Search Results (33)

Aluminum conductor cables are exposed to environmental conditions in service, where wind-induced vibrations generate multiaxial stresses and cause partial sliding between the stranded layers. Such dynamic loading can lead to fatigue or wear failure, particularly at the contact zones between wire layers. The influence of heat treatment and cold work on the wear of these aluminum wires remains unstudied. This work aims to evaluate the microabrasive wear of rolled and heat-treated 6201 aluminum alloy wires used in conductor cables. The wear tests were performed using free-ball microabrasive wear equipment and alumina (Al₂O₃) abrasive paste at a concentration of 0.40 g/mL of distilled water. The parameters used were as follows: 100 Cr6 steel balls with a diameter of 25.4 mm, sample inclination of 60°, normal force of 0.3 N, and shaft speed of 0.185 m/s or 280 rpm. The test time was set at 20 min, 30 min, 40 min, 50 min, and 60 min. The wear test data were processed using the Achard equation. The microabrasive wear test results indicate that the wear coefficient decreased by 19.1% after the artificial aging process, compared with the solution-treated alloy (95% CI: 15.5–22.3%), and this reduction was statistically significant (p < 0.001). After the combined treatment of rolling and artificial aging, the alloy had a drop in wear coefficient of 36.1% compared to the same solution-treated alloy (95% CI: 32.6–39.6%), representing the largest statistically significant improvement among the tested conditions (p < 0.001). Cold work (rolling) reduces the mobility of dislocations, requiring greater stress to deform the material, thereby increasing its stiffness and wear resistance. In this 6201 alloy, it is inferred that artificial aging led to the formation of Guinier-Preston zones, which evolved into the formation of metastable β” precipitates in needle-like form, coherent with the matrix. As the aging process progresses, the β’ particles evolve into larger β particles that are no longer coherent with the matrix. The combined processes of rolling and aging decrease the wear coefficient. Statistical analysis demonstrated that microstructural conditions explain approximately half of the total variability in the wear coefficient (η² = 0.495), indicating that the wear performance under the present experimental configuration is primarily governed by intrinsic strengthening mechanisms rather than experimental variability. Full article

This study systematically investigates the influence of short carbon-fiber (SCF) content on the mechanical, thermal, and tribological properties of self-lubricating polyphenylene sulfide (PPS) composites filled with PTFE and MoS2, addressing the critical need for high-wear resistance in Carbon-Fiber-Reinforced Thermoplastic (CFRTP) structural applications. The results identified 10 wt% SCF as the optimal content that achieved the best balance between load-bearing capacity and friction performance. The coefficient of friction μ and wear amount were reduced by 29.28% and 29.29%, respectively, compared to the PPS/PTFE/MoS2 composite material without SCF, and by 14.67% and 20.75%, respectively, compared to the material with excessive SCF filling (20 wt%). Finite-Element Analysis-Representative Volume Element (FEA-RVE) reveals the mechanism by which excessive content of SCF at the microscopic level leads to a slight decrease in mechanical properties. Critically, the tribological performance exhibited a discrepancy with bulk mechanical properties: above 15 wt% SCF, the wear rate worsened despite high mechanical strength, revealing that increased fiber agglomeration and micro-abrasion effects were the primary causes of performance deterioration. Further in-depth XPS analysis revealed a synergistic lubrication mechanism: In the optimal sample, an ultra-dense PTFE transfer film was formed to mask the underlying MoS2. This masking, coupled with the high surface activity of MoO3 particles leads to stronger physicochemical interactions with the polymer matrix, ensures the exceptional durability and stability of the tribo-film. This research establishes a complete structure–performance relationship by integrating mechanical, thermal, and tribo–chemical mechanisms, offering critical theoretical guidance for the design of next-generation high-performance self-lubricating CFRTPs. Full article

Enhancing the local mechanical response of low-carbon cast steels remains essential for improving their performance in wear-intensive environments. In this work, a low-carbon cast steel was locally modified through the in situ formation of TiC particles via melt reaction with pressed Ti–Al–C powders. Advanced microstructural characterization (SEM/EDS, EBSD, and TEM) revealed a heterogeneous TiC-reinforced composite microstructure containing ~36 vol.% TiC with particle sizes between 0.73 and 3.88 μm. The reinforced region exhibited a substantial increase in hardness, from 160 ± 5 HV30 in the base steel to 407 ± 78 HV30, resulting from the synergistic contribution of TiC particles, fine κ-carbides, and a martensitic matrix. Nanoindentation revealed a strong mechanical contrast between phases, with TiC achieving 25.70 ± 7.76 GPa compared to 4.68 ± 1.09 GPa for the base metal matrix. Micro-abrasion tests showed a 24% reduction in wear rate, accompanied by shallower grooves and reduced plastic deformation. These findings demonstrate that in situ TiC formation, combined with κ-carbide precipitation, provides an effective strategy for improving local hardness and abrasive wear resistance in low-carbon cast steels. The results highlight the potential of in situ composite formation as an effective microstructural engineering strategy for next-generation wear-resistant cast steels. Full article

This study presents an effective route for producing functionally graded metal matrix composites with enhanced abrasion wear resistance by incorporating ex situ Fe–WC preforms into austenitic stainless-steel castings. The preforms, produced by cold-pressing mixed WC and Fe powders, were positioned in the desired locations in sand molds and reacted in situ with the molten steel during casting. This process generated a metallurgically bonded reinforcement zone with a continuous microstructural and compositional gradient, characteristic of a Functionally Graded Material (FGM). Near the surface, the microstructure consisted of a martensitic matrix with WC particles and (W,Fe,Cr)₆C carbides, while towards the base metal, it transitioned to austenitic dendrites with an interdendritic network of Cr- and W-rich carbides, including (W,Fe,Cr)₆C, (Fe,Cr,W)₇C₃, and (Fe,Cr,W)₂₃C₆. Vickers hardness measurements revealed surface-adjacent values (969 ± 72 HV 30) approximately six times higher than those of the base alloy, and micro-abrasion tests demonstrated a 70% reduction in micro-abrasion wear rate in the reinforced zones. These findings show that WC dissolution during casting enables tailored hardness and abrasion wear performance, offering an accessible manufacturing solution for high-demand mechanical environments. Full article

This article presents the wear characteristics of the working surface of WC-Co (Tungsten Carbide–Cobalt) tungsten carbide tools obtained using the innovative U-FAST (Upgraded Field-Assisted Sintering Technology) method for particleboard machining. Three groups of tools with a similar chemical composition but differing WC (Tungsten Carbide) grain sizes were tested. Milling tests were carried out on a CNC (Computer Numerical Control) machine tool with the following cutting parameters: spindle rotation at 15,000 rpm, a feed rate of 0.25 mm per tooth, and a feed rate of 3.75. The experimental results show that tools with submicron WC grit sizes of 0.4 µm and 0.8 µm have the longest tool life. Wear of the cutting edges occurred through the removal of the cobalt bond between the tungsten carbide grains, leading to fracture and mechanical removal of the grains from the cutting edge surface. The similarities in the relative wear characteristics of blades with submicron tungsten carbide grain sizes suggest that micro-abrasion and bond phase extrusion may be the main wear mechanisms under the experimental conditions. Nanometric WC grain size significantly influences tool wear through chipping and cracking. Full article

Nowadays, high requirements imposed by mechanical components make it necessary to develop modern production methods. Additive technologies have been dynamically developing in recent years, showing many advantages associated with the fabrication of elements with complex geometries and structures. One of the areas where the potential of additive technologies is exploited is the rapid tooling sector, which is based on the rapid production of tools and components used in various manufacturing methods. Currently, apart from industrial additive fabrication using metal and plastic powders, desktop and low-cost devices for additive manufacturing are gaining more and more importance in the production of functional elements. This paper presents the experimental results obtained from testing the micro-abrasive acrylonitrile–butadiene–styrene ABS tools fabricated by fused filament fabrication (FFF) technology and reinforced with SD 28/20 diamond grains uniformly distributed on the working surface of the tools after they were made. Precision surface grinding operations of 41Cr4 alloy steel were carried out on a portable five-axis CNC milling machine using wheels with continuous and serrated working surfaces. The tool with a serrated working surface enabled a more efficient material removal and produced a better surface finish. In particular, a low wear rate of both FFF-printed tools was confirmed after all experiments. Promising results were obtained, showing the potential for a wider industrial application of the tested tools. Full article

Most of the biomass of cereal straw is chopped and left on the field as organic fertilizer, but its conversion into fertilizer depends on the quality of chopping, which is influenced by the wear of the chopping blades. The aim of the study was to determine the influence of the contamination of the cereal straw on the wear of the combine chopper blades. The study was conducted during the harvest in 2022, when 30 ± 1% of the grain was lodged and contaminated with abrasive soil particles (poor conditions), and in 2023, when the straw was unlodged and clean (excellent conditions). Six sets of blades with different mechanical and geometric properties were selected. The results showed that the wear ranges were very different: 1.47–2.99 g/100 ha in 2022 and 0.72–2.14 g/100 ha in 2023. For micro-abrasive wear, the hardness of the blades (349–568 HV) and the cutting edge angle (20°–29°) were important factors of their wear resistance. When the clean straw was chopped, the influence of the blade hardness and cutting edge angle on wear was not significant, and the wear was less. The wear of the blades had a sinusoidal character, which was related to the position of the blades on the chopping drum. This character depends on the design of the chopper and not on the straw quality. Full article

Titanium alloys have a high cost of production and exhibit low resistance to abrasive wear. The objective of this work was to carry out diamond-like carbon (DLC) coating, with dissimilar thicknesses, on Ti-22Nb-6Zr titanium alloys produced by powder metallurgy, and to evaluate its microabrasive wear resistance. The samples were compacted, cold pressed, and sintered, producing substrates for coating. The DLC coatings were carried out by PECVD (plasma-enhanced chemical vapor deposition). Free sphere microabrasive wear tests were performed using alumina (Al₂O₃) abrasive suspension. The DLC-coated samples were characterized by scanning electron microscopy (SEM), Vickers microhardness, coatings adhesion tests, confocal laser microscopy, atomic force microscopy (AFM), and Raman spectroscopy. The coatings did not show peeling-off or delamination in adhesion tests. The PECVD deposition was effective, producing sp2 and sp3 mixed carbon compounds characteristic of diamond-like carbon. The coatings provided good structural quality, homogeneity in surface roughness, excellent coating-to-substrate adhesion, and good tribological performance in microabrasive wear tests. The low wear coefficients obtained in this work demonstrate the excellent potential of DLC coatings to improve the tribological behavior of biocompatible titanium alloy parts (Ti-22Nb-6Zr) produced with a low modulus of elasticity (closer to the bone) and with near net shape, given by powder metallurgy processing. Full article

Sanding in medium-density fiberboard (MDF) often encounters unstable quality and premature failure, primarily because there is currently no abrasive belt specifically suitable for MDF sanding characteristics. We designed two precision-shaped abrasive belts (PSAs) for MDF and herein report on the characteristics. The material removal process for PSA was divided into three phases; the most stable, phase II, represents the effective working period. Compared to the contrast accumulated abrasive belt, PSAs achieve 16.12 and 11.10 times higher surface quality based on the mean value of roughness parameter S_a, achieving 1.34- and 2.0-, and 15.61- and 8.54-times-higher stability in material removal and surface quality based on the mean deviation. Wear patterns on PSAs include large abrasive wear, micro-abrasive fall-off, fracture, and wear, avoiding premature failure due to blockage and promoting long-term and efficient sanding. The uniform shape, height, and distribution of particles in PSAs results in excellent sanding performance. This study provides the foundation for further research on sanding mechanisms and PSA design for MDF. Full article

Martensitic low-alloy steels are widely used in machine construction. Due to their declared weldability, arc welding is most often used to join elements made of this type of steel. However, the high temperature associated with welding causes unfavourable changes in the microstructure, resulting in reduced abrasion resistance. Therefore, it is important to know the tribological properties of the welded joint. This article presents the results of a study on the abrasion wear resistance of a welded joint of an abrasion-resistant steel. This study tested a welded joint of an abrasive-resistant steel produced by the arc welding method. Wear testing of the welded joint was carried out under laboratory conditions by the ball-cratering method in the presence of abrasive slurry on the cross-section of the welded joint. Based on the test results, the change in the abrasive wear rate of the material as a function of the distance from the welded joint axis was determined. It was also found that the thermal processes accompanying welding caused structural changes that increased the wear rate index value. Adverse changes in the tribological properties of a welded material persist up to a distance of approx. 20 mm from the weld centre. Full article

In micro-abrasive water jet polishing (MAWJP) technology, where abrasive particles serve as polishing tools, particles tend to form large clusters, leading to increased nozzle wear and diminished material polishing quality. Achieving a polishing solution with good dispersion stability is crucial for enhancing polishing accuracy and minimizing nozzle wear. Therefore, this study employed three dispersants with distinct dispersion mechanisms to examine the impact of each dispersant’s concentration on the dispersion stability of the polishing solution across various abrasive concentrations. Through experimentation, the optimal dispersant type and concentration ratio of abrasive to dispersant were determined, and the effect of the selected dispersant on jet polishing performance was validated. The results of the dispersion stability experiment indicated that, in comparison to Na(PO₃)₆ and polyethylene glycol (PEG), the polishing solution containing 1.0–2.0 wt% phosphoric ester compounds exhibited a more stable dispersion effect (zeta potential < −50 mV) and superior dispersibility, characterized by a smaller average particle size. Furthermore, K9 optical glass was subjected to fixed-point and local polishing using phosphoric ester compounds as the dispersant. The fixed-point polishing experiment revealed that, at a dispersant concentration of 1.0 wt% and an abrasive concentration of 20 wt%, a smooth and symmetrical material removal profile could be achieved. In the local polishing experiment, the reduction rate of the root mean square of the surface roughness (RMS) increased from 54.33% to 82.24%, and the reduction rate of peak-to-valley height difference in surface (PV) increased from 38.84% to 68.97%. In conclusion, the incorporation of a dispersant proves effective in enhancing the dispersion stability of the polishing solution and dispersibility of the abrasive particles, thereby improving the surface quality of the materials in MAWJP. Full article

The paper investigates the effects of DC plasma nitriding on surface roughness, hardness, microstructure, micro-abrasion, and corrosion resistance of AISI 316L Austenitic Stainless (AS) steel. The nitriding has been conducted for durations ranging from 4 to 24 h at a temperature of 430 °C in a commercial vacuum furnace, Rübig PN90/70. Micro-abrasion resistance has been tested using the calotest device with a measurement diameter of craters produced on the sample surface after 10 to 60 s of wear. Corrosion resistance has been tested using the Electroimpedance Spectroscopy (EIS) method in a 3.5% NaCl water solution. The surface roughness parameters and hardness of the samples increased with longer nitriding times, attributed to the saturation of austenite and the formation of iron and chromium nitrides. Nitriding for longer than 8 h resulted in the formation of a thicker compound layer that is hard and brittle, leading to reduced wear resistance compared with shorter nitriding times. EIS measurements revealed that nitrided samples had lower corrosion resistance compared with the untreated sample. The corrosion stability was not significantly affected by nitriding time. Different nitriding times have a great influence on resistance to pitting corrosion. This study provides valuable insights into the effects of plasma nitriding on the properties of AS steel, highlighting the importance of optimizing nitriding parameters for specific applications. Full article

Background: A novel, lumbar total joint replacement (TJR) design has been developed to treat degeneration across all three columns of the lumbar spine (anterior, middle, and posterior columns). Thus far, there has been no in vitro studies that establish the preclinical safety profile of the vitamin E-stabilized highly crosslinked polyethylene (VE-HXLPE) lumbar TJR relative to historical lumbar anterior disc replacement for the known risks of wear and impingement faced by all motion preserving designs for the lumbar spine. Questions/Purpose: In this study we asked, (1) what is the wear performance of the VE-HXLPE lumbar TJR under ideal, clean conditions? (2) Is the wear performance of VE-HXLPE in lumbar TJR sensitive to more aggressive, abrasive conditions? (3) How does the VE-HXLPE lumbar TJR perform under impingement conditions? Method: A lumbar TJR with bilateral VE-HXLPE superior bearings and CoCr inferior bearings was evaluated under clean, impingement, and abrasive conditions. Clean and abrasive testing were guided by ISO 18192-1 and impingement was assessed as per ASTM F3295. For abrasive testing, CoCr components were scratched to simulate in vivo abrasion. The devices were tested for 10 million cycles (MC) under clean conditions, 5 MC under abrasion, and 1 MC under impingement. Result: Wear rates under clean and abrasive conditions were 1.2 ± 0.5 and 1.1 ± 0.6 mg/MC, respectively. The VE-HXLPE components demonstrated evidence of burnishing and multidirectional microscratching consistent with microabrasive conditions with the cobalt chromium spherical counterfaces. Under impingement, the wear rates ranged between 1.7 ± 1.1 (smallest size) and 3.9 ± 1.1 mg/MC (largest size). No functional or mechanical failure was observed across any of the wear modes. Conclusions: Overall, we found that that a VE-HXLPE-on-CoCr lumbar total joint replacement design met or exceeded the benchmarks established by traditional anterior disc replacements, with wear rates previously reported in the literature ranging between 1 and 15 mg/MC. Clinical Relevance: The potential clinical benefits of this novel TJR design, which avoids long-term facet complications through facet removal with a posterior approach, were found to be balanced by the in vitro tribological performance of the VE-HXLPE bearings. Our encouraging in vitro findings have supported initiating an FDA-regulated clinical trial for the design which is currently under way. Full article

Nowadays, due to the carcinogenic effects of chrome, replacing the hard chromium used for hydraulic components like rods and cylinders is becoming increasingly requested. Thermally sprayed coatings are a solution to the problem; however, proper understanding and characterisation of their tribological behaviour are essential for the successful exploitation of surface engineering. Thus, the main aim of this study is to evaluate the abrasive wear characteristics of two metal sprayed layers, tungsten carbide (WC) deposited through the high-velocity oxygen fuel coating (HVOF) method and Fe alloy coating deposited through thermal spraying with an electric arc with a wire-electrode G3Si1, and compare the results with those of an electrochemically deposited hard chromium layer. Their wear resistance is then related to their hardness. The results highlight the tribological performances of the thermally sprayed coatings. The HVOF WC10Co4Cr coating has a wear coefficient and a material wear volume that are hundreds of times lower than those of the other two coatings. Full article

Cereal straw is a biomaterial with great potential: about 144 million tons of biomass are grown annually in Europe. For any use of straw (fertilizer, biofuel, etc.), efficient chopping technology, i.e., the reliable and efficient operation of mobile or stationary choppers, is the key factor for further success. Since most of the straw is chopped at harvest time, the subject of the study is the wear of the combine’s chopping knives. Six blades of different materials and designs were tested under realistic conditions during wheat and rapeseed harvesting on 180 ha. The influence of hardness, composition, cutting edge angle, and position in the chopper on knife wear was analyzed. The study showed that the blades with the highest cutting edge hardness (568 ± 11 HV) and the lowest cutting edge angle (20.9°) had the lowest wear. The highest hardness of the induction hardened knives was due to the 0.42% carbon content of the steel. The study confirmed that wear was inversely proportional to the hardness of the cutting edge (the harder the cutting edge, the lower the wear) and directly proportional to the angle of the cutting edge (the higher the angle, the greater the wear). The SEM study showed that part of the tooth surface of the blades was covered by permanent deposits of the material to be shredded. This wear was not caused by the interaction between straw and blade but by microabrasive particles that contaminated the straw. Full article