scholarly journals The Effect of TiN and DLC Anti-Wear Coatings on the Tribofilm Formation and Frictional Heat Phenomena in Coated Metals vs. WC-Co

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3342
Author(s):  
Magdalena Łępicka ◽  
Yurii Tsybrii ◽  
Daniel Kiejko ◽  
Karol Golak
Keyword(s):  
Frictional Heating ◽  
Sample Surface ◽  
Metallic Substrate ◽  
Frictional Heat ◽  
Tin Coating ◽  
Two Phase ◽  
Antifriction Properties ◽  
Rapid Temperature ◽  
Wear Coatings ◽  
Sliding Distance

The aim of this work was to study the effect of anti-wear coatings on the selected frictional phenomena, i.a., frictional heating and tribofilm formation, of model tribological pairs. For this purpose, three popular metallic substrate materials were selected: AISI 316L and AISI 440B stainless steels, as well as Ti6Al4V two-phase titanium alloy. The substrates were tested in the dry sliding conditions in three states: uncoated, as well as titanium nitride (TiN) or diamond-like-carbon (DLC) coated. According to the results provided, under applied frictional conditions TiN coating, even if it is worn off the sample surface, contributes to excessive frictional heating of a tribological pair by altering the tribofilm formation. The analysis also showed that in some tribological pairs, rapid temperature alteration of a counter sample can be used to approximate the sliding distance after which the TiN coating becomes worn off. On the contrary, in all pairs tested, the DLC film became locally damaged, but it sustained its antifriction properties, contributing to low coefficients of friction (COFs) and the lowest frictional temperatures observed.

An Adaptive EFG-FE Computational Model for Thermal Elasto-Plastic Frictional Contact Problems

2008 ◽  
Vol 33-37 ◽  
pp. 821-826
Author(s):  
Zheng Zhang ◽  
Geng Liu ◽  
Tian Xiang Liu
Keyword(s):  
Frictional Heating ◽  
Contact Problems ◽  
Coupling Model ◽  
Adaptive Refinement ◽  
Frictional Heat ◽  
Plastic Behavior ◽  
Initial Stiffness ◽  
Gradient Based ◽  
Local Adaptive Refinement ◽  
The Cost

An adaptive meshless element-free Galerkin-finite element (EFG-FE) coupling model for thermal elasto-plastic contact problems is developed to investigate the influences of the steady-state frictional heating on the contact performance of two contacting bodies. The thermal elasto-plastic contact problems using the initial stiffness method is presented. The local adaptive refinement strategy and the strain energy gradient-based error estimation for EFG-FE coupling method are combined. The adaptive meshless model takes into account the temperature variation, micro plastic flow, and the coupled thermo-elasto-plastic behavior of the materials, considering the strain-hardening property of the materials and temperature-dependent yield strength. The adaptive model is verified through the contact analysis of a cylinder with an elasto-plastic plane. The thermal effects on the contact pressure, stresses distributions with certain frictional heat inputs are studied. The results show that the accuracy of the solutions from the adaptive refinement model is satisfactory but the cost of the CPU time is much less than that for the uniform refinement calculation.

Numerical investigation of frictional heating effect on the earthquake faulting based on the Ruina- and Chester-Higgs- models

2020 ◽  
Author(s):  
Yaqi Gao ◽  
Baoping Shi
Keyword(s):  
Temperature Effect ◽  
Temporal Evolution ◽  
Initial Conditions ◽  
Frictional Heating ◽  
Higgs Model ◽  
Fault System ◽  
Frictional Heat ◽  
Recurrence Time ◽  
Generation Model ◽  
Frictional Strength

<p>Rate- and state-dependent friction laws (RSF laws) are empirical laws derived from laboratory experiments related to rock friction. They have been used to quantitatively describe complex fault friction processes. With a combination of the RSF laws and the McKenzie-Brune frictional heat generation model, we have studied the effects of frictional heating processs on the fault strength variation and temporal evolution of temperature based on the spring-slider-fault system subjected to Ruina and Chester-Higgs RSF laws. The system equations are solved efficiently by Dormand-Prince method with adaptive steps. First, with a comparison to the Ruina- model in which the temperature effect due to frictional heating on frictional strength is neglected, the numerical results show that the fault will be unstable slightly earlier for the Chester-Higgs- model in which the temperature effect due to frictional heating on frictional strength is taken into consideration, which indicates that the rise of temperature caused by frictional heating can lead to a slight time advance of fault instability. Second, by contrast with Ruina- model, the frictional strength will keep a little bit higher for the Chester-Higgs- model when the fault sliding at high speed, indicating that frictional heat can strengthen faults to a certain extent. Third, the simulation results also suggest that, at the same rupture velocity, the temperature change for the Chester-Higgs- model is much smaller than that given by the Ruina- model, indicating that frictional heat can also restrain the sharp rise of temperature on fault surface. In addition, under the same parameters and initial conditions, the seismic occurrence time giving by the Chester-Higgs- model is obviously shorter than that by the Ruina- model, indicating that a significant effect of friction heating generated on entire fault temporal evolution could greatly reduce the seismic recurrence time. Correspondingly, both static stress drop and total slip resulted from the Chester-Higgs- model is also smaller than that from the Ruina- model, respectively.</p>

Surface Normal Thermoelastic Displacement in Moving Rough Contacts

2003 ◽  
Vol 125 (4) ◽  
pp. 862-868 ◽  
Author(s):  
Shuangbiao Liu ◽  
Qian Wang ◽  
Stephen J. Harris
Keyword(s):  
Contact Pressure ◽  
Mutual Influence ◽  
Frictional Heating ◽  
Numerical Procedure ◽  
Contact Problems ◽  
Frictional Heat ◽  
Elastic Displacement ◽  
Surface Normal ◽  
Moving Bodies ◽  
Thermoelastic Displacement

Computing the thermoelastic displacement of three-dimensional stationary or moving bodies subject to frictional heating is an essential numerical procedure for the complex modeling of the contact of tribological components. Surface Roughness inevitably causes the irregularity of the frictional heat distribution, and thus complicates the process of the numerical simulation of contact problems. The surface normal thermoelastic displacement has been studied in previous papers for either stationary bodies with irregularly distributed heat or moving bodies with regularly distributed heat. In this work, irregularly distributed frictional heat is applied on the surface of a moving body. Temperature and surface normal thermoelastic displacement are solved by using an efficient numerical procedure involving the discrete convolution and fast Fourier transform algorithm and frequency response functions. The thermoelastic displacement due to frictional heat that is proportional to the contact pressure is comparable to the elastic displacement caused by the contact pressure and is not sensitive to the roughness texture. The transient performance of multiple heat sources with different shapes, as well as the mutual influence, is also studied.

scholarly journals Mass and enthalpy budget evolution during the surge of a polythermal glacier: a test of theory

2019 ◽  
Vol 65 (253) ◽  
pp. 717-731 ◽  
Author(s):  
Douglas I. Benn ◽  
Robert L. Jones ◽  
Adrian Luckman ◽  
Johannes J. Fürst ◽  
Ian Hewitt ◽  
...  
Keyword(s):  
Frictional Heating ◽  
Drainage System ◽  
Frictional Heat ◽  
Balance Theory ◽  
Ice Thickness ◽  
Resolution Time ◽  
Geothermal Heat ◽  
Ice Surface ◽  
Air Temperatures ◽  
Polythermal Glacier

AbstractAnalysis of a recent surge of Morsnevbreen, Svalbard, is used to test predictions of the enthalpy balance theory of surging. High-resolution time series of velocities, ice thickness and crevasse distribution allow key elements of the enthalpy (internal energy) budget to be quantified for different stages of the surge cycle. During quiescence (1936–1990), velocities were very low, and geothermal heat slowly built-up enthalpy at the bed. Measurable mass transfer and frictional heating began in 1990–2010, then positive frictional heating-velocity feedbacks caused gradual acceleration from 2010 to 2015. Rapid acceleration occurred in summer 2016, when extensive crevassing and positive air temperatures allowed significant surface to bed drainage. The surge front reached the terminus in October 2016, coincident with a drop in velocities. Ice plumes in the fjord are interpreted as discharge of large volumes of supercooled water from the bed. Surge termination was prolonged, however, indicating persistence of an inefficient drainage system. The observations closely match predictions of the theory, particularly build-up of enthalpy from geothermal and frictional heat, and surface meltwater, and the concomitant changes in ice-surface elevation and velocity. Additional characteristics of the surge reflect spatial processes not represented in the model, but can be explained with respect to enthalpy gradients.

scholarly journals Carbon Coatings Deposited on Prosthodontic Ni-Cr Alloy

2021 ◽  
Vol 11 (10) ◽  
pp. 4551
Author(s):  
Zofia Kula ◽  
Michael Semenov ◽  
Leszek Klimek
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Bacterial Adhesion ◽  
Sample Surface ◽  
Metallic Substrate ◽  
Raman Spectrometry ◽  
Carbon Coatings ◽  
Corrosion Tests ◽  
Structural Tests ◽  
Number Of Bacteria

The study discusses the results of investigations conducted on carbon coatings applied on a prosthodontic alloy Ni-Cr. Carbon coatings with the thickness of about 1000 nm were deposited by means of the RF PACVD method with a titanium interlayer applied by magnetron spray dispersion. The coatings underwent microscopic examinations, as well as structural tests with the use of Raman spectrometry, investigations of mechanical properties, adhesion and corrosion tests; also, the bacterial adhesion to the sample surface was determined. It can be inferred from the performed studies that the obtained carbon coatings exhibit mechanical properties which allow them to be used for prosthodontic elements. The coatings’ adhesion to the metallic substrate made of Ni-Cr alloy equaled about 150 mN. The examined coatings clearly improve the corrosion resistance and reduce the number of bacteria adhering to the sample surfaces. Taking all this into account, it can be stated that carbon coatings can be potentially applied to protect metal prosthetic restorations.

scholarly journals Scanning 3DXRD Measurement of Grain Growth, Stress, and Formation of Cu6Sn5 around a Tin Whisker during Heat Treatment

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 446 ◽  
Author(s):  
Johan Hektor ◽  
Stephen Hall ◽  
N. Henningsson ◽  
Jonas Engqvist ◽  
Matti Ristinmaa ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Boundaries ◽  
Grain Growth ◽  
Hydrostatic Stress ◽  
Coincidence Site Lattice ◽  
Sample Surface ◽  
Growth Stress ◽  
Projection Algorithm ◽  
Tin Whisker ◽  
Tin Coating

The 3D microstructure around a tin whisker, and its evolution during heat treatment were studied using scanning 3DXRD. The shape of each grain in the sample was reconstructed using a filtered-back-projection algorithm. The local lattice parameters and grain orientations could then be refined, using forward modelling of the diffraction data, with a spatial resolution of 250 n m . It was found that the tin coating had a texture where grains were oriented such that their c-axes were predominantly parallel to the sample surface. Grains with other orientations were consumed by grain growth during the heat treatment. Most of the grain boundaries were found to have misorientations larger than 15 ∘ , and many coincidence site lattice (CSL) or other types of low-energy grain boundaries were identified. None of the grains with CSL grain boundaries were consumed by grain growth. During the heat treatment, growth of preexisting Cu6Sn5 occurred; these grains were indexed as a hexagonal η phase, which is usually documented to be stable only at temperatures exceeding 186 ∘ C . This indicates that the η phase can exist in a metastable state for long periods. The tin coating was found to be under compressive hydrostatic stress, with a negative gradient in hydrostatic stress extending outwards from the root of the whisker. Negative stress gradients are generally believed to play an essential role in providing the driving force for diffusion of material to the whisker root.

Thermal Effects on Elasto-Plastic Contacts between Rough Surfaces

2006 ◽  
Vol 532-533 ◽  
pp. 801-804
Author(s):  
Geng Liu ◽  
Tian Xiang Liu ◽  
Qin Xie
Keyword(s):  
Steady State ◽  
Thermal Effects ◽  
Rough Surfaces ◽  
Frictional Heating ◽  
Stress Fields ◽  
Frictional Heat ◽  
Plastic Behavior ◽  
Contact Conditions ◽  
Real Area Of Contact ◽  
Real Area

The effects of the steady-state frictional heating on the contact performance of surface asperities and subsurface stress fields between rough surfaces are investigated in this paper. The asperity distortion caused by the temperature variation in a tribological process, micro plastic flow of surface asperities, and the coupled thermo-elasto-plastic behavior of the materials, with and without considering the strain-hardening property of the materials are studied. In addition, the contact pressure, real area of contact, and average gap of real rough surface with different frictional heat inputs under the thermal elasto-plastic contact conditions are analyzed and discussed.

scholarly journals Frictional Heating with Time-Dependent Specific Power of Friction

2017 ◽  
Vol 11 (2) ◽  
pp. 111-115 ◽  
Author(s):  
Katarzyna Topczewska
Keyword(s):  
Time Distribution ◽  
Frictional Heating ◽  
Heat Fluxes ◽  
Time Dependent ◽  
Frictional Heat ◽  
Specific Power ◽  
Dimensionless Temperature ◽  
Brake Disc ◽  
Dimensionless Form ◽  
Spatio Temporal

AbstractIn this paper analytical solutions of the thermal problems of friction were received. The appropriate boundary-value problems of heat conduction were formulated and solved for a homogeneous semi–space (a brake disc) heated on its free surface by frictional heat fluxes with different and time-dependent intensities. Solutions were obtained in dimensionless form using Duhamel's theorem. Based on received solutions, evolution and spatial distribution of the dimensionless temperature were analyzed using numerical methods. The numerical results allowed to determine influence of the time distribution of friction power on the spatio-temporal temperature distribution in brake disc.

The Effects of Ion Sputtering on Dentin and its Relation to Depth Profiling

1994 ◽  
Vol 73 (8) ◽  
pp. 1457-1461 ◽  
Author(s):  
R.G. Miller ◽  
C.Q. Bowles ◽  
P.L. Gutshall ◽  
J.D. Eick
Keyword(s):  
Auger Electron Spectroscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Adhesive Bonding ◽  
Surface Composition ◽  
Depth Profiling ◽  
Sample Surface ◽  
Ion Sputtering ◽  
Two Phase ◽  
Dentin Surface

Characterization of the dentin surface and the dentin/adhesive interface is fundamental to investigations concerning adhesive bonding to dentin. It has been shown that good adhesive bonding depends on both the structure and composition of the dentin surface. A combination of ion sputter etching and Auger electron spectroscopy can be used to obtain surface composition and elemental depth profiles at interfaces. This investigation was conducted to examine the changes induced in human dentin by ion sputtering under conditions commonly encountered during depth profiling. The sputtering was conducted with argon ions at 7.5 keV and an ion flux ranging from 1018-1019 ions/m 2s. The amount of material sputtered was calculated from profilometer measurements of the sample surface. The surface composition was monitored by Auger electron spectroscopy. The results indicate that, under these conditions, collagen was removed at a much faster rate than hydroxyapatite, causing the surface composition of dentin to change during the sputtering process. The sputter yields for hydroxyapatite and collagen were found to be 5 and 28 atoms/ion, respectively, at a sputter angle of 45°. At a sputter angle of 29°, the yields were 2 and 25 atoms/ion, respectively. Both the changes in composition of dentin and the measured sputter rates are in agreement with the behavior predicted by a theoretical model for two phase materials (Blaise, 1978; Blaise et al., 1978).

scholarly journals Pressure influence on heating of ventilating disc brakes for passenger cars

2020 ◽  
Vol 24 (1 Part A) ◽  
pp. 203-214 ◽  
Author(s):  
Nadica Stojanovic ◽  
Jasna Glisovic ◽  
Oday Abdullah ◽  
Ivan Grujic ◽  
Sasa Vasiljevic
Keyword(s):  
Combustion Engine ◽  
Frictional Heating ◽  
Applied Pressure ◽  
Element Model ◽  
Steering System ◽  
Frictional Heat ◽  
Maximum Temperature ◽  
Passenger Cars ◽  
Structural Parts ◽  
Braking Process

The braking system is one of the most important elements in vehicle systems from the aspect of vehicle safety, besides the steering system and the internal combustion engine. During the braking process, the disc and pads absorb a large amount of kinetic energy that converted to heat. Owing to this frictional heating, it is necessary to compute the temperature distribution that will be appeared during the braking process, which is the main goal of this research paper. There are many factors that can be influenced to the distribution of frictional heat generated. One of the significant factors is the applied pressure by the brake pad on the braking disc. The results proved that when increased the applied pressure then the frictional heat generated increased too. It was developed a new finite element model based on observed data from real vehicle. It was used ANSYS/WORKBENCH 14.5 software to perform the numerical analysis, module Transient Structural. Parts that are the most disposed to the thermal stress are braking pads. Also, it was found time period from 0 to 0.1 second is the most critical period during the whole braking period, because in this period, temperature rises rapidly, the maximum temperature occurred at 1.338 seconds, and after that it falls.

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