Fretting Wear Behavior Research Articles

Fretting wear behavior test and numerical simulation of Inconel 690 alloy

ABSTRACT A steam generator heat transfer tube is important for energy exchange between the primary circuit and secondary circuit . The changes in friction and wear properties of Inconel 690 alloy and 403 stainless-steel anti-vibration strips in different media (air, deionized water, and boric acid solution) were compared and analyzed. Friction and wear tests were conducted in different media environments and under different loads, and finite element simulation was performed in different media environments.Results show that the main wear mechanisms in the air are delamination wear and oxidation friction. The oxygen content in the water is reduced, and the oxide formed is reduced. Because the solution replaces the abrasive particles to form the third body, which can reduce friction and lubricate, the abrasive particles and abrasive particles can be easily removed or dissolved. The wear mechanism in a water environment is delamination wear and abrasive wear. In boric acid, a passive film is formed on the contact wear surface of the Inconel 690 alloy after the previous fretting wear. The passivation film is worn first in the next fretting wear, which slows down wearing. The wear mechanism in a boric acid environment primarily includes abrasive wear and corrosion wear.

Fretting wear behavior of aluminum coatings

The aluminum bronze coating is a type of soft solid lubricant film with excellent performance. In this work, to improve the wear resistance and tribological behavior of the aluminum alloy, the aluminum bronze coatings were prepared on aluminum alloy substrates using the High- Velocity Oxygen Fuel (HVOF) system. Fretting wear tests were performed on the coatings at 200 °C with different frequencies to analyze the wear behavior. The worn surface was characterized by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that as the frequency increased from 5 Hz to 15 Hz, the coefficient of friction increased from 0.653 to 0.929. It then decreased to 0.890 at 20 Hz. There was an overall trend of the coefficient of friction increasing and then decreasing. The worn surface’s morphology changed from pits to bulges. At a low frequency, the wear mechanism was abrasive wear with delamination. As the frequency increased, adhesive wear was observed and gradually became the dominant wear form. Oxidation occurred on the surface of the worn tracks caused by the high temperature and thermal effect of high-frequency micromotion. Due to the intensification of the oxidation phenomenon, oxidation films formed on the worn surface. The wear rate of the coating was significantly reduced. The oxide was identified as mainly CuO and Cu2O. The presented results confirmed that the aluminum bronze coating fabricated via HVOF exhibited a great resistance performance even at a high frequency.

Fretting wear behavior of Zr alloy cladding tube mated with Zr alloy dimple under mixed fretting regime in simulated primary water of PWR

The fretting wear behavior of Zr alloy cladding tube under mixed fretting regime in a high-temperature pressurized water was investigated. The main wear mechanism is adhesive wear, with characters of small-scale delamination at the center of worn area and serious delamination on the worn edge. A long crack throughout the worn area and other cracks propagated towards the substrate are observed. The cross-sectional microstructure of worn area can be divided into a thick third-body layer, thin inner oxide layer and thick tribologically transformed structure layer, and their formation mechanisms are analyzed in detail. Finally, the mixed fretting regime process and the microstructural evolution during fretting wear are discussed.

Friction and wear behavior of multiple steel wires with different corrosion extents under different lubrication conditions

Corrosion and wear of the steel wires are two major factors in the failure of wire ropes and can greatly reduce their service life as well as the reliability of mine hoists. In this paper, to study the fretting wear behavior of multiple wires with different extents of corrosion under different lubrication conditions, fretting wear tests on corroded wires were conducted on a homemade testing apparatus. The results show that corrosion and lubrication had great influence on coefficient of friction (COF) and fretting state. In addition, the wear resistance of steel wire decreased with increasing corrosion extent. The application of lubricant is beneficial. It could significantly reduce the overall specific wear rate and reduce the difference in degree of wear due to corrosion. In two lubricants specially used for mining wire ropes, lubricating grease (IRIS-400 M) had better anti-wear effect than lubricating oil (IRIS-550A). Furthermore, lubrication condition and corrosion degree affected the wear mechanism between steel wires. This study can provide basic data for the safe use and maintenance of wire rope.

Investigation on fretting wear of NiCrAlY coatings at elevated temperature

Tribological properties of MCrlAlY (M = Ni, Co, or Ni and Co) coatings are well established under sliding conditions. However, the tribological properties of MCrAlY coatings under fretting conditions, typically encountered in blade-disk dovetail connection of aero engines, are yet to be further studied. The present study aims to investigate the elevated-temperature fretting wear behaviors and mechanisms of a NiCrAlY coating deposited on a γ-TiAl substrate. Scanning electron microscope, energy dispersive spectrometer, and Raman spectrometer were utilized to study the wear scars and tribolayers. Transmission electron microscope and nanoindentation tests were utilized to elucidate the structural and mechanical properties of the tribolayers. The results revealed that, large areas of sea-shape tribolayers formed on the NiCrAlY coating and resulted in the low wear rate and friction coefficient. While for the γ-TiAl substrate, small areas of island-shape tribolayers formed, and insufficient to protect the alloy from severe abrasive wear, delamination, and adhesive wear. The formation of the sea-shape tribolayers was found to be derived from the high diffusion coefficients in the oxides. In addition, the wear of the counterpart nickel alloy was not aggravated with the NiCrAlY coating, since sea-shape tribolayers also formed on the counterpart.

Directional fretting wear behaviour of constrained groove pressed aluminium sheet

Wear behavior of the constrained groove pressed (CGP) aluminium (Al) sheet was examined along both the longitudinal as well as transverse direction using fretting wear tester. The results unequivocally showed a significant diminution (up to 1.2 times for one pass) in the coefficient of friction (COF) which leads to significant improvement in the wear resistance after each pass of CGP when compared to the as-received (AR) sample. Subsequently, wear rate in the CGP processed sample was found to be lower along the transverse direction (∼ 0.38 ± 0.08 ×102 µm3/N.mm) compared to that in the longitudinal direction (∼ 0.87 ± 0.12 ×102 µm3/N.mm) for one pass sample. Along longitudinal direction the major wear mechanism is discerned to be severe abrasion followed by crater formation in the samples with lower strain (i.e. 1 pass), however, it is delamination followed by dense tribolayer formation in the highly strained sample along transverse direction. Increasing fraction of oxygen content in energy dispersive spectroscopy result support the formation of dense tribolayer along transverse direction which attribute to formation of protective layer in the wear scar. The substantial decrement in the wear volume and hence wear rate after severe deformation is credited to the significant strain imposed in the sample, which leads to significant hardness up to ∼ 1.5 times for 3 pass CGP (44.5 VHN) due to the grain refinement from AR to 3 pass CGP i.e., ∼ 21.64 µm to ∼ 5.60 µm. Therefore, effect of grain refinement on the mechanical as well as wear properties with CGP on Al substrate has also been established.

Effects of frequency on the fretting wear behavior of aluminum bronze coatings

The aluminum bronze coating is a type of soft solid lubricant film with excellent performance. In this work, to improve the wear resistance and tribological behavior of the aluminum alloy, the aluminum bronze coatings were prepared on aluminum alloy substrates using the High-Velocity Oxygen Fuel (HVOF) system. Fretting wear tests were performed on the coatings at 200 °C with different frequencies to analyze the wear behavior. The worn surface was characterized by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that as the frequency increased from 5 Hz to 15 Hz, the coefficient of friction increased from 0.653 to 0.929. It then decreased to 0.890 at 20 Hz. There was an overall trend of the coefficient of friction increasing and then decreasing. The worn surface's morphology changed from pits to bulges. At a low frequency, the wear mechanism was abrasive wear with delamination. As the frequency increased, adhesive wear was observed and gradually became the dominant wear form. Oxidation occurred on the surface of the worn tracks caused by the high temperature and thermal effect of high-frequency micromotion. Due to the intensification of the oxidation phenomenon, oxidation films formed on the worn surface. The wear rate of the coating was significantly reduced. The oxide was identified as mainly CuO and Cu2O. The presented results confirmed that the aluminum bronze coating fabricated via HVOF exhibited a great resistance performance even at a high frequency.

Effect of ultrasonic nanocrystal treatment combined with nitriding process on fretting wear behavior of textured 20CrMoH steel

Individual and synergy effects of laser surface texturing (LST) followed by plasma nitriding (PN) and surface ultrasonic nanocrystal technology (SUNT) on fretting wear behaviors of 20CrMoH steel were systematically investigated at various loads and lubrication conditions. Results indicated that the combined treated (LST + PN + SUNT) 20CrMoH steel got the lowest surface roughness Ra value of 0.46 μm, the highest surface microhardness of 940 HV0.2, and the maximum residual compressive stress (RCS) value of −750 MPa. Consequently, the best fretting wear resistance was obtained by the combined treated 20CrMoH steel. Wear loss of untreated specimen reduced by 131 % after the combined treatment. The predominant wear mechanisms of the untreated, PN treated and LST + PN treated 20CrMoH steel under dry friction were oxidation wear and delamination. Besides, Oxidation and adhesion occurred for the combined treated specimen in dry friction. Especially, texture, residual stress and microhardness are key factors enhancing the anti-wear resistance.

The transformation of fretting corrosion mechanism of zirconium alloy tube mating with 304 stainless steel in high temperature high pressure water

Studying the fretting wear mechanism of zirconium alloy in high temperature high pressure water is of great importance for understanding the failure behavior of fuel assembly. In this work, the tangential fretting wear of zirconium alloy tube at different displacement amplitudes (40 µm and 80 µm) and normal forces (6 N and 12 N) was investigated in high temperature high pressure water. The results show that the wear depth and wear volume of zirconium alloy tested at 6 N-80 µm are the highest among all the tests. When the testing condition is 6 N-80 µm, the fretting is located in the gross slip regime. Oxidation and abrasive wear dominate the fretting wear behavior. The increase in normal force and decrease in displacement reduces the relative sliding distance between the contact interfaces, which reduces the ejection of wear debris and changes the wear mechanism. When the test conditions are 6 N-40 µm and 12 N-40 µm, the fretting regime is located in the partial slip regime, and the dominant wear mechanisms are adhesive wear and oxidation. Under the synergistic effect of mechanical wear and high-temperature water corrosion, a dual-layer structure oxide scale is formed on the worn area. The mixed oxide layer with loose and porous structure is formed by the accumulation of granular wear debris, while the dense inner oxide layer is mainly formed by oxidation of the matrix alloy. Fretting wear accelerates material corrosion by wear debris refinement and cracking. The integrity of the oxide layer is negatively correlated with its thickness. As the thickness of the oxide layer increases, more cracks can be observed in the oxide layer.

Effect of contact misalignment on fretting wear behavior between fuel cladding and Zr-4 grid

Cladding fuel rods supported in grids are important core components in pressurized water nuclear reactors. Small rod-to-grid misalignments can occur during the core manufacturing process. The presence of tilted contacts may promote fretting wear damage between claddings and grids by flow-induced vibrations (FIV). In this study, the influence of tilted contacts on the fretting wear between fuel rod cladding and a Zr-4 alloy grid, caused by deviations during assembly, was analyzed and discussed. A 3D finite element model was set up to obtain the stress state on the contact interface between the cladding and grid under different included angles. Results show that the wear morphology and profile presented evident dependence on the included angle. The change of the included angle between the cladding and grid changes the contact form of the two, leading to changes in the local stress and contact area in the interface. This process ultimately changes the thickness of the wear debris accumulation layer (WDL).

Fretting wear behavior of Inconel 718 alloy manufactured by DED and treated by UNSM

Alloy 718 is commonly used in the maritime and aerospace industries due to its strength and durability, particularly in engine rotating components such as disks, fan blades, and high-pressure compressors. As a new type of 3D printing technology, directed energy deposition (DED) can employ lasers to melt metal powders or wires to fabricate arbitrary-shaped workpieces directly from customized data, thereby making machining more synergistic and intuitive. However, the surface properties of the DED-printed alloy 718 samples, such as surface roughness and wear resistance, are typically subpar. By introducing severe plastic deformation to the near-surface, ultrasonic nanocrystal surface modification (UNSM) can be used as a post-processing method and results in altered properties. The uniaxial tensile test reveals that the UNSM-treated alloy 718 exhibits a higher mechanical property. Moreover, using a fretting test rig in accordance with the cylinder-on-plane agreement, a higher wear resistance for UNSM-treated alloy 718 is observed. This study employs the finite element method to fully comprehend the effect of UNSM on wear performance. The fretting wear process of Inconel 718 alloy is established using an energy-based finite element model. Considering the severe practical scenarios, the Johnson–Cook constitutive model is implemented, with the linear isotropic hardening model capturing the plastic behavior. In comparison to experimental measurements, the finite element results demonstrate unprecedented wear loss consistency with an error of less than 2%. Therefore, we conclude that the finite element model built in this study exhibits a high accuracy and can be used to analyze the effect of UNSM on fretting wear behavior. According to finite element analysis, as the normal load increases, the improvement in wear resistance induced by UNSM decreases. Given that the finite element model is based on the energy method, the effects of coefficient of friction (COF) and wear coefficient modified by UNSM are investigated separately. According to the findings, the UNSM-modified COF and wear coefficient play a significant role in determining the wear characteristics. Due to the removal of a substantial amount of material from the central area of the alloy 718 surface by wear, it is also possible to observe that severe plastic strains are primarily concentrated at the edges of the wear scars.

Effect of surface modification technology on mechanical properties and dry fretting wear behavior of Inconel 718 alloy fabricated by laser powder-based direct energy deposition

Ultrasonic nanocrystal surface modification (UNSM) technique was applied to Inconel 718 alloy fabricated by laser powder-based direct energy deposition (LP-DED). The main aim of this study is to improve the mechanical properties and fretting wear behavior. No significant difference in surface roughness between the polished and UNSM-treated samples was made on purpose to avoid the effect of surface roughness on fretting wear behavior. The hardness and residual stress of the polished samples were increased after UNSM technique. Dry fretting wear behavior was evaluated using a ball-on-disk configuration at 24 and 60 °C. The results showed that the fretting wear resistance of the polished samples at both temperatures was enhanced, whereas an increase in temperature further enhanced the fretting wear resistance. In addition, possible factors influencing the enhancement in fretting wear behavior after UNSM technique in terms of fretting wear mechanisms and potential application were discussed.

Effect of Normal Force on Fretting Wear Behavior of Zirconium Alloy Tube in Simulated Primary Water of PWR

Effect of Normal Force on Fretting Wear Behavior of Zirconium Alloy Tube in Simulated Primary Water of PWR

Fretting wear behaviour of ultrafine-grained copper produced by cryogenic temperature extrusion machining

Cryogenic temperature extrusion machining (CT-EM), as a new process, was first applied for preparing ultrafine-grained (UFG) copper strips. The microstructure evolution and mechanical properties (hardness and fretting wear) were characterised by electron backscatter diffraction and transmission electron microscopy methods. Refined grains (450 nm) and high dislocation density could be obtained by CT-EM because of effectively suppressing heat generation and the annihilation of dislocations. As a result, the CT-EM sample exhibited enhanced fretting wear properties, e.g. a much lower friction coefficient (reducing 0.1–0.2) and a lower wear loss (decreasing 32–45%) were achieved due to its enhanced hardness and refined microstructure. In-depth, the delamination and oxidation wear proved to be the primary wear mechanism of the CT-EM sample under dry wear conditions.

Establishment of fretting maps of Zr alloy cladding tube mated with Zr alloy dimple in simulated primary water of pressurized water reactor

Fretting maps of Zr alloy tube under grid-to-rod configuration in high temperature pressurised water were established. Running condition fretting map shows three fretting regimes, namely, partial slip regime, mixed fretting regime and gross slip regime. According to material response fretting map, the wear mechanism under partial slip regime is adhesive wear with the character of delamination of local regions, both adhesive wear and cracking are found for mixed fretting regime, while abrasive wear and severe delamination for gross slip regime. Compared with the results at room temperature, the mixed fretting regime range increases obviously at high temperature, while friction coefficient at high temperature is lower. In addition, fretting wear behaviour of Zr alloy tube under different fretting regimes is discussed.

Study on the fretting wear behavior over a wide temperature range of an Inconel 718 superalloy deposited by laser cladding

Fretting tests were performed on an Inconel 718 superalloy against GCr15 steel in a range of 25 ℃ < T < 400 ℃ to investigate the wear mechanism of the laser cladding-deposited Inconel 718 superalloy over a wide temperature range. The results show that when the displacement amplitude was 15 μm, the fretting was running in a partial slip regime (PSR), and the wear damage mainly showed elastic–plastic deformation, fatigue wear and abrasive wear. When the displacement amplitude increased to 100 μm, fretting occurred in a mixed slip regime (MSR) and gross slip regime (GSR). With continuous fretting wear, the dissipated energy of the material decreased gradually with increasing temperature in a stable state. The wear damage was mainly combined with fatigue wear and peeling. When the temperature was 100 ℃, the coefficient of friction (COF) value in the stable state was large. As the temperature increased, adhesive wear and oxidative wear gradually predominated in the fretting tests. The effect of high temperature easily formed an adhesive layer on the worn surface with wear reduction, especially at a high displacement amplitude.

Fretting wear properties and microstructure evolution in micro-arc oxidation bioceramic coating pretreated using laser remelting

To improve fretting wear resistance, bio-ceramic coatings were successfully fabricated on TC6 alloy substrates using a combination of laser remelting (LRM) and micro-arc oxidation (MAO). The surface morphology, composition, and residual stress distribution of the coatings were characterized using scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, ultra-deep field three-dimensional microscopy, and X-ray stress analysis. The influence of LRM pretreatment on the fretting wear behaviour of MAO bioceramic coatings was investigated. The LRM pre-treatment did not change the phase composition of the MAO coatings, which were all composed of Al2TiO5, rutile TiO2, and anatase TiO2 phases. However, increasing the content of the rutile TiO2 phase from 68 to 89% improved the uniformity and density of the coatings and decreased the porosity by 2.8%. The fretting wear test results showed that the LRM pretreated MAO coating exhibited the best performance against fretting wear in a simulated body fluid environment. In this case, the fretting wear mechanism was attributed to slight delamination and fatigue wear.

Effect of coating prepared using CuNiIn mixed with graphite and MoS2 on fretting wear behaviour of Ti6Al4V

• Graphite and CuNiIn were plasma sprayed onto Ti6Al4V to get self-lubricating coating. • Addition of graphite to CuNiIn powder reduced the friction coefficient in fretting. • Presence of MoS2 at the contact surface further reduced the friction coefficient. • Effect of MoS2 at the contact surface was significant in CuNiIn + Graphite coating. In the present study, solid graphite was mixed with CuNiIn powder and plasma sprayed onto Ti6Al4V to develop a self-lubricating coating (CuNiIn + Gr). Fretting wear experiments were done at room temperature on uncoated Ti6Al4V samples and samples coated with CuNiIn + Gr composite powder and CuNiIn powder. The counterbody used was alumina ball. Inclusion of graphite in CuNiIn reduced the friction coefficient owing to graphite acting as a self-lubricant. To study the effect of solid lubricant MoS 2 , some tests were done after applying MoS 2 on the surface of the samples. The presence of MoS 2 reduced the friction coefficient in all samples. The reduction was more in CuNiIn + Gr coated samples, which can be related to the synergetic effect of both the solid lubricants.

Effect of Graphene Sheets Embedded Carbon Films on the Fretting Wear Behaviors of Orthodontic Archwire-Bracket Contacts.

Carbon films were fabricated on the orthodontic stainless steel archwires by using a custom-designed electron cyclotron resonance (ECR) plasma sputtering deposition system under electron irradiation with the variation of substrate bias voltages from +5 V to +50 V. Graphene sheets embedded carbon (GSEC) films were fabricated at a higher substrate bias voltage. The fretting friction and wear behaviors of the carbon film-coated archwires running against stainless steel brackets were evaluated by a home-built reciprocating sliding tribometer in artificial saliva environment. Stable and low friction coefficients of less than 0.10 were obtained with the increase of the GSEC film thickness and the introduction of the parallel micro-groove texture on the bracket slot surfaces. Particularly, the GSEC film did not wear out on the archwire after sliding against three-row micro-groove textured bracket for 10,000 times fretting tests; not only low friction coefficient (0.05) but also low wear rate (0.11 × 10−6 mm3/Nm) of the GSEC film were achieved. The synergistic effects of the GSEC films deposited on the archwires and the micro-groove textures fabricated on the brackets contribute to the exceptional friction and wear behaviors of the archwire-bracket sliding contacts, suggesting great potential for the clinical orthodontic treatment applications.

Finite element simulation of fretting wear behaviors under the ball-on-flat contact configuration

Finite element method (FEM) has been extensively applied in predicting fretting wear due to its advantage in solving problems like non-linearity of boundary conditions. This work combines FEM with energy model to simulate fretting wear under the ball on flat contact configuration. The simulation model was firstly verified experimentally. Then the mechanical, friction and wear behaviors were analyzed in detail. The results indicate that in PSR, the cross-sectional profiles of worn surface transform from “W” to “U” shape along the fretting direction, while in GSR they keep the “U” shape. The normal load and amplitude have a combined effect on the contact pressure and shear stress, and then determine the kinetic behavior, wear behavior and evolution of worn surfaces.