; ASSALA , Omar; LABAÏZ , Mohamed; DEKHIL , Leila; IOST , Alain

    2013-01-01

    Titanium and its alloys have been used as implant materials due to their very good mechanical and corrosion resistance and biocompatibility [1,2]. The most used biomaterials were commercially pure titanium (CP-Ti} issued in clinics, although CP- Ti has been pointed out to have disadvantages of low strength, difficulty for polishing, and poor wear resistance. Therefore, Titanium is still insufficient for high-stress applications ; e.g., long spanned fixed prostheses and the fr...

  16. A Study on the Corrosion and Wear Behavior of Electrodeposited Ni-W-P Coating

    Science.gov (United States)

    Lee, Hung Bin; Wu, Meng Yen

    2017-10-01

    In this study, the tribocorrosion of electroplated Ni-W-P alloy coating (3.9 to 4.3 at. pct W and 13.1 to 14.7 at. pct P) on a cylindrical copper substrate was investigated using a block-on-ring tester. The wear and corrosion performance of the coating and their synergic effect were measured at different overpotentials. Under simple immersion corrosion conditions with an increasing overpotential from open-circuit potential to +400 mVSCE, the surface of the coating initially showed no obvious corrosion, eventually developing pitting holes that subsequently enlarged and showing the spreading of cracks. The corrosion products were a mixture of NiO, WO3, and phosphate, and the corroded surface was P-rich, porous, and less crystalline than the pristine coating. Corrosion and mechanical wear had little influence on tribocorrosion at low overpotential values. However, the synergic effect drastically became stronger at high overpotentials. The surface was full of large pitting holes and grooves. The weight loss due to the corrosion component increased linearly with the overpotential but was limited in comparison with the wear component, which was the main cause of weight loss. On the other hand, the friction coefficient first increased and then decreased with an increase in overpotential. Both the surface morphology of the corroded coating and the thickness of the corrosion oxide play important roles in this friction characteristic.

  17. Motor Behavior: From Telegraph Keys and Twins to Linear Slides and Stepping

    Science.gov (United States)

    Thomas, Jerry R.

    2006-01-01

    Motor behavior is a significant area of scholarship with 64 Fellows from the American Academy of Kinesiology and Physical Education engaged in that work since 1930. This paper provides a brief overview of the history of research in motor development and motor control/learning, particularly noting the contributions to scholarship of Academy…

  18. Microstructure and Wear Behavior of Atmospheric Plasma-Sprayed AlCoCrFeNiTi High-Entropy Alloy Coating

    Science.gov (United States)

    Tian, Li-Hui; Xiong, Wei; Liu, Chuan; Lu, Sheng; Fu, Ming

    2016-12-01

    Due to the advantages such as high strength, high hardness and good wear resistance, high-entropy alloys (HEAs) attracted more and more attentions in recent decades. However, most reports on HEAs were limited to bulk materials. Although a few of studies on atmospheric plasma-sprayed (APS) HEA coatings were carried out, the wear behavior, especially the high-temperature wear behavior of those coatings has not been investigated till now. Therefore, in this study, APS was employed to deposit AlCoCrFeNiTi high-entropy alloy coating using mechanically alloyed AlCoCrFeNiTi powder as the feedstock. The phase structure of the initial powder, the feedstock powder and the as-sprayed coating was examined by an x-ray diffractometer. The surface morphology of the feedstock powder and the microstructure of the as-sprayed coating were analyzed by field emission scanning electron microscopy and energy-dispersive spectroscopy. The bonding strength and the microhardness of the as-sprayed coating were tested. The wear behavior of the coating at 25, 500, 700 and 900 °C was investigated by analysis of the wear surface morphology and measurements of the volume wear rate and the coefficient of friction.

  19. Exploring viewing behavior data from whole slide images to predict correctness of students' answers during practical exams in oral pathology.

    Science.gov (United States)

    Walkowski, Slawomir; Lundin, Mikael; Szymas, Janusz; Lundin, Johan

    2015-01-01

    The way of viewing whole slide images (WSI) can be tracked and analyzed. In particular, it can be useful to learn how medical students view WSIs during exams and how their viewing behavior is correlated with correctness of the answers they give. We used software-based view path tracking method that enabled gathering data about viewing behavior of multiple simultaneous WSI users. This approach was implemented and applied during two practical exams in oral pathology in 2012 (88 students) and 2013 (91 students), which were based on questions with attached WSIs. Gathered data were visualized and analyzed in multiple ways. As a part of extended analysis, we tried to use machine learning approaches to predict correctness of students' answers based on how they viewed WSIs. We compared the results of analyses for years 2012 and 2013 - done for a single question, for student groups, and for a set of questions. The overall patterns were generally consistent across these 3 years. Moreover, viewing behavior data appeared to have certain potential for predicting answers' correctness and some outcomes of machine learning approaches were in the right direction. However, general prediction results were not satisfactory in terms of precision and recall. Our work confirmed that the view path tracking method is useful for discovering viewing behavior of students analyzing WSIs. It provided multiple useful insights in this area, and general results of our analyses were consistent across two exams. On the other hand, predicting answers' correctness appeared to be a difficult task - students' answers seem to be often unpredictable.

  20. Exploring viewing behavior data from whole slide images to predict correctness of students′ answers during practical exams in oral pathology

    Directory of Open Access Journals (Sweden)

    Slawomir Walkowski

    2015-01-01

    Full Text Available The way of viewing whole slide images (WSI can be tracked and analyzed. In particular, it can be useful to learn how medical students view WSIs during exams and how their viewing behavior is correlated with correctness of the answers they give. We used software-based view path tracking method that enabled gathering data about viewing behavior of multiple simultaneous WSI users. This approach was implemented and applied during two practical exams in oral pathology in 2012 (88 students and 2013 (91 students, which were based on questions with attached WSIs. Gathered data were visualized and analyzed in multiple ways. As a part of extended analysis, we tried to use machine learning approaches to predict correctness of students′ answers based on how they viewed WSIs. We compared the results of analyses for years 2012 and 2013 - done for a single question, for student groups, and for a set of questions. The overall patterns were generally consistent across these 3 years. Moreover, viewing behavior data appeared to have certain potential for predicting answers′ correctness and some outcomes of machine learning approaches were in the right direction. However, general prediction results were not satisfactory in terms of precision and recall. Our work confirmed that the view path tracking method is useful for discovering viewing behavior of students analyzing WSIs. It provided multiple useful insights in this area, and general results of our analyses were consistent across two exams. On the other hand, predicting answers′ correctness appeared to be a difficult task - students′ answers seem to be often unpredictable.

  1. Wear and corrosion behaviors of Ti6Al4V alloy biomedical materials by silver plasma immersion ion implantation process

    Energy Technology Data Exchange (ETDEWEB)

    Hongxi, Liu [School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Qian, Xu, E-mail: vipliuhx@yahoo.com.cn [Faculty of Adult Education, Kunming University of Science and Technology, Kunming 650051 (China); Xiaowei, Zhang; Chuanqi, Wang [School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Baoyin, Tang [State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001 (China)

    2012-10-30

    In order to improve the wear resistance and anti-corrosion behaviors of Ti6Al4V (TC4) alloy, polished samples were implanted with silver (Ag) ions by plasma immersion ion implantation (PIII) technique. The phase composition and element concentration-depth distribution in modified layer were characterized by X-ray diffraction (XRD) and Auger electron spectrum (AES). Corrosion resistance, microhardness, friction and wear behaviors of PIII-TC4 alloy changed with the Ag ion implantation dose. XRD analysis reveals that the surface modified layer consists of Ag and a small amount of TiAg phases. AES results show that Ag atomic peak concentration is 9.88%, about 14.4 nm from the surface. The maximum nanohardness and elastic modulus of PIII-TC4 alloy increases by 62.5% and 54.5%, respectively. The lowest friction coefficient reduces from 0.78 to 0.2. The test result of potentiodynamic polarization in 3.5% NaCl saturated solution indicates that the sample of Ag ion dose at 1.0 Multiplication-Sign 10{sup 17} ions/cm{sup 2} has the best corrosion resistance with the lowest corrosion current density and the least porosity.

  2. Superlubricity and wearless sliding in diamondlike carbon films

    International Nuclear Information System (INIS)

    Erdemir, A.

    2001-01-01

    Diamondlike carbon (DLC) films have attracted great interest in recent years mainly because of their unusual optical, electrical, mechanical, and tribological properties. Such properties are currently being exploited for a wide range of engineering applications including magnetic hard disks, gears, sliding and roller bearings, scratch resistant glasses, biomedical implants, etc. Systematic studies on carbon-based materials in our laboratory have led to the development of a new class of amorphous DLC films that provide extremely low friction and wear coefficients of 0.001 to 0.005 and 10(sup -11) to 10(sup -10) mm(sup 3) /N.m, respectively, when tested in inert-gas or high-vacuum environments. These films were produced in highly hydrogenated gas discharge plasmas by a plasma enhanced chemical vapor deposition process at room temperature. The carbon source gases used in the deposition of these films included methane, acetylene, and ethylene. Tribological studies in our laboratory have established a very close correlation between the composition of the plasmas and the friction and wear coefficients of the resultant DLC films. Specifically, the friction and wear coefficients of DLC films grown in plasmas with higher hydrogen-to-carbon ratios were much lower than films derived from source gases with lower hydrogen-to-carbon ratios. Fundamental tribological and surface analytical studies have led us to conclude that hydrogen (within the film, as well as on the sliding surfaces) is extremely important for the superlubricity and wearless sliding behavior of these films. Based on these studies, a mechanistic model is proposed to explain the superlow friction and wear properties of the new DLC films

  3. Investigation on corrosion and wear behaviors of nanoparticles reinforced Ni-based composite alloying layer

    International Nuclear Information System (INIS)

    Xu Jiang; Tao Jie; Jiang Shuyun; Xu Zhong

    2008-01-01

    In order to investigate the role of amorphous SiO 2 particles in corrosion and wear resistance of Ni-based metal matrix composite alloying layer, the amorphous nano-SiO 2 particles reinforced Ni-based composite alloying layer has been prepared by double glow plasma alloying on AISI 316L stainless steel surface, where Ni/amorphous nano-SiO 2 was firstly predeposited by brush plating. The composition and microstructure of the nano-SiO 2 particles reinforced Ni-based composite alloying layer were analyzed by using SEM, TEM and XRD. The results indicated that the composite alloying layer consisted of γ-phase and amorphous nano-SiO 2 particles, and under alloying temperature (1000 deg. C) condition, the nano-SiO 2 particles were uniformly distributed in the alloying layer and still kept the amorphous structure. The corrosion resistance of composite alloying layer was investigated by an electrochemical method in 3.5%NaCl solution. Compared with single alloying layer, the amorphous nano-SiO 2 particles slightly decreased the corrosion resistance of the Ni-Cr-Mo-Cu alloying layer. X-ray photoelectron spectroscopy (XPS) revealed that the passive films formed on the composite alloying consisted of Cr 2 O 3 , MoO 3 , SiO 2 and metallic Ni and Mo. The dry wear test results showed that the composite alloying layer had excellent friction-reduced property, and the wear weight loss of composite alloying layer was less than 60% of that of Ni-Cr-Mo-Cu alloying layer

  4. Effect of ion implantation on subsequent erosion and wear behavior of solids

    International Nuclear Information System (INIS)

    McHargue, C.J.

    1985-01-01

    The removal of material from a solid surface by mechanical forces is influenced by material properties (hardness, fracture toughness, yield strength, surface free energy) as well as system parameters (force, velocity of loading, environment). Ion implantation can modify many of the material properties either by directly affecting the deformation characteristics or indirectly by affecting the chemical or phase composition at the surface. The various forms of wear and erosion are analyzed to determine the material and system parameters which control material removal. The effects of implantation on these critical parameters are noted and examples of changes in surface topography under various test conditions are discussed. 18 figs

  5. The Effect of Bias Voltage and Gas Pressure on the Structure, Adhesion and Wear Behavior of Diamond Like Carbon (DLC Coatings With Si Interlayers

    Directory of Open Access Journals (Sweden)

    Liam Ward

    2014-04-01

    Full Text Available In this study diamond like carbon (DLC coatings with Si interlayers were deposited on 316L stainless steel with varying gas pressure and substrate bias voltage using plasma enhanced chemical vapor deposition (PECVD technology. Coating and interlayer thickness values were determined using X-ray photoelectron spectroscopy (XPS which also revealed the presence of a gradient layer at the coating substrate interface. Coatings were evaluated in terms of the hardness, elastic modulus, wear behavior and adhesion. Deposition rate generally increased with increasing bias voltage and increasing gas pressure. At low working gas pressures, hardness and modulus of elasticity increased with increasing bias voltage. Reduced hardness and modulus of elasticity were observed at higher gas pressures. Increased adhesion was generally observed at lower bias voltages and higher gas pressures. All DLC coatings significantly improved the overall wear resistance of the base material. Lower wear rates were observed for coatings deposited with lower bias voltages. For coatings that showed wear tracks considerably deeper than the coating thickness but without spallation, the wear behavior was largely attributed to deformation of both the coating and substrate with some cracks at the wear track edges. This suggests that coatings deposited under certain conditions can exhibit ultra high flexible properties.

  6. Wear behavior of 2-1/4 Cr-1Mo tubing against alloy 718 tube-support material in sodium-cooled steam generators

    International Nuclear Information System (INIS)

    Wilson, W.L.

    1983-05-01

    A series of prototypic steam generator 2-1/4 Cr-1 Mo tube/alloy 718 tube support plate wear tests were conducted in direct support of the Westinghouse Nuclear Components Division -- Breeder Reactor Components Project Large Scale steam Generator design. The initial objective was to verify the acceptable wear behavior of softer, ''over-aged'' alloy 718 support plate material. For all interfaces under all test conditions, resultant wear damage was adhesive in nature with varying amounts of 2-1/4 Cr-1 Mo tube material being adhesively transferred to the alloy 718 tube supports. Maximum tube wear depths exceeded the initially established design allowable limit of 127 μm (.005 in.) at 17 of the 18 interfaces tested. A decrease in contact stresses produced acceptable tube wear depths below a readjusted maximum design allowable value of 381 μm (.015 in.). Additional conservatisms associated with the simulation of a 40-year lifetime of rubbing in a one-week laboratory test provided further confidence that the 381 μm maximum tube wear allowance would not be exceeded in service. Softer, ''over-aged'' alloy 718 material was found to produce slightly less wear damage on 2-1/4 Cr-1 Mo tubing than fully age hardened material. Also, air formed oxide films on the alloy 718 reduced initial tube wear and delayed the onset of adhesive surface damage. However, at high surface stress levels, these films were not sufficiently stable to provide adequate long term protection from adhesive wear. The results of the present work and those of previous test programs suggest that the successful in-sodium tribological performance of 2-1/4 Cr-1 Mo/alloy 718 rubbing couples is dependent upon the presence of lubricative surface films, such as oxides and/or surface reaction or deposition products. 11 refs., 13 figs., 4 tabs

  7. Wear Analysis of a Ti-5Al-3V-2.5Fe Alloy Using a Factorial Design Approach and Fractal Geometry

    Directory of Open Access Journals (Sweden)

    A. W. El-Morsy

    2018-02-01

    Full Text Available This paper describes the application of the full factorial experimental design technique to confirm the significance of the factors affecting the wear behavior of a recycled Ti-5Al-3V-2.5Fe alloy with a minimum number of experiments. The fractal theory has been used to describe the worn surface state and to investigate the relationship between the fractal dimensions and the surface morphology. The experiments of the sliding wear have been performed under stresses in the range of 1-5 MPa and within sliding velocities range of 0.2–2.0 m/s. Morphology of the worn surfaces investigations has been undertaken using a scanning electron microscope. From the analysis of variance and the nonlinear regression model, the results show that the applied stress has a higher contribution to the wear rate than the sliding velocity.

  8. A Comparative Study on the Formation Mechanism of Wear Scars during the Partial and Full Scale Fretting Wear Tests of Spacer Grids

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Ho; Shin, Chang Hwan; Oh, Dong Seok; Kang, Heung Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    Fretting wear studies for evaluating the contact damages of nuclear fuel rods have been focused on the contact shape, rod motion, contact condition, environment, etc.. However, fretting wear mechanism was dramatically changed with slight variation of test variables such as test environments and contact shapes. For example, in an unlubricated condition, effects of wear debris and/or its layer on the fretting wear mechanism showed that the formation of a well-developed layer on the contact surfaces has a beneficial effect for decreasing a friction coefficient. Otherwise, a severe wear was happened due to a third body abrasion. In addition, in water lubrication condition, some of wear debris was remained on worn surface of fuel rod specimens at both sliding and impacting loading conditions. So, it is apparent that a wear rate of fuel rod specimen was easily accelerated by the third-body abrasion. This is because the restrained agglomeration behavior between generated wear particles results in rapid removal of wear debris and its layer. In case of contact shape effects, previous studies show that wear debris are easily trapped between contact surfaces and its debris layer was well developed in a localized area especially in a concave spring rather than a convex spring shape. Consequently, localized wear was happened at both ends of a concave spring and center region of a convex spring. So, it is useful for determining the fretting wear resistance of spacer gird spring and dimple by using part unit in the various lubricated conditions. It is well known that the fretting wear phenomenon of nuclear fuel rod is originated from a flow-induced vibration (FIV) due to the rapid primary coolant. This means that both rod vibration and debris removal behavior were affected by flow fields around the contact regions between fuel rod and spring/dimple. However, all most of the fretting tests were performed by simulating rod vibrating motions such as axial vibration, conservative rod

  9. A Comparative Study on the Formation Mechanism of Wear Scars during the Partial and Full Scale Fretting Wear Tests of Spacer Grids

    International Nuclear Information System (INIS)

    Lee, Young Ho; Shin, Chang Hwan; Oh, Dong Seok; Kang, Heung Seok

    2012-01-01

    Fretting wear studies for evaluating the contact damages of nuclear fuel rods have been focused on the contact shape, rod motion, contact condition, environment, etc.. However, fretting wear mechanism was dramatically changed with slight variation of test variables such as test environments and contact shapes. For example, in an unlubricated condition, effects of wear debris and/or its layer on the fretting wear mechanism showed that the formation of a well-developed layer on the contact surfaces has a beneficial effect for decreasing a friction coefficient. Otherwise, a severe wear was happened due to a third body abrasion. In addition, in water lubrication condition, some of wear debris was remained on worn surface of fuel rod specimens at both sliding and impacting loading conditions. So, it is apparent that a wear rate of fuel rod specimen was easily accelerated by the third-body abrasion. This is because the restrained agglomeration behavior between generated wear particles results in rapid removal of wear debris and its layer. In case of contact shape effects, previous studies show that wear debris are easily trapped between contact surfaces and its debris layer was well developed in a localized area especially in a concave spring rather than a convex spring shape. Consequently, localized wear was happened at both ends of a concave spring and center region of a convex spring. So, it is useful for determining the fretting wear resistance of spacer gird spring and dimple by using part unit in the various lubricated conditions. It is well known that the fretting wear phenomenon of nuclear fuel rod is originated from a flow-induced vibration (FIV) due to the rapid primary coolant. This means that both rod vibration and debris removal behavior were affected by flow fields around the contact regions between fuel rod and spring/dimple. However, all most of the fretting tests were performed by simulating rod vibrating motions such as axial vibration, conservative rod

  10. Effect of Laser Remelting on Friction-Wear Behaviors of Cold Sprayed Al Coatings in 3.5% NaCl Solution

    Directory of Open Access Journals (Sweden)

    Zhang Jing

    2018-02-01

    Full Text Available A cold sprayed Al coating on S355 structural steel was processed using a laser remelting (LR. The surface and cross-section morphologies, chemical compositions, and phases of as-obtained Al coating before and after LR were analyzed using a scanning electronic microscope (SEM, energy dispersive spectrometer (EDS, and X-ray diffractometer (XRD, respectively, and their hardness was measured using a micro-hardness tester. The friction-wear behaviors of Al coating before and after LR in 3.5% NaCl solution were conducted to simulate the sand and gravel scouring on its surface in seawater, the effects of wear loads and speeds on the tribological properties of Al coating were analyzed, and the wear mechanisms under different wear loads and speeds were also discussed. The results show that the Al coating after LR is primarily composed of an Al phase and its hardness is 104.66 HV, increasing 54.70 HV than the cold sprayed Al coating. The average coefficient of friction (COF of cold sprayed Al coating at the wear load of 0.5, 1.0 and 1.5 N is 0.285, 0.239, and 0.435, respectively, while that after LR is 0.243, 0.227, and 0.327, respectively, decreased by 14.73%, 5.02% and 24.83% compared to the cold sprayed Al coating. The wear rate of cold sprayed Al coating at the wear load of 0.5, 1.0 and 1.5 N is 1.60 × 10−4, 2.36 × 10−4, and 2.40 × 10−4 mm3/m·N, respectively, while that after LR is 1.59 × 10−4, 1.70 × 10−4, and 1.94 × 10–4 mm3/m·N, respectively, decreased by 1%, 32%, and 23%, respectively, indicating that LR has high anti-friction performance. Under the wear load action of 1.0 N, the average COF of laser remelted Al coating at the wear speeds of 300, 400 and 500 times/min is 0.294, 0.279, and 0.239, respectively, and the corresponding wear rate is 1.06 × 10−4, 1.24 × 10−4, and 1.70 × 10−4 mm3/m·N, respectively. The wear mechanism of cold sprayed Al coating is primarily corrosion wear at the loads of 0.5 and 1.0 N, and

  11. Influence of thermal oxidation duration on the microstructure and fretting wear behavior of Ti6Al4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Song [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Liao, Zhenhua [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Liu, Yuhong [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Liu, Weiqiang, E-mail: weiqliu@hotmail.com [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China)

    2015-06-01

    Thermal oxidation under water oxidizing atmosphere was performed on Ti6Al4V alloy under different durations from 2 h to 8 h. Surface characterizations were performed using X-ray diffractometery (XRD), scanning electron microscopy (SEM), Raman spectroscopy, nanoindentation and nano scratch testing. Fretting wear behaviors of untreated and oxidized samples were also examined. The formed oxide coating mainly included rutile TiO{sub 2} as well as a little alumina. The weight gain with respect to the oxidation duration obeyed the linear oxidation kinetics law. The growth of oxide grains was in inadequate growth state of incomplete scale coverage from 2nd to 4th hour duration, in normal growth state from 4th to 6th hour duration while in excessive growth state of oxide particle agglomeration and surface roughening from 6th to 8th (or more than 8th) hour duration. The coating thickness increased from 5 μm to 12 μm as oxidation duration increased from 2 h to 8 h. The increase in duration also increased surface roughness and nano hardness as well as adhesion strength of the film/substrate for oxidized samples. The nano hardness value was 10.06 ± 2.15 GPa and the critical load of failure during nano scratch testing was 554.3 ± 6.44 mN for 4 h treated sample. The untreated and oxidized samples showed a same fretting running status and fretting regime with a displacement amplitude of 200 μm while revealing different fretting failure mechanisms. It was mainly abrasive and adhesive wear under ploughing force for untreated sample, while a mix of 3-body abrasion by rolling oxide particles and severe plastic deformation under high contact stress between two ceramic materials for the oxidized samples. The oxide coating was not worn out and improved the fretting wear resistance of titanium alloy. - Highlights: • A thickness of 5–12 μm rutile TiO{sub 2} coating formed under different oxidation durations. • Weight gain with respect to oxidation duration obeyed linear

  12. Nd:YOV4 laser surface texturing on DLC coating: Effect on morphology, adhesion, and dry wear behavior

    Science.gov (United States)

    Surfaro, Maria; Giorleo, Luca; Montesano, Lorenzo; Allegri, Gabriele; Ceretti, Elisabetta; La Vecchia, Giovina Marina

    2018-05-01

    The surface of structural components is usually subjected to higher stresses, greater wear or fatigue damage, and more direct environmental exposure than the inner parts. For this reason, the interest to improve superficial properties of items is constantly increasing in different fields as automotive, electronic, biomedical, etc. Different approaches can be used to achieve this goal: case hardening by means of superficial heat treatments like carburizing or nitriding, deposition of thin or thick coatings, roughness modification, etc. Between the available technologies to modify components surface, Laser Surface Texturing (LST) has already been recognized in the last decade as a process, which improves the tribological properties of various parts. Based on these considerations the aim of the present research work was to realize a controlled laser texture on a Diamond-like Carbon (DLC) thin coating (about 3 µm thick) without damaging both the coating itself and the substrate. In particular, the effect of laser process parameters as marking speed and loop cycle were investigated in terms of texture features modifications. Both qualitative and quantitative analyses of the texture were executed by using a scanning electron microscope and a laser probe system to select the proper laser parameters. Moreover, the effect of the selected texture on the DLC nanohardness, adhesion and wear behavior was pointed out.

  13. Mechanical Properties and Wear Behavior of AA5182/WC Nanocomposite Fabricated by Friction Stir Welding at Different Tool Traverse Speeds

    Science.gov (United States)

    Paidar, Moslem; Asgari, Ali; Ojo, Olatunji Oladimeji; Saberi, Abbas

    2018-03-01

    Grain growth inhibition at the heat-affected zone, improved weld strength and superior tribological properties of welds are desirable attributes of modern manufacturing. With the focused on these attributes, tungsten carbide (WC) nanoparticles were employed as reinforcements for the friction stir welding of 5-mm-thick AA5182 aluminum alloy by varying tool traverse speeds. The microstructure, microhardness, ultimate tensile strength, fracture and wear behavior of the resultant WC-reinforced welds were investigated, while unreinforced AA5182 welds were employed as controls for the study. The result shows that the addition of WC nanoparticles causes substantial grain refinement within the weld nugget. A decrease in traverse speed caused additional particle fragmentation, improved hardness value and enhanced weld strength in the reinforced welds. Improved wear rate and friction coefficient of welds were attained at a reduced traverse speed of 100 mm/min in the WC-reinforced welds. This improvement is attributed to the effects of reduced grain size/grain fragmentation and homogeneous dispersion of WC nanoparticles within the WC-reinforced weld nugget.

  14. Friction and wear mechanisms in MoS2/Sb2O3/Au nanocomposite coatings

    International Nuclear Information System (INIS)

    Scharf, T.W.; Kotula, P.G.; Prasad, S.V.

    2010-01-01

    Fundamental phenomena governing the tribological mechanisms in sputter deposited amorphous MoS 2 /Sb 2 O 3 /Au nanocomposite coatings are reported. In dry environments the nanocomposite has the same low friction coefficient as pure MoS 2 (∼0.007). However, unlike pure MoS 2 coatings, which wear through in air (50% relative humidity), the composite coatings showed minimal wear, with wear factors of ∼1.2-1.4 x 10 -7 mm 3 Nm -1 in both dry nitrogen and air. The coatings exhibited non-Amontonian friction behavior, with the friction coefficient decreasing with increasing Hertzian contact stress. Cross-sectional transmission electron microscopy of wear surfaces revealed that frictional contact resulted in an amorphous to crystalline transformation in MoS 2 with 2H-basal (0 0 0 2) planes aligned parallel to the direction of sliding. In air the wear surface and subsurface regions exhibited islands of Au. The mating transfer films were also comprised of (0 0 0 2)-oriented basal planes of MoS 2 , resulting in predominantly self-mated 'basal on basal' interfacial sliding and, thus, low friction and wear.

  15. Wear Characteristics of Ceramic Coating Materials by Plasma Spray under the Lubricative Environment

    International Nuclear Information System (INIS)

    Kim, Chang Ho

    2001-02-01

    This paper is to investigate the wear behaviors of two types of ceramics, Al 2 O 3 and TiO 2 , by coated plasma thermal spray method under the lubricative environment. The lubricative environments are grease fluids, a general hydraulic fluids, and bearing fluids. The wear testing machine used a pin on disk type. Wear characteristics, which were friction force, friction coefficient and the specific wear rate, according to the lubricative environments were obtained at the four kinds of load, and the sliding velocity is 0.2m/sec. After the wear experiments, the wear surfaces of the each test specimen were observed by a scanning electronic microscope. The obtained results are as follows. : 1. The friction coefficients of TiO 2 coating materials are 0.11 ∼ 0.16 range and those of Al 2 O 3 are 0.24 ∼ 0.39. The friction coefficient of two coating materials is relative to the hardness of these materials. 2. The friction coefficient of TiO 2 coating materials in three lubricative environments is almost same to each other in spite of changing of applied loads. 3. The friction coefficient of Al 2 O 3 coating materials is more large in low load than high load. And the friction coefficient in grease is more large than a general hydraulic and bearing fluids had almost same friction coefficient. 4. The specific wear rate in TiO 2 is greatly increasing according to change the applied loads, but that in Al 2 O 3 is slightly. And the wear in grease is the least among three lubricating environments. 5. On the wear mechanism by SEM image observation, the wear of Al 2 O 3 is adhesive wear and TiO 3 is abrasive wear

  16. Modeling and evaluation of the influence of micro-EDM sparking state settings on the tool electrode wear behavior

    DEFF Research Database (Denmark)

    Puthumana, Govindan

    2017-01-01

    materials characterized by considerable wear ofthe tool used for material removal. This paper presents an investigation involving modeling and estimation of the effect of settings for generation of discharges in stable conditions of micro-EDM on the phenomenon of tool electrode wear. A stable sparking...... a condition for the minimum tool wear for this micro-EDM process configuration....

  17. Friction and wear behavior of TiC particle reinforced ZA43 matrix composites

    Institute of Scientific and Technical Information of China (English)

    谢贤清; 张荻; 刘金水; 吴人洁

    2001-01-01

    TiC/ZA43 composites were fabricated by XDTM and stirring-casting techniques. The tribology properties of the unreinforced ZA43 alloy and the composites were studied by using a block-on-ring apparatus. Experimental results show that the incorporation of TiC particles improves the microstructure of ZA43 matrix alloy. The coefficient of friction μ and the width of worn groove decrease with the increase of TiC volume fraction φ(TiC). The width of worn groove and μ of the composite during wear testing increase with increasing the applied load. Metallographic examinations reveal that unreinforced ZA43 alloy has deep ploughing grooves with obvious adhesion phenomenon, whereas TiC/ZA43 composites have smooth worn surface. Delamination formation is related to the fatigue cracks and the shear cracks on the surface.

  18. Micro-scale abrasive wear behavior of medical implant material Ti-25Nb-3Mo-3Zr-2Sn alloy on various friction pairs.

    Science.gov (United States)

    Wang, Zhenguo; Huang, Weijiu; Ma, Yanlong

    2014-09-01

    The micro-scale abrasion behaviors of surgical implant materials have often been reported in the literature. However, little work has been reported on the micro-scale abrasive wear behavior of Ti-25Nb-3Mo-3Zr-2Sn (TLM) titanium alloy in simulated body fluids, especially with respect to friction pairs. Therefore, a TE66 Micro-Scale Abrasion Tester was used to study the micro-scale abrasive wear behavior of the TLM alloy. This study covers the friction coefficient and wear loss of the TLM alloy induced by various friction pairs. Different friction pairs comprised of ZrO2, Si3N4 and Al2O3 ceramic balls with 25.4mm diameters were employed. The micro-scale abrasive wear mechanisms and synergistic effect between corrosion and micro-abrasion of the TLM alloy were investigated under various wear-corrosion conditions employing an abrasive, comprised of SiC (3.5 ± 0.5 μm), in two test solutions, Hanks' solution and distilled water. Before the test, the specimens were heat treated at 760°C/1.0/AC+550°C/6.0/AC. It was discovered that the friction coefficient values of the TLM alloy are larger than those in distilled water regardless of friction pairs used, because of the corrosive Hanks' solution. It was also found that the value of the friction coefficient was volatile at the beginning of wear testing, and it became more stable with further experiments. Because the ceramic balls have different properties, especially with respect to the Vickers hardness (Hv), the wear loss of the TLM alloy increased as the ball hardness increased. In addition, the wear loss of the TLM alloy in Hanks' solution was greater than that in distilled water, and this was due to the synergistic effect of micro-abrasion and corrosion, and this micro-abrasion played a leading role in the wear process. The micro-scale abrasive wear mechanism of the TLM alloy gradually changed from two-body to mixed abrasion and then to three-body abrasion as the Vickers hardness of the balls increased. Copyright

  19. Slide 24

    Indian Academy of Sciences (India)

    On one of the days many scientists were relaxing at a beach near Boston. Amongst those were some well-known ones, von Laue, Lawrence Bragg, Paul Ewald, Raman, Patterson, Hermann Mark, JD Bernal and others. A young lady with a camera rushed to get a photograph of von Laue wearing very brief swimming trunks.

  20. Characterization of transfer layers on steel surfaces sliding against diamondlike carbon in dry nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, A.; Bindal, C.; Pagan, J. [Argonne National Lab., IL (United States); Wilbur, P. [Colorado State Univ., Fort Collins, CO (United States). Dept. of Mechanical Engineering

    1995-03-01

    Transfer layers on sliding steel surfaces play important roles in tribological performance of diamondlike carbon films. This study investigated the nature of transfer layers formed on M50 balls during sliding against diamondlike carbon (DLC) films (1.5 {mu}m thick) prepared by ion-beam deposition. Long-duration sliding tests were performed with steel balls sliding against the DLC coatings in dry nitrogen at room temperature and zero humidity. Test results indicated that the friction coefficients of test pairs were initially 0.12 but decreased steadily with sliding distance to 0.02-0.03 and remained constant throughout the tests, which lasted for more than 250,000 sliding cycles (30 km). This low-friction regime appeared to coincide with the formation of a carbon-rich transfer layer on the sliding surfaces of M50 balls. Micro-laser-Raman spectroscopy and electron microscopy were used to elucidate the structure and chemistry of these transfer layers and to reveal their possible role in the wear and friction behavior of DLC-coated surfaces.

  1. Effect of deep cryogenic treatment and tempering on microstructure and mechanical behaviors of a wear-resistant austempered alloyed bainitic ductile iron

    Directory of Open Access Journals (Sweden)

    Chen Liqing

    2015-01-01

    Full Text Available In this paper, the effect of deep cryogenic treatment in combination with conven- tional heat treatment process was investigated on microstructure and mechanical behaviors of alloyed bainitic ductile iron. Three processing schedules were employed to treat this alloyed ductile iron including direct tempering treatment, tempering.+deep cryogenic treatment and deep cryogenic treatment.+tempering treatments. The microstructure and mechanical behavior, especially the wear resistance, have been evaluated after treated by these three schedules. The results show that martensite microstructure can be obviously refined and the precipitation of dispersed carbides is promoted by deep cryogenic treatment at .−196 ∘C for 3 h after tempered at 450 ∘C for 2 h. In this case, the alloyed bainitic ductile iron possesses rather high hardness and wear-resistance than those processed by other two schedules. The main wear mechanism of the austempered alloyed ductile iron with deep cryogenic treatment and tempering is micro-cutting wear in association with plastic deformation wear.

  2. Wear behavior of A356/M{sub 7}C{sub 3} and A356/SiC particulate metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Turhan, H. [Univ. of Firat, Dept. of Metallurgy, Elazig (Turkey); Yilmaz, O. [Univ. of Firat, Dept. of Metallurgical Engineering, Elazig (Turkey)

    2002-06-01

    The stability of M{sub 7}C{sub 3} carbides as reinforcement for A356 materials for tribological applications has been investigated. For this purpose, A356/M{sub 7}C{sub 3}, A356/SiC and A356/M{sub 7}C{sub 3}/SiC composites were prepared by powder metallurgy and tested at room temperature against SAE 4620 steel ring and AISI 304 stainless steel counterfaces under loads of 10 - 150 N. For comparison, also unreinforced A356 specimens were processed and tested under the same conditions. The tribological behavior was evaluated by microstructural examination of the wear-effected zones and by weight loss measurements of the specimens and counterfaces. The wear behavior of A356/M{sub 7}C{sub 3} composite gave an excellent result as function of the applied load because the M{sub 7}C{sub 3} particles act as load-bearing elements due to their excellent bonding to the Al matrix, and their interfaces withtood the wear stresses even at the highest applied load. Moreover, the M{sub 7}C{sub 3} particles limited the incorporation of wear debris into the Al matrix and reduced the wear damage occasioned to the steel counterfaces compared to that of A356 Al alloy. (orig.)

  3. PWR control rods wear by vibrations induced by coolant fluid

    International Nuclear Information System (INIS)

    Reynier, R.

    1997-01-01

    Flow induced vibrations in pressurised water reactors generate the wear of control rods against their guidance systems. Alternate sliding (at 320 deg. C in water) and impact-sliding tests (at room temperature in air) were carried out on 304 L austenitic stainless steel control rods' claddings. Microstructural analysis were made on the wear scars of the tube specimen using Scanning ELectron Microscopy, microhardness measurements and X-ray diffractometry. The alternate sliding leads to an important mass loss, a strong plastic deformation due to the strain hardening of the surface layers and generates strong compressive residual stresses. These results are specific to a severe wear case. Therefore, the impact-sliding mode induces martensitic phase, a cracked oxide layer and a compressive residual stresses weaker than those created in the alternate sliding case. This type of motion leads to a milder wear of the control rods

  4. Comprehensive study of the abrasive wear and slurry erosion behavior of an expanded system of high chromium cast iron and microstructural modification for enhanced wear resistance

    Science.gov (United States)

    Chung, Reinaldo Javier

    High chromium cast irons (HCCIs) have been demonstrated to be an effective material for a wide range of applications in aggressive environments, where resistances to abrasion, erosion and erosion-corrosion are required. For instance, machinery and facilities used in mining and extraction in Alberta's oil sands suffer from erosion and erosion-corrosion caused by silica-containing slurries, which create challenges for the reliability and maintenance of slurry pumping systems as well as other processing and handling equipment. Considerable efforts have been made to determine and understand the relationship between microstructural features of the HCCIs and their wear performance, in order to guide the material selection and development for specific service conditions with optimal performance. The focus was previously put on a narrow group of compositions dictated by ASTM A532. However, with recent advances in casting technology, the HCCI compositional range can be significantly expanded, which potentially brings new alloys that can be superior to those which are currently employed. This work consists of three main aspects of study. The first one is the investigation of an expanded system of white irons with their composition ranging from 1 to 6 wt.% C and 5 to 45 wt.% Cr, covering 53 alloys. This work has generated wear and corrosion maps and established correlation between the performance and microstructural features for the alloys. The work was conducted in collaboration with the Materials Development Center of Weir Minerals in Australia, and the results have been collected in a database that is used by the company to guide materials selection for slurry pump components in Alberta oil sands and in other mining operations throughout the world. The second part consists of three case studies on effects of high chromium and high carbon, respectively, on the performance of the HCCIs. The third aspect is the development of an approach to enhance the wear resistance of

  5. Modeling and Investigation of the Wear Resistance of Salt Bath Nitrided Aisi 4140 via ANN

    Science.gov (United States)

    Ekinci, Şerafettin; Akdemir, Ahmet; Kahramanli, Humar

    2013-05-01

    Nitriding is usually used to improve the surface properties of steel materials. In this way, the wear resistance of steels is improved. We conducted a series of studies in order to investigate the microstructural, mechanical and tribological properties of salt bath nitrided AISI 4140 steel. The present study has two parts. For the first phase, the tribological behavior of the AISI 4140 steel which was nitrided in sulfinuz salt bath (SBN) was compared to the behavior of the same steel which was untreated. After surface characterization using metallography, microhardness and sliding wear tests were performed on a block-on-cylinder machine in which carbonized AISI 52100 steel discs were used as the counter face. For the examined AISI 4140 steel samples with and without surface treatment, the evolution of both the friction coefficient and of the wear behavior were determined under various loads, at different sliding velocities and a total sliding distance of 1000 m. The test results showed that wear resistance increased with the nitriding process, friction coefficient decreased due to the sulfur in salt bath and friction coefficient depended systematically on surface hardness. For the second part of this study, four artificial neural network (ANN) models were designed to predict the weight loss and friction coefficient of the nitrided and unnitrided AISI 4140 steel. Load, velocity and sliding distance were used as input. Back-propagation algorithm was chosen for training the ANN. Statistical measurements of R2, MAE and RMSE were employed to evaluate the success of the systems. The results showed that all the systems produced successful results.

  6. Dry sliding tribological behavior and mechanical properties of Al2024–5 wt.%B4C nanocomposite produced by mechanical milling and hot extrusion

    International Nuclear Information System (INIS)

    Abdollahi, Alireza; Alizadeh, Ali; Baharvandi, Hamid Reza

    2014-01-01

    Highlights: • Nanostructured Al2024 and Al2024–B 4 C nanocomposite prepared via mechanical milling. • The milled powders formed by hot pressing and then exposed to hot extrusion. • Tribological behavior and mechanical properties of samples were investigated. • Al2024–B 4 C nanocomposite showed a better wear resistance and mechanical properties. - Abstract: In this paper, tribological behavior and mechanical properties of nanostructured Al2024 alloy produced by mechanical milling and hot extrusion were investigated before and after adding B 4 C particles. Mechanical milling was used to synthesize the nanostructured Al2024 in attrition mill under argon atmosphere up to 50 h. A similar process was used to produce Al2024–5 wt.%B 4 C composite powder. The milled powders were formed by hot pressing and then were exposed to hot extrusion in 750 °C with extrusion ratio of 10:1. To study the microstructure of milled powders and hot extruded samples, optical microscopy, transmission electron microscopy and scanning electron microscopy (SEM) equipped with an energy dispersive X-ray spectrometer (EDS) were used. The mechanical properties of samples were also compared together using tension, compression and hardness tests. The wear properties of samples were studied using pin-on-disk apparatus under a 20 N load. The results show that mechanical milling decreases the size of aluminum matrix grains to less than 100 nm. The results of mechanical and wear tests also indicate that mechanical milling and adding B 4 C particles increase strength, hardness and wear resistance of Al2024 and decrease its ductility remarkably

  7. Slide layout and integrated design (SLIDE) program

    International Nuclear Information System (INIS)

    Roberts, S.G.

    1975-01-01

    SLIDE is a FORTRAN IV program for producing 35 mm color slides on the Control Data CYBER-74. SLIDE interfaces with the graphics package, DISSPLA, on the CYBER-74. It was designed so that persons with no previous computer experience can easily and quickly generate their own textual 35 mm color slides for verbal presentations. SLIDE's features include seven different colors, five text sizes, ten tab positions, and two page sizes. As many slides as desired may be produced during any one run of the program. Each slide is designed to represent an 8 1 / 2 in. x 11 in. or an 11 in. x 8 1 / 2 in. page. The input data cards required to run the SLIDE program and the program output are described. Appendixes contain a sample program run showing input, output, and the resulting slides produced and a FORTRAN listing of the SLIDE program. (U.S.)

  8. Characterization and wear performance of boride phases over tool steel substrates

    Directory of Open Access Journals (Sweden)

    Edgar E Vera Cárdenas

    2016-02-01

    Full Text Available This research work was conducted to characterize boride phases, obtained from the powder-pack process, on AISI H13 and D2 steel substrates, and investigate their tribological behavior. The boriding was developed at a temperature of 1273 K with an exposure time of 8 h. X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were conducted on the borided material to characterize the presence of the FeB, Fe2B, and CrB phases and the distribution of heavy elements on the surface of the substrates. The adherence of the boride layers was evaluated, in a qualitative form, through the Daimler-Benz Rockwell-C indentation technique. Sliding wear tests were then performed using a reciprocating wear test machine. All tests were conducted in dry conditions at room temperature. A frequency of 10 Hz and 15-mm sliding distance were used. The applied Hertzian pressure was 2.01 GPa. Scanning electron microscopy was used to observe and analyze the wear mechanisms. Additionally, the variation of the friction coefficient versus the number of cycles was obtained. Experimental results showed that the characteristic wear mechanism for the borided surface was plastic deformation and mild abrasive wear; for unborided substrates, cracking and spalling were observed.

  9. Tibiofemoral wear in standard and non-standard squat: implication for total knee arthroplasty.

    Science.gov (United States)

    Fekete, Gusztáv; Sun, Dong; Gu, Yaodong; Neis, Patric Daniel; Ferreira, Ney Francisco; Innocenti, Bernardo; Csizmadia, Béla M

    2017-01-01

    Due to the more resilient biomaterials, problems related to wear in total knee replacements (TKRs) have decreased but not disappeared. In the design-related factors, wear is still the second most important mechanical factor that limits the lifetime of TKRs and it is also highly influenced by the local kinematics of the knee. During wear experiments, constant load and slide-roll ratio is frequently applied in tribo-tests beside other important parameters. Nevertheless, numerous studies demonstrated that constant slide-roll ratio is not accurate approach if TKR wear is modelled, while instead of a constant load, a flexion-angle dependent tibiofemoral force should be involved into the wear model to obtain realistic results. A new analytical wear model, based upon Archard's law, is introduced, which can determine the effect of the tibiofemoral force and the varying slide-roll on wear between the tibiofemoral connection under standard and non-standard squat movement. The calculated total wear with constant slide-roll during standard squat was 5.5 times higher compared to the reference value, while if total wear includes varying slide-roll during standard squat, the calculated wear was approximately 6.25 times higher. With regard to non-standard squat, total wear with constant slide-roll during standard squat was 4.16 times higher than the reference value. If total wear included varying slide-roll, the calculated wear was approximately 4.75 times higher. It was demonstrated that the augmented force parameter solely caused 65% higher wear volume while the slide-roll ratio itself increased wear volume by 15% higher compared to the reference value. These results state that the force component has the major effect on wear propagation while non-standard squat should be proposed for TKR patients as rehabilitation exercise.

  10. Fretting and wear of stainless and ferritic steels in LMFBR steam generators

    International Nuclear Information System (INIS)

    Lewis, M.W.J.; Campbell, C.S.

    1981-01-01

    Steam generators for LMFBR's may be subject to both fretting wear as a result of flow-induced vibrations and to wear from larger amplitude sliding movements from thermal changes. Results of tests simulating the latter are given for stainless and ferritic steels. For the assessment of fretting wear damage, vibration assessments must be combined with data on specific wear rates. Test mechanisms used to study fretting in sodium covering impact, impact-slide and pure rubbing are described and results presented. (author)

  11. Wear behavior of carbon fiber/aluminium-composites during abrasive loading; Verschleissverhalten von Kohlenstoffaser/Aluminium-Verbunden unter abrasiver Beanspruchung

    Energy Technology Data Exchange (ETDEWEB)

    Wielage, B.; Dorner, A. [Technische Univ. Chemnitz (Germany). Lehrstuhl fuer Verbundwerkstoffe

    1998-07-01

    Abrasive wear resistance of aluminium is significantly improved by the reinforcement with a high volume percentage of carbon fibres. The wear of unreinforced aluminium after scratching by a diamond indenter can be described as pure microgrooving without any micro-chipping. After integration of 70 vol.-% carbon fibers the damage mechanism is considerably altered and a great amount of micro-chipping occurs. The abrasive wear is strongly influenced by the fiber orientation. The best wear resistance is observed when the fibers are orientated perpendicular to the wear surface. (orig.) [Deutsch] Die Verstaerkung von Aluminium mit einem hohen Volumengehalt endloser Kohlenstoffasern verbessert erkennbar dessen Resistenz gegenueber Abrasionsverschleiss. Der Verschleiss von unverstaerktem Aluminium infolge des Ritzens mit einem Diamantindenter erfolgt in Form von reinem Mikrofurchen ohne Spanbildung. Aufgrund der Integration von 70 Vol.-% Kohlenstoffasern wird eine erhebliche Zunahme des Schaedigungsmechanismus Mikrospanen festgestellt. Die Faserorientierung hat merklichen Einfluss auf die Sensibilitaet gegenueber Abrasion. Orientierung der anisotropen Kohlenstoffasern senkrecht zur Verschleissoberflaeche bedingt den geringsten Abrasionsverschleiss. (orig.)

  12. Failure mechanism of coated biomaterials under high impact-sliding contact stresses

    Science.gov (United States)

    Chen, Ying

    This study uses a newly developed testing method--- inclined cyclic impact-sliding test to investigate the failure behaviors of different types of biomaterials, (SS316L, Ti6Al4V and CoCr) coated by different coatings (TiN, DLC and PEO), under extremely high dynamic contact stress conditions. This test method can simulate the combined impact and sliding/rolling loading conditions, which is very practical in many aspects of commercial usages. During the tests, fatigue cracking, chipping, peeling and material transferring were observed in damaged area. This research is mainly focused on the failure behaviors of load-bearing materials which cyclic impacting and sliding are always involved. This purpose was accomplished in the three stages: First, impact-sliding test was carried out on TiN coated unhardened M2. It was found that soft substrate can cause early failure of coating due to the considerable plastic deformation in the substrate. In this case, stronger substrate is required to support coating better when tested under high contact stresses. Second, PEO coated Ti-6Al-4V was tested under pure sliding and impact-sliding wear conditions. PEO coating was found not strong enough to afford the high contact pressure under cyclic impact-sliding wear test due to its porous surface structure. However, the wear performance of PEO coating was enhanced due to the sub-stoichiometric oxide. To sum up, for load-bearing biomedical implants involved in high impacting movement, PEO coating may not be a promising surface protection. Third, the dense, smooth PVD/CVD bio-inert coatings were reconsidered. DLC and TiN coatings, combined by different substrates together with different interface materials were tested under the cyclic impact-sliding test using a set of proper loading. The results show that to choose a proper combination of coating, interface and substrate based on their mechanical properties is of great importance under the test condition. Hard substrates provide support

  13. Effect of heat treatment on friction and wear behavior of al-6061 composite reinforced with 10% submicron Al2O3 particles

    International Nuclear Information System (INIS)

    AlQutub, Amro M

    2009-01-01

    The present research aims at investigating experimentally the effect of heat treatment on the hardness, wear behavior, and friction properties of 6061 Al composite reinforced with sub-micron Al2O3 (10% vol.) produced by powder metallurgy. Heat treatment of the as-received composite starts by the solution treatment at a temperature of 550 degree C for a period of two hours followed by quenching in chilled water and then age hardening at 175 degree C for different periods. It is illustrated that heat treatment has relatively small effect on the hardness of the composite. This can be attributed to the large interface areas between the matrix and the sub-micron alumina in the composite, which reduces the whole concentration of vacancies in the matrix. The result is reduced efficiency of age hardening. For this reason, wear and friction tests were limited to the heat treated composite with four hours aging only. A pin-on-disc tribometer was used to conduct wear and friction tests against AISI 4140 at room temperature for both as-received composite and heat treated composite (with four hours of aging) for comparison. Wear tests indicate that heat treatment has the advantage of increasing transition load to severe wear by 30% compared to as-received composite. On the other hand, at high loads heat treatment results in larger delaminated flakes on the worn surface, indicating reduced fracture toughness. This, in turn, resulted in higher wear rates compared to the as-received composite. Dry friction coefficient is practically unaffected by the heat treatment. (author)

  14. Wear behavior of the surface alloyed AISI 1020 steel with Fe-Nb-B by TIG welding technique

    Energy Technology Data Exchange (ETDEWEB)

    Kilinc, B., E-mail: bkilinc@sakarya.edu.tr; Durmaz, M.; Abakay, E. [Department of Metallurgical and Materials Engineering, Institute of Arts and Sciences, SakaryaUniversity, Esentepe Campus, 54187Sakarya (Turkey); Sen, U.; Sen, S. [Department of Metallurgical and Materials Engineering, Engineering Faculty, Sakarya University, Esentepe Campus, 54187 Sakarya (Turkey)

    2015-03-30

    Weld overlay coatings also known as hardfacing is a method which involves melting of the alloys and solidification for applied coatings. Recently hardfacing by welding has become a commonly used technique for improvement of material performance in extreme (high temperature, impact/abrasion, erosion, etc.) conditions.In the present study, the coatings were produced from a mixture of ferrous niobium, ferrous boron and iron powders in the ranges of -45µm particle size with different ratio. Fe{sub 12}Nb{sub 5}B{sub 3} and Fe{sub 2}NbBalloys were coated on the AISI 1020 steel surface by TIG welding. The phases formed in the coated layer are Fe{sub 2}B, NbB{sub 2}, NbFeB and Fe0,2 Nb{sub 0,8} phases. The hardness of the presence phases are changing between 1689±85 HV{sub 0.01}, and 181±7 HV{sub 0.1}. Microstructural examinations were realized by optical and scanning electron microscopy. The wear and friction behaviors of Fe{sub 12}Nb{sub 5}B{sub 3} and Fe2NbB realized on the AISI 1020 steel were investigated by the technique of TIG welding by using ball-on-disk arrangement against alumina ball.

  15. Wear behavior of the surface alloyed AISI 1020 steel with Fe-Nb-B by TIG welding technique

    Science.gov (United States)

    Kilinc, B.; Durmaz, M.; Abakay, E.; Sen, U.; Sen, S.

    2015-03-01

    Weld overlay coatings also known as hardfacing is a method which involves melting of the alloys and solidification for applied coatings. Recently hardfacing by welding has become a commonly used technique for improvement of material performance in extreme (high temperature, impact/abrasion, erosion, etc.) conditions.In the present study, the coatings were produced from a mixture of ferrous niobium, ferrous boron and iron powders in the ranges of -45µm particle size with different ratio. Fe12Nb5B3 and Fe2NbBalloys were coated on the AISI 1020 steel surface by TIG welding. The phases formed in the coated layer are Fe2B, NbB2, NbFeB and Fe0,2 Nb0,8 phases. The hardness of the presence phases are changing between 1689±85 HV0.01, and 181±7 HV0.1. Microstructural examinations were realized by optical and scanning electron microscopy. The wear and friction behaviors of Fe12Nb5B3 and Fe2NbB realized on the AISI 1020 steel were investigated by the technique of TIG welding by using ball-on-disk arrangement against alumina ball.

  16. Microstructure, Wear Resistance and Oxidation Behavior of Ni-Ti-Si Coatings Fabricated on Ti6Al4V by Laser Cladding.

    Science.gov (United States)

    Zhuang, Qiaoqiao; Zhang, Peilei; Li, Mingchuan; Yan, Hua; Yu, Zhishui; Lu, Qinghua

    2017-10-30

    The Ni-Ti-Si composite coatings were successfully fabricated on Ti6Al4V by laser cladding. The microstructure were studied by SEM (scanning electron microscopy) and EDS (energy dispersive spectrometer). It has been found that Ti₂Ni and Ti₅Si₃ phases exist in all coatings, and some samples have TiSi₂ phases. Moreover, due to the existence of these phases, coatings presented relatively higher microhardness than that of the substrate (826 HV (Vickers hardness)) and the microhardness value of coating 3 is about twice larger than that of the substrate. During the dry sliding friction and wear test, due to the distribution of the relatively ductile phase of Ti₂Ni and reinforcement phases of Ti₅Si₃ and TiSi₂, the coatings performed good wear resistance. The oxidation process contains two stages: the rapid oxidation and slow oxidation by high temperature oxidation test at 800 °C for 50 h. Meanwhile, the value of the oxidation weight gain of the substrate is approximately three times larger than that of the coating 4. During the oxidation process, the oxidation film formed on the coating is mainly consisted of TiO₂, Al₂O₃ and SiO₂. Phases Ti₂Ni, Ti₅Si₃, TiSi₂ and TiSi were still found and it could be responsible for the improvement in oxidation resistance of the coatings by laser cladding.

  17. Microstructure, Wear Resistance and Oxidation Behavior of Ni-Ti-Si Coatings Fabricated on Ti6Al4V by Laser Cladding

    Directory of Open Access Journals (Sweden)

    Qiaoqiao Zhuang

    2017-10-01

    Full Text Available The Ni-Ti-Si composite coatings were successfully fabricated on Ti6Al4V by laser cladding. The microstructure were studied by SEM (scanning electron microscopy and EDS (energy dispersive spectrometer. It has been found that Ti2Ni and Ti5Si3 phases exist in all coatings, and some samples have TiSi2 phases. Moreover, due to the existence of these phases, coatings presented relatively higher microhardness than that of the substrate (826 HV (Vickers hardness and the microhardness value of coating 3 is about twice larger than that of the substrate. During the dry sliding friction and wear test, due to the distribution of the relatively ductile phase of Ti2Ni and reinforcement phases of Ti5Si3 and TiSi2, the coatings performed good wear resistance. The oxidation process contains two stages: the rapid oxidation and slow oxidation by high temperature oxidation test at 800 °C for 50 h. Meanwhile, the value of the oxidation weight gain of the substrate is approximately three times larger than that of the coating 4. During the oxidation process, the oxidation film formed on the coating is mainly consisted of TiO2, Al2O3 and SiO2. Phases Ti2Ni, Ti5Si3, TiSi2 and TiSi were still found and it could be responsible for the improvement in oxidation resistance of the coatings by laser cladding.

  18. Contact damage failure analyses of fretting wear behavior of the metal stem titanium alloy-bone cement interface.

    Science.gov (United States)

    Zhang, Lanfeng; Ge, Shirong; Liu, Hongtao; Wang, Qingliang; Wang, Liping; Xian, Cory J

    2015-11-01

    Although cemented titanium alloy is not favored currently in the Western world for its poor clinical and radiography outcomes, its lower modulus of elasticity and good biocompatibility are instrumental for its ability supporting and transforming physical load, and it is more suitable for usage in Chinese and Japanese populations due to their lower body weights and unique femoral characteristics. Through various friction tests of different cycles, loads and conditions and by examining fretting hysteresis loops, fatigue process curves and wear surfaces, the current study investigated fretting wear characteristics and wear mechanism of titanium alloy stem-bone cement interface. It was found that the combination of loads and displacement affected the wear quantity. Friction coefficient, which was in an inverse relationship to load under the same amplitude, was proportional to amplitudes under the same load. Additionally, calf serum was found to both lubricate and erode the wear interface. Moreover, cement fatigue contact areas appeared black/oxidative in dry and gruel in 25% calf serum. Fatigue scratches were detected within contact areas, and wear scars were found on cement and titanium surfaces, which were concave-shaped and ring concave/ convex-shaped, respectively. The coupling of thermoplastic effect and minimal torque damage has been proposed to be the major reason of contact damage. These data will be important for further studies analyzing metal-cement interface failure performance and solving interface friction and wear debris production issues. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. A study on erosive wear behavior of HVOF sprayed nanostructured WC-CoCr coatings

    International Nuclear Information System (INIS)

    Thakur, Lalit; Arora, Navneet

    2013-01-01

    WC-CoCr cermet coatings were deposited on stainless steel substrate using high-velocity oxy-fuel (HVOF) thermal spray process. The coatings were developed with two different thermal spray powders: one has WC grains of conventional micron size and the other is composed of nanosized (near-nanostructured) grains. HVOF spraying was assisted with in-flight particle temperature and velocity measurement system to control the process parameters that have resulted in quality coatings. Cavitation erosion testing was performed using a vibratory test apparatus based on ASTM standard G32-98. Surface morphology of powders and coatings was examined using the FESEM images, and phase identification was performed by XRD analysis. The erosion behavior of coatings and mechanism of material removal was discussed by examining the microstructure images of worn-out surfaces. WC-CoCr cermet coating deposited with nanosized WC grains exhibited higher cavitation erosion resistance as compared to conventional coating.

  20. A study on erosive wear behavior of HVOF sprayed nanostructured WC-CoCr coatings

    Energy Technology Data Exchange (ETDEWEB)

    Thakur, Lalit; Arora, Navneet [Indian Institute of Technology Roorkee, Roorkee (India)

    2013-05-15

    WC-CoCr cermet coatings were deposited on stainless steel substrate using high-velocity oxy-fuel (HVOF) thermal spray process. The coatings were developed with two different thermal spray powders: one has WC grains of conventional micron size and the other is composed of nanosized (near-nanostructured) grains. HVOF spraying was assisted with in-flight particle temperature and velocity measurement system to control the process parameters that have resulted in quality coatings. Cavitation erosion testing was performed using a vibratory test apparatus based on ASTM standard G32-98. Surface morphology of powders and coatings was examined using the FESEM images, and phase identification was performed by XRD analysis. The erosion behavior of coatings and mechanism of material removal was discussed by examining the microstructure images of worn-out surfaces. WC-CoCr cermet coating deposited with nanosized WC grains exhibited higher cavitation erosion resistance as compared to conventional coating.

  1. Effects of Load and Speed on Wear Rate of Abrasive Wear for 2014 Al Alloy

    Science.gov (United States)

    Odabas, D.

    2018-01-01

    In this paper, the effects of the normal load and sliding speed on wear rate of two-body abrasive wear for 2014 Al Alloy were investigated in detail. In order to understand the variation in wear behaviour with load and speed, wear tests were carried out at a sliding distance of 11 m, a speed of 0.36 m/s, a duration of 30 s and loads in the range 3-11 N using 220 grit abrasive paper, and at a speed range 0.09-0.90 m/s, a load of 5 N and an average sliding distance of 11 m using abrasive papers of 150 grit size under dry friction conditions. Before the wear tests, solution treatment of the 2014 Al alloy was carried out at temperatures of 505 and 520 °C for 1 h in a muffle furnace and then quenched in cold water at 15 °C. Later, the ageing treatment was carried out at 185 °C for 8 h in the furnace. Generally, wear rate due to time increased linearly and linear wear resistance decreased with increasing loads. However, the wear rate was directly proportional to the load up to a critical load of 7 N. After this load, the slope of the curves decreased because the excessive deformation of the worn surface and the instability of the abrasive grains began to increase. When the load on an abrasive grain reaches a critical value, the groove width is about 0.17 of the abrasive grain diameter, and the abrasive grains begin to fail. The wear rate due to time increased slightly as the sliding speed increased in the range 0.09-0.90 m/s. The reason for this is that changes arising from strain rate and friction heating are expected with increasing sliding speeds.

  2. Effects of prior cold work on corrosion and corrosive wear of copper in HNO3 and NaCl solutions

    International Nuclear Information System (INIS)

    Yin Songbo; Li, D.Y.

    2005-01-01

    Effects of prior cold work on corrosion and corrosive wear behavior of copper in 0.1 M HNO 3 and 3.5% NaCl solutions, respectively, were investigated using electrochemical tests, electron work function measurements, and sliding corrosive wear tests with and without cathodic protection. Optical microscope and SEM were employed to examine the microstructure and worn surfaces. It was shown that, in general, the prior cold work raised the corrosion rate, but the effect differed in different corrosive media. In both the solutions, pure mechanical wear decreased with an increase in cold work. The prior cold work had a significant influence on the corrosive wear of copper, depending on the corrosive solution and the applied load. In the 0.1 M HNO 3 solution, the ratio of the wear loss caused by corrosion-wear synergism to the total wear loss increased with the cold work and became saturated when the cold work reached a certain level. In the 3.5% NaCl solution, however, this ratio decreased initially and then became relatively stable with respect to the cold work. It was observed that wear of copper in the 3.5% NaCl solution was larger than that in 0.1 M HNO 3 solution, although copper showed lower corrosion rate in the former solution. The experimental observations and the possible mechanisms involved are discussed

  3. Wear of rolling element bearings in sodium

    International Nuclear Information System (INIS)

    Campbell, C.S.

    1976-01-01

    Rolling element bearings and related mechanisms are attractive for service in liquid sodium but it is not clear what minimum wear rate can be anticipated. For axially loaded angular contact bearings rotation is incompatible with pure rolling on both races and wear arises from the resulting ball spin. The initial pressure distributions and sizes of the contact ellipses can be calculated but will change with bearing wear. However, the most effective distribution for producing wear would be for the full loads to be borne on the tips of the contact areas, whose maximum length is given by examination of the race wear tracks. A calculation on such a basis should set a lower limit for the wear coefficient. Both the torque and instantaneous wear rate of a bearing will be similar functions of the integral over the contact areas of the product of contact pressure and radius from the ball spin axis. A better estimate of wear coefficient should be obtained by relating the average torque, the average wear, the initial torque and the initial wear where the conditions are known. Analysis of tests in sodium at 400 0 C of high speed steel and Stellite bearings by these methods indicates specific wear rates of the order of 10 -15 m 3 /N-m, not unduly out of line with the range of values found in conventional sliding tests

  4. Creep behavior and wear resistance of Al 5083 based hybrid composites reinforced with carbon nanotubes (CNTs) and boron carbide (B{sub 4}C)

    Energy Technology Data Exchange (ETDEWEB)

    Alizadeh, Ali [Faculty of Materials & Manufacturing Processes, Malek-e-Ashtar University of Technology, Tehran (Iran, Islamic Republic of); Abdollahi, Alireza, E-mail: alirezaabdollahi1366@gmail.com [Faculty of Materials & Manufacturing Processes, Malek-e-Ashtar University of Technology, Tehran (Iran, Islamic Republic of); Biukani, Hootan [Faculty of Engineering, South Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2015-11-25

    In the current research, aluminum based hybrid composite reinforced with boron carbide (B{sub 4}C) and carbon nanotubes (CNTs) was produced by powder metallurgy method. creep behavior, wear resistance, surface roughness, and hardness of the samples were investigated. To prepare the samples, Al 5083 powder was milled with boron carbide particles and carbon nanotubes using planetary ball mill under argon atmosphere with ball-to-powder weight ratio of 10:1 for 5 h. Afterwards, the milled powders were formed by hot press process at 380{sup °}C and then were sintered at 585{sup °}C under argon atmosphere for 2 h. There was shown to be an increase in hardness values of composite with an increase in B{sub 4}C content. The micrograph of worn surfaces indicate a delamination mechanism due to the presence of CNTs and abrasion mechanism in composite containing 10 vol.%B{sub 4}C. Moreover, it was shown that increasing B{sub 4}C content increases the wear resistance by 3 times under a load of 20 N and 10 times under a load of 10 N compared to CNTs-reinforced composite. surface roughness of the composite containing 5 vol.%CNT has shown to be more than other samples. The results of creep test showed that adding carbon nanotubes increases creep rate of Al 5083 alloy; however, adding B{sub 4}C decreases its creep rate. - Highlights: • Al 5083/(CNTs + B{sub 4}C) hybrid composite was produced by powder metallurgy method. • Creep behavior, wear resistance, surface roughness, and Hardness of samples were investigated. • Addition of CNTs to Al 5083 matrix reduces alloy hardness, wear resistance and creep strength. • By addition of B{sub 4}C and composite hybridization, creep strength and wear resistance increased. • Surface roughness of Al-5 vol.%CNT has shown to be more than other samples.

  5. Development of Nanofluids as Lubricant to Study Friction and Wear Behavior of Stainless Steels

    Science.gov (United States)

    Sahoo, Rashmi Ranjan; Bhattacharjee, Santu; Das, Tuhin

    A number of nanofluids have been prepared to study the effect of lubrication properties of nanofluids on stainless steels taking Kaolin and Boron Nitride (BN) as the lubricant particles and Sodium Dodecyl Sulfate (SDS), Cetyl Trimethyl Ammonium Bromide (CTAB), Sodium Hexa Meta Phosphate (SHMP) as dispersants in the same liquid medium i.e. water. A pin on disc tribometer is being used to access the tribological behaviour of the prepared nanofluids. The particle size of these particle dispersions are examined with a nanoparticle size analyzer. It has been found that the use of dispersants significantly control the particle size and tribological behavior of the nanofluids as for Boron Nitride particle with Sodium Dodecyl Sulfate (SDS) as dispersant has got a very low value of coefficient of friction being equal to 0.142 while without dispersant the value is 0.498. Similarly, in case of Kaolin water with SDS as dispersant the value of coefficient of friction obtained is 0.161 and without dispersant it is 0.333. Sodium Dodecyl Sulfate (SDS) as dispersant has resulted a very low coefficient of friction compared to other dispersants tested even though it doesn’t always assure a least particle size. The role of SDS in yielding the lowest friction has pursued significant attention for further investigation.

  6. Wear mechanisms of toughened zirconias

    International Nuclear Information System (INIS)

    Becker, P.C.; Libsch, T.A.; Rhee, S.K.

    1985-01-01

    The dry friction and wear behavior of toughened zirconias against hardened steel was studied using the falex ring and block technique. Three experimental ZrO 2 -Y 2 O 3 ceramics and two commerical ZrO 2 -MgO ceramics were investigated. Each ceramic was tested at 500 and 2000 rpm at normal loads in the range 2.3 to 40.8 kg. Significant trends in the friction and wear data were found correlating composition, test speeds, and loads. Microstructural examination of the ring, ceramic block, and wear debris has shown that the wear process is very complex and incorporates a number of mechanisms

  7. [An experimental study of the wear behavior of dental feldspathic glass-ceramic and lithium disilicate glass-ceramic].

    Science.gov (United States)

    Tian, Bei-min; Zhang, Shao-feng; He, Lin; Guo, Jia-wen; Yu, Jin-tao; Wu, Xiao-hong

    2013-11-01

    To investigate the tribology characteristics of two ceramic materials in vitro:feldspathic glass-ceramic (veneer porcelain) and lithium disilicate glass-ceramic (heat-pressed ceramic), and to evaluate the wear resistance of different ceramic materials from the dynamic chewing perspective. Wear tests were performed in simulated oral environment with stainless steel ball antagonists (r = 3 mm), veneer porcelain (CERAMCO 3) and heat-pressed ceramic (IPS e.max Press HT type) in the chewing simulator. The tribological tests were carried out under artificial saliva lubrication condition in room temperature with a vertical load of 10 N for 1.2×10(6) cycles (f = 1.5 Hz, uniform circular motion, revolving speed = 90 r/min, radius = 0.5 mm). The wear volumes were measured using three-dimensional profiling, and surface microscopic morphology were observed using scanning electron microscopy at time point of 200 000, 400 000, 600 000, 800 000, 1 000 000, and 1 200 000 cycles. In a simulated oral environment, the wear rates of veneer porcelain were (0.001 20 ± 0.00 018) , (0.000 10 ± 0.000 03) , (0.000 50 ± 0.000 05), (0.000 10 ± 0.000 02) , (0.004 10 ± 0.000 38) , and (0.019 00 ± 0.003 53) (×10(-4) mm(3)/cycles) at 200 000, 400 000, 600 000, 800 000, 1 000 000, 1 200 000 cycles. The wear rates of heat-pressed ceramic were (0.139 50 ± 0.030 94), (0.124 40 ± 0.031 20), (0.054 80 ± 0.005 38), (0.038 80 ± 0.006 10), (0.011 10 ± 0.003 75), (0.198 90 ± 0.045 80) (×10(-4) mm(3)/cycles) at 200 000, 400 000, 600 000, 800 000, 1 000 000, 1 200 000 cycles. Three stages were observed in the wear loss process of the two materials: running-in stage, steady wear stage and severe wear stage. In running-in and steady wear stage, the shallow wear tracks of veneer porcelain were produced by the fatigue effect.While in severe wear stage, the wear tracks turned into ploughing. In running-in stage, the surface of heat-pressed ceramic was characterized by dense and shallow ploughing

  8. Effect of heat input on microstructure, wear and friction behavior of (wt.-%) 50FeCrC-20FeW-30FeB coating on AISI 1020 produced by using PTA welding.

    Science.gov (United States)

    Özel, Cihan; Gürgenç, Turan

    2018-01-01

    In this study, AISI 1020 steel surface was coated in different heat inputs with (wt.-%) 50FeCrC-20FeW-30FeB powder mixture by using plasma transferred arc (PTA) welding method. The microstructure of the coated samples were investigated by using optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDS). The hardness was measured with micro hardness test device. The dry sliding wear and friction coefficient properties were determined using a block-on-disk type wear test device. Wear tests were performed at 19.62 N, 39.24 N, 58.86 N load and the sliding distance of 900 m. The results were shown that different microstructures formed due to the heat input change. The highest average micro hardness value was measured at 1217 HV on sample coated with low heat input. It was determined that the wear resistance decreased with increasing heat input.

  9. Effect of in-situ TiC particulate on the wear resistance of spray-deposited 7075 Al matrix composite

    International Nuclear Information System (INIS)

    Wang Feng; Liu Huimin; Yang Bin

    2005-01-01

    TiC reinforced 7075 Al matrix composites have been fabricated by a melt in-situ reaction spray deposition. The microstructures of spray-deposited alloys were studied using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The dry sliding wear behavior of the alloys was investigated using a pin-on-disc machine under four loads, namely 8.9, 17.8, 26.7 and 35.6 N. It has been found that the wear behavior of the alloys was dependent on the TiC content in the microstructure and the applied load. At a lower load (8.9 N), with increasing TiC content, the wear rate of the alloy was decreased. At a higher loads (26.7, 35.6 N), a spray-deposited 7075 Al alloy exhibited superior wear resistance to the 7075/TiC composites

  10. Wear behavior of contacting between thin film coating on SKD11 ball and 304 stainless steel disk

    Directory of Open Access Journals (Sweden)

    Sriprasird, J.

    2007-11-01

    Full Text Available Wear is a well known problem in metal stamping die, especially on the die working with stainless steel workpiece, in which wear rate is severe. This research considered various types of material coating on tool surface which were regularly practised in modern stamping industry due to the ability to increase wear resistance. The model study of friction "Ball-on-disk" technique was employed throughout this work. The disk was made from stainless steel austenitic grade (SUS304. The ball was made from cold work tool steel, SKD11 (JIS and was hardened to 60±2 HRC. Ball surface conditions selected for this work were non-coated, coated by TiC-CVD, TiCN (TiC/TiCN/TiN Multilayer-CVD and TiCN (TiN/TiCN Double layer-PVD, and treated by VC-TD. Tests were carried out without lubricant. The results show that the coating film and the surface treatment has no effect on the friction coefficient but it can reduce wear rate by 64.1-99.7% at contact pressure condition less than 1,100 MPa. At the higher level of contact pressure, only 2 types of coating, TiCN (Multilayer-CVD and TiC-CVD, can reduce wear rate. The other two, which are TiCN (Double layer-PVD coating film and a surface treatment by VC-TD process, on the contrary increase the rate of wear significantly. This is due to delamination of coating film at high contact pressure. The coating particles of high hardness accelerate wear phenomenon on the tool surface. Therefore, proper selection of tool surface condition depends on level of contact pressure generated in the process.

  11. Controlling wear failure of graphite-like carbon film in aqueous environment: Two feasible approaches

    International Nuclear Information System (INIS)

    Wang Yongxin; Wang Liping; Xue Qunji

    2011-01-01

    Friction and wear behaviors of graphite-like carbon (GLC) films in aqueous environment were investigated by a reciprocating sliding tribo-meter with ball-on-disc contact. Film structures and wear scars were studied by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and a non-contact 3D surface profiler. A comprehensive wear model of the GLC film in aqueous environment was established, and two feasible approaches to control critical factor to the corresponding wear failure were discussed. Results showed that wear loss of GLC films in aqueous environment was characterized by micro-plough and local delamination. Due to the significant material loss, local delamination of films was critical to wear failure of GLC film in aqueous environment if the film was not prepared properly. The initiation and propagation of micro-cracks within whole films closely related to the occurrence of the films delamination from the interface between interlayer and substrate. The increase of film density by adjusting the deposition condition would significantly reduce the film delamination from substrate, meanwhile, fabricating a proper interlayer between substrate and GLC films to prevent the penetration of water molecules into the interface between interlayer and substrate could effectively eliminate the delamination.

  12. Investigation of Wear Behavior of Aluminum Matrix Composite Reinforced by Al2O3 and Produced by Hot Pressing Process

    Directory of Open Access Journals (Sweden)

    Halil ARIK

    2017-12-01

    Full Text Available In this study, Al powder produced by gas atomization technique has 72.06 µm average particle size and 99 % purity was mixed with as a reinforcement Al2O3 has 99.52% purity and 45 submicron particle size in a high energy ball mill for two hours. In order to obtain disk samples with 30 mm diameter and 6 mm thick mixed powders, after the characterization of particle size and morphology, were compacted in a single action press. Compaction process were carried out from mixed powders by hot pressing at 200 MPa pressure and 550 °C temperature for two hours. Then microstructural analysis, hardness and density measurements of powder metal composite parts were performed. After, the characterization of samples abrasion wear tests were performed according to ASTM-G99-05 by using TRIBOMETER T10/20 ball-on-disk abrasive wearing device. After the abrasive wear test of aluminum and composite powder metal parts produced under the identical test parameters, test results were compared and effect of Al2O3 on the wear properties of composite materials was exhibited. The test results showed that the composite parts have 62 % extra harness and better abrasion wear performance according to aluminum powder metal parts produced and tested under the identical conditions

  13. Microstructure and wear behavior of laser cladding VC–Cr7C3 ceramic coating on steel substrate

    International Nuclear Information System (INIS)

    Wu, Qianlin; Li, Wenge; Zhong, Ning; Gang, Wu; Haishan, Wang

    2013-01-01

    Highlights: ► The VC–Cr 7 C 3 coating on steel substrate was in situ produced by laser cladding. ► The distribution of VC–Cr 7 C 3 phase decreased gradually from the top of the coating. ► The laser cladding achieved a high hardness of the order of 1000 HV. ► The wear resistance of the coating was 4 times that of the steel substrate. - Abstract: To enhance the wear resistance of mechanical components, laser cladding has been applied to deposit in situ VC–Cr 7 C 3 ceramic coating on steel substrate using a pre-placed powder consisting of vanadium, carbon and high-carbon ferrochrome. The laser cladding samples were subjected to various microstructure examinations, microhardness and wear tests. The results showed that defect-free coating with metallurgical joint to the steel substrate was obtained. The quantity of VC–Cr 7 C 3 particles gradually increased from the bottom to the top of the coating. The VC particles in nanometer were observed within the coating. Average hardness of the coating up to 1050 HV was significantly higher than that of the substrate 150 HV. Wear tests indicated the wear resistance of the clad coating was 4 times that of the steel substrate

  14. FRICTION TORQUE IN THE SLIDE BEARINGS

    Directory of Open Access Journals (Sweden)

    BONDARENKO L. N.

    2016-09-01

    Full Text Available Summary. Problem statement. Until now slide bearings are used widely in engineering. But the calculation is made on obsolete method that is based on undetermined parameters such as wear of the bearing shell. It is accepted in the literature that if the shaft and liner material are homogeneous, the workpiece surface are cylindrical as they wear and contact between them occurs at all points contact arc. Research objective. The purpose of this study is determine a friction torque in the slide bearings of power-basis parameters. Conclusions. Since the friction is primarily responsible for wear of cinematic pairs “pin – liner” and “pivot – liner” slide bearings. It is shown that the friction torquesof angles wrap, that are obtained by the formulas and given in literature, are not only qualitatively but also quantitatively, namely, the calculation by literature to the formulas the friction torques are proportional to the angle wrap and the calculation by improved formulas the friction torques are inversely proportional to the angle wrap due to the reduction the normal pressure. Underreporting friction torque at large angle wrap is between 40 and 15 %. The difference in the magnitude of friction torque in the run-in and run-out cinematic pairs with real method of machining is 2...3 %, which it is possible to declare of reducing the finish of contacting surface of slide bearings.

  15. TRIBOLOGICAL BEHAVIOURS OF ABS AND PA6 POLYMERMETAL SLIDING COMBINATIONS UNDER DRY FRICTION, WATER ABSORBED AND ELECTROPLATED CONDITIONS

    Directory of Open Access Journals (Sweden)

    MITHUN V. KULKARNI

    2016-01-01

    Full Text Available The friction and wear properties of polyamide 6 (PA6 and poly-Acrylonitrile Butadiene Styrene (ABS sliding against metal under dry sliding, water absorption and electroplated (EP conditions were studied by using a pin-ondisc tribometer. The effect of applied load and sliding speed on the tribological behaviours of the polymer–metal sliding combinations under dry sliding, water absorbed and EP conditions were also investigated. The worn surfaces were examined by using Scanning Electron Microscope (SEM. Experimental results showed that ABS samples under water absorbed conditions showed higher wear loss compared to normal samples and the EP samples had exhibited lower wear loss compared to the water absorbed samples. Similarly EP-PA6 samples exhibited excellent wear resistance when compared with EP-ABS samples. Further, it was observed that the frictional heat produced on account of sliding action had a significant effect on the tribological behaviours of samples under dry sliding and water absorbed conditions.

  16. Preparation and wear behavior of polymer matrix composites with an interpenetrating network structure derived from natural sponge

    International Nuclear Information System (INIS)

    Wang Tianchi; Zhou Tianle; Xiong Dangsheng

    2010-01-01

    Natural sponge was used as a template to produce carbon/epoxy resin and (carbon+silicon carbide)/epoxy resin composites with interpenetrating network structures. Carbon with a network structure was first obtained by pyrolysis of the natural sponge. The composites were then obtained by injecting epoxy resin and silicone resin into the carbon. Their microstructures and wear properties were analyzed. The results show that the natural structure of sponge controlled the interpenetrating network structures of the composites. The netlike carbon in the composites reduced the wear rate of the epoxy resin. Compared with the carbon/epoxy resin composite, the (carbon+silicon carbide)/epoxy resin composite shows better wear resistance.

  17. Wear and Friction Behavior of Stir Cast Al-TiB2 Metal Matrix Composites with Various Lubricants

    Directory of Open Access Journals (Sweden)

    S. Poria

    2016-12-01

    Full Text Available Al- TiB2 metal matrix composites are fabricated using stir cast method and its tribological characterization is done using three different lubricants. Tribological studies are performed in a multi-tribotester using block-on-roller configuration under 25-75 N loads and 400-600 rpm rotational speeds. Four different weight percentages of TiB2 are considered in this study. Comparison between dry condition and lubricated conditions is gleaned to differentiate wear and friction characteristics and SEM images are taken to fortify them. Lubricated conditions yield large reduction in wear and friction compared to dry condition.

  18. Influence of contact conditions on vibration induced wear of metals

    International Nuclear Information System (INIS)

    Hofmann, P.J.; Schettler, T.; Wieling, N.; Steininger, D.A.

    1990-01-01

    Unfavourable design characteristics of nuclear power plant steam generators and heat exchangers in general may result in vibration induced tube wear. A systematic investigation was performed on the contact conditions which may appear between heat exchanger tubes and tube support structure and the influence of different parameters e.g., normal contact force, on the resulting steady state wear rates. It is concluded that not only are contact forces and sliding distances important in the wear process but also the type of relative motion has a decisive influence on the resulting wear rates. For a certain 'work rate', the wear rate caused by repeated impact motions between tube and tube support structure may be an order of magnitude higher than that caused by only sliding motion. This is the result of different operating wear mechanisms which are discussed in this paper. (orig.)

  19. Topographic and Electrochemical Ti6Al4V Alloy Surface Characterization in Dry and Wet Reciprocating Sliding

    Directory of Open Access Journals (Sweden)

    Z. Doni

    2013-09-01

    Full Text Available This present paper shows the behavior of functional integrity of the state Ti6Al4V alloy under reciprocating sliding wear conditions in acomparative way for two different counter materials, steel and ceramicballs in dry and corrosive environment (3.5% NaCl. The surface integrity analysis of the dry reciprocating wear tests was based on the evolution of The roughness parameters with the applied load. In the case of reciprocating wear tests in corrosive environment the surface integrity analysis was based on electrochemical parameters. Comparative analysis of the evolution of the roughness parameters with the applied load shows a higher stability of the Ti6Al4V/Al2O3 contact pair, while from the point of view of the electrochemical parameters the Tribological properties are worse than Ti6Al4V/steel ball contact pair.

  20. Predicting railway wheel wear under uncertainty of wear coefficient, using universal kriging

    International Nuclear Information System (INIS)

    Cremona, Marzia A.; Liu, Binbin; Hu, Yang; Bruni, Stefano; Lewis, Roger

    2016-01-01

    Railway wheel wear prediction is essential for reliability and optimal maintenance strategies of railway systems. Indeed, an accurate wear prediction can have both economic and safety implications. In this paper we propose a novel methodology, based on Archard's equation and a local contact model, to forecast the volume of material worn and the corresponding wheel remaining useful life (RUL). A universal kriging estimate of the wear coefficient is embedded in our method. Exploiting the dependence of wear coefficient measurements with similar contact pressure and sliding speed, we construct a continuous wear coefficient map that proves to be more informative than the ones currently available in the literature. Moreover, this approach leads to an uncertainty analysis on the wear coefficient. As a consequence, we are able to construct wear prediction intervals that provide reasonable guidelines in practice. - Highlights: • Wear prediction is of outmost importance for reliability of railway systems. • Wear coefficient is essential in prediction through Archard's equation. • A novel methodology is developed to predict wear and RUL. • Universal kriging is used for wear coefficient and uncertainty estimation. • A simulation study and a real case application are provided.

  1. The friction wear of electrolytic composite coatings

    International Nuclear Information System (INIS)

    Starosta, R.

    2002-01-01

    The article presents the results of investigation of wear of galvanic composite coatings Ni-Al 2 O 3 and Ni-41%Fe-Al 2 O 3 . The diameter of small parts of aluminium oxide received 0.5; 3; 5 μm. Investigations of friction sliding were effected on PT3 device at Technical University of Gdansk. Counter sample constituted a funnel made of steel NC6 (750 HV). Increase of wear coatings together with the rise of iron content in matrix is observed. The rise of sizes of ceramic particles caused decrease of wear of composite coatings, but rise of steel funnel wear. The friction coefficient increased after ceramic particle s were built in coatings. The best wear resistance characterized Ni-41%Fe-Al 2 O 3 coatings containing 2.2x10 6 mm -2 ceramic particles. (author)

  2. Effect of boron doping on the wear behavior of the growth and nucleation surfaces of micro- and nanocrystalline diamond films

    NARCIS (Netherlands)

    Buijnsters, J.G.; Tsigkourakos, M.C.; Hantschel, T.; Gomes, F.O.V.; Nuytten, T.; Favia, P.; Bender, H; Arstila, K.; Celis, JP; Vandervorst, W

    2016-01-01

    B-doped diamond has become the ultimate material for applications in the field of microelectromechanical systems (MEMS), which require both highly wear resistant and electrically conductive diamond films and microstructures. Despite the extensive research of the tribological properties of undoped

  3. Wear determination in braking systems by radioisotopes

    International Nuclear Information System (INIS)

    Spruch, W.

    1979-01-01

    Friction and wear behaviour of friction couples has been tested applying loads and sliding speeds. The determination was carried out by direct measurements of the lining material and by surface activation of the opposite material with protons. The application limits of several braking materials could be determined and compared

  4. Investigation of Wear Coefficient of Manganese Phosphate Coated Tool Steel

    Directory of Open Access Journals (Sweden)

    S. Ilaiyavel

    2013-03-01

    Full Text Available In recent years the properties of the coating in terms of wear resistance is of paramount importance in order to prevent the formation of severe damages. In this study, Wear coefficient of uncoated, Manganese Phosphate coated, Manganese Phosphate coated with oil lubricant, Heat treated Manganese Phosphate coated with oil lubricant on AISI D2 steels was investigated using Archard’s equation. The wear tests were performed in a pin on disk apparatus as per ASTM G-99 Standard. The volumetric wear loss and wear coefficient were evaluated through pin on disc test using a sliding velocity of 3.0 m/s under normal load of 40 N and controlled condition of temperature and humidity. Based on the results of the wear test, the Heat treated Manganese Phosphate with oil lubricant exhibited the lowest average wear coefficient and the lowest wear loss under 40 N load.

  5. Wear behavioral study of as cast and 7 hr homogenized Al25Mg2Si2Cu4Ni alloy at constant load

    Science.gov (United States)

    Harlapur, M. D.; Sondur, D. G.; Akkimardi, V. G.; Mallapur, D. G.

    2018-04-01

    In the current study, the wear behavior of as cast and 7 hr homogenized Al25Mg2Si2Cu4Ni alloy has been investigated. Microstructure, SEM and EDS results confirm the presence of different intermetallic and their effects on wear properties of Al25Mg2Si2Cu4Ni alloy in as cast as well as aged condition. Alloying main elements like Si, Cu, Mg and Ni partly dissolve in the primary α-Al matrix and to some amount present in the form of intermetallic phases. SEM structure of as cast alloy shows blocks of Mg2Si which is at random distributed in the aluminium matrix. Precipitates of Al2Cu in the form of Chinese script are also observed. Also `Q' phase (Al-Si-Cu-Mg) be distributed uniformly into the aluminium matrix. Few coarsened platelets of Ni are seen. In case of 7 hr homogenized samples blocks of Mg2Si get rounded at the corners, Platelets of Ni get fragmented and distributed uniformly in the aluminium matrix. Results show improved volumetric wear resistance and reduced coefficient of friction after homogenizing heat treatment.

  6. A comparative study of tribological characteristics of hydrogenated DLC film sliding against ceramic mating materials for helium applications

    Science.gov (United States)

    Wu, Daheng; Ren, Siming; Pu, Jibin; Lu, Zhibin; Zhang, Guangan; Wang, Liping

    2018-05-01

    The tribological behaviors of hydrogenated DLC film sliding against Al2O3, ZrO2, Si3N4 and WC mating balls have been comparatively investigated by a ball-on-disk tribometer at 150 °C under helium and air (RH = 6%) conditions. The results showed that the mating material influenced the friction and wear behavior remarkably in helium atmosphere, where the wear rates were in inversely proportional to the friction coefficients (COF) of those tribo-pairs. Compared to the tests in helium, the tribological performance of DLC film significantly improved in air. Scanning electron microscope (SEM) and Raman spectroscopy were performed to study the friction behavior and wear mechanism of the film under different conditions. It suggested that the severe abrasion was caused by the strong interaction between the tribo-pairs in helium atmosphere at 150 °C, whereas the sufficient passivation of the dangling bonds of carbon atoms at sliding interface by chemically active molecules, such as water and oxygen, dominated the ultralow friction under air condition. Meanwhile, Hertz analysis was used to further elucidate the frictional mechanism of DLC film under helium and air conditions. It showed that the coefficient of friction was consistent with the varied tendency of the contact radius, namely, higher friction coefficient corresponded to the larger contact radius, which was the same with the relationship between the wear rate and the contact pressure. All of the results made better understanding of the essential mechanism of hydrogenated DLC film sliding against different pairs, which were able to guide the further application of DLC film in the industrial fields of helium atmosphere.

  7. Wear of control rod cluster assemblies and of instrumentation thimbles: first results obtained with the vibrateau wear simulator

    International Nuclear Information System (INIS)

    Zbinden, M.; Hersant, D.

    1993-07-01

    Several REP components are affected by a particular sort of damage called impact/sliding wear. This kind of wear, originating from flow induced vibrations, affects loosely supported tubular structures. The main involved components are: - the RCCAs claddings and the guides tubes, - the instrumentation thimbles, - the fuel rods claddings, - the SG tubes. The R and D Division is concerned with studies aiming to understand and to master the phenomena leading to this wear. The MTC Branch is charged of the study of the wear itself. Tests are carried out on wear rigs to understand and to model wear mechanisms. The following work is related to the two first wear tests campaigns on the VIBRATEAU wear simulator: - a reproducibility test series in order to assess the spreading of the experimental results, - a comparative test series on surface treatments used to improve the components war resistance. (authors). 7 figs., 2 tabs., 4 refs

  8. Tooth wear

    OpenAIRE

    Tušek Ivan; Tušek Jasmina

    2014-01-01

    Tooth wear is the loss of dental hard tissue that was not caused by decay and represents a common clinical problem of modern man. In the etiology of dental hard tissue lesions there are three dominant mechanisms that may act synergistically or separately:friction (friction), which is caused by abrasion of exogenous, or attrition of endogenous origin, chemical dissolution of dental hard tissues caused by erosion, occlusal stress created by compression and flexion and tension that leads to toot...

  9. Processing and study of the wear and friction behaviour of discrete ...

    Indian Academy of Sciences (India)

    due to the increase in the braking energy, (3) at low sliding speeds (5, 10 m s−1), abrasive wear is the main wear ... tion materials, gas turbine thermal barrier coatings, armour ..... in a optimum level to balance both the wear loss and the stop-.

  10. Ultra-High Molecular Weight Polyethylene: Influence of the Chemical, Physical and Mechanical Properties on the Wear Behavior. A Review

    Directory of Open Access Journals (Sweden)

    Pierangiola Bracco

    2017-07-01

    Full Text Available Ultra-high molecular weight polyethylene (UHMWPE is the most common bearing material in total joint arthroplasty due to its unique combination of superior mechanical properties and wear resistance over other polymers. A great deal of research in recent decades has focused on further improving its performances, in order to provide durable implants in young and active patients. From “historical”, gamma-air sterilized polyethylenes, to the so-called first and second generation of highly crosslinked materials, a variety of different formulations have progressively appeared in the market. This paper reviews the structure–properties relationship of these materials, with a particular emphasis on the in vitro and in vivo wear performances, through an analysis of the existing literature.

  11. Effect of Nano and Micro Friction Modifier Based Lubricants on Wear behavior between Steel-Steel Contacts

    Directory of Open Access Journals (Sweden)

    S. Bhaumik

    2017-03-01

    Full Text Available The wear and surface morphology between steel (EN24, 22-24Rc-steel (EN 31, 58-60Rc contacts was investigated in presence of friction modifiers based (micro-graphite/nano particles- multi wall carbon nano tubes and zinc oxide mineral oil. Though a decrease in wear was observed (upto a certain concentration of nano friction modifiers but a weight-gain in pins after the tests was observed for all tests with ZnO nanoparticles while weight loss was observed in tests with multi wall carbon nano tubes and graphite particles based oil samples. Surface characterization of the worn surfaces showed more surface deteriorations in case of mineral oil (no friction modifiers and mineral oil with graphite as compared with nano particles/tubes based lubricants. The occurrence of a tribo film due to the deposition of nano particle and the formation of a modified layer on the pin surfaces are likely to be responsible for the reduction of coefficient of friction and better surface roughness. Apart from investigating the wear behaviour between two steel surfaces under micro and nano particles based lubricant and analysing the surfaces of the samples a part of the work was also focussed on the weight gain after tribo tests with ZnO nano particle additions.

  12. 3D Finite Element Modeling for Possible Creeping Behavior of Gas Hydrate-related Slipstream Submarine Slide, offshore Vancouver Island, Canada

    Science.gov (United States)

    LONG, S.; He, T.; Lan, K.; Spence, G.; Yelisetti, S.

    2017-12-01

    Natural gas hydrate-related submarine landslides have been identified on worldwide continental slope. Being a potential risk for marine environment and engineering projects, it has been a hot topic of hydrate research in recent decades. The study target is Slipstream submarine landslide, one of the slope failures on the frontal ridges of the Northern Cascadia accretionary margin, off Vancouver Island, Canada. The previous studies of P- & S-wave velocity structure based on OBS (Ocean Bottom Seismometer) data of SeaJade (Seafloor Earthquake Array - Japan Canada Cascadia Experiment) project indicated that there are two high concentration gas-hydrate layers within the ridge, one is at a depth of 100 mbsf (meter beneath the seafloor) with anomalous high P-wave velocities and the other is just above the prominent BSR (bottom-simulating reflector) at a depth of 265-275 mbsf. In this study we investigated the possible creeping behavior of gas hydrate layer to examine the critical instability of the ridge slope using the finite element method for self weight and additional stress (e.g., mega earthquake) conditions. The elastic and elasticoplasticity moduli of gas hydrate layer were obtained from laboratory measurements for different uniaxial pressure tests, which indicated that the sediments behave elastically for uniaxial pressures below 6 MPa, but elasticoplastically between 6-6.77 MPa. The modeled shear stress distribution indicated that the current sliding surface is more likely connected with the shallow high-velocity gas hydrate layer and sliding process related with gas hydrate starts from the toe of the slope and then progressively retreats to the place of current headwall, in a series of triangular blocks or wedges. Since the study area is in the earthquake belt, the large seismic acceleration will greatly affect the stress field and pore pressure distribution within the ridge, and the landslide is going to happen and supposedly at the shallow high-velocity gas

  13. Effect of heat treatment on residual stress and wear behaviors of the TiNi/Ti2Ni based laser cladding composite coatings

    Science.gov (United States)

    Tao, Yang-Feng; Li, Jun; Lv, Ying-Hao; Hu, Lie-Feng

    2017-12-01

    The TiNi/Ti2Ni based composite coatings reinforced by TiC and TiB2 were prepared on Ti6Al4V at different circumstance temperatures (25 °C, 400 °C, 600 °C, and 800 °C) by laser cladding, then were preserved for 3 h. Macromorphologies and microstructures of the coatings were examined through an optical microscope (OM), an X-ray diffractometer (XRD), a scanning electron microscope (SEM), and an energy dispersive spectrometer (EDS). Residual stresses along the depth direction of the coatings were measured by the nanoindentation method, and wear behaviors of the coatings were also investigated using an ultra-functional wear testing machine. Results showed that the coatings were mainly composed of TiNi/Ti2Ni as the matrix and TiC/TiB2 as the reinforcement. A small amount of Cr2Ti was formed in the coatings prepared at 400 °C and 600 °C. Besides that, Ti3Al was also observed in the coating prepared at 800 °C. The tensile stress existed in the coatings prepared at 25 °C, 400 °C and 600 °C when the coating prepared at 800 °C was regarded as the stress-free reference. The average residual stress in the surface of coating prepared at 25 °C reached the largest value of about 2.79 GPa and presented a decreasing tendency with increasing the circumstance temperature (1.03 GPa at 400 °C, 0.52 GPa at 600 °C, and 0 GPa at 800 °C). It revealed that the rise in circumstance temperature contributed to the reduction in cracking susceptibility in the laser cladding coating. However, the wear volumes of the coatings were increased with increasing the circumstance temperature (0.1912 mm3 at 25 °C, 0.2828 mm3 at 400 °C, 0.3732 mm3 at 600 °C, and 0.6073 mm3 at 800 °C) due to the weakening in strain-hardening effect and the reduction in reinforcement density. The wear mechanism of the coatings was transformed from the single brittle-debonding into the combination of micro-cutting and brittle-debonding when the circumstance temperature was changed from room temperature to

  14. Sliding vane geometry turbines

    Science.gov (United States)

    Sun, Harold Huimin; Zhang, Jizhong; Hu, Liangjun; Hanna, Dave R

    2014-12-30

    Various systems and methods are described for a variable geometry turbine. In one example, a turbine nozzle comprises a central axis and a nozzle vane. The nozzle vane includes a stationary vane and a sliding vane. The sliding vane is positioned to slide in a direction substantially tangent to an inner circumference of the turbine nozzle and in contact with the stationary vane.

  15. On the debris-level origins of adhesive wear.

    Science.gov (United States)

    Aghababaei, Ramin; Warner, Derek H; Molinari, Jean-François

    2017-07-25

    Every contacting surface inevitably experiences wear. Predicting the exact amount of material loss due to wear relies on empirical data and cannot be obtained from any physical model. Here, we analyze and quantify wear at the most fundamental level, i.e., wear debris particles. Our simulations show that the asperity junction size dictates the debris volume, revealing the origins of the long-standing hypothesized correlation between the wear volume and the real contact area. No correlation, however, is found between the debris volume and the normal applied force at the debris level. Alternatively, we show that the junction size controls the tangential force and sliding distance such that their product, i.e., the tangential work, is always proportional to the debris volume, with a proportionality constant of 1 over the junction shear strength. This study provides an estimation of the debris volume without any empirical factor, resulting in a wear coefficient of unity at the debris level. Discrepant microscopic and macroscopic wear observations and models are then contextualized on the basis of this understanding. This finding offers a way to characterize the wear volume in atomistic simulations and atomic force microscope wear experiments. It also provides a fundamental basis for predicting the wear coefficient for sliding rough contacts, given the statistics of junction clusters sizes.

  16. Effect of mating materials on wear properties of amorphous hydrogenated carbon (a-C:H coating and tetrahedral amorphous carbon (ta-C coating in base oil boundary lubrication condition

    Directory of Open Access Journals (Sweden)

    Xiang Li

    2017-12-01

    Full Text Available In this study, wear behavior of amorphous hydrogenated carbon (a-C:H coating and tetrahedral amorphous carbon (ta-C coating when sliding against various mating materials in base oil boundary lubrication condition is comparatively investigated to find out the optimal combinations of DLC/mating material and corresponding wear mechanism of both DLC coating. Tribological tests were performed in a cylinder-on-disc tribometer, Field Emission Scanning Electron Microscopy, Raman spectroscopy is used for characterization of ta-C and a-C:H worn surface. The results show that the specific wear rate of ta-C coating increases along with the hardness and roughness of mating material increases, while the specific wear rate of a-C:H coating increases together with an increment in the ID/IG ratio. It is concluded that for ta-C coating, local stress concentration-induced microfracture is the main wear mechanism in relative high wear scenario, along with minor graphitization-induced wear which prevails in low wear scenario. On the other hand, a-C:H coating showed that simultaneous generation and removal of the graphitized layer on the contact surface is the predominant wear mechanism.

  17. A study on wear behaviour of Al/6101/graphite composites

    Directory of Open Access Journals (Sweden)

    Pardeep Sharma

    2017-03-01

    Full Text Available The current research work scrutinizes aluminium alloy 6101-graphite composites for their mechanical and tribological behaviour in dry sliding environments. The orthodox liquid casting technique had been used for the manufacturing of composite materials and imperilled to T6 heat treatment. The content of reinforcement particles was taken as 0, 4, 8, 12 and 16 wt.% of graphite to ascertain it is prospective as self-lubricating reinforcement in sliding wear environments. Hardness, tensile strength and flexural strength of cast Al6101 metal matrix and manufactured composites were evaluated. Hardness, tensile strength and flexural strength decreases with increasing volume fraction of graphite reinforcement as compared to cast Al6101 metal matrix. Wear tests were performed on pin on disc apparatus to assess the tribological behaviour of composites and to determine the optimum volume fraction of graphite for its minimum wear rate. Wear rate reduces with increase in graphite volume fraction and minimum wear rate was attained at 4 wt.% graphite. The wear was found to decrease with increase in sliding distance. The average co-efficient of friction also reduces with graphite addition and its minimum value was found to be at 4 wt.% graphite. The worn surfaces of wear specimens were studied through scanning electron microscopy. The occurrence of 4 wt.% of graphite reinforcement in the composites can reveal loftier wear possessions as compared to cast Al6101 metal matrix.

  18. Biotribological evaluation of artificial disc arthroplasty devices: influence of loading and kinematic patterns during in vitro wear simulation

    Science.gov (United States)

    Yue, James J.; Garcia, Rolando; Basson, Janet; Schwiesau, Jens; Fritz, Bernhard; Blömer, Wilhelm

    2008-01-01

    Wear simulation is an essential pre-clinical method to predict the mid- and long-term clinical wear behavior of newly introduced devices for total disc arthroplasty. The main requirement of a suitable method for spinal wear simulation has to be the ability to distinguish between design concepts and allow for a direct comparison of predicate devices. The objective of our study was to investigate the influence of loading and kinematic patterns based on two different protocols for spinal wear simulation (ISO/FDIS 18192-1 (2006) and ASTM F2423-05). In vitro wear simulation was performed with six activ® L lumbar artificial disc devices (Aesculap Tuttlingen, Germany). The applied kinematic pattern of movement was multidirectional for ISO (elliptic track) and unidirectional with a curvilinear shape for ASTM. Testing was done for 10 million cycles in the ISO loading mode and afterwards with the same specimens for 5 million cycles according to the ASTM protocol with a customized six-station servohydraulic spinal wear simulator (EndoLab Thansau, Germany). Gravimetrical and geometrical wear assessment, a slide track analysis correlated to an optical surface characterization, and an estimation of particle size and morphology were performed. The gravimetric wear rate for the first 10 million cycles was ISOinitial = 2.7 ± 0.3 mg/million cycles. During the ASTM test period (10–15 million cycles) a gravimetric wear rate of 0.14 ± 0.06 mg/million cycles was estimated. The wear rates between the ISO and ASTM driven simulations differ substantially (approximately 20-fold) and statistical analysis demonstrates a significant difference (p < 0.001) between the test groups. The main explanation of divergency between ISO and ASTM driven wear simulations is the multidirectional pattern of movement described in the ISO document resulting in a cross-shear stress on the polyethylene material. Due to previous retrieval observations, it seems to be very unlikely that a lumbar

  19. Wear of liquid nitrogen-cooled 440C bearing steels in an oxygen environment

    Science.gov (United States)

    Chaudhuri, Dilip K.; Verma, Ravi

    1988-01-01

    This paper presents up-to-date findings of the research being conducted to understand the mechanism of sliding wear in unlubricated 440C bearing steels under oxidative conditions. A sliding wear test rig has been designed and built with a cylinder-on-flat geometry. The equipment is capable of testing specimens under high axial loads and sliding speeds in a simulated LOX environment. Samples of 440C steel, quenched and tempered to a hardness of Rc 56, were tested under a load of 890 N and a sliding speed of 2.05 m/sec for total sliding distances of up to 5.54 km. Flash temperatures during these tests were measured with an IR camera and a fast digital recorder. Microstructural and microanalytical data from the worn surfaces and the debris particles are analyzed extensively, along with wear rates, flash temperatures, surface profiles, hardnesses, and residual stresses, in the context of oxidation and wear theories.

  20. On results of measurement and method of behavior analysis for land slide protection wall in excavation works for main building foundation of No.2 plant in Kashiwazaki-Kariwa Nuclear Power Station, Tokyo Electric Power Co., Inc

    International Nuclear Information System (INIS)

    Otsuki, Hideo; Tsuchi, Hiroyuki; Nishioka, Toshimichi

    1987-01-01

    Tokyo Electric Power Co. has been constructing the nuclear power station having 8 million kW capacity of seven BWR plants in the site of about 4.2 million m 2 in Niigata Prefecture. No.1 BWR plant of 1100 MWe output started the operation in September, 1985. As a rule, the important structures in nuclear power stations such as a reactor building and a turbine building are to be directly supported on bedrocks, and in this case, on the mudstone of Nishiyama strata. As this Nishiyama strata exists in large depth, the excavation works for the foundations of buildings are to be carried out by installing large scale land slide protection walls. In this report, among the excavation works for the main building foundation of No.2 plant, the results of examining the behavior of the land slide protection wall installed in soft rock ground based on the results of measurement of vertical excavation by land slide protection method and the techniques of its analysis are described. The geological features, the design of land slide protection walls, the measurement of the land slide protection walls and surrounding ground and the results, and the examination of the analysis methods by a beam model and FEM are reported. (Kako, I.)

  1. Design of earth slide prevention structure and results of analyzing its behavior in excavation work for main building foundation for No.4 plant in Kashiwazaki-Kariwa Nuclear Power Station

    International Nuclear Information System (INIS)

    Kuroda, Teruo; Shimazu, Masaomi; Terada, Kenji

    1990-01-01

    In the construction works for No.4 plant in Kashiwazaki-Kariwa Nuclear Power Station, Tokyo Electric Power Co., Inc., the excavation work using ground anchor type earth slide prevention structure of about 30 m height intended for soft rocks was carried out. In this report, the outline of the design of the earth slide prevention structure is described, and based on the results of measurement of the earth slide prevention structure and surrounding ground during the period of the excavation work, the effect that the underground continuous wall normally intersecting with the back of the earth slide prevention wall and structurally separated from it exerted to the deformation behavior of the earth slide prevention wall was examined, and the results are reported. The geological features of the site are explained. The excavation work is to excavate the site of +5 m level down to -26 m for the turbine building and to -38.15 m for the reactor building, and the quantity of earth to be excavated is 1.39 million m 3 . These valuable experiences are utilized for the design and construction of the following plants. (K.I.)

  2. Baseball and softball sliding injuries: incidence and correlates during one high school league varsity season.

    Science.gov (United States)

    Stovak, Mark; Parikh, Amit; Harvey, Anne T

    2012-11-01

    To estimate injury rates associated with sliding in high school baseball and softball. Prospective cohort study. Community high school athletic events. Ten high school varsity baseball and softball teams over 1 season. All sliding attempts were recorded during each game and recorded as headfirst, feetfirst, or diveback. Base type, playing surface, and field conditions were also noted. Injury exposure rates by game exposures and sliding/diveback exposures. Data were collected from 153 baseball games and 166 softball games. A greater proportion of slides were associated with injury in softball than in baseball (42.0 and 4.9 per 1000 slides; P softball (55 vs 35 per 1000 slides; P = 0.74). More powerful studies are required to determine whether efforts to prevent baseball sliding injuries at the high school level should focus on better education in sliding technique or changes in equipment. Softball players are vulnerable to injury when wearing inadequate protective sliding apparel.

  3. A mechanistic understanding of the wear coefficient: From single to multiple asperities contact

    Science.gov (United States)

    Frérot, Lucas; Aghababaei, Ramin; Molinari, Jean-François

    2018-05-01

    Sliding contact between solids leads to material detaching from their surfaces in the form of debris particles, a process known as wear. According to the well-known Archard wear model, the wear volume (i.e. the volume of detached particles) is proportional to the load and the sliding distance, while being inversely proportional to the hardness. The influence of other parameters are empirically merged into a factor, referred to as wear coefficient, which does not stem from any theoretical development, thus limiting the predictive capacity of the model. Based on a recent understanding of a critical length-scale controlling wear particle formation, we present two novel derivations of the wear coefficient: one based on Archard's interpretation of the wear coefficient as the probability of wear particle detachment and one that follows naturally from the up-scaling of asperity-level physics into a generic multi-asperity wear model. As a result, the variation of wear rate and wear coefficient are discussed in terms of the properties of the interface, surface roughness parameters and applied load for various rough contact situations. Both new wear interpretations are evaluated analytically and numerically, and recover some key features of wear observed in experiments. This work shines new light on the understanding of wear, potentially opening a pathway for calculating the wear coefficient from first principles.

  4. Development of aircraft brake materials. [evaluation of metal and ceramic materials in sliding tests simulation of aircraft braking

    Science.gov (United States)

    Ho, T. L.; Peterson, M. B.

    1974-01-01

    The requirements of brake materials were outlined and a survey made to select materials to meet the needs of high temperature brakes. A number of metals and ceramic materials were selected and evaluated in sliding tests which simulated aircraft braking. Nickel, molybdenum tungsten, Zr02, high temperature cements and carbons were tested. Additives were then incorporated into these materials to optimize their wear or strength behavior with particular emphasis on nickel and molybdenum base materials and a high temperature potassium silicate cement. Optimum materials were developed which improved wear behavior over conventional brake materials in the simulated test. The best materials are a nickel, aluminum oxide, lead tungstate composition containing graphite or molybdenum disulphite; a molybdenum base material containing LPA100 (an intermetallic compound of cobalt, molybdenum, and silicon); and a carbon material (P5).

  5. Development of in-Situ Al-Si/CuAl₂ Metal Matrix Composites: Microstructure, Hardness, and Wear Behavior.

    Science.gov (United States)

    Tash, Mahmoud M; Mahmoud, Essam R I

    2016-06-02

    In the present work, in-situ metal matrix composites were fabricated through squeeze casting. The copper particles were dispersed with different weight percentages (3%, 6%, 10%, and 15%) into Al-12% Si piston alloy. Also, heat treatments were performed at 380 °C and 450 °C for holding times of 6 and 18 h. The microstructures, X-ray diffractometer (XRD) pattern, hardness, and wear characteristics were evaluated. The results showed that these copper particles have reacted with the aluminum under all of the aforementioned processing conditions resulting in the formation of fine copper aluminide intermetallics. Most of the intermetallics were CuAl₂, while AlCu appeared in a small ratio. Additionally, these intermetallics were homogenously distributed within the alloy matrix with up to 6% Cu addition. The amounts of those intermetallics increased after performing heat treatment. Most of these intermetallics were CuAl₂ at 380 °C, while the Cu-rich intermetallics appeared at 450 °C. Increasing the holding time to 18 h, however, led to grain coarsening and resulted in the formation of some cracks. The hardness of the resulting composite materials was improved. The hardness value reached to about 170 HV after heat treating at 380 °C for 8 h. The wear resistance of the resulting composite materials was remarkably improved, especially at lower additions of Cu and at the lower heat treatment temperature.

  6. Development of in-Situ Al-Si/CuAl2 Metal Matrix Composites: Microstructure, Hardness, and Wear Behavior

    Directory of Open Access Journals (Sweden)

    Mahmoud M. Tash

    2016-06-01

    Full Text Available In the present work, in-situ metal matrix composites were fabricated through squeeze casting. The copper particles were dispersed with different weight percentages (3%, 6%, 10%, and 15% into Al-12% Si piston alloy. Also, heat treatments were performed at 380 °C and 450 °C for holding times of 6 and 18 h. The microstructures, X-ray diffractometer (XRD pattern, hardness, and wear characteristics were evaluated. The results showed that these copper particles have reacted with the aluminum under all of the aforementioned processing conditions resulting in the formation of fine copper aluminide intermetallics. Most of the intermetallics were CuAl2, while AlCu appeared in a small ratio. Additionally, these intermetallics were homogenously distributed within the alloy matrix with up to 6% Cu addition. The amounts of those intermetallics increased after performing heat treatment. Most of these intermetallics were CuAl2 at 380 °C, while the Cu-rich intermetallics appeared at 450 °C. Increasing the holding time to 18 h, however, led to grain coarsening and resulted in the formation of some cracks. The hardness of the resulting composite materials was improved. The hardness value reached to about 170 HV after heat treating at 380 °C for 8 h. The wear resistance of the resulting composite materials was remarkably improved, especially at lower additions of Cu and at the lower heat treatment temperature.

  7. Mechanical Properties and Wear Behavior of a Novel Composite of Acrylonitrile–Butadiene–Styrene Strengthened by Short Basalt Fiber

    Directory of Open Access Journals (Sweden)

    Mohammed Y. Abdellah

    2018-06-01

    Full Text Available Polymer matrix composites (PMC have a competitive and dominant role in a lot of industries, like aerospace and automobiles. Short basalt fiber (SBF is used to strengthen acrylonitrile–butadiene–styrene (ABS polymers as a composite. The composite material is fabricated using injection molding with a new technique to obtain a uniform distribution for the ABS matrix at an elevated temperature range from 140 °C to 240 °C. Four types of specimen were produced according to the mechanically mixed amounts of SBF, which were (5, 10, 15, 20 wt %. The produced material was tested for tension, hardness and impact to measure the enhancement of the mechanical properties of the ABS only and the ABS reinforced by SBF composite. Wear tests were carried out using a pin on disc at a velocity of 57.5 m/s at three normal loads of 5, 10 and 15 kN. Tensile strength increased with up to 5 wt % of SBF, then decreased with an increasing amount of SBF reinforcement, while surface hardness increased with increasing SBF. The impact strength was found to degrade with the whole increment of SBF. Wear resistance increased with the increasing SBF reinforcement amount at all applied normal loads.

  8. Microstructure and erosive wear behaviors of Ti6Al4V alloy treated by plasma Ni alloying

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.X.; Wu, H.R.; Shan, X.L.; Lin, N.M.; He, Z.Y., E-mail: tyuthzy@126.com; Liu, X.P.

    2016-12-01

    Graphical abstract: The Ni modified layers were prepared on the surface of Ti6Al4V substrate by the plasma surface alloying technique. The surface and cross-section morphology, element concentration and phase composition were investigated by thermal field emission scanning electron microscopy (SEM), and glow discharge optical emission spectroscopy (GDOES), X-ray diffraction (XRD), respectively. The cross-section nano-scale hardness of Ni modified layer was measured by nano indenter. The results showed that Ni modified layers exhibited triple layers structure and continuous gradient distribution of the concentration. From the surface to the matrix, they were 2 μm Ni deposition layer, 8 μm Ni-rich alloying layer including the phases of Ni{sub 3}Ti, NiTi, Ti{sub 2}Ni, AlNi{sub 3} and 24 μm Ni-poor alloying layer forming the solid solution of nickel. With increasing of the thickness of Ni modified layer, the microhardness increased first, reached the climax, then gradient decreased. The erosion tests were performed on the surface of the untreated and treated Ti6Al4V sample using MSE (Micro-slurry-jet Erosion) method. The experiment results showed that the wear rate of every layer showed different value, and the Ni-rich alloying layer was the lowest. The strengthening mechanism of Ni modified layer was also discussed. - Highlights: • The Ni modified layers were prepared by the plasma surface alloying technique. • Triple layers structure was prepared. • Using Micro-slurry-jet Erosion method. • The erosion rate of Ni modified layer experienced the process of descending first and then ascending. • Improvement of erosion resistance performance of Ni-rich alloying layer was prominent. The wear mechanism of Ni modified layer showed micro-cutting wearing. - Abstract: The Ni modified layers were prepared on the surface of Ti6Al4V substrate by the plasma surface alloying technique. The surface and cross-section morphology, element concentration and phase composition

  9. Increasing Wear Resistance of Titanium Alloys by Anode Plasma Electrolytic Saturation with Interstitial Elements

    Science.gov (United States)

    Belkin, P. N.; Kusmanov, S. A.; Dyakov, I. G.; Silkin, S. A.; Smirnov, A. A.

    2017-05-01

    In our previous studies, we have shown that anode plasma electrolytic saturation of titanium alloys with nitrogen and carbon can improve their tribological properties. Obtained structure containing oxide layer and solid solution of diffused element in titanium promotes the enhancement of running-in ability and the decrease in the wear rate in some special cases. In this paper, further investigations are reported regarding the tribological properties of alpha- and beta-titanium alloys in wear test against hardened steel (50 HRC) disk using pin-on-disk geometry and balls of Al2O3 (6.25 mm in diameter) or bearing steel (9.6 mm in diameter) with ball-on-plate one and normal load from 5 to 209 N. Reproducible results were obtained under testing samples treated by means of the plasma electrolytic nitriding (PEN) with the mechanical removal of the oxide layer. Friction coefficient of nitrided samples is 0.5-0.9 which is somewhat higher than that for untreated one (0.48-0.75) during dry sliding against Al2O3 ball. An increase in the sliding speed results in the polishing of nitrided samples and reduction of their wear rate by 60 times. This result is obtained for 5 min at 850 °C using PEN in electrolyte containing 5 wt.% ammonia and 10 wt.% ammonium chloride followed by quenching in solution. Optical microscope was employed to assist in the evaluation of the wear behavior. Sizes of wear tracks were measured by profilometer TR200.

  10. Comportamiento del hierro nodular austemperizado en condiciones de corrosión y desgaste // Behavior of austempered ductile iron under wear and corrosion conditions

    Directory of Open Access Journals (Sweden)

    L. Goyos Pérez

    1999-07-01

    Full Text Available Los hierros nodulares en general y los austemperizados en particular han sido usados con cada vez mayor frecuencia debido asus relevantes propiedades mecánicas en comparación con su costo.En el presente trabajo se valora el comportamiento del hierro nodular ante el trabajo en condiciones de desgaste y corrosión,luego de ser sometido a diferentes tratamientos de austemperizado.Fueron usados un hierro nodular aleado con níquel y molibdeno y otro no aleado. Ambos hierros fueron sometidos a diferentestratamientos de austemperización con mantenimientos isotérmicos a temperaturas entre 250°C y 425°C por tiempos entre 15 y180 minutos.Las muestras tratadas fueron sometidas a ensayos de desgaste por fricción en condiciones no lubricadas determinando laspendientes de desgaste uniforme para cada caso. La resistencia a la corrosión fue determinada mediante el métodopotenciométrico usando como medio el jugo de caña sintético.A partir de los resultados obtenidos se valora la influencia de los diferentes tratamientos sobre las propiedades estudiadas y sedeterminan los más efectivos desde el punto de vista técnico económico.Palabras claves: Hierro nodular, corrosión, desgaste, austemperizado.____________________________________________________________________________AbstractNodular irons and particularly austempered ductile iron has been used more and more due to their excellent mechanicalproperties in comparison with their cost.Presently work deals on behavior of nodular iron working under wear and corrosion conditions, after being submitted todifferent austempered treatments.A nodular iron alloyed with nickel and molybdenum were used as well as a not alloyed one. Both irons were treated underdifferent austempered treatment combinations using isothermal maintenance to temperatures between 250°C and 425°C andspending times between 15 and 180 minutes.Samples were submitted to non-lubricated wear using a “pin on disk” method evaluating the

  11. An in vitro investigation of human enamel wear by restorative dental materials

    International Nuclear Information System (INIS)

    Adachi, L.K.; Saiki, M.; De Campos, T.N.

    2001-01-01

    A radiometric method was applied to asses enamel wear by another enamel and by restorative materials. The radioactive enamel was submitted to wear in a machine which allows sliding motion of an antagonistic surface in contact with the radioactive enamel. The enamel wear was evaluated by measuring the beta-activity of 32 P transferred to water from this irradiated tooth. Results obtained indicated that dental porcelains cause pronounced enamel wear when compared with that provoked by another natural enamel or by resin materials. Resin materials caused less enamel wear than another natural enamel. Vickers microhardness data obtained for antagonistic materials showed a correlation with the wear caused to the enamel. (author)

  12. Probabilistic Analysis of Wear of Polymer Material used in Medical Implants

    Directory of Open Access Journals (Sweden)

    T. Goswami

    2016-05-01

    Full Text Available Probabilistic methods are applied to the study of fatigue wear of sliding surfaces. A variance of time to failure (to occurrence of maximum allowable wear depth is evaluated as a function of a mean wear rate of normal wear and a size of wear particles. A method of estimating probability of failure-free work during a certain time interval (reliability is presented. An effect of the bedding-in phase of wear on the reliability is taken into account. Experimental data for Ultra High Molecular Weight Polyethylene (UHMWPE cups of artificial hip implants is used to make numerical calculations.

  13. Elevated temperature wear of Al6061 and Al6061-20%Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Singh, J.; Alpas, A.T. [Univ. of Windsor, Ontario (Canada)

    1995-04-01

    Both current and potential applications of particulate reinforced aluminum alloys involve components which are required to operate under sliding contact conditions at elevated temperatures. Examples include brake rotors, piston and cylinder liners in automotive engines where operating temperatures can reach 0.5--0.8 of the melting temperature of the matrix alloy. For this reason, study of the high temperature wear resistance of aluminum alloys reinforced by Al{sub 2}O{sub 3} or SiC particles is important. These studies are also of interest for the problem of die wear during hot extrusion of aluminum matrix composites and to rationalize the process of frictional welding involved in joining of the composites. Although the room temperature tribological and mechanical behaviors of aluminum matrix composites have received considerable attention, their high temperature properties have only recently started being considered. It has been shown that Al-Si-Mg (A356) alloys with or without SiC particles show a transition from mild to severe wear when a critical temperature (at about 0.4 T{sub m}, where T{sub m} is the melting temperature of aluminum) is reached as a result of frictional heating under dry sliding conditions. In this work, high temperature wear of A16061 and A16061-20%Al{sub 2}O{sub 3} was studied at temperatures between 25--500 C. The microstructural changes that occurred during wear have been delineated in order to understand the wear mechanisms that operate at high temperatures.

  14. Effective lecture slides

    International Nuclear Information System (INIS)

    Lim, Jae Hoon

    1986-01-01

    Lawyers, with their constant opportunity for practice, show a talent for public oratory that few doctors can equal. However, the physician, despite his more modest and hesitant delivery, has one great advantage over the most experienced lawyer. He is allowed to use slides. Slides of good quality conceal defects in oratory and they make for a confident speaker and a contented audience. By contrast, smudged, complicated or ill prepared slides may draw attention to minor defects in delivery and make the audience inattentive.

  15. Tribological behavior of Ti-6Al-4V and Ti-6Al-7Nb Alloys for Total Hip Prosthesis

    Directory of Open Access Journals (Sweden)

    Mamoun Fellah

    2014-01-01

    Full Text Available The aim of the study is to evaluate the friction and wear behavior of high-strength alloys Ti-6Al-7Nb used in femoral stem and compare it with a Ti-6Al-4V alloy cylindrical bar corresponding to ISO 5832-3 part 3/01-07-199 standard. The tribological behavior was investigated by wear tests, using ball-on-disc and pin-on-disc tribometers. These tests consisted of measuring the weight loss and the friction coefficient of samples. The oscillating friction and wear tests have been carried out in ambient with oscillating tribotester in accordance with standards ISO 7148, ASTM G99-95a, and ASTM G133-95 under different conditions of normal loads (3, 6, and 10 N and sliding speeds (1, 15, and 25 mm·s−1. As counter pairs, a 100Cr6 steel ball with 10 mm in diameter was used. Results show that the two alloys had similar friction and wear performance, although their grain structures and compositions are different. Occurrence of large frictional occurred, is probably caused by formation and periodic, localized fracture of a transfer layer. Higher friction with larger fluctuation and higher wear rate was observed at the higher siding speed. The Ti-6Al-4V wear mechanism transforms from ploughing and peeling off wear at low sliding speed to plastic deformation and adhesive wear.

  16. 3D FEM Simulation of Flank Wear in Turning

    Science.gov (United States)

    Attanasio, Aldo; Ceretti, Elisabetta; Giardini, Claudio

    2011-05-01

    This work deals with tool wear simulation. Studying the influence of tool wear on tool life, tool substitution policy and influence on final part quality, surface integrity, cutting forces and power consumption it is important to reduce the global process costs. Adhesion, abrasion, erosion, diffusion, corrosion and fracture are some of the phenomena responsible of the tool wear depending on the selected cutting parameters: cutting velocity, feed rate, depth of cut, …. In some cases these wear mechanisms are described by analytical models as a function of process variables (temperature, pressure and sliding velocity along the cutting surface). These analytical models are suitable to be implemented in FEM codes and they can be utilized to simulate the tool wear. In the present paper a commercial 3D FEM software has been customized to simulate the tool wear during turning operations when cutting AISI 1045 carbon steel with uncoated tungsten carbide tip. The FEM software was improved by means of a suitable subroutine able to modify the tool geometry on the basis of the estimated tool wear as the simulation goes on. Since for the considered couple of tool-workpiece material the main phenomena generating wear are the abrasive and the diffusive ones, the tool wear model implemented into the subroutine was obtained as combination between the Usui's and the Takeyama and Murata's models. A comparison between experimental and simulated flank tool wear curves is reported demonstrating that it is possible to simulate the tool wear development.

  17. Ceramic-like wear behaviour of human dental enamel.

    Science.gov (United States)

    Arsecularatne, J A; Hoffman, M

    2012-04-01

    This paper reports a transmission electron microscopy (TEM) analysis of subsurfaces of enamel specimens following in vitro reciprocating wear tests with an enamel cusp sliding on a flat enamel specimen under hydrated conditions. The obtained results show that crack formation occurred in the wear scar subsurface. The path followed by these cracks seems to be dictated either by the histological structure of enamel or by the contact stress field. Moreover, the analysis of a set of enamel wear results obtained from the literature and application of fracture-based models, originally developed for ceramics, correlate well, confirming the similar wear processes taking place in these materials. This analysis also reveals a marked influence of coefficient of friction on the enamel wear rate: for a higher coefficient of friction value, enamel wear can be severe even under forces generated during normal operation of teeth. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Experimental investigations of the frictional and wear behavior of tungsten carbide cermet ball bearings under axial load in liquid sodium

    International Nuclear Information System (INIS)

    Kleefeldt, K.W.

    1976-01-01

    The paper describes part of the R and D work performed on ball bearings operated in a liquid sodium environment and tested under conditions which are felt to be representative for high precision mechanisms in LMFBR's. After a short introduction, mainly dealing with the experimental results of other authors, a description will be given of the test facility, the test procedure, the ball bearings and the basis for the selection of the materials. The paper covers the experimental phase, which has been carried out in two steps. In the first phase material screening tests demonstrated the tungsten-carbide-cobalt cermet to be superior to the other materials tested with respect to friction and wear. This material, therefore, was selected for a more detailed parameter test programme during phase 2. Up to now a series of tests have been performed with bearing load and speed as parameters, indicating that fatigue is the life limiting factor. It shows that a life-load relationship, similar to that known for conventional ball bearing technology, also seems appropriate for the test conditions and environment investigated here

  19. Tooth wear and wear investigations in dentistry.

    Science.gov (United States)

    Lee, A; He, L H; Lyons, K; Swain, M V

    2012-03-01

    Tooth wear has been recognised as a major problem in dentistry. Epidemiological studies have reported an increasing prevalence of tooth wear and general dental practitioners see a greater number of patients seeking treatment with worn dentition. Although the dental literature contains numerous publications related to management and rehabilitation of tooth wear of varying aetiologies, our understanding of the aetiology and pathogenesis of tooth wear is still limited. The wear behaviour of dental biomaterials has also been extensively researched to improve our understanding of the underlying mechanisms and for the development of restorative materials with good wear resistance. The complex nature of tooth wear indicates challenges for conducting in vitro and in vivo wear investigations and a clear correlation between in vitro and in vivo data has not been established. The objective was to critically review the peer reviewed English-language literature pertaining to prevalence and aetiology of tooth wear and wear investigations in dentistry identified through a Medline search engine combined with hand-searching of the relevant literature, covering the period between 1960 and 2011. © 2011 Blackwell Publishing Ltd.

  20. Surface flow in severe plastic deformation of metals by sliding

    International Nuclear Information System (INIS)

    Mahato, A; Yeung, H; Chandrasekar, S; Guo, Y

    2014-01-01

    An in situ study of flow in severe plastic deformation (SPD) of surfaces by sliding is described. The model system – a hard wedge sliding against a metal surface – is representative of surface conditioning processes typical of manufacturing, and sliding wear. By combining high speed imaging and image analysis, important characteristics of unconstrained plastic flow inherent to this system are highlighted. These characteristics include development of large plastic strains on the surface and in the subsurface by laminar type flow, unusual fluid-like flow with vortex formation and surface folding, and defect and particle generation. Preferred conditions, as well as undesirable regimes, for surface SPD are demarcated. Implications for surface conditioning in manufacturing, modeling of surface deformation and wear are discussed

  1. Mailing microscope slides

    Science.gov (United States)

    Many insects feed agriculturally important crops, trees, and ornamental plants and cause millions of dollars of damage annually. Identification for some of these require the preparation of a microscope slide for examination. There are times when a microscope slide may need to be sent away to a speci...

  2. Chaos control using sliding-mode theory

    International Nuclear Information System (INIS)

    Nazzal, Jamal M.; Natsheh, Ammar N.

    2007-01-01

    Chaos control means to design a controller that is able to mitigating or eliminating the chaos behavior of nonlinear systems that experiencing such phenomenon. In this paper, a nonlinear Sliding-Mode Controller (SMC) is presented. Two nonlinear chaotic systems are chosen to be our case study in this paper, the well known Chua's circuit and Lorenz system. The study shows the effectiveness of the designed nonlinear Sliding-Mode Controller

  3. Wear Response of Aluminium 6061 Composite Reinforced with Red Mud at Elevated Temperature

    Directory of Open Access Journals (Sweden)

    R. Dabral

    2017-09-01

    Full Text Available The present work is focused on the investigations on dry sliding wear behaviour of aluminium metal matrix composite at room and elevated temperature. Aluminium metal matrix composites reinforced with red mud are prepared by stir casting method. The experiments are planned using Taguchi technique. An orthogonal array, analysis of variance and signal to noise ratio are used to check the influence of wear parameters like temperature, percentage of reinforcement, mesh size, load, sliding distance and sliding speed on dry sliding wear of composites. The optimal testing parameters are found and their values are calculated which are then compared with predicted values. A reasonable agreement is found between predicted and actual values. The model prepared in the present work can be effectively used to predict the specific wear rate of the composites.

  4. CORROSION AND WEAR PROPERTIES OF MATERIALS USED FOR MINCED MEAT PRODUCTION

    DEFF Research Database (Denmark)

    Jellesen, Morten Stendahl; Hansen, Martin Otto Laver; Hilbert, Lisbeth Rischel

    2009-01-01

    measurements. Combined sliding wear and corrosion conditions have been simulated in laboratory using a block-on-ring setup allowing for electrochemical measurements. Detailed information concerning the mechanism of possible material degradation is provided by these results, together with microstructural...

  5. Effect of thermal treatments on the wear behaviour of duplex stainless steels

    International Nuclear Information System (INIS)

    Fargas, G; Mestra, A; Anglada, M; Mateo, A

    2009-01-01

    Duplex stainless steel (DSS) is a family of steels characterized by two-phase microstructure with similar percentages of ferrite (α) and austenite (γ).Their attractive combination of mechanical properties and corrosion resistance has increased its use in last decades in the marine and petrochemical industries. Nevertheless, an inappropriate heat treatment can induce the precipitation of secondary phases which affect directly their mechanical properties and corrosion resistance. There are few works dealing with the influence of heat treatments on wear behaviour of these steels in the literature. For instances, this paper aims to determine wear kinetic and sliding wear volume developed as a function of heat treatment conditions. Therefore, the samples were heat treated from 850 deg. C to 975 deg.C before sliding wear tests. These wear tests were carried out using ball on disk technique at constant sliding velocity and different sliding distances. Two methodologies were used to calculate the wear volume: weight loss and area measurement using a simplified contact model. Microstructural observations showed the presence of sigma phase for all studied conditions. The formation kinetics of this phase is faster at 875 deg. C and decrease at higher temperatures. Results related to wear showed that the hardness introduced due to the presence of sigma phase plays an important role on wear behaviour for this steel. It was observed also that wear rates decreased when increasing the percentage of sigma phase on the microstructure.

  6. Wear and Degradation Modes in Selected Vehicle Tribosystems

    OpenAIRE

    G. Pantazopoulos; A. Tsolakis; P. Psyllaki; A. Vazdirvanidis

    2015-01-01

    The wear and degradation mechanisms of two principle vehicle tribosystems are presented to elucidate the main causes of their premature failure. The first case study concerns the malfunction of an automotive cast iron pressure plate operated in an automobile clutch system. The second is related to the unexpected failure of a stainless steel brake disk of a high performance motorcycle. Both components are designed to function under sliding friction conditions that lead to the severe wear of co...

  7. Dynamic SEM wear studies of tungsten carbide cermets. [friction and wear experiments

    Science.gov (United States)

    Brainard, W. A.; Buckley, D. H.

    1975-01-01

    Dynamic friction and wear experiments were conducted in a scanning electron microscope. The wear behavior of pure tungsten carbide and composite with 6 and 15 weight percent cobalt binder was examined, and etching of the binder was done to selectively determine the role of the binder in the wear process. Dynamic experiments were conducted as the tungsten carbide (WC) and bonded WC cermet surfaces were transversed by a 50 micron radiused diamond stylus. These studies show that the predominant wear process in WC is fracture initiated by plastic deformation, and the wear of the etched cermets is similar to pure WC. The presence of the cobalt binder reduces both friction and wear. The cementing action of the cobalt reduces granular separation, and promotes a dense polished layer because of its low shear strength film-forming properties. The wear debris generated from unetched surface is approximately the same composition as the bulk.

  8. Endurance in Al Alloy Melts and Wear Resistance of Titanium Matrix Composite Shot-Sleeve for Aluminum Alloy Die-casting

    International Nuclear Information System (INIS)

    Choi, Bong-Jae; Kim, Young-Jig; Sung, Si-Young

    2012-01-01

    The main purpose of this study was to evaluate the endurance against Al alloy melts and wear resistance of an in-situ synthesized titanium matrix composite (TMC) sleeve for aluminum alloy die-casting. The conventional die-casting shot sleeve material was STD61 tool steel. TMCs have great thermal stability, wear and oxidation resistance. The in-situ reaction between Ti and B4C leads to two kinds of thermodynamically stable reinforcements, such as TiBw and TiCp. To evaluate the feasibility of the application to a TMCs diecasting shot sleeve, the interfacial reaction behavior was examined between Al alloys melts with TMCs and STD61 tool steel. The pin-on-disk type dry sliding wear test was also investigated for TMCs and STD61 tool steel.

  9. Delamination wear mechanism in gray cast irons

    International Nuclear Information System (INIS)

    Salehi, M.

    2000-01-01

    An investigation of the friction and sliding wear of gray cast iron against chromium plated cast irons was carried out on a newly constructed reciprocating friction and wear tester. The tests were the first to be done on the test rig under dry conditions and at the speed of 170 cm/min, and variable loads of 20-260 N for a duration of 15 min. to 3 hours. The gray cast iron surfaces worn by a process of plastic deformation at the subsurface, crack nucleation, and crack growth leading to formation of plate like debris and therefore the delamination theory applies. No evidence of adhesion was observed. This could be due to formation of oxides on the wear surface which prevent adhesion. channel type chromium plating ''picked'' up cast iron from the counter-body surfaces by mechanically trapping cast iron debris on and within the cracks. The removal of the plated chromium left a pitted surface on the cast iron

  10. Wear Resistant Amorphous and Nanocomposite Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Racek, O

    2008-03-26

    Glass forming materials (critical cooling rate <10{sup 4}K.s{sup -1}) are promising for their high corrosion and wear resistance. During rapid cooling, the materials form an amorphous structure that transforms to nanocrystalline during a process of devitrification. High hardness (HV 1690) can be achieved through a controlled crystallization. Thermal spray process has been used to apply coatings, which preserves the amorphous/nanocomposite structure due to a high cooling rate of the feedstock particles during the impact on a substrate. Wear properties have been studied with respect to process conditions and feedstock material properties. Application specific properties such as sliding wear resistance have been correlated with laboratory tests based on instrumented indentation and scratch tests.

  11. Study on microstructure and high temperature wear resistance of laser cladded nuclear valve clack

    International Nuclear Information System (INIS)

    Zhang Chunliang; Chen Zichen

    2002-01-01

    Laser cladding of Co-base alloy on the nuclear valve-sealing surface are performed with a 5 kW CO 2 transverse flowing laser. The microstructure and the high temperature impact-slide wear resistance of the laser cladded coating and the plasma cladded coating are studied. The results show that the microstructure, the dilution rate and the high temperature impact-slide wear resistance of the laser cladded coating have obvious advantages over the spurt cladding processing

  12. Fatigue and Wear in Rolling and Sliding Contacts

    DEFF Research Database (Denmark)

    Janakiraman, Shravan

    bearing supports the main shaft, which connects the rotor to thegearbox. The main bearing is a rolling element bearing containing sphericalrolling elements. The loads on a main bearings are very high, which leads toa lubrication regime called elastohydrodynamic lubrication (EHL). Under theEHL regime...... to increase the film thickness, so as to ensure there is no contactbetween the roller and the raceway. Under lower loads (loads less than EHLloads) it has been observed that axial grooves help to increase the film thicknessat certain optimum operating conditions. It is believed that these groovesact...... the filmthickness. They might improve the film thickness at certain optimum runningconditions, but it is tough to ascertain what those conditions are.The main bearings also undergo rolling contact fatigue failure. The main bearingsexperience premature fatigue failure in both onshore and offshore windturbines...

  13. A Method of the Wear Prognosis of Sliding Bearings

    Directory of Open Access Journals (Sweden)

    Miszczak Andrzej

    2014-12-01

    Full Text Available Rozwazania przedstawione w niniejszej pracy obejmuja komputerowa analize prognozy zuzycia łozyska slizgowego z wykorzystaniem rozwiazan równan rekurencyjnych oraz danych eksperymentalnych.

  14. 3D Finite Element Modeling of Sliding Wear

    Science.gov (United States)

    2013-12-01

    In these pictures one can clearly see the slipper rotation. In the second picture, one can also see what is called the “slipper fire ” due to the...Design Manual for Dual Rail, Narrow Gage, and Monorail Rocket Sleds. Technical Report, Test Track Division, 6585th Test Group, Holloman AFB, New

  15. Severe wear behaviour of alumina balls sliding against diamond ...

    Indian Academy of Sciences (India)

    study, alumina ball was chosen as the counter body material to show better performance of the ... Tribology is a relatively new science that considers ... The science is applied in ... for example, in hip prosthesis, instead of existing alumina.

  16. Friction and wear of some ferrous-base metallic glasses

    Science.gov (United States)

    Miyoshi, K.; Buckley, D. H.

    1984-01-01

    Sliding friction experiments, X-ray photoelectron spectroscopy (XPS) analysis, and electron microscopy and diffraction studies were conducted with ferrous base metallic glasses (amorphous alloys) in contact with aluminium oxide at temperatures to 750 C in a vacuum. Sliding friction experiments were also conducted in argon and air atmospheres. The results of the investigation indicate that the coefficient of friction increases with increasing temperature to 350 C in vacuum. The increase in friction is due to an increase in adhesion resulting from surface segregation of boric oxide and/or silicon oxide to the surface of the foil. Above 500 C the coefficient of friction decreased rapidly. The decrease correlates with the segregation of boron nitride to the surface. Contaminants can come from the bulk of the material to the surface upon heating and impart boric oxide and/or silicon oxide at 350 C and boron nitride above 500 C. The segregation of contaminants is responsible for the friction behavior. The amorphous alloys have superior wear resistance to crystalline 304 stainless steel. The relative concentrations of the various constituents at the surfaces of the amorphous alloys are very different from the nominal bulk compositions.

  17. Effect of gamma irradiation on the friction and wear of ultrahigh molecular weight polyethylene

    Science.gov (United States)

    Jones, W. R.; Hady, W. F.; Crugnola, A.

    1981-01-01

    The effect of sterilization gamma irradiation on the friction and wear properties of ultrahigh molecular weight polyethylene (UHMWPE) sliding against stainless steel 316L in dry air at 23 C is investigated, the results to be used in the development of artificial joints which are to surgically replace diseased human joints. A pin-on-disk sliding friction apparatus is used, a constant sliding speed in the range 0.061-0.27 m/s is maintained, a normal load of 1 kgf is applied with dead weight, and the irradiation dose levels are: 0, 2.5, and 5.0 Mrad. Wear and friction data and conditions for each of the ten tests are summarized, and include: (1) wear volume as a function of the sliding distance for the irradiation levels, (2) incremental wear rate, and (3) coefficient of friction as a function of the sliding distance. It is shown that (1) the friction and wear properties of UHMWPE are not significantly changed by the irradiation doses of 2.5 and 5.0 Mrad, (2) the irradiation increases the amount of insoluble gel as well as the amount of low molecular weight material, and (3) after run-in the wear rate is either steady or gradually decreases as a function of the sliding distance.

  18. Effects of Deep Cryogenic Treatment on the Wear Resistance and Mechanical Properties of AISI H13 Hot-Work Tool Steel

    Science.gov (United States)

    Çiçek, Adem; Kara, Fuat; Kıvak, Turgay; Ekici, Ergün; Uygur, İlyas

    2015-11-01

    In this study, a number of wear and tensile tests were performed to elucidate the effects of deep cryogenic treatment on the wear behavior and mechanical properties (hardness and tensile strength) of AISI H13 tool steel. In accordance with this purpose, three different heat treatments (conventional heat treatment (CHT), deep cryogenic treatment (DCT), and deep cryogenic treatment and tempering (DCTT)) were applied to tool steel samples. DCT and DCTT samples were held in nitrogen gas at -145 °C for 24 h. Wear tests were conducted on a dry pin-on-disk device using two loads of 60 and 80 N, two sliding velocities of 0.8 and 1 m/s, and a wear distance of 1000 m. All test results showed that DCT improved the adhesive wear resistance and mechanical properties of AISI H13 steel. The formation of small-sized and uniformly distributed carbide particles and the transformation of retained austenite to martensite played an important role in the improvements in the wear resistance and mechanical properties. After cleavage fracture, the surfaces of all samples were characterized by the cracking of primary carbides, while the DCT and DCTT samples displayed microvoid formation by decohesion of the fine carbides precipitated during the cryo-tempering process.

  19. XPS analysis of the effect of fillers on PTFE transfer film development in sliding contacts

    Science.gov (United States)

    Blanchet, T. A.; Kennedy, F. E.; Jayne, D. T.

    1993-01-01

    The development of transfer films atop steel counterfaces in contact with unfilled and bronze-filled PTFE has been studied using X-ray photoelectron spectroscopy. The sliding apparatus was contained within the vacuum of the analytical system, so the effects of the native oxide, hydrocarbon, and adsorbed gaseous surface layers of the steel upon the PTFE transfer behavior could be studied in situ. For both the filled and the unfilled PTFE, cleaner surfaces promoted greater amounts of transfer. Metal fluorides, which formed at the transfer film/counterface interface, were found solely in cases where the native oxide had been removed to expose the metallic surface prior to sliding. These fluorides also were found at clean metal/PTFE interfaces formed in the absence of frictional contact. A fraction of these fluorides resulted from irradiation damage inherent in XPS analysis. PTFE transfer films were found to build up with repeated sliding passes, by a process in which strands of transfer filled in the remaining counterface area. Under these reported test conditions, the transfer process is not expected to continue atop previously deposited transfer films. The bronze-filled composite generated greater amounts of transfer than the unfilled PTFE. The results are discussed relative to the observed increase in wear resistance imparted to PTFE by a broad range of inorganic fillers.

  20. Superlubric sliding of graphene nanoflakes on graphene.

    Science.gov (United States)

    Feng, Xiaofeng; Kwon, Sangku; Park, Jeong Young; Salmeron, Miquel

    2013-02-26

    The lubricating properties of graphite and graphene have been intensely studied by sliding a frictional force microscope tip against them to understand the origin of the observed low friction. In contrast, the relative motion of free graphene layers remains poorly understood. Here we report a study of the sliding behavior of graphene nanoflakes (GNFs) on a graphene surface. Using scanning tunneling microscopy, we found that the GNFs show facile translational and rotational motions between commensurate initial and final states at temperatures as low as 5 K. The motion is initiated by a tip-induced transition of the flakes from a commensurate to an incommensurate registry with the underlying graphene layer (the superlubric state), followed by rapid sliding until another commensurate position is reached. Counterintuitively, the average sliding distance of the flakes is larger at 5 K than at 77 K, indicating that thermal fluctuations are likely to trigger their transitions from superlubric back to commensurate ground states.

  1. A new methodology for predictive tool wear

    Science.gov (United States)

    Kim, Won-Sik

    An empirical approach to tool wear, which requires a series of machining tests for each combination of insert and work material, has been a standard practice for industries since early part of the twentieth century. With many varieties of inserts and work materials available for machining, the empirical approach is too experiment-intensive that the demand for the development of a model-based approach is increasing. With a model-based approach, the developed wear equation can be extended without additional machining experiments. The main idea is that the temperatures on the primary wear areas are increasing such that the physical properties of the tool material degrade substantially and consequently tool wear increases. Dissolution and abrasion are identified to be the main mechanisms for tool wear. Flank wear is predominantly a phenomenon of abrasion as evident by the presence of a scoring mark on the flank surface. Based on this statement, it is reasonable to expect that the flank-wear rate would increase with the content of hard inclusions. However, experimental flank wear results did not necessary correspond to the content of cementite phase present in the steels. Hence, other phenomena are believed to significantly affect wear behavior under certain conditions. When the cutting temperature in the flank interface is subjected to high enough temperatures, pearlitic structure austenizes. During the formation of a new austenitic phase, the existing carbon is dissolved into the ferrite matrix, which will reduce the abrasive action. To verify the austenitic transformation, turning tests were conducted with plain carbon steels. The machined surface areas are imaged using X-ray diffraction the Scanning Electron Microscope (SEM) and the Transmission Electron Microscope (TEM). On the other hand, crater wear occurs as a result of dissolution wear and abrasive wear. To verify the wear mechanisms of crater wear, various coating inserts as well as uncoated inserts were

  2. Mechanics of slide dams

    International Nuclear Information System (INIS)

    Young, G.A.

    1970-01-01

    Studies which promote the use of nuclear energy for peaceful projects in engineering are sponsored by the Atomic Energy Commission under the Plowshare program. Specific projects being considered include the construction of harbors, canals, and dams. Of these projects, perhaps the most difficult to accomplish will be the latter. This paper which is in two parts considers the problems which are associated with the construction of slide dams with nuclear explosives. It examines first the characteristics of conventional earth and rock-fill dams which are based upon proven techniques developed after many years of experience. The characteristics of natural landslide dams are also briefly considered to identify potential problems that must be overcome by slide dam construction techniques. Second, the mechanics of slide dams as determined from small-scale laboratory studies are presented. It is concluded that slide dams can be constructed and that small-scale field tests and additional laboratory studies are justified. (author)

  3. Mechanics of slide dams

    Energy Technology Data Exchange (ETDEWEB)

    Young, G A [Engineering, Agbabian-Jacobsen Associates, Los Angeles (United States)

    1970-05-15

    Studies which promote the use of nuclear energy for peaceful projects in engineering are sponsored by the Atomic Energy Commission under the Plowshare program. Specific projects being considered include the construction of harbors, canals, and dams. Of these projects, perhaps the most difficult to accomplish will be the latter. This paper which is in two parts considers the problems which are associated with the construction of slide dams with nuclear explosives. It examines first the characteristics of conventional earth and rock-fill dams which are based upon proven techniques developed after many years of experience. The characteristics of natural landslide dams are also briefly considered to identify potential problems that must be overcome by slide dam construction techniques. Second, the mechanics of slide dams as determined from small-scale laboratory studies are presented. It is concluded that slide dams can be constructed and that small-scale field tests and additional laboratory studies are justified. (author)

  4. Tribological Behavior of TiC/a-C : H-Coated and Uncoated Steels Sliding Against Phenol-Formaldehyde Composite Reinforced with PTFE and Glass Fibers

    NARCIS (Netherlands)

    Shen, J.T.; Pei, Y.T.; Hosson, J.Th.M. De

    2013-01-01

    Tribological experiments on phenol-formaldehyde composite reinforced with polytetrafluoroethylene (PTFE) and glass fibers were performed against 100Cr6 steel and TiC/a-C:H thin film-coated 100Cr6 steel. In both cases, the coefficient of friction increases with increasing sliding distance until a

  5. Sliding mode control and observation

    CERN Document Server

    Shtessel, Yuri; Fridman, Leonid; Levant, Arie

    2014-01-01

    The sliding mode control methodology has proven effective in dealing with complex dynamical systems affected by disturbances, uncertainties and unmodeled dynamics. Robust control technology based on this methodology has been applied to many real-world problems, especially in the areas of aerospace control, electric power systems, electromechanical systems, and robotics. Sliding Mode Control and Observation represents the first textbook that starts with classical sliding mode control techniques and progresses toward newly developed higher-order sliding mode control and observation algorithms and their applications. The present volume addresses a range of sliding mode control issues, including: *Conventional sliding mode controller and observer design *Second-order sliding mode controllers and differentiators *Frequency domain analysis of conventional and second-order sliding mode controllers *Higher-order sliding mode controllers and differentiators *Higher-order sliding mode observers *Sliding mode disturbanc...

  6. Carbon-Phenolic Cages for High-Speed Bearings. Part 1 - Friction and Wear Response of Phenolic Composite Impregnated with a Multiply-Alkylated Cyclopentane (MAC) Lubricant and MoS2 Solid Lubricant

    National Research Council Canada - National Science Library

    Forster, Nelson

    2003-01-01

    .... This portion covers characterization of flat panel specimens using thermal conductivity, tensile strength, coefficient of thermal expansion measurement, and friction and wear testing in a sliding contact...

  7. Theoretical-experimental analysis of the fretting/impact wear in fuel rods

    International Nuclear Information System (INIS)

    Pecos, Luis F.

    2001-01-01

    Nuclear power plant fuel elements are subjected to flow induced vibrations. A consequence of these vibrations is impact/fretting wear in fuel rods or sliding shoes. Because of the difficulties to assert the mechanism of impact/fretting wear phenomenon it is necessary to use semiempirical formulations in order to predict the wear rate of the components. The results of a series of experiments with Zr-4 specimens are presented in this work. A parameter called 'work-rate' was used to normalize the wear rates and interpret the results in terms of wear coefficient. (author) [es

  8. Wear Behavior of Cold Pressed and Sintered Al2O3/TiC/CaF2Al2O3/TiC Laminated Ceramic Composite

    Institute of Scientific and Technical Information of China (English)

    Xuefeng YANG; Jian CHENG; Peilong SONG; Shouren WANG; Liying YANG; Yanjun WANG; Ken MAO

    2013-01-01

    A novel laminated Al2O3/TiC/CaF2-Al2O3/TiC sandwich ceramic composite was fabricated through cold pressing and sintering to achieve better anti-wear performance,such as low friction coefficient and low wear rate.Al2O3/TiC/CaF2 and Al2O3/TiC composites were alternatively built layer-by-layer to obtain a sandwich structure.Solid lubricant CaF2 was added evenly into the Al2O3/TiC/CaF2 layer to reduce the friction and wear.Al2O3/TiC ceramic was also cold pressed and sintered for comparison.Friction analysis of the two ceramics was then conducted via a wear-and-tear machine.Worn surface and surface compositions were examined by scanning electron microscopy and energy dispersion spectrum,respectively.Results showed that the laminated Al2O3/TiC/CaF2-Al2O3/TiC sandwich ceramic composite has lower friction coefficient and lower wear rate than those of Al2O3/TiC ceramic alone because of the addition of CaF2 into the laminated Al2O3/TiC/CaF2-Al2O3/TiC sandwich ceramic composite.Under the friction load,the tiny CaF2 particles were scraped from the Al2O3/TiC/CaF2 layer and spread on friction pairs before falling off into micropits.This process formed a smooth,self-lubricating film,which led to better anti-wear properties.Adhesive wear is the main wear mechanism of Al2O3/TiC/CaF2 layer and abrasive wear is the main wear mechanism of Al2O3/TiC layer.

  9. Tribological Behavior of Plasma-Sprayed Al2O3-20 wt.%TiO2 Coating

    Science.gov (United States)

    Cui, Shiyu; Miao, Qiang; Liang, Wenping; Zhang, Zhigang; Xu, Yi; Ren, Beilei

    2017-05-01

    Al2O3-20 wt.% TiO2 ceramic coatings were deposited on the surface of Grade D steel by plasma spraying of commercially available powders. The phases and the microstructures of the coatings were investigated by x-ray diffraction and scanning electron microscopy, respectively. The Al2O3-20 wt.% TiO2 composite coating exhibited a typical inter-lamellar structure consisting of the γ-Al2O3 and the Al2TiO5 phases. The dry sliding wear behavior of the coating was examined at 20 °C using a ball-on-disk wear tester. The plasma-sprayed coating showed a low wear rate ( 4.5 × 10-6 mm3 N-1 m-1), which was matrix ( 283.3 × 10-6 mm3 N-1 m-1), under a load of 15 N. In addition, the tribological behavior of the plasma-sprayed coating was analyzed by examining the microstructure after the wear tests. It was found that delamination of the Al2TiO5 phase was the main cause of the wear during the sliding wear tests. A suitable model was used to simulate the wear mechanism of the coating.

  10. A study of microstructure and wear behaviour of TiB2/Al metal matrix composites

    Directory of Open Access Journals (Sweden)

    A. Sreenivasan

    Full Text Available The present paper deals with the study of microstructure and wear characteristics of TiB2 reinforced aluminium metal matrix composites (MMCs. Matrix alloys with 5, 10 and 15% of TiB2 were made using stir casting technique. Effect of sliding velocity on the wear behaviour and tribo-chemistry of the worn surfaces of both matrix and composites sliding against a EN24 steel disc has been investigated under dry conditions. A pin-on-disc wear testing machine was used to find the wear rate, in which EN24 steel disc was used as the counter face, loads of 10-60N in steps of 10N and speeds of 100, 200, 300, 400 and 500 rpm were employed. The results showed that the wear rate was increased with an increase in load and sliding speed for both the materials. However, a lower wear rate was obtained for MMCs when compared to the matrix alloys. The wear transition from slight to severe was presented at the critical applied loads. The transition loads for the MMCs were much higher than that of the matrix alloy. The transition loads were increased with increase in TiB2 and the same was decreased with the increase of sliding speeds. The SEM and EDS analyses were undertaken to demonstrate the effect of TiB2 particles on the wear mechanism for each conditions.

  11. Wear Characterization of Aluminium/Basalt Fiber Reinforced Metal Matrix Composites - A Novel Material

    Directory of Open Access Journals (Sweden)

    P. Amuthakkannan

    2017-06-01

    Full Text Available Aluminum alloy based metal matrix composite participate have a wider applications in wear resistance applications. Attempt made in current study is that, basalt fiber reinforced aluminum metal matrix composite have been prepared using stir casting method. Different weight percentage of basalt fiber reinforced with Al (6061 metal matrix composites are used to study the wear resistance of the composites. For wear study, percentage of reinforcement, normal load and sliding velocity are the considered as important parameters. To study the effect of basalt fiber reinforcement on the dry sliding wear of Al6061 alloy composites the Pin On wear tester is used. Initially hardness of the composites was tested, it was found that increasing reinforcement in the composite hardness value of the composites also increased. Based on the Grey relation analysis (GRA the effects of wear resistance of the composites were studied.

  12. Friction and wear study of diamond-like carbon gradient coatings on Ti6Al4V substrate prepared by plasma source ion implant-ion beam enhanced deposition

    International Nuclear Information System (INIS)

    Jiang, Shuwen; Jiang Bin; Li Yan; Li Yanrong; Yin Guangfu; Zheng Changqiong

    2004-01-01

    DLC gradient coatings had been deposited on Ti6Al4V alloy substrate by plasma source ion implantation-ion beam enhanced deposition method and their friction and wear behavior sliding against ultra high molecular weight polyethylene counterpart were investigated. The results showed that DLC gradient coated Ti6Al4V had low friction coefficient, which reduced 24, 14 and 10% compared with non-coated Ti6Al4V alloy under dry sliding, lubrication of bovine serum and 0.9% NaCl solution, respectively. DLC gradient coated Ti6Al4V showed significantly improved wear resistance, the wear rate was about half of non-coated Ti6Al4V alloy. The wear of ultra high molecular weight polyethylene counterpart was also reduced. High adhesion to Ti6Al4V substrate of DLC gradient coatings and surface structure played important roles in improved tribological performance, serious oxidative wear was eliminated when DLC gradient coating was applied to the Ti6Al4V alloy

  13. Frictional sliding in layered rock: laboratory-scale experiments

    International Nuclear Information System (INIS)

    Buescher, B.J.; Perry, K.E. Jr.; Epstein, J.S.

    1996-09-01

    The work is part of the rock mechanics effort for the Yucca Mountain Site Characterization Program. The laboratory-scale experiments are intended to provide high quality data on the mechanical behavior of jointed structures that can be used to validate complex numerical models for rock-mass behavior. Frictional sliding between simulated rock joints was studied using phase shifting moire interferometry. A model, constructed from stacks of machined and sandblasted granite plates, contained a central hole bore normal to the place so that frictional slip would be induced between the plates near the hole under compressive loading. Results show a clear evolution of slip with increasing load. Since the rock was not cycled through loading- unloading, the quantitative differences between the three data sets are probably due to a ''wearing-in'' effect. The highly variable spatial frequency of the data is probably due to the large grain size of the granite and the stochastic frictional processes. An unusual feature of the evolution of slip with increasing load is that as the load gets larger, some plates seem to return to a null position. Figs, 6 refs

  14. Effects of Plasma ZrN Metallurgy and Shot Peening Duplex Treatment on Fretting Wear and Fretting Fatigue Behavior of Ti6Al4V Alloy.

    Science.gov (United States)

    Tang, Jingang; Liu, Daoxin; Zhang, Xiaohua; Du, Dongxing; Yu, Shouming

    2016-03-23

    A metallurgical zirconium nitride (ZrN) layer was fabricated using glow metallurgy using nitriding with zirconiuming prior treatment of the Ti6Al4V alloy. The microstructure, composition and microhardness of the corresponding layer were studied. The influence of this treatment on fretting wear (FW) and fretting fatigue (FF) behavior of the Ti6Al4V alloy was studied. The composite layer consisted of an 8-μm-thick ZrN compound layer and a 50-μm-thick nitrogen-rich Zr-Ti solid solution layer. The surface microhardness of the composite layer is 1775 HK 0.1 . A gradient in cross-sectional microhardness distribution exists in the layer. The plasma ZrN metallurgical layer improves the FW resistance of the Ti6Al4V alloy, but reduces the base FF resistance. This occurs because the improvement in surface hardness results in lowering of the toughness and increasing in the notch sensitivity. Compared with shot peening treatment, plasma ZrN metallurgy and shot peening composite treatment improves the FW resistance and enhances the FF resistance of the Ti6Al4V alloy. This is attributed to the introduction of a compressive stress field. The combination of toughness, strength, FW resistance and fatigue resistance enhance the FF resistance for titanium alloy.

  15. Effects of Varying Epoch Lengths, Wear Time Algorithms, and Activity Cut-Points on Estimates of Child Sedentary Behavior and Physical Activity from Accelerometer Data.

    Science.gov (United States)

    Banda, Jorge A; Haydel, K Farish; Davila, Tania; Desai, Manisha; Bryson, Susan; Haskell, William L; Matheson, Donna; Robinson, Thomas N

    2016-01-01

    To examine the effects of accelerometer epoch lengths, wear time (WT) algorithms, and activity cut-points on estimates of WT, sedentary behavior (SB), and physical activity (PA). 268 7-11 year-olds with BMI ≥ 85th percentile for age and sex wore accelerometers on their right hips for 4-7 days. Data were processed and analyzed at epoch lengths of 1-, 5-, 10-, 15-, 30-, and 60-seconds. For each epoch length, WT minutes/day was determined using three common WT algorithms, and minutes/day and percent time spent in SB, light (LPA), moderate (MPA), and vigorous (VPA) PA were determined using five common activity cut-points. ANOVA tested differences in WT, SB, LPA, MPA, VPA, and MVPA when using the different epoch lengths, WT algorithms, and activity cut-points. WT minutes/day varied significantly by epoch length when using the NHANES WT algorithm (p algorithms. Minutes/day and percent time spent in SB, LPA, MPA, VPA, and MVPA varied significantly by epoch length for all sets of activity cut-points tested with all three WT algorithms (all p algorithms (all p algorithms and activity cut-point definitions to match different epoch lengths may introduce significant errors. Estimates of SB and PA from studies that process and analyze data using different epoch lengths, WT algorithms, and/or activity cut-points are not comparable, potentially leading to very different results, interpretations, and conclusions, misleading research and public policy.

  16. Effect of solid lubricants on friction and wear behaviour of alloyed ...

    Indian Academy of Sciences (India)

    Friction and wear behaviour of MoS2, boric acid, graphite and TiO2 at four different sliding speeds (1.0, 1.5, 2.0, 2.5 m/s) has been compared with dry sliding condition. MoS2 and graphite show 30 to 50% reduction in mass loss compared to other lubricants at all sliding speeds. Friction coefficient reduces with increase in ...

  17. Effects of Surface Modification and Bulk Geometry on the Biotribological Behavior of Cross-Linked Polyethylene: Wear Testing and Finite Element Analysis.

    Science.gov (United States)

    Watanabe, Kenichi; Kyomoto, Masayuki; Saiga, Kenichi; Taketomi, Shuji; Inui, Hiroshi; Kadono, Yuho; Takatori, Yoshio; Tanaka, Sakae; Ishihara, Kazuhiko; Moro, Toru

    2015-01-01

    The wear and creep deformation resistances of polymeric orthopedic bearing materials are both important for extending their longevity. In this study, we evaluated the wear and creep deformation resistances, including backside damage, of different polyethylene (PE) materials, namely, conventional PE, cross-linked PE (CLPE), and poly(2-methacryloyloxyethyl phosphorylcholine)- (PMPC-) grafted CLPE, through wear tests and finite element analysis. The gravimetric and volumetric degrees of wear of disks (3 or 6 mm in thickness) of these materials against a cobalt-chromium-molybdenum alloy pin were examined using a multidirectional pin-on-disk tester. Cross-linking and PMPC grafting decreased the gravimetric wear of the PE disks significantly. The volumetric wear at the bearing surface and the volumetric penetration in the backside of the 3-mm thick PE disk were higher than those of the 6-mm thick PE disk, regardless of the bearing material. The geometrical changes induced in the PE disks consisted of creep, because the calculated internal von Mises stress at the bearing side of all disks and that at the backside of the 3-mm thick disks exceeded their actual yield strengths. A highly hydrated bearing surface layer, formed by PMPC grafting, and a cross-linking-strengthened substrate of adequate thickness are essential for increasing the wear and creep deformation resistances.

  18. Selected Landscape Plants. Slide Script.

    Science.gov (United States)

    McCann, Kevin

    This slide script, part of a series of slide scripts designed for use in vocational agriculture classes, deals with commercially important woody ornamental landscape plants. Included in the script are narrations for use with a total of 253 slides illustrating 92 different plants. Several slides are used to illustrate each plant: besides a view of…

  19. Modeling wear of cast Ti alloys.

    Science.gov (United States)

    Chan, Kwai S; Koike, Marie; Okabe, Toru

    2007-05-01

    The wear behavior of Ti-based alloys was analyzed by considering the elastic-plastic fracture of individual alloys in response to the relevant contact stress field. Using the contact stresses as the process driving force, wear was computed as the wear rate or volume loss as a function of hardness and tensile ductility for Ti-based cast alloys containing an alpha, alpha+beta or beta microstructure with or without the intermetallic precipitates. Model predictions indicated that wear of Ti alloys increases with increasing hardness but with decreasing fracture toughness or tensile ductility. The theoretical results are compared with experimental data to elucidate the roles of microstructure in wear and contrasted against those in grindability.

  20. Tool Wear Monitoring Using Time Series Analysis

    Science.gov (United States)

    Song, Dong Yeul; Ohara, Yasuhiro; Tamaki, Haruo; Suga, Masanobu

    A tool wear monitoring approach considering the nonlinear behavior of cutting mechanism caused by tool wear and/or localized chipping is proposed, and its effectiveness is verified through the cutting experiment and actual turning machining. Moreover, the variation in the surface roughness of the machined workpiece is also discussed using this approach. In this approach, the residual error between the actually measured vibration signal and the estimated signal obtained from the time series model corresponding to dynamic model of cutting is introduced as the feature of diagnosis. Consequently, it is found that the early tool wear state (i.e. flank wear under 40µm) can be monitored, and also the optimal tool exchange time and the tool wear state for actual turning machining can be judged by this change in the residual error. Moreover, the variation of surface roughness Pz in the range of 3 to 8µm can be estimated by the monitoring of the residual error.

  1. Tribological behavior at elevated temperature of multilayer TiCN/TiC/TiN hard coatings produced by chemical vapor deposition

    International Nuclear Information System (INIS)

    Bao Mingdong; Xu Xuebo; Zhang Haijun; Liu Xiaoping; Tian Linhai; Zeng Zhaoxin; Song Yubin

    2011-01-01

    Multilayer hard coatings of TiCN/TiC/TiN on high speed steel substrates were deposited using a chemical vapor deposition system. Evaluations of microstructure, wear morphology of coatings were characterized by scanning electron microscopy, and optical microscopy. Friction coefficient and wear rates of coatings were investigated using ball-on-disk tester sliding against a WC ball at a constant load of 20 N. Tribological behavior of the coatings at room and elevated temperature were discussed. Different changing tendency of friction coefficient were observed from ball-on-disc experiments. Results showed that the friction coefficient of coatings increased gradually to a highest value, then to a relatively constant value at room temperature dry sliding wear. The friction coefficient exhibited a reverse variation tendency at temperature of 550 °C. It got a higher value at the first sliding friction cycles. Then the value of friction coefficient decreased, suffered irregular oscillations and kept a relatively lower value with increasing sliding time. Reasons of the variation of friction coefficient with sliding time and wear mechanism were analyzed and discussed at room and elevated temperatures, respectively.

  2. Laser surface modification of Ti6Al4V-Cu for improved microhardness and wear resistance properties

    CSIR Research Space (South Africa)

    Erinosho, MF

    2017-06-01

    Full Text Available operating with linear reciprocating motion drive. The samples are rubbed against a ball-shaped upper specimen made of 9.5 mm diameter tungsten carbide ball. A load of 25 N, stroke length of 2 mm, oscillation frequency of 5 Hz and test duration of 1000... seconds were selected for the operation. The dry sliding wear tests were carried out according to the ASTM G133- 05 for determining the sliding wear of metals23. The wear loss was calculated from the length of the stroke, the width of the wear scar...

  3. Consideration of wear rates at high velocity

    Science.gov (United States)

    Hale, Chad S.

    The development of the research presented here is one in which high velocity relative sliding motion between two bodies in contact has been considered. Overall, the wear environment is truly three-dimensional. The attempt to characterize three-dimensional wear was not economically feasible because it must be analyzed at the micro-mechanical level to get results. Thus, an engineering approximation was carried out. This approximation was based on a metallographic study identifying the need to include viscoplasticity constitutive material models, coefficient of friction, relationships between the normal load and velocity, and the need to understand wave propagation. A sled test run at the Holloman High Speed Test Track (HHSTT) was considered for the determination of high velocity wear rates. In order to adequately characterize high velocity wear, it was necessary to formulate a numerical model that contained all of the physical events present. The experimental results of a VascoMax 300 maraging steel slipper sliding on an AISI 1080 steel rail during a January 2008 sled test mission were analyzed. During this rocket sled test, the slipper traveled 5,816 meters in 8.14 seconds and reached a maximum velocity of 1,530 m/s. This type of environment was never considered previously in terms of wear evaluation. Each of the features of the metallography were obtained through micro-mechanical experimental techniques. The byproduct of this analysis is that it is now possible to formulate a model that contains viscoplasticity, asperity collisions, temperature and frictional features. Based on the observations of the metallographic analysis, these necessary features have been included in the numerical model, which makes use of a time-dynamic program which follows the movement of a slipper during its experimental test run. The resulting velocity and pressure functions of time have been implemented in the explicit finite element code, ABAQUS. Two-dimensional, plane strain models

  4. Tribological behaviors of UHMWPE composites with different counter surface morphologies

    Science.gov (United States)

    Wang, Yanzhen; Yin, Zhongwei; Li, Hulin; Gao, Gengyuan

    2017-12-01

    The influence of counter surface morphologies on hybrid glass fiber (GF) and carbon fiber (CF) filled ultrahigh molecular weight polyethylene (UHMWPE) were studied under various contact pressure and sliding speed against GCr15 steel in dry condition. The goals were to investigate the tribological behavior of GF/CF/UHMWPE composite as a kind of water lubricated journal bearing material. The friction and wear behavior of composites were examined using a pin-on-disc tribometer. The morphologies of the worn surface were examined by scanning electron microscopy (SEM) and laser 3D micro-imaging and profile measurement. Generally, the wear rate and friction coefficient of composites increase as the increment of counter surface roughness. The friction coefficient increases firstly and then decrease with an increase in sliding speed and contact pressure for counterface with Ra=0.2 and 3.5 μm, while the friction coefficient decreased for counterface with Ra=0.6 μm.

  5. Dry-sliding tribological properties of ultrafine-grained Ti prepared by severe plastic deformation

    International Nuclear Information System (INIS)

    La Peiqing; Ma Jiqiang; Zhu, Yuntian T.; Yang Jun; Liu Weimin; Xue Qunji; Valiev, Ruslan Z.

    2005-01-01

    This paper reports the tribological properties of ultrafine-grained (UFG) Ti prepared by severe plastic deformation under dry sliding against AISI52100 steel in ambient environment and at varying load and sliding speed. Worn surfaces of the UFG Ti were examined with a scanning electron microscope and X-ray photoelectron spectroscope. It was found that the wear rate of the UFG Ti under dry sliding was of the magnitude of 10 -3 mm 3 m -1 , which is lower than that of the annealed coarse-grained (CG) Ti. The wear rate of the UFG Ti increased with the load, while it decreased with the sliding speed. The friction coefficient of the UFG Ti was in the range of 0.45-0.60, slightly lower than that of the CG Ti, and did not change with the load and sliding time after the initial transient period. The friction coefficient increased with increasing sliding speed to a maximum point and then decreased. The wear mechanism of the UFG Ti was micro-ploughing and delamination. The worn surfaces were covered by a TiO 2 layer. These results demonstrated that UFG structures improved the wear resistance but did not significantly affect the friction coefficient of Ti

  6. Study on Abrasive Wear of Brake Pad in the Large-megawatt Wind Turbine Brake Based on Deform Software

    Science.gov (United States)

    Zhang, Shengfang; Hao, Qiang; Sha, Zhihua; Yin, Jian; Ma, Fujian; Liu, Yu

    2017-12-01

    For the friction and wear issues of brake pads in the large-megawatt wind turbine brake during braking, this paper established the micro finite element model of abrasive wear by using Deform-2D software. Based on abrasive wear theory and considered the variation of the velocity and load in the micro friction and wear process, the Archard wear calculation model is developed. The influence rules of relative sliding velocity and friction coefficient in the brake pad and disc is analysed. The simulation results showed that as the relative sliding velocity increases, the wear will be more serious, while the larger friction coefficient lowered the contact pressure which released the wear of the brake pad.

  7. Carbon-Based Wear Coatings: Properties and Applications

    Science.gov (United States)

    Miyoshi, Kazuhisa

    2003-01-01

    The technical function of numerous engineering systems - such as vehicles, machines, and instruments - depends on the processes of motion and on the surface systems. Many processes in nature and technology depend on the motion and dynamic behavior of solids, liquids, and gases. Smart surface systems are essential because of the recent technological push toward higher speeds, loads, and operating temperatures; longer life; lighter weight and smaller size (including nanotechnology); and harsh environments in mechanical, mechatronic, and biomechanical systems. If proper attention is not given to surface systems, then vehicles, machines, instruments, and other technical systems could have short lives, consume excessive energy, experience breakdowns, result in liabilities, and fail to accomplish their missions. Surface systems strongly affect our national economy and our lifestyles. At the NASA Glenn Research Center, we believe that proper attention to surface systems, especially in education, research, and application, could lead to economic savings of between 1.3 and 1.6 percent of the gross domestic product. Wear coatings and surface systems continue to experience rapid growth as new coating and surface engineering technologies are discovered, more cost-effective coating and surface engineering solutions are developed, and marketers aggressively pursue, uncover, and exploit new applications for engineered surface systems in cutting tools and wear components. Wear coatings and smart surface systems have been used widely in industrial, consumer, automotive, aerospace, and biomedical applications. This presentation expresses the author's views of and insights into smart surface systems in wear coatings. A revolution is taking place in carbon science and technology. Diamond, an allotrope of carbon, joins graphite, fullerenes, and nanotubes as its major pure carbon structures. It has a unique combination of extreme properties: hardness and abrasion resistance; adhesion

  8. Rod cluster control assemblies and rod cluster control guide tubes: wear and drop time

    International Nuclear Information System (INIS)

    Zbinden, M.

    1997-01-01

    The wear of RCCAs and of RCC guide tubes is due to two quite different mechanisms and the remedies to apply for each case might lead to contradictory solutions: - the impact/sliding wear for the seldom moving RCCAs, namely the shutdown RCCAs, under flow-induced vibrations, - the axial sliding wear for the control rods subjected to the stepping movements ordered by the acting load. In this case the hydraulic sticking forces are those which produce an evolution of the surface states that may increase the drop time. The introduction, an historical survey of the encountered difficulties, is followed by short description of the components and then the paper presents contributions of EDF in the R and D field, which take place in two successive multi-annual projects. Lastly, some information is given about the recent evolutions and new problems as well for impact/sliding wear as for drop time under normal or seismic conditions. (author)

  9. Determination of a Wear Initiation Cycle by using a Contact Resistance Measurement in Nuclear Fuel Fretting

    International Nuclear Information System (INIS)

    Lee, Young Ho; Kim, Hyung Kyu

    2008-01-01

    In nuclear fuel fretting, the improving of the contact condition with a modified spring shape is a useful method for increasing the wear resistance of the nuclear fuel rod. This is because the fretting wear resistance between the fuel rod and grid spring is mainly affected by the grid spring shape rather than the environment, the contact modes, etc. In addition, the wear resistance is affected by the wear debris behavior between contact surfaces. So, it is expected that the wear initiation of each spring shape should be determined in order to evaluate a wear resistance. However, it is almost impossible to measure the wear behavior in contact surfaces on a real time basis because the contact surfaces are always hidden. Besides, the results of the worn surface observation after the fretting wear tests are restricted to archive the information on the wear debris behavior and the formation mechanism of the wear scar. In order to evaluate the wear behavior during the fretting wear tests, it is proposed that the contact resistance measurement is a useful method for examining the wear initiation cycle and modes. Generally, fretting wear damages are rapidly progressed by a localized plastic deformation between the contact surfaces, crack initiation and fracture of the deformed surface with a strain hardening difference between a surface and a subsurface and finally a detachment of wear debris. After this, wear debris is easily oxidized by frictional heat, test environment, etc. At this time, a small amount of electric current applied between the contact surfaces will be influenced by the wear debris, which could be an obstacle to an electric current flow. So, it is possible to archive the information on the wear behavior by measuring the contact resistance. In order to determine the wear initiation cycle during the fretting wear tests, in this study, fretting wear tests have been performed by applying a constant electric current in room temperature air

  10. Wear and Corrosion Properties of 316L-SiC Composite Coating Deposited by Cold Spray on Magnesium Alloy

    Science.gov (United States)

    Chen, Jie; Ma, Bing; Liu, Guang; Song, Hui; Wu, Jinming; Cui, Lang; Zheng, Ziyun

    2017-08-01

    In order to improve the wear and corrosion resistance of commonly used magnesium alloys, 316L stainless steel coating and 316L-SiC composite coating have been deposited directly on commercial AZ80 magnesium alloy using cold spraying technology (CS). The microstructure, hardness and bonding strength of as-sprayed coatings were studied. Their tribological properties sliding against Si3N4 and GCr15 steel under unlubricated conditions were evaluated by a ball-on-disk tribometer. Corrosion behaviors of coated samples were also evaluated and compared to that of uncoated magnesium alloy substrate in 3.5 wt.% NaCl solution by electrochemical measurements. Scanning electron microscopy was used to characterize the corresponding wear tracks and corroded surfaces to determine wear and corrosion mechanisms. The results showed that the as-sprayed coatings possessed higher microhardness and more excellent wear resistance than magnesium alloy substrate. Meanwhile, 316L and 316L-SiC coating also reduced the corrosion current density of magnesium alloy and the galvanic corrosion of the substrates was not observed after 200-h neutral salt spray exposure, which demonstrated that corrosion resistance of a magnesium alloy substrate could be greatly improved by cold-sprayed stainless steel-based coatings.

  11. Fretting-wear damage of heat exchanger tubes: a proposed damage criterion based on tube vibration response

    International Nuclear Information System (INIS)

    Yetisir, M.; McKerrow, E.; Pettigrew, M.J.

    1997-01-01

    A simple criterion is proposed to estimate fretting-wear damage in heat exchanger tubes with clearance supports. The criterion is based on parameters such as vibration frequency, mid-span vibration amplitude, span length, tube mass and an empirical wear coefficient. It is generally accepted that fretting-wear damage is proportional to a parameter called work-rate. Work-rate is a measure of the dynamic interaction between a vibrating tube and its supports. Due to the complexity of the impact-sliding behavior at the clearance-supports, work-rate calculations for heat exchanger tubes require specialized non-linear finite element codes. These codes include contact models for various clearance-support geometries. Such non-linear finite element analyses are complex, expensive and time consuming. The proposed criterion uses the results of linear vibration analysis (i.e., vibration frequency and mid-span vibration amplitude due to turbulence) and does not require a non-linear analysis. It can be used by non-specialists for a quick evaluation of the expected work-rate, and hence, the fretting-wear damage of heat exchanger tubes. The proposed criterion was obtained from an extensive parametric study that was conducted using a non-linear finite element program. It is shown that, by using the proposed work-rate criteria, work-rate can be estimated within a factor of two. This result, however, requires further testing with more complicated flow patterns. (author)

  12. Effect of medium on friction and wear properties of compacted graphite cast iron processed by biomimetic coupling laser remelting process

    International Nuclear Information System (INIS)

    Guo Qingchun; Zhou Hong; Wang Chengtao; Zhang Wei; Lin Pengyu; Sun Na; Ren Luquan

    2009-01-01

    Stimulated by the cuticles of soil animals, an attempt to improve the wear resistance of compact graphite cast iron (CGI) with biomimetic units on the surface was made by using a biomimetic coupled laser remelting process in air and various thicknesses water film, respectively. The microstructures of biomimetic units were examined by scanning electron microscope and X-ray diffraction was used to describe the microstructure and identify the phases in the melted zone. Microhardness was measured and the wear behaviors of biomimetic specimens as functions of different mediums as well as various water film thicknesses were investigated under dry sliding condition, respectively. The results indicated that the microstructure zones in the biomimetic specimens processed with water film are refined compared with that processed in air and had better wear resistance increased by 60%, the microhardness of biomimetic units has been improved significantly. The application of water film provided finer microstructures and much more regular grain shape in biomimetic units, which played a key role in improving the friction properties and wear resistance of CGI.

  13. Effect of medium on friction and wear properties of compacted graphite cast iron processed by biomimetic coupling laser remelting process

    Science.gov (United States)

    Guo, Qing-chun; Zhou, Hong; Wang, Cheng-tao; Zhang, Wei; Lin, Peng-yu; Sun, Na; Ren, Luquan

    2009-04-01

    Stimulated by the cuticles of soil animals, an attempt to improve the wear resistance of compact graphite cast iron (CGI) with biomimetic units on the surface was made by using a biomimetic coupled laser remelting process in air and various thicknesses water film, respectively. The microstructures of biomimetic units were examined by scanning electron microscope and X-ray diffraction was used to describe the microstructure and identify the phases in the melted zone. Microhardness was measured and the wear behaviors of biomimetic specimens as functions of different mediums as well as various water film thicknesses were investigated under dry sliding condition, respectively. The results indicated that the microstructure zones in the biomimetic specimens processed with water film are refined compared with that processed in air and had better wear resistance increased by 60%, the microhardness of biomimetic units has been improved significantly. The application of water film provided finer microstructures and much more regular grain shape in biomimetic units, which played a key role in improving the friction properties and wear resistance of CGI.

  14. Effects of Surface Modification and Bulk Geometry on the Biotribological Behavior of Cross-Linked Polyethylene: Wear Testing and Finite Element Analysis

    Directory of Open Access Journals (Sweden)

    Kenichi Watanabe

    2015-01-01

    phosphorylcholine- (PMPC- grafted CLPE, through wear tests and finite element analysis. The gravimetric and volumetric degrees of wear of disks (3 or 6 mm in thickness of these materials against a cobalt-chromium-molybdenum alloy pin were examined using a multidirectional pin-on-disk tester. Cross-linking and PMPC grafting decreased the gravimetric wear of the PE disks significantly. The volumetric wear at the bearing surface and the volumetric penetration in the backside of the 3-mm thick PE disk were higher than those of the 6-mm thick PE disk, regardless of the bearing material. The geometrical changes induced in the PE disks consisted of creep, because the calculated internal von Mises stress at the bearing side of all disks and that at the backside of the 3-mm thick disks exceeded their actual yield strengths. A highly hydrated bearing surface layer, formed by PMPC grafting, and a cross-linking-strengthened substrate of adequate thickness are essential for increasing the wear and creep deformation resistances.

  15. Experimental Investigation on Tool Wear Behavior and Cutting Temperature during Dry Machining of Carbon Steel SAE 1030 Using KC810 and KC910 Coated Inserts

    Directory of Open Access Journals (Sweden)

    Y. Tamerabet

    2018-03-01

    Full Text Available The removal of cutting fluids and lubrication in dry machining operations requires a good knowledge and full control of all the mechanisms that lead to tool damage. In order to optimize dry machining operations, it is necessary to clearly identify the wear patterns, determine the contact conditions and define the relationship between the contact parameters and the operating conditions. The idea is to choose optimal cutting conditions which lead to the best contact conditions limiting the triggering or aggravation of wear phenomena. The purpose of this paper is to determine the impact multilayer coatings and cutting parameters on tool wear and temperature at the tool-chip interface for two types of coated carbides (KC810 and KC910 Commercialized inserts during dry turning operation of carbon steel SAE 1030, in order to determine the ideal parameters and guarantee the best performances of the cutting tools. Cutting temperature, Crater and Flank wear have been systematically recorded in order to determine their influence on tool life time. To ensure the optimum choice of machining conditions; the TAGUCHI method associated to multi-factorial method were applied to plan the experiments. It has been noted that cutting speed was the most influential factor on temperature and wear evolution. We noted also that the KC810 insert was more suitable for machining of SAE 1030 Carbon Steel; where The best life time was registered (T=228 min. The KC810 inserts offer 30 min of additional machining time for the same work conditions.

  16. Wear-triggered self-healing behavior on the surface of nanocrystalline nickel aluminum bronze/Ti3SiC2 composites

    Science.gov (United States)

    Zhai, Wenzheng; Lu, Wenlong; Zhang, Po; Wang, Jian; Liu, Xiaojun; Zhou, Liping

    2018-04-01

    Self-healing can protect materials from diverse damages, but is intrinsically difficult in metals. This paper demonstrates a potential method through a simultaneous decomposition and oxidation of Ti3SiC2 to achieve healing of stress cracking on the surface of nickel aluminum bronze (NAB)/Ti3SiC2 nanocrystalline composites during fretting wear. At the finest nanocrystalline materials, a crack recovery would be attained at 76.5%. The repetitive fretting wear leads to a modest amount of 'flowability' of Ti3SiC2 toward the crack, facilitating crack recovery. Along with the wear-triggered self-healing, the NAB/Ti3SiC2 shows an improved tribological performance with the stable decreased friction torque due to the formation of lubrication TiO2 oxide.

  17. Abrasive Wear Resistance of Tool Steels Evaluated by the Pin-on-Disc Testing

    Science.gov (United States)

    Bressan, José Divo; Schopf, Roberto Alexandre

    2011-05-01

    Present work examines tool steels abrasion wear resistance and the abrasion mechanisms which are one main contributor to failure of tooling in metal forming industry. Tooling used in cutting and metal forming processes without lubrication fails due to this type of wear. In the workshop and engineering practice, it is common to relate wear resistance as function of material hardness only. However, there are others parameters which influences wear such as: fracture toughness, type of crystalline structure and the occurrence of hard precipitate in the metallic matrix and also its nature. In the present investigation, the wear mechanisms acting in tool steels were analyzed and, by normalized tests, wear resistance performance of nine different types of tool steels were evaluated by pin-on-disc testing. Conventional tool steels commonly used in tooling such as AISI H13 and AISI A2 were compared in relation to tool steels fabricated by sintering process such as Crucible CPM 3V, CPM 9V and M4 steels. Friction and wear testing were carried out in a pin-on-disc automated equipment which pin was tool steel and the counter-face was a abrasive disc of silicon carbide. Normal load of 5 N, sliding velocity of 0.45 m/s, total sliding distance of 3000 m and room temperature were employed. The wear rate was calculated by the Archard's equation and from the plotted graphs of pin cumulated volume loss versus sliding distance. Specimens were appropriately heat treated by quenching and three tempering cycles. Percentage of alloying elements, metallographic analyses of microstructure and Vickers microhardness of specimens were performed, analyzed and correlated with wear rate. The work is concluded by the presentation of a rank of tool steel wear rate, comparing the different tool steel abrasion wear resistance: the best tool steel wear resistance evaluated was the Crucible CPM 9V steel.

  18. Reciprocating wear in a steam environment

    Energy Technology Data Exchange (ETDEWEB)

    Brown, L.J.; Gee, M.G. [National Physical Laboratory, Teddington, Middlesex (United Kingdom)

    2010-07-01

    Tests to simulate the wear between sliding components in steam power plant have been performed using a low frequency wear apparatus at elevated temperatures under static load, at ambient pressure, in a steam environment. The apparatus was modified to accept a novel method of steam delivery. The materials tested were pre-exposed in a flowing steam furnace at temperature for either 500 or 3000 hours to provide some simulation of long term ageing. The duration of each wear test was 50 hours and tests were also performed on as-received material for comparison purposes. Data has been compared with results of tests performed on non-oxidised material for longer durations and also on tests without steam to examine the effect of different environments. Data collected from each test consists of mass change, stub height measurement and friction coefficient as well as visual inspection of the wear track. Within this paper, it is reported that both pre-ageing and the addition of steam during testing clearly influence the friction between material surfaces. (orig.)

  19. NEMD simulations for ductile metal sliding

    Energy Technology Data Exchange (ETDEWEB)

    Hammerberg, James E [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory; Ravelo, Ramon J [Los Alamos National Laboratory; Holian, Brad L [Los Alamos National Laboratory

    2011-01-31

    We have studied the sliding behavior for a 19 M Al(110)/Al(110) defective crystal at 15 GPa as a function of relative sliding velocity. The general features are qualitatively similar to smaller scale (1.4 M) atom simulations for Al(111)/Al(110) nondefective single crystal sliding. The critical velocity, v{sub c}, is approximately the same for the defective crystal as the size scaled v{sub c}. The lower velocity tangential force is depressed relative to the perfect crystal. The critical temperature, T*, is depressed relative to the perfect crystal. These conclusions are consistent with a lower value for f{sub c} for the defective crystal. The detailed features of structural transformation and the high velocity regime remain to be mapped.

  20. Complex technique for studying the machine part wear

    International Nuclear Information System (INIS)

    Grishko, V.A.; Zhushma, V.F.

    1981-01-01

    A technique to determine the wear of steel details rolling with sliding with circulatory lubrication is suggested. The functional diagram of the experimental device and structural diagrams of equipment to register the wear of tested samples and forming the lubricating layer between them, are considered. Results of testing three conples of disc samples and the data characterizing the dependence of sample wear on the value of contact stress are presented. The peculiarity of the device used is synchronous registering of the lubricating layer formation in the place of contact and detail mass loss in time which is realized correspondingly over discharge voltage on the lubricating layer and the intensity of radiation from detail wear products activated by neutrons. On the basis, of the investigation the conclusion is made that MEhF-1 oil has a greater antiwear effectiveness than the universal TAD-17 1 oil used presently [ru

  1. Dynamic SEM wear studies of tungsten carbide cermets

    Science.gov (United States)

    Brainard, W. A.; Buckley, D. H.

    1975-01-01

    Dynamic friction and wear experiments were conducted in a scanning electron microscope. The wear behavior of pure tungsten carbide and composite with 6 and 15 weight percent cobalt binder was examined. Etching of the binder was done to selectively determine the role of the binder in the wear process. Dynamic experiments were conducted as the WC and bonded WC cermet surfaces were transversed by a 50 micron radiused diamond stylus. These studies show that the predominant wear process in WC is fracture initiated by plastic deformation. The wear of the etched cermets is similar to pure WC. The presence of the cobalt binder reduces both friction and wear. The cementing action of the cobalt reduces granular separation and promotes a dense polished layer because of its low shear strength film-forming properties. The wear debris generated from unetched surface is approximately the same composition as the bulk.

  2. Presentation = Speech + Slides

    Directory of Open Access Journals (Sweden)

    Derik Badman

    2008-12-01

    Full Text Available Back in October, Aaron Schmidt posted “HOWTO give a good presentation” to his blog walking paper. His second bullet point of “thoughts” on good presentations is: Please don’t fill your slides with words. Find some relevant and pretty pictures to support what you’re saying. You can use the pictures to remind yourself what you’re going [...

  3. Adhesion and wear properties of boro-tempered ductile iron

    International Nuclear Information System (INIS)

    Kayali, Yusuf; Yalcin, Yilmaz; Taktak, Suekrue

    2011-01-01

    Highlights: → In this study, the wear and adhesion properties of BDI were investigated. → Boro-tempering process under several heat treatment conditions was examined. → Optical microscope, SEM and XRD analysis were carried out to investigate the microstructure. → It was observed that boro-tempering process improves micro-hardness and wear properties of ductile irons. -- Abstract: In this study, adhesion and wear properties of boro-tempered ductile iron (BDI) were investigated. Boro-tempering was carried out on two stage processes i.e. boronizing and tempering. At the first stage, ductile iron samples were boronized by using pack process at 900 o C for 1, 3, and 5 h and then, secondly tempered at 250, 300, 350, and 400 o C for 1 h. X-ray diffraction (XRD) analysis of boro-tempered samples showed that FeB and Fe 2 B phases were found on the surface of the samples. The Daimler-Benz Rockwell-C adhesion test was used to assess the adhesion of boride layer. Test result showed that adhesion decreased with increasing boriding time and increased with increasing tempering temperature. Dry sliding wear tests of these samples were performed against Al 2 O 3 ball at a constant sliding speed and loads of 5 and 10 N. Wear tests indicated that boro-tempering heat treatment increased wear resistance of ductile iron. In addition, it was found that while wear rate of boro-tempered samples decreased with increasing boriding time, there is no significant affect of tempering temperature on wear rate.

  4. A WEAR MODEL FOR DIESEL ENGINE EXHAUST VALVES

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Peter Julian [ORNL

    2009-11-01

    run for hundreds of hours in heavy-duty diesels provided insights into the kinds of complexity that the contact conditions in engines can produce, and suggested the physical basis for the current approach to modeling. The model presented here involves four terms, two representing the valve response and two for its mating seat material. The model's structure assumes that wear that takes place under a complex combination of plastic deformation, tangential shear, and oxidation. Tribolayers form, are removed, and may reform. Layer formation affects the friction forces in the interface, and in turn, the energy available to do work on the materials to cause wear. To provide friction data for the model at various temperatures, sliding contact experiments were conducted from 22 to 850 C in a pin-on-disk apparatus at ORNL. In order to account for the behavior of different materials and engine designs, parameters in all four terms of the model can be adjusted to account for wear-in and incubation periods before the dominant wear processes evolve to their steady-state rates. For example, the deformation rate is assumed to be maximum during the early stages of operation, and then, due to material work-hardening and the increase in nominal contact area (which reduces the load per unit area), decreases to a lower rate at long times. Conversely, the rate of abrasion increases with time or number of cycles due to the build-up of oxides and tribo-layers between contact surfaces. The competition between deformation and abrasion results in complex, non-linear behavior of material loss per cycle of operation. Furthermore, these factors are affected by valve design features, such as the angle of incline of the valve seat. Several modeling scenarios are presented to demonstrate how the wear profile versus number of cycles changes in response to: (a) different relative abrasion rates of the seat and valve materials, (b) the friction coefficient as a function of temperature, (c) the

  5. Slide system for machine tools

    Science.gov (United States)

    Douglass, Spivey S.; Green, Walter L.

    1982-01-01

    The present invention relates to a machine tool which permits the machining of nonaxisymmetric surfaces on a workpiece while rotating the workpiece about a central axis of rotation. The machine tool comprises a conventional two-slide system (X-Y) with one of these slides being provided with a relatively short travel high-speed auxiliary slide which carries the material-removing tool. The auxiliary slide is synchronized with the spindle speed and the position of the other two slides and provides a high-speed reciprocating motion required for the displacement of the cutting tool for generating a nonaxisymmetric surface at a selected location on the workpiece.

  6. Characteristics of fracture during the approach process and wear mechanism of a silicon AFM tip

    International Nuclear Information System (INIS)

    Chung, Koo-Hyun; Lee, Yong-Ha; Kim, Dae-Eun

    2005-01-01

    The wear of an atomic force microscope (AFM) tip is one of the crucial issues in AFM as well as in other probe-based applications. In this work, wear tests under extremely low normal load using an AFM were conducted. Also, in order to understand the nature of silicon tip wear, the wear characteristics of crystal silicon and amorphous silicon oxide layer were investigated by a high-resolution transmission electron microscope (HRTEM). It was found that fracture of the tip readily occurred due to impact during the approach process. Experimental results showed that the impact should be below 0.1 nN s to avoid significant fracture of the tip. Also, it was observed that wear of the amorphous layer, formed at the end of the tip, occurred at the initial stage of the silicon tip damage process. Based on Archard's wear law, the wear coefficient of the amorphous layer was in the range of 0.009-0.014. As for the wear characteristics of the silicon tip, it was shown that wear occurred gradually under light normal load and the wear rate decreased with increase in the sliding distance. As for the wear mechanism of the silicon tip, oxidation wear was identified to be the most significant. It was shown that the degree of oxidation was higher under high normal load and in a nitrogen environment, oxidation of the silicon tip was reduced

  7. Wear resistance of layers hard faced by the high-alloyed filler metal

    Directory of Open Access Journals (Sweden)

    Dušan Arsić

    2016-10-01

    Full Text Available The objective of this work was to determine the wear resistance of layers hard faced by the high-alloyed filler metal, with or without the austenite inter-layer, on parts that operate at different sliding speeds in conditions without lubrication. The samples were hard faced with the filler metal E 10-UM-60-C with high content of C, Cr and W. Used filler metal belongs into group of alloys aimed for reparatory hard facing of parts damaged by abrasive and erosive wear and it is characterized by high hardness and wear resistance. In experiments, the sliding speed and the normal loading were varied and the wear scar was monitored, based on which the volume of the worn material was calculated analytically. The contact duration time was monitored over the sliding path of 300 mm. The most intensive wear was established for the loading force of 100 N and the sliding speed of 1 m.s-1, though the significant wear was also noticed in conditions of the small loading and speed of 0.25 m.s-1, which was even greater that at larger speeds.

  8. Investigation of counterface surface topography effects on the wear and transfer behaviour of a POM-20% PTFE composite

    NARCIS (Netherlands)

    Franklin, S.E.; de Kraker, A.

    2003-01-01

    In order to gain greater insight into the relation between the wear rate, counterface surface topography and the characteristics of the transfer layer formed, a series of wear experiments have been performed with a commercial POM-20% PTFE composite sliding against hardened tool steel counterfaces in

  9. Wear Behavior of Plasma Spray Deposited and Post Heat-Treated Hydroxyapatite (HA)-Based Composite Coating on Titanium Alloy (Ti-6Al-4V) Substrate

    Science.gov (United States)

    Kumari, Renu; Majumdar, Jyotsna Dutta

    2018-04-01

    The present study concerns a detailed evaluation of wear resistance property of plasma spray deposited composite hydroxyapatite (HA)-based (HA-50 wt pct TiO2 and HA-10 wt pct ZrO2) bioactive coatings developed on Ti-6Al-4V substrate and studying the effect of heat treatment on it. Heat treatment of plasma spray deposited samples has been carried out at 650 °C for 2 hours (for HA-50 wt pct TiO2 coating) and at 750 °C for 2 hours (for HA-10 wt pct ZrO2 coating). There is significant deterioration in wear resistance for HA-50 wt pctTiO2 coating and a marginal deterioration in wear resistance for HA-10 wt pct ZrO2 coating in as-sprayed state (as compared to as-received Ti-6Al-4V) which is, however, improved after heat treatment. The coefficient of friction is marginally increased for both HA-50 wt pct TiO2 and HA-10 wt pct ZrO2 coatings in as-sprayed condition as compared to Ti-6Al-4V substrate. However, coefficient of friction is decreased for both HA-50 wt pct TiO2 and HA-10 wt pct ZrO2 coatings after heat-treated condition as compared to Ti-6Al-4V substrate. The maximum improvement in wear resistance property is, however, observed for HA-10 wt pct ZrO2 sample after heat treatment. The mechanism of wear has been investigated.

  10. Microstructure and Wear Behavior of FeCoCrNiMo0.2 High Entropy Coatings Prepared by Air Plasma Spray and the High Velocity Oxy-Fuel Spray Processes

    Directory of Open Access Journals (Sweden)

    Tianchen Li

    2017-09-01

    Full Text Available In the present research, the spherical FeCoCrNiMo0.2 high entropy alloy (HEA powders with a single FCC solid solution structure were prepared by gas atomization. Subsequently, the FeCoCrNiMo0.2 coatings with a different content of oxide inclusions were prepared by air plasma spraying (APS and high-velocity oxy-fuel spraying (HVOF, respectively. The microstructure, phase composition, mechanical properties, and tribological behaviors of these HEA coatings were investigated. The results showed that both HEA coatings showed a typical lamellar structure with low porosity. Besides the primary FCC phase, a mixture of Fe2O3, Fe3O4, and AB2O4 (A = Fe, Co, Ni, and B = Fe, Cr was identified as the oxide inclusions. The oxide content of the APS coating and HVOF coating was calculated to be 47.0% and 12.7%, respectively. The wear resistance of the APS coating was approximately one order of magnitude higher than that of the HVOF coating. It was mainly attributed to the self-lubricated effect caused by the oxide films. The mass loss of the APS coating was mainly ascribed to the breakaway of the oxide film, while the main wear mechanism of the HVOF coating was the abrasive wear.

  11. Simulations of atomic-scale sliding friction

    DEFF Research Database (Denmark)

    Sørensen, Mads Reinholdt; Jacobsen, Karsten Wedel; Stoltze, Per

    1996-01-01

    Simulation studies of atomic-scale sliding friction have been performed for a number of tip-surface and surface-surface contacts consisting of copper atoms. Both geometrically very simple tip-surface structures and more realistic interface necks formed by simulated annealing have been studied....... Kinetic friction is observed to be caused by atomic-scale Stick and slip which occurs by nucleation and subsequent motion of dislocations preferably between close-packed {111} planes. Stick and slip seems ro occur in different situations. For single crystalline contacts without grain boundaries...... pinning of atoms near the boundary of the interface and is therefore more easily observed for smaller contacts. Depending on crystal orientation and load, frictional wear can also be seen in the simulations. In particular, for the annealed interface-necks which model contacts created by scanning tunneling...

  12. Experimental fretting-wear studies of steam generator materials

    International Nuclear Information System (INIS)

    Fisher, N.J.; Chow, A.B.; Weckwerth, M.K.

    1994-01-01

    Flow-induced vibration of steam generator tubes results in fretting-wear damage due to impacting and rubbing of the tubes against their supports. This damage can be predicted by computing tube response to flow-induced excitation forces using analytical techniques, and then relating this response to resultant wear damage using experimentally-derived wear coefficients. Fretting-wear of steam generator materials has been studied experimentally at Chalk River Laboratories for two decades. Tests are conducted in machines that simulate steam generator environmental conditions and tube-to-support dynamic interactions. Different tube and support materials, tube-to-support clearances and tube support geometries have been studied. As well, the effect of environmental conditions, such as temperature, oxygen content, pH and chemistry control additive, have been investigated. Early studies showed that damage was related to contact force as long as other parameters, such as geometry and motion were held constant. Later studies have shown that damage is related to a parameter called work-rate, which combines both contact force and sliding distance. Results of short- and long-term fretting-wear tests for CANDU steam generator materials at realistic environmental conditions are presented. These results demonstrate that work-rate is appropriate correlating parameter for impact-sliding interaction

  13. Wear reduction through piezoelectrically-assisted ultrasonic lubrication

    International Nuclear Information System (INIS)

    Dong, Sheng; J Dapino, Marcelo

    2014-01-01

    Traditional lubricants are undesirable in harsh aerospace environments and certain automotive applications. Ultrasonic vibrations can be used to reduce and modulate the effective friction coefficient between two sliding surfaces. This paper investigates the relationship between friction force reduction and wear reduction in ultrasonically lubricated surfaces. A pin-on-disc tribometer is modified through the addition of a piezoelectric transducer which vibrates the pin at 22 kHz in the direction perpendicular to the rotating disc surface. Friction and wear metrics including volume loss, surface roughness, friction forces and apparent stick-slip effects are measured without and with ultrasonic vibrations at three different sliding velocities. SEM imaging and 3D profilometry are used to characterize the wear surfaces and guide model development. Over the range of speeds considered, ultrasonic vibrations reduce the effective friction force up to 62% along with a wear reduction of up to 49%. A simple cube model previously developed to quantify friction force reduction is implemented which describes wear reduction within 15% of the experimental data. (paper)

  14. Impact fretting wear in CO2-based environments

    International Nuclear Information System (INIS)

    Levy, G.; Morri, J.

    1985-01-01

    An impact wear model, based on the load-sliding distance proportionality of wear and the mechanical response of the impacting bodies, was derived and tested against experiment. The experimental work was carried out on a twin vibrator rig capable of repetitive impact of a moving specimen against a stationary target material. The impact wear characteristics of three materials (mild steel, 9Cr-1Mo steel and austenitic 316 steel) against 310 stainless steel were examined over a range of temperatures (18-600 0 C). Additionally the effects of variations in the mechanical parameters (incident energy, ξ i , number N of impacts and angle of incidence φ) as a function of temperature were evaluated for mild steel only. The model was verified for impacting within a stable wear regime at 100 0 C for 9Cr-1Mo steel. The emergence of a severe-to-mild wear transition at elevated temperatures (200-400 0 C), however, introduced an energy and a 'numbers of cycles' effect that caused apparent deviations from theory. It was concluded that for stable single-mechanism wear regimes (metallic, oxidative etc.) oblique elastic impacts with a gross slip component were accurately described by the proposed impact wear model. (orig.)

  15. A comparative wear study on Al-Li and Al-Li/SiC composite

    Energy Technology Data Exchange (ETDEWEB)

    Okumus, S. Cem, E-mail: cokumus@sakarya.edu.tr; Karslioglu, Ramazan, E-mail: cokumus@sakarya.edu.tr; Akbulut, Hatem, E-mail: cokumus@sakarya.edu.tr [Sakarya University Engineering Faculty, Department of Metallurgical and Materials Engineering, Esentepe Campus, 54187, Sakarya (Turkey)

    2013-12-16

    Aluminum-lithium based unreinforced (Al-8090) alloy and Al-8090/SiCp/17 vol.% metal matrix composite produced by extrusion after spray co-deposition. A dry ball-on disk wear test was carried out for both alloy and composite. The tests were performed against an Al{sub 2}O{sub 3} ball, 10 mm in diameter, at room temperature and in laboratory air conditions with a relative humidity of 40-60%. Sliding speed was chosen as 1.0 ms{sup −1} and normal loads of 1.0, 3.0 and 5.0 N were employed at a constant sliding distance of 1000 m. The wear damage on the specimens was evaluated via measurement of wear depth and diameter. Microstructural and wear characterization was carried out via scanning electron microscopy (SEM). The results showed that wear loss of the Al-8090/SiC composite was less than that of the Al-8090 matrix alloy. Plastic deformation observed on the wear surface of the composite and the matrix alloy, and the higher the applied load the greater the plastic deformation. Scanning electron microscopy examinations of wear tracks also reveal that delamination fracture was the dominant wear mechanism during the wear progression. Friction coefficient was maximum at the low applied load in the case of the Al-8090/SiC composite while a gradual increase was observed with applied load for the matrix alloy.

  16. Abrasive Wear Resistance of the Iron- and WC-based Hardfaced Coatings Evaluated with Scratch Test Method

    Directory of Open Access Journals (Sweden)

    A. Vencl

    2013-06-01

    Full Text Available Abrasive wear is one of the most common types of wear, which makesabrasive wear resistance very important in many industries. Thehard facing is considered as useful and economical way to improve theperformance of components submitted to severe abrasive wear conditions, with wide range of applicable filler materials. The abrasive wear resistance of the three different hardfaced coatings (two iron‐based and one WC‐based, which were intended to be used for reparation of the impact plates of the ventilation mill, was investigated and compared. Abrasive wear tests were carried‐out by using the scratch tester under the dry conditions. Three normal loads of 10, 50 and 100 N and the constant sliding speed of 4 mm/s were used. Scratch test was chosen as a relatively easy and quick test method. Wear mechanism analysis showed significant influence of the hardfaced coatings structure, which, along with hardness, has determined coatings abrasive wear resistance.

  17. Experimental Investigation on Friction and Wear Properties of Different Steel Materials

    Directory of Open Access Journals (Sweden)

    M.A. Chowdhury

    2013-03-01

    Full Text Available Friction coefficient and wear rate of different steel materials are investigated and compared in this study. In order to do so, a pin on disc apparatus is designed and fabricated. Experiments are carried out when different types of disc materials such as stainless steel 314 (SS 314, stainless steel 202 (SS 202 and mild steel slide against stainless steel 314 (SS 314 pin. Experiments are conducted at normal load 10, 15 and 20 N, sliding velocity 1, 1.5 and 2 m/s and relative humidity 70%. At different normal loads and sliding velocities, variations of friction coefficient with the duration of rubbing are investigated. The obtained results show that friction coefficient varies with duration of rubbing, normal load and sliding velocity. In general, friction coefficient increases for a certain duration of rubbing and after that it remains constant for the rest of the experimental time. The obtained results reveal that friction coefficient decreases with the increase in normal load for all the tested materials. It is also found that friction coefficient increases with the increase in sliding velocity for all the materials investigated. Moreover, wear rate increases with the increase in normal load and sliding velocity for SS 314, SS 202 and mild steel. In addition, at identical operating condition, the magnitudes of friction coefficient and wear rate are different for different materials depending on sliding velocity and normal load.

  18. Tribological behavior of Al-WC nano-composites fabricated by ultrasonic cavitation assisted stir-cast method

    Science.gov (United States)

    Pal, Arpan; Poria, Suswagata; Sutradhar, Goutam; Sahoo, Prasanta

    2018-03-01

    In the present study, the effects of WC nano-particles content on the microstructure, hardness, wear, and friction behavior of aluminum matrix composites are investigated. Al-WC nano composites with varying wt% of WC (0, 1, 1.5, and 2) are fabricated using ultrasonic cavitation assisted stir-cast method. The microstructure of the nano-composite samples is analyzed using optical microscopy and scanning electron microscopy. Elemental composition is determined by energy dispersive x-ray analysis. Vicker’s microhardness test is performed in different locations on the composite sample surface with a load of 50 gf and 10s dwell time. Wear and friction of the composites under dry sliding is studied using a pin-on-disk tribotester for varying normal load (10–40 N) and sliding speed (0.1–0.4 m/s). Uniform distribution of nano-WC is observed over composite surface without noticeable clustering. Reinforcement of nano-WC particles improves wear resistance and frictional behavior of the composite. Hardness is seen to increase with increase in wt% of nano-particles. Wear behavior of composites depends on formation of layers over the surface mixed with oxidized debris and counter-face particles. Wear mechanism changes from adhesion to abrasion with increase in wt% of hard nano particles.

  19. Tribological study on rapeseed oil with nano-additives in close contact sliding situation

    Science.gov (United States)

    Gupta, Rajeev Nayan; Harsha, A. P.; Singh, Sagar

    2018-02-01

    The present work deals with the tribological evaluation of three types of nano-additives, i.e., copper oxide (CuO; ≈ 151.2 nm), cerium oxide (CeO2; ≈ 80 nm) and polytetrafluoroethylene (PTFE; ≈ 90.4 nm) with rapeseed oil under steel-steel sliding contacts. The nano-additives concentrations in the base oil were 0.1, 0.25 and 0.5% w/v for the lubricant formulation. Further, the rapeseed oil was also epoxidized by a chemical method and the tribological behavior was compared with the base oil (unmodified oil) at similar nano-additives concentrations. The ASTM standards were followed for the study of wear preventive and extreme-pressure analysis of nanolubricants, and it was carried out using four-ball tester. In the antiwear test, CeO2 and PTFE nano-additives have shown the significant reduction in the wear scar diameter at the concentration of 0.1% w/v. In the extreme-pressure test, 0.5% w/v concentration was optimum for oxide nanoparticles; however, PTFE nanoparticles did not show positive effect with both the base oils. Different characterization techniques were employed to confirm the oil modification and for the study of the worn surfaces.

  20. Microstructure and wear resistance of in situ porous TiO/Cu composites

    Science.gov (United States)

    Qin, Qingdong; Huang, Bowei; Li, Wei

    2016-07-01

    An in situ porous TiO/Cu composite is successfully prepared using powder metallurgy by the reaction of Ti2CO and Cu powder. Morphological examination of the composite shows that the porosity of composites lies in the range between 10.2% and 35.2%. Dry sliding un-lubricated wear tests show that the wear resistance of the composite is higher than that of the Cu-Al alloy ingot. The coefficient of friction test shows that, as the volume fraction of the reinforced phase increases, the coefficient of friction decreases. The wear rate variation trend of the oil-lubricated wear test results is similar to that of the un-lubricated wear test results. The coefficient of friction for oil lubrication is similar for different volume fractions of the reinforced phase. The wear resistance of the composite at a sliding velocity of 200 rpm is slightly larger than that at 50 rpm. The porosity of the composites enhances the high-velocity oil-lubricated sliding wear resistance.

  1. Nitrogen implantation of steels: A treatment which can initiate sustained oxidative wear

    International Nuclear Information System (INIS)

    Hale, E.B.; Reinbold, R.; Missouri Univ., Rolla; Kohser, R.A.

    1987-01-01

    Falex wear tests on mild (SAE 3135) steel samples treated by either nitrogen implantation (2.5x10 17 N 2 + cm -2 at 180 keV) or low temperature (about 315 0 C) oxidation are reported. The results show that both treatments lead to about an order-of-magnitude reduction in the long-term wear rate of the steel. In addition to the wear rate measurements, the wear member asymmetry behavior, scanning electron microscopy studies, Auger spectra and sputter profiles all indicate that the wear modes induced by both treatments are the same and are oxidative wear. These results confirm the previously proposed initiator-sustainer wear model in which implanted nitrogen simply acts as an initiator of favorable oxidative wear but is not directly involved in maintaining the sustained wear resistance. Possible mechanisms for both the initiation process and the sustained wear process are reviewed and discussed. (orig.)

  2. SLIDES: a program to draw slides and posters

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, R.; Schofield, J.

    1977-04-01

    SLIDES is a program which takes text and commands as input and prepares lettered slides and posters. When run on the time-sharing computer, the program can display its output on an interactive graphics terminal; in batch, it can direct its graphical output to a variety of plotters. The program uses DISSPLA graphical subroutines and standard ANL plotter subroutines. This report contains material written for the beginning user, who should be able to produce useful slides or posters by following the examples. This report also serves as a complete reference for the SLIDES program. 4 figures.

  3. Investigation of structure, adhesion strength, wear performance and corrosion behavior of platinum/ruthenium/nitrogen doped diamond-like carbon thin films with respect to film thickness

    International Nuclear Information System (INIS)

    Khun, N.W.; Liu, E.

    2011-01-01

    Research highlights: → Sputtered PtRuN-DLC thin films were fabricated with different film thicknesses. → The graphitization of the films increased with increased film thickness. → The wear resistance of the films increased though their adhesion strength decreased. → The corrosion potentials of the films shifted to more negative values. → However, the corrosion currents of the films decreased. - Abstract: In this study, the corrosion performance of platinum/ruthenium/nitrogen doped diamond-like carbon (PtRuN-DLC) thin films deposited on p-Si substrates using a DC magnetron sputtering deposition system in a 0.1 M NaCl solution was investigated using potentiodynamic polarization test in terms of film thickness. The effect of the film thickness on the chemical composition, bonding structure, surface morphology, adhesion strength and wear resistance of the PtRuN-DLC films was studied using X-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy, atomic force microscopy (AFM), micro-scratch test and ball-on-disc tribotest, respectively. It was found that the wear resistance of the PtRuN-DLC films apparently increased with increased film thickness though the adhesion strength of the films decreased. The corrosion results revealed that the increased concentration of sp 2 bonds in the PtRuN-DLC films with increased film thickness shifted the corrosion potentials of the films to more negative values but the decreased porosity density in the films significantly decreased the corrosion currents of the films.

  4. Tribological Behavior of γ-TiAl Matrix Composites with Different Contents of Multilayer Graphene

    Science.gov (United States)

    Yan, Zhao; Shen, Qiao; Shi, Xiaoliang; Yang, Kang; Zou, Jialiang; Huang, Yuchun; Zhang, Ao; Ibrahim, Ahmed Mohamed Mahmoud; Wang, Zhihai

    2017-04-01

    In this study, the effect of friction layer thickness and subsurface nano-hardness of wear track on tribological behavior of γ-TiAl matrix composites is investigated. The results of dry sliding tribolocial tests of γ-TiAl matrix composites with 0-2.25 wt.% multilayer graphene (MLG) (0.25 wt.% in tolerance) under different applied loads are reported. The testing results show that the optimized addition amount of MLG is 1.75 wt.% at 12 N (friction layer thickness 3.23 µm, subsurface nano-hardness of wear track 9.03 GPa). It can be found that a continuous and thick friction layer is formed in γ-TiAl-1.75 wt.% MLG at 12 N, resulting in a lower friction coefficient of 0.31 and wear rate of 2.09 × 10-5 mm3 N-1 m-1. During dry sliding process, the high subsurface nano-hardness of wear track leads to the increase in resisting plastic deformation capacity and reduces the material loss. Meanwhile, the thick friction layer contains MLG with high tensile strength which is easily sheared off. Hence, γ-TiAl matrix composites show excellent tribological performance of a friction-reducing and an increase in wear resistance. The investigation shows that γ-TiAl-1.75 wt.% MLG, due to its excellent tribological behavior at 12 N, can be chosen as a promising structural material for minimizing friction- and wear-related mechanical failures in sliding mechanical components.

  5. Couple of biomimetic surfaces with different morphologies for remanufacturing nonuniform wear rail surface

    Science.gov (United States)

    Sui, Qi; Zhou, Hong; Yang, Lin; Zhang, Haifeng; Feng, Li; Zhang, Peng

    2018-02-01

    In this work, biomimetic laser treatment was performed on repairing and remanufacturing the nonuniform worn rail surface. The wearing depth distribution of three work regions of a failure rail surface was discussed, and different thickness hardening layers with different microstructure, microhardness and wear resistances were detected from the worm surfaces. Varying wear resistances of the surfaces with different biomimetic morphologies were obtained by biomimetic laser treatments, and the corresponding effect on the lubrication sliding wear of treated and untreated surfaces were studied for comparative study. In addition, the relationship between wear resistance and the spacing of units was also provided, which can lay the important theoretical foundation for avoiding the wear resistance of the serious worn surface is less than that of the slight worn surface in the future practical applications.

  6. An experimental modeling and acoustic emission monitoring of abrasive wear in a steel/diabase pair

    Science.gov (United States)

    Korchuganov, M. A.; Filippov, A. V.; Tarasov, S. Yu.; Podgornyh, O. A.; Shamarin, N. N.; Filippova, E. O.

    2016-11-01

    The earthmoving of permafrost soil is a critical task for excavation of minerals and construction on new territories. Failure by abrasive wear is the main reason for excavation parts of earthmoving and soil cutting machines. Therefore investigation of this type of wear is a challenge for developing efficient and wear resistant working parts. This paper is focused on conducting tribological experiments with sliding the steel samples over the surface of diabase stone sample where abrasive wear conditions of soil cutting are modeled experimentally. The worn surfaces of all samples have been examined and transfer of metal and stone particles revealed. The acoustic emission (AE) signals have been recorded and related to the results of worn surface analysis. he acoustic emission (AE) signals have been recorded and related to the results of worn surface analysis. As shown the wear intensity correlates to that of acoustic emission. Both acoustic emission signal median frequency and energy are found to be sensitive to the wear mode.

  7. Study on the friction and wear properties of carbon fabric composites reinforced with micro- and nano-particles

    International Nuclear Information System (INIS)

    Zhang Zhaozhu; Su Fenghua; Wang Kun; Jiang Wei; Men Xuehu; Liu Weimin

    2005-01-01

    The carbon fabric composites filled with the particulates of polyfluo-150 wax (PFW), nano-particles of ZnO (nano-ZnO), and nano-particles of SiC (nano-SiC), respectively, were prepared by dip-coating of the carbon fabric in a phenolic resin containing the particulates to be incorporated and the successive curing. The friction and wear behaviors of the carbon fabric composites sliding against AISI-1045 steel in a pin-on-disk configuration are evaluated on a Xuanwu-III high-temperature friction and wear tester. The morphologies of the worn surfaces of the filled carbon fabric composites and the counterpart steel pins are analyzed by means of scanning electron microscopy. The effect of the fillers on the adhesion strength of the adhesive is evaluated using a DY35 universal materials tester. It is found that the fillers PFW, nano-ZnO, and nano-SiC contribute to significantly increasing anti-wear abilities of the carbon fabric composites, however, nano-SiC increase the friction coefficient of the carbon fabric composites. The wear rates of the composites at elevated temperature above 180 deg. C are much larger than that below 180 deg. C, which attribute to the degradation and decomposition of the adhesive resin at an excessively elevated temperature. That the interface bonding strength among the carbon fabric, the adhesive, and the particles is significantly increased after solidification and with the transferred film of the varied features largely account for the increased wear-resistance of the filled carbon fabric composites as compared with the unfilled one

  8. Wear Characteristics of Hybrid Composites Based on Za27 Alloy Reinforced With Silicon Carbide and Graphite Particles

    Directory of Open Access Journals (Sweden)

    S. Mitrović

    2014-06-01

    Full Text Available The paper presents the wear characteristics of a hybrid composite based on zinc-aluminium ZA27 alloy, reinforced with silicon-carbide and graphite particles. The tested sample contains 5 vol.% of SiC and 3 vol.% Gr particles. Compocasting technique has been used to prepare the samples. The experiments were performed on a “block-on-disc” tribometer under conditions of dry sliding. The wear volumes of the alloy and the composite were determined by varying the normal loads and sliding speeds. The paper contains the procedure for preparation of sample composites and microstructure of the composite material and the base ZA27 alloy. The wear surface of the composite material was examined using the scanning electronic microscope (SEM and energy dispersive spectrometry (EDS. Conclusions were obtained based on the observed impact of the sliding speed, normal load and sliding distance on tribological behaviour of the observed composite.

  9. Features wear nodes mechanization wing aircraft operating under dynamic loads

    Directory of Open Access Journals (Sweden)

    А.М. Хімко

    2009-03-01

    Full Text Available  The conducted researches of titanic alloy ВТ-22 at dynamic loading with cycled sliding and dynamic loading in conditions of rolling with slipping. It is established that roller jamming in the carriage increases wear of rod of mechanization of a wing to twenty times. The optimum covering for strengthening wearied sites and restoration of working surfaces of wing’s mechanization rod is defined.

  10. Adhesive Wear Performance of CFRP Multilayered Polyester Composites Under Dry/wet Contact Conditions

    Science.gov (United States)

    Danaelan, D.; Yousif, B. F.

    The tribo-performance of a new engineering composite material based on coconut fibers was investigated. In this work, coconut fibers reinforced polyester (CFRP) composites were developed. The tribo-experiments were conducted by using pin-on-disc machine under dry and wet sliding contact condition against smooth stainless steel counterface. Worn surfaces were observed using optical microscope. Friction coefficient and specific wear rate were presented as a function of sliding distance (0-0.6 km) at different sliding velocities (0.1-0.28 m/s). The effect of applied load and sliding velocity was evaluated. The results showed that all test parameters have significant influence on friction and wear characteristics of the composites. Moreover, friction coefficient increased as the normal load and speed increased, the values were about 0.7-0.9 under dry contact condition. Meanwhile, under wet contact condition, there was a great reduction in the friction coefficient, i.e. the values were about 0.1-0.2. Furthermore, the specific wear rates were found to be around 2-4 (10-3) mm3/Nm under dry contact condition and highly reduced under wet condition. In other words, the presence of water as cleaner and polisher assisted to enhance the adhesive wear performance of CFRP by about 10%. The images from optical microscope showed evidence of adhesive wear mode with transition to abrasive wear mode at higher sliding velocities due to third body abrasion. On the other hand, optical images for wet condition showed less adhesive wear and smooth surfaces.

  11. Influence of halogen irradiance on short- and long-term wear resistance of resin-based composite materials.

    LENUS (Irish Health Repository)

    Bhamra, Gurcharn S

    2009-02-01

    The Oregon Health Science University (OHSU) four-chamber oral wear simulator was used to examine the impact of halogen irradiance on the short- and long-term wear behavior of four-methacrylate resin-based composites (RBCs). The hypothesis proposed was that exacerbated wear would occur following the long-term wear of RBCs irradiated under non-optimized irradiance conditions.

  12. Friction and wear properties of Cu and Fe-based P/M bearing materials

    International Nuclear Information System (INIS)

    Tufekci, Kenan; Kurbanoglu, Cahit; Durak, Ertugrul; Tunay, R. Fatih

    2006-01-01

    The performances of porous bearings under different operating conditions were experimentally investigated in this study. Material groups studied are 90%Cu + 10%Sn bronze and 1%C + % balance Fe iron-based self-lubricating P/M bearings at constant (85%) density. In the experiments, the variation of the coefficient of friction and wear ratio of those two different group materials for different sliding speeds, loads, and temperatures were investigated. As a result, the variation of the friction coefficient - temperature for both constant load, and constant sliding speed, friction coefficient - average bearing pressure, PV - wear loss and temperature-wear loss curves were plotted and compared with each other for two materials, separately. The test results showed that Cu-based bearings have better friction and wear properties than Fe-based bearings

  13. Analysis of Heat Partitioning During Sliding Contact at High Speed and Pressure

    Science.gov (United States)

    2014-03-27

    the numerical results developed are compared in Chapter 7. Malinowski , Lenard and Davies (35) used the mechanical models of the hot/warm forging...R.F.Harder. “Transient heat partition factor for a sliding railcar wheel,” Wear, 261: 932-936 (2006). 35. Malinowski , Z., J.G.Lenard, and M.E.Davies

  14. Control of erosive tooth wear: possibilities and rationale

    Directory of Open Access Journals (Sweden)

    Mônica Campos Serra

    2009-06-01

    Full Text Available Dental erosion is a type of wear caused by non bacterial acids or chelation. There is evidence of a significant increase in the prevalence of dental wear in the deciduous and permanent teeth as a consequence of the frequent intake of acidic foods and drinks, or due to gastric acid which may reach the oral cavity following reflux or vomiting episodes. The presence of acids is a prerequisite for dental erosion, but the erosive wear is complex and depends on the interaction of biological, chemical and behavioral factors. Even though erosion may be defined or described as an isolated process, in clinical situations other wear phenomena are expected to occur concomitantly, such as abrasive wear (which occurs, e.g, due to tooth brushing or mastication. In order to control dental loss due to erosive wear it is crucial to take into account its multifactorial nature, which predisposes some individuals to the condition.

  15. Microstructure and wear resistance of laser cladded composite coatings prepared from pre-alloyed WC-NiCrMo powder with different laser spots

    Science.gov (United States)

    Yao, Jianhua; Zhang, Jie; Wu, Guolong; Wang, Liang; Zhang, Qunli; Liu, Rong

    2018-05-01

    The distribution of WC particles in laser cladded composite coatings can significantly affect the wear resistance of the coatings under aggressive environments. In this study, pre-alloyed WC-NiCrMo powder is deposited on SS316L via laser cladding with circular spot and wide-band spot, respectively. The microstructure and WC distribution of the coatings are investigated with optical microscope (OM), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and X-ray diffraction (XRD). The wear behavior of the coatings is investigated under dry sliding-wear test. The experimental results show that the partially dissolved WC particles are uniformly distributed in both coatings produced with circular spot and wide-band spot, respectively, and the microstructures consist of WC and M23C6 carbides and γ-(Ni, Fe) solid solution matrix. However, due to Fe dilution, the two coatings have different microstructural characteristics, resulting in different hardness and wear resistance. The wide-band spot laser prepared coating shows better performance than the circular spot laser prepared coating.

  16. Embeddability behaviour of tin-based bearing material in dry sliding

    International Nuclear Information System (INIS)

    Zeren, Adalet

    2007-01-01

    In this study, tin-based bearing material has been investigated in dry sliding conditions. The low Sb content (7%) is known as SAE 12 and is Sn-Sb-Cu alloy and is widely used in the automotive industry. Wear and friction characteristics were determined with respect to sliding distance, sliding speed and bearing load, using a Tecquipment HFN type 5 journal bearing test equipment. Scanning electron microscopy (SEM) and energy-disperse X-ray spectrography (EDX) are used to understand the tribological events, especially embeddability. Thus, the purpose of this study is to investigate the tribological properties of tin-based bearing alloy used especially in heavy industrial service conditions. Tests were carried out in dry sliding conditions, since despite the presence of lubricant film, under heavy service conditions dry sliding may occur from time to time, causing local wear. As a result of local wear, bearing materials and bearing may be out of their tolerance limits in their early lifetime. Embeddability is an important property due to inversely affecting the hardness and the strength of the bearing

  17. No sliding in time

    International Nuclear Information System (INIS)

    Shtengel, Kirill; Nayak, Chetan; Bishara, Waheb; Chamon, Claudio

    2005-01-01

    In this letter, we analyse the following apparent paradox: as has been recently proved by Hastings (2004 Phys. Rev. 69 104431), under a general set of conditions, if a local Hamiltonian has a spectral gap above its (unique) ground state (GS), all connected equal-time correlation functions of local operators decay exponentially with distance. On the other hand, statistical mechanics provides us with examples of 3D models displaying so-called sliding phases (O'Hern et al 1999 Phys. Rev. Lett. 83 2745) which are characterized by the algebraic decay of correlations within 2D layers and exponential decay in the third direction. Interpreting this third direction as time would imply a gap in the corresponding (2+1)D quantum Hamiltonian whi