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Objectives: This study evaluated the mechanical, optical, microstructural, surface, and adhesive behavior of a 3D printing resin comparing it with a machinable resin composite., Materials and Methods: Specimens of different sizes and shapes were either printed (Vitality, Smart Dent) or machinable (Grandio Blocs, Voco GmbH) resin composites with similar composition were prepared. Surface and mechanical characterization were performed with Knoop hardness, flexural strength (three-point-bending), and elastic modulus tests. The wear of the tested materials was evaluated against steatite antagonists. The optical properties stability (color change, ΔE 00, and translucency, TP 00 ) were observed after staining in red wine. In addition, the bond strength of the resin composites to two resin cement protocols were investigated with microshear bond strength tests at baseline and after thermocycling. Scanning electron microscope (SEM) coupled with Energy-Dispersive X-ray Spectroscopy (EDS) was used for microstructural and chemical characterization. Statistical analyses were performed with t- and ANOVA tests., Results: Hardness values (132.76 (16.32) KH- Machinable and 35.87 (2.78) KH - Printed), flexural strength (172.17 (26.99) MPa - Machinable and 88.69 (8.39) MPa - Printed), color and translucency change (1.86 (0.31)/0.06 - Machinable and 3.73 (0.36)/9,16- Printed), and wear depth (24.97 mm (3.60)- Machinable and 7.16 mm (2.84) - Printed) were statistically different. Average Regarding bond strength, mean values (MPa) for non-aged and aged groups were respectively 21.76 (6.64) / 31.9 (12.66) for Bifix cement (Voco GmbH, Cuxhaven, Germany) and 26.75 (5.14) / 24.36 (6.85) for Variolink cement (Ivoclar Vivadent, Schaan, Liechtenstein) in Printed and 17.79 (3.89) / 9.01 (3.36) ) for Bifix cement and 22.09 (6.55) / 11.01 (3.77) for Variolink cement in Machinable materials. The material and aging factors did affect bond strength but the cement factor did not (p = 0.202). No statistical differences were observed for mean roughness (Ra) between materials. The better dispersion and larger size of the inorganic particles in the Machinable resin were contrasted with the clustered smaller particles of printed resin, under SEM., Conclusions: The mechanical properties and color stability of the machinable resin were superior to those of the printed resin, probably due to the greater amount and dispersion of inorganic particles in the Mach resin, but bond strength after aging was stronger and more stable in the printed resin., Clinical Relevance: 3D-printed resin composites with similar compositions to machinable resin composites do not necessarily exhibit the same properties, which can impact clinical performance. Understanding these differences can assist manufacturers in improving their materials and help clinicians distinguish between materials appropriate for provisional and final restorations., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

TiAlSiN is a potential protection coating for die steel to improve the surface hardness, anti-wear performance and suitability. In the present study, TiAlSiN is deposited on H13 die steel by high power impulse magnetron sputtering and the effects of bias voltage, deposition temperature, and film thickness on the performance of coatings are studied. The microstructure, mechanical and tribological properties of coatings are analyzed by energy dispersive spectrometer, X-ray diffraction, nanoindentation, friction and wear tests. The results show that with the changes of sputtering parameters, the content of Ti, Al, Si, and N fluctuates slightly. With the increase of bias voltage, deposition temperature and film thickness, the diffraction peaks of Ti3Al2N2 phase become wider. Higher bias voltage, deposition temperature, and film thickness are beneficial for obtaining coatings with high hardness, and strong wear resistance. By observing the surface morphology of coatings after grinding with Si3N4 balls, it was found that the wear mechanism of coatings contains abrasive wear, fatigue wear, and oxidative wear. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Highlights In polymer‐based dental composites, wear is a three‐body wear system mainly abrasive, because of the food particles and wear products suspended in the oral cavity, which are transferred to the microcavities of the surface of the replacements. Due to this fact, the incorporation of nanodiamond as reinforcement in these polymer–matrix composites, which promotes the creation of a solid lubricant tribofilm surface could be advantageous. With the reinforcement of nanodiamonds, BisGMA/TEGDMA‐based composites increase their microhardness by 95%–420%. A maximum hardness exceeding 65 HV is achieved with a reinforcement of 3.2 wt%. The specific wear rate of neat BisGMA/TEGDMA is near 10−4 mm3/Nm and the Archard's coefficient is 2.6 × 105. The incorporation of a content of 1.6 wt% ND is enough to cause a diminution of ~78% in the friction coefficient and a reduction of the specific wear rate and Archard's coefficient of ~50%. Nevertheless, the addition of relatively high contents reduces the effectiveness of photoinitiation and photocuring, which is related to the scattering and absorption of light radiation by ND. This causes a significant decline in elastic properties starting at 50 μm from the surface. Photocuring polymer resin was successfully reinforced with nanodiamonds. Microhardness increases from 95% up to 420%, close to commercial composites. Friction coefficient and wear rate are reduced with 1.6 wt% nanodiamonds. High levels of reinforcement reduce the effectiveness of photocuring. [ABSTRACT FROM AUTHOR]

In this study, the effects of hot dip aluminizing (HDA) (90 s at 725°C) and diffusion annealing on the microstructural and tribological properties of DP800 steel were investigated. After HDA treatment, one of the sample was left to cool in air (HDA-1) and the other one left to cool in air after being subjected to a diffusion annealing for 1 hour in an oven set at 300°C (HDA-2). Evolution in mechanical and tribological properties depending on the developments in the coating microstructure investigated in terms of hardness and wear behaviour, respectively. Mechanical characterization results show that diffusion annealing increases the hardness value of hot dip aluminized steel to 1100 HV values. Considering the wear ball volume and friction coefficients, the most advanced tribological properties were observed in the diffusion-annealed HDA process (HDA-2). [ABSTRACT FROM AUTHOR]

This article explores the properties of composite materials employed in dental fillings. A traditional nano-hybrid composite containing nanofiller particles exceeding 82% by weight served as a benchmark. The remaining samples were fabricated from ormocer resin, maintaining an identical nanofiller content of 84%. In all specimens, the nanoparticles were dispersed randomly within the matrix. This study presents findings from investigations into surface geometry, hardness, wettability, and tribological behavior. The microscopic observations revealed that ormocer-based samples exhibited greater surface roughness than those composed of the traditional composite. Hardness testing indicated that both ceramic addition and sample preparation significantly influenced mechanical properties. Ceramic-enhanced samples demonstrated superior hardness, surpassing the reference composite by 30% and 43%, respectively. Contact angle measurements revealed hydrophilic characteristics in the classic composite, contrasting with the hydrophobic nature of ceramic-containing samples. Tribological evaluations revealed the superiority of the classic composite in terms of friction coefficients and volumetric wear compared to ormocer-based materials. [ABSTRACT FROM AUTHOR]

This investigation employs the salt bath nitriding to extend the service life and improve the surface characteristics of AISI 52100, commonly employed in bearing applications. A wear test was conducted using a pin-on-disc device according to the ASTM G-99 standard, and the findings show a 30% reduction in wear loss. Sliding wear experiments were conducted at 1.5 m/s with a 5 N force at room temperature on uncoated and nitrided pins which was obtained as optimum value from RSM. The three variables and five levels of central composite design (CCD) were utilized to reduce the number of trials and the model relations were examined through ANOVA. Surface hardness, friction coefficient, wear coefficient, and loss in wear are measured over pins without coating and nitride pins. Investigations were done into how 5W30 oil affected passive and drip lubrication. Nitride substrates had a hardness of 590 HV. Also, nitriding has a favorable effect on the friction coefficient, lowering it by up to 23%. The 5W30 lubricant will further decrease the friction coefficient. The lowest friction coefficient was seen with the addition of 14% drip oil lubrication. Significantly less wear loss in the pin was caused by a combination of high hardness and low friction coefficient. [ABSTRACT FROM AUTHOR]

Ti-Ta coatings were deposited on titanium alloy by electrospark deposition in the anode mixture of titanium granules and tantalum powder in an argon atmosphere. The cathode weight gain kinetics, tantalum concentration, structure, oxidation resistance, microhardness, and tribotechnical properties of the coatings were studied. It was shown that, with increasing tantalum concentration in the anode mixture, the net cathode gain during 10 min of treatment increased monotonically. The average thickness of the deposited coatings varied in the range from 30.9 to 39.1 µm. The concentration of tantalum in the coating composition increased with increasing tantalum powder concentration in the anode mixture. The coating structure was dense without longitudinal and transverse cracks. With an excess of tantalum powder in the anode mixture, the discharge energy was not enough to completely melt it. The phase composition included α-Ti and a bcc tantalum solid solution in β-Ti. With increasing powder concentration in the anode mixture, the intensity of the bcc-phase peaks increased relative to the α-Ti peaks. The surface hydrophobicity of Ti-Ta coatings was higher than that of uncoated Ti6Al4V titanium alloy. The developed method can be used to produce Ti-Ta coatings with up to 5.9 times higher oxidation resistance compared to Ti6Al4V alloy. The high oxidation resistance of Ti-Ta coatings is explained by the formation of a dense and durable TiO2 layer. The surface microhardness of Ti-Ta coatings ranged from 4.72 to 4.91 GPa. The friction coefficient was in the range of 0.87–0.97. The wear resistance was 23 to 36 times higher as compared to the titanium alloy. [ABSTRACT FROM AUTHOR]

In the present study, an attempt was made to develop surface cladding on AISI 304 steel by utilizing a mixture of Ni and 15% SiC powder via microwave energy. The microwave cladding process on the AISI 304 was carried out in the in-house developed set-up on the microwave. The microwave cladding process was carried out on 900 W with a 2.45 GHz frequency for 120 seconds irradiation time. SEM images showed a uniform cladding layer and cladding surface with SiC wt.% of 15 and irradiation time of 120 seconds. The energy dispersive X-ray (EDX) pattern of AISI 304 cladding surface coating with Ni and 15% SiC. EDX pattern showed the element weight percent of Ni, Fe, Cr, Si, O, and C is 58%, 22%, 4.98%, 5.97%, 1.45%, and 7.6%, respectively. EDX pattern for the cladding layer showed the element's weight percent of Fe, Ni, Si, C, O, and Cr is 46.34%, 27.3%, 11.12%, 7.9%, 4.2%, and 3.14%, respectively. XRD of the cladding surface shows the presence of Fe, FeNi3, NiSi2, Cr2C, Ni3C, Fe2SiO4, and SiC phases. The average hardness of the cladding surface and cladding layer was found to be about 324 HV and 306 HV, respectively. The hardness of the cladding surface was improved by about 46.60%. Fatigue strength of AISI 304 without and with the microwave cladding of the mixture of 15% SiC and Ni powder was found to be 210 MPa and 245 MPa, respectively, at the cyclic load of 1 × 107 cycles. Though, a micrograph of AISI 304 with the microwave cladding of the mixture of 15% SiC and Ni powder shows the fatigue wear, wear debris, and plastic flow of SiC particles after the wear testing. [ABSTRACT FROM AUTHOR]

Abstract TiAlSiN is a potential protection coating for die steel to improve the surface hardness, anti-wear performance and suitability. In the present study, TiAlSiN is deposited on H13 die steel by high power impulse magnetron sputtering and the effects of bias voltage, deposition temperature, and film thickness on the performance of coatings are studied. The microstructure, mechanical and tribological properties of coatings are analyzed by energy dispersive spectrometer, X-ray diffraction, nanoindentation, friction and wear tests. The results show that with the changes of sputtering parameters, the content of Ti, Al, Si, and N fluctuates slightly. With the increase of bias voltage, deposition temperature and film thickness, the diffraction peaks of Ti3Al2N2 phase become wider. Higher bias voltage, deposition temperature, and film thickness are beneficial for obtaining coatings with high hardness, and strong wear resistance. By observing the surface morphology of coatings after grinding with Si3N4 balls, it was found that the wear mechanism of coatings contains abrasive wear, fatigue wear, and oxidative wear.

Industrial components subjected to severe conditions need high wear-resistant alloys to enhance durability and reliability, leading to substantial reductions in maintenance costs and downtime. Their composition and microstructure determine hardness, toughness, friction, and resistance to wear. Fe–Cr–B-based alloys, with their excellent wear resistance attributes, are important in various industrial applications. In this review, the tribological performance of Fe–Cr–B-based alloys is concisely described. First, the phase and microstructural analysis of the alloys is discussed, followed by the correlation with their tribological properties. The variations in hardness across different alloy systems are also presented. The collective information provided could catalyze the development of more efficient Fe–Cr–B-based alloy systems having improved mechanical and tribological performance.

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The effect of coating thickness (CT) on the microstructures, hardness, and wear of cold sprayed Ti-6Al-4V (CS-Ti64) coatings was systematically investigated since the prolonged high pressure CS deposition could change their microstructures and porosity levels. In addition, the CT was relatively important for their durability, performance, and service life. Therefore, the CS-Ti64 coatings with different CT of 100-3000 µm were prepared on commercially available Ti64 (CA-Ti64) substrates via high pressure CS processes. The CS-Ti64 coatings had low porosity levels wherewith severely deformed Ti64 particles with a crescent-shape could be seen in their cross-sectional microstructures. The hardness of the CS-Ti64 coatings increased with increased CT probably due to their lowered bulk porosity levels associated with longer high pressure CS deposition. As a result, the increased CT from 100 to 3000 µm resulted in a 9.8% decrease in the wear of the CS-Ti64 coatings. The wear of the CS-Ti64 coating with 3000 µm was 16.8% lower than that of the CA-Ti64 as all the CS-Ti64 coatings had lower wear than the CA-Ti64. It could be concluded that the prolonged high pressure CS deposition for the thick CS-Ti64 coatings had an influence on their porosity, hardness, and wear.

The hybrid composite is fabricated by powder metallurgy technique. The addition of ceramic reinforcements to the matrix phase helps in attaining tribological properties. Initially, the metal powders are prepared by atomization and reduction process. To reduce oxidation of pure metals, electrolytic process is carried out. The crushing, milling and sintering process are carried after atomization to obtain fine grain sized particles; these are then characterized using Scanning Electron Microscope (SEM), X-Ray Diffractometer (XRD). The obtained particles are then blended and compacted to attain better hardness and wear resistant of the materials. The hybrid composites prepared for the analysis by reinforcing 15%Ni-8%Sn-4%B4C to the matrix phase Cu. The pin-on-disc method is incorporated to study the wear rate, hardness and co-efficient of friction. By varying the contribution parameters such as load 10 N-25 N, sliding distance 400 mm-1000 mm and sliding speed, the matrix phase materials exhibited rigorous wear, whereas the reinforced hybrid composite (Cu-15%Ni-8%Sn-4%B4C) provide good strength and wear resistant and also reduced volume loss of 25×10–5cm3and 110×10–5 cm3 for 10 N load with 400 mm and 1000 mm sliding distance even at sintering temperature of 900°C. The microstructure and morphology of the worn surface is analyzed using Scanning Electron Microscopy images. The sintered density of the hybrid composite is less due to reduced number of pores and so material defect is also condensed.

The paper presents the results of contact strength and tribological property tests of spare parts made of a popular resin using a 3D DLP printing technology. Two printer models by the same manufacturer were used in the study. The post-processing technique, which shapes the final functional properties, was diversified. Surface performance properties were compared, i.e. Shore hardness, indentation hardness, Martens hardness, elastic modulus, and parameters related to surface creep and relaxation. Tribo-logical durability in rotary motion and tribological wear in reciprocating linear motion were also evaluated using micro- and nanotribometers. This was followed by surface analyses of the friction track of the analysed materials using microscopic methods: a scanning electron microscope, a WLI interferometric microscope, and an optical microscope. The results were statistically processed and the relationship between the parameters determined in the indentation test was determined.

The significance of biosilica in the silver-grey magnesium (SG-Mg-10% Si) metal is to enhance its mechanical and tribological characteristics. The Bermuda grass was used to make the biosilica. This investigation employed SG-Mg-10%Si and biosilica reinforcement (0, 5, 10, 15, and 20 wt. %) as the composite matrix. Due to increased bonding between the components of the composite, the SG-Mg-10%Si/biosilica composite created by the stir casting process demonstrated remarkable mechanical and tribological qualities. Further testing was done to assess the mechanical and tribological characteristics of the composite specimens, including density, porosity, hardness, tensile strength, and wear rate. SG-Mg-10%Si was contrasted with all these outcomes. The density plummeted at a rate of 1.49 (g/cm3) when the weight percentage of biosilica particles was added. Minimum and maximum hardness values for the composite's 20% of reinforced biosilica particles are 93.4 VHN and 125 VHN, respectively, and the tensile strength is 633.18 MPa. In order to determine the wear rate of SG-Mg-10%Si/biosilica composites, a dry sliding pin-on-disc tribometer was employed. When biosilica particles were added, the rate of wear of the manufactured SG-Mg-10%Si/ biosilica composites gradually reduced. When subjected to loads of 40 N and sliding distances of 1500 m and 2500 m, respectively, the composite with 20wt.% of biosilica reinforcement had improved anti-wear properties of 10.257 mg/m × 10−3 and 13.334 mg/m × 10−3. Field emission scanning electron microscope (FESEM) was utilized to examine how reinforcement was distributed across the matrix and showed the uniform distribution and strong bonding in the composites, together with a visible biosilica reinforcing interface. The benefits of the SG-Mg-10%Si/biosilica composites are enhanced mechanical and tribological properties and utilized in several applications like automobile, aeronautical and space research, sports goods, and medical types of equipment, reduced expenditure, and saved manufacturing time and exertion. [ABSTRACT FROM AUTHOR]

In this study, tungsten–copper (W–Cu) composite was fabricated using the sintering process to examine the corrosion, wear and hardness of the fabricated samples at three different temperatures of 1050, 1150 and 1300 °C. The potentiodynamic polarization behavior of the composite samples was evaluated in 3.5% NaCl solution containing different benzotriazole inhibitors. Finally, the microstructure of the W–Cu composite was examined by SEM, TEM, XRD and EDS analyses. The XRD results on the milled samples showed that the optimal conditions were obtained with a ball to powder ratio of 16:1 and a milling time of 15 h, so that the crystals with a size of 16.76 nm were obtained. Also, the highest hardness (185 HV) and relative density (97.34%) were obtained in the samples sintered at 1300 °C. With increasing the wear force, the work hardening increased in the mechanically mixed layer, which led to a rise in the wear rate and a decrease in the friction coefficient. The corrosion behavior of the composite indicated that by addition of 200 ppm inhibitor in the corrosion solution, the corrosion current density decreased from 3.73 to 0.59 μA/cm2 and the corrosion potential improved from − 630.46 to − 336.28 mVSCE. [ABSTRACT FROM AUTHOR]

AISI 316L austenitic stainless steel superficially modified by the solid nitriding technique was investigated at different nitriding times (2, 4, 6, 8, 12 and 24 h) and at 450 °C. The microstructural characterization was conducted using scanning electron microscopy (SEM) analysis and X-ray diffraction analyses, finding the presence of Fe2–3N, Fe4N and Cr2N, among others. The mechanical behavior of the modified surfaces was carried out by developing hardness profiles and relating it with the nitride layer thickness evaluated using scanning electron microscopy (SEM), obtaining layers up to 70 µm wide. The nitrogen diffusion produced species above and below the surface sample with a transformation from the austenitic phase to an expanded austenite (γN) phase, which is responsible for producing an increase in hardness of up to 1200 HV in the samples treated at 24 h, which is four times higher than the untreated steels. Wear evaluations of the obtained layers were performed using a pin-on-disk system under zero lubrication, indicating that the samples with 12 and 24 h of treatment present the best wear resistance promoted by an oxidative–adhesive mechanism. The obtained results are positively comparable with those of the ion nitriding technique but with a lower implementation cost. [ABSTRACT FROM AUTHOR]

This paper presents and demonstrates the development of a new lightweight coating for aluminum alloy from a novel multicomponent alloy based on the AlSiMgCu system. The coating was applied using a newly designed approach that combined high velocity oxy-fuel (HVOF) and plasma spraying processes. This hybrid technique enables the deposition of coatings with enhanced performance characteristics. The optical microscopy (OM) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM + EDS) revealed a strong adhesion and compaction between the multicomponent coating and the A6061 substrate. The new coating improved hardness by 50% and increased electrical conductivity by approximately 3.3 times compared to the as-cast alloy. Corrosion tests showed a lower corrosion rate, comparable to thermally treated A6061 alloy. Tribological tests indicated over 20% reduction in friction and over 50% reduction in wear rate. This suggests that multicomponent aluminum coatings could improve automotive and parts in contact with hydrogen by enhancing hydrogen fragilization resistance, corrosion resistance, electrical conductivity, and wear properties, with further optimization of thermal spraying potentially boosting performance even further. [ABSTRACT FROM AUTHOR]

High entropy alloy composites (HEACs) have recently been explored for use in industrial applications. This study investigates the impact of particle size (micro or nano) and content (5 and 10 wt%) of YSZ on the microstructure and tribological properties of AlCoCrFeNi. The samples were prepared using a combination of mechanical alloying and spark plasma sintering. XRD results and Rietveld analysis reveal that HEACs with micro-sized YSZ have a higher BCC/FCC ratio. FESEM and EDS results confirmed the evolution of Al-rich regions in the vicinity of the reinforcements. Especially, in HEA-10NanoYSZ-sample, due to higher interfacial regions, a huge amount of Al-rich phase has been formed which yields the reduction of BCC phase content in this sample. Microhardness and pin-on-disc wear tests show that the samples reinforced with microparticles demonstrate better performance compared to nanocomposite samples. For example, HEA-10MicroYSZ-sample exhibits the highest hardness (5.1 GPa) and the lowest wear characteristics (with a coefficient of friction of 0.8 and a wear rate of 4 × 10−4 mm3/N.m). This can be correlated to the higher hardness and BCC phase content, and grain boundary strengthening in the microcomposites. [ABSTRACT FROM AUTHOR]

MAX phases are intriguing materials due to their unique properties. However, each of these materials possesses its own weaknesses when subjected to service conditions. For example, while one MAX phase exhibits self-lubricating feature, it may not perform well under high load conditions. This study investigates the impact of adding chromium to Ti 2 AlC on microstructure and mechanical properties. Samples are prepared through ball-milling and spark plasma sintering (SPS), then analyzed using various techniques. The presence of different phases, including MAX phases (Ti 2 AlC and Cr 2 AlC), carbides (TiC and Cr 7 C 3), and low amounts of oxides, is identified. Hardness, fractography, and wear characteristics are assessed through indentation and sliding tests. The study correlates the wear rate of each sample with experimental (H/E) and theoretical indicators (B/G), showing the production of composites with improved properties suitable for diverse applications. [ABSTRACT FROM AUTHOR]

The wear and corrosion resistance of 316L austenitic stainless steel after strain hardening were studied. 316L austenitic stainless steel was composed of a large amount of austenite and a small fraction of martensite. After strain hardening at room temperature, the contents of phases were not changed basically. With the increase of pre-strain deformation, the microhardness of the surface and cross-section slightly increased, and the microhardness of the sample with pre-strain deformation of 20% was the largest. When the pre-strain deformation was greater than 5%, the surface microhardness was greater than the cross-sectional microhardness. The dynamic average friction coefficients of the stainless steel after pre-strain deformation of 0%, 5%, 10%, and 20% were 0.67, 0.57, 0.2, and 0.12, respectively. The friction coefficient of the samples gradually decreased with the increase of strain hardening. The wear resistance of 316L stainless steel was improved after pre-strain deformation. The steel with pre-strain deformation of 20% had a small abrasive scratch depth and low friction coefficient, which exhibited good wear resistance. The corrosion resistance of the samples after strain hardening deteriorated for the initial state without immersion due to the existence of defects. The corrosion resistance of the sample with pre-strain deformation of 5% after soaking for 3 days was the best, compared with the other as-strained samples. [ABSTRACT FROM AUTHOR]

In this study, the researchers have attempted to reinforce ZK60 alloys with 5% SiC, 10% SiC, 5% B4C, 10% B4C and 5%SiC + 5%B4C microparticles and investigated the dry wear behavior of these composites. The reinforced composites were produced by the stirred casting method under the atmosphere of SF6. The high-temperature oxidation tendency of Mg and B elements can cause the oxidized-unsuccessful product in the stirred casting process. Therefore, the researchers used the semi-solid temperature stirring method in production as a new solution. The reinforced composites were homogenized at 420 °C for 24 hours and extruded at a rate of 2.25. Following the production process, all samples underwent microstructural characterization analyses, hardness tests, compression tests and dry wear tests. Comparative analysis was done between the results of unreinforced ZK60 alloy and composites from compression and wear tests. This study's results reveal a superior enhancement; the addition of 5% SiC increased the compressive strength of ZK60 alloy by 15%, while the addition of 5% B4C increased by 26%. Furthermore, adding the 5%SiC reinforcement reduced the wear rate by 4.3%, and the 5% B4C reinforcement reduced the wear rate by 11.1%. [ABSTRACT FROM AUTHOR]

The hybrid composite is fabricated by powder metallurgy technique. The addition of ceramic reinforcements to the matrix phase helps in attaining tribological properties. Initially, the metal powders are prepared by atomization and reduction process. To reduce oxidation of pure metals, electrolytic process is carried out. The crushing, milling and sintering process are carried after atomization to obtain fine grain sized particles; these are then characterized using Scanning electron Microscope (SEM), X-Ray Diffractometer (XRD). The obtained particles are then blended and compacted to attain better hardness and wear resistant of the materials. The hybrid composites prepared for the analysis by reinforcing 15%Ni-8%Sn-4%B4C to the matrix phase Cu. The pin-on-disc method is incorporated to study the wear rate, hardness and co-efficient of friction. By varying the contribution parameters such as load 10 N-25 N, sliding distance 400 mm-1000 mm and sliding speed, the matrix phase materials exhibited rigorous wear, whereas the reinforced hybrid composite (Cu-15%Ni-8%Sn-4%B4C) provide good strength and wear resistant and also reduced volume loss of 25x10-5cm³ and 110x10-5 cm³ for 10 N load with 400 mm and 1000 mm sliding distance even at sintering temperature of 900°C. The microstructure and morphology of the worn surface is analyzed using Scanning Electron Microscopy images. The sintered density of the hybrid composite is less due to reduced number of pores and so material defect is also condensed. [ABSTRACT FROM AUTHOR]

The wear of normalized (N) and dual-phase (DP) low-carbon (0.08% C) and medium-carbon (0.42% C) steels under air-jet erosion at 15° and 90° impact angles of alumina particles is studied. The DP steels are produced via intercritical annealing heat treatment of low- and medium-carbon steels at 745°C for various holding times (2, 3, and 4 min) followed by water quenching, which results in formation of a varying amount of martensite in the structure. The results indicate that the hardness and the UTS of the low- and medium-carbon dual-phase steels increase with increase in the martensite content. Material removal occurs by cracking, crater formation, and low-angle cutting at 90°, whereas ploughing and chipping of the material occur at 15°. [ABSTRACT FROM AUTHOR]

As-received (AsRec) EN24 steel was treated with conventional heat treatment (ConHeatTreat) without tempering followed by deep cryogenic treatment (DeepCryoTreat) as a supplemental treatment to study its tribological behaviour against alumina without or with mineral oil (MO) under different normal loads of 1 N and 5 N. The ConHeatTreat of the AsRec-EN24 obtained an 218.5% improvement in its hardness as the supplemental DeepCryoTreat of the ConHeatTreat-EN24 resulted in a 11.7% further improvement in its hardness. As a result, the ConHeatTreat-EN24 had the 67.5% and 56.3% lower wear volumes for 1 N and 5 N under dry condition and the 53.6% lower wear volume for 5 N under MO lubrication condition compared to those of the AsRec-EN24, respectively. The DeepCryoTreat-EN24 had the 11.5% and 39.7% lower wear volumes for 1 N and 5 N under dry condition and the unmeasurable wear volume for 5 N under MO lubrication condition compared to those of the ConHeatTreat-EN24, respectively. It could be concluded that the supplemental DeepCryoTreat further improved the hardness and thereby the abrasive wear resistance of the ConHeatTreat-EN24 under both dry and lubrication conditions.

The results of studies of the influence of Y as a reactive element on the properties of TiAlN coatings obtained by the method of vacuum-arc deposition are given. Changes in the structure and properties were analyzed using SEM in combination with EDX, XRD, indentation analysis and wear analysis. It is shown that the presence of Y changes the crystalline phase of the Ti0.6Al0.34Y0.06N coating. It consists of a combination of a cubic NaCl structure (basic phase) and a wurtzite structure (additional phase). In addition, it leads to a small grain size (12 nm) and a nano-columnar structure. The high hardness is partly the result of solution hardening due to the inclusion of larger Y atoms in the TiAlN lattice at the locations of the metal atoms. The reduced grain size of 12 nm also helps to increase the hardness of the coating. The hardness is 31 ± 2.5 GPa, the modulus of elasticity is 394.8 ± 35.8 GPa. The residual stress is approximately three times (−3352 ± 64 MPa) higher than the TiAlN coating (−720 MPa). In addition, a high level of compressive stress contributes to an increase in hardness, since defects responsible for their own compressive stress are an obstacle to dislocation movement. The improved hardness of the experimental coating can be explained by a triple effect: solution strengthening, grain grinding and high residual compressive stress. The addition of Y indicates a slower growth of the oxide layer on the surface of the coating during the wear test. After the addition of Y, Y ions preferentially separate at the grain boundaries and therefore effectively delay the inward diffusion of oxygen. The addition of Y promotes the formation of dense Al2O3, which is effective in restraining diffusion and therefore protects the coating from oxidative wear.

The material design concept of high-entropy alloy (HEA) is proposed for Tribaloy alloys. In this research, three HEAs are created by mixing Co-based T-800 and Ni-based T-700 Tribaloy alloys in different ratios and fabricated via spark plasma sintering (SPS) process. The phase transformation behavior of the mixed powders of T-800 and T-700 is investigated with differential scanning calorimetry (DSC) analysis. The microstructures of the SPS specimens and solidified DSC samples of the created HEAs are studied using SEM and XRD, showing that they consist of fcc Co, Mo, and Ni solid solution with minor hcp Co solid solution, various Laves phase, mainly Co3Mo2Si, CoMoSi, Ni3Mo2Si, Mo2Si, and CrSi2, and complex intermetallic compounds. The hardness and dry-sliding wear resistance of the created SPS HEAs are evaluated and compared with the initial alloys (T-800 and T-700). It is shown that the hardness and wear resistance of T-800 are much higher than that of T-700, which is attributed to the excellent properties of element Co; the created HEAs exhibit better hardness and wear performance than T-700 but worse than T-800. The HEA having an equal mixture ratio of T-800 and T-700, with the largest configurational entropy of 1.58R, performs the best in wear resistance among the HEAs. [ABSTRACT FROM AUTHOR]

In this study, we have employed friction stir processing to strategically modify the microstructure of AA-Mg alloys, resulting in a direct enhancement of their mechanical properties. The experiments encompassed a range of tool speeds ranging from 800 to 1600 rpm and feed rates ranging from 20 to 80 mm/min. Employing a single-pass approach across all combinations, samples were extracted from the stir zone region to evaluate hardness and wear characteristics. The evaluation involved Vickers hardness tests to quantify hardness and pin-on-disc tests to examine the tribological attributes of the specimens. The worn-out surfaces of the specimens were examined using scanning electron microscope imagery. There is a substantial increase in hardness when compared with the base material, i.e., 78 HVN is up to 96 HVN for 20 mm/min at 1200 rpm, 98 HVN for 20 mm/min at 800 rpm, 106 HVN for 60 mm/min at 1600 rpm and 96 HVN for 80 mm/min at 1600 rpm. Furthermore, the coefficient of friction increased from 0.341 for base materials to a maximum of 0.635, 0.667, 0.604, and 0.646 for the same combination of speed and feed rate, respectively. The maximum change in percentage is 26% in hardness and 49% in wear coefficient. [ABSTRACT FROM AUTHOR]

In the present investigation, an Al-18Si-3.6Cu alloy was modified by cerium (Ce), heat treated (T6), and aged for 1, 3, 5, and 7 h at 210°C. The resulting microstructures revealed that the addition of Ce as a modifier changed the morphology of the primary Si from coarse with a sharp edge to spherical, large-acicular/needle-like eutectic Si into a fibrous state, and dendrites of the Al phase into round branches with less interface separation. After thermal ageing, the microstructure of the modified alloy revealed no change in the morphology of the primary Si phase. However, a considerable change in the eutectic Si phase and the formation of fine precipitates of Al2Cu and Al2CeSi intermetallics in the matrix. Hardness was found to be significantly higher in the modified and age-hardened alloys. A Pin-on-disc wear tester was used to investigate the dry sliding wear behavior of alloys at different loads (10, 20, 30, and 40 N) and 1.0 m/s sliding velocity. The results indicated that the wear rate in the modified alloy was lower than the base alloy. Furthermore, the modified alloy after 5 h age hardening demonstrated high wear resistance and improved wear bearing capacity compared to the 1, 3, and 7 h age hardened alloys. [ABSTRACT FROM AUTHOR]

Pressureless sintering was employed at 1400°C to synthesize Ti matrix composites (TMCs) reinforced with in -situ TiB and TiC reinforcements using TiB2 and B4C initial reinforcements. The microstructure and wear behavior of the synthesized composites were evaluated and compared and the results showed that B4C caused the formation of TiB-TiC in -situ hybrid reinforcements in the Ti matrix. Also, TiB was in the form of blades/needles and whiskers, and TiC was almost equiaxed. Moreover, the volume fraction of the in -situ formed reinforcement using B4C was much higher than that formed using TiB2. In addition, although the hardness of the B4C-synthesized composites was higher, the composite synthesized using 3 wt.% TiB2 exhibited the highest hardness (425 HV). The wear test results showed that the sample synthesized using 3 wt.% TiB2 showed the lowest wear rate at 50 N, mainly because of its higher hardness. The dominant wear mechanism in the samples synthesized using 3 wt.% B4C was abrasive and delamination at 50 N and 100 N, respectively while in the samples synthesized using 3 wt.% TiB2, a combination of delamination and adhesive wear and adhesive wear was ruling, respectively. [ABSTRACT FROM AUTHOR]

The current research work presents the synthesis and characterization of graphene-reinforced bimodal (Bi) AA7075 matrix composite by powder metallurgy route. The bimodal AA7075 alloy is optimized with micro (µ)- and nano (n)-crystalline grain morphologies in order to achieve better strength while retaining the vital minimal ductility. The effect of milling duration on grain size and particle uniformity is characterized by XRD and TEM. Density, hardness, compressive strength, and wear rate of bimodal composites are investigated. The addition of optimized 20% µAA7075 particles to nAA7075 particles provides the minimum necessary ductility in bimodal composites while increasing the interplanar space between the phase lattices. The use of graphene up to 0.75% enhanced wear resistance in comparison with the other compositions. The existence of both adhesive mechanisms and abrasive wear further reveals the plasticity of the bimodal composites, which are ideally suitable for engineering applications requiring greater strength and reliability. [ABSTRACT FROM AUTHOR]

Here Mo2FeB2 cermet coating was prepared on the surface of the furrow opener tip using plasma cladding. The microstructure, phase composition, microhardness and wear resistance of the coating were investigated to improve the wear resistance and to address the susceptibility to failure in the tillage process. Firstly, cladding current, cladding speed, powder delivery rate and cladding distance were set as the experimental parameters. The optimal combination of process parameters was obtained using orthogonal test: cladding current 80 A, cladding distance 10 mm and cladding speed 20 cm/min. Subsequently, the wear-resistant cladding coatings was prepared under the optimal conditions. The microstructure and phase composition of the cladding coatings were characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffractometer (XRD). The results revealed that excellent metallurgical bonding was achieved between the cladding coatings and the substrate. The microstructure consisted of square, butterfly, cross darts, dendritic structures as well as irregular long strips of hard phase along with network eutectic microstructure and iron-based bonding phase. The phase composition included Mo2FeB2, M3B2(M: Mo, Fe, Cr), (Cr, Fe)7C3, MoB, CrB, Fe2B and Fe-Cr solid solutions. The hardness and wear resistance of cladding coatings were characterized using microhardness tester and the reciprocating friction and wear tester. An outstanding decreasing trend in microhardness from the surface to the substrate was observed for the cladding coatings, indicating a smooth transition in stress between cladding coatings and the substrate. The average microhardness of the cladding coating reached 9618 MPa, which was 2.79 times higher than that of the furrow opener tip. The wear test showed that the average wear amount (19.20 mg) and the average friction coefficient (0.294) of the cladding coating were reduced by 52.9% and 42.4%, respectively, compared with the substrate. Wear tests under various loads revealed that the friction coefficient between the cladding coating and the substrate gradually decreased with the increasing load, yet overall remained lower than that of the substrate. The wear morphology of the cladding coating under different loads was found to be lighter compared to the substrate. This was attributed to the presence of terterine borides with the high hardness, which acted as a wear-resistant skeleton, accompanying with the eutectic microstructure and bonding. The Mo2FeB2 cladding coating exhibited improved anti-plowing and anti-falling properties, leading to better wear resistance when compared with grade 45 steel substrate. The soil tank test was conducted using self-made friction and wear testing machine. The average wear of the tip of the coated layer was reduced by 70.4% (4.60 g), compared with the conventional tip (15.54 g). Field test demonstrated that the average wear amount (34.34 g) of the coated furrow opener tip was only 43.4% of that of the conventional one (79.06 g) in real soil conditions. The wear morphology revealed that the presence of the coating was effectively resisted the soil wear. The original appearance of furrow opener tip was maintained after a long time of wear, thus demonstrating the exceptional wear resistance. The results of this study can provide theoretical reference and feasible technical solutions for improving the wear resistance of agricultural machinery's soil-engaging parts. [ABSTRACT FROM AUTHOR]

High entropy nitride (HEN) films of (TiZrHfNbTa)Nx were deposited by reactive DC magnetron sputtering, choosing 304 stainless steel and silicon wafers as the experimental substrates. The influence of nitrogen flow rate R N : N 2 /(N 2 +Ar) on the microstructure and properties of HEN films was investigated. The results showed that HEN films exhibit granular surface morphologies and internal characteristics of amorphous embedded FCC crystals, exhibiting a structure of amorphous at the lower R N (0, 2 %) and transforming to FCC crystals with preferred (111) orientation as R N increasing (6.5%–26 %), with the decrease of crystallinity and the alteration of preferred orientation from (111) to (200) at the further increase of R N at 40 %. The introduction of nitrogen led to significant improvements of film hardness (>23 GPa) and modulus (>270 GPa). When R N = 13 %, the hardness is up to 30.7 GPa, and the modulus is 340 GPa at R N = 6.5 %. The as-deposited films exhibited excellent wear resistance, and the wear rate (6.65✕10−6mm3/Nm) was the lowest when R N = 2 %. [ABSTRACT FROM AUTHOR]

This study investigates optimizing wear resistance, hardness, and thermal conductivity in copper diamond composites. Despite copper's exceptional thermal and electrical properties, maintaining wear resistance at high temperatures remains a challenge. We address this by incorporating diamond particles into copper matrices using powder metallurgy. Through Taguchi and ANOVA analyses, we examine SEM microstructure, and mechanical properties, with a focus on wear performance. Employing the desirability function in Minitab 17 for optimization, we identify an optimal parameter set: 3 % volume diamond, 68.18 N applied load, and 7500 m sliding distance. The resulting wear loss of 24.736 m3, with a desirability rating exceeding 99.6 %, promises practical applications in wear-critical industries like aerospace and automotive. [ABSTRACT FROM AUTHOR]

The results of studies of the influence of Y as a reactive element on the properties of TiAlN coatings obtained by the method of vacuum-arc deposition are given. Changes in the structure and properties were analyzed using SEM in combination with EDX, XRD, indentation analysis and wear analysis. It is shown that the presence of Y changes the crystalline phase of the Ti0.6Al0.34Y0.06N coating. It consists of a combination of a cubic NaCl structure (basic phase) and a wurtzite structure (additional phase). In addition, it leads to a small grain size (12 nm) and a nano-columnar structure. The high hardness is partly the result of solution hardening due to the inclusion of larger Y atoms in the TiAlN lattice at the locations of the metal atoms. The reduced grain size of 12 nm also helps to increase the hardness of the coating. The hardness is 31 ± 2.5 GPa, the modulus of elasticity is 394.8 ± 35.8 GPa. The residual stress is approximately three times (-3352 ± 64 MPa) higher than the TiAlN coating (-720 MPa). In addition, a high level of compressive stress contributes to an increase in hardness, since defects responsible for their own compressive stress are an obstacle to dislocation movement. The improved hardness of the experimental coating can be explained by a triple effect: solution strengthening, grain grinding and high residual compressive stress. The addition of Y indicates a slower growth of the oxide layer on the surface of the coating during the wear test. After the addition of Y, Y ions preferentially separate at the grain boundaries and therefore effectively delay the inward diffusion of oxygen. The addition of Y promotes the formation of dense Al2O3, which is effective in restraining diffusion and therefore protects the coating from oxidative wear. [ABSTRACT FROM AUTHOR]

As-received (AsRec) EN24 steel was treated with conventional heat treatment (ConHeatTreat) without tempering followed by deep cryogenic treatment (DeepCryoTreat) as a supplemental treatment to study its tribological behaviour against alumina without or with mineral oil (MO) under different normal loads of 1 N and 5 N. The ConHeatTreat of the AsRec-EN24 obtained an 218.5% improvement in its hardness as the supplemental DeepCryoTreat of the ConHeatTreat-EN24 resulted in a 11.7% further improvement in its hardness. As a result, the ConHeatTreat-EN24 had the 67.5% and 56.3% lower wear volumes for 1 N and 5 N under dry condition and the 53.6% lower wear volume for 5 N under MO lubrication condition compared to those of the AsRec-EN24, respectively. The DeepCryoTreat-EN24 had the 11.5% and 39.7% lower wear volumes for 1 N and 5 N under dry condition and the unmeasurable wear volume for 5 N under MO lubrication condition compared to those of the ConHeatTreat-EN24, respectively. It could be concluded that the supplemental DeepCryoTreat further improved the hardness and thereby the abrasive wear resistance of the ConHeatTreat-EN24 under both dry and lubrication conditions. [ABSTRACT FROM AUTHOR]

This paper offers a comprehensive review and experimental investigation into Zinc-Aluminum (ZA) and Aluminum-Zinc alloys, focusing on their mechanical and tribological properties. Zinc-based alloys like ZA27, ZA12, and ZA8 are esteemed for their superior bearing qualities, with ZA27specifically noted for its strength and widespread use in wear-resistant applications such as plain bearings and bushings. Despite surpassing materials like brass, bronze, and steel bearings, ZA alloys are constrained by their operational temperature limits above 100°C and exhibit lower ductility and impact resistance, potentially leading to dimensional instability. Enhancements via alloying elements (Cu, Mn, Mg, Ni, Si, Ti, Zr, Sr, Sc, Eu, Ag), heat treatment, and increasing aluminum content are identified strategies. The literature indicates that Al-25Zn has mechanical and tribological properties comparable to ZA27, although direct comparative experimental data are scarce. In this experimental investigation, aluminum, zinc, ZA27, and Al-25Zn alloys were fabricated using stir casting, and their properties were examined. Results show that the Al-25Zn alloy possesses the highest hardness, tensile strength, and wear resistance, as well as the lowest coefficient of friction (COF) among the materials tested. The Al-25Zn alloy offers higher elongation and similar thermal constraints, making it ideal for applications needing strong mechanical performance and low friction coefficients.

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.