Change In Wear Mechanism Research Articles

Effect of heat treatment temperature on mechanical and tribological properties of copper impregnated carbon/carbon composite

To obtain pantograph strip with high toughness and good friction behaviors, copper impregnated carbon/carbon (C/C) composite was fabricated using chemical vapor deposition, heat treatment and impregnating technologies, and microstructure, mechanical and tribological performances were investigated. As the heat treatment temperature increases, flexural strength has a decreasing tendency, and the failure mode changes from brittle fracture to pseudo-plastic fracture. Carbon crystal degree of copper impregnated C/C composite is increased by the (Above 2000 °C) heat treatment, which helps wear surface form a smooth tribolayer, prompting the decreases of standard deviation of friction coefficient and arc discharging frequency, and the main wear mechanism changes from arc erosion to abrasive wear during the current carrying friction tests.

Transitions of Wear Characteristics for Rubber/Steel Seal Pairs During the Abrasive Wear Process

Abrasive wear resulting from the microclastic rock is a common failure phenomenon in the drilling environment that often limits the sealing ability and the service life of seals. In this study, the friction and wear process of fluoro rubber (FKM) seals against 304 stainless steel (SS304) after one single entry of SiO2 abrasives were investigated. The influence of the changes in particle state on friction coefficient evolution, wear loss evolution, wear morphologies, and wear mechanisms were discussed in detail. The results indicate that the presence of abrasive particles dispersed between the sealing interfaces clearly improves the friction performance of the seal pairs and deteriorates the wear performance of the metal counterpart. The movement and breakage of particles after one single entering into the sealing interface were obtained. And on this basis, the stable wear process can be divided into three stages. In addition, the main causes contributed to this change of wear mechanisms are the random movement and process of continuous breakdown of abrasive particles. Furthermore, the transition of the wear mechanism that clearly describes the wearing behavior of the seal pairs under these abrasive wear conditions was identified. The results of this study enhanced our understanding of the abrasive wear degradation of rubber seal in practical drilling applications.

Chevrel phase-based solid lubrication coating for wear resistant electrocontact friction pairs in vacuum

The work comparatively studies the wear kinetics of copper friction pairs with Chevrel phase-based coating (Cu-Mo-S) and without it in vacuum of 1.5x10−3 Pa. The coating is deposited on test pads by the ion-plasma method. The tribological investigations scheme were used the “disk – coated pad”. The detected falling of the wear rate of the friction pair with the coating is explained by the change of the adhesive wear mechanism to fatigue one.

Effect of Tempering on Tribological Properties of 13Cr Martensitic Stainless Steel and Alumina Material Pair in Dry Sliding

This present study seeks to understand tribological properties of 13Cr martensitic stainless steel (MSS) in austenitizing and tempering conditions (300, 550, and 700 °C). A ball-on-plate configuration with an alumina ball as the counterface was employed for dry sliding experiments. Complementary analytical techniques such as 3D optical profilometry, optical microscopy, scanning electron microscopy/energy-dispersive spectroscopy, and microhardness measurements were used to elucidate the operating wear mechanism. The results showed that the coefficient of friction (COF), wear rate, and wear mechanism changed significantly with tempering temperature. Austenitized and 300 °C tempering condition exhibited stable COF variations with time, whereas fluctuating and increasing COFs with time were observed in 550 and 700 °C tempering conditions, respectively. Wear resistance for the tempering condition was lower than that for the austenitizing condition, with the least wear resistance for the 550 °C tempering condition. The wear resistance of the alumina ball also followed the same trend as for 13Cr MSS. The least wear resistance of the counterface material was observed against the 550 °C tempering condition. These observations were attributed to the (a) formation of large amount of nanosized carbides and (b) embedment of the counterface material during sliding. The austenitizing and 300 °C tempering conditions showed abrasive plus mild oxidation wear mechanism, whereas tempering at 550 and 700 °C showed delamination plus the presence of adhesion traces and a compacted tribolayer plus severe oxidational wear mechanism, respectively. The present results clearly highlight the changes in wear mechanism of 13Cr MSS against the counterface alumina ball with the developed microstructural changes during tempering treatments.

A Comparison of the Abrasive Wear Behaviors of Cast Iron and Cast Steel Materials

The two body abrasive wear of cast iron and cast steel was studied by scratching tests. The tests were carried out by installing a scratching apparatus on the spindle of a CNC machine tool. Cemented carbide inserts were used as tools to scratch the test samples. The abrasive wear behaviors of cast iron and cast steel were investigated by comparing their scratch morphologies and the subsurface microstructures. For cast iron, the crushing of the graphite ribbon and inconsistent deformation at the boundaries of pearlite and graphite are important reasons for the exfoliation of the surface hardening layer and the initiation of surface cracks. The cast steel can undergo sufficient plastic deformation; only when the scratch depth and scratch speed increase to a certain value do cracks occur on the side pile-ups of the groove. Both microploughing and microcutting wear mechanisms exist at the same time, but the dominant wear mechanism changes between the two under different scratch conditions. The pile-up ratio can be used to measure the strength of the microcutting and microploughing actions of cast steel; this parameter increases with increasing scratch depth and decreases with increasing scratch speed and extrusion front rake angle.

An Effect of Fillers on the Structure and Abrasive Wear of Polyurethane Urea

The introduction of small amounts of calcium stearate and molybdenum disulfide into polyurethane ureas based on a oligoether of polyoxytetramethylenediol with a molecular weight M~1000 does not lead to a significant change in the abrasive wear mechanism of the polymer material. The concentration dependence of the wear degree on the filler content has an extreme character, which is associated with the different direction of the filler effect on the cohesive and frictional properties of the studied material.

Effect of laser shock peening and carbonitriding on tribological properties of 20Cr2Mn2Mo steel alloy under dry sliding conditions

In this study, the effect of laser shock peening and low-temperature vacuum carbonitriding on the tribological properties of 20Cr2Mn2Mo steel alloy was investigated. The original sample and samples treated by laser shock peening with different laser energy and number of impacts were carbonitrided in vacuum at 760 °C. The effect of laser shock peening parameters on surface roughness, microhardness, coefficient of friction, and wear properties was studied. The results indicated that the surface roughness and microhardness increase with respect to laser energy and number of impacts. For exceedingly high laser energy or number of impacts, the coefficient of friction evidently increases. Furthermore, laser shock peening and carbonitriding lead to high-density dislocations and second-phase particles. With increasing laser energy and number of impacts, the primary wear mechanism changes from abrasive wear to a mix of abrasive and adhesive wear.

Influence of Al2O3 particles on the tribological properties of CoCrAlYTa coating produced by laser-induction hybrid cladding

The influence of Al2O3 addition on the microstructure, mechanical and tribological properties of CoCrAlYTa coating produced by laser-induction hybrid cladding was systematically investigated. The results show that the coatings exhibit high metallurgy quality with no obvious defects, and mainly consist of γ, β and TaC phases. In the cladding process, a part of O element exists in the TaC and increases with the increased Al2O3 content, while the other exists in the form of Y2O3 due to low Gibbs free energy. As the Al2O3 content increases, the volume fraction of β phase (Vβ) changes from 23.82 vol% to 67.72 vol%, and leading to the microhardness of coating increased from 515.15 HV to 610.17 HV. Meanwhile, the wear rate of coating increases with the Vβ in a relationship of y = −5.97x+110.65, due to a fact that the wear mechanism changes from adhesive wear to microcutting.

Experimental and modelling study of the effect of martensite volume fraction on friction and wear of dual-phase steel at microscopic scale

In this work, the influence of martensite volume fraction, load and attack angle on hardness, friction and wear of ferrite and martensite phases of a dual-phase microstructure is investigated through nanoindentation and scratch tests with conical tips. Friction coefficient increases with the attack angle and is always higher for ferrite than for martensite. For martensite phase, friction coefficient increases and wear resistance decreases as martensite volume fraction increases. As the attack angle increases, wear mechanism changes from ploughing to cutting for martensite. Experimental results correlate to the Axén & al. approach based on the Equal Pressure model.

Synergetic effects of water and SO2 treatments on mechanical and mechanochemical properties of soda lime silicate glass

The synergetic effects of water and SO2 treatments on mechanical and mechanochemical wear properties of SLS glass were studied in this study. The results show that the nanomechanical properties (nanohardness and reduced modulus) as well as Vickers hardness and fracture toughness of treated SLS glass surface are increased, regardless of various treatment environments. After treated in dry SO2, the mechanochemical wear resistance of SLS glass in 40% RH becomes higher than pristine glass, but it doesnot change significantly in 70% RH. In contrast, after treated in wet SO2, the wear resistance of SLS glass in 40% RH decreases remarkably, and it shows much less wear resistance in 70% RH. This must be due to the change of glass surface structure and wear mechanism during the wear process. These results can provide deeper understanding of wear mechanism of glass and be helpful for operation process of functional and engineering glasses.

Microstructure and tribological behavior of in situ ZrB2/A356 composites prepared under magnetic field

A356-3 wt% ZrB2 composite was prepared by in-situ magnetochemical reaction at x Hz(x = 0, 5, 10, 15) magnetic field frequency, and its dry sliding friction and wear properties were studied. XRD results show that the composite is composed of ZrB2 and aluminum phase. SEM analysis showed that the size and distribution of ZrB2 particles improved with the increase of frequency. The size of ZrB2 particles in the cluster is about 20–100 nm. The hardness test results showed that with the increase of frequency, the hardness of the composite increased to 235.72 Hv. The friction and wear test results show that the friction coefficient and wear rate of the composite material under 10 N load are lower than that under 5 N load, and the lowest values are 0.28112 and 0.50875, respectively. With the increase of frequency, the wear mechanism changes from adhesive wear to abrasive wear. The effect of magnetic field on in-situ reaction is discussed.

Friction and wear behaviors of bare and diamond-like carbon/chromium bi-layer coated SKH51 steel at low temperatures

The durability and reliability of mechanical systems operating under low-temperature conditions are subject to degradation caused by abrupt changes in the tribological characteristics of contact pairs. In this regard, the friction and wear behaviors of bare and diamond-like carbon (DLC)/Chromium (DLC/Cr bi-layer) coated SKH51 steel at low temperatures were assessed comprehensively. The bi-layer coating was deposited onto the SKH51 substrate using a combination of pulsed DC and radio frequency magnetron sputtering . Tribological tests were conducted using a custom-built reciprocating tribo-tester installed inside a cooling unit with temperature-control capabilities. The nano-structural properties of the coating and governing wear mechanisms were investigated using high-resolution transmission electron microscopy (HR-TEM), laser confocal microscopy , scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and ultra-nano indentation. The results revealed a significant increase in the wear rate of SKH51 due to changes in wear mechanism and the degradation of mechanical properties as the temperature decreased. The DLC/Cr bi-layer coating significantly reduced the wear of SKH51, particularly at low temperatures. The formation of a thin layer of frozen water at subzero temperatures played a major role in determining the wear behaviors of the specimens. • Reducing the temperature changed the wear mechanism of SKH51 steel. • Reducing the temperature increased the wear rate of SKH51 steel by 200%. • The wear rate of the DLC/Cr bi-layer coating was the lowest at 0 °C. • DLC/Cr bi-layer coating can effectively protect SKH51 steel at subzero temperatures.

Thermal oxidation and its effect on the wear of Mg alloy AZ31B

Magnesium alloy AZ31B is an important lightweight, high specific strength material for new generations of energy-effective vehicles. Presently, a critical challenge that the vehicle production is facing is how to prevent the material from surface oxidation at elevated temperatures. This paper aims to investigate the effect of thermal oxidation and chemical compositions of oxides on the wear of AZ31B. The tribology experiments were conducted by a contact pair of pin-on-disc under elevated temperatures. The disc and pin were made by AZ31B and the production tooling steel 86CrMoV7, respectively. The composition and morphology of the disc surface were examined by the scanning electron microscope (SEM). It was found that the initial surface oxide film naturally formed prior to testing at room temperature (RT) was thin, compact and protective. However, the film would lose its protection capability when the temperature rose because of the thickened film layer and the emergence of the oxide nodules. At a higher temperature, the oxide nodules grew more quickly. Besides, more oxide nodules emerged, and the film started to crack as the temperature increased, leading to a higher wear rate. The friction coefficient varied at different temperatures due to the change in the dominant wear mechanism of AZ31B. The minimum wear rate was found to occur at 200 °C and the maximum at 400 °C. It was also found that the surface hardness of AZ31B decreased from 75 HV2 at 25 °C to 50 HV2 at 200 °C, and then fluctuated around 50 HV2 at higher temperatures, which further accelerated the wear process.

WEAR PROPERTIES OF ALUMINUM MATRIX COMPOSITES REINFORCED BY GRAPHENE ENCAPSULATED SiC NANOPARTICLES

Graphene encapsulated SiC nanoparticles reinforced aluminum matrix composites were prepared by high energy ball-milling and hot-press sintering methods. The effect of graphene content on microstructure and wear properties of composites was investigated. The results show that the graphene sheets successfully encapsulates SiC nanoparticles to form a composite reinforcement phase under the condition of the graphene content of 1 wt.%. SiC nanoparticles encapsulated with graphene predominantly are homogeneously distributed on the grain boundaries of Al matrix. The interface between graphene and Al matrix is sharpand no Al-C compound is formed on the interface. The increase of the reinforcement phase reduces the wear performance of the composite material. The main wear mechanisms of aluminum-based composite materials are the combination of delamination wear and abrasive wear. As the graphene content increases, the wear mechanism changes from abrasive wear to delamination wear.

Influence of Friction Stir Processing on Wear, Corrosion, and Fracture Toughness Behavior of 2507 Super Duplex Stainless Steel

Super duplex stainless steels (SDSS) are used in offshore applications and oil/gas plants operating under severe service conditions due to their superior mechanical and electrochemical properties. Fracture toughness, wear and corrosion resistance of a material depends largely on its microstructure and can be improved by refining the latter. Friction stir processing (FSP) can be employed to refine the microstructure of the material, resulting in superior fracture toughness, wear, and corrosion resistance. In the present research, SAF 2507 SDSS was subjected to FSP with optimized processing parameters to study the influence of FSP on fracture toughness, wear, and corrosion resistance of the material. It was observed that FSP refined alloy grains by decreasing the grain size from an average of 160 µm in the base metal to 2-30 µm in the stir zone. Refinement of grains increased the hardness of the material, which enhanced its wear resistance by more than 15%. Wear track and debris analysis revealed the change in wear mechanism of the processed material. FSP also modified the surface composition of processed material, which served to improve its corrosion resistance by more than 80%. Morphology of the corroded surfaces of base and processed material showed that the processed material was more resistant to corrosive attacks than base material. FSP enhanced the grain boundaries in the processed region which improved the fracture toughness after exposure to accelerated corrosion by about 26%. Fractographic study revealed that processed material had brittle fracture behavior while base material had ductile fracture behavior.

Effect of Aging Temperature on the Microstructure, Local Mechanical Properties, and Wear Behavior of a UNS S32750 Super Duplex Stainless Steel

In this paper, the effect of aging temperature on the microstructure, local mechanical properties and wear behavior of a UNS S32750 super duplex stainless steel is investigated. A massive preferential precipitation of σ phase and Cr2N is detected at the periphery of ferrite with an increase in their extent as aging temperature increases. Simultaneously, the δ phase decomposition is accentuated with temperature and reaches its maximum at 850 °C. This behavior results in an enhancement in hardness and Young’s modulus accompanied by a higher plasticity ratio. The wear resistance of the aged samples is investigated in terms of friction coefficients and wear rates against two counterparts. The wear performance follows σ phase presence, the higher σ phase extent, the higher the wear resistance. It is found that the change in wear mechanisms in the 850 °C aged samples from abrasive against AISI-304L counterpart to adhesive-oxidative against Al2O3 counterpart is responsible in the increase in wear resistance.

Study on Wear Properties of J11 Wheel Steel with Nonuniform Microstructure

In actual wheel–rail systems, a nonuniform microstructure of the wheel and rail materials is a serious problem. A double-disk rolling wear test device was used to study the influence of the nonuniform microstructure on the wear properties of wheel materials in the present study. The results show that the microstructure of the sample 1 includes proeutectoid ferrite, pearlite, and upper bainite, which is a nonuniform microstructure. By contrast, the microstructure of sample 2 contains only proeutectoid ferrite and pearlite. During wear tests, with the increasing number of test cycles, the weight loss of the sample 1 is consistently larger than that of the sample 2. A similar trend is observed with respect to deformation of the plastic layer. For the sample 1, fatigue cracks mainly propagate along the interface between the upper bainite and pearlite, leading to rapid wear failure; the main wear mechanism changes from spalling to fatigue with the increasing number of cycles. For the sample 2, the main wear mechanism changes from adhesive wear to fatigue wear with increasing number of cycles.

Investigation on structural, mechanical and tribological properties of plasma sprayed Al2O3-40% TiO2 coating

The present work deals with tribological investigation of Al2O3-40% TiO2 coating deposited using plasma spraying. The structural characterization of coating was done using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD). The micro hardness was measured by vickers micro hardness tester whereas fracture toughness was determined by Indentation Fracture Toughness Test (IFT) method. The sliding wear tests were carried out at different test conditions involving simultaneous variation of load (P) ranging from 5 to 30 N and sliding velocity (V) ranging from 0.1 m/sec to 0.6 m/sec. The sliding wear rate increased with increasing parameter P × V and friction coefficient displayed minima at a load of 20 N and sliding velocity of 0.4 m/sec. The flash temperature showed the increasing trend with P × V parameter. The variation in coefficient of friction and wear rate with varying test conditions was associated with change in wear mechanism from plastic grooving to delamination of splats & splat fracture and formation & removal of tribo layer of Ti2O3 and Ti3O5 on worn surface.

Fretting wear behaviors of Zr-4 alloy under different ions irradiation conditions

Studying the fretting wear behaviors of Zr-4 alloy under various ions irradiation conditions plays an important role in understanding the fretting damage source of cladding in nuclear reactor. In the study, fretting wear behaviors for Zr-4 alloy under various ions irradiation conditions were summarized as function of irradiation damage level, incident ion energy and ion species. The results demonstrate that increasing incident energy produced partially or completely amorphous phase in Zr-4 alloy. The friction coefficient and wear rate increase linearly with the increase of irradiation dose, but both are saturated at high irradiation dose, which can be attributed to the existence of an adiabatic or instantaneous recombination volume around the defect. Heavy ions irradiation with large mass and radius cause more and denser defects at shallower surface than ions with smaller radius, results in lower friction coefficient but increased the wear depth and wear rate. Conclusively, the friction coefficient and wear rate of Zr-4 alloy increase at the irradiation conditions investigated in this study. The dominant wear mechanism changes from adhesive wear and abrasive wear to fatigue wear and abrasive wear.

Growth mechanism of primary Ti5Si3 phases in special brasses and their effect on wear resistance

In the present work, in-situ Ti5Si3 reinforced special brasses were prepared by melt reaction method. The synthesized Ti5Si3 phase shows various morphologies in brasses with different Ti5Si3 content, and the 3D morphological evolution of primary Ti5Si3 and its growth mechanism were investigated. The Ti5Si3 crystal, which bears D88 hexagonal crystal structure, grows along <0001> direction and is revealed by {101̅0} faces during growth. With the increase of Ti5Si3 content in the brasses, the morphology of primary Ti5Si3 significantly changes from fibers to hexagonal prisms to short-rods with hollow. In addition, the influence of Ti5Si3 volume fraction and morphology on the wear behavior of special brass was also revealed. It was substantiated that the wear resistance increases with the increasing volume fraction of Ti5Si3, and the corresponding wear mechanism changes from delamination to slight adhesive wear and abrasive wear. However, the friction coefficient shows an abnormal increase when most of the Ti5Si3 containing hollows appears in the brass. That is mainly due to the fact that the Ti5Si3 is easier to break and fall off resulted by the hollow as a crack source, which makes it unable to resist the plastic deformation of the contact surface during the sliding.