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An efficient method to accelerate the use of polymer composites is to focus on their development as environmentally friendly materials that can naturally break down without causing any harm to the ecosystem. Hence, the primary aim of this study is to develop a biocomposite material through the fusion of Sesbania rostrata (SRF) bark fibers and the polycaprolactone (PCL) biopolymer. Various percentages (10, 15, 20, and 25 wt.%) of untreated and sodium bicarbonate‐treated SRF were incorporated into polycaprolactone to create the biocomposite samples. The composite panels were made using the compressing molding technique. Several tests were performed on the samples, such as mechanical, thermal, water absorption, wear, and morphological tests. Research has demonstrated that the strength of biocomposites composed of 20% chemically treated SRF and PCL is superior to that of other mixed materials. The thermal properties of the biocomposite remained unchanged when untreated fibers were included, but they improved when treated fibers were included. Higher water absorption properties are attributed to an increased fiber volume fraction in the biocomposites, while chemically treated fibers exhibit a notable improvement in water resistance. The wear test results indicate that the weight loss of the biocomposites is mainly influenced by the contact temperature and adhesion between the SRF surface and the PCL matrix. When examining the fractured biocomposites with a scanning electron microscope (SEM), it becomes evident that the primary reasons for failure are fiber pull‐out, debonding, and agglomeration. Highlights: SR Natural fiber is chemically treated by eco‐friendly sodium bicarbonate.The treated SRF‐reinforced composites had best mechanical property.The treated SRF‐reinforced composites showed less water absorption.The composite mechanical and thermal properties had dropdown at 25 wt.% SRF.The addition of SRF reduced the weight loss of composites on wear test. [ABSTRACT FROM AUTHOR]

Pins and jacks play an important role in the transmission capability and reliability of electrical connectors. Their surface coating is especially vulnerable under mechanical friction or varying temperature condition. In this work, the repetitive mechanical insertion and withdrawal experiments are conducted with the use of self-designed test rig. The wear and corrosion behaviors of circular electrical connectors are experimentally investigated under mechanical operations at temperature ranging from 25 to 120 °C. The variations in contact resistance and force observed in the mechanical wear tests are recorded and interpreted explicitly. The effect of temperature on the insertion characteristic curve is compared and analyzed. Based on the variation in contact resistance and force, surface morphology and element analysis, the degradation mechanisms of connectors under different temperatures are illustrated explicitly. The mechanical lifetime of connectors is approximately 12,500, 15,000 and 8500 at 25, 60 and 120 °C, respectively. The results show the temperature stress has a substantial influence on the wear and corrosion behavior of electrical contact interface. [ABSTRACT FROM AUTHOR]

Extended-reach drilling represents an advanced way of drilling and accessing reservoirs that were previously economically not feasible to drain, impossible to reach or in an environmentally sensitive area. One of the main issues that appears while drilling such wells is caused by the high values of friction factor which cause high values of torque and drag. One of the suggested solutions is to use a protective sliding ring made from materials such as POM, Teflon and PA6 in combination with lubricants added to a polymer mud system. First, measurements were conducted on a lubricity tester to choose the best material and, after finishing, a mechanical wear test was conducted on a specially designed device to measure mechanical wear. Results showed that Teflon showed lower values of friction factor in comparison to steel and the mechanical wear was minimal. The lowest value of friction force was recorded for blocks made from Teflon in tested mud systems. It is also noticeable that, in polymer mud with weighting additives and lubricant, the value of the friction force is higher than in polymer mud with lubricant only. [ABSTRACT FROM AUTHOR]

Fabrication of aluminium (Al) composites by stir casting process is an effective method for fabrication of better quality of Metal Matrix Composites (MMCs). Stir casting technique is one of the most commonly accepted techniques. In this research work, al7075 / SiC+CeO2 hybrid MMCs have been fabricated with varying wt.% of SiC (2%, 4%, 6% and 8%) particulates and constant 5% of CeO2 particulates. The ascast alloy and hybrid composite were hot rolled at a temperature of 500°C. Whereas, both the ascast and hot rolled hybrid composite was subjected to micro-structural, mechanical and wear tests. Optical microscope analysis revealed uniform dispersal of hard particles with in the base matrix in case of both of ascast and hot rolled composites. Hot rolled MMCs showed enhancement of 22.64% of hardness when compared with ascast alloy with increasing reinforcement of 0-6 wt.% of SiC content. Tensile strength increases by 28.24% for hot rolled composites when compared to the as cast and other hybrid composites. Reduction of wear loss by 54.38% for hot rolled composites when compared to the as cast and other hybrid composites. A tensile and wear fractography result shows the internal fractured structure which was analysed using a SEM analysis. [ABSTRACT FROM AUTHOR]

Particle-induced osteolysis resulting from polyethylene wear remains a source of implant failure in anatomic total shoulder designs. Modern polyethylene components are irradiated in an oxygen-free environment to induce cross-linking, but reducing the resulting free radicals with melting or heat annealing can compromise the component's mechanical properties. Vitamin E has been introduced as an adjuvant to thermal treatments. Anatomic shoulder arthroplasty models with a ceramic head component have demonstrated that vitamin E–enhanced polyethylene show improved wear compared with highly cross-linked polyethylene (HXLPE). This study aimed to assess the biomechanical wear properties and particle size characteristics of a novel vitamin E–enhanced highly cross-linked polyethylene (VEXPE) glenoid compared to a conventional ultrahigh-molecular-weight polyethylene (UHMWPE) glenoid against a cobalt chromium molybdenum (CoCrMo) head component. Biomechanical wear testing was performed to compare the VEXPE glenoid to UHMWPE glenoid with regard to pristine polyethylene wear and abrasive endurance against a polished CoCrMo alloy humeral head in an anatomic shoulder wear-simulation model. Cumulative mass loss (milligrams) was recorded, and wear rate calculated (milligrams per megacycle [Mc]). Under pristine wear conditions, particle analysis was performed, and functional biologic activity (FBA) was calculated to estimate particle debris osteolytic potential. In addition, 95% confidence intervals for all testing conditions were calculated. The average pristine wear rate was statistically significantly lower for the VEXPE glenoid compared with the HXLPE glenoid (0.81 ± 0.64 mg/Mc vs. 7.00 ± 0.45 mg/Mc) (P <.05). Under abrasive wear conditions, the VEXPE glenoid had a statistically significant lower average wear rate compared with the UHMWPE glenoid comparator device (18.93 ± 5.80 mg/Mc vs. 40.47 ± 2.63 mg/Mc) (P <.05). The VEXPE glenoid demonstrated a statistically significant improvement in FBA compared with the HXLPE glenoid (0.21 ± 0.21 vs. 1.54 ± 0.49 (P <.05). A new anatomic glenoid component with VEXPE demonstrated significantly improved pristine and abrasive wear properties with lower osteolytic particle debris potential compared with a conventional UHMWPE glenoid component. Vitamin E–enhanced polyethylene shows early promise in shoulder arthroplasty components. Long-term clinical and radiographic investigation needs to be performed to verify if these biomechanical wear properties translate to diminished long-term wear, osteolysis, and loosening. [ABSTRACT FROM AUTHOR]

Composite coatings on the surface of a semi-continuous cast 7005 aluminum alloy under different aging treatments (T6, RRA, and FSA) are presented and characterized in this research. SiO2 combined with stearic acid (STA) modified by KH550 was utilized to achieve multifunctional superhydrophobic coatings. Adhesive tape adhesion, blade scratch, and mechanical wear tests were utilized to assess the durability of the superhydrophobic coatings. The results showed that the prepared coatings exhibited excellent superhydrophobicity, self-cleaning ability, and mechanical properties, especially the T6 temper alloy. This alloy had the largest CA value (156.5°) and the lowest SA value (4.3°). The composite coatings still exhibited excellent superhydrophobicity under mechanical damage. Furthermore, the alloys with STA/SiO2 displayed marvelous corrosion resistance efficiency. The T6 temper alloy with a protection rate of 73.8% had an approximately one-order-of-magnitude decrement in carrion current density. The composite coating can be effectively utilized in various industrial fields, thus extending its potential impact. [ABSTRACT FROM AUTHOR]

Egg shells and fish scales are two abundantly available by-products from food industries which can be used as filler materials to reinforce polymer composites. The bulk of discarded chicken eggshells and fish scales are disposed of in landfills, which cause environmental issues. The present research work focuses on the water absorption, mechanical and tribological properties of epoxy composites reinforced with chicken eggshells and catla fish scale particles. Hybrid composites incorporating both fillers were also made and evaluated. Results from the water absorption tests showed that the addition of fillers decreased the water absorption of the composites than neat epoxy. Tensile and impact tests revealed that the inclusion of fillers reduced the tensile and impact strength of the composites compared to neat epoxy, but improved the tensile modulus. The hybrid composite (EFREC) showed improvement in both flexural strength and modulus in comparison to neat epoxy. Also, the results from the wear tests revealed that the addition of fillers improved the wear resistance of the composites. Among all the mechanical and wear tested composite specimens, the hybrid composite (EFREC) showed the best performance. This was also validated from the SEM images of the fracture and wear surfaces of the composites. [ABSTRACT FROM AUTHOR]

In the current study, graphite was exfoliated using a Hummer's technique to produce graphene oxide (GO), which was then reduced with hydrazine hydrate (a reducing agent) to produce reduced graphene oxide (rGO) with high purity. The XRD, FT-IR, SEM, and TGA analysis confirmed the synthesis of rGO by stating its crystal phase, chemical functional group, morphology, and thermal stability. The objective of this study is twofold: firstly, to synthesize the reduced graphene oxide (rGO) cost-effectively, and secondly, to explore its potential as an additional filler in Glass Fiber Reinforced Polymer (GFRP) composites. Aiming to enhance their overall performance. The GFRP laminate composite was fabricated through the hand layup technique by varying the concentration of Gr (i.e., 0.5 wt% & 1 wt%) and rGO (i.e., 0.5 wt% & 1 wt%). The morphological study of the fracture surface revealed a proper dispersion of filler obtained at 0.5 wt% and by increasing the concentration to 1 wt% it reveals a clustering of fillers and formation of micro-voids. The result revealed that maximum improvement has been observed in the GFRP composite having 0.5 wt% rGO composite than neat GFRP composite. Incorporation of rGO micro-filler in GFRP laminate composite significantly improved the tensile strength, flexural strength, and in their modulus by 59.56%, 18.21%, 24.45%, and 22.75% respectively compared to neat GFRP laminate composite. In the case of 0.5 wt% graphite filler demonstrates an enhancement in tensile strength, flexural strength, and their modulus by 37.98%, ∼8%, 6.64%, and ∼5% respectively. In fretting wear test reveals that 1 wt% of graphite filler has better wear resistance than all other composites. The worn morphology revealed adhesive and abrasive wear as the predominant wear mechanism. The incorporation of rGO filler in GFRP makes it a promising material for industrial applications that demand high strength and superior wear resistance. [ABSTRACT FROM AUTHOR]

Gravity sensing is a valuable technique used for several applications, including fundamental physics, civil engineering, metrology, geology, and resource exploration. While classical gravimeters have proven useful, they face limitations, such as mechanical wear on the test masses, resulting in drift, and limited measurement speeds, hindering their use for long-term monitoring, as well as the need to average out microseismic vibrations, limiting their speed of data acquisition. Emerging sensors based on atom interferometry for gravity measurements could offer promising solutions to these limitations, and are currently advancing towards portable devices for real-world applications. This article provides a brief state-of-the-art review of portable atom interferometry-based quantum sensors and provides a perspective on routes towards improved sensors. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the impact of beam deflection geometry on the structure, surface architecture, and friction coefficient of electron-beam-modified TC4 titanium alloys. During the experiments, the electron beam was deflected in the form of different scanning geometries, namely linear, circular, and matrix. The structure of the treated specimens was investigated in terms of their phase composition by employing X-ray diffraction experiments. The microstructure was studied by scanning electron microscopy (SEM). The surface architecture was examined by atomic force microscopy (AFM). The friction coefficient was studied by a mechanical wear test. It was found that the linear and circular deflection geometries lead to a transformation of the phase composition, from double-phase α + β to α' martensitic structure. The application of a linear manner of scanning leads to a residual amount of beta phase. The use of a matrix does not tend to structural changes on the surface of the TC4 alloy. In the case of linear geometry, the thickness of the modified zone is more than 800 μm while, in the case of EBSM using circular scanning, the thickness is about 160 μm. The electron-beam surface modification leads to a decrease in the surface roughness to about 27 nm in EBSM with linear deflection geometry and 31 nm in circular deflection geometry, compared to that of the pure TC4 substrate (about 160 nm). The electron-beam surface modification of the TC4 alloy leads to a decrease in the coefficient of friction (COF), with the lowest COF values obtained in the case of linear deflection geometry (0.32). The results obtained in this study show that beam deflection geometry has a significant effect on the surface roughness and friction coefficient of the treated surfaces. It was found that the application of a linear manner of scanning leads to the formation of a surface with the lowest roughness and friction coefficient. [ABSTRACT FROM AUTHOR]

Metal Matrix Composites (MMCs) are employed in high-strength industrial applications due to their strength-to-weight ratio and temperature tolerance. The specimens' tensile strength, impact strength, shear strength, hardness, and wear rate were tested utilizing Magnesium as the matrix and Graphene nanoplatelets (GNPs) as reinforcement. Studying fly ash. Here, the tests are structured with changing weight fractions of the matrix (Magnesium (Mg)), graphene, and fly ash (for MMC 1: Mg: 100% + GNPs: 0% + fly ash: 0%; for MMC 2: Mg: 93.7% + GNPs: 0.3% + fly ash: 6%; and for MMC 3: Mg: 93.6% + GNPs: 0.4% + fly ash: 6%). Experimental results showed that MMC 3 has a higher tensile strength, shear strength, impact strength, and hardness (RHN) than other materials and a lower warping. Granite dust was employed in Al6082 mechanical and wear testing. This research studied the mechanical properties and wear rate of two granite dust compositions, 0.5% and 1.0%. Al6082/granite dust wear rate depends on applied stress, sliding distance, sliding velocity, and composite weight% with reinforcement. The input parameters for Al6082 / granite dust enhanced the abrasion resistance of Aluminum alloys, and this granite dust-reinforced material may be used in engineering applications demanding low strength and weight. Al6082/granite dust wears faster than MMC. Al6082/granite dust has less strength than MMC. [ABSTRACT FROM AUTHOR]

In the present study, comparative analysis of glass ionomer and nanofillers in the performance of dental composite has been reviewed. In dental composite, a number of particulate fillers specifically nanoparticle are being tested and used. A new approach has been tried and investigated to replace expensive nanofillers with the other filler such as glass ionomer. There is a strong need to understand the scientific method, to conduct the clinical trial, and to perform the laboratory test to evaluate role of each parameter, constituent in the performance of dental composite. The present research reviewed the recent finding, possible opportunity and challenges for use of glass ionomer as replacement of nanofiller in dental composite. The existing literature on the favorable and non‐favorable side of glass ionomer is critically evaluated. The major aspect considered in the present review was to evaluate the surface roughness, mechanical properties and wear properties. The present article attempted to provide a state‐ of‐ the‐art analysis of fabrication method, surface treatment method and comparative analysis on role of particulate filler versus glass ionomer on the performance based on mechanical and wear testing mechanism. [ABSTRACT FROM AUTHOR]

In carbon nanotube (CNT) reinforced metal-matrix composites, a strong interface between CNTs and the matrix is essential for an effective load transfer. Otherwise, the excellent qualities of CNTs would virtually remain unexploited. The aim of this study is to investigate the effect of Al 4 C 3 formation on the mechanical properties of CNT/Al composites. Composite powders were produced through a three-stage process; First, CNTs were sufficiently crushed via high-energy milling of 20 h. Then, the crushed CNTs were ultrasonically mixed with raw CNTs (in an ethanol medium) followed by a wet milling process. Finally, different amounts of the obtained reinforcing agent (0.5, 1, 1.5, 2, and 3 wt%) were milled with aluminum powders. Composite powders were subsequently consolidated using spark plasma sintering (SPS) process at two different temperatures (500 and 550 °C) For each sample, the amount of carbide was calculated in a semi-quantitative manner using Raman spectroscopy. The results of phase analysis and mechanical-behavior evaluations showed that Al 4 C 3 formation, due to the consumption of highly-activated crushed CNTs, could improve the interface bonding state while maintaining CNTs structural integrity. Moreover, mechanical and wear tests revealed that the optimum properties were obtained for the composite reinforced by 1 wt% processed carbon nanotubes (PCNTs) and SPSed at 550 °C for 10 min. These findings can open up a window toward the realm of design and processing of CNT/Al composites. [ABSTRACT FROM AUTHOR]

This study was performed to expand the usage area of phenylene sulfide (PSS) by reducing its cost without deteriorating the material properties. For this purpose, mechanical, thermo‐mechanical and abrasion tests were conducted to composite materials obtained by adding carbon fiber (CF), basalt fiber (BF), zeolite, and bentonite into PPS, and the effects of additive type and ratio were examined. For the test samples, fabricated by the melt blending, the fiber content was 10 wt.%, while zeolite, and bentonite ratios were 1, 5, and 10 wt.%. According to tensile and abrasion test results, zeolite, and bentonite improved the properties of fiber‐reinforced PPS by showing a synergistic effect. It has been demonstrated in this research that the cost of fiber‐reinforced PPS matrix composites, which are widely used in advanced engineering applications, can be reduced by using natural minerals zeolite and bentonite without sacrificing material properties. Findings obtained from mechanical and wear tests, revealed that the composition containing 10, 10, and 80 wt.%, zeolite, CF, and PPS, respectively, exhibited optimum material properties. BF for PPS has been shown to be an alternative reinforcement to CF, as it exhibits the lowest wear rate and better interacts with particles in the matrix. [ABSTRACT FROM AUTHOR]

The applications projected in the coatings are in implants with the lower extremities since they require a great load capacity and are essential for walking. Therefore, the use of devices or implants is necessary for recovery, osteosynthesis, and fixation. The tribocorrosive behavior of nanostructured compounds based on titanium oxide with an intermediate layer of gold deposited on titanium substrates was determined. These coatings were obtained using the reactive magnetron sputtering technique. Tribocorrosive properties were evaluated at sliding speeds of 3500 mm/min, 4500 mm/min, 6000 mm/min, 7500 mm/min, and 9000 mm/min with loads of 1 N, 2 N, 3 N, 4 N, and 5 N. The coatings were characterized by X-ray photoemission spectroscopy and X-ray diffraction, and the surface roughness was analyzed by atomic force microscopy. The dual mechanical and electrochemical wear tests were carried out with a potentiostat coupled to a pin on the disk system. The system was in contact with a hanks solution (37 °C), which acted as a lubricant. Structural characterization made it possible to identify the TiO2 compound. In the morphological characterization, it was found that the substrate influenced the surface properties of the coatings. The tribological behavior estimated by the wear rates showed less wear at higher load and sliding speeds. It was shown that it is possible to obtain coatings with better electrochemical and tribological performance by controlling the applied load and slip speed variables. In this study, a significant decrease corresponding to 64% was obtained, specifically in the speed of deterioration, and especially for a load of 5 N, depending on the sliding speed that went from 0.2831 mpy (Mils penetration per year) to 3500 mm/min compared to 0.1045 mpy at 9000 mm/min, which is explained by the mechanical blockage induced by the coating. [ABSTRACT FROM AUTHOR]

The present work aims to develop Cu/ZrO2 surface composite by friction stir processing and analyse the effect of zirconia incorporation on microstructure, mechanical, and tribological behaviour of developed copper matrix composite. Microstructural observations indicated that grains were equiaxed and fine in the stir zone of the composite and zirconia particles were uniformly dispersed in the copper matrix with excellent bonding. The test results for mechanical and wear behaviour showed increment in hardness and wear resistance as compared to copper which may be because of the effect of zirconia presence and grain refinement. The fabricated composite displayed higher value of average friction coefficient in comparison to as received copper. The worn surface observed by SEM revealed the predominance of adhesion and delamination wear mechanism in base copper. [ABSTRACT FROM AUTHOR]

Monel 400 alloy is widely employed in marine engineering equipment due to its excellent corrosion resistance, high strength and toughness. In this paper, the tribo-corrosion behavior of Monel 400 alloy in seawater under different rotational velocities was investigated by a pin-disk tribometer with an integrated electrochemical cell. The results revealed that the material loss rate and friction coefficient of the Monel 400 alloy, after tribo-corrosion and mechanical wear tests, increased with increasing rotational velocity. Under mechanical-wear conditions, the material loss rate increased with the sliding distance extension at higher velocities, and then more serious crack nucleation and propagation occurred at the subsurface. Under tribo-corrosion conditions, when the rotational velocities increased from 0.125 m/s to 0.5 m/s, the thickness of the corrosion product's layer was reduced from 50 nm to 30 nm; that is, the lubrication of the corrosion product became worse. As a result, the material-loss rate and friction coefficient increased significantly at the velocity of 0.5 m/s. Importantly, the antagonistic effect, rather than the synergistic effect, between corrosion and mechanical wear, has been verified for the tribo-corrosion of Monel 400 alloy in seawater, and the mechanism was analyzed. [ABSTRACT FROM AUTHOR]

Additive technologies provide a means for repair of various failure modes associated with material degradation occurring during use in aggressive environments. Possible repair strategies for AISI 4340 steel using AISI 316L deposited by additive friction stir deposition (AFSD) were evaluated under this research by metallography, microhardness, and wear and mechanical testing. Two repair geometries were investigated: groove-filling and surface cladding. The former represents repair of localized grinding to eliminate cracks, while the latter represents material replacement over a larger area, for example, to repair general corrosion or wear. The 316L deposited by AFSD exhibited a refined microstructure with decreased grain size and plastic strain, ~ 12% lower strength, and 5–12% lower hardness than the as-received feedstock. Wear testing by both two-body abrasion and erosion by particle impingement indicated that the wear resistance of the 316L cladding was as good as, or better than, the substrate 4340 material; however, there was some evidence that the resistance to intergranular corrosion was compromised due to the formation of carbides or sigma phase. In both repair geometries, the microstructure of the substrate beneath the deposited material exhibited heat affected zones where the substrate appeared to have austenized to a depth of ~ 4 mm during the deposition process, and transformed to martensite or bainite during cooling. This report constitutes an initial evaluation of a novel approach to the repair of structural steel components damaged by microcracking, wear, or corrosion, with potentially broad applicability to the marine, aerospace, and heavy duty off-road industries. [ABSTRACT FROM AUTHOR]

The reinforcement of natural fibre and fillers in polymer resin is the latest trend followed by research groups and industries for the development of sustainable composites. Basalt fibre and waste marble powder are naturally occurring substances used to enhanced polymer properties. The present research examined the effect of both basalt fibre and waste marble powder in epoxy resin. The hand lay-up method was employed to fabricate the composite and test for mechanical and wear behaviour. The tensile, flexural, and impact energy were enhanced up to 7.5 wt. % of WMP, and the Vickers hardness of epoxy enhanced every state of reinforcement of WMP. The specific wear rate was observed to be increased with the addition of WMP until 7.5 wt. %. Scanning electron microscopy was performed to examine the nature of fractured surface wear phenomena. [ABSTRACT FROM AUTHOR]

Effect of zirconium additions on the microstructure, phase composition, microhardness and wear resistance of high-entropy AlCoCrCuFe alloys with equal mole fractions of the components is studied. The methods of x-ray diffraction, optical and electron microscopy and mechanical wear tests are used for the metallographic study. Zirconium additions are shown to affect positively the hardness, strength and wear resistance of the AlCoCrCuFeZr alloy due to refinement of grains, solid-solution hardening and changes in the phase composition. [ABSTRACT FROM AUTHOR]

The effects of the squeeze casting process on the microstructure, mechanical properties and wear characteristics of hypereutectic Al–Si–Cu–Mg alloys have been investigated by optical, scanning and transmission electron microscopy and mechanical property test; the wear behaviour was investigated using a pin-on-disc configuration; alloy ingots were prepared by gravity casting, liquid squeeze casting and semisolid squeeze casting. The results show that the Si phase was refined and the α-Al dendrites transformed to rosette grains after semisolid squeeze casting. The peak intensity of the second phase decreased after extrusion, indicating that extrusion promotes the dissolution of solute elements into the matrix. Among the three casting processes, the alloys formed by semisolid squeeze casting had the best mechanical properties. Tensile strength, elongation and Brinell hardness reached 187.67 MPa, 2.33% and 142.5 HB, respectively. After semisolid squeeze casting, the morphology of the wear surface was flat and the number of spalling pits and furrows is less. Meanwhile, the friction coefficient and wear loss of the alloy sample are minima. Due to the uniform distribution of Si phases and equiaxed crystallization of α-Al phase in semisolid squeeze casting Al–Si–Cu–Mg alloys, the wear resistance is markedly enhanced. [ABSTRACT FROM AUTHOR]

We study the problem of insufficiently detailed description of the requirements imposed by the state system for guaranteeing the uniformity of measurements in the Russian Federation on the developed and certified measurement methods used for the mechanical testing of various materials. We emphasize the urgency of the problem of compatibility of the requirements imposed on the metrological support of the results of quantitative chemical analyses and indirect results of mechanical testing for the wear resistance of materials in the process of their friction against fixed abrasives. To guarantee the accuracy of measurements of the characteristics of wear resistance of studied materials, we propose to use the grain size of the abrasive material and the frequency of rotation of the abrasive disc as variable factors. In order to establish the requirements to the metrological characteristics of the procedures of mechanical testing, in particular, in finding the relative wear resistance of materials, we justified the conditions required for precision measurements. We also present the results of multistage experiments aimed at testing materials for wear resistance performed with the use of various investigated and consumable materials, measuring instruments, and testing equipment. We also propose and justify the conditions of planning experiments in the case of determination of the other relative mechanical characteristics of the studied materials with an aim to establish precision indicators in the development of methods of mechanical testing for abrasive wear. The application of the accumulated results would enable the developers of the methods for mechanical testing to establish the metrological characteristics of materials in agreement with all requirements of the State System for Ensuring the Uniformity of Measurements of the Russian Federation. [ABSTRACT FROM AUTHOR]

In the present work, the influence of alloying elements, on the mechanical characteristics and wear behavior by modification of the chemical composition of the ductile iron was studied, to improve these characteristics for the manufacture of agricultural tractors parts in particular front and rear axles, ploughshares, gear crankcase, pinions, transmission shafts, crankshafts, etc... The cast iron investigated was prepared in an induction furnace at 1500°C and inoculated by a ferro-silicon-magnesium to 45% Si and 10% Mg. The specimens were casted into self-hardening sand moulds at 1450°C, after an addition of alloying elements, Manganese (0.6%), Nickel (0.5%), Molybdenum (0.2%), and Vanadium(0.1%) in the base spheroidal graphite cast iron produced. Various techniques including, optical microscopy, microhardness, hardness, tensile strength, impact resistance, and wear tests (wear resistance and friction coefficient) were used to characterize these specimens. The obtained results show that the tested samples have ductile iron structures formed by ferrite and pearlite. Moreover, mechanical and wear tests prove that the alloyed cast iron has improved characteristics compared to unalloyed cast iron and shows the positive effect of alloying elements on these characteristics. [ABSTRACT FROM AUTHOR]

In the present research, an effect of nanographite and zirconium oxide (ZrO2) dual reinforcement addition on the mechanical and wear behaviour of Al7075 alloy has been studied. The Al7075 alloy with constant 3 wt.% of graphite particles and varying (3 and 6) weight percentages of ZrO2 particle-reinforced hybrid composites were fabricated by stir casting method. The synthesized dual particle-reinforced Al7075 alloy hybrid composites were subjected to microstructural studies, mechanical and wear properties testing. Microstructural characterizations of obtained samples were carried out by scanning electron microscopy. The graphite and ZrO2 particles were evenly distributed in the Al7075 alloy matrix. The hardness, impact and tensile strength of hybrid composites have been increased with the addition of dual reinforcements. There was slight decrease in the ductility of the Al7075 alloy after the incorporation of these reinforcements. The wear behaviour of the prepared samples was tested at varying loads and speeds. The hybrid composites exhibited a superior wear resistance as compared to base matrix alloy Al7075. Various fracture and wear mechanisms were observed in the Al7075 alloy with graphite and ZrO2 particle-reinforced composites using SEM. [ABSTRACT FROM AUTHOR]

The effect of heat treatment with an addition of titania on the phase development and mechanical properties of sand casted Al-SiC-TiO2 metal matrix composite was investigated. The standard samples dimensions for tensile properties, wear and hardness were prepared. These samples were heat treated at different temperature of 180°C to 220°C without solution treatment. The samples were held at the heat treatment temperature for an hour after which they were allowed to cool in the air. Thereafter, samples were subjected to various mechanical and wear tests, respectively. The phases evolved due to heat treatment of the samples were examined using X-ray diffractometry. It was observed that the increase in heat treatment temperature of samples leads to the formation of precipitates within the aluminium matrix composite reinforced with SiC. The addition of 5 % titania inhibits the formation of aluminium silicon carbide phases in preference to SiO2 and TiO2. The increase in heat treatment temperature leads to the formation of precipitates like TiSi2, Si11.4TiO24.4, TiC, Al2O3 and buckminsterfullerene C70 within the aluminium matrix composite. The addition of 10 % titania leads to the development of precipitates like Al5Ti3 and Ti-rich oxides with the aluminium matrix. At 220°C, alumina was formed within the metal aluminium matrix and no trace of SiC was found. All the samples have low wear loss but the heat treated at 180°C sample (A) has the lowest wear loss. The heat treatment of the sample without solution treatment has impact on the phase development in the samples. It gives rise to the development of precipitates in the samples which affects the hardness and other mechanical properties. The addition of SiC and TiO2 to aluminium matrix makes the sample harden. Sample A heat treated at 200°C have the highest hardness. [ABSTRACT FROM AUTHOR]

The current study focuses on the development of silanized graphene oxide reinforced basalt fiber/epoxy composites for enhanced tribological and viscoelastic properties. The modified-graphene oxide nanoplatelets were characterized using energy-dispersive X-ray spectroscopy, and Raman analyses. Pin-on-disk wear test and dynamic mechanical thermal analysis were conducted to determine the tribological and viscoelastic properties of the fabricated specimens with different silanized-graphene oxide loadings in the matrix (0–0.5 wt.% at a step of 0.1). The multiscale specimens were fabricated using the hand lay-up technique. The best silanized-graphene oxide loading for effectively enhancing the tribological properties was found to be 0.4 wt.%, whose wear rate and friction coefficient were 62% and 44%, respectively lower than those of the neat basalt/epoxy composite. The examination of the worn surfaces showed the enhanced basalt fiber/epoxy bonding in graphene oxide-reinforced specimen. From the results of dynamic mechanical thermal analysis, the specimen filled with 0.4 wt.% silanized-graphene oxide demonstrated the highest increase of 130% and 13.6℃ in the storage modulus and glass transition temperature as compared to the neat composite. This study indicated that the addition of silanized-graphene oxide considerably enhanced the tribological and viscoelastic properties of the fibrous composites. [ABSTRACT FROM AUTHOR]

• Uniform TiO 2 was coated on mesh membranes via a facile biomineralization approach. • The coated-mesh showed superhydrophilicity and underwater superoleophobicity. • The coated mesh separated oil/water mixtures efficiently with anti-fouling ability. • The coated mesh had great chemical, thermal and mechanical durability. In this work, a novel and facile method was used to coat a uniform and conformal TiO 2 film on a stainless steel mesh via polyethylenimine-catalyzed biomineralization of titanium bis(ammonium lactato)dihydroxide at neutral pH, ambient temperature and pressure. The fabricated mesh showed excellent superhydrophilicity and underwater superoleophobicity. It separated immiscible oil/water mixtures by gravity at a high flux (∼3 × 104 L m−2 h−1), high separation efficiency (∼99.999%), and exhibited excellent anti-oil-fouling ability. The mesh also demonstrated great durability: (1) it had outstanding stability in 1 M NaCl, 0.1 M HCl, 0.1 M NaOH solutions, and absolute ethanol; (2) it maintained underwater superoleophobicity in solutions of pH from 1 to 13 and saturated NaCl solutions; and (3) the separation efficiency was retained after high temperature treatment and mechanical wear tests (sonication, abrasion and crumpling). The biomineralization coating method was also applied on other substrates (nonwoven mesh, filter paper and PVDF membrane), which also showed good capability for oil/water separation. Therefore, this new environmentally benign approach of preparing superwetting surfaces provides a durable and sustainable solution to the treatment of oily wastewater. [ABSTRACT FROM AUTHOR]

Copyright of Tribologie und Schmierungstechnik is the property of Narr Francke Attempto Verlag GmbH & Co.KG and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tribologie und Schmierungstechnik is the property of Narr Francke Attempto Verlag GmbH & Co.KG and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract A series of CoCrFeNiCu x (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) high entropy alloys (HEA) were prepared using arc melting technique and the effect of Cu on microstructure evolution and wear was studied both at room and high temperature. Microstructure reveals two phases, namely, CoCrFeNi and pure Cu. Wear rate at room temperature (RT) as well as at elevated temperatures (ET) decreases with increase in Cu content. However, wear resistance is found to be more at ET than RT. This is attributed to the self-lubricating behaviour of Cu at elevated temperature. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract Within the vibro-acoustic optimisation of complex components under dynamic loading the radiated sound power is commonly used as an objective. For this purpose, the frequency-dependent sound power has to be quantified by a single scalar objective. For the required steady state simulations the mode-based frequency spacing can include non-equidistant step sizes as well as can change due to structural or material modifications. Thus, the total number of frequency steps is depending on the number of contributing modes that can be changed during optimisation processes with structural or material modifications. Furthermore, the accuracy of the objective has to be assured by choosing the required number of frequency steps and avoiding either under-resolved peaks or too many frequency steps. In this study, we present an approach for the determination of the averaged sound power within the covered frequency range with non-equidistant spacing based on the power spectral density. These scalar quantities are robust to any model changes. Thereafter, the mean power is used as a convergence criterion to determine the number of required frequency steps for a single mode and thus to reduce the computational efforts to a minimum. Further, a recommendation for a common rule for the spacing of single mode is given. This results in the frequency spacing estimation depending on the distance of neighbouring modes as well as the damping and biasing. Moreover, the combination of robust scalar objectives and efficient frequency spacing opens the prospects of accessing sound power objectives for complex optimisation problems. [ABSTRACT FROM AUTHOR]

Abstract Current state-of-the-art engine oils tend to enhance micro-pitting damage in rolling contacts under certain operating conditions. ZDDP anti-wear additive was shown to promote such behavior. However, in order to optimize an engine oil formulation for rolling contacts, further studies are needed to assess engine oils in terms of micro-pitting and wear damage. This investigation studies the micro-pitting and wear performance of a number of engine oils for rolling contacts in a ball-on-disc configuration under conditions prevalent in crankshaft roller bearing applications. Based on the results it was concluded that an engine oil containing higher blend of PAO base oil compared to the oil mixture of Group III and PAO has a lower tendency towards micro-pitting and wear. Highlights • Engine oils were assessed based on micro-pitting and wear damages. • Higher blend of PAO oil improves the tendency towards micro-pitting and wear. • Lower additive concentration and lower viscosity reduce tendency towards micro-pitting but promote mild wear. • Micro-pitting and mild wear are the competing mechanisms. [ABSTRACT FROM AUTHOR]

Highlights • The sealing of adjacent double IGUs has little effect on the structure. • The structural deflection is the controlling factor for ECS glass facades. • Preloads on cables have a significant effect on the static and the dynamic behaviors of ECS glass facades. • The effects of glass panel thickness and cable diameter on the structure are relatively small. Abstract Embedded cable support (ECS) glass facades are increasingly used in architectures, due to their good-looking appearance. In order to study the static and the dynamic behaviors of ECS glass facades, static and dynamic loading tests are carried out. The structural deflections, the axial forces of cables, and the natural frequencies under various test conditions are measured. Two finite element (FE) models are established in ABAQUS and calibrated by the test data. A parametric study is conducted to discuss the effects of preload, glass panel thickness, and cable diameter on the static and the dynamic behaviors of ECS glass facades. The results show that the sealing of adjacent insulated glasses has little effect on the structure. The structural deflection is the controlling factor for ECS glass facades, while the Mises stresses on the glasses are fairly low. The discrepancy of the results obtained from the two FE models is small. Preloads on cables have a significant effect on the static and the dynamic behaviors of ECS glass facades, whereas the effects of glass panel thickness and cable diameter on the structure are relatively small. [ABSTRACT FROM AUTHOR]

Highlights • Large-scale fire test of a typical underground structure is carried out. • Real fire scenario of underground structures is considered. • Fire performance of the structure subjected to biaxial loading is investigated. Abstract Fire disasters occurring in underground structures generally result in severe damage. In order to investigate the fire performance of typical underground structures, a large-scale fire test on a three-span frame structure was carried out. The tested model was loaded both by vertical and horizontal earth pressures. The applied temperature history, representing the time-dependent fire load, was determined by simulations of fire scenarios in the underground structure with the help of the software FDS. The paper contains test results of the temperature of the air in the furnace, the concrete and the steel bars in the structural model, and the state of deformation of the model. Apparent phenomena, such as cracking and spalling, were observed throughout the whole testing process. The results show that a very dangerous situation of the underground structure exposed to fire may occur during the cooling process. Curling of the top slab was observed during the heating process. More attention in fire-resistance design must be paid to the columns. The fire test results are useful for validation of numerical models and for further fire-resistance research of underground structures. [ABSTRACT FROM AUTHOR]

Increasing performance of IC engines often leads to higher combustion temperatures causing premature failure of exhaust valves. This paper presents for the first time a tribological assessment of hollow head & sodium filled valves (HHSVs) produced using a new and novel manufacturing process. Tests were conducted on HHSVs using bespoke bench-top wear and fatigue apparatus and they survived defined durability tests. Compared to traditional solid valves; the highest temperature of the hollow stem & sodium filled valves decreased from 745 °C to 590 °C, the new design and manufacturing process did not adversely affect the classical wear mechanisms (e.g. oxidation accelerated adhesion) or the material loss magnitude, and the design of HHSVs gives a 16.1% reduction in mass. [ABSTRACT FROM AUTHOR]

In a high speed milling operation the cutting tool acts as a backbone of machining process, which requires timely replacement to avoid loss of costly workpiece or machine downtime. To this aim, prognostics is applied for predicting tool wear and estimating its life span to replace the cutting tool before failure. However, the life span of cutting tools varies between minutes or hours, therefore time is critical for tool condition monitoring. Moreover, complex nature of manufacturing process requires models that can accurately predict tool degradation and provide confidence for decisions. In this context, a data-driven connectionist approach is proposed for tool condition monitoring application. In brief, an ensemble of Summation Wavelet-Extreme Learning Machine models is proposed with incremental learning scheme. The proposed approach is validated on cutting force measurements data from Computer Numerical Control machine. Results clearly show the significance of our proposition. [ABSTRACT FROM AUTHOR]

The Heat Treatment of Metallic Materials in Modern Industry is a Special Issue of the journal I Materials i , which aims to publish original full-length articles and review papers on basic and applied research centered around the given topic, and thereby make the understanding of the metallurgical background of the contemporary state of heat treatment techniques used in the industrial branches in the 21st century. Finally, the papers on laser- or electron-beam surface treatments as well as the physical vapor deposition of thin films are of interest to the Editors of this Special Issue. The papers which explore the research and development works on bulk heat and cryogenic treatment of steel, aluminium, titanium, magnesium, or copper alloys are particularly welcome. [Extracted from the article]

Relative motion between the fuel rods and fuel assembly spacer grids can lead to excessive fuel rod wear and, in some cases, to fuel rod failure. Based on industry data, such grid-to-rod-fretting is a significant cause of fuel failures in U.S. pressurized water reactor power plants. Kanthal advanced powder metallurgy technology or APMT, an FeCrAl steel alloy, and a braided SiC fiber, Chemical Vapor Infiltration SiC matrix (SiC/SiC) cladding by General Atomics are possible alternatives to conventional fuel cladding in a nuclear reactor due to their favorable performance under accident conditions. Tests were performed to examine the reliability of the cladding candidates and a conventional cladding, Zircaloy-4, under dry fretting conditions at elevated temperature. The contact was simulated with a rectangular and a cylindrical specimen over a line contact area. Confocal scanning laser microscopy was used to obtain a 3D map of the surface, which was in turn used for wear and work rate calculations on the samples. The wear rate coefficient was used as a measure of the performance and wear under fretting. Additionally, Energy Dispersive Spectroscopy was performed to qualitatively describe the microchemical changes the material undergoes during fretting. While APMT steel and SiC/SiC can perform favorably in loss of coolant accident scenarios, they also need to perform well when compared to Zircaloy-4 with respect to fretting wear. Wear coefficient measurements showed that APMT steel performs favorably in comparison to Zircaloy-4 with respect to fretting wear. [ABSTRACT FROM AUTHOR]

A wear life prediction of a grease-lubricated bearing in earth moving machinery has to be made based on actual wear data for its accuracy, but much effort should be devoted to obtain the wear data from the actual bearing. Currently, manufacturers provide a very conservative maintenance guide to schedule the replacement of the bearings to prevent the mechanical failure due to wear, causing economic losses, and the market requires finding optimal maintenance cycles to reduce maintenance costs. In this study, an economical wear prediction methodology for the grease-lubricated bearing based on typical pin-on-disk (POD) tests is proposed. POD tests were performed under boundary and mixed lubrication regimes considering the actual operating conditions of the bearings. It was found that there is a linear relation between the lubrication film parameter and the wear coefficient in log-log scale. The amount of wear of actual bearings was estimated by the wear coefficient from the linear regression analysis based on the POD test. The wear tests were further performed with the actual bearing under two loading cases and then the lubrication film parameter and wear coefficient were calculated, respectively. The estimated amount of wear shows good agreement with the measurement of wear depth. This leads us to conclude that it is possible to economically predict the wear amount in an actual bearing from POD wear test results by analysis of the correlation between the wear coefficient and the lubrication film parameter. [ABSTRACT FROM AUTHOR]

This study investigated the wear performance of phenolic composites under various conditions. Samples of brake pad material (UCV018) were subjected to friction and wear tests against grey cast iron (HT250) under dry sliding conditions. The friction coefficient and wear rate as well as material properties, such as density, elastic modulus, and Poisson ratio, were measured at six temperatures. The wear behavior of the friction material was analytically and numerically simulated using experimental data. Numerical calculations were performed on the basis of Archard's linear wear model. Through further experimental verifications, the friction and wear behavior were analyzed under conditions of static loading, quasistatic rotation, and wear. The friction and wear test results verified the accuracy of the simulation model and revealed the distribution of wear depth and contact pressure. Furthermore, the effects of contact pressure variation on wear performance were studied numerically. The results of the experimental and numerical investigations were compared. [ABSTRACT FROM AUTHOR]

The aviation, automobile, and consumer products industry requires long-life, durable, lightweight highperformance polymer matrix composites. Polymer fiber reinforced materials possess low weight and high specific quality along with high specific stiffness. The addition of carbon nanoparticles in the composites improves their mechanical properties, including wear enhancement, which leads to the utilization of these composites in different fields. The present work investigates the wear performance of glass fiber and carbon nanotube (CNT) reinforced hybrid polymer composites. Dry sliding tests for wear were conducted using a pin-on-disc wear tester by varying the load and speed. The worn surfaces were examined by utilizing scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, and atomic force microscopy. The result shows that the increase in volume percentage of CNTs in glass fiber reinforced polymer composites decreases the wear rate. The result also clearly states that the coefficient of friction increases with an increase in the CNT percentage. [ABSTRACT FROM AUTHOR]

Since the first use of oil drill bits to penetrate petroleum and gas wells, the wear of the teeth and bearing (for roller-cone bits) and cutters for (Polycrystalline Diamond Compact (PDC) bits) has been a major dilemma that causes money and time loss, consequently affecting the whole drilling operation. The present study reviews wear mechanisms in both bit types. The review has carried out the previous and the state of the art approaches for improving the drill bits against wear. Advantages and disadvantages of the conventional technologies for improving the manufacturing of the drill bits are explained. Conventional and emerging approaches of wear testing of drill bits are shown to expand the scope for developing the manufacturing of more reliable drill bits against the wear. We report a literature survey of the old and current methods of wear quantification in terms of drilling parameters and mechanical properties of the minerals forming the drill bits, and means of increasing the efficiency of oil and gas drill bits. Empirical wear models, as well as wear prediction techniques while drilling are discussed along with the simulation wear models using Finite Element Analysis (FEA) and the Discrete Element Method (DEM). [ABSTRACT FROM AUTHOR]

In order to improve the hardness and wear resistance of Ti materials, TiB/Ti64 composite coatings were synthesized by two-step method. Microstructure analysis reveals that a dense composite layer reinforced by two-scale TiB and well bonded with substrate was synthesized, and the coarse primary TiB prism (width: 7–17.5 μm) and fine eutectic TiB whisker (width: 0.3–1.2 μm) were free of reinforcement/matrix interfacial chemical reaction. Consequently, the hardness of the composite coating was significantly improved by two-scale TiB reinforcements, self-joining structures and strong reinforcement/matrix interface. Nanoindentation tests indicate that coarse primary TiB zone exhibited superior hardness, modulus and wear resistance, which was more beneficial to enhancing the coating performance. Besides, the hardness increased with the increasing TiB content and decreased with the increasing heat input, and the maximum hardness (HRC 60) was obtained by employing 29.4 wt.%TiB 2 +Ti64 powders and cladding at 162.7 J mm −1 , which is 80.2% higher than that of substrate (HRC 33.3). Meanwhile, the friction coefficient of the composite coating (0.14) was also significantly decreased compared with that of substrate (0.40). [ABSTRACT FROM AUTHOR]

The purpose of paper is to investigate the microstructure and properties of Cu-Cr alloys induced by high-current pulsed electron beam (HCPEB) irradiation. Microstructure of the alloying layer was studied by means of X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscopy (TEM). The microhardness and friction property were also tested. The microstructure reveals that craters were formed which were fused and eliminated to form flat surface with increase of the pulse number. Additionally, the inter-diffusion of Cu and Cr elements caused component homogenization of the surface melted layer. Besides, the fine grains/particles and Cu (Cr) solid solution were formed. Those factors accounted for a significant increase in microhardness. The lowest COF and wear rate were attributed to the ultrafine Cr particles in the hard Cu matrix. [ABSTRACT FROM AUTHOR]