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Polymer additive manufacturing has advanced from prototyping to producing essential parts with improved precision and versatility. Despite challenges like surface finish and wear resistance, new materials and metallic reinforcements in polymers have expanded its applications, enabling stronger, more durable parts for demanding industries like aerospace and structural engineering. This research investigates the tribological behaviour of FFF surfaces by integrating copper and aluminium reinforcement particles into a PLA (polylactic acid) matrix. Pin-on-disc tests were conducted to evaluate friction coefficients and wear rates. Statistical analysis was performed to study the correlation of the main process variables. The results confirmed that reinforced materials offer interesting characteristics despite their complex use, with the roughness of the fabricated parts increasing by more than 300%. This leads to an increase in the coefficient of friction, which is related to the variation in the material's mechanical properties, as the hardness increases by more than 75% for materials reinforced with Al. Despite this, their performance is more stable, and the volume of material lost due to wear is reduced by half. These results highlight the potential of reinforced polymers to improve the performance and durability of components manufactured through additive processes.
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Flexible protective armors are found in large animals such as fish skins, snake skins, and pangolin scales. For small-sized invertebrates, such armors are paid less attention and overlooked. Chitons, a type of marine mollusk, possess mineralized armors covering the whole dorsal body. The dorsal scales in the girdle tissue are well known, in this study, we reported hidden mineralized scales in the ventral side of chiton Acanthopleura loochooana girdles for the first time. The ventral surface is covered with scales with ca. 40 µm in length, forming continuous but overlapped scales. Additionally, scales are formed from aragonitic spicule-like and square-like scales, embedded in the cuticle layer. Nanoindentation testing results showed that the hardness and elastic modulus of ventral scales were â¼20 % higher compared to those in the dorsal scales, exhibiting good hardness and wear resistance. The combination of the ventral scales and cuticle, along with the regular arrangement of ventral scales, may allow chitons to simultaneously address complex and variable attachment interfaces while also providing wear-resistant protection. This study provides insights for designing protective structures that balance flexibility and durability. STATEMENT OF SIGNIFICANCE: Biomineralization is universal in nature and provides protection and support for animals. However, mineralization of dermal skin is not commonly seen. Herein, for the first time, we reported hidden minerals covering the whole ventral side of skin in a small marine animal, chitons. Calcium carbonate minerals are arranged regularly and manifest different morphology in different regions. Additionally, these minerals are embedded in a continuous cuticle layer covering the whole animal. The material also indicates a higher wear-resistant property. This study extends our understanding of the diverse functionality of biominerals and provides a prototype for designing wear-resistant materials.
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PURPOSE: While additive manufacturing (3D printing) has recently enhanced removable prosthodontics, the properties of new 3D printed materials are not well understood. This study aims to elucidate the physical properties of these materials, focusing on bonding to a 3D printed denture base material and wear resistance. METHODS: For denture tooth-denture base bonding analyses, the same denture tooth material (Premium Teeth, Formlabs) was used with three denture base-bonding group assignments (n=6 each group) bonded using three protocols: Group A1 was bonded with Lucitone Digital Print-3D Denture Base using the Lucitone Fuse System (Dentsply), Group A2 with Formlabs Denture Base using the Formlabs Denture Base Bonding System, and Group A3 with Formlabs Denture Base using the Ivoclar Ivotion Bonding System (Ivoclar). Specimens were made according to the ISO-TS-19736-2027 standard. A 3D printed tooth mimicking a central incisor was bonded to the denture base and subjected to a palatal load at the incisal region at 90° from the long axis of the tooth until failure. The fracture surface was examined at 10× magnification. ANOVA with α=0.05 was used to determine statistically significant differences. For wear analysis, the same denture base material and bonding system (Lucitone Digital Print-3D Denture Base/Lucitone Fuse System, Dentsply) was used with four denture tooth material group assignments (n=8 each group): Group B1 used Formlabs Premium Teeth, Group B2 used SprintRay High Impact Denture Teeth, Group B3 used Lucitone Digital IPN Premium Tooth, and Group B4 used Ivotion Polymethyl Methacrylate (PMMA) Milled Teeth (Ivoclar). A premolar denture tooth bonded with the denture base was subjected to a chewing simulation cyclic loading of 1,200,000 cycles. Sample failures, vertical wear, and volume loss were documented. ANOVA with α=0.05 was used to determine statistically significant differences. RESULTS: The fracture load to failure values for A1, A2, and A3 were 175±106 N, 167±46.3 N, and 183±48.9 N, respectively (p=0.95). Most failure characteristics were mixed, except one of A2 was cohesive and half of A3 was cohesive. For cyclic loading, B4 was the only group where all specimens failed within 1,200,000 cycles, while B1, B2, and B3 had four, three, and five sample failures, respectively. Vertical wear was 0.93±0.34 mm, 1.22±0.37 mm, 1.05±0.27 mm, and 0.37±0.02 mm for B1, B2, B3, and B4, respectively (p<0.01). Abrasion volumes were 9.5±3.7 mm³, 12.2±4.7 mm³, 10.6±3.5 mm³, and 2.2±1.3 mm³ for B1, B2, B3, and B4, respectively. Vertical height loss per chewing cycle (µm/cycle) was 0.0022±0.0019, 0.0030±0.0029, 0.0012±0.00005, and 0.0080±0.0050 for B1, B2, B3, and B4, respectively (p<0.01). Abrasion volume per chewing cycle (µm³/cycle) was 17650.8±9682.9, 27263.4±24746.8, 11836.5±4200.8, and 70436.8±73602.5 for B1, B2, B3, and B4, respectively (p=0.02). CONCLUSION: The bonding strength and wear resistance of 3D printed denture materials vary by manufacturer. Formlabs Denture Base with Ivoclar Ivotion showed the highest fracture load, indicating superior bonding strength. In wear analysis, Ivoclar Ivotion PMMA Milled Teeth exhibited the least vertical wear and abrasion volume but had the highest failure rate under cyclic loading. While printed denture materials excel in bonding strength, their wear resistance may not be as good as milled denture teeth, highlighting the need to balance these properties in clinical applications.
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BACKGROUND: Skin flap transplantation is used to effectively reconstruct defects of the hand and foot skin and soft tissues. We here investigated the effect of the PF127/bleomycin (BLM) hydrogel on the extracellular matrix (ECM) remodeling of skin flaps and the underlying mechanism, thereby providing a new reference point for personalized flap modification and overcoming abrasion resistance- and stability-associated difficulties. METHODS: The appropriate PF127/BLM concentration was selected based on the gelation time and drug release curve. Migration assays, scratch assays, and live/dead staining were conducted to verify the effect of PF127/BLM on human skin fibroblasts (HSFs). The effects of PF127/BLM on the ECM were assessed through hematoxylin and eosin and Masson staining. Additionally, we examined the expression of ECM remodeling-related genes and proteins involved in their associated signaling pathway. Finally, the effects of PF127/BLM on organ fibrosis and toxicity to liver and kidney functions were assessed in mice. RESULTS: A 25% PF127/BLM hydrogel was selected as the study concentration. PF127/BLM augmented HSF chemotaxis and proliferation. Furthermore, PF127/BLM promoted subcutaneous ECM remodeling and fibrosis, increased the flap dermis thickness, and reduced the toxic side effects of BLM on liver/lung fibrosis and liver/kidney function. Additional studies confirmed that the PF127/BLM-mediated regulation of ECM remodeling in skin flaps was associated with TGFß-Col signaling pathway activation. CONCLUSION: The PF127/BLM hydrogel promoted subcutaneous ECM remodeling and fibrosis, which aided the construction of personalized flaps through the TGFß-Col signaling pathway, with decreased hepatic, pulmonary, and renal toxicities.
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In this paper, enhancing the tribological characteristics of novel cast metallic materials-hybrid multi-component cast irons-by applying a strengthening heat treatment is described. The experimental materials were the cast alloys of a nominal composition (5 wt.% W, 5 wt.% Mo, 5 wt.% V, 10 wt.% Cr, 2.5 wt.% Ti, Fe is a balance) supplemented with 0.3-1.1 wt.% C and 1.5-2.5 wt.% B (total of nine alloys). The heat treatment was oil-quenching followed by 200 °C tempering. The quench temperature (QT) varied in the range of 900-1200 °C, with a step of 50 °C (with a 2-h holding at QT). The correlation of the QT with microstructure and properties was estimated using microstructure/worn surface characterization, differential scanning calorimetry, hardness measurement, and three-body-abrasive wear testing (using Al2O3 particles). The as-cast alloys had a multi-phase structure consisting of primary and/or eutectic borocarbide M2(B,C)5, carboborides M(C,B), M7(C,B)3, M3(C,B), and the matrix (ferrite, martensite, pearlite/bainite) in different combinations and volume fractions. Generally, the increase in the quenching temperature resulted in a gradual increase in hardness (maximally to 66-67 HRC) and a decrease in the wear rate in most alloys. This was due to the change in the phase-structure state of the alloys under quenching, namely, the secondary carboboride precipitation, and replacing ferrite and pearlite/bainite with martensite. The wear rate was found to be inversely proportional to bulk hardness. The maximum wear resistance was attributed to QT = 1150-1200 °C, when the wear rate of the alloys was lowered by three to six times as compared to the as-cast state. With the QT increase, the difference in the wear rate of the alloys decreased by three times. The highest abrasive resistance was attributed to the alloys with 1.1 wt.% C, which had a 2.36-3.20 times lower wear rate as compared with that of the reference alloy (13 wt.% Cr cast iron, hardness of 66 HRC). The effects of carbon and boron on hardness and wear behavior are analyzed using the regression models developed according to the factorial design procedure. The wear mechanisms are discussed based on worn surface characterization.
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High entropy alloys have excellent wear resistance, so they have great application prospects in the fields of wear resistance and surface protection. In this study, the wear resistance of the FeNiCrCoCu high entropy alloy coating was systematically analyzed by the molecular dynamics method. FeNiCrCoCu high entropy alloy was used as a coating material to adhere to the surface of a Cu matrix. The friction and nanoindentation simulation of this coating material were carried out by controlling the ambient temperature. The influence of temperature on its friction properties was analyzed on five aspects: lattice structure, dislocation evolution, friction coefficient, hardness, and elastic modulus. The results show that with the increase of temperature, the disorder of the lattice structure increases, which leads to an increase of the tangential force and friction coefficient in the friction process. At 300 K and 600 K, the ordered lattice structure of the high entropy alloy coating material is basically the same, and thus its hardness is basically the same. However, the dislocation density at 600 K is significantly reduced compared with that at 300 K, resulting in an increase of the elastic modulus of the material from 173 GPa to 219 GPa. At temperatures of 900 K and 1200 K, lattice disorder takes place rapidly, and dislocation density also decreases significantly, resulting in a significant decrease in the hardness and elastic modulus of the material. When the temperature reaches 900 K, the wear resistance of the FeNiCrCoCu high entropy alloy coating decreases sharply. This work is of great value in the analysis of wear resistance of high entropy alloys at high temperature.
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Commercially pure titanium was plasma paste borided using various temperatures of the process. An increase in the boriding temperature resulted in an increase in the thickness of the borided layer. All the layers produced consisted of an outer compact TiB2 zone and an inner TiB zone in the form of whiskers penetrating into the substrate. The presence of hard titanium borides resulted in a significant increase in wear resistance compared to non-borided pure titanium. However, the thickness of the layer produced strongly influenced the wear behavior, in respect of the time required for complete destruction of the layer. Higher wear resistance was characteristic of the TiB2 layer due to its compact nature, whereas the specific morphology of TiB whiskers resulted in their lower wear resistance compared to the outer TiB2 layer. Plasma paste boriding of pure titanium also had an advantageous effect on corrosion resistance compared to non-borided pure titanium. Simultaneously, due to the higher thickness of TiB2 layer, the specimen borided at a higher temperature showed higher corrosion resistance.
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Aluminium finds wide application in mechanical engineering due to its low density and corrosion resistance. In this research, aluminium was subjected to two different metal forming technologies-cold forging (upsetting) and equal channel angular pressing (ECAP)-to obtain improvement in its exploitation properties. Parallel to changing mechanical properties by using these two processes, there was a change in the microstructure of the material. The resulting microstructures were examined using an optical microscope. A different treated aluminium was subjected to erosion wear in various time intervals. Wear testing was conducted for two different impingement angles causing abrasive wear and impact wear. The erosion mechanisms were examined by scanning electron microscopy. These results showed that there is no statistically significant difference in erosion wear for different states at the same impingement angle. However, the difference is noticeable at different wear angles. The significance of the difference in wear of the samples treated with the forging and ECAP techniques was validated by statistical analysis with tests of different sensitivities. The results of the t-test showed that ECAPed samples present a statistically significant difference in the loss of mass due to variations in erosion angle during the 30, 45, and 60 min wearing. A substantial difference in the change in sample mass is also visible for the forged state worn for 60 min.
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Polyoxymethylene (POM), an engineering polymer commonly used in tribological applications, is often reinforced with fossil-based fibers such as carbon and/or glass fibers to improve its properties. To find more sustainable solutions, in this study, the tribological performance of POM/short cellulose fiber composites at different sliding conditions is investigated. An improvement in the wear coefficient of roughly 69% is observed at the harshest conditions of 5 MPa and 1 m · s-1 with only 10 wt.% cellulose fibers. The friction behavior is furthermore stabilized through fiber addition, as the unfilled polymer did not show a steady state. No signs of thermo-oxidative degradation are found after tribological testing. This study presents promising results for sustainable wear-resistant polymer materials in tribological applications.
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PURPOSE: The purpose of this study was to compare the wear, fracture strength, and mode of failure of various brands of 3D-printed resin denture teeth with prefabricated acrylic resin. Additionally, the study aimed to analyze the different modes of failure exhibited by these teeth. MATERIALS AND METHODS: The study utilized 90 3D-printed and 30 prefabricated, 3D-printed resin teeth from three brands: L = Optiprint Lumina, A = ASIGA DentaTooth, P = Power resins, along with prefabricated acrylic teeth from M = Major Super Lux. Each of the 30 samples per main group was divided into two subgroups: The first subgroup samples (M1, A1, L1, P1) were subjected to thermal cycling and mechanical loading; M2, A2, L2, and P2 were not aged and tested directly. A scan of a prefabricated acrylic tooth was taken using an intraoral scanner, and then the STL file was printed using an Asiga 3Dprinter. The specimens underwent aging to simulate 5 years of clinical use with 10,000 thermal cycles and 1,200,000 dynamic load cycles on a chewing simulator. Surface roughness parameters (Rz, Ra, Rq) were measured using a 3D Optical Profilometer, fracture resistance was assessed using a universal testing machine, and SEM analysis was performed to observe failure modes. Statistical analysis using T-test, one-way analysis, and two-way analysis processed by the Statistical Package for Social Sciences (SPSS) software version 23.0 (SPSS: Inc., Chicago, IL, USA) was done with a level of significance set at <0.05. RESULTS: The results showed that the difference in surface roughness parameters (Rz, Ra, Rq) before and after aging for Group M, Group A, Group L, and Group P was statistically significant (p < 0.05). Two-way ANOVA for wear resistance between aging and groups on dependent variable Rz (p = 0.002), Ra (p = 0.001), Rq (p = 0.001) were significant. Multiple comparisons for surface roughness parameters showed Group A and Group L were lower than Group P and Group M (p < 0.05). For fracture strength, One-way ANOVA showed a significant difference between groups for fracture strength either without or after the aging procedure (p < 0.05). Multiple comparisons for fracture strength without aging showed no significant difference between Group M, Group A, and Group L (p > 0.05). After the aging procedure fracture strength for Group M was higher than Group A, Group L, and Group P (p < 0.05). CONCLUSION: 3D-printed resin teeth showed a greater and comparable wear resistance to prefabricated acrylic teeth. Fracture strength was comparable between prefabricated acrylic teeth and 3D-printed resin (Asiga and Lumina) before aging, but after aging 3D-printed resin teeth showed less fracture strength.
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PURPOSE: This in vitro study investigated the effect of build orientation on the wear resistance and hardness of denture teeth fabricated using digital light processing (DLP) compared to other denture tooth materials. METHODS: Disc-shaped specimens were prepared using denture tooth monomers and DLP devices in three build orientations: 0°, 45°, and 90°. Specimens of the same shape were fabricated using denture tooth materials for subtractive manufacturing, commercially available polymethylmethacrylate (PMMA) resin, and composite resin. The wear resistance was evaluated as the wear volume loss after 50,000 wear cycles using a ball-on-disc wear device in water for two-body wear and poppy seed slurry for three-body wear. The Vickers hardness values of the materials were measured. Two-way and one-way analyses of variance were performed for wear resistance and hardness, respectively, followed by Tukey's honest significance test. RESULTS: The interaction between the denture tooth resins and maximum wear volume was significant (P < 0.01). The 0° build orientation exhibited the lowest wear volume in the three-body wear test and the highest hardness among the three build orientations. The 0° DLP-fabricated specimens demonstrated significantly less wear volume than that of the PMMA specimens and a wear volume comparable to that of the milled specimens. However, the 0° DLP-fabricated specimens showed significantly lower hardness than that of the milled and PMMA specimens. The composite resin specimens exhibited the highest wear resistance and hardness. CONCLUSIONS: A 0° build orientation is recommended for DLP-fabricated denture teeth compared to 45° and 90° orientations to achieve greater wear resistance and hardness.
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It is known that Copper's (Cu) electrical conductivity makes it a desirable material for use in industry. Due to poor properties such as hardness, thermal expansion, and corrosion resistance, its applications are limited. This manuscript solves these problems while maintaining no breakdown in electrical conductivity. In this study, high-strength ceramics (SiC nanoparticles and graphene nanosheets) were used as reinforcements in the manufacture of Cu-based hybrid nanocomposites using powder metallurgy technique. X-ray diffraction analysis (XRD) was used to investigate phase composition and crystal size of the milled powders. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM), respectively examined the microstructure of the prepared powder powders and sintered nanocomposites. Then, various properties of the sintered samples are measured, including physical, electrical and thermal properties and wear resistance. The obtained XRD technique and TEM images showed decreases in the crystal and particle size of milled samples reaching up to 14.08 and 28.30 nm, respectively for the sample contained 8 vol. % SiC + 0.8 vol. % graphene (SG8). A surprising improvement in the mechanical properties of up to 809.15, 341.84 MPa and 336.56 GPa for microhardness, strength and longitudinal modulus for the sample containing the highest reinforcements, achieving an improvement of up to 122, 61.37 and 41 percent compared to the Cu matrix. Moreover, there was a noticeable improvement in the coefficient of thermal expansion (CTE) and wear rate values of the samples by increasing the percentages of hybrid reinforcements in the examined sintered nanocomposite samples. The Sample SG8 recorded the lowest value, decreasing by about 50.2 and 76.5% compared to the SG1 sample. Finally, adding reinforcements to the Cu matrix had a negative effect on the relative density and electrical conductivity, and the lowest values was 92.94% and8.59 × 106 S/m, respectively for the SG sample.
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To improve the wear resistance of the materials used for blades in engineering machinery, this study focused on the microstructural characteristics, mechanical properties, and wear behavior of HB500 grade wear-resistant steel developed using an optimized heat treatment system. To improve the temperature uniformity of the heat treatment furnace, the method of cyclic heating was used to heat the components. Carefully designing the quenching equipment, such as using a cross-shaped press, was employed to enhance the quenching effect and reduce the deformation of the steel plates. The crystal orientation analysis revealed a uniform and fine-grained microstructure, primarily characterized by plate-type tempered martensite, which indicated a good hardenability. The microstructure observations showed that the width of martensite is approximately 200 nm, with a significant presence of dislocations and carbides. Tensile tests and multi-temperature gradient impact tests indicated superior mechanical properties compared to similar grade wear-resistant steels, including a Rockwell hardness of 53, tensile strength of 1610 MPa, yield strength of 1404 MPa, and total elongation around 12.7%. The results of friction and wear experiments indicate that the wear rate decreases as the load increases from 100 N to 300 N, demonstrating an excellent wear resistance under a large load. Observations of the worn surfaces indicated that the wear mainly involved adhesive wear, fatigue wear, and oxidative wear. The properties' improvements were attributed to microstructure refinement and precipitation strengthening. This study indicates that designing a heat treatment system to control temperature uniformity and stability is feasible.
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Lubricating hydrogel coatings on inert rubber and plastic surfaces significantly reduce friction and wear, thus enhancing material durability and lifespan. However, achieving optimal hydration lubrication typically requires a porous polymer network, which unfortunately reduces their mechanical strength and limits their applicability where robust durability and wear-resistance are essential. In the research, a hydrogel coating with remarkable wear resistance and surface stability is developed by forming a semi-interpenetrating polymer network with polymer substrate at the interface. By employing a good solvent swelling method, monomers, and photoinitiators are embedded within the substrates' subsurface, followed by in situ polymerization under ultraviolet light, creating a robust semi-interpenetrating and entangled network structure. This approach, offering a thicker energy-dissipating layer, outperforms traditional surface modifications in wear resistance while preserving anti-fatigue, hydrophilicity, oleophobicity, and other properties. Adaptable to various rubber and plastic substrates by using suitable solvents, this method provides an efficient solution for creating durable, lubricating surfaces, broadening the potential applications in multiple industries.
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This study examines the effects of different addition levels of tungsten (W) content on the microstructure, corrosion resistance, wear resistance, microhardness, and phase composition of coatings made from FeCoCrNiAl high-entropy alloy (HEA) using the laser cladding technique. Using a preset powder method, FeCoCrNiAlWx (where x represents the molar fraction of W, x = 0.0, 0.2, 0.4, 0.6, 0.8) HEA coatings were cladded onto the surface of 45 steel. The different cladding materials were tested for dry friction by using a reciprocating friction and wear testing machine. Subsequently, the detailed analysis of the microstructure, phase composition, corrosion resistance, wear traces, and hardness characteristics were carried out using a scanning electron microscope (SEM), X-ray diffractometer (XRD), electrochemical workstation, and microhardness tester. The results reveal that as the W content increases, the macro-morphology of the FeCoCrNiAlWx HEA cladding coating deteriorates; the microstructure of the FeCoCrNiAlWx HEA cladding coating, composed of µ phase and face-centered cubic solid solution, undergoes an evolution process from dendritic crystals to cellular crystals. Notably, with the increase in W content, the average microhardness of the cladding coating shows a significant upward trend, with FeCoCrNiAlW0.8 reaching an average hardness of 756.83 HV0.2, which is 2.97 times higher than the 45 steel substrate. At the same time, the friction coefficient of the cladding coating gradually decreases, indicating enhanced wear resistance. Specifically, the friction coefficients of FeCoCrNiAlW0.6 and FeCoCrNiAlW0.8 are similar, approximately 0.527. The friction and wear mechanisms are mainly adhesive and abrasive wear. In a 3.5 wt.% NaCl solution, the increase in W content results in a positive shift in the corrosion potential of the cladding coating. The FeCoCrNiAlW0.8 exhibits a corrosion potential approximately 403 mV higher than that of FeCoCrNiAl. The corrosion current density significantly decreases from 5.43 × 10-6 A/cm2 to 5.26 × 10-9 A/cm2, which suggests a significant enhancement in the corrosion resistance of the cladding coating.
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In order to improve the surface quality of copper after laser remelting, this article took laser frequency, pulse width, and energy density as the research objects and used scanning electron microscopy (SEM), a laser confocal three-dimensional measurement instrument, hardness tester, and friction and wear measurement instrument to study the surface morphology, surface roughness, microhardness, and wear resistance of copper, respectively. The results indicate that the frequency, pulse width, and energy density of laser remelting could directly affect the surface quality of the sample, but the influence of frequency and pulse width was more significant. When the laser remelting frequency was 10 Hz, the pulse width was 10 ms, and the energy density was 132.69 J/mm2, the sample exhibited good surface morphology, roughness, and wear resistance. The relevant research in this article can provide a good reference for the laser surface treatment of copper-based materials.
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In this study, the microstructural properties, wear resistance, and corrosion behavior of H111 hot-rolled AA5754 alloy before heat treatment, after homogenization, and after aging were examined. The microstructure was mainly composed of the scattered forms of black and gray contrast particles on the matrix and precipitations were observed at the boundaries of the grain. The as-rolled material exhibited a dense pancake-shaped grain structure, which is typical of as-rolled material. Observation along the L-direction did not yield distinct demarcations among the grains and was not uniformly distributed, with precipitates at the grain boundary. When they aged, there was a parallel increase in fine and huge black and gray contrast particles in the zone. Therefore, it could be stated that the amount of fine grains increased due to the rise in the homogenization process. The rolled base metal with the grain orientation was found to be parallel to the rolling direction. On the other hand, the coarse grains were clearly observed in the aging heat-treatment condition. The grains had an elongated morphology consistent with the rolling process of the metal before the heat-treatment process. The aged alloy had the highest hardness with a value of 86.83 HB; the lowest hardness was seen in the alloy before heat treatment with a value of 68.67 HB. The weight loss and wear rate of this material at the end of 10,000 m were, respectively, 1.01 × 10-3 g and 5.07 × 10-9 g/Nm. It was observed that the alloy had the highest weight loss and worst wear resistance before heat treatment. Weight loss and wear rates at the end of 10,000 m were, respectively, 3.42 × 10-3 g and 17.08 × 10-9 g/Nm. According to these results, the friction coefficients during wear were parallel and the material with the lowest friction coefficient after aging was 0.045. While the alloys corroded after aging showed more weight loss, the alloys corroded before heat treatment exhibited better corrosion behavior. Among the alloys, the least weight loss after 24 h was observed in the alloy that was corroded before heat treatment and this value was 0.69 × 10-3 mg/dm2. The highest weight loss was observed in the aged alloy with a value of 1.37 × 10-3 mg/dm2. The alloy before heat treatment, which corroded after casting, showed the lowest corrosion rate with a value of 0.39 × 10-3 mg/(dm2·day) after 72 h. The alloy that was corroded before heat treatment showed the best corrosion behavior by creating a corrosion potential of 1.04 ± 1.5 V at a current density of -586 ± 0.04 µA/cm2. However, after aging, the corroded alloy showed the worst corrosion behavior with a corrosion potential of 5.16 ± 3.3 V at a current density of -880 ± 0.01 µA/cm2.
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The spinning cup, a crucial component of textile equipment, relies heavily on 2A12 aluminum alloy as its primary raw material. Commonly, electroplating and chemical nickel-phosphorus (Ni-P) plating are employed to improve the surface characteristics of the object. Nevertheless, due to the growing expectations for the performance of aluminum alloys, the hardness and wear resistance of Ni-P coatings are no longer sufficient to fulfill industry standards. This study primarily focuses on the synthesis of Ni-B-PTFE nanocomposite chemical plating and its effectiveness when applied to the surface of 2A12 aluminum alloy. We examine the impact of the composition of the plating solution, process parameters, and various other factors on the pace at which the coating is deposited, the hardness of the surface, and other indicators of the coating. The research findings indicate that the composite co-deposited coating achieves its optimal surface morphology when the following conditions are met: a nickel chloride concentration of 30 g/L, an ethylenediamine concentration of 70 mL, a sodium borohydride concentration of 0.6 g/L, a sodium hydroxide concentration of 90 g/L, a lead nitrate concentration of 30 mL, a pH value of 12, a temperature of 90 °C, and a PTFE concentration of 10 mL/L. The coating exhibits consistency, density, a smooth surface, and an absence of noticeable pores or fissures. The composite co-deposited coating exhibits a surface hardness of 1109 HV0.1, which significantly surpasses the substrate's hardness of 232.38 HV0.1. The Ni-B-PTFE composite coating exhibits an average friction coefficient of around 0.12. It has a scratch width of 855.18 µm and a wear mass of 0.05 mg. This coating demonstrates superior wear resistance when compared to Ni-B coatings. The Ni-B-PTFE composite coating specimen exhibits a self-corrosion potential of -6.195 V and a corrosion current density of 7.81 × 10-7 A/cm2, which is the lowest recorded. This enhances its corrosion resistance compared to Ni-B coatings.
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Soil-engaging components play a critical role in agricultural production and engineering construction. However, the soil-engaging components directly interacting with the soil often suffer from the problems of high resistance, adhesion, and wear, which significantly reduce the efficiency and quality of soil operations. A large number of featured studies on the design of soil-engaging components have been carried out while applying the principles of bionics extensively, and significant research results have been achieved. This review conducts a comprehensive literature survey on the application of biomimetics in the design of soil-engaging components. The focus is on performance optimization in regard to the following three aspects: draught reduction, anti-adhesion, and wear resistance. The mechanisms of various biomimetic soil-engaging components are systematically explained. Based on the literature analysis and biomimetic research, future trends in the development of biomimetic soil-engaging components are discussed from both the mechanism and application perspectives. This research is expected to provide new insights and inspiration for addressing related scientific and engineering challenges.
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This study investigates the phase composition, microstructure, and their influence on the properties of Mo-W-C nanocomposite films deposited by dual-source magnetron sputtering. The synthesised films consist of metal carbide nanograins embedded in an amorphous carbon matrix. It has been found that nanograins are composed of the hexagonal ß-(Mo2 + W2)C phase at a low carbon source power. An increase in the power results in the change in the structure of the carbide nanoparticles from a single-phase to a mixture of the ß-(Mo2 + W2)C and NaCl-type α-(Mo + W)C(0.65≤k≤1) solid-solution phases. The analysis of electrical properties demonstrates that the nanograin structure of the films favours the occurrence of hopping conductivity. The double-phase structure leads to a twofold increase in the relaxation time compared to the single-phase one. Films with both types of nanograin structures exhibit tunnelling conductance without the need for thermal activation. The average distance between the potential wells produced by the carbide nanograins in nanocomposite films is approximately 3.4 ± 0.2 nm. A study of tribomechanical properties showed that Mo-W-C films composed of a mixture of the ß-(Mo2 + W2)C and α-(Mo + W)C(0.65≤k≤1) phases have the highest hardness (19-22 GPa) and the lowest friction coefficient (0.15-0.24) and wear volume (0.00302-0.00381 mm2). Such a combination of electrical and tribomechanical properties demonstrates the suitability of Mo-W-C nanocomposite films for various micromechanical devices and power electronics.