Electropulsing (EP) treatment is widely recognized for accelerating precipitate strengthening in several alloy families including Al, Cu, Ni and stainless steel. In magnesium-rare earth (Mg-RE) alloys, the modulation of nano-precipitates in the microstructure exerts a critical influence on the mechanical properties of the materials. Herein, we systematically investigated the effect of EP treatment on the evolution of beta ' precipitates in Mg-Gd-Y-Zn-Zr alloys. Experimental results demonstrated that EP treatment could not effectively promote the precipitation of beta ' precipitates in the alloys of supersaturated solid salutation state. Conversely, in comparison with conventional heat treatment, EP treatment remarkably drove dramatic beta ' precipitate dissolution in 10 s at 160 similar to 180 degrees C caused by Joule heating, which is well below 250 degrees C required by conventional heat treatment. Meanwhile, the ultimate tensile strength was reduced from 348.5 +/- 3.6 MPa to 242.7 +/- 9.1 MPa, while the uniform elongation increased dramatically by 80 %, from 4.2 +/- 0.6 to 7.5 +/- 1.2 %, subsequent to the EP treatment. This counterintuitive behavior arises from the close proximity of precipitation and dissolution temperatures in Mg-RE alloys combined with EP-induced localized heating and defect/solute fluxes, which collectively bias transformation pathways toward dissolution rather than nucleation. Our findings revealed EP as a low-energy tool for rapid, spatially targeted softening and microstructural reset prior to re-aging. These insights broaden the functional space of EP from fast hardening to deliberate, state-dependent control of precipitation and dissolution in Mg-RE alloys.

To address the challenges of high friction coefficient and severe adhesive wear of titanium alloys under aqueous lubrication conditions, this study systematically investigated the layer-number effect of graphene oxide (GO) and its synergistic lubrication mechanism with ionic liquid using macroscopic tribological experiments, SEM, XPS, FIB-HRTEM, and molecular dynamics simulations. Experimental results show that the multi-layer GO/ionic liquid composite system reduces the friction coefficient to 0.0813 and the wear volume by 96.85 % compared to pure water, with a smooth worn surface exhibiting almost no adhesive features. FIB-HRTEM cross-sectional analysis further confirms the formation of a dense tribofilm approximately 15-24 nm thick on the titanium alloy surface. The study reveals that the number of GO layers can significantly affect lubrication performance: even in the absence of ionic liquid, multi-layer GO still significantly outperforms single-layer and few-layer GO; after the introduction of the ionic liquid, its enhanced interfacial adsorption and the improved dispersion of GO synergistically further enhance the lubrication performance. Molecular dynamics simulations reveal that multi-layer GO, through its easier interlayer sliding, denser hydrogen-bonding network, and more stable hydration layer, cooperates with preferentially adsorbed ionic liquid to jointly reduce the interfacial shear strength.

Using amino acid ionic liquids (Ser-TEA) as surface modifiers and citric acid (CA) the carbon source, ionised carbon quantum dots (Ser-CA/CQDs) of uniform size were successfully prepared in this study. They exhibited excellent dispersion stability and tribological performance in an ethylene glycol aqueous solution (EGaq), as revealed using a one-step pyrolysis method. Macroscopic experimental results show that adding 2.0 wt % Ser-CA/CQDs reduces the friction coefficient of EGaq from 0.16 to 0.128, and the wear scar volume decreases by 51.97 %, which is attributed to the formation of a hydration layer and tribofilm. Furthermore, molecular dynamics simulations at the microscopic level revealed that the weak interaction energy between Ser-CA/CQDs and the friction pair surface, combined with the "ball-bearing effect", significantly reduced frictional resistance. Further, the lubrication performance of EGaq improved with the formation of a carbon film and an interface with low shear strength. This process offers a novel atomic-level perspective for understanding and optimising the applications of nanolubricant additives.

In this study, threonine-based ionic liquid (IL)-decorated carbon quantum dots (CQDs), designated as Thr-CA/ CQDs, were successfully synthesised. By integrating macroscopic experiments with molecular simulations, we investigated for the first time the effect of branched structures on the antibacterial, anti-corrosion, and lubrication performance of IL-decorated CQDs from multiple perspectives. Tribological tests have revealed that under low loads, CQDs significantly enhance the friction reduction and anti-wear performance. Incorporating branched chains into serine-based ILs notably improve friction reduction but may partially diminish the corrosion resistance and anti-wear properties of IL-decorated CQDs (Ser-CA/CQDs). Additionally, IL-decorated CQDs partially inhibit the growth of E. coli. Simulations indicate that the higher energy gap of Thr-CA/CQDs decreases the electron transfer rate, limiting corrosion inhibition efficiency to 23.22 %. Moreover, Thr-CA/CQDs form strong hydrogen bonds and van der Waals interactions with base lubricant molecules, weakening their binding energy with the metal interface, leading to decreased wear resistance.

Carbon fiber reinforced polymer (CFRP) composites have been extensively utilized in the aerospace industry due to their exceptional mechanical and physical properties. However, the drilling process of carbon fiber composites is challenging due to their structural anisotropy, abrasiveness, and low thermal conductivity. To enhance processing quality, rotary ultrasonic longitudinal torsional vibration drilling (RULTVD) technology is employed for CFRP composite processing. Based on kinematics principles, a kinematics model of a single cutting edge is established, and the influence of separation characteristics on RULTVD machining is discussed. The effects of spindle speed, feed rate, and longitudinal-torsional amplitude on cutting force and hole export defects are investigated through experimental methods. The experimental results demonstrate that ultrasonic longitudinaltorsional drilling reduces the cutting force by 17.8 % compared to conventional drilling while decreasing the maximum delamination factor by 8.6 %. These findings validate that rotary ultrasonic longitudinal-torsional drilling significantly alleviates the processing challenges associated with carbon fiber reinforced composites while improving processing quality.

The precision inspection of rotary workpieces (e.g., cam-grooved and threaded components requiring rotational machining) poses critical challenges in industrial manufacturing. However, the complex geometries and challenges in central axis alignment make traditional methods prone to eccentricity and tilt errors, limiting their ability to achieve high precision in full-surface detection. Extending our prior work on dual non-coaxial optical path configurations, this study developed decoupled optical paths with independent projection and imaging modules, enabling flexible optical adjustment and a compact system design. Based on this foundation, an automated rotary scanning system was developed to achieve self-centering functionality and high-precision reconstruction of complex surface features. The proposed system achieves a repeatability of 0.27 mu m and a maximum indication error of 2 mu m, demonstrating high measurement precision and reliability. Experimental validation employing a smooth ring gauge and rotational shaft component demonstrated system feasibility for detecting internal and external surface features. The system enables precise measurement of detailed geometric characteristics, such as groove depth and width, while achieving an average sampling time of 0.2 s per acquisition during a full rotational scan. Compared to traditional methods, the proposed approach obviates the need for precision pre-alignment and doubles the measurement speed of similar line-structured light methods, significantly enhancing efficiency and reliability.

Silicon carbide fiber-reinforced silicon carbide ceramic matrix composites (SiCf/SiC composites) are widely used in aerospace, defense, and transportation applications because of their excellent properties, such as high hardness, light weight, high-temperature resistance, and wear resistance. However, the anisotropic, heterogeneous, and hard-and-brittle nature of SiCf/SiC composites poses challenges for their high-efficiency and high-quality machining. In this study, the tool trajectory, cutting force characteristics, axial thrust force, hole entrance damage, hole diameter accuracy, and hole wall roughness during both longitudinal–torsional ultrasonic vibration drilling (LTUVD) and conventional drilling (CD) of SiCf/SiC composites were investigated. The results indicate that, compared with CD, LTUVD of SiCf/SiC composites reduces the axial thrust force by 35.7

This study systematically investigates the synergistic lubrication mechanism of ionic liquid and nanodiamond in aqueous solution for titanium alloys, focusing on the effect of ionic liquid concentration. The nanolubricant with 0.1 % ionic liquid and 1.0 % nanodiamond has a friction coefficient reduced to below 0.1. In comparison to pure water lubrication, the mean friction coefficient is reduced by 67.96 %, and the wear volume is decreased by 95.31 %. Its excellent lubricating properties stem from the preferential adsorption of low-concentration ionic liquid onto the friction pair surface to form a thin titanium oxide tribochemical film, while nanodiamond generates a carbon-rich lubricating film through the rolling bearing effect and the transformation of sp3 to sp2 carbon structures. The synergistic effect of both drives the dynamic gradient evolution of the tribofilm from "tribochemical film-dominated" to "carbon-based lubricating film-dominated," achieving long-lasting lubrication. Molecular dynamics simulations further clarify that low-concentration ionic liquid promotes the rolling friction of nanodiamond by improving its dispersion, while high-concentration ionic liquid inhibits the effective interaction between nanodiamond and the substrate due to excessive adsorption. This study highlights the role of concentration regulation in interfacial adsorption and synergy in multi-component lubrication systems, offering theoretical support for high-performance nanolubricants.

The application of ultrasonic longitudinal-torsional (LT) machining in the field of machining brittle and hard materials such as ceramics and titanium alloys has been increasingly emphasized. Aiming at the existing ultrasonic LT shank, mainly using piezoelectric materials resulting in low power density, overheating failure, and small torsional vibration components, a new ultrasonic LT shank based on giant magnetostrictive materials is designed. The conical transition hollow horn and giant magnetostrictive ultrasonic LT transducer are designed by theoretical analysis method, and the effects of different spiral groove parameters on the resonant frequency and torsion-longitudinal ratio of the horn are analyzed by using finite element software, and the modal analysis is carried out for the shank. Finally, the ultrasonic LT shank is subjected to experimental studies on impedance characteristics, frequency amplitude response, and voltage amplitude response, and the simulation and experimental results show that the designed shank has a resonant frequency of 19.12kHz, a maximum longitudinal amplitude of 14.5μm, a maximum torsional amplitude of 6.1μm, and a maximum torsion-to-longitudinal ratio of 0.46, which is suitable for most of ultrasonic machining, and verifies the correctness of the design methodology.

Ionic liquids (ILs), as novel electric-controlled lubricants, can regulate their tribological behavior under electrified sliding. This study systematically investigates the tribological properties and interface adsorption dynamics of ILs with different chain lengths under electric field control, combining macroscopic experiments and molecular dynamics simulations. Compared to the base lubricant, longer-chain ILs form more stable tribofilms at the electrified interface, reducing the friction coefficient and wear volume by 33.13 % and 79.61 %, respectively. The-COO-group plays a dominant role in tribofilm formation and alters the dynamic migration of ILs. The applied electric field weakens the hydrogen bonding between ILs and the base lubricant, promotes ILs accumulation at the electrified interface, and effectively reduces shear stress.

This work explores the lubrication properties of aqueous solutions containing ionic liquids in contact with cemented carbide and titanium alloy, focusing on the influence of alkyl chain structure. Surface morphology and chemical elements of the worn surface were analyzed using SEM and XPS, and the corrosion resistance was tested. The findings indicate that lubricants containing ionic liquids with unsaturated long alkyl chains can achieve a 70% reduction in friction coefficient and a 91% decrease in wear volume. Ionic liquids in aqueous solutions can effectively prevent the corrosion of gray cast iron by water molecules. Also, quantum chemical calculations and molecular dynamics simulations suggest that anions with unsaturated long alkyl chains exhibit a low energy gap and strong adsorption to the titanium alloy substrate. This implies that to react thermochemically with the metal substrate when it is heated by friction, creating a protective tribofilm. In the torque tests, lubricants containing ionic liquids with unsaturated long alkyl chains penetrate the gaps between the tap and titanium alloy more easily, adsorb onto the contact interface, and form a protective film, resulting in lower torque values. This suggests that the lubricant can serve as a high-performance potential additive in metalworking fluids.

The gecko can achieve flexible climbing on various vertical walls and even ceilings, which is closely related to its unique foot adhesion system. In the past two decades, the mechanism of the gecko adhesion system has been studied in-depth, and a verity of gecko-inspired adhesives have been proposed. In addition to its strong adhesion, its easy detachment is also the key to achieving efficient climbing locomotion for geckos. A similar controllable adhesion characteristic is also key to the research into artificial gecko-inspired adhesives. In this paper, the structures, fabrication methods, and applications of gecko-inspired controllable adhesives are summarized for future reference in adhesive development. Firstly, the controllable adhesion mechanism of geckos is introduced. Then, the control mechanism, adhesion performance, and preparation methods of gecko-inspired controllable adhesives are described. Subsequently, various successful applications of gecko-inspired controllable adhesives are presented. Finally, future challenges and opportunities to develop gecko-inspired controllable adhesive are presented.

In contact models, traditional profile description methods are based on all sampling points of the profile. The methods can only describe the features in the height direction of profile, but are difficult to describe the profile features perpendicular to the height direction, which is the main obstacle to side contact modeling. In this paper, a profile description method based on peaks is proposed, which enables the profile features perpendicular to the height direction of the profile to be expressed. The statistical distribution law of the horizontal distances perpendicular to the height direction of the profile between adjacent asperities on anisotropic contact surfaces is investigated for the first time, and it is found that the distribution of the horizontal distances is very close to the normal distribution, but the values are different in different texture directions. The distribution law of the height differences between adjacent asperities is also investigated and is found to be close to a normal distribution, but the numerical values are different from the normal distribution of profile heights. Based on the results, the distribution function of the contact angle widely used in side contact model is replaced, and a new side contact model is proposed. By the model, the effects of the statistical parameters of surface profile and the material parameters of surfaces on the surface contact characteristics are investigated. The results of investigation show that the effect of the standard deviations of the horizontal distances between asperities in different texture directions on the normal contact stiffness between surfaces is obvious, and the normal contact stiffness will decrease with the increase of the standard deviation of the horizontal distances in any direction.

As a new remanufacturing technology, laser cladding can repair damaged parts in large valves in nuclear power plants. The objective is to enhance the surface morphology quality of parts post-remodeling, the paper optimizes the key process parameters in the laser cladding process. Numerical simulation was used to analyze the influence of each process parameter ( laser power, scanning speed, powder feeding speed) on the morphology of the cladding layer. The laser power and powder feeding rate were positively correlated with the width of the cladding layer, and the scanning speed was negatively correlated with the width of the cladding layer. The orthogonal experiments are designed based on the Taguchi method, and the Stellite6 single cobalt-based alloy cladding layer was prepared on the WCB low-carbon steel substrate. Analysis of variance and RSM was used to analyze the experimental results. The influence order of process parameters on the morphology of the cladding layer was determined. The regression prediction model was established to analyze the relationship between the process parameters and the morphology quality (width and height) of the cladding layer. The errors of the model are 5% and 3.5%, respectively. The optimal combination of process parameters is determined as follows: P = 1700 W, Vs = 8 mm/s, Vf = 26 g/min. The cladding layer prepared by the optimal process parameters has fine structure and good bonding. The accuracy of the predictions was validated using this model, which offered valuable theoretical guidance for predicting and controlling the geometric characteristics of the laser cladding of Stellite6 alloy.

Hard and brittle alloy materials are of great importance in critical fields such as aerospace, military, and semiconductors. To address the challenges encountered in machining hard and brittle materials, a proposed solution is a dual-excitation ultrasonic elliptical vibration-assisted cutting system with adjustable amplitude. The vibration system undergoes modal simulation using finite element software to examine the effects of the length of the amplitude-variable rod and the flange position on the intrinsic frequency of the ultrasonic transducer. Additionally, harmonic response analysis is conducted to validate the design of the transducer. The impedance characteristics of the ultrasonic elliptical vibration device are analyzed, and experimental tests are performed to measure the amplitude. The results demonstrate that the resonant frequency of the ultrasonic vibration system is 19 kHz, with a maximum amplitude of 4.3 µm along the X-axis and 5.7 µm along the Z-axis, enabling the formation of an elliptical vibration trajectory.

In this work, four types of protic ionic liquids were prepared for use as pure water additives to investigate the effect of anionic alkyl chains on the tribological and drilling performance of a titanium alloy. Copper block immersion tests and electrochemical tests were conducted to compare their corrosion resistance. The results indicate that the ionic liquid containing OH and CC in the anionic alkyl chain led to stronger adsorption onto the metal substrate, providing excellent tribological performance and the highest corrosion inhibition rate (η = 98.45 %). According to density functional theory, wear scar surface analysis, and molecular dynamics simulation, the low energy gap of the anion (ΔE = 0.033 Ha) indicated that it exhibited higher reactivity. Thus, it was more susceptible to frictional chemical reactions with the metal substrate under the action of frictional heat during shearing, ultimately forming a friction film with a thickness of 20-97 nm. The ionic liquid demonstrated good wetting properties in a drilling test, enabling its effective penetration into the gaps between the drill bit and the workpiece to achieve lubrication and cooling effects. Thus, the axial force and drilling temperature were significantly reduced. Additionally, biotoxicity tests indicated that the ionic liquid is an environmentally friendly substance.

Microphone array-based beamforming algorithms are widely used in sound source identification, fault diagnosis, and radar communication because of their excellent performance. However, their limited spatial resolution and high dynamic side flap level seriously affect the recognition accuracy. To explore a high-performance beamforming sound source identification algorithm, the microphone array compressed beamforming underdetermined equation is solved by extending the iterative threshold. A sound source identification model is established, and a new compressed beamforming (CSB-II) algorithm is proposed. Numerical simulations show that the CSB-II algorithm can effectively reduce the starting frequency of sound source identification and has high sound source identification accuracy. The effects of signal-to-noise ratio, sound source distance, and array number on sound source identification accuracy are analyzed separately. The laws affecting sound source identification accuracy are derived from guiding actual sound source measurements.

The magnetization and magnetostrictive strain of giant magnetostrictive materials exhibit a complex nonlinear trend under the coupling of multiple fields, including magnetic field, temperature field, and prestress field. To enhance prediction accuracy, we propose a three-dimensional magnetic-thermal-force coupled nonlinear multi-scale hysteresis vector model. This model is derived from the principles of thermodynamics and continuum mechanics, taking into account the interactions among magnetic domains, grains, polycrystals, and macroscopic scales. It combines the volume-averaging principle of magnetic domain microscopy with the generalized Jiles-Atherton hysteresis model. The predicted hysteresis magnetization and magnetostrictive strain curves obtained from this model are in good agreement with experimental results. By analyzing the predicted hysteresis magnetization and magnetostrictive strain under different conditions, we demonstrate that our proposed model can comprehensively describe the effects of temperature and prestress on the multi-field coupled hysteresis behaviors of giant magnetostrictive materials. Moreover, it provides theoretical guidance for both macroscopic and microscopic optimization in designing active devices incorporating super magnetostrictive materials.

In this work, an ionic liquid (G-RIC) with excellent lubricating performance was successfully prepared, and the tribological properties as an additive in glycerol-water solutions were explored. The results indicated that 2.0 % additive content can reduced the friction coefficient to below 0.1, leading to a decline in the wear volume of 76 %. Gray cast iron corrosion tests revealed that the additive exhibited excellent corrosion resistance. Quantum chemical calculations revealed that the anion RIC has a low energy gap (Delta E = 0.034 Ha), which implies that it is more prone to undergoing tribochemical reactions with the metal substrate under frictional heat. The synergistic action of the liquid lubrication layer, adsorption film, and friction protective film created an interface that easily shears.

In this study, water-soluble additives with excellent performance were designed, and their anticorrosive, tribological characteristics, and antibacterial properties were evaluated. Combined with molecular dynamics (MD), the interfacial behavior of additives on metal surfaces was investigated at the atomic scale. The results showed that the additive molecules could reduce the wear rate of ethylene glycol aqueous (EGaq) by 94.7 %, exhibiting excellent anticorrosive efficiency while also possessing certain antibacterial properties. MD results indicated that the additive could firmly adhere to the metal surface due to its higher electron transfer rate, and the interfacial interaction energy increased with the extension of the carbon chain. The coexistence of longer alkyl chains and frictionally active elements ensured the overall stability of the adsorption film.