Friction Temperature Research Articles

Abnormal fretting wear behavior of Fe-based amorphous coating

To promote the application of Fe-based amorphous coating (AMC)-protected magnesium alloys in fretting wear conditions, a Fe-based AMC with a thickness of about 164 μm was deposited on AZ31B magnesium alloy substrate by detonation spraying. The microstructure and fretting wear behaviors against GCr15 counterpart ball in different frequencies of the Fe-based AMC were studied in detail. The results show that the Fe-based AMC has a substantially complete amorphous structure, the porosity and surface hardness are ≤1.2 vol %, and 764.7 ± 37.5 Hv0.1, respectively. Therefore, the Fe-based AMC presents excellent fretting wear resistance, and its wear rate is almost 1/10 of that of AZ31B magnesium alloy, and 1/5 of that of high-velocity oxygen-fuel sprayed 316L stainless steel coating on AZ31B magnesium alloy substrate. The fretting wear behavior of Fe-based AMC was found to be sensitive to the fretting frequency: as the frequency increases from 5 to 100 Hz, the average steady-state friction coefficient increases from 0.77 to 1.07, but the wear rate exhibits an anomalous phenomenon, decreasing from 5.26 × 10−5 mm3N−1m−1 to 3.47 × 10−5 mm3N−1m−1. The improvement in wear rate is mainly attributed to the formation of an oxygen-rich river-like friction layer on the worn surface as the transient contact temperature increases with frequency, effectively suppressing delamination wear. Additionally, the occurrence of high transient frictional temperatures at high frequencies leads to evident crystallization within the coating, accompanied by the formation of nanocrystals, oxide films, and a large area river-like friction layer consisting of debris-compacted layers, which strengthens the Fe-based AMC. Consequently, the wear mechanism changes from delamination wear and abrasive wear at low frequencies to oxidative wear and adhesive wear at high frequencies, resulting in superior fretting wear resistance of the Fe-based AMC at high frequencies.

Examining the potential of sigma-thermic heat transfer fluid and its nanofluid in a natural circulation loop through CFD studies

This study investigates the impact of hot heat exchanger (HHX) inlet temperature on Sigma-thermic heat transfer fluid (STHF or STF) performance in a natural circulation loop. Various fluids, including STHF and STHF-based nanofluids, with volumetric concentrations ranging from 0.5% to 3%, are employed in the loop. The primary objective is to analyze the thermal performance of the loop under different conditions, focusing on temperature distribution, Nusselt number, friction factor, effectiveness, and mass flow rate. 3D numerical simulations are conducted, and the numerical model is validated against existing literature. The developed model incorporates considerations for viscous dissipation and axial conduction to predict the heat transfer potential of the loop. As the HHX inlet temperature increases, the mass flow rate rises. Notably, STHF/CuO nanofluids exhibit a more substantial enhancement than other nanofluids. At a 1 vol% concentration, the mass flow rate increases by 9.5%, 4%, and 2.7% for STHF/CuO, STHF/Al2O3, and hybrid nanofluids, respectively, compared to pure STHF. The study reveals significant improvements in mass flow rates and heat transfer efficiency with increasing HHX inlet temperatures, especially with STHF/CuO nanofluids. The total entropy generation reduction is notable, with percentages ranging from 2% to 18.5% for various nanofluids compared to pure STHF.

Greases for electric vehicle motors: Bearing friction torque under driving cycle conditions and the thickener effect on oil release

Performance of Lithium Complex (LiX), Polyurea (PU), and Polypropylene (PP) greases in SKF6208 bearings subjected to driving cycle conditions for 28 days (equivalent to 23,000 km of electric vehicle operation) was studied by continuously measuring bearing friction torque and temperature. The energy dissipation was correlated to the differences in oil bleeding and rheology for the three greases. Evolution of the friction torque, friction torque hysteresis, and changes in grease rheology were dominated by the oil release property. The latter was determined by the thickener system and its particular response to the conditions imposed by the driving cycle. A quantitative estimate of the carbon footprint from using these greases to lubricate bearings under driving cycle conditions is also presented.

The evaluation of error estimation for the Casson hybrid nanofluid flow in the uniform gap between two tubes for drug delivery applications

ABSTRACT Hybrid nanofluids are capable of being used as a carrier for delivering drugs to targeted areas in the body. For this purpose, the Casson hybrid nanofluids (HNFs) flow is suggested between the gap of two tubes. The study involves analyzing blood-based hybrid nanofluids (HNFs) that consist of silver (Ag) and titanium dioxide (TiO2) nanoparticles for applications of drug delivery. Titanium oxide nanoparticles, or TiO2 NPs, have strong photoactivity, low toxicity, and excellent biocompatibility, making them promising candidates for cancer treatment. The attractiveness of silver nanoparticles (AgNPs) for cancer therapy is due to their unique properties. Graphic representations are provided based on the simulations of non-dimensional velocity, temperature, and skin friction under physical parameter variations, for the applications of drug delivery are investigated and discussed. The control volume finite element method (CVFEM), is used to solve the problem. The new strategy of artificial neural networks (ANN) is also used to solve the transform equations. Nanoparticles increase drug stability and extend shelf life by protecting them from degradation or inactivation.

Flow analysis of MHD ternary hybrid nanofluid over a permeable wedge with variable surface temperature and slip effect

A comparative flow analysis of a water based- ternary hybrid nanofluid has been studied in this article over a moving permeable wedge in the presence of variable wedge surface temperature. The model has been developed keeping in mind magnetic, velocity slip, buoyancy, and suction effects. The primary nanoparticle was Nimonic 80A, Fe 3 O 4 being the secondary nanoparticle and Graphene Oxide ( GO ) ternary nanoparticle. The velocity, temperature, heat transfer rate, and shear drag profiles for various parametric values of the magnetic parameter ( M ), velocity ratio parameter ( R ) , velocity slip parameter ( h ) , buoyancy parameter ( γ ) and suction parameter ( S ) was investigated. MATLAB bvp4c code was utilized for obtaining the numerical results by solving the nondimensional differential equations obtained using similarity transformations. All the results and graphs were formulated after a positive outcome of our results with that available in existing literature. An increase in the velocity slip parameter ( h ) and velocity ratio parameter ( R ) resulted in an increase in velocity profiles and local Nusselt number graphs while a reverse trend was observed for temperature and skin friction profiles. Also, the velocity graphs faced an increase by 0.09% with an increment in M = 0.4 to M = 0.8 . The present study finds its extensive applications in medical industries, water heaters, and forging of hot exhaust valve heads.

Investigation of hot deformation behavior and microstructure evolution of TC18 alloy and establishment of constitutive equation under friction-temperature correction

The effects of deformation temperature and strain rate on the microstructure evolution of TC18 alloy are studied by hot compression experiment and EBSD test, based on the double correction of friction and temperature rise in hot compression, a more accurate constitutive equation and thermal processing diagram are established. Recrystallization grain is the main microstructure of TC18 alloy during deformation from 810 °C to 930 °C. Higher deformation temperature and lower strain rate are beneficial to the occurrence of dynamic recrystallization and grain size growth. The strain rate has no significant effect on volume fraction of large and small angle boundary. After double correction of temperature rise and friction, it is found the activation energy of TC18 titanium alloy in β region and α/β region are 485.895 kJ/mol and 355.337 kJ/mol, respectively. The ideal hot working conditions of TC18 titanium alloy are 812 °C ∼ 840 °C, 0.01 s−1 ∼ 0.018 s−1 and 878 °C ∼ 915 °C, 0.178 s−1 ∼ 1.0 s−1, respectively. The unevenness of microstructure, the large size difference among grains and the large orientation difference among grains lead to the instability of hot working process. The conclusions of this paper can provide more accurate guidance for the determination of hot working parameters and the prediction of microstructure evolution during hot working of TC18 alloy.

3D printing path method for multi-tow continuous carbon fiber

Carbon fiber composite materials have many excellent characteristics such as high temperature resistance, friction resistance, thermal conductivity and corrosion resistance, so carbon fiber composite materials have become the first choice for printing materials. In order to improve the printing efficiency of carbon fiber 3D printing technology, it has been expanded to four side-by-side nozzles based on traditional single nozzles, and four nozzles are bound to print side by side. The four-nozzle side-by-side printing path has the problem of coordinating the motion planning of each nozzle, controlling the squeezing difference of each nozzle, and adjusting the angle of the print head, so it is necessary to reasonably control the squeezing amount of each nozzle and the angle of the print head. After the slicing processing based on the existing model, the Gcode code of the model is obtained. The Gcode code of the model is processed through the multi-tow continuous carbon fiber 3D printing path planning algorithm. The movement trajectory of each nozzle of the printer is reasonably planned based on the outer wall coordinates and the extrusion amount of each nozzle is controlled. Finally, the snipping instruction is executed after a circle of trajectory to print the next layer of motion trajectory, which ultimately improves the 3D printing while ensuring the accuracy of multi-beam model 3D printing.

Corrosion, wear and machinability studies on scrap aluminium alloy wheel based metal matrix composite

Recycled materials, especially scrap aluminum alloy wheels with reinforcement castings, are gaining applications in various fields such as aerospace, naval, military, and automobile. In this research, Honda car alloy wheels are stir-cast with 5% alumina as reinforcement and subjected to corrosion, wear, and machinability studies. Corrosion studies were conducted to evaluate the corrosion current density (ICorr), corrosion potential (ECorr), and corrosion rate for the cast aluminum metal matrix composite. The wear studies with different loads, i.e., 50 N, 60 N, 70 N, and 80 N, were performed on the specimen and investigated the coefficient of friction, frictional force, and pin temperature. The sliding load has a significant effect on wear performance, and for the sliding load of 80 N, the wear recorded was 2574.83 µm. The electrochemical machinability studies with voltage, duty cycle, and concentration of citric acid electrolyte are performed on the machining rate and surface corrosion factor. Analysis of the electrochemical machining process with PROMETHEE-II shows that 7 V, 60% duty cycle, and 30 g/L electrolyte concentration are estimated to be the best combination for a higher machining rate and a lower surface corrosion factor. KEY WORDS: Alumina, Machining rate, Nyquist plot, Electrochemical machining, PROMETHEE-II Bull. Chem. Soc. Ethiop. 2024, 38(4), 1163-1175. DOI: https://dx.doi.org/10.4314/bcse.v38i4.27

High temperature friction and wear behavior of Mo–Si–B/ZrB2 composites

The Mo–Si–B alloys with good wear resistance are prominent for high-temperature applications. In this work, the effects of ZrB2 content and test temperature on the tribological properties of the Mo–Si–B/ZrB2 composites at 25–800 °C were investigated. It indicates that the composites show an enhanced wear resistance, which can be ascribed to the improved hardness and formation of Zr-rich borosilicate layer by introducing ZrB2 particles. The main wear mechanism is abrasive wear accompanies with adhesive wear at 25–400 °C, where ZrB2 addition can reduce the wear loss. And adhesive wear dominates at 600–800 °C, where the formed tribo-layer can provide a good self-lubricity and is beneficial for improving the wear resistance of the composites.

High-Temperature Tribological Behavior of Fast-Hot-Pressed NiCr/Cr3C2-LaF3 Self-Lubrication Composite

This article details a method for preparing cermet matrix composites via Fast hot pressing (FHP) sintering technology and emphasizes their potential use in extremely high-temperature settings. The material primarily consists of NiCr alloy, Cr3C2, and LaF3. An in-depth investigation was conducted on the tribological properties of the specimen by conducting sliding tests against a Si3N4 ball at varying temperatures, including room temperature (RT), 400 °C, 600 °C, and 800 °C. Advanced techniques such as scanning electron microscopy, micro-XRD, and micro-Raman spectroscopy were employed to examine the friction surfaces formed under different frictional temperatures. The findings reveal a uniform composition and high density within the composites. It is noteworthy that as the LaF3 content increases, the hardness of the ceramic phase diminishes. Conversely, the hardness of the alloy phase augments with the addition of LaF3, provided that its content remains below 15 wt%. The composite material containing 15 wt% LaF3 demonstrates superior hardness values, with the ceramic phase reaching HV1412 and the alloy phase achieving HV384. Furthermore, the coefficient of friction of the composite material was evaluated. The coefficient of friction of the composite is between 0.74 and 0.4 and the wear rate is 4.46 × 10−6–5.72 × 10−5 mm3N−1m−1 from room temperature to 800 °C. The lubrication behavior at low temperature is mainly attributed to the lubricating effect of LaF3, and at high temperature it is due to the tribochemical reaction to form LaCrO3 with good lubricating properties, which plays a synergistic lubricating role with Cr2O3.

Coupling Effect of Structural Lubrication and Thermal Excitation on Phononic Friction.

This work investigates the coupling effect of structural lubrication and thermal excitation on phononic friction between black phosphorus (BP) layers. As the rotation angle increases from commensurate to incommensurate states, the friction gradually decreases at any temperature. However, the role of temperature in friction depends on commensurability. For a rotation angle less than 10°, increasing temperature leads to a decrease in friction due to thermal excitation. Conversely, when the rotation angle exceeds 10°, elevated temperature results in an increase in friction due to the effect of thermal collision. At a critical rotation angle of 10°, higher temperatures lead to reduced friction through thermal lubrication at low speeds, and at large speeds, the thermal excitation duration becomes so short that the role of thermal lubrication is weakened, and instead thermal collision dominates. Further research reveals that BP's ability to withstand different maximum speeds is also determined by commensurability. Finally, a method to measure the sliding period length of a rotated tip through an unrotated substrate potential energy topography is proposed and simply verified by using the phonon spectrum.

Numerical and experimental investigation of textured journal bearings for friction reduction

This work investigates the mechanisms for friction reduction in textured journal bearings. The measured friction of laser-etched connecting-rod big-end shells was compared with a non-textured reference under engine-like conditions. Experiments covered several working conditions, and the friction and lubricant film temperatures were measured for three texture configurations. The origin of the verified friction reduction was explored using a numerical model that simulates the hydrodynamic lubrication and global thermal effects. The simulation results accurately matched the friction measurements, revealing that the microscopic mechanisms of reduction in lubricant shear stress and effective viscosity due to texture-induced cavitation act simultaneously to reduce the friction coefficient for the textured shells. The findings have practical applications for the optimal design of textured hydrodynamic bearings.

Effect of operating conditions and surface roughness on grease lubrication efficiency

The aim of this paper is to investigate the effect of operating parameters (load and rotational speed) and arithmetic mean deviation (Ra) roughness value on temperature rise and tribological behavior of greased point contact under heavy load. The 3-factor, 4-level orthogonal friction experiments are designed and carried out. The moving point heat source integration method is applied to calculate the transient temperature rise of interfaces. The results show that the case with load 1900 N, rotational speed 260 rpm and Ra 0.4 μm has the highest friction coefficient and temperature rise. The grease fails and layered spalling and oxidative wear occur on the wear scar. Four second-order regression models are established to predict friction coefficient and the maximum temperature rise under different load, rotational speed and surface roughness. And the determination coefficients R2 of them are higher than 97 %. The models are helpful to determine if the working conditions fall within effective lubrication range and avoid severe damage.

Stagnation point flow in a Maxwell fluid with a slip condition and the role of viscous dissipation and radiation

This research aims to examine the impact of viscous dissipation, slip conditions, and radiation on the stagnation point flow when a stretching/shrinking sheet is immersed in a Maxwell fluid. The significance of viscous dissipation has great importance in an extensive range of engineering applications, including heat exchangers, lubrication systems, polymer processing, and biofluid mechanics. In heat and mass transfer fluid flow problems, viscous dissipation can have significant effects, particularly in situations involving high fluid velocities or high viscosity fluids. In this computational study, the governing equations, namely the momentum, and energy equations, are formulated and non-dimensionalized using appropriate similarity parameters and the Runge-Kutta-Fehlberg method is then employed to resolve the problem. The obtained results provide detailed insights into the velocity, temperature, skin friction and wall temperature distributions in the flow domain. Additionally, the role of viscous dissipation in altering the heat transfer characteristics of the Maxwell fluid is examined. The results indicate that the existence of viscous dissipation significantly impacts the flow behaviour of the Maxwell fluid. It alters the boundary layer thickness, temperature distribution, and the overall heat transfer rate. Additionally, it is observed that the values of the Prandtl number strongly affect the influence of viscous dissipation on the velocity and temperature distribution. The outcomes of this study correlate with those that have been previously reported.

Launching dynamics of terminal guidance projectile considering barrel erosion and mechanical wear

This paper simulates the launching dynamics of the Terminal-guidance projectile considering the barrel thermo-chemical erosion wear and mechanical wear. A thermochemical erosive material degradation model that considers the rise in friction temperature is first introduced. Moreover, the wear state of barrel rifling at different periods is calculated using the erosion wear model. A three-dimensional model of the worn barrel is established, and the coupled barrel– terminal-guidance projectile launch dynamics are simulated for different wear periods. Finally, the projectile's bore overload and attitude are analyzed to explore the effect of barrel wear on launch.

Dynamic Characteristics Analysis of High-Speed Fixed-Axis Gear Pair with Spalling Fault for a Wind Turbine Gearbox Considering Friction and Flash Temperature

Dynamic Characteristics Analysis of High-Speed Fixed-Axis Gear Pair with Spalling Fault for a Wind Turbine Gearbox Considering Friction and Flash Temperature

Effect of Variable Viscosity on Entropy Generation Analysis Due to Graphene Oxide Nanofluid Convective Flow in Concentric Cylinders

Aggregated studies of graphene nanoparticles is important for the effective utilization of their striking thermophysical properties and extensive industrial applications. This investigation is one such computational study to explore the flow of graphene oxide nanofluids with temperature dependant viscosity between two concentric cylinders. Buongiorno model is used to develop the flow of graphene nanofluids including the impacts of Soret and Dufour effects and the effects of nanoparticle characteristics such as thermophoresis and Brownian motion. The modelled equations are transformed and are numerically solved using linearization method together with Chebyshev’s spectral collocation method under convective conditions. The impacts of embedded parameters on temperature, concentration and skin friction profiles of the chosen nanofluid and their consequent impacts on the predominant cause for the generated entropy are studied. From the tabulated values of Nusselt number and Sherwood number, it is observed that convective heat transfer can be enhanced by thermal Biot number whereas Soret number enhances diffusive mass transfer and variable viscosity parameter preferably reduces the skin friction. A comparison table is presented and it shows that the values obtained from the present method are in good agreement with existing literature. Also, the obtained results are depicted and interpreted in detail. Furthermore, entropy generation is analysed and its irreversibilty is calculated.

Sepiolite: A new component suitable for 380 ​km/h high-speed rail brake pads

To enhance the high-temperature adaptability of copper-based composite materials and C–C/SiC discs, this article innovatively introduces a method of replacing graphite with sepiolite, resulting in the successful fabrication of samples with exceptional mechanical and friction properties. The results reveal that moderate incorporation (less 6%) of sepiolite provides a particle reinforcement effect, resulting in an improvement of mechanical properties. Interestingly, the addition of sepiolite causes a change in the traditional saddle-shaped friction curve due to high temperature lubrication. Meanwhile, the primary advantage of sepiolite lies in its superior abrasion resistance, evident in the increased friction coefficient and altered wear mechanisms with higher sepiolite content. The wear resistance is optimal at 200 ​Km/h (400 ​°C). Particularly, the unique composition of the friction layer (outermost layer: a composite film consisting of B2O3, sepiolite, graphite, and metal oxide films; intermediate layer: metal oxide films) plays a pivotal role in improving friction stability. Finally, there are significant optimizations in the GA algorithm, especially GA-GB model has the best prediction effect on the maximum friction temperature.

Viscous dissipation and Joule heating effects on the unsteady micropolar fluid flow past a horizontal surface of revolution

This study aims to investigate the Joule effect, thermal radiation, and Coriolis effects in unsteady magnetohydrodynamics (MHD) micropolar flow over a 3-D unstable sheet. A magnetic field is typically applied to the surface; additionally, it is assumed that the fluid is conducting electricity. Other micro-rotations are also considered. The physical issue is resolved with the help of the fundamental equations, and the issue's complexity is reduced with the use of similarity variables. In the present approach, the homotopy analysis method (HAM) is employed. The heat, skin's friction factor, temperature, micro movements, and velocity associated with the emerging parameters and transfer rates are considered. The boundary layer thickness is increased as the parameter of vorticity increases. When the magnitude of the magnetic field increases, the skin friction coefficient decreases. The state variables are approximated up to six decimal places numerically. The numerical values of −f″(0) and −θ′(0) are computed to higher decimal places and compared with the available literature to validate the results. The outcomes obtained are compared with the available literature; the results here are corroborated, and the performance of the HAM is demonstrated.

Effect of Aging Temperature on Microstructure, Mechanical, and Wear Properties of 18Ni-300 Maraging Steel Produced by Powder Bed Fusion

Additive manufacturing technologies for metallic materials based on powder bed fusion have enormous industrial potential. In this study, we manufactured 18Ni-300 maraging steel using the powder bed fusion (PBF) process and investigated the effects of annealing temperatures of 430 °C, 490 °C, and 550 °C for 3 h on its microstructure, tensile fracture mechanism, and wear properties compared with the as-built specimen. The results show that annealing heat treatment effectively improved the dry sliding friction, wear properties, and room temperature tensile properties compared to the as-built specimen. Compared to other aging-treated samples, specimens that underwent heat treatment in optimal settings had superior properties. With optimal heat treatment, while melt pool boundaries remained, the cellular and columnar structures became finer compared to the un-treated specimens, and the number of dimples decreased. Consequently, the hardness and tensile strength improved by approximately 56.17% and 40.63%, respectively. The 18Ni-300 maraging steel sample that underwent heat treatment at optimal settings exhibited a coefficient of friction approximately 33.33% lower than the as-built alloy.