Adhesive Wear Mechanism Research Articles

Simulation study on mechanical wear of the diamond grain cutting pipeline steel

With the exploitation of marine resources, the development of maintenance operation technology for subsea pipelines transporting oil and gas has become the focus worldwide. Diamond bead wire serves as important engineering equipment in subsea pipeline maintenance, and the study of the wear mechanism of diamond grains on the beads is key to improving the cutting efficiency and lifetime of diamond bead wire. In this work, a theoretical model of the mechanical wear rate of the diamond grain was established, and a simulation model of the diamond grain cutting X65 pipeline steel was developed by applying smoothed particle hydrodynamics method. By studying the effects of the cutting factors of the diamond grain on mechanical wear, the mechanisms of adhesive wear, abrasive wear, and fatigue wear were clarified. The results indicate that the diamond grain in line contact or large surface contact with X65 steel contributes more to wear rate reduction than point contact; The mechanical wear rate predominated by adhesive wear and abrasive wear of the diamond grain increases with the increase of cutting speed and depth. And when the cutting speed is 22–26 m/s and the depth is 20–30 μm, the growing trend of the mechanical wear rate turns gentle, which is more suitable to balance improving cutting efficiency and reducing mechanical wear.

Effect of inert environment on the sliding wear behaviour of the HVOF sprayed WC-12Co coating

The reciprocating sliding wear behaviour of high velocity oxy-fuel sprayed WC-12Co coatings in the inert environment at room temperature, and 300 °C temperature with varying load conditions was investigated. The worn-out coatings and the debris were analyzed by scanning electron microscopy and Raman spectroscopy. From the wear test data, the coefficient of friction was measured as lower in the air environment at both room temperature and 300 °C, compared with the argon environment due to the development of self-lubricating tribo-oxide layers. The development of CoWO4 phases at the surface decreases friction and wear and allows the coating to uphold the tribological properties at higher temperatures. Higher loads mechanically damage the coatings and quickly remove the protective oxide layer compared with the lower loads. In the protective environment, abrasive wear and adhesive wear mechanisms were observed to be played predominant role, whereas, in the air environment, the oxidative wear mechanism was found to be significant.

Effect of Heat Treatment on the Dry Sliding Wear Behavior of the Mg-3Zn-0.4Ca Alloy for Biodegradable Implants

The wear behavior of the Mg-3wt.% Zn-0.4wt.% Ca (ZX30) alloy was tested using a pin-on-disc configuration with AZ31 alloy discs as counterparts under dry sliding conditions. The ZX30 alloy was tested in different states: as-cast, solution-treated, peak-aged, and over-aged. Wear rates and friction coefficients were measured at different loads and sliding speeds. Abrasion and oxidation were the main wear mechanisms found in all the conditions tested. Moreover, aluminum oxides were detected on the worn surfaces, which indicates the presence of an adhesive wear mechanism. The wear behavior of the studied ZX30 alloy showed a greater tendency towards oxidative wear than other Mg alloys, and the microstructure observed strongly affected the wear behavior.

A comparative investigation on microstructure evolution and wear resistance of in situ synthesized NbC, WC, TaC reinforced Mo2FeB2 coatings by laser cladding

To improve the microhardness and wear resistance of Mo2FeB2 coatings, composite coatings were prepared by laser cladding using in situ synthesized NbC, WC, and TaC. The influence of different carbides on the morphology, microstructure, microhardness, residual stress, and tribological properties of the composite coatings was investigated. The results showed various microstructural morphologies in different composite coatings. Apparent herringbone structures were observed in most coatings except for the Mo2FeB2/TaC composite coating and a eutectic structure was formed in the Mo2FeB2/WC composite coating. In addition, the heat-affected zone was typically composed of acicular martensite and lath martensite. The microhardness of the Mo2FeB2/WC composite coating increased to 1543.6 HV0.5 compared with 985.7 HV0.5 observed for the Mo2FeB2 coating. Tensile stress existed in the coating, bonding zone, and heat-affected zone, whereas the substrate exhibited compressive stress. The Mo2FeB2/WC composite coating exhibited the lowest tensile stress (298 MPa). The Mo2FeB2/WC composite coating containing WC and the W2C phase had the lowest coefficient of friction (0.38) and wear rate (3.90 × 10−5 mm3/Nm), indicating its excellent tribological properties. Moreover, the wear mechanism of the Mo2FeB2 coating is severe adhesive and abrasive wear. The adhesive wear mechanism was mitigated by the formation of in situ synthesized NbC, WC, and TaC. The wear mechanism of the Mo2FeB2/WC composite coating was only a slight abrasive wear.

The Effect of Basalt Fiber Addition on Physical Dry Wear in Al-Cu Alloy Used in the Automotive Industry

In this study, AlCu alloy was produced by the powder metallurgy method used in many stages of the automotive industry. In addition to the AlCu alloy, basalt fiber was added. Thus, it is aimed to increase wear resistance. A mixture was obtained with Al and Cu elements used in a 1:1 ratio by weight. Samples that were pressed and sintered at 600°C were examined. Microstructure (scanning electron microscopy), hardness (Vickers), chemical analysis (energy dispersive X-ray), and physical reciprocating wear tests were applied to the samples. Porosity status was observed in the microstructure. The porosity ratio increased with the addition of fiber. With this process, a slight decrease in hardness occurred. During the chemical analysis process, the oxide level of the grains and the alloy was determined to be at most 1%. In the physical dry abrasion test, the abrasion resistance increased by about 6 times with the addition of basalt fiber. Thus, with the addition of fiber in the AlCu alloy, an adhesive wear mechanism has been developed and the wear rate has decreased.

Ecofriendly Protic Ionic Liquid Lubricants for Ti6Al4V

Three diprotic ionic liquids (PILs) containing bis(2-hydroxyethyl) ammonium cations and citrate (DCi), lactate (DL), or salycilate (DSa) hydroxy/carboxylate anions were studied as lubricants for Ti6Al4V–sapphire contact. At room temperature, the neat PILs are non-Newtonian fluids, which show up to a 70% friction coefficient reduction with respect to water. New aqueous lubricants were developed using PILs as 1 wt.% additives in water. The new (Water + 1 wt.% PILs) lubricants showed friction reductions of higher than 50% with respect to water at room temperature. The lowest friction coefficients at room temperature were achieved with thin lubricant layers deposited on Ti6Al4V using Water + 1 wt.% PIL after water evaporation. At 100 °C, the best tribological performance, with the lowest friction coefficients and wear rates, was obtained for the PILs containing aliphatic anions: DCi, and DL. The surface layers of the sapphire balls with mild adhesion and abrasion wear mechanisms were observed via scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS).

Selection of New Heat Treatment Conditions for Novel Electroless Nickel-Boron Deposits and Characterization of Heat-Treated Coatings

Electroless nickel-boron coatings were deposited from a novel deposition bath that was stabilizer-free. Those coatings were analyzed by DSC to determine the crystallization temperature of nickel-boride phases, and then the best heat treatment conditions for the new coatings were selected using the Knoop hardness test and XRD. The results of DSC analysis and XRD were coherent with the findings of previous studies, which shows that the new coating has a boron content lower than 4% wt. The maximum hardness was obtained after heat treatment at 300 °C for 4 h and reached 1196 ± 120 hk50, which is much higher than the as-deposited coating. The heat-treated coatings were then fully characterized using optical and scanning electron microscopy, as well tribological and corrosion tests. Various sliding tests (ball-on-disk and ball-on-flat configurations) were conducted to analyze the coefficient of friction (COF) and wear behavior of the coatings. The maximum von Mises stress was calculated, and values of 624 MPa and 728 MPa were obtained for the ball-on-disk and ball-on flat, respectively, at a depth close to 14 µm from the surface, confirming the suitability of the applied load. Abrasive, adhesive, and fatigue wear mechanisms were observed on the worn sample morphology using SEM. It has been determined that during the corrosion test the OCP and corrosion potential values for the heat-treated coating increase as compared with the as-deposited one, whereas its corrosion resistance decreases.

Functionally Gradient Coatings from HfC/ HfTaC2 to Ti: Growth Process, Basic Mechanical Properties and Wear Behavior

HfC and HfTaC2 coatings with gradient composition manufactured by double-cathode glow discharge plasma surface metallurgy technology were designed to improve the wear resistance of TA15 titanium alloy. The deposition mechanism of plasma and diffusion mechanism of atoms were investigated, and the growth process of coatings was revealed. The mechanical properties comprising microhardness and elastic modulus were investigated via first-principles calculations and experimental verification. The results reveal that the wear resistance of HfC and HfTaC2 coatings with abrasive wear mechanism is always better than that of the substrate with abrasive wear, adhesive wear and oxidation wear mechanism. The volume wear rates of the coatings are reduced by 90%–97% compared with the substrate, and that of HfTaC2 coatings are reduced by 29.9%–45.5% compared with HfC coatings. Furthermore, V-shaped cross section profiles of wear scars formed on HfC coatings, and U-shaped on HfTaC2 coatings, which is attributed to the addition of tantalum which causes HfC to form a sufficient solid solution, a 0.187–0.030 Å elongation of Ta-C bond length and 0.039–0.051 Å shortening of Hf-C bond length led to the unit cell shrinkage and the Bragg lattice changes from face-centered cubic to face-centered square lattice; accordingly, hardness and wear behavior were further improved.

Wear and Mechanical Behavior of ZA27 Alloy Reinforced with B4C Produced by Powder Metallurgy Method

In this study, ZA27 matrix alloy was reinforced with nano-sized B4C and its wear behavior and mechanical properties were investigated. The samples were produced using the powder metallurgy technique. The reinforcement ratio (0, 0.125, 0.5, 1, 2, and 3% by weight) the internal structure, morphology, and wear surfaces were investigated and by SEM analysis and X-ray diffractometer (XRD). Wear tests were carried out in a dry friction environment using 1, 2, 5, and 10 N loads. The results showed that the increased B4C reinforcement increased the abrasion resistance of the composite samples, especially under 10 N load, the weight loss was 250 mg in the matrix material, while it was measured as 0.023 mg in the 3% B4C reinforced sample. As a result of this, while the B4C reinforcement increased, the weight losses decreased under all loads. Although, all the wear types changed from adhesive to abrasive wear when the adhesive wear mechanism was more dominant for ZA27 alloy and had a lot higher weight loss composites. Essentially, reinforcement with nano B4C particles changed the mechanism to abrasive wear. The increase in nano B4C content resulted in the changing of wear from two-body to three-body abrasion.

Wear Characteristics of Wire-Arc Additive Manufactured SS308L

Abstract Wire arc additive manufacturing (WAAM) is an efficient metal additive manufacturing technology. It can be easily accomplished with a gas metal arc welding (GMAW)—cold metal transfer (CMT) machine due to low heat input and low spatter generation characteristics. Austenitic stainless steel (ASS 308L) single thin walls were fabricated using ER308L filler wire having 1.2 mm diameter. The wear summary of the WAAM-processed 308L ASS under dry sliding at severe loading conditions is presented. Wear tests were done under dry (unlubricated) conditions, using a typical high-load pin-on-disc tribometer. AM-ASS processed with a lower heat input exhibited a low coefficient of friction (COF) and wear-rate. The microhardness is observed to be reducing steadily from the bottom layer to the top layer along the building direction to roughly 11.73%, 10.09%, and 8.44% in low, medium, and high heat input, respectively. This is attributed to the thermal history experienced by the material. X-ray diffraction (XRD) analysis of wear debris reveals that martensite is the most prevalent phase. In the wear behavior of AM-ASS, austenite transforms into martensite due to the metastability of ASS during plastic deformation. At severe stresses, plastic deformation of sliding surfaces is more prevalent. Ferrite (%) concentration decreases with the increasing load due to increased plastic deformation, which converts austenite to martensite. As deformation wear debris rolls, it hardens, fractures, and becomes cylindrical, which confirms the adhesive wear mechanism.

Investigation of corrosion-time effects on fretting wear behaviours of copper-magnesium alloy

The premature failure of integral droppers was attributed to the environmental corrosion and fretting wear due to mechanical vibration. Due to its complex working environment, the research on the fretting wear of corroded copper-magnesium alloy is rarely reported in the literature. In this work, an experiment was designed to investigate the effect of corrosion time on the fretting wear behaviours of the copper–magnesium alloy (CuMg0.4) used in integral droppers. The running conditions fretting map of CuMg0.4 at dry conditions and room temperature were successfully constructed by fretting wear tests. Representative testing parameters from different fretting regions (i.e. partial slip, mixed slip and slip regimes) were selected to carry out fretting tests using the CuMg0.4 cylinder after salt spray corrosion for the first time. The running characteristics, wear morphologies and fretting damage mechanisms of tribo-pairs were analysed. Results indicated that the fretting wear mechanisms of CuMg0.4 included adhesion, oxidation, abrasive and fatigue wear mechanisms. After corrosion, the oxide layer on the matrix surface could avoid cracks in a short time, but with increased corrosion time, the overall wear degree of the specimen deepened, and the damage was aggravated. This work further provides theoretical basis for failure analysis and other aspects of integral droppers.

Understanding the mechanisms of adhesive wear for heterogeneous materials through atomistic simulations

When two rough surfaces slide against each other, two main behaviors can be observed at the asperity level: A ductile behavior where the asperities tend to smooth out or a brittle behavior where the asperities detach and form debris. Recently, a critical length scale controlling the transition between both behaviors was identified. Its formulation depends only on material properties and a geometrical factor (of the order of unity). This finding was achieved thanks to molecular dynamics (MD) simulations with hardness-tunable interatomic potentials. However, the materials studied so far have been homogeneous. Here, the work is extended to a class of simple heterogeneous materials with random fluctuations of their properties. A comparative study of the heterogeneous materials against an equivalent homogeneous material is conducted to study the influence of the local variations on the global behavior. It is found that the critical junction size formula works well for hard materials up until a certain ductility threshold after which a third behavior, mixing shear localization and mode II crack opening, appears. There is a transition zone, larger for the heterogeneous material, from the ductile to the brittle behaviors due to local fluctuations and non-deterministic nature of finite temperature atomistic simulations. Local fluctuations render the heterogeneous material weaker than the equivalent homogeneous material and thus, following the critical junction size formula, should lower the probability of forming debris. While this effect can be observed in the single asperity simulations, its magnitude is lower than expected, hinting at the dichotomic effect of local variations: while they increase the overall ductility, they also create particularly brittle areas prone to crack nucleation.

Microstructure, toughness, and tribological properties of laser cladded Mo2FeB2-based composite coating with in situ synthesized WC and La2O3 addition

Mo2FeB2-WC-La2O3 composite coatings were prepared using a preplaced method of laser cladding. The forming quality, microstructure, distribution of La, microhardness, fracture morphology, fracture toughness, and tribological properties were examined. The effect of La2O3 on the microstructure and properties of the coatings was analyzed. The results showed that the metallurgical bonding between the coating and substrate was significantly improved. La2O3 had no significant effect on the phases of the composite coatings. The microstructure growth of the La2O3 coating had no obvious direction and a block-like structure. The microstructure was initially refined and then coarsened with an increase in La2O3; La was found to exist at the Mo2FeB2 phase grain boundaries. The microhardness of the Mo2FeB2-WC coating was 1584.6 HV0.5. The microhardness of the composite coating that contained 0.3 wt% La2O3 reached 1494.7 HV0.5; its coefficient of friction (COF), wear rate, and fracture toughness were 0.31, 3.13 × 10−5 mm3/Nm, and 14.35 MPa·mm1/2, respectively. The crack resistance of the composite coating was the highest at 0.3 wt% La2O3 addition. The wear mechanisms of the coatings containing La2O3 were typical abrasive wear, and the coating without La2O3 was a combined mechanism of slight adhesive and abrasive wear. The coating exhibited an evident brittle fracture morphology.

Modeling Adhesive Wear in Asperity and Rough Surface Contacts: A Review.

Wear is one of the most fundamental topics in tribology and adhesive wear is argued as the least avoidable wear type. Numerical techniques have allowed advances in more realistic simulations of adhesive wear mechanisms and promoted our understanding of it. This paper reviews the classic work on wear modeling by Archard and Rabinowicz, followed by a comprehensive summary of the adhesive wear numerical models and techniques based on physical parameters. The studies on wear mechanisms at the asperity level and rough surfaces are separately presented. Different models and their key findings are presented according to the method type. The advantages and deficiencies of these models are stated and future work, such as considering more realistic geometries and material properties for adhesive wear modeling, is suggested.

Graphene derivatives reinforced metal matrix nanocomposite coatings: A review

Due to the extraordinary mechanical, thermal, and electrical properties of graphene, graphene oxide (GO), and reduced graphene oxide (rGO), these materials have the potential to become ideal nanofillers in the electrodeposited nanocomposite coatings. This article provides an overview of literature on the improvements of properties associated with graphene, GO, and rGO-reinforced coatings, along with the processing parameters and mechanisms that would lead to these improvements in electrodeposited metal matrix nanocomposite coatings, where those affected the microstructural, mechanical, tribological, and anti-corrosion characteristics of coatings. The challenges associated with the electroplating of nanocomposite coatings are addressed. The results of this survey indicated that adding graphene into the plating bath led to a finer crystalline size in the composite coating due to increasing the potential development of specific crystalline planes and the number of heterogeneous nucleation sites. This consequently caused an improvement in hardness and in tribological properties of the electrodeposited coating. In graphene reinforced metallic composites, the severe adhesive wear mechanism for pure metallic coatings was replaced by abrasive wear and slight adhesive wear, where the formation of a tribolayer at the contact surface increased the wear resistance and decreased friction coefficient. Furthermore, superhydrophobicity and smaller grain size resulted from embedding graphene in the coating. It also provided a smaller cathode/anode surface ratio against localized corrosion, which has been found to be the main anti-corrosion mechanism for graphene/metal coating. Lastly, the study offers a discussion of the areas of research that need further attention to make these high-performance nanocomposite coatings more suitable for industrial applications.

High-temperature wear behaviour of ZrC/NbC-reinforced CrMnFeCoNi coatings

ABSTRACT Nowadays, studies of high entropy alloys (HEAs) have shown excellent properties. To improve the high-temperature wear resistance of CrMnFeCoNi alloy, refractory carbides (NbC and ZrC, respectively) reinforced CrMnFeCoNi composite coating were prepared by laser cladding (LC), and its wear performance was investigated. The composite coating showed no cracks or other defects that had metallurgical bonding with the substrate. Those coatings exhibited oxidative and adhesive wear mechanisms in reciprocating wear tests at 600°C. In contrast to the strengthening of NbC, the ZrC in the coating rapidly oxidized during high-temperature wear, forming a large amount of ZrO2. These oxides formed in wear promote the formation of a protective film, further improving the oxidation resistance and wear resistance of the coating.

The Effect of TiN, TiAlN, TiCN Thin Films Obtained by Reactive Magnetron Sputtering Method on the Wear Behavior of Ti6Al4V Alloy: A Comparative Study

Titanium-based alloys have gained worldwide application over the past century. However, their low wear resistance remains an unresolved challenge for the Ti6Al4V alloy, which has significant industrial use. Therefore, it is an integral part in material selection and surface treatment in friction-wear applications. Tribological properties are not only material parameters but also system parameters where test conditions are essential. Hardness, roughness and contact conditions of coatings, which are especially important in surface treatments, affect wear modes. In this study, titanium nitride, titanium aluminum nitride and titanium carbon nitride coatings were obtained by unbalanced reactive magnetron sputtering to improve the weak tribological properties of Ti6Al4V alloy. The wear behavior was studied at room temperature in dry conditions. Wear tests were conducted under different loads and different sliding rates, which were followed by comparative analyses of their wear resistances. While the coated samples showed higher wear resistance than the uncoated Ti6Al4V alloy, the lowest wear track width was observed in TiN coating. Depending on the surface properties of the coatings, adhesion, abrasion and oxidation wear mechanisms were observed. It was concluded that a TiN coating could be a material of choice for applications where triple abrasive wear is dominant.

Adhesive transfer operates during galling

In order to reduce cobalt within the primary circuit of pressurised water reactors (PWR’s), wear-resistant steels are being researched and developed. In particular interest is the understanding of galling mechanisms, an adhesive wear mechanism which is particularly prevalent in PWR valves. Here we show that large shear stresses and adhesive transfer occur during galling by exploiting the 2 wt.% manganese difference between 304L and 316L stainless steels, even at relatively low compressive stresses of 50MPa. Through these findings, the galling mechanisms of stainless steels can be better understood, which may help with the development of galling resistant stainless steels.

Improved wear resistance of AISI-1045 steel by hybrid treatment of plasma nitriding and post-oxidation

In this work, high-temperature plasma nitriding is used to improve the surface hardness and wear resistance of AISI-1045 steel. Subsequently, plasma nitrided samples are post-oxidized for 30 and 60 min to investigate its resultant effect. The treated samples are analyzed by X-ray diffraction, Raman spectroscopy, microhardness tester, scanning electron microscopy, elemental dispersive spectroscopy, and ball-on-disc wear tester. The nitrided sample contains a white layer Fe4N,Fe2−3N, and its post-oxidation form hematite Fe2O3 and magnetite Fe3O4phases. A significant improvement in hardness (~1050 HV) is attained for nitrided samples, while post-oxidation causes a small decrease in hardness. The thickness of the nitrided layer is 8.2 µm, and it is further increased to 9.3 and 13.2 µm by post-oxidation due to further diffusion of nitrogen. The thickness of the oxide layer is 1.5 µm and 2 µm. The presence of a white layer causes abrasive wear of sample, whereas sample with post-oxidation shows outstanding wear resistance with adhesive wear mechanism. The friction coefficient of the nitrided sample is further reduced by plasma post-oxidation. This work suggests that detrimental effects of the white layer due to the removal of hard abrasive particles can be avoided by plasma post-oxidation.

Experimental Investigation on the Machinability of PCBN Chamfered Tool in Dry Turning of Gray Cast Iron

Polycrystalline cubic boron nitride (PCBN) tools are widely used for hard machining of various ferrous materials. The edge structure of the PCBN cutting tool greatly affects the machining performance. In this paper, dry turning experiments were conducted on gray cast iron with a PCBN chamfered tool. Both the cutting temperature and the cutting force were measured, and then the surface quality and tool wear mechanisms were analyzed in detail. It was found that the cutting temperature and cutting force increased with the increase in feed rate, depth of cut, and cutting speed. The surface roughness firstly decreased, and then increased with an increase in feed rate. The minimum surface roughness was obtained with a feed rate of 0.15 mm/r which exceeded the tool chamfer width. The PCBN tool wear mode was mainly micro notches on the rake face and micro chipping on the tool chamfer, while the adhesion wear mechanism was the main tool wear mechanism.