About the mechanism for reducing the adhesion wear of the copper friction pair in the inert atmosphere by the nitrogen ions implantation method

The mechanisms of increasing the resistance of copper samples treated with a high-energy beam of nitrogen ions to adhesive wear during friction together with a copper counterbody in an argon atmosphere are studied. It was shown that the increase in wear resistance is complex and is associated with the action of mechanisms such as solid-solution hardening, grinding of copper grains, precipitation of the finely dispersed CuN3 phase, increase in the density of dislocations and internal stresses of the second kind in the surface layer . The maximum increase in wear resistance and microhardness (~ 4 and ~ 2.6 times, respectively, compared with the original copper) is observed about ion fluence of ~ 9×1017 ion/cm2. A further increase in fluencies leads to a decrease in wear resistance and microhardness due to the enlargement of the pores formed in the surface layer of copper as a result of implantation of nitrogen ions.

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Numerical Investigation of Thermal Stresses in Surface Layer of Si3N4 Ceramics in Laser Processing

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.806.104 ◽

2015 ◽

Vol 806 ◽

pp. 104-108

Author(s):

Valery V. Kuzin ◽

Sergey Fedorov ◽

Predrag Dašić ◽

Mike Portnoy

Keyword(s):

Finite Element Method ◽

Surface Layer ◽

Laser Processing ◽

Small Area ◽

Strain State ◽

Thermal Stresses ◽

Ceramic Materials ◽

High Energy ◽

Stress Fields ◽

Energy Beam

The laser processing has the ability for effective machining of ceramic materials because of high energy beam acting on a very small area. The stress-strain state of surface layer of Si3N4 ceramics in laser processing was investigated with the use of finite element method to compute the temperature and stress fields. The effect of heat flow on thermal stresses was discussed in terms of the results of the numerical experiment.

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THE ANALYSIS OF THE INFLUENCE OF LASER HEAT TREATMENT OF THE CRANKSHAFT JOURNAL ON WEAR RESISTANCE OF THE BEARING

Tribologia ◽

10.5604/01.3001.0010.7569 ◽

2016 ◽

Vol 266 (2) ◽

pp. 87-100 ◽

Cited By ~ 2

Author(s):

Marta PACZKOWSKA

Keyword(s):

Wear Resistance ◽

Surface Layer ◽

Laser Treatment ◽

Friction Pair ◽

Rapid Change ◽

Wear Test ◽

Test Results ◽

Test Load ◽

Wear Process ◽

Stabilization Period

The aim of the presented research was to evaluate wear effects of bearing elements in case of modification based on laser alloying with boron of journal surface layer. The research was performed on ZPG-IV tribology tester with journal-bearing friction pair. During the test load was applied progressively. SEM microscopes and non-contact 3D optical profilografometr was used to assess the test results. Study of the character of the wear process allowed to state, that after each increase of load during the test, rapid change of the value of oil temperature and the value of resistance in journal-pan contact was appeared. Then, the stabilization period was followed by. Some differences in the way of those processes between tested variants were noticed. Firstly, during the stabilization period larger thickness of the oil film at the journal-pan interface was notice in case of journal after laser treatment than in case of untreated journal. Secondly, it could be expected that oil temperature will be lower in case of longer time of tribological test for treated journal (than for untreated journal). It should favor better wear resistance of this kinematic node. Macro and microscopic observations of both types of surface after wear test allow to state, that journals after laser treatment were characterized by less wear effects, as cavities in the surface layer in comparison to untreated journals. More intensive wear of journals without treatment was confirmed by stereometric research and measurements of surface roughness parameters. This research allow to state positive laser treatment influence on the wear resistance of the journal. Although, there was no larger loss of the surface layer in case of pans after cooperation with hard journal after laser treatment (describe by the decrease of pans’ thickness) then loss of the surface layer in case of pans after cooperation with softer untreated journal (nearly 5-times softer than the surface layer of treated journal), the microscopic observations and measurement of the parameters of stereometric structure of their surface showed more intensive wear of pan after cooperation with treated journal.

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Effect of Pulsed High Energy Electron Beam on Surface Modification of AZ91 Magnesium Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.546-549.547 ◽

2007 ◽

Vol 546-549 ◽

pp. 547-550

Author(s):

Wei Lv ◽

Hui Zhao ◽

Zhong Han ◽

Zhen Liu

Keyword(s):

Wear Resistance ◽

Surface Layer ◽

Surface Modification ◽

Electron Beam ◽

Magnesium Alloy ◽

High Energy ◽

Az91 Alloy ◽

High Energy Electron ◽

Az91 Magnesium Alloy ◽

Az91 Magnesium

Effect of pulsed high-energy electron beam on the surface modification and the state of surface layer and wear resistance of AZ91 magnesium alloy have been investigated in this study. Optical microscope (OM) and X-ray diffraction (XRD) were employed to characterize the microstructure and phase composition of the modified surface layer. It was found that the thickness of melted layer on the surface varied with electron beam current and the numbers of pulses, the treated surface layer exhibited higher hardness than AZ91 alloy. The friction coefficient and the wear volume of AZ91 alloy after electron beam treatment decrease markedly. The wear resistance of treated samples were significantly improved, which may be attributed to high hardness as a result of grain refinement.

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Characterization of thermal barrier coatings formed by electon-beam physical vapor deposition (EB-PVD)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010015410x ◽

1989 ◽

Vol 47 ◽

pp. 426-427

Author(s):

Ozer Unal

Keyword(s):

Thermal Barrier Coatings ◽

Physical Vapor Deposition ◽

Ceramic Coating ◽

High Vacuum ◽

Ceramic Coatings ◽

High Energy ◽

Thermal Barrier ◽

Protective Oxide ◽

Barrier Coatings ◽

Energy Beam

Interest in ceramics as thermal barrier coatings for hot components of turbine engines has increased rapidly over the last decade. The primary reason for this is the significant reduction in heat load and increased chemical inertness against corrosive species with the ceramic coating materials. Among other candidates, partially-stabilized zirconia is the focus of attention mainly because ot its low thermal conductivity and high thermal expansion coefficient.The coatings were made by Garrett Turbine Engine Company. Ni-base super-alloy was used as the substrate and later a bond-coating with high Al activity was formed over it. The ceramic coatings, with a thickness of about 50 μm, were formed by EB-PVD in a high-vacuum chamber by heating the target material (ZrO2-20 w/0 Y2O3) above its evaporation temperaturef >3500 °C) with a high-energy beam and condensing the resulting vapor onto a rotating heated substrate. A heat treatment in an oxidizing environment was performed later on to form a protective oxide layer to improve the adhesion between the ceramic coating and substrate. Bulk samples were studied by utilizing a Scintag diffractometer and a JEOL JXA-840 SEM; examinations of cross-sectional thin-films of the interface region were performed in a Philips CM 30 TEM operating at 300 kV and for chemical analysis a KEVEX X-ray spectrometer (EDS) was used.

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The promises and perfidy of cryomicroscopy and analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010016964x ◽

1994 ◽

Vol 52 ◽

pp. 382-383

Author(s):

Patrick Echlin

Keyword(s):

Low Temperature ◽

High Energy ◽

Short Paper ◽

List Type ◽

Time Resolved ◽

Energy Beam ◽

Cellular Analysis ◽

Dissolved Ions ◽

Embedding Medium ◽

Low Temperature Microscopy

The unusual title of this short paper and its accompanying tutorial is deliberate, because the intent is to investigate the effectiveness of low temperature microscopy and analysis as one of the more significant elements of the less interventionist procedures we can use to prepare, examine and analyse hydrated and organic materials in high energy beam instruments. The promises offered by all these procedures are well rehearsed and the litany of petitions and responses may be enunciated in the following mantra.Vitrified water can form the perfect embedding medium for bio-organic samples.Frozen samples provide an important, but not exclusive, milieu for the in situ sub-cellular analysis of the dissolved ions and electrolytes whose activities are central to living processes.The rapid conversion of liquids to solids provides a means of arresting dynamic processes and permits resolution of the time resolved interactions between water and suspended and dissolved materials.The low temperature environment necessary for cryomicroscopy and analysis, diminish, but alas do not prevent, the deleterious side effects of ionizing radiation.Sample contamination is virtually eliminated.

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Utilisation of High-Energy Heat Sources in Magnesium Alloy Surface Layer Treatment

Archives of Metallurgy and Materials ◽

10.2478/amm-2013-0047 ◽

2013 ◽

Vol 58 (2) ◽

pp. 619-624 ◽

Cited By ~ 2

Author(s):

M. Szafarska ◽

J. Iwaszko ◽

K. Kudła ◽

I. Łegowik

Keyword(s):

Surface Layer ◽

Magnesium Alloy ◽

Physicochemical Properties ◽

Treatment Effectiveness ◽

High Energy ◽

Alloy Surface ◽

Heat Sources ◽

X Ray ◽

Additional Equipment ◽

Alloy Surface Layer

The main aim of the study was the evaluation of magnesium alloy surface treatment effectiveness using high-energy heat sources, i.e. a Yb-YAG Disk Laser and the GTAW method. The AZ91 and AM60 commercial magnesium alloys were subject to surface layer modification. Because of the physicochemical properties of the materials studied in case of the GTAW method, it was necessary to provide the welding stand with additional equipment. A novel two-torch set with torches operating in tandem was developed within the experiment. The effectiveness of specimen remelting using a laser and the GTAW method was verified based on macro- and microscopic examinations as well as in X-ray phase analysis and hardness measurements. In addition, the remelting parameters were optimised. The proposed treatment methodology enabled the achieving of the intended result and effective modification of a magnesium alloy surface layer.

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Fabrication of circular cooling channels by cold metal transfer based wire and arc additive manufacturing

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/0954405421995613 ◽

2021 ◽

pp. 095440542199561

Author(s):

Shaohua Han ◽

Zhongzhong Zhang ◽

Pengxiang Ruan ◽

Shiwen Cheng ◽

Dingqi Xue

Keyword(s):

Additive Manufacturing ◽

High Energy ◽

Cooling Effect ◽

High Deposition Rate ◽

Cooling Channel ◽

Conformal Cooling Channel ◽

Conformal Cooling ◽

Energy Beam ◽

Cooling Channels ◽

Straight Line

Additive manufacturing has been proven to be a promising technology for fabricating high-performance dies, molds, and conformal cooling channels. As one of the manufacturing methods, wire and arc additive manufacturing displays unique advantages of low cost and high deposition rate that are better than other high energy beam-based ones. This paper presents a preliminary study of fabricating integrated cooling channels by CMT-based wire and arc additive manufacturing process. The deposition strategies for fabricating circular cross-sectional cooling channels both in conformal and straight-line patterns have been investigated. It included optimizing the welding torch angle, fabricating the enclosed semicircle structure and predicting the collision between the torch and constructed part. The cooling effect test was also conducted on both the conformal cooling channel and straight-line cooling channel. The results affirmed a higher cooling efficiency and better uniform cooling effect of the conformal cooling channel than straight-line cooling channel.

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