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Atomistic simulations performed with a family of model potential with tunable hardness have proven to be a great tool for advancing the understanding of wear processes at the asperity level. They have been instrumental in finding a critical length scale, which governs the ductile to brittle transition in adhesive wear, and further helped in the understanding of the relation between tangential work and wear rate or how self-affine surfaces emerge in three-body wear. However, so far, the studies were mostly limited to adhesive wear processes where the two surfaces in contact are composed of the same material. Here, we propose to study the transition from adhesive to abrasive wear by introducing a contrast of hardness between the contacting surfaces. Two wear processes emerge: one by gradual accretion of the third body by detachment of chips from both surfaces and the other being a more erratic mixed process involving large deformation of the third body and removal of large pieces from the soft surface. The critical length scale was found to be a good predictor of the ductile to brittle transition between both processes. Furthermore, the wear coefficients and wear ratios of soft and hard surfaces were found to be consistent with experimental observations. The wear particle is composed of many concentric layers, an onion-like structure, resulting from the gradual accretion of matter from both surfaces. The distribution of sizes of these layers was studied, and it appears that the cumulative distribution of hard surface's chip sizes follows a power law. [ABSTRACT FROM AUTHOR]

Ultrahigh molecular weight polyethylene (UHMWPE) is suitable for tribological applications in various environments because of its advantageous characteristics, including its high‐impact strength, excellent resistance against wear and corrosion, and self‐lubricating properties. However, the tribological behavior of UHMWPE under seawater lubrication is still poorly understood. In this study, the wear mechanisms of UHMWPE in seawater environment were elucidated by examining its morphology and structural evolution during sliding friction. The tribological properties of UHMWPE were significantly affected by the sliding speed in seawater. At low sliding speeds, no long‐strip structures were observed on the worn UHMWPE surface. However, as the sliding speed was increased, prominent convex long‐strip structures appeared and became more densely distributed with time. The molecular chains in the amorphous region of UHMWPE stretched along the sliding direction under stress. In the crystalline region, molecular orientation, and lamellar slip were accompanied by molecular conformational transformations. During the initial stage of sliding friction, UHMWPE mainly exhibited adhesive wear caused by plastic deformation. Subsequently, the wear mechanism of UHMWPE gradually changed from adhesive wear to a combination of adhesive and abrasive wear, and its wear intensified over time. [ABSTRACT FROM AUTHOR]

Ultralow-wear polyethylene (ULWPE) was proposed to replace conventional UHMWPE as an artificial joint material. Different molecular weights of ULWPE, ULWPE-200, ULWPE-300, and ULWPE-700 were examined against CrCoMo compared to conventional UHMWPE in multidirectional motion. The wear mechanism was elucidated from the perspective of macroscopic wear behavior and microscopic wear debris characterization. It was found that the morphologies of the ULWPE worn surface were similar to that of UHMWPE, with scratches, burnishing, and protuberances. ULWPE-700 possessed the lowest wear loss at all loading conditions, and the wear loss was 40.3% lower than that of UHMWPE at 3 MPa. Furthermore, wear debris was consistent in morphology and size range but showed differences in quantity, size distribution, and shape distribution. Combined with the wear surface morphology and wear debris analysis, it showed that plastic deformation was the main cause of wear debris formation and the wear mechanisms were adhesive wear and abrasive wear. Moreover, the FBA of ULWPE-700 was 64% lower than that of UHMWPE at 3 MPa, suggesting that ULWPE-700 wear debris had the lowest potential osteolysis. This study provides deeper insight into the bio-tribological behavior and the potential biological activity of ULWPE as an artificial joint material. [ABSTRACT FROM AUTHOR]

Ti6Al4V alloy–CoCrMo alloy pair is commonly applied for modular head–neck interfaces for artificial hip joint. Unfortunately, the fretting corrosion damage at this interface seriously restricts its lifespan. This work studied the fretting corrosion of Ti6Al4V–CoCrMo pair in calf serum solution. We established this material pair's running condition fretting map (RCFM) regarding load and displacement, and revealed the damage mechanism of this material pair in various fretting regimes, namely partial slip regime (PSR), mixed fretting regime (MFR), and gross slip regime (GSR). The damage mechanism of Ti6Al4V alloy was mainly abrasive wear induced by CoCrMo alloy and tribocorrosion. Adhesive wear (material transfer) also existed in MFR. The damage mechanism of CoCrMo alloy was mainly abrasive wear induced by metal oxides and tribocorrosion in GSR and MFR, while no apparent damage in PSR. Furthermore, a dense composite material layer with high hardness was formed in the middle contacting area in GSR, which reduced the corrosion and wear of Ti alloys and exacerbated damage to Co alloys. Finally, the ion concentration maps for Ti and Co ions were constructed, which displayed the transition in the amount of released Ti and Co ions under different displacements and loads. [ABSTRACT FROM AUTHOR]

High‐speed dry milling (HSDM) technology is one of the most attractive solutions for improving the cutting performance of difficult‐to‐machine materials. However, the study of HSDM performance for 30CrMnSiNi2A steel has not been reported. In this article, HSDM for 30CrMnSiNi2A steel is investigated using TiN‐coated and AlTiN‐coated tools, focusing on cutting force, vibration, surface roughness, residual stress, and tool wear. The effects of cutting parameters on cutting force and vibration are remarkably similar. At a spindle speed of 7500 r min−1, both cutting force and vibration are minimized. TiN‐coated and AlTiN‐coated tools exhibit distinct performance differences. But, HSDM of 30CrMnSiNi2A steel using TiN‐coated and AlTiN‐coated tools can achieve low surface roughness. The depth of cut significantly affects surface roughness, which is lowest at the depth of cut (0.8 mm). Most of the workpiece surface shows residual compressive stress. The main wear mechanisms for both coated tools are abrasive wear, adhesive wear, and oxidative wear. Furthermore, the AlTiN‐coated tool is more wear resistant on the flank face compared to the TiN‐coated tool. Chipping due to crater wear is the leading cause of tool failure for the AlTiN‐coated tool. Upon various comparisons, the AlTiN‐coated tool is more suitable for HSDM of 30CrMnSiNi2A steel. [ABSTRACT FROM AUTHOR]

Novel hybrid composite based on polyamide‐6,6 (PA‐6,6) was developed with graphene nanoplatelets (GnPs) and molybdenum disulfide (MoS2) as hybrid fillers reinforcement using melt‐mixing and injection molding techniques. The structural, thermal, mechanical and tribological characteristics of the hybrid composite were assessed by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), differential calorimetry analysis (DSC), tensile test as well as the friction and wear test, respectively. Compared to pure PA‐6,6, the PA‐6,6/GnPs/MoS2 hybrid composites exhibited enhanced thermal stability. Notably, the composites demonstrated significant improvements in tensile modulus and strength, particularly at a 5 wt.% of hybrid filler loading, showing an increase of ~59% and ~21%, respectively. However, the impact strength exhibited an opposite effect on hybrid filler reinforcements. Furthermore, the fractured surface morphology was analyzed using FESEM images. Moreover, the tribological performance was assessed with a linear reciprocating tribological (LRT) test using ball‐on‐plate tribo‐pair at different abrading frequencies (5 and 25 Hz) and normal loads (10, 30 and 50 N), revealing significant improvements in friction coefficient (CoF) and specific wear rate (WSR) characteristics for the hybrid composite up to 5 wt.% of hybrid fillers addition, attributed to the abrasive and adhesive wear mechanism. The worn surface morphology was further investigated using the FESEM micrographs to better comprehend the wear mechanisms. Therefore, the optimal performance of the developed hybrid composite was observed at 5 wt.% of hybrid filler loadings. Therefore, the developed hybrid composites' excellent thermal, mechanical, and tribological properties could be suggested for their potential utilization in lightweight automotive applications. [ABSTRACT FROM AUTHOR]

This paper examines the challenges of machining structural alloy steels for carburizing, with a particular focus on gear manufacturing. TiN0.85-Ti coatings were applied to cutting tool blades to improve machining quality and tool life. The research, supported by mathematical modeling, demonstrated that these coatings significantly reduce adhesive wear and improve blade life. The Kolmogorov–Arnold Network (KAN) was identified as the most effective model comprehensively describing tool life as a function of cutting speed, coating thickness, and feed rate. The results indicate that gear production efficiency can be significantly increased using TiN0.85-Ti coatings. [ABSTRACT FROM AUTHOR]

AbstractDrilling of aluminum matrix composite of silicon carbide materials is analyzed using cryogenically treated drills under cryogenic conditions. Vibration acceleration, thrust force, geometrical aspects of drilled workpiece like hole quality, surface roughness, tribology properties of drill wear and chip morphology are evaluated at various drilling parameters such as spindle speed and feed rate. Experimental results showed that impact of spindle speed is considerably higher than impact of feed rate on vibration acceleration, whereas thrust force is influenced by spindle speed as well as feed rate. The maximum vibration acceleration obtained at the highest feed rate is 74.48 m/s2 and 81.34 m/s2 at the spindle speed of 3,000 rpm and 4,500 rpm. The hole diameter variation is 0.139 mm than original drill diameter and observed entry side hole diameter is slightly larger than that of exit side. Moderate spindle speed i.e., 3,000 rpm and 4,500 rpm produced better geometrical aspects of drilled workpiece and it is recommended for smooth drilling operation under cryogenic drilling condition. Adhesive wear is found to be prominent specially at the higher spindle speed. Smaller and smooth chips are observed at the lower spindle speed while short and curly shape chips are found at higher spindle speeds. [ABSTRACT FROM AUTHOR]

Herein, the tribological behavior of 316L stainless steel (SS) fabricated using metal extrusion additive manufacturing (MEAM) is investigated both under dry and simulated body fluid (SBF)‐lubricated conditions. The results and mechanisms are compared with those of 316L SS fabricated via selective laser melting (SLM) and hot rolling (HR). Under dry‐friction conditions, the 316L SS fabricated via MEAM shows inferior tribological performance compared with those fabricated via SLM and HR, primarily because of its lower initial hardness and better plasticity, which increase both abrasive and adhesive wear. Under SBF‐lubricated conditions, the tribological performance of the 316L SS fabricated via MEAM is comparable to that fabricated via HR and superior to that fabricated via SLM. The wear rate of the MEAM‐fabricated 316L SS is 16.8% and 3.2% lower than SLM‐ and HR‐fabricated, respectively. The numerous pores on 316L SS serve as traps for wear particles, which contribute to the reduction of three‐body wear. In terms of wear under SBF‐lubricated conditions, MEAM technology appears to be a promising method for the fabrication of customized 316L orthopedic implants. [ABSTRACT FROM AUTHOR]

With low cost and excellent performance, 304 stainless steel has been widely used in construction, automobile manufacturing and other industrial fields. However, the low hardness and poor wear resistance will mark it prone to premature failure in service. To solve this problem, single-, double, and eight-layer coatings of Stellite 6 Co-based alloy were successfully deposited on 304 substrate subfaces by laser-based directed energy deposition technology in this study. The microstructure evolution of the deposited coatings and their interfaces with 304 substrate were investigated with their corresponding mechanical properties being discussed. The results show that the deposited coating is mainly composed of γ-Co dendrite and Cr7C3, Cr23C6 inter-dendrites. Additionally, the ratio of temperature gradient and solidification rate could decrease from the bottom to the top of the coating, which promoted the transformation of the grains of the coating layers from cellular at the bottom to large columnar with fine equiaxial ones at the top. Therefore, the microhardness could increase gradually from the substrate/coating interface to coating due to the refined microstructure, and the maximum value was 561.5 HV. The wear resistance of the well metallurgically bonded coating has also been improved, and the wear mechanism changes from adhesive wear of the substrate to abrasive wear. [ABSTRACT FROM AUTHOR]

The objective of this study is to improve the properties of polylactic acid (PLA), a biopolymer produced from renewable resources, without compromising its environmentally friendly "natural composite" properties. The aim was to expand the application range of PLA by making it suitable for the production of high performance composites. With this in mind, it was decided to use inorganic and environmentally friendly materials such as basalt fiber (BF) and boric acid (BA) as reinforcements. Adhesive wear and tensile tests were used to investigate the tribological and mechanical performance of the composites. Differential scanning calorimetry (DSC) and dimensional stability analysis (DSA) methods were used to investigate the thermal properties. Scanning electron microscopy analysis was also used to investigate the morphological properties of the samples. In addition, a matrix modification process using Joncryl®, an epoxy‐based chain extender chemical, was applied to enhance the interfacial interaction between the composite components and improve the composite properties by improving the dispersion of reinforcing materials. As a result of the characterization tests, it was observed that a significant improvement in the properties of the material type containing 10 wt% BF, 0.25 wt% BA and 2 wt% Joncryl® was achieved. A 19% increase in tensile strength of this type of material was observed compared with unreinforced PLA, while the sharp peak increase in the coefficient of friction (COF) curve was shifted from 20 m to 60 m. As a result, it has been presented that environmentally friendly and inorganic materials such as BF and BA can be used to produce composite materials that will serve sectors where the need and use of high performance materials is intense, especially in the automotive, aerospace and aviation sectors. Highlights: The properties of PLA matrix composites were improved by the simultaneous use of BF and BA and the addition of Joncryl®.The structural properties of PLA, an environmentally friendly polymer, have been improved without compromising this characteristic.PLA matrix natural composites with performance that can be used in the automotive, aerospace and aviation sectors have been developed. [ABSTRACT FROM AUTHOR]

Different contents of WC particle‐reinforced 18Ni300 composites are prepared by selective laser melting method, and the tribological properties are comparatively studied before and after solution aging heat treatment. The results show that a part of WC particles are dissolved, and no obvious pore defects appear. With the increase of WC content, the microstructure gradually transforms from cellular and fine columnar α‐Fe martensite to γ‐Fe austenite. After solution aging heat treatment, the phase is transformed into acicular martensite. The grain size significantly decreases, and the Vickers hardness increases. The grain size decreases and the hardness increases with increasing WC contents. For the as‐built composite, the friction coefficient first decreases and then increases, and the wear rate first increases and then decreases with the increase of WC content. With WC content increasing, the wear rate first decreases and then increases. After heat treatment, the tribological properties are improved. The groove of the specimens before heat treatment is deep with large delaminated craters, and the wear mechanism is dominated by adhesive and abrasive wear. The grooves become shallower, and the adhesive trace becomes lighter after heat treatment. The wear mechanism is mainly adhesive wear and abrasive wear, accompanying with oxidative wear. [ABSTRACT FROM AUTHOR]

In this research, wear resistance of chromium nitride (CrN) coated aluminum alloy with hydrogen charging was investigated. Delamination rates of the CrN coating layer after 6 and 12 h of hydrogen charging were measured to be 42.37% and 86.96%, respectively. In particular, damage by hydrogen attack was observed in the exposed area of aluminum alloy. Increasing in applied load and hydrogen charging time decreased the friction coefficient, and when the two factors interacted, a significantly higher increasing rate of wear damage was observed. The increasing rate in wear depth due to hydrogen charging was greater at the applied of 1 N than at 5 N. This is because hydrogen permeation affects the wear resistance of the CrN coating layer and aluminum alloy in the depth direction. In addition, re-transfer and re-adhesion of the CrN coating, whose adhesion strength had decreased due to hydrogen charging, actively occurred. • The high durability of hydrogen valve is a very important factor for the commercialization of fuel cells. • The surface damage and delamination of the CrN coating layer by hydrogen charging were obviously observed. • The delamination of the CrN coating layer occurred in a bulk, and the wear resistance decreased accordingly. • In particular, hydrogen charging affected the adhesive wear of CrN-coated specimens. • Nevertheless the CrN coating technology is significantly excellent performance for resistance of hydrogen embrittlement. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to examine the cutting performance of a coated carbide tool during the boring of 1Cr17Ni2 martensitic stainless steel, with a focus on how the tool's structural parameters, particularly the nose radius, affect the wear patterns, wear volume and lifetime of the cutting tool, and related mechanisms. Design/methodology/approach: A full factorial boring experiment with three factors at two levels was conducted to analyze systematically the impact of cutting parameters on the tool wear behavior. The evolution of tool wear over the machining time was recorded, and the influences of the cutting parameters and nose radius on wear behavior of the tool were examined. Findings: The results show that higher cutting parameters lead to significant wear or plastic deformation at the tool nose. When the cutting depth is less than the nose radius, the tool wear tends to be minimized. Larger nose radius tools have weaker chip-breaking but greater strength and wear resistance. Higher cutting parameters reduce wear for the tools with larger nose radius, maintaining their integrity. Wear mechanisms are primarily abrasive, adhesive and diffusion wear. Furthermore, the full-factorial analysis of variance revealed that for the tool with rε = 0.4 mm and 0.8 mm, the factors contributing the most to tool wear were cutting speed (38.76%) and cutting depth (86.43%), respectively. Originality/value: This study is of great significance for selection of cutting tools and cutting parameters for boring 1Cr17Ni2 martensitic stainless-steel parts. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2024-0266/ [ABSTRACT FROM AUTHOR]

In this paper, the friction properties of the port pair with non‐smooth surface in the pump were studied. The lubrication film was modelled and simulated to analyse dynamic pressure, velocity vector and friction coefficient. Tests were made for studying the effects of pit shape and revolution speed on friction properties of glass fibre epoxy resin (GFER) samples under seawater lubrication, with the wear of the surface and friction coefficient discussed. The results show that GFER is mainly manifested as adhesive and abrasive wear during the tests. The simulations and tests suggest that the hydrodynamic lubrication effect is improved by increasing revolution speed and using non‐smooth surfaces, with the friction coefficient being decreased. Moreover, a roughness test was conducted, and it was found that the Ra value of the 316L sample decreased, whereas the Ra value of the GFER sample increased. [ABSTRACT FROM AUTHOR]

Recent advances in materials science have shed light on the potential of refractory high-entropy alloys (RHEAs) to improve wear performance across varying temperatures. These alloys offer an optimal balance between strength and ductility, making them ideal for protective coatings. Despite the lightweight properties of Ti-6Al-4 V alloys, they still pose challenges when it comes to wear resistance. This study presents a lightweight coating using RHEAs made of AlCrNbMoV through laser cladding. Notably, the AlCrNbMoV coating exhibits a single-phase BCC structure and completes with diffuse regions enriched in titanium dendrites. In addition, the microhardness of the coating is measured at 792.4 (±6.5) HV0.5, showing a remarkable improvement compared to TC4. The wear rate at 600 °C for the AlCrNbMoV coating is measured at 0.43 (± 0.026) × 10 − 4 m m 3 / N / m , demonstrating a significant reduction of 91.43% when compared to the wear rate of TC4, which stands at 5.02 (± 0.081) × 10 − 4 m m 3 / N / m. The wear mechanism undergoes a transition from abrasive wear at room temperature to adhesive wear at 300 °C and then to fatigue wear at 600 °C. The study introduces new possibilities for the application of RHEAs in protective coatings, particularly in high-temperature environments such as aerospace. [ABSTRACT FROM AUTHOR]

The high weight-to-strength ratio of AA6061 aluminum alloys presents increased potential applications in industries such as automotive and aircraft. However, its limited formability at room temperature (RT) restricts its usage. Therefore, in the conducted study, the formability of AA6061-T6 sheets with a thickness of 2 mm was investigated at different temperatures in the range of RT up to 300°C. Both experimental and numerical methods were employed to investigate the forming limit diagram (FLD) of an AA6061-T6 sheet. The tests were conducted using a non-isothermal Nakajima standard die under dry contact conditions. Two damage criteria, the Johnson–Cook and the ductile fracture criterion (DFC), were used in a thermomechanically coupled finite element analysis in Abaqus/Explicit to predict fracture in the AA6061 sheet. To examine the impact of temperature on the friction coefficient in the punch and sheet contact, an atomic force microscope was used to measure the roughness of the sheet, after the FLD tests, were conducted at different temperatures. Results indicate an increase in FLD levels from RT up to 100°C, followed by a decrease, for temperatures surpassing 100°C. Experimental findings underscored the significance of the adhesive wear at elevated temperatures, acting as a decisive factor that hampers the material flow and the sheet deformation, in the contact between the sheet and punch. [ABSTRACT FROM AUTHOR]

The 7A04 Al alloy is a commonly used lightweight metal material; however, its low wear resistance limits its application. In this study, the wear resistance of this alloy was improved by preparing micro-arc oxidation (MAO) coatings, MAO/MoS2 composite coatings, and hard-anodized (HA) coatings on its surface. The friction and wear behaviors of these three coatings with diamond-like coated (DLC) rings under oil lubrication conditions were investigated using a ring–block friction tester. The wear rates of the coatings on the block surfaces were determined using laser confocal microscopy, and the wear trajectories of the coatings were examined using scanning electron microscopy. The results indicated that, among the three coatings, the MAO/MoS2 coating had the lowest coefficient of friction of 0.059, whereas the HA coating had the lowest wear rate of 1.47 × 10−6 mm/Nm. The MAO/MoS2 coatings exhibited excellent antifriction properties compared to the other coatings, whereas the HA coatings exhibited excellent anti-wear properties. The porous structure of the MAO coatings stored lubricant and replenished the lubrication film under oil lubrication. Meanwhile, the introduced MoS2 enhanced the densification of the coating and functioned as a solid lubricant. The HA coating exhibited good wear resistance owing to the dense structure of the amorphous-phase aluminum oxide. The mechanisms of abrasive and adhesive wear of the coatings under oil lubrication conditions and the optimization of the tribological properties by the solid–liquid synergistic lubrication effect were investigated. This study provides an effective method for the surface modification of Al alloys with potential applications in the aerospace and automotive industries. [ABSTRACT FROM AUTHOR]

In this study, the effects of applied pressure (0, 90, 120, and 150 MPa) during solidification on the microstructure, mechanical properties, and impact–abrasive wear resistance of Cr-Mn-Mo steel prepared by squeeze casting were systematically investigated. The results demonstrated that the materials produced under pressure showed smaller grains compared to those of the samples fabricated without pressure. Compared to the unpressurized sample, the grain diameter of the sample prepared at 120 MPa decreased by 37.7%, the length of the primary arm shortened by 40.7%, and the spacing of the secondary arm contracted by 14.1%. Furthermore, the impact toughness results indicated that the samples prepared without pressure exhibited brittle fracture characteristics, whereas quasi-destructive fractures predominated in the samples prepared at 120 MPa. Simultaneously, three-point bending strength exhibited a gradual increase with increasing pressure, reaching a maximum value of 855.5 MPa when prepared under 150 MPa. Additionally, the impact–abrasive wear resistance of Cr-Mn-Mo alloyed steel produced by squeeze casting was significantly enhanced compared to the samples produced without pressure. The samples without external pressure exhibited a combination of abrasive and adhesive wear, whereas the wear characteristics of the samples prepared under pressure includes grooves, cutting marks, flaking pits, and accumulating ridges. [ABSTRACT FROM AUTHOR]

PTFE coatings were deposited on YT15 carbide substrates using spray technology. A series of examinations were conducted, including the use of surface and cross-section micrographs to analyze the structural integrity of the coatings. The surface roughness, the adhesion force between the PTFE coatings and the carbide substrate, and the micro-hardness of the coated carbide were also evaluated. Additionally, the friction and wear behaviors were assessed through dry sliding friction tests against WC/Co balls. The test results indicated that while the PTFE-coated carbide exhibited a rougher surface and reduced micro-hardness, it also demonstrated a significant reduction in surface friction and adhesive wear. These findings suggest that the PTFE coatings enhance the overall wear resistance of the carbides. The lower surface hardness and shear strength of the coatings influenced the friction performance, leading to specific wear failure mechanisms, such as abrasion wear, coating delamination, and flaking. Overall, the deposition of PTFE coatings on carbide substrates presents a promising strategy to enhance their friction and wear performance. This approach not only improves the durability of carbide materials but also offers potential applications in industries where reduced friction and wear are critical for performance. [ABSTRACT FROM AUTHOR]

The article presents the research on turning the titanium alloy Ti6Al4V with uncoated carbide blades and physically coated with PVD and chemically CVD. By examining the processed surfaces using the contact method, it was found that the chemically applied coating allows one to obtain the best 3D roughness. Using finishing cutting parameters and CVD-coated blades, it is possible to obtain a surface with a roughness of Sq at the level of 0.7 μm and Sz 2 μm. Cutting force tests have shown that applying coatings to the cutting blade increases the total cutting force by approximately 20%. Additionally, on the basis of microscopic observations, it was found that thermal and adhesive wear occurs on the surfaces of coated blades. Tool coatings have no influence on the shape of the chips produced. The grey relational analysis performed showed that the best turning results for the Ti6Al4V alloy are obtained when using an uncoated HX insert with a feed of 0.08 mm/rev and a cutting speed of 70 m/min. The results of this analysis also indicate that the tested blades, which are not recommended for the machining of superalloys, should not be used to turn the Ti6Al4V alloy. [ABSTRACT FROM AUTHOR]

NiTi smart alloys are known for their characteristic shape memory behavior. The current work focuses on the physical and mechanical characterization of Ni(50−X)Ti50FeX shape memory alloys prepared by the spark plasma sintering (SPS) process and their dependence on the concentration of Fe. The physical characterization of the samples confirmed the presence of the FeNiTi phase along with the Ti- and Ni-rich phases. Enhanced mechanical properties were observed in 8 at. pct Fe samples, which contained secondary intermetallic phases such as Ti2Ni, Ni3Ti, Fe2Ti, and Ni4Ti3. Higher fraction of NiTi phase in the 8 at. pct Fe sample resulted in better shape memory properties while showing a higher friction coefficient. Ball on disk wear tests were done to identify the mechanisms contributing to the wear in the sintered sample. It is observed that the abrasive wear as well as the adhesive wear are the most prominent contributors for the surface material removal, and the dependence of characterization is observed with the variation of Fe content in NiTiFe alloy. [ABSTRACT FROM AUTHOR]

In this paper, ultrasonic surface rolling processing (USRP) is used to process GCr15 (AISI-52100), and a three-dimensional ultrasonic surface rolling processing simulation model is established by finite element method to analyze the influence mechanism of static pressure on residual stress. The design L9 orthogonal test studied the importance of USRP parameters on the surface roughness of GCr15 bearing steel. The influence mechanism of process parameters (feed, static pressure, and rotational speed) on the surface microhardness, microstructure, and wear resistance of GCr15 was also studied. The results show that when the process parameters 1400 N, 0.08, and 100 r/min (specimen A7) were selected for machining, the plastic deformation of the specimen was the most intense and the surface grains were refined, forming a grain refinement layer with a thickness of about 10 μm. The surface defects of the specimen are reduced, and the surface roughness is as low as 0.076 μm. The surface microhardness can reach up to 806.2 HV0.5. And the surface roughness, surface hardness, and residual stress increased by 12.56, 65.91, and 138.89%, respectively. After the USRP treatment, the coefficient of friction of the material is reduced, and the amount of wear is reduced by 30%. The wear mechanism also gradually changes from adhesive wear to abrasive wear. [ABSTRACT FROM AUTHOR]

In this study, the effect of intermetallic compounds (ICMs) on the tribocorrosion behavior of the 7075 aluminum alloy was investigated. ICMs play important roles in the tribocorrosion resistance and mechanism of the sample. In the as-received sample, micron-sized Mg2Si, Al23Fe4Cu, and nanosized MgZn2 induced pitting corrosion and acted as abrasive materials. Accompanying the re-dissolution of Mg2Si and the growth of MgZn2, the pitting resistance worsened and adhesive wear took place. Subsequently, MgZn2 precipitated along the grain boundaries, which resulted in intergranular corrosion and aggravation of adhesive wear. [ABSTRACT FROM AUTHOR]

Highlights The characterization of S. persica (Salvadora persica) extract, which involved evaluating its antibacterial activity, demonstrated the extract's strong efficacy. Additionally, incorporating it into PMMA/HA showcased the composite's good antibacterial activity. The objective of this work is to evaluate how the incorporation of S. persica extract affects the wear resistance of the dental composite PMMA/HA, considering the critical importance of wear resistance in dental applications. The wear response of this biocomposite was tested against an Alumina ball using a pin‐on‐disc tribometer. Initially, the hydroxyapatite (HA) micro particles demonstrate a remarkable influence on wear behavior when incorporated at an optimal percentage (10%wt). This optimal inclusion rate not only significantly increases the wear rate but also instigates a shift in the wear mechanism, favoring abrasive wear while minimizing adhesive wear comparing to PMMA. The addition of the extract nanoparticles to the composite PMMA/HA decreases the wear rate except the composite containing 10 wt% of each filler. Additionally, it introduces adhesive wear, in addition to the existing fatigue and abrasion wear. Thus, the composite PMMA/HA could accommodate up to 10 wt% of the S. persica extract as the optimal percentage that provides antibacterial activity to this biocomposite without exhibiting a deterioration in wear performance. The evaluation of the effect of incorporating S. persica extract, which provides antibacterial activity, on the wear resistance of the PMMA/HA dental composite generally demonstrates a reduction in this property. The addition of S. persica extract introduces adhesive wear in addition to the fatigue and abrasion wear already present in the PMMA/HA composite. The composite PMMA/HA can accommodate up to 10 wt% of S. persica extract without compromising its wear performance. [ABSTRACT FROM AUTHOR]

Titanium alloys are applied in oil and gas development and transportation to improve conditions because of their high specific strength and corrosion resistance. However, the disadvantage of poor wear resistance has become an obstacle to developing titanium alloys. The friction and wear properties of pure titanium TA3 and titanium alloy TA10 were tested under different loads and different friction forms using a reciprocating friction and wear tester. Moreover, the erosion resistance of pure titanium TA3 and titanium alloy TA10 was studied using a gas–solid erosion tester. The results show that the wear rate of TA3 and titanium alloy TA10 increases with increasing friction load. Under a load of 50 N, the mass losses of TA3 under dry friction and wet friction were 0.0013 g and 0.0045 g, respectively, while the mass losses of TA10 were 0.0033 g and 0.0046 g, respectively. While the load increased to 70 N, the mass loss of TA3 was even greater, reaching 0.0065 g, and the mass loss of TA10 was 0.0058 g. The wear forms of TA3 and TA10 include abrasive wear, adhesive wear and oxidation wear. The joint action of various friction forms leads to the loss of materials. Under the simulated working conditions, the erosion rates of TA3 and TA10 were 1.01 × 10−3 g/s and 0.94 × 10−3 g/s. The erosion mechanism is the same, including plowing, indentation and cracking. [ABSTRACT FROM AUTHOR]

Laser process parameters directly impact the quality of cladding, and selecting appropriate parameters can yield optimal microstructure and properties. To enhance the wear resistance of 316L stainless steel, an Inconel 718 coating was applied to the steel surface. The effects of different laser scanning speeds on the structure of the coating were examined. The phase composition, element distribution, microstructure, hardness, and wear resistance of the coating were also analyzed. The results showed that at different laser scanning speeds, the coating phases consisted of γ-(Fe, Ni) solid solution, Ni3Nb, (Nb0.03Ti0.97) Ni3, and MCX (M = Cr, Nb, Mo). At scanning speeds of 1.5, 2, and 2.5 mm/s, the average microhardness of the coating was 530.4, 604.6, and 593.2 HV0.2, and the wear rates were 5.85 × 10−5, 2.97 × 10−5, and 8.53 × 10−5 mm3∙N−1∙m−1, respectively. The coating exhibits the best performance at the laser scanning speed of 2 mm/s. The coating transitions from equiaxed crystals at the upper part to dendritic, cellular, columnar, and planar crystals near the bonding zone. The wear mechanisms observed are abrasive wear and adhesive wear. [ABSTRACT FROM AUTHOR]

AlCoCrFeNiTi0.5 high entropy alloy (HEA) coating with high hardness and excellent wear resistance was deposited on TC4 surface by electron beam cladding, and the process parameters, microstructure and properties of the coating were studied. The analysis shows that the microstructure of HEA coating is composed of dendritic (DR) and interdendritic (IR) phases. The IR phase, which is mainly composed of Fe and Cr, is confirmed to be BCC solid solution, while the DR phase is FCC solid solution with AlNi2Ti (or AlCo2Ti) structure. The grain orientation of the HEA coating is random, without obvious texture. Hardness gradually decreases from the upper part area of the HEA coating to the inner of the TC4 substrate. The hardness curve in the HEA coating region has some fluctuations, but the fluctuations are small, indicating a homogeneous microstructure. The average hardness of the HEA coating is 796.18 HV0.2, which is about 2.6 times that of the TC4 substrate. The HEA coating exhibits a higher coefficient of friction (COF) compared to the TC4 substrate. The average COF of HEA coating and TC4 substrate in the stable stage are 0.57 and 0.48, respectively. Wear loss of the HEA coating is 0.0657 mm3, about one tenth of that of TC4 substrate (0.6112 mm3). The hardness of the HEA coating is high, no obvious furrow is found, and its wear mechanism is considered to be a mixture of adhesive wear and oxidation wear. [ABSTRACT FROM AUTHOR]

N-doped CoCrFeNiMn high entropy alloy coating (N-HEA) was prepared on Ti-6Al-4V alloy by high-velocity oxygen fuel (HVOF) spraying coupled with double glow plasma nitriding. The results show that the CoCrFeNiMn high entropy alloy coating (HEA) is mainly composed of single CoCrFeNiMn face-centered cube (fcc) phase with a little MnCr2O4 spinel phase, and the thickness is approximately 200 μm. After plasma nitriding, the surface morphology of the coating is reconstructed, changing from the molten and semi-melted coral-like structure to cauliflower-like structure, while the surface roughness and the thickness have no significant change. The phase composition of the N-HEA coating has no obvious change, and the N mainly exists as interstitial atoms in solid solution. The microhardness of the HEA coating is highly significantly higher than Ti-6Al-4V alloy, and it is further increased by 45% after plasma nitriding. The friction coefficient of N-HEA coating is as low as 0.38, and the wear rate is 1.283 × 10−4 mm−3N−1 min−1, which is 53 and 72% lower than those of the HEA coating and the Ti-6Al-4V alloy, respectively. Both the wear mechanism of the N-HEA and HEA samples against GCr15 steel ball are mainly adhesive wear, while more Fe elements are transferred from the GCr15 steel ball onto the surface of the N-HEA sample. [ABSTRACT FROM AUTHOR]

Ni60WC coatings were prepared on 45 steel by laser cladding with different scanning speeds, and the effects of laser scanning speed on the microstructure, phases and hardness were analyzed using a super-depth field microscopy, x-ray diffraction and microhardness tester. The tribological performance of Ni60WC coatings fabricated at the different scanning speeds was analyzed using a ball-on-disc wear tester, and the wear mechanism was discussed. The results show that the hardness of Ni60WC coating fabricated at the laser scanning speeds of 50, 60 and 70 mm/s is 1475.0 ± 129, 1564.9 ± 117 and 1527.2 ± 140 HV0.5, respectively, showing the coating hardness fabricated at the laser scanning speed of 60 mm/s is the highest. The average coefficients of friction of Ni60WC coatings fabricated at the laser scanning speeds of 50, 60 and 70 mm/s are 0.297, 0.344 and 0.440, respectively, and the corresponding wear rates are 949.2, 854.6 and 881.4 μm3s−1N−1, respectively, showing that the wear resistance of Ni60WC coating fabricated at the laser scanning speed of 60 mm/s is the best. The wear mechanism of Ni60WC coating is combined of abrasive wear and adhesive wear, which is attributed to the WC particle with the high hardness. [ABSTRACT FROM AUTHOR]

Wear and erosion wear represent primary failure mechanisms in flow passage components, and proactive preventive maintenance can effectively extend their service life. This study investigates the utilization of laser metal deposition technology for the additive manufacturing of 17-4PH stainless steel (17-4PHss) followed by solid solution aging treatment. Structural transformations before and after the solution aging treatment, along with the dry wear and erosion wear properties of 17-4PHss post-heat treatment, were examined. During the heat treatment process, the solid solution treatment fully transformed the microstructure to martensite, alleviating the stress generated by the additive process, and refined the microstructure to 0.64 μm. The subsequent aging treatment further refined the grains, ultimately reducing the grain size from 0.68 μm in the additive state to 0.62 μm. Compared to traditional casting, the grain size of 17-4PHss was reduced by 6.83%. Additionally, NbC was uniformly distributed in the sample, playing a secondary phase strengthening role, resulting in high microhardness (455.5 HV0.2). Simultaneously, the solid solution-aged (SSA) sample exhibited robust wear resistance, manifesting abrasive wear at low loads. With increasing load, a transition to abrasive wear and adhesive wear occurs, accompanied by oxidative wear and fatigue wear. At a 30 N load, the specific wear rate of the SSA sample decreased to 0.17 × 10−5 mm3/Nm, attributed to the more stable microstructure of the SSA sample under high loads. In the erosion wear test, the cumulative mass loss of the sample after heat treatment was the lowest (10.71 mg/m2h), with the erosion wear mechanism attributed to plastic deformation and micro-cutting. [ABSTRACT FROM AUTHOR]

In engineering applications, it is crucial to extend service life by reducing the coefficient of friction (COF) and wear rate to improve dry wear resistance. This work investigates the tribological properties of NiCrAlY-Cr3C2-Ti2SnC coatings with different Ti2SnC additions over a wide temperature range. Composite coatings with varying Ti2SnC concentrations were deposited onto TC4 titanium alloy substrates using atmospheric plasma spraying. Pin-on-disk wear tests were utilized to evaluate the tribological performance of the coatings, including the friction coefficient and wear rate, from room temperature to 800 °C. The wear mechanism of the coating was determined using SEM and a 3D profiler. The results demonstrate that the coating containing 30 wt.% Ti2SnC (NC-30TSC) exhibits the lowest friction coefficient (0.29) and wear rate (4.89 × 10−5 mm3·N−1·m−1) at 800 °C. The composite coatings containing Ti2SnC exhibited a decreased coefficient of friction and wear rate due to the high-temperature decomposition products of Ti2SnC, such as TiO2 and TiC. The wear mechanisms of the NC-30TSC coating were adhesive and fatigue wear at 300 °C, adhesive and oxidation wear at 600 °C, and oxidation wear at 800 °C. Additionally, the prefabricated cracks on the surface of the NC-30TSC coating healed after isothermal treatment, demonstrating excellent self-healing performance. [ABSTRACT FROM AUTHOR]

Massively carbon-supersaturated (MCSed) tool steel dies were developed to make galling-free forging products from titanium bar feedstocks in dry conditions without lubricating oils. Two types of tool steel dies were used, SKD11 and ACD56, following the Japanese Industrial Standard (JIS). The plasma-immersion carburizing process was employed to induce massive carbon supersaturation in two kinds of tool steel dies at 673 K for 14.4 ks. A pure titanium bar was upset in a single stroke up to the reduction of thickness of 70% using the MCSed SKD11 die. Very few bulging displacements of the upset bar proved that μ = 0.05 on the contact surface of the MCSed SKD11 die to pure titanium work. Two continuous forging experiments were performed to demonstrate that an in situ lubrication mechanism played a role to prevent the contact surface from galling to titanium works in both laboratory- and industry-scaled forging processes. After precise microstructure analyses of the contact surface, the free-carbon film formed in situ acted as a lubricating tribofilm to reduce friction and adhesive wear in continuous forging processes. The MCSed ACD56 dies were also used to describe the galling-free forging behavior of manufacturing eyeglass frames and to evaluate the surface quality of the finished temples. The applied load was reduced by 30% when using the MCSed ACD56 dies. The average surface roughness of the forged product was also greatly reduced, from 4.12 μm to 0.99 μm, together with a reduction in roughness deviations. High qualification of forged products was preserved together with die life prolongation even in dry manufacturing conditions of the titanium and titanium alloys. [ABSTRACT FROM AUTHOR]

Carbon fiber–reinforced polymer (CFRP) and titanium alloy have become the preferred materials for aviation equipment manufacturing due to their excellent mechanical and chemical properties. The high-precision hole-making technology of CFRP/titanium alloy–stacked structure is crucial for ensuring the connection performance of aviation main load-bearing components. However, the significant accumulation of cutting heat during this hole-making process can easily exacerbate tool wear and reduce connecting hole quality. The study developed a low temperature cold wind device based on the Coanda effect and conducted helical/inclined planetary milling hole experiments on CFRP/titanium alloy stacks with/without low temperature cold wind conditions on a rotary worktable for machine tool processing. The effects of cooling device on the machining temperature, milling force, tool wear, and hole quality of helical/inclined planetary milling were analyzed. The research results indicate that the continuous cooling and strong airflow impact of the low temperature cold wind device can significantly reduce the temperature during helical milling and inclined planetary milling, avoiding the serious adhesive wear and cutting edge breakage of the tool, reducing the tearing and burr of the CFRP hole exit and the ablation discoloration of the stacked interface, and lowering the hole wall roughness. As the machining process progresses, the low temperature cold wind device can maintain the cutting temperature at relatively low levels and slow down the wear rate of the milling cutter. [ABSTRACT FROM AUTHOR]

In order to improve the wear and frictional behavior of the aluminum metal matrix composites, carbon nanotube, and fly ash were added as reinforcements. Powder metallurgy technique was used to fabricate the hybrid metal matrix composites. Experimentations were carried out using pin on disc type wear test rig. The analyzed experimental results showed that, in comparison to the pure aluminum and mono reinforcement combination, the wear loss and coefficient of friction of hybrid metal matrix composites were greatly reduced. It was noted that compared to pure aluminum wear loss was decreased to 89.58%, 86.97%, 83.3% by adding 0.25, 0.5, 0.75 wt% carbon nanotube (CNT), respectively. By the addition of 4, 8 and 16 wt% FA to pure Al wear loss was decreased to 83.85%, 89.58%, and 78.12%, respectively. It was also noted that compared to Al/8 wt% FA mono reinforced composites, wear loss was decreased to 77%, 71.26%, and 53.22% with the addition of 0.25, 0.5, 0.75 wt% CNT, respectively. With the addition of 4, 8, 16 wt% FA, wear loss decreased to 81%, 88%, and 75% over Al/0.25 wt% CNT composites, respectively. The microstructural study of the worn‐out surfaces revealed low abrasive and adhesive wear by the presence of carbon nanotubes and fly ash in aluminum metal matrix. The reinforcing mechanisms of the wear and frictional properties were also discussed. [ABSTRACT FROM AUTHOR]

Improving the surface performance and service life of 60Si2Mn steel is an important issue in agricultural machinery. A FeCrV15 coating layer may exhibit excellent performance in wear resistance. This research focuses on studying the microstructure and wear resistance of the FeCrV15 coating layer at various scanning speeds through laser cladding. Microstructure, phase distribution, surface hardness, and wear resistance of the coating layers are analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), a microhardness tester, and laser confocal microscopy. The results indicate that the FeCrV15 alloy coating consists of γ-Fe, V8C7, and Cr7C3. The microhardness of the FeCrV15 coatings increases with the increase in the scanning speed. At a scanning speed of 8 mm/s, the highest microhardness reaches 727.5 ± 27 HV, approximately 2.5 times higher than the substrate. The friction and wear test of the coating is conducted using a 4 mm diameter Si3N4 ball grinding pair. The coatings prepared at different scanning speeds exhibit lower average coefficients of friction and wear rates compared to the substrate. Both the average coefficient of friction and wear rate decrease with increasing scanning speed. At a scanning speed of 8 mm/s, the lowest average coefficient of friction and the lowest wear rate were observed. The main wear mechanisms of the coating are oxidative wear and adhesive wear, with a small amount of abrasive wear. [ABSTRACT FROM AUTHOR]

The tribological phenomena concerning the lubrication regime change (LRC) during bulk metal forming are comprehensively studied. A multi-step cold forward extrusion process shows the evolution of LRC and reveals the shortcomings of the traditional Coulomb friction law. The previous works of the specific author's research group on friction are reviewed, focusing on the LRC during bulk metal forming. Various LRC phenomena from various examples are revealed. It has been found that the drawing and forward extrusion processes are vulnerable to LRC because of significant sliding motion at the material–die interface, and that when the strain hardening of the material is slight, the influence of friction increases, and as a result, the influence of LRC increases excessively. The new findings also include the impact of LRC on the macroscopic phenomena of the process and the reason for the sharp increase in friction coefficient via LRC, which is validated by the work of Wilson. This paper aims to make engineers and researchers think much of the tribology with lubricant in bulk metal forming with a focus on the dependence of tribological phenomena on the state of the lubricants and the irrationality of traditional friction law, especially in the forging of materials with a low strain hardening capability. [ABSTRACT FROM AUTHOR]

Fluoroelastomer (FKM) undergo various degrees of degradation in a gamma‐irradiated environment, leading to changes in their mechanical and tribological properties. In this paper, changes in the properties of FKM were investigated for six different doses. Fourier transform infrared‐atomic absorption spectroscopy (FTIR‐ATR) results show that FKM samples undergo dehydrofluorination and oxidation reactions during irradiation, resulting in the formation of C=C, C=O, and ‐OH functional groups. The results of the swelling test showed that the degree of cross‐linking of the FKM specimens increased with increasing irradiation dose. Mechanical test results show that the fracture mechanism of FKM specimens gradually evolves from ductile fracture to brittle fracture with the increase of irradiation dose. Its tensile strength reaches its maximum at an irradiation dose of 1000 kGy, and the modulus of elasticity becomes larger with increasing irradiation dose. The results of wear tests show that the average coefficient of friction of FKM specimens first decreases, reaches a minimum at 500 kGy, and then gradually increases. The amount of wear increases with increasing irradiation dose. The wear mechanism of FKM specimens is abrasive wear at 0–500 kGy, adhesive wear at 1000 and 2000 kGy, and fatigue wear at 3000 kGy. Highlights: FKM was irradiated by gamma‐ray with a total dose of 3000 kGy.Dehydrofluorination and oxidation reactions occur during irradiation.Increased cross‐linking leads to changes in mechanical properties.The wear mechanism of FKM with different doses has been investigated. [ABSTRACT FROM AUTHOR]

Considering their affordability and high strength-to-weight ratio, lightweight aluminium alloys are the subject of intensive research aimed at improving their properties for use in the aerospace industry. This research effort aims to develop novel hybrid composites based on AA 2014 alloy through the use of liquid metallurgy stir casting to reinforce dual ceramic particles of Zirconium Diboride (ZrB2) and Boron Carbide (B4C). The weight percentage (wt%) of ZrB2 was varied (0, 5, 10, and 15), while a constant 5 wt% of B4C was maintained during this fabrication. The as-cast samples have been assessed using an Optical Microscope (OM) and a Scanning Electron Microscope (SEM) with Energy Dispersive Spectroscopy (EDS). The properties such as hardness, tensile strength, and wear characteristics of stir cast specimens were assessed to examine the impact of varying weight percentages of reinforcements in AA 2014 alloy. In particular, dry sliding wear behaviour was evaluated considering varied loads using a pin-on-disc tribotester. As the weight % of ZrB2 grew and B4C was incorporated, hybrid composites showed higher hardness, tensile strength, and wear resistance. Notably, the incorporation of a cumulative reinforcement consisting of 15 wt% ZrB2 and 5 wt% B4C resulted in a significant 31.86% increase in hardness and a 44.1% increase in tensile strength compared to AA 2014 alloy. In addition, it has been detected that wear resistance of hybrid composite pin (containing 20 wt% cumulative reinforcement) is higher than that of other stir cast wear test pins during the whole range of applied loads. Fractured surfaces of tensile specimens showed ductile fracture in the AA 2014 matrix and mixed mode for hybrid composites. Worn surfaces obtained employing higher applied load indicated abrasive wear with little plastic deformation for hybrid composites and dominant adhesive wear for matrix alloy. Hence, the superior mechanical and tribological performance of hybrid composites can be attributed to dual reinforcement particles being dispersed well and the effective transmission of load at this specific composition. [ABSTRACT FROM AUTHOR]

This paper investigated the FeCoCrNiAl high-entropy alloy on H13 steel, prepared using laser cladding, to improve the elevated-temperature wear resistance of the alloy. The results revealed that FCC and BCC phases, in terms of the coating, produced a large dislocation density. The coating exhibited a columnar and equiaxed crystal microstructure. With the comprehensive effects of fine-grain strengthening, solid solution strengthening, and dislocation strengthening, the average hardness of the coating (500 HV0.1) was improved by 150% compared with that of H13 steel (200 HV0.1). The wear experiments were conducted at 623 K, 723 K, and 823 K. Compared with H13 steel, the wear volume of the coating decreased by 59.20%, 70.79%, and 78.20% under different temperatures. The wear forms impacting the coating were mainly abrasive wear and oxidation wear. However, H13 steel presented adhesive wear and fatigue wear, in addition to abrasive wear and oxidation wear. [ABSTRACT FROM AUTHOR]

The aerospace industry has made extensive use of titanium alloy material due to its exceptional qualities, which include high strength, low weight, and resistance to corrosion. However, these qualities also pose challenges for the material's processing. This article examined the coated end mills for Ti6Al4V milling. First, an analysis was conducted on the solubility of Ti and Si elements. It was discovered that W and Co elements were far more soluble in Ti than Si and Zr elements, which could effectively stop element diffusion. Next, the base's composition was planned. It was discovered that when the amount of Al increased, the base's surface roughness increased, while its hardness and elastic modulus decreased. The binding force between the substrate and the base was greater at a 50:50 Ti:Al ratio. The H3/E2 was about 0.23 and the surface roughness was about 0.15 μm. TiSiN and TiSiN/ZrN functional layer properties were also examined. When Zr was added to TiSiN/ZrN coating, it improved the coating's hardness and elastic modulus, increased density, and decreased surface roughness and friction coefficient when compared to TiSiN coating. There was an increase in hardness by 8.09% and an increase in elastic modulus by 9.65%. The average coefficient of friction decreased from 0.315 to 0.299. Lastly, an analysis of the initial and intermediate tool wear was done using the Ti6Al4V milling experiment. It was discovered that adding Zr element could successfully extend the tool's cutting life by preventing adhesive wear. [ABSTRACT FROM AUTHOR]

Bandsaw blades are typical band-shaped cutting tools that are characterized by their low stiffness and micro-level cutting depth, resulting in distinct wear mechanisms compared to rigid cutting tools. In this study, the wear curve and wear mechanisms of the bandsaw tooth during the bandsawing of Cr12MoV cold-working steel were investigated. The tool life was divided into two stages: a rapid wear stage (Stage I) and a homogeneous wear stage (Stage II). In Stage I, the wear was dominated by chipping, although multiple wear mechanisms were found due to their relatively low manufacturing accuracy compared to rigid cutting tools, which resulted in remarkable differences in the cutting depth of each tooth. In Stage II, abrasive and adhesive wear were the primary wear mechanisms instead of chipping, which was related to the microstructure of Cr12MoV. Furthermore, methods for increasing bandsaw performance were proposed, based on the tooth wear mechanisms. [ABSTRACT FROM AUTHOR]

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Lightweight materials with better resistance to sliding wear are prominent candidates for automobile brake drums, clutch pads and cylinder block applications to facilitate fuel economy. This attempt is reserved to cater to materials with higher tribological quality needs. Less dense foamy pumice stone particles were involved in three different percentages (5, 10, and 15 wt%) to reinforce lightweight AZ31 Mg alloy. A stir-assisted squeeze casting technique was pursued to process the composite and refine the grain structure. A phase detection, elemental mapping and microstructure study were done through X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM), respectively. An experimental dry sliding wear scrutiny was administered using a pin-on-disc apparatus by considering: (i) ambient and elevated temperature environments and (ii) three different levels of loads. The results reveal a significant drop in wear loss and a frictional coefficient for 15% pumice-loaded composite than the base alloy. Post-wear examination acknowledges the fact that the ambient temperature wear is governed by adhesive-abrasive wear and high temperature is by abrasive wear mechanisms. Worn-out scrutiny authenticates the presence of oxide layers and their role in lubrication. A comparative study with previous works upholds the novel magnesium composite is the right candidate for the mentioned automobile applications.

AbstractA laser cladding technique was employed to produce a Fe50-XMn30Co10Cr10NbX (X = 2.5, 5, 7.5, 10at%) high entropy alloy coating. This study delved into the influence of Nb concentration on the coating’s phase constitution, microstructural features, hardness, and wear resistance. The high entropy alloy coating exhibited a multifaceted structural composition, encompassing FCC (Face-Centered Cubic), HCP (Hexagonal Close-Packed), and BCC (Body-Centered Cubic) structures, along with the presence of Laves phase. Notably, the incorporation of Nb led to an augmentation in the Laves phase and modifications within the microstructure. The hardness of the cladding layer is higher than that of the substrate. With the increase of Nb content, the hardness of the cladding layer increases first and then decreases; the average hardness of the Fe42.5Mn30Co10Cr10Nb7.5 cladding layer is the highest, the maximum hardness is 429.8Hv, and the average hardness is 382.3Hv. The friction coefficient and weight loss of the cladding layer decreases first and then increases with the increase of Nb content. The friction coefficient and weight loss of the Fe42.5Mn30Co10Cr10Nb7.5 cladding layer are the smallest, which are 0.0132 g and 0.5974, showing the best wear resistance. The wear types of high entropy alloy cladding layer are both adhesive wear and abrasive wear. The addition of Nb into high entropy alloy will form the Laves phase, which can improve the mechanical properties of high entropy alloy. [ABSTRACT FROM AUTHOR]

This study investigated the microstructure and tribological performance of TiO 2 coating prepared through the plasma-spraying of TiO 2 on an aluminum alloy (ZL109) surface. Box–Behnken design was employed to calculate the optimal spraying parameters (spraying current: 439 A, spraying voltage: 129 V, and Ar flow rate: 117 m3/h). High-temperature tribological characteristics (T = 120 °C) were examined under varying loads (F = 100 N, 120 N, and 140 N). The scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis results revealed that the coating porosity decreased from 3.31 % to 0.31 % with the increase in the spraying voltage from 120 V to 130 V. Both powder and coating exhibited consistent elemental composition (Ti, O) and phase composition (TiO 2 , TiO, Ti 2 O 3). During the spraying process, part of the powder was oxidized. The average coefficient of friction of the coatings varied from 0.05 to 0.08, and as the load increased, the wear mechanism of the coating changed from abrasion to adhesive wear and oxidation. [ABSTRACT FROM AUTHOR]

In order to prepare coating with good friction and wear resistance at elevated temperature on the surface of hot-working tool steel, by using a CO2 laser, FeCrNiTiZr high-entropy alloy coating with different laser scanning speeds (360, 480 and 600 mm/min, respectively) was successfully fabricated by using laser cladding technology on the surface of H13 steel in this paper. Phase constitutions, microhardness, microstructure, and wear characteristics of FeCrNiTiZr coatings under different laser scanning speeds were analyzed. It was determined that 480 mm/min was the optimal laser scanning speed. The results showed that the coating at the scanning speed of 480 mm/min consists of a BCC phase with significant lattice distortion and high dislocation density; the crystal structure is cellular crystal and dendrite crystal. The coating demonstrates the highest microhardness (842 HV0.2), which is 4.2 times that of the substrate (200 HV0.2). Its average friction coefficients at room temperature and 823 K are approximately one-seventh and one-third of the substrate's, respectively, and its wear volume is reduced by about 98% and 81% under these conditions. Compared to the substrate, the coating underwent slight abrasive wear, adhesive wear, and oxidative wear at both room temperature and 823 K. In contrast, the substrate underwent severe abrasive wear, adhesive wear, oxidative wear, and even fatigue wear. [ABSTRACT FROM AUTHOR]

Difficult-to-machine materials are characterized by high hardness, strength, and anisotropy. During machining, tools can suffer from adhesion, abrasion, material detachment, and high cutting temperatures. These factors result in severe adhesive wear, abrasive wear, oxidative wear, and diffusion wear. Intense tool wear leads to more burrs, delamination, chipping, and dimensional errors in the parts. It significantly increases production costs and reduces machining efficiency. Therefore, further research into tool wear is of great importance. This paper reviews the characterization and monitoring of tool wear, the morphology and mechanism of wear, and measures for improving wear, with a focus on tool wear in the machining of difficult-to-machine materials. Through a comprehensive review of existing research findings, this work offers a perspective on the investigation of tool wear, providing an effective guide for future research. And it is of great significance to improve tool life and cutting quality. [ABSTRACT FROM AUTHOR]

Copper‐based metal–organic frameworks is anticipated to find applications in the field of friction materials owing to its plentiful surface‐active groups and distinctive framework structure. In this study, copper‐based metal–organic frameworks was synthesized through ultrasound‐assisted method and incorporated alone into carbon fiber reinforced epoxy composites or together with SiO2 nanoparticles towards the goal of improving the composites' friction and wear properties. It is revealed that copper‐based metal–organic frameworks alone cannot improve the friction and wear of carbon fiber reinforced epoxy composites simultaneously. The combination of copper‐based metal–organic frameworks and SiO2 nanoparticles was more effective in enhancing both the mechanical and tribological properties of studied composites. The composite material exhibits a friction coefficient of 0.104 under the specified test conditions of 10 MPa and 3.75 m/s. Additionally, the specific wear rate is impressively low, measuring only 5.64 × 10−7 mm3 N/m. Through morphological and chemical analysis on the worn surfaces and transfer films, the functioning mechanism of copper‐based metal–organic frameworks in modifying the mechanical and tribological properties was discussed. It was discovered that a tribological synergy exists between short carbon fibers, copper‐based metal–organic frameworks, and SiO2 fillers, leading to a shift in the wear mechanism of the composite materials from abrasive wear to adhesive wear. Concurrently, a shear‐prone transfer film forms on the surface of the counter steel surfaces. Findings of the present study pave a new route of designing high performance epoxy based tribo‐composites by using metal–organic frameworks. Highlights: Cu‐BDC nanosheets were synthesized using ultrasound‐assisted techniques and incorporated as tribological fillers in EP composites.The combined use of Cu‐BDC, SiO2, and SCF fillers synergistically enhances the mechanical and tribological properties of EP composites.The composite material exhibits a friction coefficient of 0.104 under the specified test conditions of 10 MPa and 3.75 m/s, the specific wear rate is impressively low, measuring only 5.64 × 10−7 mm3N/m.During the sliding friction process of the composite materials, Cu‐BDC and SiO2 play a crucial role in reducing SCF pull‐out wear through their anchoring effect.The dynamic coordination bond structure of Cu‐BDC contributes to the formation of uniform and continuous transfer films on counter metal surfaces. [ABSTRACT FROM AUTHOR]

Archard’s wear law encounters challenges in accurately predicting wear damage and volumes, particularly in complex situations like asperity–asperity collisions. A modified model is proposed and validated, showcasing its ability to predict wear in adhesive contacts with better accuracy than the original Archard’s wear law. The model introduces an improved wear coefficient linked to deformation energy, creating a spatially varying relationship between wear volume and load and imparting a non-linear characteristic to the problem. The improved wear model is coupled with the Boundary Element Method (BEM), assuming that the interacting surfaces are semi-infinite and flat. The deformation energy is calculated from the normal contact pressure and displacements, which are the common outputs of BEM. By relying solely on these outputs, the model can efficiently predict the correct shape and volume of the adhesive wear particle, without resorting to large and often slow models. An important observation is that the wear coefficient is expected to increase based on the accumulated deformation energy along the direction of frictional force. This approach enhances the model’s capability to capture complex wear mechanisms, providing a more accurate representation of real-world scenarios. [ABSTRACT FROM AUTHOR]