Wear Testing Machine Research Articles

Microstructure and tribological properties of WC-12Ni/Cu composite coating prepared by laser cladding on 45 steel surface

Abstract To reduce the amount of copper used and improve the service life of the copper layer in the plunger pair of a plunger pump, Ni15 was chosen as the transition layer to assist in the laser cladding preparation of copper-steel composite materials. WC-12Ni powder was mixed into Cu powder at concentrations of 5, 10, 15, 20, 25 wt%, and different compositions of cladding layers were prepared using laser cladding technology. The microstructure of the cladding layers was analyzed by optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS). The microhardness of the composite coatings was tested using microhardness Vickers (MHV), and the tribological performance of the composite coatings was evaluated using the friction and wear testing machine (F&WM). The results showed that, in terms of microstructure, element diffusion occurred around the WC particles, and partial dissolution of WC particles at their sharp corners led to the formation of new compounds with other elements. Additionally, WC particles contributed to the refinement of the microstructure. In terms of performance, the microhardness of the composite coatings increased with the increase in WC-12Ni content, reaching a maximum of 412.5 HV0.1 when the content was 25 wt%. Regarding tribological properties, the composite coating with 20 wt% WC-12Ni exhibited excellent friction-reducing properties, with a stable coefficient of friction of 0.53. Both the 20 wt% and 25 wt% WC-12Ni composite coatings demonstrated good wear resistance, with wear rates of 4.4 × 10−4 mg/ N·m.

A Fractal Prediction Model for the Friction Coefficient of Wet Clutch Friction Plates

The motion state of the friction plate in a wet friction clutch is investigated by analyzing the causes of friction coefficient formation. This study establishes static and dynamic friction coefficient models for the friction plate based on a fractal model. The fractal dimension and scaling coefficient are studied to understand the fractal characteristics and variation patterns of the surface morphology of friction pairs during engagement. The MM6000 friction and wear testing machine is utilized for experiments, measuring surface morphology changes due to wear and changes in the engagement motion state of the friction plate. The theoretical content is compared and analyzed to verify the accuracy of the friction coefficient prediction model for the friction pair. Experiments are conducted on paper-based friction materials under different bonding pressures, and the relationship between bonding times and surface morphology changes is established. A comparative experiment between the joint motion state and dynamic simulation is performed, concluding that the micro convex contact model has certain accuracy in predicting the contact state of friction plates under various working conditions.

Influence of oil-water mixing conditions on the friction and wear performance of ship tail-bearing materials

This study addresses the lubrication challenges posed by oil-water mixtures that arise when vessels encounter adverse maritime conditions, including collisions, grounding, and reefing, which can lead to failures in lubrication systems during navigation. The research focuses on three representative ship tail-bearing composites: polymer material(K4), thordon material(SR), and tenmat material(FR). Various volume fractions of oil-water mixtures were prepared, and the rheological properties of these mixtures were examined using a rotational rheometer (MCR102). Additionally, the variation of friction coefficients of the composites about load and linear velocity under different oil-water mixtures was analyzed using a Ring-Block Friction and Wear Testing Machine. Following the experiments, the surface morphology of the composites was assessed, and the wear mechanisms were analyzed using a laser interferometric surface profiler (LI-type), a confocal laser microscope (CLSM), and a scanning electron microscope (SEM). The findings indicate that, under all lubrication conditions, the friction coefficients of the three materials exhibit a gradual decrease with increasing load and linear velocity.Furthermore, the wear of the materials initially increases and then decreases with rising oil content, with higher oil concentrations in the oil-water mixture correlating with reduced wear. The study reveals that the three materials experience significant abrasive and adhesive wear under adverse oil-water mixing conditions. This research offers valuable insights for developing friction substitutes for oil-water mixing bearings in specialized operational environments and guides the design of friction components in such bearings.

Instance segmentation of on-line wear debris using deep convolutional neural network with transfer learning

Purpose This study aims to apply deep convolutional neural network Mask-R-CNN algorithm based on transfer learning to realize the segmentation of online wear fragments. Design/methodology/approach Wear debris analysis is considered to be one of the most effective methods to maintain the condition of mechanical equipment. In this paper, the friction and wear testing machine was used to design pin-disk rotation, pin-disk reciprocation and four-ball test to produce cutting, sliding, laminar and fatigue debris. A semi-online sampling system was designed to collect ferrographic images containing various fragments. The images were rotated and flipped to augment the data and enhance the generalization ability of the model. The data set required for data analysis is established. Using COCO pre-trained Mask R-CNN data set as a benchmark, the region proposal network (RPN) is trained with labeled wear debris images to enhance the ability of RPN to recognize background and wear debris. Two transfer learning scenarios are tested in the network head of the Mask R-CNN. Findings The results show that the deep convolutional neural network is suitable for the automatic classification and detection of wear fragments. Through transfer learning and proper training configuration, the ferrographic image recognition based on Mask R-CNN achieves high accuracy. Originality/value The results show that the deep convolutional neural network is suitable for the automatic classification and detection of wear fragments. Through transfer learning and proper training configuration, the ferrographic image recognition based on Mask R-CNN achieves high accuracy. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0182/

Study on influence of friction conditions on the friction and wear performance of high-speed rail brake materials under high humidity environment

Purpose Using the multifunctional friction and wear testing machine independently developed by the research group, the friction and wear tests of different friction conditions (contact pressure and sliding speed) are conducted on the brake materials of high-speed trains with the ambient humidity of 95% and the initial temperature of the disk of 200°C. Design/methodology/approach Friction and wear. Findings The test results show that changing the friction conditions has a significant effect on the braking performance of high-speed trains. Originality/value YES. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0171/

Effect of Co Addition on the Microstructure and Mechanical Properties of Sn-11Sb-6Cu Babbitt Alloy.

A Babbitt alloy SnSb11Cu6 with 0-2.0 wt.% Co was synthesized using the induction melting process. This study examined the effect of cobalt (Co) on the microstructure, tensile properties, compressive properties, Brinell hardness, and wear properties of SnSb11Cu6 using optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), a universal tensile testing machine, a Brinell hardness tester, and a wear testing machine. The results indicate that the optimal quantity of Co can enhance the microstructure of the Babbitt alloy and promote microstructure uniformity, with presence of Co3Sn2 in the matrix. With the increase in Co content, the tensile and compressive strength of the Babbitt alloy first increased and then decreased, and the Brinell hardness gradually increased with the increase in Co content. The presence of trace Co has a minimal effect on the dry friction coefficient of the Babbitt alloy. When the Co content exceeds 1.5 wt.%, the friction properties of the Babbitt alloy deteriorate significantly. The optimized Babbitt alloy SnSb11Cu6-1.5Co was subsequently fabricated into wires, followed by conducting cold metal transfer (CMT) surfacing experiments. The Co element can promote the growth of interfacial compounds. The microstructure at the interface of the Babbitt alloy/steel is dense, and there is element diffusion between it. The metallurgical bonding is good, and there are serrated compounds relying on the diffusion layer to extend to the direction of the additive layer with serrated compounds extending and growing from the diffusion layer to the additive layer. Overall, Babbitt alloys such as SnSb11Cu6 exhibit improved comprehensive properties when containing 1.5 wt.% Co.

Enhancing dry sliding wear resistance of high-Mn austenitic steel by adding N

In this study, the wear resistance of two high-Mn austenitic steels, i.e., Fe−18.5Mn−7Cr−0.6C and Fe−18.5Mn−7Cr−0.6C−0.21N was tested in dry sliding friction on a disc friction and wear testing machine (MMU-5G). The wear behavior and microstructure evolution of the two tested steels were investigated. The results revealed that adding N enhanced the wear resistance of high-Mn austenitic steel due to the synergistic effects of hardness, wear hardening, and oxide layer. Interstitial N atoms increased the matrix hardness and decreased the stacking fault energy (SFE). The lower SFE facilitated wear hardening, and the active mechanical twins along with the higher dislocation density induced the formation of a thicker nanocrystalline layer with finer grains. The nanocrystalline layer with higher surface activity promoted the adsorption of a protective oxide layer. These factors decreased the surface roughness, coefficient of friction (COF), and wear rate of N-alloyed high-Mn austenitic steel. This study provided valuable insights into the application of N-alloyed high-Mn austenitic steels under dry sliding friction conditions.

Experimental investigation on short-time and long-time tribological performance of Fischer-Tropsch fuel compared with fossil diesel

ABSTRACT The Fischer-Tropsch (F-T) fuel, as an alternative fuel for internal combustion engines, can cause undesired wear issues on engine components mainly due to its almost zero sulfur content. In order to explore a conveniently accessible additive to improve the lubricity of the F-T fuel, this study conducted both short-time and long-time tribological performance experiments of the F-T fuel added with 200 ppm lubrication improver Infineum R655 and compared with commercial fossil diesel. A four-ball wear test machine was used to perform fuel anti-wear and load-carrying properties tests. Two four-cylinder fuel pumps with top clearance and flat top two types of plungers were, respectively, operated with the F-T fuel and diesel for 300 hours. The parameters characterizing the tribological performance of the fuel pump plunger couples before and after the durability test were measured, including roundness, straightness, depth of parallelism, line profile, sealing time, and fuel delivery amount. The anti-wear property test results show that the wear scar diameter of the metal ball is 0.59 mm for the F-T fuel, which is 7.8% decreased than that of diesel. The results of fuel load-carrying capacity experiment exhibit that the maximum nonseizure load of the F-T fuel is 246 N, which is better than that of diesel. Regarding the fuel pump bench 300-hour operating results, wear of the fuel pump plunger components was acceptable using the F-T fuel with the lubrication improver, without any modification of fuel pumps. Additionally, the improvement brought by this additive is applicable to the two common types of plunger components mentioned above. The results of this study reveal that the desired tribological performance of the F-T fuel can be achieved by adding the lubrication improver additive evaluated in this work.

Study on the Performance of Different Crystal Forms Nano MoS2 as Lubricant Additives in Reducing Wear and Friction

ABSTRACTIn order to investigate the anti‐friction and anti‐wear performance of different crystal forms nano MoS2 in paraffin oil. Freeze‐drying method combined with hydrothermal was used to prepare different crystal forms nano MoS2 and their microstructures were characterised by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). The anti‐friction and anti‐wear performance of MoS2 nanoparticles as lubricat additives under different working conditions was investigated by the ball‐and‐disk friction and wear testing machine and the mechanism of friction and wear reduction was investigated. The results showed that the thickness of the floral sheet MoS2 flakes was about 10 nm and the particle size of the spherical MoS2 was about 90 nm. When the addition concentration was 3 wt%, the friction coefficient of the floral sheet MoS2 in paraffin oil was lower at 0.094, which was 29.3% lower than that of the pure paraffin oil, the width of the abrasion marks was 24.2% lower than that of the pure paraffin oil and the wear rate was 71.6% lower than that of the pure paraffin oil; The friction coefficient of the spherical MoS2 with 2.5 wt% addition was 0.082, which was 38.3% lower than the friction coefficient of pure paraffin oil, 24.1% lower than that of paraffin oil in terms of wear scar width and 81.9% lower than that of paraffin oil in terms of wear rate.

Simulation and experimental verification of the orthogonal friction continuous wear of PTFE-Kevlar fabric liner

Woven fabric liners, which are customizable and maintenance-free, have extensive applications in self-lubricating spherical bearings. However, owing to the orthogonal anisotropy and non-homogeneous characteristics, their frictional and wear behaviors are complex. Currently, average performance testing is primarily based on long-term macroscopic wear experiments. However, unobservable parameters such as mesoscopic stress and pressure distribution in liners are bottlenecks in the experimental exploration of wear sources and mechanisms. Therefore, an innovative strategy for modeling orthogonal friction and continuous wear in non-homogeneous liners is presented. This approach has the potential to overcome experimental limitations and significantly expedite liner design and cost-effective validation. The initial step involves establishing a mesoscopic voxel-based planar model of the liner that maintains the topological relationship during wear processes. This is achieved by introducing a circular voxel mesh and spatial transformation methods. Based on orthogonal friction and wear assumptions, separate constitutive models for orthogonal friction and wear are developed. Using the CETR UMT-3 friction and wear testing machine, GCr15 is selected as the counterface material, the pin disc wear method is adopted to conduct sliding test on PTFE and Kevlar fibers, and the required wear constitutive parameters are fitted. Furthermore, incremental equations for the total wear are derived. An element wear fusion strategy is introduced. This approach leads to the development of a continuous wear algorithm for liners and subsequently to the establishment of a voxel-based finite element model with continuous wear capability in the form of a circular voxel grid. This method transcends experimental methods and allows for the determination of the mesoscopic contact pressure, stress distribution, and variations in the contact material composition patterns of liner. The accuracy of the average macroscopic wear prediction is validated experimentally. This method has the potential for practical applications in bearing design.

An investigation on tribology performance of Abutilon Indicum fibre reinforced polymer composites

This research work investigates the tribological characteristics of Abutilon Indicum Fiber (AIF) reinforced composites with epoxy as the binding agent. The Abutilon Indicum fiber reinforced composites were manufactured by compression molding technique. These composites were fabricated by varying the fiber volume fraction ranging from 5%, 10%, 15% and 20% respectively and considering the fiber length as a fixed factor due to its short length. This research paper illustrates the effects of different fiber volume fractions (5,10,15 and 20%) on the tribological properties such as Specific wear rate (SWR) and Coefficient of friction (µ) of Abutilon Indicum fiber reinforced composites. Sliding wear tests were carried out under dry environment conditions with pin-on-disc wear testing machine. The experiments were performed for each composite with different combinations of testing parameters, sliding loads (10, 20 and 30 N); sliding distances (1,2 and 3 km); sliding speeds (1,2 and 3 m/s). Shore D hardness of 78.22 is determined to be higher for 15% volume fraction of AIF composites. Results conclude that the addition of AIFs in these composites enhanced the tribological performance with good wear resistance in relation with the pure epoxy-based composites with 15% volume fraction of AIFs displaying best results with higher resistance to wear at various operating conditions. Composites produced with 20% volume fraction displays the effects of fiber agglomeration which in turn has an inverse effect on hardness; limits the wear resistance with higher friction and wear rate and such results agree well with the wear debris, pits and contact patches in micrographs. Optimal fiber volume fraction of 15% was suggested in fabrication of composites for usage of AIFs as friction material.

Preparation of the fluorinated graphene/epoxy resin anti-corrosion composite coating

In order to enhance the corrosion resistance of epoxy resin (EP) coating system, we put forward a facile approach to prepare hydrophobic fluorinated graphene (FG) filler for the EP coating by one-pot hydrothermal reaction in this work. Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), contact angle measuring instrument and scanning electron microscopy (SEM) were employed for the FG characterization. The SEM images of fracture morphology revealed that FG uniformly dispersed in epoxy resin matrix. Additionally, the excellent water resistance and the lower coefficient of friction of FG/EP coating was confirmed through the water absorption test and friction and wear test machine. The electrochemical impedance spectroscopy (EIS) demonstrated that the impedance value at the low frequency (|Z|0.01Hz) of 0.50 wt% FG/EP was 3.49 × 107 Ω·cm2 after being immersed in 3.5 wt% NaCl solution for 60 days, which was about 2 orders of magnitude higher than that of the pure EP coating (4.74 × 105 Ω·cm2). The 0.50 wt% FG/EP coating exhibited the superior anti-corrosion performance due to the FG with the two-dimensional sheet structure, uniform dispersion and hydrophobicity properties.

The evaluation of wear processes of the rolling-sliding contact by means of flake wear debris in dry and wet contact

One of the tasks of this paper is to explain the cause-and-effect relationship of the influence of operating parameters on the wear of the wheel-rail system where fatigue processes are initiated. In this way, learning about and defining the nature of the phenomenon, makes it possible to determine the reliability of component operation. The aim of this study was to determine the influence of operational parameters on tribological properties of the rolling-rail contact representing the wheel-rail association in real operating conditions. Determining the form of wear on the basis of laboratory tests carried out on an Amsler-type wear testing machine in the wheel-roller system makes it possible to determine the nature of changes occurring as a result of cyclic interaction of normal and tangential forces on the surface of the tested material, without the need for long-term and costly observation of the tested object in normal operation. Quantitative metallographic analysis of the morphology of wear debris was used to determine the intensity of surface wear. Determination of the influence of operational parameters on the stereological characteristics of wear debris makes it possible to predict the regenerative grinding of rails in service in the track and allows practical application by the sections of operation and diagnosis of the railway system.

Electrical and current-carrying tribological properties of CoCrFeNi-(Mo, Ti, W) high-entropy alloy coatings on copper alloys by infrared-blue composite laser cladding

Infrared-blue composite laser cladding technology is used to prepare highly conductive and wear-resistant CoCrFeNi-(Mo, Ti, W) HEA coatings on the surface of the copper alloy to overcome the problem of high reflectivity of copper alloy aiming to enhance the surface performance of copper alloy current-carrying friction part. The microstructure and electrical properties of the high-entropy alloy coating were investigated. The wear resistance of the coatings was tested under high-speed and high-current conditions using a self-made current-carrying friction and wear testing machine. The results show that fine-grain and second-phase strengthening significantly enhances the hardness of the high-entropy alloy coating. The high-entropy alloy coating maintains the excellent electrical conductivity of the copper alloy, with an overall conductivity remaining above 60 % IACS. During the current-carrying friction process, the CoCrFeNi-(Mo, Ti, W) HEA coatings exhibited good wear resistance, with wear rates of 0.84 g/h, 1.08 g/h, and 1.32 g/h, respectively. The wear mechanisms observed included varying degrees of adhesive wear, abrasive wear, fatigue wear, and arc erosion.

EFFECT OF TiC ADDITION ON MICROSTRUCTURE AND PROPERTIES OF LASER CLADDING AlCoCrFeNi2.1 COATINGS ON H13 STEEL

[Formula: see text][Formula: see text][Formula: see text][Formula: see text]xwt.%TiC ([Formula: see text], 6, 9) coatings were prepared on H13 steel by laser cladding (LC) technology. It was characterized by a friction and wear test machine, optical microscope (OM), X-ray diffractometer (XRD), hardness tester, etc. The effects of different TiC contents on the microstructure and properties of [Formula: see text] coatings were analyzed. The results show that the coating microstructure without TiC addition is dominated by coarse columnar crystals and dendrites. After the addition of TiC, the coated massive crystals and equiaxed crystals become finer. XRD analysis reveals that the phase structure of the coating has FCC, B2 solid solution phase and TiC-reinforced phase. TiC phase can significantly improve the hardness of the coating. The microstructure reveals that fine TiC particles are widely distributed among the dendrites of the FCC matrix. The hardness and friction wear experiments revealed that the average hardness of the coatings with TiC has increased significantly compared to that of the substrate. The hardness of the [Formula: see text] with 9%TiC coating increased by 184.6% compared to that of the substrate. The friction coefficient was the smallest at 0.748. The lowest self-corrosion current was [Formula: see text][Formula: see text][Formula: see text]. The [Formula: see text] with 9%TiC coating had the best corrosion resistance.

STUDY ON THE FRICTION AND WEAR PROPERTIES AND SURFACE INTEGRITY OF GCr15 BEARING STEEL UNDER DIFFERENT GRINDING METHODS

In the field of precision machining, there are two widely used grinding methods for the same type of abrasive, namely, fixed abrasive grinding, and free abrasive grinding. In this paper, we utilized a self-developed rolling-sliding ratio controllable friction and wear testing machine to investigate the friction and wear properties of GCr15 bearing steel ground by fixed/free abrasive grinding under rolling and sliding motion, with varying abrasive particle sizes. The surface morphology and roughness of the ground bearing steel were observed and measured using a laser confocal microscope and white light interferometer. Results showed that under rolling and sliding conditions, the coefficient of friction for fixed abrasive grinding was higher than for free abrasive grinding. Under sliding conditions, the grinding efficiency of the fixed abrasive wheel is higher. However, in the case of wheel blockage, the grinding efficiency would significantly decrease. Conversely, the grinding efficiency of free abrasive grinding was observed to be stable throughout the grinding process. Under the same conditions of abrasive particle size in the sliding state, free abrasive grinding showed better surface integrity of bearing steel compared to fixed abrasive grinding.

Microstructure and performance of AlCoCrFeNiCu(CeO2)X high-entropy alloy coatings by plasma cladding

AlCoCrFeNiCu(CeO2)X (x=0 wt%, 0.3 wt%, 0.6 wt%, 0.9 wt%, and 1.2 wt%) HEA coatings were applied via plasma cladding technology to a 35CrMo steel surface in this investigation. Electron back-scattering diffraction (EBSD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to analyze the phase composition and microstructure of the coatings. A microhardness meter, a nanoindenter, a wear test machine, and an electrochemical station were used to assess the coating performance. The findings demonstrate that the phase composition of the coatings is unaffected by the addition of CeO2, with all coatings consisting of FCC and BCC phases. CeO2 was added to the coatings to refine their grain size and increase their proportion of high angle grain boundaries (HAGBs), BCC phase content, and geometrically necessary dislocation (GND) density. These improvements led to significant increases in the microhardness and wear resistance of the coatings. The 0.3 wt% CeO2 coating has the best corrosion resistance, which is caused by a number of factors including the element distribution, grain size, content of each phase, and phase distribution of the coatings. The corrosion resistance of the coating increases and then decreases nonlinearly with increasing CeO2 content.

Effects of Tungsten Addition on the Microstructure and Properties of FeCoCrNiAl High-Entropy Alloy Coatings Fabricated via Laser Cladding.

This study examines the effects of different addition levels of tungsten (W) content on the microstructure, corrosion resistance, wear resistance, microhardness, and phase composition of coatings made from FeCoCrNiAl high-entropy alloy (HEA) using the laser cladding technique. Using a preset powder method, FeCoCrNiAlWx (where x represents the molar fraction of W, x = 0.0, 0.2, 0.4, 0.6, 0.8) HEA coatings were cladded onto the surface of 45 steel. The different cladding materials were tested for dry friction by using a reciprocating friction and wear testing machine. Subsequently, the detailed analysis of the microstructure, phase composition, corrosion resistance, wear traces, and hardness characteristics were carried out using a scanning electron microscope (SEM), X-ray diffractometer (XRD), electrochemical workstation, and microhardness tester. The results reveal that as the W content increases, the macro-morphology of the FeCoCrNiAlWx HEA cladding coating deteriorates; the microstructure of the FeCoCrNiAlWx HEA cladding coating, composed of μ phase and face-centered cubic solid solution, undergoes an evolution process from dendritic crystals to cellular crystals. Notably, with the increase in W content, the average microhardness of the cladding coating shows a significant upward trend, with FeCoCrNiAlW0.8 reaching an average hardness of 756.83 HV0.2, which is 2.97 times higher than the 45 steel substrate. At the same time, the friction coefficient of the cladding coating gradually decreases, indicating enhanced wear resistance. Specifically, the friction coefficients of FeCoCrNiAlW0.6 and FeCoCrNiAlW0.8 are similar, approximately 0.527. The friction and wear mechanisms are mainly adhesive and abrasive wear. In a 3.5 wt.% NaCl solution, the increase in W content results in a positive shift in the corrosion potential of the cladding coating. The FeCoCrNiAlW0.8 exhibits a corrosion potential approximately 403 mV higher than that of FeCoCrNiAl. The corrosion current density significantly decreases from 5.43 × 10-6 A/cm2 to 5.26 × 10-9 A/cm2, which suggests a significant enhancement in the corrosion resistance of the cladding coating.

Tribological behavior and characteristics of TIG surface cladded AlCoCrFeNi high-entropy alloy on 304L stainless steel

The present study examines the tribological properties of AlCoCrFeNi high-entropy alloy (HEA) surface cladded on 304L stainless steel via a Tungsten Inert Gas (TIG) heat source. Commercially pure powders of aluminum, cobalt, chromium, and nickel were ball-milled, mixed in specific ratios, and applied onto the substrate with polyvinyl alcohol as a binder. Cladding was performed with optimized parameters to create layers of HEA. Microstructural and EDS analysis revealed equiaxial dendrites rich in aluminum and nickel in dendritic (DI) areas, and rich in iron, chromium, and cobalt in interdendritic (ID) areas. Mixing entropy was calculated by consideration of EDS analysis of the cladding and based on the initial definition of a high-entropy alloy, the high-entropy nature of the cladding was confirmed. XRD analysis showed the presence of FCC, A2/B2, and hard σ phases. Surface alloyed material exhibited higher hardness compared to the base material, with an average of 540 HV versus 200 HV. A pin-on-disc wear test machine was used to assess tribological properties under different loads of 10, 20, and 40 N. The wear rates of the high-entropy cladded material were 36 and 50 % less than those of the 304L stainless steel under applied loads of 10 and 40 N, respectively, while their wear rates were almost similar at 20 N. Friction coefficients of HEA pins were notably lower than 304L at 10 and 20 N, with smoother profiles. Wear mechanisms of the HEA material varied with load: oxidative wear at 10 and 20 N due to the formation of an oxide layer, and abrasion and spallation at 40 N, resulting in a threefold increase in wear rate at this load. Overall, the study highlights the effectiveness of HEA cladding in improving tribological properties, especially under high applied load.

Influence of scanning speed on titanium alloy processed with TC4+Ni60/hBN composite powder by laser metal deposition coating technology

PurposeRegarding the broadening of the titanium alloy application field, the surface treatment coating of TC4 alloy has become an essential global research topic. This study aims to illustrate the titanium-based composite coating is created by laser cladding TC4+Ni60/hBN composite powder onto the surface of the TC4 alloy.Design/methodology/approachDifferent laser scanning speeds were initially selected to prepare TC4+Ni60/hBN titanium-based composite coating on the surface of TC4 alloy using RFL-C1000 Raycus fiber laser. Second, the cladding layers with different laser scanning speeds are composed of Ti2Ni, TiN0.3, TiC, TiB, α-Ti and other phases. Finally, precision balances, friction and wear testing machines were used to analyze and test the structure, phase, hardness, wear amount and friction coefficient of the composite coating and to study the effect of laser scanning speed on the microstructure and properties of the titanium-based composite coating.FindingsIt is evident that at the low laser scanning speed, the reinforcing phase agglomeration area is distributed in the substrate as a network. Increasing the laser scanning speed can reduce the cladding layer's friction coefficient and improve the cladding layer's hardness and wear resistance. But too high a laser scanning speed will cause defects such as pores and cracks in the cladding layer and also affect the cladding layer. The bonding performance of the layer and the substrate is optimal in this research at a laser scanning speed of 10 mm/s.Originality/valueThis research has practical value in improving the quality of surface treatment coating in modern aerospace and automotive companies.