Severe Wear Research Articles

An Experiment Study on Surface Topography of GH4169 Assisted by Ultrasonic Elliptical Vibration Ultra-Precision Turning

Nickel-based superalloys (GH4169) are a typical difficult-to-machine material with poor thermal conductivity and severe work hardening. They are also prone to poor surface quality, severe tool wear, and poor machinability, which affect their performance. In this paper, an experimental study of GH4169 ultrasonic elliptical vibratory ultra-precision cutting was carried out. The experimental results show that ultrasonic elliptical vibratory cutting (UEVC) significantly reduces surface roughness and improves surface quality compared to conventional cutting (CC). The effects of cutting parameters such as cutting speed, feed rate, cutting depth, ultrasonic amplitude, and tool nose radius on the surface roughness of GH4169 workpieces were further investigated in UEVC. Based on the analysis of the experimental data, the optimal combination of parameters for GH4169 ultrasonic elliptical vibration ultra-precision cutting was determined: cutting speed of 3 m/min, feed rate of 16 μm/rev, cutting depth of 2 μm, ultrasonic amplitude of Ay = 3.0 μm, Az = 0.8 μm, and a tool nose radius of 0.8 mm. This parameter combination improves the machining quality of GH4169 and provides a valuable reference for the subsequent development of ultrasonic elliptical vibratory cutting for other difficult-to-machine materials.

Understanding Electric Current Effects on Tribological Behaviors of Instantaneous Current-Carrying Pair with Recurrence Plot

Abstract Armature-rail instantaneous current-carrying friction in electromagnetic launchers refers to a sliding electric-mechanical impact friction and transition-induced arc erosion on a millisecond time scale. To reveal the electric current (50 to 300 A) effects on friction behavior and wear mechanism, the instantaneous current-carrying friction tests were performed with Al 1060 and Brass H62. Given the short nonlinear friction-induced signals, the friction behavior, including the time-domain information and system state, was comprehensively analyzed via frictional sound pressure (FSP), recurrence plot (RP), and recurrence quantification analysis (RQA). The wear topography was observed, and characterized by the multifractal spectrum. Recurrence analyses demonstrate that as the current increases, the nonstationarity of the system state weakens, and the complexity and unpredictability enhance. Higher currents reduce the FSP amplitude, i.e., enhance the interfacial lubrication effect, but intensify electrical wear and surface roughness. This signifies a wear mechanism transition from abrasive wear and slight adhesive wear to arc ablation, fatigue wear, and severe adhesive wear. The widening spectrum width implies that the irregularity and fluctuation of the topography are enhanced with the current. RP patterns and RQA quantifiers correlate with the wear damage state. The results provide a reference for anti-wear design and online degradation tracking of the rail.

The impact of dual ceramic components (WC/B4C) on the friction performance of copper-based powder metallurgy friction materials and wear mechanism

The copper-based powder metallurgy friction material, modified with dual ceramic components (WC/B4C), underwent friction experiments paired with custom-made carbon ceramic discs. The overall findings are as follows: The judicious addition of dual ceramic components (WC/B4C) can enhance the mechanical, thermal, and frictional performance of copper-based powder metallurgy friction materials. When the WC/B4C ratio is 5:3, the material exhibits the optimal mechanical, thermal, and frictional properties. B4C and WC, after braking, form friction films of B2O3 and WO3. Additionally, the friction film of copper-based powder metallurgy friction materials can be categorized into an oxide layer, a deformation layer, and a matrix layer. The oxide layer primarily consists of Fe2O3, the deformation layer is mainly composed of WO3 and B2O3, and the matrix layer is primarily composed of CuO and Cu2O. With the increase in the WC/B4C ratio, the primary wear mechanisms of copper-based powder metallurgy friction materials shift from abrasive wear to mild fatigue wear, mild fatigue wear progressing to severe fatigue wear, adhesive wear, and fatigue wear, accompanied by a gradual intensification of oxidative wear.

Comparative study on fretting friction and wear characteristics of different impregnated graphite for sealing application

Impregnated graphite has attracted considerable attention and has been widely used as an ideal sealing material in many fields. However, the service environment often contains vibrations, which can easily lead to severe fretting wear and leakage. In this study, the fretting friction and wear properties of resin-impregnated graphite and antimony-impregnated graphite were investigated. The results revealed that only gross slipping regime (GSR) occurred for two impregnated graphite. For resin-impregnated graphite, both abrasive and adhesive wear were discovered. Yet slight fatigue wear occurred on the worn surface of antimony-impregnated graphite at higher cyclic contact stress. The significant properties of the impregnated graphite can be attributed to a transfer film, which uniformly and stably adsorbs on the contact interfaces. This study provides an important basis for matching the industrial applicability of graphite-based modified sealing materials.

Resistance of CAD/CAM composite resin and ceramic occlusal veneers to fatigue and fracture in worn posterior teeth: A systematic review.

Severe tooth wear is related to substantial loss of tooth structure, with dentin exposure and significant loss (≥1/3) of the clinical crown. The objective of this systematic review was to summarize and analyze the scientific evidence regarding the mechanical performance of computer-aided design/computer-aided manufacturing (CAD/CAM) composite resin and CAD/CAM lithium disilicate ceramic occlusal veneers, in terms of fatigue and fracture resistance, on severely worn posterior teeth. Currently, occlusal veneers are an alternative for treating worn posterior teeth. Although scientific evidence demonstrates the good performance of lithium disilicate occlusal veneers, there are less brittle materials with a modulus of elasticity more similar to dentin than ceramics, such as resin CAD/CAM blocks. Therefore, it is important to identify which type of material is best for restoring teeth with occlusal wear defects and which material can provide better clinical performance. This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive search of the PubMed, Embase, Web of Science, Scopus, Cochrane, OpenGrey, Redalyc, DSpace, and Grey Literature Report databases was conducted and supplemented by a manual search, with no time or language limitations, until January 2022. We aimed to identify studies evaluating the fatigue and fracture resistance of CAD/CAM composite resin and ceramic occlusal veneers. The quality of the full-text articles was evaluated according to the modified Consolidated Standards of Reporting Trials (CONSORT) criteria for in vitro studies, and 400 articles were initially identified. After removing duplicates and applying the selection criteria, 6 studies were included in the review. The results demonstrated that the mechanical performance of CAD/CAM composite resin occlusal veneers is comparable to that of CAD/CAM lithium disilicate occlusal veneers in terms of fatigue and fracture resistance.

Tool wear monitoring strategy during micro-milling of TC4 alloy based on a fusion model of recursive feature elimination-bayesian optimization-extreme gradient boosting

Online monitoring of tool wear is an indispensable part of industrial production. It allows for real-time assessment of tool condition, enabling tool replacement at the optimal time. This not only reduces the time costs associated with downtime for inspections but also effectively prevents the deterioration of workpiece quality due to excessive wear. Therefore, online monitoring of tool wear is essential for ensuring machining quality and efficiency. This research presents a monitoring technique for tool wear while performing micro-milling by extracting features from machining signals. Initially, the wear mechanism, which includes initial, regular, and severe wear, is analyzed. Tool wear labels are then constructed. Subsequently, the recursive feature elimination (RFE) algorithm optimizes the original feature set from the processed signal, resulting in a subset of relevant features that accurately describe the tool wear. The optimal subset is utilized as an input vector for extreme gradient boosting (XGBoost) training. Next, the best hyperparameter combination for the monitoring model is determined using Bayesian optimization (BO), ensuring the generalization performance of the monitoring model. Finally, the two-edge wear monitoring model is established based on the RFE-BO-XGBoost. To validate the superiority of the RFE-BO-XGBoost model, the performance of the XGBoost model with default parameters in tool wear monitoring is also investigated. The results demonstrate that the constructed monitoring model can effectively identify the tool wear stage. More notably, it precisely predicts the wear status of two cutting edges simultaneously, enabling qualitative and quantitative monitoring of tool wear under normal manufacturing settings.

Phase alteration in Zr, Nb, Mo-doped Fe2Ni2CrV0.5 high-entropy alloy for mechanical performance regulation: A parallel comparison of tribological behavior against GCr15 counterpart

The microstructure, microhardness, and the tribological behavior of Zr, Nb and Mo-doped Fe2Ni2CrV0.5 high-entropy alloy (HEA) coatings prepared by laser cladding were investigated and compared in parallel. The Nb-doped coating with 86 % volume fraction Fe2Nb Laves phase containing only three slip systems exhibits superior tribological properties than Zr-doped coating which has 78 % proportion of FCC phase. The Nb-doped coating with microhardness of 745 HV is invulnerable to wear loss due to triple constraint effect of dislocation movement, while the Zr-doped coating is susceptible to severe delamination wear owing to the lower microhardness (287 HV) compared to the GCr15 counterpart (650 HV). The Mo-doped coating with the microhardness of 585 HV presents the best wear resistance, which is attributed to the strength-toughness synergistic effect caused by σ phase and alternating arrangement eutectic nanoscale lamellar structure (FCC/σ). Relatively large microhardness difference leads to the abrasive chips adhesion phenomenon between the coatings and the GCr15 counterpart, except for the friction pair of Mo-doped coating/GCr15.

Study on Flat Die Wear Characteristics in Flat Die Pelletizing with Different Material Ratios Based on DEM-FEM

Wear can occur in flat die pelletizers, often reducing service life. This study explores the issue of die hole wear in the pelletizing process of a standard Total Mixed Ration (TMR) feed. The selected TMR formulation comprises varying proportions of corn, alfalfa hay, and quinoa. A coupled DEM-FEM analysis was used to examine stress–strain conditions in various die hole regions at different material ratios, predict the fatigue life of flat die materials in the pelletizing process, and validate the accuracy of investigating flat die wear through friction wear tests. It was found that the entrance of the die hole experiences the most severe conditions in terms of equivalent stress and elastic strain. The fatigue life is shortest at the entrance, with a maximum equivalent stress of 42.8 MPa, a maximum equivalent elastic strain of 2.5 × 10−3, and a minimum fatigue life stress cycle of 5.0 × 105. In contrast, the equivalent stress and equivalent elastic strain at the middle and upper parts of the die hole are minimal, with an equivalent stress of 4.8 MPa and a minimum equivalent elastic strain of 2.8 × 10−4. Material wear tests revealed that the most severe wear on the flat die specimen occurred when the ratio of corn, alfalfa hay, and quinoa straw was 7:2:1, consistent with the findings from the DEM-FEM coupling method. The pelleting process, arising from the contact between the material and metal, encompasses adhesive wear, abrasive wear, and fatigue wear.

Comparative Study of the Tribocorrosion Performance of NiTiNOL60 in Acidic, Alkaline, and Saline Environments

AbstractIn order to enhance the durability of tribological interfaces, an investigation into the synergistic effects of sliding wear, corrosion, and their interactions is crucial. This study focuses on understanding the deformation mechanisms of NiTiNOL60, a nickel-rich nickel-titanium alloy, during sliding against Al2O3 in different corrosive environments, including acidic, alkaline, and saline mediums. The pH of the environments is found to play a significant role in the tribocorrosion process, leading to electromechanically induced transformations and various wear patterns. Plastic deformations are observed on the wear track surfaces, particularly in the severe and mild wear regimes. In an alkaline environment, depassivation of the oxide layer triggers oxidational wear, with the depassivation rate dependent on factors like contact pressure, sliding velocity, and passive film properties. The wear volume is highest in saline environments, with contributions from mechanical wear, corrosion, and third-body abrasion. Grain deformations occur in the alkaline environment due to shear forces, while in the acidic medium, corrosion accelerates mild wear involving abrasion and delamination. The findings provide insights into wear mechanisms and localized corrosion, highlighting the influence of H+ and OH− groups (pH values) on corrosive wear and crack propagation.

Effects of Adding Graphite to Epoxy Resin on its Mechanical Properties and Mild-to-Severe Wear Performance at its Heat Distortion Temperature

In this study, epoxy/graphite composites were fabricated based on different weight fractions (0, 3, 6, and 9 wt.%) of graphite powder for bearing applications. The mechanical and tribological properties were assessed. Adhesive wear tests covered the severe regions, where the interface temperature (IFT) exceeded the heat distortion temperature (HDT) of the epoxy. Graphite additions improved elastic modulus and hardness but decreased fracture strain and toughness of the composites. The tribological behaviors in the mild wear region were improved as the graphite content increased. In the mild wear region, the increase in graphite additions showed a good improvement by reducing the specific wear rate (SWR) and coefficient of friction (COF). In the severe wear region, the neat epoxy and higher graphite concentrations exhibited a dramatic increase in SWR, whereas the lowest addition of 3 wt.% exhibited good wear performance. For epoxy, the reason was that IFT exceeded its HDT, while the aggregation of graphite particles was the main reason in the case of higher graphite concentrations. SEM examinations showed severe wear signs—high ploughing and fracture—when IFT exceeded the HDT. However, by reducing the IFT, graphite additions did not show such severe wear features due to the accelerated heat dissipation.

Design and Performance Prediction of a Vortex Pump Based on CFD for High Concentration Sludge Dredging

Abstract Aiming at solving the problems of clogging and severe wear of the delivery pump in the sludge dredging project, a design method for a vortex pump was summarized. An open impeller and a cross shaped blade was designed with good passing ability, simple structure, and easy maintenance. The volute flow path profile of the vortex pump was designed as a spiral, and the relationship between the width of the vaneless cavity and the diameter of the impeller was established. Based on CFD, the external characteristics of the DRC45-200-VLS vortex pump were simulated and predicted, with a flow rate of 600 m3/h, a head of 20 m, and a water efficiency of 50%. The effects of medium viscosity, solid phase distribution, and gas phase distribution on the flow field of the vortex pump were analyzed. The results showed that the designed vortex pump had good adaptability to transport high concentration sludge and aerated sludge. Combined with a municipal sludge dredging project, a vortex pump transportation scheme for high concentration sludge dredging was formed.

Advanced hybrid composites: A comparative study of glass and basalt fiber reinforcements in erosive environments

AbstractThis study looks at how erosive wear affects hybrid composites made by vacuum infusing glass and basalt fibers into an epoxy matrix. The study uses garnet abrasives and a design experiment method to test how resistant these hybrid composites are to erosion at 30°, 60°, and 90° angles of impact. The analysis included three‐dimensional profilometry and scanning electron microscopy. Results show that glass layers enhance erosion resistance, whereas basalt layers increase wear. Key quantitative findings include erosion rates and mass loss, highlighting impingement angle and erosion time as critical factors. At a 30° angle, basalt exhibited more severe wear (erosion rate: 0.8090 mg/g for 20 s) compared to glass (erosion rate: 0.5683 mg/g). Conversely, at 90°, the erosion rate for basalt decreased to 0.3643 mg/g, indicating a decreased sensitivity to this steeper angle. According to the ANOVA, impingement angle and erosion time account for 30.08% and 50.25% of the erosion rate variance, respectively. These findings advance our understanding of material behavior in hybrid composites and emphasize the strategic selection and layering of materials for enhanced durability. This research contributes to developing more sustainable composites, demonstrating natural fibers' potential to improve mechanical properties and erosion resistance.Highlights Glass layers enhance durability against erosive forces in hybrid composites. Basalt layers accelerate erosion rates, showing a need for strategic layering. Glass fiber reinforcement significantly improves wear performance. Hybrid constructions with glass a top basalt balance flexibility and durability. Emphasizes eco‐friendly advantages of natural materials in composites.

A preliminary study on generation of axle box vibration spectra for metro vehicles in China using the developed spectral synthesis method

ABSTRACT In-service metro vehicles in China exhibit diverse vibration behaviours. This study focuses on analysing the vibration characteristics of these vehicles, with a particular focus on the complex non-stationary axle box vibrations measured on-site, as they closely correlate with wheel-rail interaction dynamics. A developed PSD-based synthesis method is first proposed to quantify the axle box vibration. The axle box vibration spectra of the metro vehicles in China are then generated from the measurements for various vehicles. Furthermore, a multi-line segment flat spectrum, designed specifically for the shaker loading, has been produced. The results show that the proposed method can determine the parameters (segment number, quantile) by the energy conservation law, which avoids the empirical value selection in previous methods and can be effectively utilized to generate the vibration spectra of the axle box. In addition, a notable distinction exists between the IEC 61,373 standard spectrum and the axle box vibration spectra of Chinese metro vehicles. While the former represents a single-peak spectrum ranging from 20 ~ 100 Hz, the latter consists of a multi-peak spectrum with peak frequency bands exceeding 100 Hz. The wear condition of the wheel-rail surface has a pronounced contribution to the vibration spectral magnitude. In cases of wheel-rail surface severe wear, the vibration spectrum values in the Z direction surpass the standard spectrum values across most frequencies, with the highest spectral value notably observed within 50 ~ 200 Hz. Such observations should be thoroughly taken into account in the analysis of fatigue damage to mounted equipment.

Effects of chip breaker groove and tool nose radius on progressive tool wear and behavior when turning GH3536 nickel-based superalloys

Nickel-based superalloys are typically challenging to machine and often exhibit severe tool wear during the turning process, thus attracting substantial research attention. This study not only explores the tool wear mechanisms when turning GH3536 nickel-based superalloys but also introduces a focus on the role of tool geometry configuration. Tools with different chip breaker groove structures and nose radii were investigated, with results indicating the tool wear mechanisms were predominantly abrasive and adhesive. For the 04HA chip breaker, which has a 9° rake angle and a "V"-shaped bottom, there is a single point of impact with the chip during cutting, while the 04VP3 chip breaker, with a 15° rake angle and a flat bottom, has two points of impact with the chip during cutting, increasing chip deformation and favoring chip breaking, thereby suppressing the formation of built-up edge. Additionally, changes in the nose radius influenced the degree of work hardening and consequently influence the severity of notch wear, with the nose radius also impacting the chip flow angle. Based on this finding, a theoretical mathematical model describing the initial chip flow angle was established and validated. Additionally, an examination of the effects of varying operating parameters on tool life was conducted, revealing that cutting speed was the most significant factor affecting tool life, followed by feed rate and depth of cut.

Improvements in Wear and Corrosion Resistance of Ti-W-Alloyed Gray Cast Iron by Tailoring Its Microstructural Properties.

The improved wear and corrosion resistance of gray cast iron (GCI) with enhanced mechanical properties is a proven stepping stone towards the longevity of its versatile industrial applications. In this article, we have tailored the microstructural properties of GCI by alloying it with titanium (Ti) and tungsten (W) additives, which resulted in improved mechanical, wear, and corrosion resistance. The results also show the nucleation of the B-, D-, and E-type graphite flakes with the A-type graphite flake in the alloyed GCI microstructure. Additionally, the alloyed microstructure demonstrated that the ratio of the pearlite volume percentage to the ferrite volume percentage was improved from 67/33 to 87/13, whereas a reduction in the maximum graphite length and average grain size from 356 ± 31 µm to 297 ± 16 µm and 378 ± 18 µm to 349 ± 19 µm was detected. Consequently, it improved the mechanical properties and wear and corrosion resistance of alloyed GCI. A significant improvement in Brinell hardness, yield strength, and tensile strength of the modified microstructure from 213 ± 7 BHN to 272 ± 8 BHN, 260 ± 3 MPa to 310 ± 2 MPa, and 346 ± 12 MPa to 375 ± 7 MPa was achieved, respectively. The substantial reduction in the wear rate of alloyed GCI from 8.49 × 10-3 mm3/N.m to 1.59 × 10-3 mm3/N.m resulted in the upgradation of the surface roughness quality from 297.625 nm to 192.553 nm. Due to the increase in the corrosion potential from -0.5832 V to -0.4813 V, the impedance of the alloyed GCI was increased from 1545 Ohm·cm2 to 2290 Ohm·cm2. On the basis of the achieved experimental results, it is suggested that the reliability of alloyed GCI based on experimentally validated microstructural compositions can be ensured during the operation of plants and components in a severe wear and corrosive environment. It can be predicted that the proposed alloyed GCI components are capable of preventing the premature failure of high-tech components susceptible to a wear and corrosion environment.

Intraoral wear of PICN CAD-CAM composite restorations used in severe tooth wear treatment: 5-year results of a prospective clinical study using 3D profilometry

ObjectivesTo evaluate, in a prospective clinical study over 5 years with ex vivo 3D profilometry analyses, the intraoral wear of Polymer-Infiltrated Ceramic Network (PICN) CAD-CAM composite restorations used in severe tooth wear treatment with the One-Step No-Prep technique. Methods192 PICN (Vita Enamic) restorations on molars and premolars were included in a prospective clinical study involving patients treated according to the One-step No-prep protocol (n = 7). All patients showed clinical signs of bruxism. Replicas of restorations on molars and premolars were realized at each evaluation time (baseline and then every year up to 5 years) and scanned to perform 3D profilometry. Baseline and recall scans were superimposed with Geomagic Control software. The mean material wear was calculated for the full occlusal area (FOA) and for the occlusal contact area (OCA), respectively. Clinical evaluation of restorations was performed at recall. ResultsAt 5 years, the estimated mean material wear for FOA was inferior to the accuracy threshold of the profilometry measurement chain. For OCA, the estimated mean wear of the material was – 27.97 µm. This material wear was shown to be significantly influenced by time (p < 0.0001) and patient (p = 0.026), while the type of tooth (molar or premolar) had no influence. At 5 years, the survival and the success rates of restorations were 99.48% and 90.62%, respectively. SignificanceThe PICN material exhibits a low wear process in the treatment of severe tooth wear despite the presence of clinical signs of bruxism, and it constitutes a suitable material for the One-step No-prep technique.

Resultater fra rapportering til Bivirkningsgruppen 2023

English summary Nor Tannlegeforen Tid. 2024; 134: 418-24. This case study describes the oral rehabilitation of a patient with severe wear on teeth and restorations. A successful rehabilitation was achieved with emphasis on an even and axial force distribution throughout the dentition. Adjustable composites and temporary restorations were used to establish a favorable occlusal scheme before moving on to permanent restorations.

A novel wear prediction method and wear characteristic analysis of piston/cylinder pair in axial piston pump

The wear of the piston/cylinder pair in the axial piston pump is a significant factor that adversely affects pump performance. To conduct a thorough investigation into the wear characteristics of the piston/cylinder pair, a dynamic model based on the equivalent load method is established. Then, a novel wear prediction method for the piston/cylinder pair is proposed by integrating the Archard wear model. The validity of the proposed method is confirmed through experimental verification. The results demonstrate that specific circumferential areas of the cylinder bore exhibit severe wear, and the distribution of these areas remains relatively stable over time. At the swash plate side, the most severe wear area along the circumference direction is concentrated in the range of approximately 200°–320°, which means the area that deviates from the extreme position in the radial direction of the pitch circle by a specific angle, with the deviation direction being opposite to the rotational speed. Conversely, at the valve plate side, the most severely worn circumferential area is situated in the range of about 0°–120°, which is opposite to the area at the swash plate side. The proposed wear prediction method offers improved computational efficiency, providing valuable support for analyzing the wear characteristics and failure mechanisms of piston pumps.

Dental and Implantoprosthetic Rehabilitation of the Vertical Dimension in an Elderly Patient with Severe Parafunction

Tooth wear can have several etiological factors. When they occur in combination, the clinical result can be quite devastating, with severe tooth destruction. The purpose of this article is to present the case of a elderly patient with severe tooth wear caused by parafunctional habits (bruxism), with a marked reduction in the vertical dimension of the lower third of the face. Dental and implantoprosthetic rehabilitation was carried out, restoring the vertical dimension.

Piston ring and cylinder liner scuffing analysis in dual-fuel low-speed engines considering liner deformation and tribofilm evolution

The piston ring and cylinder liner (PRCL) system in larger-bore low-speed marine engines frequently experiences scuffing failures, which significantly decrease the engine reliability. To understand this failure mechanism, a scuffing failure model subjected to the PRCL system was developed considering multidisciplinary coupling effects that integrate asperity contact, hydrodynamic lubrication, tribochemistry reactions, thermal effects, friction, and surface wear. The impacts of large-scale deformation and gas-combustion mode on the scuffing performances of the PRCL system were examined. The key findings indicate that the larger-scale liner deformation can markedly reduce oil film thickness and exacerbate local asperity contact, influencing the evolution of the tribofilm by increasing the removal process. Under gas-combustion mode, the oil film thickness is even lower, and the asperity contact pressure further increases due to a more starved lubrication state and higher combustion temperature. This leads to tribofilm breakdown and severe wear near the ring opening area, which are aligning with the full-scale experimental results with scuffing failure.