Surface Fatigue Wear Research Articles

Evolution of fretting wear behavior of zirconium alloy cladding tube under gross slip regime in simulated primary water of pressurized water reactor

The evolution of fretting wear behavior of zirconium alloy cladding tubes mated with dimples under the gross slip regime (GSR) was investigated. The findings revealed that the primary wear mechanisms under GSR were delamination, surface fatigue wear and abrasive wear, and the fretting damage rate mainly depends on delamination. The cross-sectional microstructure of the worn area could be divided into the third-body layer, tribologically transformed structure layer, and general deformation layer, with their formation mechanisms analyzed. Furthermore, the mechanism of wear-induced grain refinement was identified as dynamic recrystallization (DRX), including both continuous DRX and discontinuous DRX. Additionally, the processes of fretting wear and DRX were discussed.

Effect of Ti, Mn and Mo on the microstructure and properties of CoCrFeNi high entropy alloy coatings prepared by laser cladding

CoCrFeNi-based High Entropy Alloys (HEAs) coatings, with additions of Ti, Mn, and Mo, were synthesized using laser cladding (LC). The pure CoCrFeNi HEA had a uniform FCC structure, exhibiting the lowest hardness and wear resistance but good corrosion resistance. The Ti-added HEA had an FCC+Laves+η phase structure, showing increased hardness and wear resistance due to abrasive and mild surface fatigue wear, though with the poorest corrosion resistance. The Mn-added HEA maintained a single FCC structure with coarser grain boundaries, exhibiting lower hardness and reduced wear resistance due to adhesive, abrasive wear, and minor surface fatigue wear, but with the best corrosion resistance.The Mo-added HEA developed a eutectic structure of FCC and σ phases, achieving the highest hardness and wear resistance due to oxidative wear, but showed moderately decreased corrosion resistance. The varying microstructures significantly impacted the coatings' mechanical properties and corrosion behavior, highlighting the critical role of alloying elements in customizing LCed-HEA coatings for specific applications.

Cutting performance and wear mechanism of submicron and ultrafine Ti(C, N)-based cermets

The complex thermal-mechanical coupling among Ti(C, N)-based cermet tool, workpiece and chip affects immensely the tool life, machining quality and costs during high-speed cutting, which makes the investigation on wear mechanisms of tools quite important. In this work, submicron and ultrafine Ti(C, N)-based cermet tools were prepared by vacuum sintering technology, and the cutting performance of the tools was evaluated by continuous dry cutting. The aim of this work is to unravel the wear mechanisms of submicron and ultrafine Ti(C, N)-based cermet tools based on the cutting performance and wear characteristics of both the cutting tools and chips generated during high-speed cutting. The Vickers hardness, flexural strength and tool lifespan of ultrafine Ti(C, N)-based cermets are significantly superior to those of submicron Ti(C, N)-based cermets because of grain refinement strengthening and the improved distribution of metal phases. Tool wear depends to a large extent upon the contact states and heat transfer ability at different locations of the tool edge, which are characterized by simultaneous action and mutual transition from abrasive, adhesion, surface fatigue and oxidative wear. Overall, ultrafine Ti(C, N)-based cermet tools with excellent comprehensive properties exhibit a distinctly reduced tool wear at different wear regions.

The tribocorrosion behavior of the (AlCoCrFeNi)x/(WC–10Co)1-x composite coatings produced via high velocity oxy-fuel thermal spraying

The (AlCoCrFeNi)x/(WC–10Co)1-x, (x = 100 wt%(HW1), 75 wt%(HW2), 50 wt% (HW3)) composite coatings are fabricated on 3Cr13 martensite stainless steel using high velocity oxy-fuel (HVOF) spraying technology, and the tribocorrosion experiment is carried out in artificial seawater. The tribocorrosion mechanism of the coatings and counterbody are analyzed. Particularly, the synergistic effect of corrosion and wear is explored using the ASTMG119. The introduction of WC-10Co improve the microhardness of the composite coatings, but decrease their corrosion resistance, which are due to the galvanic corrosion of the WC-10Co and HEA. Notably, the results of synergistic effect show that the corrosion of the HW1 coating has an inhibitory effect on wear. The volume loss of tribocorrosion increase with the introduction of WC-10Co, with the HW3 coating experiencing a volume loss of only 46 % compared to that of 3Cr13. The HW1 coating mainly suffers from abrasive wear, surface fatigue wear and adhesive wear. The main wear mechanism of the HW2 and HW3 coatings are abrasive wear, while the fatigue wear is enhanced with the participation of WC-10Co. And the counterbody of the three coatings mainly suffers abrasive wear.

Experimental investigations to assess surface fatigue failure in rolling contact bearing

Rolling element bearings are the most important components in almost all rotating machines. These bearings are often subjected to repetitive load cycles at different operating conditions. Excessive loads, speeds, and improper operating conditions lead to the propagation of defects on their load-bearing surfaces, thereby causing a negative impact on the performance of rotating machines. This paper presents the results of experimental investigations to assess wear propagation in roller bearings using lubricant degradation, vibration, and statistical parameter analysis methods. A roller bearing setup was developed in the laboratory, and the test bearing (NJ 307E) was subjected to fatigue tests over a period of 900 h. The bearing was operated at a speed and radial load of 800 rpm and 1 kN, respectively. The film thickness analysis revealed a transition in lubrication regimes during 600–900 h of operation. Grease structure degradation and oxidation analyses were carried out using scanning electron microscope images and the Fourier transform infrared radiation technique. Further, the vibration signals are extracted from the bearing housing at regular intervals. Using the fast Fourier transform technique, these vibration signals were used to analyze bearing fault frequencies to highlight the faults developed on bearing contact surfaces. The statistical features of vibration signals such as root mean square, kurtosis, and crest factor were used to assess the severity of wear propagated on the bearing contact surfaces. Integrating tribological and vibration parameter analysis techniques provided a reliable assessment of surface fatigue wear propagated on the roller-bearing contact surfaces.

Cr3C2 reinforced tin-bronze matrix composites with enhanced mechanical properties and wear resistance

The tin bronze-xCr3C2-graphite composites (x = 5, 10, 15, and 20 wt%) were fabricated by mechanical alloying and spark plasma sintering. Fine-scale uniform distribution of composites was achieved. The Cr3C2 particles enhanced the mechanical properties and wear resistance of copper-based composites. The as-sintered tin bronze-20Cr3C2-graphite showed a hardness of 109 HV, a compressive strength of 333 MPa, and a yield strength of 219 MPa. In addition, the wear rate of as-sintered tin bronze-20Cr3C2-graphite was maintained in the order of 10−5 at 30 N, 50 N, and 70 N. The wear mechanism of the studied composites varied from surface fatigue and adhesion wear to abrasive wear with the increase of Cr3C2 content during dry sliding. These findings provide a new method for developing copper-based composites with enhanced mechanical properties and wear resistance.

A study of surface fatigue wear and influence of contaminated lubricant in journal bearing system using tribological and vibration analyses

In the present work, journal bearing performance was evaluated using condition monitoring processes namely wear debris, vibration signal, lubricant oil degradation and temperature analyses. The journal bearing system was operated at 800 rpm and 200 N constant speed and load over a period of 1200 h. The lubricant oil samples were collected for every 300 h of test duration for oil degradation and wear particle analyses by using Fourier transform infrared radiation (FTIR) and scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDS) techniques, respectively. FTIR results provided specific chemical bonds and functional groups contained in the degraded oil. The vibration signals were acquired for every 100 h of operation, and a fast Fourier transform (FFT) frequency spectrum technique was employed for vibration signal analysis. The friction coefficient and specific wear rate parameters were considered to evaluate the tribological performance of the journal-bearing system. Statistical parameters, namely root-mean-square and kurtosis, were evaluated. Wear mechanisms such as abrasive, adhesive and surface fatigue wear were observed on the journal-bearing contact surfaces using a USB optical microscope. The scoring on the bearing element confirmed the fault development and resulted in an increase in vibration amplitudes. Higher mass loss in the bearing material was observed due to high friction and wear rates owing to its being a softer material than that of the journal material. The results obtained from the aforementioned parameter assessment techniques provided a reliable information on the defects which appeared on journal-bearing contact surfaces.

Electrochemical study on the fretting corrosion synergistic damage mechanism of 316L SS in different dissolved oxygen solution

Nowadays, material aging issues in the nuclear industry have received wide attention as they need costly maintenance strategies to deal with. Therefore, it is important to study the degradation mechanism of materials to improve their service life. In this study, in-situ electrochemical measurement techniques were used to investigate the fretting corrosion synergistic damage mechanism of 316L SS tube against zirconia ceramics plate in the solution with different dissolved oxygen (DO) concentrations. The results show that a more uniform passive film with the main composition of corundum oxides γ-Fe2O3 and oxyhydroxide γ-FeOOH formed on the wear scar under higher DO concentration, which hindered the charge transfer and improved corrosion resistance. The passive film modifies contact pressure and changes wear behavior, resulting in a 55.5 % reduction in the fretting corrosion damage. The main damage mechanism changes from abrasive wear to a mixing mechanism of surface fatigue and abrasive wear. The contribution of the synergistic damage effect was quantified, which is the key part of fretting corrosion damage and weakens with the increase of DO concentration. According to the experimental results, a prediction model of corrosion-induced wear damage was proposed based on the Archard equation, Hertz contact theory, and passive film coverage model.

Microstructural, mechanical and high-temperature tribological performance of Fe-based fully amorphous and amorphous/crystalline coatings

In this research, fully amorphous and amorphous/crystalline (A/C) Fe-based coatings were explored for high-temperature tribological applications. The commercially available gas atomized feedstocks were sprayed using high velocity oxygen fuel (HVOF) processes. The microstructural, mechanical and tribological behaviour of the coatings were investigated and compared. The fully amorphous Fe-based amorphous coating exhibited higher wear resistance at 600 °C than room temperature (RT) with high thermal stability and performed superior to A/C coatings at both temperature conditions. Detailed analysis of worn surfaces demonstrated that fully amorphous coatings were dominated by abrasive wear and oxidative wear at RT and oxidative and adhesive wear at 600 °C, whereas A/C coating suffered abrasive, surface fatigue wear and minor oxidation at both RT and 600 °C. A thick oxide glaze layer formed onto the worn surface of fully amorphous coatings, which enhanced the high-temperature mechanical properties and prevented severe wear loss. The Fe-based amorphous coating exhibited superior wear resistance and retained its phase structure, which established it as a potential high-temperature protective coating for tribological applications.

Assessing the fatigue wear effect on traction coefficient and dynamic performance of roller bearing

Rolling element bearings are commonly employed in rotating machinery to support rotating shafts. These machinery elements are vulnerable to failure due to increased friction and heat, which cause progressive wear on the rolling interaction surfaces of the bearing. The failure of bearings causes an unpredicted shutdown of equipment, leading to an increase in downtime and financial losses. Various condition monitoring techniques have been developed for periodic assessment of failure in roller-bearing systems. The focus of this work is to establish a relationship between surface fatigue wear, film thickness [Formula: see text], asperity load ratio [Formula: see text], lubricant film stiffness [Formula: see text] and traction coefficient [Formula: see text] parameters. A periodic assessment of the above-mentioned parameters was made on the test bearing, which was subjected to a fatigue test for 2000 h. The results acquired from the experimental study highlighted that, as surface fatigue wear on the bearing interaction surfaces and lubricant degradation occurred with an increase in fatigue load cycles, the asperity load ratio [Formula: see text] and traction coefficient [Formula: see text] parameters showed a gradual rise in trend which further resulted in a difference in the dynamic behaviour of the bearing system.

Experimental Investigations to Study the Effectiveness of Cepstral Features to Detect Surface Fatigue Wear Development in a FZG Spur Geared System Subjected to Accelerated Tests

Gears are essential machine elements used to transmit power and motion from one unit to another under desired angular velocity ratio. Various types of gears have been developed to fulfill power transmission requirements in industrial applications. Under normal or fluctuating operating conditions, increase in fatigue load cycles, transition in lubrication regimes, fluctuating loads and speeds, etc., result in various surface fatigue wear modes which affect the performance of geared system. The severity of wear anomalies developed on gear tooth surfaces can be assessed by using vibration signals acquired from the gear box. On the other hand, reliable wear assessment is very important to perform maintenance action which depends on the sensors, data acquisition procedure, vibration signal analysis and interpretation. This paper presents results of the experimental investigations carried out to assess initiation and propagation of surface fatigue failure wear modes developed on gear tooth contact surfaces. A FZG back to back power recirculation type spur gearbox was used to conduct fatigue test experiments on spur gears under accelerated test conditions. Accelerated test conditions resulted in a rapid transition of lubrication regimes, i.e., hydrodynamic lubrication regime to boundary lubrication regime which triggered surface fatigue faults on gear tooth surfaces. A cepstral analysis method was used to assess fault severity in the geared system. The results obtained from the cepstral features were correlated to various surface fatigue faults and reduction in gear tooth stiffness. Results obtained from the experimental investigations highlighted the suitability of cepstral features to assess incipient faults developed on spur gear tooth surfaces.

Comparison of the tribological behavior of quench-tempered ductile iron and austempered ductile iron with similar hardness

The tribological behavior of quench-tempered ductile iron (QTDI) and austempered ductile iron (ADI) with similar hardness was investigated. QTDI was composed of cementite particles, ferrite and spheroidal graphite, whilst ADI was consisted of acicular ferrite, retained austenite and spheroidal graphite. A higher yield strength was obtained for QTDI compared with ADI. Wear tests indicated that QTDI exhibited a lower friction coefficient than ADI. However, ADI had a better wear resistance than QTDI, which was because the transformation of residual austenite into martensite induced by friction stress resulted in the increase of surface hardness. Worn surface morphology indicated that the main wear mechanisms of QTDI was adhesive and abrasive wear. However, the surface fatigue wear was observed for ADI.

Effect of laser heat treatment on AlxTi1-xN-based PVD coatings, deposited on carbon and tool steel substrates

This paper highlights the effect of laser heat treatment on the adhesion and sliding wear of physical vapour deposited (PVD) multilayer AlxTi1-xN and nanocomposite AlxTi1-xN/α-Si3N4 coatings on carbon (C45E, preliminarily bulk hardened) and tool steel (Vanadis® 6, preliminarily bulk hardened and tempered), as well as substrate steel microstructure and hardness. The hardened zone in carbon steel generally comprises martensite and retained austenite. The hardened zone in tool steel contains martensite and retained austenite, as well as M7C3 (M = Fe, Cr) and MC (M = Fe, V) carbides. Laser heat treatment increased the average surface hardness of the carbon steel by 1.5–3.1 times and that of the tool steel by 1.1–1.2 times. The critical adhesion loads Lc1 and Lc2 enlarged by 1.22.6 times and by 1.2–1.3 times, respectively, in the case of the coatings deposited on the carbon steel. However, only slightly positive or no changes in the critical adhesion loads were observed for the tool steel case. The scratch crack propagation resistance (CPRs) of the coatings increased by 1.1–4.8 times, being more pronounced for the carbon steel substrate. The improvement of adhesion was assumed to be the result of the increased hardness (H) to Young's modulus (E) H/E and H3/E2 ratios of the substrate steel. Wear resistance of the coatings improved by 1.3–1.7 times. Scuffing and surface fatigue wear were the principle wear mechanisms in all the cases. However, the first mechanism was more remarkable for laser heat treated samples, and the second for the samples that remained untreated by laser. Apart from the above-mentioned increment of H/E and H3/E2 ratios, the improvement of wear resistance was explained by the increased CPRs values of the coatings and by the presumed precipitation of the AlN phase within them.

Nano- and micro-mechanical properties and corrosion performance of a HVOF sprayed AlCoCrFeNi high-entropy alloy coating

In this work, a gas atomized feedstock was used to fabricate an AlCoCrFeNi HEA coating using the high-velocity oxygen fuel (HVOF) process. The coating’s resistance to room temperature surface degradation was evaluated using dry sliding wear and seawater corrosion testing. The coating retained the feedstock phase structure with negligible in-flight oxidation and was composed of a majority BCC phase with a minor B2 phase, resulting in a high micro- and nano-hardness of ~7 GPa. These observed phase compositions were consistent with thermodynamically calculated phase predictions using a CALPHAD model. Microstructure-mechanical property mapping revealed uniform microstructural characteristics. However, the multiscale wear resistance of the coating was critically affected by the presence of the hard BCC/B2 phase composition, which led to severe brittleness. Combinatorial assessment of the worn surface, wear debris and counter body indicated that wear was dictated by a combination of abrasive, surface fatigue, tribo-oxidation and adhesive wear. In addition, the coating exhibited superior general corrosion resistance compared with conventional SS316L, but the selective dissolution of the B2 phase preceded poor localized corrosion resistance, ultimately leading to pitting corrosion. • HEA AlCoCrFeNi coating with BCC/B2 phase composition consistent with CALPHAD phase predictions. • Microstructural homogeneity achieved at both nano- and micro-level. • Brittleness imparted by BCC/B2 observed during nano-scratch testing at high loads. • Dry sliding wear was dominated by abrasive wear, resulting in high volume wear rate. • General corrosion resistance superior than SS316L, however, lacks pitting resistance.

Effect of phase composition on microstructure and wear resistance of (Al16.80Co20.74Cr20.49Fe21.28Ni20.70)99.5Ti0.5 high-entropy alloy coatings

The (Al16.80Co20.74Cr20.49Fe21.28Ni20.70)99.5Ti0.5 high-entropy alloy coating was successfully prepared by laser cladding. The microstructure of the coating was controlled by changing the laser scanning speed, and three kinds of high-entropy alloy coatings with different microstructures were obtained. All coatings had an equiaxed grain structure, but the content of the BCC phase gradually increased with increasing laser scanning speed. In addition, the micro-mechanical properties of each phase in the coating and the creep characteristics of the coating were explored by the nanoindentation method. It was found that the BCC phase had greater hardness and elastic modulus than the FCC phase, so the content of the BCC phase dominated the hardness and wear resistance of the coating. At the same time, as the laser scanning speed increased, the creep resistance of the coating was gradually enhanced. When the laser scanning speed was 17 mm/s, the coating had the best wear resistance at room temperature and 500 ℃ high temperature. The main wear forms of the coating were abrasive wear, surface fatigue wear, and oxidative wear.

Effect of cBN content and additives on sliding and surface fatigue wear of spark plasma sintered Al2O3-cBN composites

Cutting tools containing superhard phases enable efficient dry machining resulting in reduced human and environmental risks. In the current work, spark plasma sintered composites containing up to 20 vol% cBN in Al2O3-based matrix with an addition of 15 vol% ZrO2 or 10 vol% TiN have been tested under dry sliding (with multiple restarting to better simulate real working conditions) and surface fatigue (with in-situ monitoring of acceleration indicating evolution of the test area) conditions. Dry sliding was carried under two configurations of “ball above sample” and “ball below sample” to study the effect of wear debris entrapment in a wear scar. The importance of a longer test duration (40 000 s, i.e. more than 10 h) during sliding of extensively polished ceramic materials with “mild” wear regime is emphasized. The reason for long running-in process with characteristic threshold is explained. The worn surfaces were studied using scanning electron microscopy, energy dispersive spectroscopy and 3D profilometry to understand the responsible wear mechanisms. The wear rates are reported in comparison to pure Al2O3 ceramic. The surface fatigue test was able to identify the material (Al2O3-20cBN-15ZrO2) that according to previous research by authors exhibits lowest wear in dry cutting conditions.

The influence of nano-CeO2 on tribological properties and microstructure evolution of Cr3C2-NiCrCoMo composite coatings at high temperature

With the aim of further improving the high-temperature tribological properties and extending the application of typical chromium carbide cermet coating, a novel Cr3C2-NiCrCoMo/nano-CeO2 (NCE) composite coating deposited by high-velocity oxygen fuel spray (HVOF) was developed based on the collaborative modification of the multielement alloy adhesive phase. The influence of nano-CeO2 content on high-temperature tribological properties and microstructure evolution of the coating during high-temperature friction was studied. Tribological properties, microstructure and phase composition of the coating after friction at 400 °C, 600 °C and 800 °C were carefully investigated. The results indicate that the novel NCE coating exhibits improved wear resistance at high temperature with lower friction coefficient and wear depth due to the lubrication of oxides and improvement of oxide film adhesion. The wear mechanism of the NCE coating mainly consists of abrasive wear and surface fatigue wear. With the increase of friction temperature, the oxide film replaces the coating surface as the main object of wear. The addition of nano-CeO2 decreases the threshold temperature of Ostwald ripening triggered by the secondary precipitated nano-Cr3C2 phase and promotes the growth and aggregation of the nano-Cr3C2 precipitated from the adhesive phase of the NCE coating, which contributes to wear resistance of the coating in the subsequent friction.

Experimental study on the surface microstructural evolution and fatigue wear resistance of pearlite wheel steels during rolling-sliding condition

In present paper, the relationship between fatigue and wear of three kinds of pearlite wheel steel samples is investigated by using rolling wear tester under 0.2% slip ratio condition. The results show that the weight loss, the surface hardness and the thickness of plastic deformation layer of three kinds of wheel samples are increased as the increase of cycles during rolling wear process. The weight loss of the G1 wheel sample is the highest owing to the existence of a large amount of proeutectoid ferrite (PF)grains. The correlation between weight loss and fatigue is competitive. High weight loss of the G1 wheel sample can hinder the formation of fatigue wear cracks. As a result, the G1 wheel sample surface changes to smooth after wear. The low weight loss of the G2 wheel sample and the G3 wheel sample cannot hinder the production of fatigue wear cracks during wear process. At the late wear stage, the wheel sample surface produces many fatigue wear cracks, and the wear mechanism becomes fatigue wear. Fatigue wear cracks, which are the rolling contact fatigue (RCF) crack source, can accelerate the RCF failure of wheel samples.

Fatigue Damage of an Asperity in Frictionless Normal Contact with a Rigid Flat

Surface fatigue wear widely exists, and it occurs as long as a sufficient number of loading–unloading cycles are applied. Slowing down surface fatigue wear requires understanding the evolution of fatigue damage in the surface. Real surfaces are composed of many asperities; therefore, it is important to study the fatigue damage of a single asperity. A finite element model of an asperity subjected to cyclic elastic–plastic normal loading was developed under frictionless contact condition. The asperity can be either completely or partially unloaded in a loading cycle. For the sake of completeness, both cases were investigated in the present study. The multiaxial Fatemi-Socie fatigue criterion was adopted to evaluate the fatigue damage of the asperity in elastic shakedown state, which was achieved after several loading cycles. For the case of complete unloading, severe fatigue damage was confined in a subsurface ridge starting from the edge of the maximum loaded contact area. The shape and volume of the wear particles were predicted based on a fundamentally valid assumption. For the case of partial unloading, the fatigue damage was much milder. Finally, potential research directions to expand the current study are suggested.

Wear performance of layered (TiNb)C reinforcement in surface of TiNb alloy

Deficiency in the wear resistance of TiNb alloy makes it necessary to enhance the surface properties of the alloy. Herein, in-situ solid-state carburization reaction (ISSCR) was used to produce (TiNb)C surface-reinforced layer (SRL), which can provide high surface wear resistance. The relationships between microstructure, hardness, elastic modulus, and tribology properties were investigated. The SRL has layered structure, in which the outer layer has higher hardness and lower elastic modulus than that of inner layer, the average hardness of SRL is about 31.74 GPa that is 7.38 times as that of the TiNb substrate. The ball on disc unlubricated sliding wear tests indicate that the wear rates of the SRLs range from 2.1 × 10−7 to 3.3 × 10−7 g/m, but the wear rate of the substrate is about 516.3 × 10−7 g/m. With the change of load and sliding time, the outer layer of SRL present delamination under load of 10 N and spalling pits under load of 20 N, both of which are indications of surface fatigue wear; further, the inner layer of SRL present micro-cutting wear caused by of two-body abrasion under load of 20 N. The outstanding wear resistance of SRL will significantly protect the integrality of TiNb substrate.