Medically implantable metallic stents serve as a crucial interventional treatment for vascular stenosis; however, in-stent restenosis persists at a rate of 15%–30% following implantation, substantially compromising therapeutic outcomes. In this study, a composite surface modification strategy combining U-shaped microtextures and DMSO molecular modification was developed to fabricate novel anticoagulant stents capable of suppressing thrombus regeneration. The TC4 titanium alloy (Ti-6Al-4V) vascular stents containing microtextures on the inner surface were prepared by the whole process of pulsed laser etching, continuous laser welding, and infrared laser engraving. In contrast, the DMSO molecular coating was prepared by the composite chemical modification technique to obtain the modified vascular stents with hydrophobic properties, and the exposure of the two CH₃ groups was the reason for the enhanced hydrophobic properties. The results of flow cytometry tests using FITC-CD41 antibody and PE-CD62P staining showed that the platelet activation rate on the surface of the microtextured composite DMSO-modified stents was significantly reduced, the CD62P expression rate decreased to 7.74%, and the amount of platelet adhesion was reduced considerably. Hemodynamic analysis demonstrated that, compared to smooth stents, the microtextured stent exhibited reduced shear stress oscillation amplitude along the blood flow wall. The low-shear-stress area (<0.5 Pa) measured 33.855 mm², a 17.5% reduction, accompanied by effective inhibition of platelet activation.

Cemented carbides, composed of hard carbide phases and metallic binders, are extensively employed in extreme tribological environments involving high-load dry friction, elevated-temperature cutting, erosive particle flows, cyclic impact, micro-vibration, and corrosive media. In response to increasing performance demands under such complex service conditions, this review systematically evaluates the tribological behaviors and failure mechanisms of cemented carbides under adhesive, abrasive, fatigue-induced, oxidative, erosive, fretting, and corrosion-induced wear conditions. The critical influence of carbide phase type and grain scale, binder chemistry and mean free path, and microstructural configuration on interfacial degradation pathways is clarified, establishing a structure-driven, mechanism-based framework that links microstructural descriptors with damage evolution and dominant wear modes. On this basis, multi-scale strengthening strategies-including compositional design, microstructural refinement, binder phase optimization, grain-scale engineering, PVD/CVD thin films, and surface texturing-are summarized and comparatively assessed with respect to their effectiveness across varied tribological conditions. Finally, emerging trends are discussed, with emphasis on multi-field coupling mechanisms, cross-scale wear modeling, low-Co and environmentally benign binder systems, powder-metallurgy-enabled, and adaptive surface engineering. This review provides theoretical guidance and design strategies for achieving high reliability and long-term service durability of sintered cemented carbides in extreme tribological environments.

Supramolecular gel holds great potential in engineering applications as lubricant. However, pure organic network of the gel limits their rheological and lubrication performance. Here, we report a nanoporous materials-functionalized supramolecular composite gel lubricant by incorporating polymer brush-grafted metal-organic frameworks (MOFs) nanoparticles (NPs) as nano additive. The composite gel was produced by encapsulating poly(lauryl methacrylate) (PLMA) polymer brushes functionalized UiO-67 (UiO-67@PLMA) NPs in 500 SN base oil of a 3D network formed by 12-hydroxystearic acid (12-HSA) through hydrogen bonding and van der Waals (vdW) interactions. The addition of UiO-67@PLMA NPs largely improved the thermal and rheological properties of the 12-HAS/500 SN gel, and the storage modulus and loss modulus increasing significantly. Tribological tests showed that incorporating 0.40 wt.% UiO-67@PLMA NPs into the composite gel reduced the coefficient of friction and wear volume by 45.68% and 86.85%, respectively. Furthermore, the UiO-67@PLMA gel demonstrated remarkable tribological performance under challenging conditions, such as 400 N, 65 Hz, and 160 °C. The outstanding lubrication performance of the supramolecular composite gel arises from shear-triggered release of base oil and nanoadditves, acting as nano ball-bearings and promoting protective film formation.

Classical hydrodynamic lubrication simulation solves Reynolds equation to unveil the lubrication pressure and film thickness distributions, yet it overlooks the latent high-level representations buried beneath the lubrication data. While deep learning has illustrated that the mining of high-level representations helps to generate desired outputs from input prompts, the lubrication research, however, has not fully exploited generative deep learning in lubrication prediction and generation. Here, we propose to adopt a deconvolutional neural network to learn the latent representations in hydrodynamic lubrication data and directly generate 2D lubrication scenario from the given working condition without solving any governing equation. Compared to classical method, our approach can output the distribution of lubrication pressure and film thickness in less than 0.1 s on a personal computer and be extended to more complicated scenarios including cavitation.

During sliding contact, asperities may undergo either ductile smoothing or brittle fracture, producing debris. A critical junction scale, d∗, governed by material properties, dictates this transition. Previous studies using Molecu-lar Dynamics (MD) simulations with tunable interatomic potentials revealed this scale under quasi-static conditions—fixed temperature and low sliding velocities. Here, we extend that work to investigate how temperature and sliding velocity influence the ductile-to-brittle transition at the asperity level. Material properties governed by short-range atomic interactions, such as stiff-ness and surface energy, remain relatively constant with temperature. In con-trast, shear strength, influenced by longer-range interactions, decreases with rising temperature, promoting a brittle-to-ductile shift in asperity behavior. Incorporating temperature-dependent shear strength into the d∗ expression successfully predicts the lower bound of the transition. However, capturing the upper bound requires an additional term to account for ductile fracture energy.<br />At higher sliding velocities, a new brittle failure mode emerges: instead of a single crack forming at the asperity base, multiple dynamically propagating cracks develop, resulting in fragmented debris.<br />Finally, long-timescale MD simulations of rough-on-rough contact under adi-abatic conditions reveal how interface heating influences wear during ex-tended sliding. Regardless of velocity, asperities initially fracture and gener-ate debris that aggregates into a single rolling particle. This particle grows steadily until the surrounding material nears its liquefaction temperature, triggering collapse. These simulations reproduce known wear regimes: an early, high-wear running-in phase followed by a steady-state mild wear stage. Notably, tangential work, heat generation, and wear rate depend primarily on total sliding distance rather than velocity.

While amorphous carbon-based films are recognized for their efficacy in mitigating fretting wear, owing to the fact that tribopairs demonstrate divergent tribological responses under different fretting states, it remains essential to explore their friction-mitigation mechanisms across distinct fretting regimes and elucidate the evolutionary patterns of these regimes. This effort is critical to gaining a thorough and systematic insights into the fretting characteristics of amorphous carbon-based films. The running conditions fretting map was constructed via friction force-displacement curves, and the evolutionary relationship between the two fretting regimes was explored. Additionally, the wear mechanisms and friction-mitigation mechanisms under these two regimes were systematically investigated via advanced characterization techniques, including FIB-TEM, SEM, Raman spectroscopy, and XPS. Results show that increasing normal load shifts fretting regime toward partial slip regime, leading to a decreased friction coefficient and increased wear volume, dissipated energy, and tangential stiffness. Increasing displacement amplitude drives the fretting regime to evolve toward the slip regime, resulting in increased friction coefficient, wear volume, and dissipated energy, along with decreased tangential stiffness. Notably, an amorphous-nanocrystalline composite structure, in which iron oxides are encapsulated by graphitized carbon film, forms on the surface of counterpart balls in the slip regime. This structure exerts a pivotal effect on mitigating the friction coefficient and fretting wear. Furthermore, this work advances the fundamental understanding of the mechanisms governing the tangential fretting wear of DLC films, and offers valuable design guidance and a robust theoretical basis for alleviating fretting damage.

Although coating protection mechanisms are well understood for individual corrosion or wear conditions, tribocorrosion presents a unique challenge where synergistic interactions between mechanical friction and electrochemical corrosion accelerate coating degradation. Here, polyaniline microcapsules containing linseed oil, 2-mercaptobenzothiazole, and rhodamine B were <em>in-situ </em>loaded onto MXene nanosheets, and subsequently incorporated as multifunctional fillers into an epoxy coating. The tribocorrosion behaviors and the relevant mechanism of as-prepared coatings were evaluated <em>via</em> experiment characterization and molecular dynamics simulation. During the tribocorrosion process, the epoxy coating with pH/mechanical dual-responsive characteristics demonstrated the highest and most stable open-circuit potential (-0.44 V, ∆_OCP &lt; 0.09 V). Its coefficient of friction was the lowest (0.16), and the wear rate (1.8 × 10^-6 mm³/N·m) was reduced by two orders of magnitude compared to pure epoxy coating (3.68 × 10^-4 mm³/N·m). The Raman characterization of worn surface at different durations revealed that the signals of MXene and linseed oil at the friction interface gradually increased as the process progresses. The lubricating film composed of MXene and linseed oil progressively evolved from an initially fragmented and discontinuous state into a compact and well-organized composite network as the tribocorrosion duration increased. Furthermore, the intelligent tribocorrosion system possessed a 105% self-healing efficiency with significant fluorescence quenching, ultimately realizing a remarkably low tribocorrosion synergy coefficient of only 1.18. The combination of experimental analysis and molecular dynamics simulations revealed that the excellent tribocorrosion resistance originated from an active-passive protection mechanism constructed by the microcapsules@MXene network. The formation of a linseed oil/MXene-based lubricating film reduced interfacial friction, while the strong interfacial bonding improved resistance to mechanical deformation. This work designed an intelligent anti-tribocorrosion coating, expanding the strategy for protecting equipment surfaces in harsh environments.

This paper provides a thorough review of the advancements in acoustic emission (AE) technology used for monitoring journal bearings. Firstly, the AE sources generated from journal bearings under different lubrication regimes are classified and discussed. Subsequently, a comparative analysis of parametric analysis methods, waveform methods, and artificial intelligence recognition methods for the bearing AE signal analysis is conducted, highlighting their respective principles, pros and cons, and applications. Additionally, an overview of physical models representing AE waves on relatively sliding surfaces is provided from the wave generation mechanism perspective, and each model's applicable conditions are compared. Finally, an in-depth discussion is presented, and future research directions are highlighted.

This work explores the bi-stable behaviour of a frictional system susceptible to mode-coupling instability. The focus is placed on the variations of the energy flows at the contact, due to external perturbations, and the role of contact nonlinearities on the system dynamic response. A lumped parameter numerical model, incorporating contact nonlinearities, is developed, allowing transitions between sliding, sticking, and detachment contact conditions. While prestressed Complex Eigenvalue Analysis (CEA) allows to identify instabilities in the linearized frictional system, transient simulations were conducted to investigate the nonlinear system dynamics and the possibility to switch between two stable states (mode-coupling or stable sliding) by an external perturbation. The investigation of the bi-stable state has been carried out by performing an energy balance of the system, accounting for the exchanged mechanical energies at the contact, to highlight the key role of contact nonlinearities in driving the power flows at the origin of the different stable states and respective limit cycle. The findings underscore the critical role of contact nonlinearities in shaping the power flows at the contact interface, determining the transition between stable sliding and mode-coupling, providing further insights on the “fugitive” feature of mode-coupling instabilities.

Normal and tangential forces coexist between rough surfaces in engineering components under most operating conditions. Accurate measurement of contact forces (both normal and tangential forces) on rough surfaces is critical for the safety and stability of engineering equipment, as interfaces are typically discontinuous regions within mechanical systems. However, existing contact mechanics and electrical contact models mostly neglect tangential force effects, hindering their application to shearing behavior research and precluding the development of a contact force measurement methodology applicable to simultaneous normal and tangential force quantification. Inspired by the yield criterion for material damage, a contact mechanics model was developed that simultaneously accounts for the effects of normal and tangential forces. Then, a new principle of contact forces measurement is developed by correlating the contact resistance with the real contact area, which enables the simultaneous measurement of normal and tangential forces between rough surfaces based on the single contact resistance under steady-state contact conditions. By proposing a “static friction surface”, the static and dynamic friction stage is effectively differentiated, and the reasons for the sudden drop in friction force and the sudden increase in contact resistance during the static and dynamic transition stages are given. This work proposes a novel explanation for the friction mechanism in terms of mechanical deformation and electrical resistance changes.