Wear Damage Research Articles

3D Printing of Superhydrophobic Objects with Bulk Nanostructure.

The rapid development of 3D printing (or additive manufacturing) technologies demands new materials with novel properties and functionalities. Superhydrophobic materials, owing to their ultralow water adhesion, self-cleaning, anti-biofouling, or superoleophilic properties are useful for myriad applications involving liquids. However, the majority of the methods for making superhydrophobic surfaces have been based on surface functionalization and coatings, which are challenging to apply to 3D objects. Additionally, these coatings are vulnerable to abrasion due to low mechanical stability and limited thickness. Here, a new materials concept and methodology for 3D printing of superhydrophobic macroscopic objects with bulk nanostructure and almost unlimited geometrical freedom is presented. The method is based on a specific ink composed of hydrophobic (meth)acrylate monomers and porogen solvents, which undergoes phase separation upon photopolymerization to generate inherently nanoporous and superhydrophobic structures. Using a desktop Digital Light Processing printer, superhydrophobic 3D objects with complex shapes are demonstrated, with ultralow and uniform water adhesion measured with scanning droplet adhesion microscopy. It is shown that the 3D-printed objects, owing to their nanoporous structure throughout the entire volume, preserve their superhydrophobicity upon wear damage. Finally, a superhydrophobic 3D-printed gas-permeable and water-repellent microfluidic device and a hierarchically structured 3D-printed super-oil-absorbent are demonstrated.

Optimization of several surface treatment processes for alleviating fretting damage of a locking pin

The operational safety and reliability of a variable gauge train are affected by the anti-fretting wear performance of the locking mechanism. The main purpose of this study is to optimize the surface treatment process for a locking pin material under actual service conditions to alleviate fretting damage. Based on the two basic principles of surface strengthening and friction reduction, a substrate (AISI 4135 steel) surface was treated by laser quenching (LQ), plasma nitriding (PN), and bonded MoS2 coating. Systematic fretting wear tests were conducted, and the wear behavior and damage mechanism of various treated surfaces were comprehensively investigated. The results indicate that the wear resistances of the LQ- and PN-treated surfaces were significantly improved, and their main wear mechanisms were abrasive wear, delamination, and oxidation wear. The MoS2 coating exhibits the lowest friction coefficient and energy dissipation due to its self-lubricating property, but it incurs the highest wear rate and failure in the form of plastic deformation. Furthermore, the rough compound layer with a high hardness on the PN-treated surface is conducive to the formation and maintenance of the third-body contact at the fretting interface, consequently resulting in a significant reduction in wear. An optimal surface treatment process for alleviating fretting damage of the locking pin is recommended via comprehensive evaluation, which provides a reference for the anti-fretting protection of related mechanical components.

Fretting wear behavior of the high-carbon high-chromium X210CrW12 steel: Influence of counterbody material

The effect of counterbody material on fretting wear behavior of the high-carbon high-chromium X210CrW12 steel before and after nitriding was investigated. The transformation of hard carbides into nitrides took place during nitriding, and these nitrides acted as new types of hard phases in the nitrided layer. Two counterbody materials (GCr15 steel ball and SiC ball) were used to conduct the fretting wear tests, which contributed to a better understanding of the role of hard phases in fretting wear. The results indicated that the unnitrided samples fretted against SiC balls with much higher hardness had a much lower wear volume and coefficient of friction (CoF), and the primary carbides acted as barriers against the plastic flow of softened matrix material. For the nitrided samples, the different hardness ratios of the two counterbody materials to the nitrides (transformed carbides) led to different wear damage modes, and the samples fretted against the steel balls had higher wear volume under the low loads of 10 N and 30 N. For the samples fretted against the two counterbody materials, the carbides (or nitrides) played different roles during fretting.

Sliding abrasive wear when combining WEDM conditions and polishing treatment on H13 disks over 1045 carbon steel pins

Forging dies are crucial in forging to manufacture accurate workpieces. These dies are generally made of AISI H steel series and hardened and tempered medium carbon alloy steel. Dies are processed by using high-speed milling + polishing or electrical discharge machining + polishing. The surface quality of the workpiece depends on the surface properties of these dies, where surface roughness, material hardness, and wear evolution of their surfaces are critical aspects to consider. This research analyzes different wire electrical discharge machining surface conditions combined with polishing treatment to describe their influence on friction and wear. Wire electrical discharge machining defines the disks’ surface properties in finishing and roughing conditions, and polishing treatment varies in time and paper sand depending on the roughness. Abbott-Firestone curves and Rsk-Rku roughness parameters characterize the surface roughness of each studied configuration. Room temperature pin-on-disk tests were performed to analyze friction coefficients and wear rate for AISI 1045 pins and AISI H13 disks. On average, the highest (0.284) and the lowest (0.201) friction coefficients were found for the combination of finishing wire electrical discharge machining + polishing and roughing wire electrical discharge machining conditions, respectively. Scanning electron microscope images were taken to describe the wear tracks and pin degradation for different sliding abrasive configurations. The diagram correlating the surface morphology and the friction coefficient predicts the wear damage on initial surface conditions, which is crucial in the forging industry to determine tool maintenance or replacement.

Achieving excellent wear and corrosion properties in laser additive manufactured CrMnFeCoNi high-entropy alloy by laser shock peening

The present work aims to fabricate CrMnFeCoNi high-entropy alloy (HEA) possessing outstanding wear and corrosion properties via laser additive manufacturing (LAM) and subsequent laser shock peening (LSP). The surface morphology , microstructure, microhardness and residual stress of LAM-fabricated specimen were characterized before and after LSP. Additionally, sliding wear and electrochemical corrosion experiments were conducted to evaluate the suitability of LSP for improving wear and corrosion resistance . Results indicated that friction coefficients and wear rates of LAM-fabricated specimens obviously decreased after LSP. Both untreated and LSP-treated specimens displayed uniform wear mechanisms, including abrasive and adhesive wear , while the wear damage level of the high-energy LSP-treated specimen was the mildest. Moreover, LSP-treated specimens exhibited lower corrosion current density and higher corrosion potential as compared with the untreated specimen, suggesting an enhancement in corrosion resistance. The hardened surface layer had positive effects on inhibiting furrow and spalling to resist material removal, and the compressive residual stress enhanced the adhesion of tribo-layers on the worn surface to protect the underlying layer from further damage. The grain refinement and compressive residual stress synergistically contributed to form compact passive films, thereby restraining the aggression of corrosive ions to enhance the corrosion resistance. • LAM-fabricated CrMnFeCoNi HEA is treated by LSP. • LSP improves the wear and corrosion resistance of LAM-fabricated CrMnFeCoNi HEA. • The wear and corrosion mechanisms of CrMnFeCoNi HEA treated by LSP are discussed.

An Evaluation of the Tribological Behavior of Cutting Fluid Additives on Aluminum-Manganese Alloys

The introduction of additives enhances the friction and wear reduction properties of cutting fluids (CFs) as well as aids in improving the surface quality of the machined parts. This study examines the tribological behavior of polymer-based and phosphorus-based additives introduced into cutting fluids for the machining of Al-Mn alloys. Ball-on-disc tests were used to evaluate the coefficient of friction (COF) and lubrication failure temperature to study the performance of the additives in the cutting fluids. Surface characterization was performed on the sliding tracks induced on the Al-Mn disc surfaces and used to propose the wear and friction reduction mechanisms. The polymer-based additive possessed a higher temperature at which lubrication failure occurred, displayed comparable COF at a lower temperature under certain conditions, and possessed a steadier tribological behavior. However, the phosphorus-based additive was observed to display lower COF and wear damage from 200 °C till failure. The lower COF values for the phosphorus-based additive at 200 °C corresponded with lower surface damage on the Al-Mn surface. The phosphorus-based additive’s performance at 200 °C could be attributed to the forming of a phosphorus-rich boundary layer within the sliding wear track, resulting in less surface damage on the Al-Mn surface and lower material transfer to the counterface steel ball surface.

Numerical modeling and analysis of thermal and mechanical behavior for ground wire-clamp system under short-circuit current

In the ground wire-clamp system, aluminum armor tape (AAT) or armor rod (AR) is commonly adopted to avoid the wear damage of ground wire. While under the short-circuit current, damage or even breakage of ground wire in suspension clamp due to overheat may occur. However, there still lacks attention on the investigation about this type of damage. In this paper, a finite element (FE) modeling method of the ground wire-clamp system, which was applicable to two cases with AAT and AR, was proposed to discuss the transient thermal and mechanical behaviors. In the modeling of contact points, an improved contact bridge model considering the contact shape characteristics was proposed. The transient temperature rise experiments for ground wire-clamp systems with AAT and AR were carried out to verify the accuracy of models. The results shows that the improved contact bridge model is conducive to obtaining the accurate calculation results. For the analysis of this type of damage, the generated thermal stress cannot be ignored. In engineering, the ground wire twinned by AAT is at risk of overheat or even breakage under the short-circuit current, while using AR can prevent the ground wire in the suspension clamp from damage of overheat.

The Role of Imaging in Femoroacetabular Impingement: History, Current Practices, and Future Applications.

Femoroacetabular impingement (FAI) is one of the most common causes of early hip articular cartilage wear and labral damage, and subsequently leads to the onset of hip osteoarthritis. Cam-type FAI impingement lesions can be best identified with a 90° Dunn lateral radiograph and a cross-table lateral radiograph with 15° of internal rotation; the alpha angle and the femoral head-neck offset are the most used predictive radiographic markers. FAI lesions with pincer impingement are associated with acetabular retroversion and are more difficult to identify on traditional radiographic imaging; however, the presence of a crossover sign, an ischial spine sign, and/or a posterior wall sign can be useful radiographic markers. Advanced imaging modalities such as magnetic resonance imaging (MRI) and/or magnetic resonance arthrography (MRA) can also be beneficial in the evaluation of FAI and labral pathology; MRA is more sensitive than MRI in detecting intra-articular pathology. Computer-assisted navigation for preoperative planning and intraoperative surgical assistance are promising technologies; however, additional studies are needed before they can be utilized safely and effectively.

Wheel profile optimization procedure to minimize flange wear considering profile wear evolution

This study aims to develop a wheel profile optimization procedure to minimize flange wear considering the wear evolution. To this end, the wheel wear simulation capability is integrated into the profile optimization framework such that a total material loss can be minimized under design constraints. This allows for the wear reduction to be maintained over an extended traveling distance, while an optimized profile, minimizing the frictional energy for only the initial profile, would not ensure the optimum performance after the profile wear becomes significant. Furthermore, to enable a balanced mitigation of the profile wear and surface damage, the damage index model is introduced to the weighted objective function, considering profile wear evolution. Using flange wear tests with a scaled roller test rig, wear reduction of the optimized profile is experimentally validated. The wear simulation results agree with the test data. It is demonstrated that the flange wear and tread surface damages are reduced simultaneously over an extended traveling distance using the profile optimization procedure developed in this study.

Tribological Studies of Bamboo Fibre Reinforced Epoxy Composites Using a BOD Technique.

To reduce the emission of harmful materials into the ecosystem, researchers have been exploring the potential of manufacturing polymeric composites based on natural fibres. Although the large area of application of these materials has encouraged investigations of their performance under various loading conditions, less research has been conducted on their tribological behaviour. Hence, in this study, tribological tests were conducted on epoxy composites based on bamboo fibres. The wear performance of bamboo fibre reinforced epoxy was tested using various operating parameters, and the worn surfaces were examined using optical microscopy. The results revealed that the specific wear rate of the composites reduced since the epoxy was reinforced with bamboo fibres. Scanning electron microscopy analysis showed different wear mechanisms and damages.

Effects of solid friction modifier on friction and rolling contact fatigue damage of wheel-rail surfaces

In railway network, friction is an important factor to consider in terms of the service behaviors of wheel-rail system. The objective of this study was to investigate the effect of a solid friction modifier (FM) in a railway environment. This was achieved by studying the friction, wear, and rolling contact fatigue (RCF) damage on the wheel-rail materials at different slip ratios. The results showed that when a solid FM was applied, the friction coefficient decreased. After the solid FM was separated from the wheel-rail interface, the friction coefficient gradually increased to its original level. With the application of the solid FM, the wear rates of the wheel-rail decreased. In addition, the thickness and hardness of the plastic deformation layers of the wheel-rail materials were reduced. The worn surfaces of the wheel-rail were dominated by pits and RCF cracks. Without the FM, RCF cracks ranged from 84 to 120 µm, and subsurface cracks were generated. However, with the FM, RCF cracks ranged from 17 to 97 µm and no subsurface cracks were generated. These findings indicate possible methods of improving the performance of railway rolling stock by managing friction, and reducing wear and permanent RCF damage affecting both the wheels and rails.

Evolution of wear damage in 690 alloy tube mated with 405 stainless steel plate due to fretting conditions

A running condition fretting map of 690 alloy tubes against 405 stainless steel plates was established through various fretting tests at room temperature. Three fretting regimes were observed: partial slip regime (PSR), mixed regime (MR), and gross slip regime (GSR). In the PSR, slight damage associated with the lowest friction coefficient (COF) and an adhesion layer due to adhesive wear were detected. In the GSR, severe damage corresponding to a higher COF and delamination were observed. In the PSR, Fe2O3 may be one of the main components of the wear particles. The spinel oxides of NiCr2O4 and/or FeCr2O4 may have existed in the debris layer in the MR and GSR.

Effects of Bearing Steps on Probable Wear Damage of Main Bearings of an IC Engine

When two bearing shells are assembled in the bearing housing, it is possible that the edges of the two shells do not fit in the radial direction completely and have an offset relative to each other. This assembly error, which can have different causes, is called the bearing step in this paper. The bearing step can lead to wear damage in bearings. The effects of bearing step on the lubrication performance of main bearings and the probable wear damage have been investigated. To calculate the bearing lubrication characteristics such as maximum oil film pressure and minimum oil film thickness, elasto-hydrodynamic model, which includes the mass conservation algorithm, has been applied. The objective of this work is to investigate the effects of bearing steps on the lubrication performance of the main bearings and assess the probable wear damage of main bearings due to bearing step. The prediction of elasto-hydrodynamic model is very proximate to what really happened. The results show that for the under-study 12-cyl engine, main bearing No. 2 involved with medium wear damage. Wear damage in this main bearing No. 3 is not a concern, while main bearing No.4, 5 and 6 do not predict the probability of wear damage. For main bearing No.7, it is concluded that considering step and bore relief in simulation has high importance so that the solution without step and bore relief does not predict the wear, but with step and bore relief predicts medium wear damage.

A comparison of metal/metal and ceramic/metal taper-trunnion modular connections in explanted total hip replacements.

Corrosion and wear are commonly found at the taper‐trunnion connection of modular total hip arthroplasty (THA) explanted devices. While metal/metal (M/M) modular taper‐trunnion connections exhibit more wear/corrosion than ceramic/metal (C/M) modular taper‐trunnion connections, damage is present in both, regardless of material. This study used a combination of assessment techniques including clinical data, visual scoring assessment, optical imaging, profilometry, and x‐ray photoelectron microscopy (XPS), to investigate wear mechanisms and damage features at the modular taper‐trunnion connection of 10 M/M and 8 C/M explanted THAs. No correlation was found between any demographic variable and corrosion wear and assessment scores. All assessment techniques demonstrated that the stem trunnions had more damage than head tapers for both explant groups and agreed that C/M explants had less corrosion and wear compared to M/M explants. However, visual assessment scores differed between assessment techniques when evaluating the tapers and trunnions within the two groups. Profilometry showed an increase (p <.05) in surface roughness for stem trunnions compared to head tapers for both explant groups. X‐ray photoelectron spectroscopy performed on deposits from two M/M explants found chromium and molybdenum carbides beneath the surface while chromium sulfate and aged bone mineral were found on the surface suggesting that the debris is a result of corrosion rather than wear. These results indicate that taper‐trunnion damage is more prevalent for M/M explants, but C/M explants are still susceptible to damage. More comprehensive analysis of damage is necessary to better understand the origins of taper‐trunnion damage.

Slippage effects on the crack behavior of pearlitic steel induced via rolling-sliding friction

The effect of slippage on the crack behavior of pearlitic steel induced by rolling-sliding friction has been investigated to elucidate the wear damage. The results show that the crack-initiated site occurred at sub-surface sites of the severely deformed phase structure — which is due to the exhausted ferrite ductility — and was accompanied by a series of adjacent connected voids. As the slippage increased, more cracks were observed with the dissolved cementite structure, ranging from lamellae to fragments and particles. The slippage effect on the wear and fatigue competition was demonstrated by comparing the crack propagation rate and wear loss of the material during the rolling-sliding friction process. The length and depth of initiated cracks were key parameters in evaluating the wear damage.

Synergistic addition of yttria-stabilized zirconia and h-BN/graphene/diamond restricts multi-scale length wear of Cr-based hybrid coatings

In the current study, electro-deposition of hybrid coatings consisting of Cr simultaneously reinforced with nano-scale 3 mol% yttria-stabilized zirconia (YSZ) along with hexagonal boron nitride (Cr-YSZ-BN), graphene (Cr-YSZ-Gr), and diamond (Cr-YSZ-D) was performed using an environmentally-benign trivalent Cr bath. Abrasive wear with ploughing for scratch test is recognized as the dominant wear mechanism in coatings; on increasing the scratch speed, gross spallation occurs in the BN reinforced coatings. While graphene and diamond were strongly adherent to the substrate with no signs of delamination. During fretting, oxidative and three-body abrasive wear in wedge formation mode with severe crack networking was observed in Cr-YSZ-BN. Micro-ploughing was active with intermittent cracking in Cr-YSZ-Gr coatings, indicating lower wear (via solid-lubrication by graphene). Diamond added coating, on the other hand, exhibits fewer cracks with ploughing. High hardness and elastic modulus with a maximum of ~26 GPa and 245 GPa, respectively, were obtained for Cr-YSZ-D coating with a minimum wear rate of ~3.5×10−11 m3/Nm (fretting) and 3.8×10−5 mm3/Nm (scratching). Further, rigid sp3 hybridization of carbon atoms in Cr-YSZ-D leads to the strong interlocking between Cr matrix and diamond, thereby lowering the wear damage of the coating system. The unique combination and uniform dispersion of YSZ and diamond particles displayed enhanced friction and wear resistance (k ~ 1.4×10−3), primarily due to the inherent high hardness of diamond and matrix strengthening by nano and micro-scale particles. Therefore, Cr-YSZ-D coating system emerges out as a highly robust coating capable of providing enhanced damage tolerance towards wear for various tribological applications.

A Review on Mechanisms and Testing of Wear in Slurry Pumps, Pipeline Circuits, and Hydraulic Turbines

AbstractThis paper presents an overview about particulate wear that occurs in various components of slurry pumps, pipeline systems, and hydraulic turbines due to the mechanical action caused by the flow of solid–liquid mixtures. Three most common wear problems, namely, erosion, erosion–corrosion, and abrasion occur in different industries like thermal and hydro power plants, mining, chemical, and marine industries. Therefore, the efficiency of these industries and power plants highly depends on the wear damages. So, it becomes necessary to govern the wear phenomenon. In this paper, the various properties of particles and target are discussed on which the particulate wear depends. Present overview explains the experimental methods of measuring the particulate wear at in situ and ex situ conditions by using the different types of testers, rigs, and pilot plant test loops. Moreover, the empirical and analytical correlations or models for the prediction of particulate wear in pumps, piping circuits, and hydraulic turbines are also discussed in present literature review. By studying the all possible advantages and disadvantages, the gaps in knowledge of wear prediction methods and models are highlighted. At the end, a “think-model” for the prediction as well as reduction of wear in the various components is presented on the basis of different experimental and computational fluid dynamics (CFD) based simulation work. Further investigations can be carried out to develop the more accurate and flexible models that can be used to predict the particulate wear in a wide range of applications.

A study of the wear damage of a PTFE coating: The effects of temperature and environment on its mechanical and tribological properties

In this study, a methodology was set up to obtain a measure of the durability of PTFE coatings. Tribological tests to study the effect of both temperature (from 25 °C to 180 °C) and environment (dry, in water, and in oil) on the mechanical and tribological properties of PTFE were carried out. Interactions between the effects of temperature and environment were also investigated. As expected, the experimental results showed that the wear resistance of PTFE significantly decreases with an increase in temperature. Measurements of the mechanical properties of the coatings by nanoindentation at different temperatures confirmed a change in the mechanical properties of the PTFE coatings with increasing temperature. The tribological properties were evaluated through the evolution of the coefficient of friction as a function of temperature and the morphological study of wear debris by scanning electron microscopy (SEM). In addition, the coefficient of friction exhibits no significant difference as a function of the environment. Examination of transfer film formed under various conditions helped us understand the various wear mechanisms occurring during these tests and indicated that the formation of an adhered and persistent transfer film was directly linked to the wear performance of the PTFE coating. In particular, higher wear observed in the oil environment could be attributed to a different tribological behavior of the transfer film on the abrasive counterface, namely poor adhesion, resulting in an ease of removal and replenishment with successive rubbing cycles.

A Markov regenerative process model for phased mission systems under internal degradation and external shocks

Recently, phased mission systems (PMSs) have been widely studied due to their wide range of applications, such as man-made satellites or spacecraft. The lifetime of the PMSs can be separated into several phases, in which their tasks, system configurations, and failure criteria could be different. Meanwhile, the randomly occurred shocks, such as the space radiation from outer space, will cause additional wear and fatal damage on the electronic devices in these systems, which will obviously affect the system reliability. To consider these shocks’ effect in the reliability modeling of the PMSs, a Markov regenerative process (MRGP) based model is proposed in this paper. Firstly, shock models for components and the basic conceptions of MRGP are introduced. Then, a simple cold standby system is used to show the proposed MRGP model for systems under mixed shocks. And a Monte Carlo simulation procedure is applied to verify the results. At last, by integrating the proposed MRGP model and the modular method for PMSs, the reliability of an AOCS in a spacecraft is assessed to show the proposed method.

Tribological properties of Ni–B–TiO2 sol composite coating elaborated by sol-enhanced process: abrasive wear and impact wear

Abstract The development of composite coating with higher dispersive second phase is a crucial goal to achieve its performance against wear. In this respect, an interesting experimental investigation on the behavior of Ni–B–TiO2 sol composite coating towards scratching, sliding and impact loadings was performed. The adhesive strength was determined by progressive scratch test, while the tribological behavior was assessed through rotating and reciprocating sliding tests, as well as the impact-sliding tests. The in-situ formation of TiO2 nanoparticles in Ni–B bath, which is a recently invented technique, significantly improves the scratch response of the composite coating and its abrasive wear resistance. Indeed, the composite coating appears exempt from delamination after both scratch tests and pin-on-disk test, contrary to the pure Ni–B coating. Regarding the impact wear resistance, it was found that the wear severity and damage mechanisms depend strongly on the impact angle, which in turn is controlled by the solicitation type. The SEM observations accompanied with EDS analysis were carried out inside the wear scars to clearly understand the relationship between the surface damage and the contact angle.