Transparent underwater superoleophobic coatings hold great promise for underwater optics and marine devices, but their practical application is hindered by the inherent conflict between optical transparency, mechanical robustness, and oil-repellent durability. Here, we report a high-performance transparent underwater superoleophobic (TUS) coating designed by covalently anchoring high-molecular-weight poly(acrylic acid) chains onto a robust, porous nano-silica scaffold. The highly hygroscopic PAA chains form a stable hydration layer on the nanostructured surface, which is critical for achieving underwater oil repellency. This rational design combines mechanical stability with a stable hydration layer, enabling the coating to exhibit high transparency (92.3% in water at 550 nm), robust underwater superoleophobicity (oil contact angle: 169° ± 2°; sliding angle: 1.5° ± 0.3°), and near-zero oil adhesion (adhesion force ≈ 0.48 µN). Crucially, the TUS coating demonstrates good durability under the tested conditions, maintaining its anti-oil-fouling performance and optical clarity after prolonged exposure to high-salinity environments (20 days in 3.5 wt% NaCl), elevated temperatures (up to 70 °C), hydrodynamic shear (0.5 m s-1 for 12 hours), and mechanical abrasion. This work provides a feasible strategy for designing multi-functional coatings for demanding applications in underwater optical and marine equipment.

Ultrasonic additive manufacturing (UAM) was employed to fabricate Ti/Al laminated composites and elucidate the relationship between interfacial microstructure and macroscopic tensile behavior. The UAM process produced thermally asymmetric interfaces, where the Ti/Al interface experienced higher local temperatures and more intense plastic deformation, promoting partial dynamic recrystallization and Al grain refinement. In contrast, the Al/Ti interface underwent limited recovery and retained a softer structure. Digital image correlation (DIC) mapping revealed pronounced strain partitioning, with shear localization concentrated near the recrystallized Ti/Al interface. Subsequent short-time annealing induced grain coarsening, dislocation recovery, and stress relaxation at both interfaces, reducing hardness mismatch and improving strain compatibility. The heat-treated laminates exhibited smoother strain fields, more uniform deformation, and a simultaneous enhancement in strength and ductility. Correlative EBSD, TEM, and DIC analyses established a clear mechanistic link between interfacial microstructural evolution and macroscopic deformation response. The findings demonstrate that achieving an optimal strength-ductility synergy in UAM Ti/Al laminates relies primarily on regulating interfacial recrystallization and residual stress rather than merely strengthening the metallurgical bond.

Premature interfacial failure limits the mechanical integrity of Ti/Al laminates fabricated by ultrasonic additive manufacturing. To clarify its crystallographic origin, in situ scanning electron microscopy and electron backscatter diffraction were used to track deformation and damage evolution. The Al layer accommodates most plastic strain through lattice rotation, subgrain fragmentation, and recovery, whereas the Ti layer shows limited rotation and stronger interfacial constraint. Slip transfer analysis based on the Luster Morris parameter reveals that the fraction of highly compatible interfacial segments with m ' >= 0.77 decreases to similar to 15% at high strain. Accordingly, the Ti-side of the interface develops elevated lattice curvature and geometrically necessary dislocation (GND) density, indicating compatibility induced lattice bending and constrained deformation within the Ti boundary layer rather than conventional dislocation pile up in the softer Al. The resulting GND associated hardening increment exceeds 300 MPa locally in Ti but remains below similar to 70 MPa in Al. Interfacial microcracks initiate at similar to 20% strain, evolve into delamination by similar to 30%, and are followed by Al necking and final failure at similar to 40%. These findings show that interfacial weakness and crystallographic incompatibility jointly govern fracture by amplifying local strain gradients and Ti-side hardening near the interface.

A dual-horn ultrasonic shot peening (USP) process was investigated for GH4169 fir-tree slots under confined treatment conditions. Discrete element method (DEM) simulations guided amplitude and filling-rate selection within a fixed apparatus. Among the tested conditions, 140 μm amplitude, 0.4% filling rate, and 90 s treatment produced an ∼18 μm gradient-deformed layer with dense slip bands, elevated local misorientation, increased low-angle grain boundaries, and greater compressive residual stress. The mean high-temperature fatigue life increased by 136% relative to the untreated specimen, demonstrating the potential of DEM-guided dual-horn USP to improve fatigue resistance under fir-tree-slot confinement.

Previous studies have shown that, at conventional power levels, ultrasonication can also produce graphene quantum dots (GQDs) via a top-down route, but it is more often used as an auxiliary step for dispersing or mildly exfoliating carbon materials, typically together with chemical oxidation or hydrothermal treatments rather than as the main synthesis method. Here, we use high-power ultrasonication and static pressure to strengthen cavitation, so that ultrasound itself becomes a direct and scalable strategy for GQD fabrication. In a pressurized circulation setup, we first track the evolution of graphite at 1500 W and observe a gradual transition from exfoliated sheets to fragmented pieces and finally nanoscale fragments (similar to 0.1 mu m). At the same power, tuning the static pressure from 0 to 6 bar shows that the fraction of small fragments peaks around 2 bar, under which simple filtration and concentration are sufficient to obtain GQDs. Keeping this optimized pressure (2 bar) and increasing the power from 1500 to 3000 and 6000 W further boosts GQD production, accompanied by higher oxidation and larger dot size, as indicated by an increase in Raman I-D/I-G (0.33 -> 0.46), expansion of lattice spacing (0.208 -> 0.243 nm), and higher oxygen content in XPS. Consistently, the photoluminescence evolves into a pattern with coexisting excitation-independent and excitation-dependent regions, and the main emission at lambda(ex) = 420 nm shifts slightly from similar to 470 to similar to 485 nm. Extending the same ultrasonic protocol to graphene oxide precursors yields GOQDs that show strong fluorescence under 365 nm UV without further concentration, suggesting a higher effective yield, while thermal reduction of GOQDs produces Re-GOQDs with larger sp2 domains and GQDlike PL features, helping to clarify how ultrasonic power and precursor type jointly regulate the structure-optical response of GQDs/GOQDs.

To enhance the performance of W360 steel stirring head in friction stir welding (FSW) of 6061 aluminum alloy, an TiAlN coating was applied using physical vapor deposition (PVD) technology. The impact of the coating on tool wear and joint quality was systematically examined. A comparative analysis of wear morphology, microstructure, mechanical properties, element diffusion, and coating failure mechanisms between coated and uncoated stirrers during welding elucidated the strengthening effect of the TiAlN coating through scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) analyses. The findings demonstrate a significant enhancement in wear resistance of the stirring head due to the TiAlN coating. Following welding for 800 mm (cumulative welding length of test plates), the joint welded with the TiAlN-coated stirring head exhibited a tensile strength of 222 MPa (73.8% of the base metal strength, base metal tensile strength: 298 MPa). Microscopic analysis revealed that the TiAlN coating effectively mitigates oxidation of the W360 steel matrix and Al-Fe interdiffusion by impeding the high-temperature adhesion of the aluminum alloy and the abrasive action of hard alumina particles, thereby altering the wear mechanism from “abrasive wear dominated + local dynamic readhesion” to “coating progressive spalling.” This investigation offers theoretical insights and a technical roadmap for the advancement of cost-effective FSW tools for aluminum alloys.

Non-magnetic steels are essential for applications requiring both high mechanical strength and strict magnetic neutrality, such as superconducting systems and nuclear engineering. However, conventional strengthening methods often deteriorate magnetic stability, leading to a persistent trade-off between strength and magnetism. Here, we show that ultrasonic impact treatment (UIT) effectively overcomes this limitation by inducing a gradient dislocation structure that enhances mechanical properties while triggering a near-complete body-centered cubic (BCC) to face-centered cubic (FCC) reverse martensitic transformation in medium-Mn steel, forming a fully austenitic surface layer that suppresses ferromagnetism. Micropillar compression tests show simultaneous increases of similar to 138% in strength and similar to 96% in plasticity compared with the untreated counterparts, attributed to the gradient dislocation structure. The gradient layer also exhibits nearly doubled wear resistance relative to commercial non-magnetic steels. Atomic-scale analysis further reveals a shear-mediated BCC-to-FCC reverse transformation pathway that challenges the classical Bogers-Burgers model, where the BCC lattice first distorts into an intermediate structure and then evolves into FCC through sequential shear. These findings establish UIT as a promising route to design non-magnetic steels with enhanced mechanical performance and magnetic stability. (c) 2026 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )

This article explores the tribological behaviors of Zr 46.5 Cu 45 Al 7 Ti 1.5 bulk metallic glass (BMG) during linear reciprocating sliding against WC ball under different loads. The time-dependent coefficient of friction indicates the presence of a significant “Running-in” stage during wear tests, with the duration of this stage extending as the normal load increases. The structural characteristics of the samples are examined using X-ray diffraction, which confirmed their noncrystalline nature. The wear surfaces and debris of the BMG and WC ball are analyzed using scanning electron microscopy coupled with energy-dispersive spectroscopy. The results demonstrate that the predominant wear mechanisms at low loads are abrasive and adhesive wear, accompanied by minimal oxidative wear. Under high loads, adhesive and oxidative wear dominate. A high wear rate is associated with adhesive wear, whereas a low wear rate is linked to oxidative wear.

Enhancing the surface quality and productivity of multi-needle ultrasonic peen forming (UPF) requires automation and precise process optimization. However, accurately predicting UPF responses remains challenging due to complex nonlinear interactions among process parameters, which are often oversimplified in existing models. To address this, a novel robotic multi-needle UPF system is developed, integrating response surface modeling to enhance predictive accuracy, optimize process parameters, and validate performance on AA2024-T3 metallic workpieces. A systematic experimental study is conducted using response surface methodology (RSM) with an I-optimal design, where quadratic regression (QR) models correlate manipulated variables (MVs) such as vibration amplitude, air pressure, and peening passes with key process variables (PVs), including arc height, surface roughness, hardness, and peen forming energy. Additionally, Gaussian process regression (GPR) and artificial neural networks (ANN) models are built for enhanced predictive accuracy. Results demonstrate that all models achieve high accuracy, with R2 values exceeding 0.91 across all PVs. The convex nature of QR models facilitates global optimization using a multi-objective desirability function, enabling efficient parameter tuning. Optimized process settings reduce surface roughness and peen-forming energy by approximately 43% and 20%, respectively, while increasing hardness by 25%. To validate scalability and industrial applicability, an industrial case study is conducted on larger specimens, maintaining a consistent aspect ratio with Almen-sized strips.

Ultrasonic vibration assisted laser manufacturing (UVA-LM) represents a transformative hybrid approach that synergistically integrates high-frequency ultrasonic vibrations (>20 kHz) with laser-based processes to overcome the inherent limitations of conventional laser manufacturing. This comprehensive review examines recent advancements in UVA-LM, encompassing additive manufacturing (UVA-AM), cladding (UVA-LC), and welding (UVA-LW). We critically analyze the underlying mechanisms, primarily acoustic streaming and cavitation-induced effects, which profoundly enhance molten pool dynamics by promoting grain refinement, homogenizing microstructures, and suppressing defects such as cracks and porosity. Experimental and simulation studies demonstrate that optimized ultrasonic parameters (frequency, amplitude) significantly improve mechanical properties, surface integrity, and dimensional accuracy. These enhancements are manifested as marked grain refinement, reduction of secondary phases, lower surface roughness, and the induction of deeper compressive residual stress layers. The review also addresses critical design methodologies for ultrasonic tooling, substrate resonance tuning, and hybrid system integration. Furthermore, we highlight the pivotal role of UV in regulating particle dynamics and temperature distribution, particularly in directed energy deposition, with recent models achieving prediction accuracies exceeding 97 %. Despite substantial progress, knowledge gaps persist in quantifying ultrasonic parametric effects across emerging manufacturing platforms. UVA-LM emerges as a pivotal technology for high-integrity applications in aerospace, biomedical, and energy sectors. Future research directions should emphasize in-situ monitoring, advanced multi-physics modeling, and scalability for industrial adoption. This review synthesizes critical insights to establish a structured evaluation framework, documenting research priorities and key findings across the literature.

Improving aluminum alloy's microstructure and mechanical performance necessitates a refined surface treatment process. Hence, this study examines the mechanical characteristics of a 6061-T4 aluminum alloy used in an electric vehicle battery enclosure, treated with robotic ultrasonic needle peening (UNP) featuring multiple needles. Results indicate that robotic UNP with multiple needles induces substantial work-hardening layers of 375 mu m and 750 mu m at vibration amplitudes of 21 mu m and 35 mu m, respectively, enhancing surface microhardness by 33.6 % and 54.3 % at corresponding amplitudes. Furthermore, the yield strength values of the treated samples are 166 +/- 2.7 MPa and 176 +/- 1.5 MPa at vibration amplitudes of 21 mu m and 35 mu m, respectively, representing improvements of 9.93 % and 16.56 % compared to the untreated sample (151 +/- 3.4 MPa). These findings provide crucial insights into aluminum alloy mechanical behavior and advance automated peening across industries.

The present study effectively produced a high-entropy alloy (HEA) coating of AlCrFeMnNi on AISI 304L steel using resonant ultrasonic vibration-assisted laser cladding (R-UVALC). An investigation was conducted to examine the impact of dilution rate on the phase composition, microstructure, and mechanical and tribological properties of AlCrFeMnNi coatings. The coating, which was created utilizing the appropriate dilution rate, was thoroughly characterized using EDS mapping and TEM investigation. The results suggest that a higher dilution rate causes a change in the AlCrFeMnNi coating, transforming it from a single solid solution phase (BCC) into a two-phase solid solution containing both FCC and BCC phases. The analysis conducted using transmission electron microscopy (TEM) reveals that the AlCrFeMnNi coating, when diluted at an optimal rate of around 37%, is predominantly composed of a disordered body-centered cubic (BCC) phase and an ordered BCC (B2) phase featuring a spinodal decomposition structure. The AlCrFeMnNi coating has an average microhardness of approximately 540 HV, which is over 2.5 times higher than the microhardness of the substrate. Additionally, it was also established that the dilution rate has an impact on the occurrence of phases, which subsequently affects the mechanical and antifrictional properties of the coating. The integration of ultrasonic vibration in laser cladding enhances quality and improves mechanical and tribological properties, thereby reducing material costs and promoting an environmentally friendly process when compared to conventional cladding.

Electropulsing was employed to assist the ultrasonic consolidation of Cu/Al heterogeneous lamellar structures, which effectively optimizes the microstructure by reducing dislocation density and facilitating recrystallization and recovery, particularly within the Al layer. Due to the relatively high electrical resistivity of aluminum and the skin effect associated with electropulsing, electrical energy was preferentially concentrated near the Al interface, thereby promoting significant grain recrystallization and enhancing the interfacial bonding strength of the Cu/Al structure. (c) 2025 Society of Manufacturing Engineers (SME). Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Industrial oily wastewater and oil spills necessitate efficient oil/water separation materials resilient to harsh environments. Herein, a highly porous composite coating, comprising poly(acrylic acid) (PAA) and microclusters of SiO2-embedded PPy nanospheres (PPy-SiO2 MCs), is fabricated on stainless steel mesh via layer-by-layer (LbL) electrostatic assembly. The coating combines the stable hierarchical nanostructure of PPy-SiO2 MCs with the exceptional hydrophilicity of PAA, conferring superhydrophilicity and durable underwater superoleophobicity (UWOCA >150(degrees)). The resulting coated mesh exhibits outstanding separation efficiency (>99.9 %) and high flux for diverse oil/water mixtures, even under aggressive conditions including extreme pH (1-13), high salinity (10 wt% K2SO4), and high temperature (>80 C-degrees). It also demonstrates excellent cyclic stability (>99.9 % efficiency after 20 cycles) and long-term durability in aggressive saline media (10 wt% K2SO4) (>99.9 % after 6 days). This work provides a feasible, cost-effective strategy for durable, high-performance oil/water separation in harsh environments.

Enhancing the peening uniformity and tribological behavior of aluminum alloy requires a more controllable surface treatment process. Thus, in this work, the tribological behavior of an electric vehicle's battery enclosure, which is made of a 6061-T4 aluminum alloy treated by robotic ultrasonic needle peening (UNP) with multiple needles technology has been investigated at elevated temperatures. The results showed that the robotic UNP treatment with multiple needles produced significant hardened surface layers of 375 mu m and 750 mu m at vibration amplitudes of 21 mu m and 35 mu m, respectively, and increased surface microhardness by 33.6% and 54.3% at respective amplitudes. Compared to untreated samples, robotic UNP treatment significantly improves wear resistance by reducing the wear rate by up to 38% and reducing the friction coefficient by up to 57% when subjected to a wear load of 40 N and a testing temperature of 300 degrees C. These improvements are attributed to the formation of protective layers and enhanced plastic deformation of the 6061-T4 aluminum alloy under elevated temperatures. The results of this study demonstrate a shift in the wear mechanism, transitioning from abrasive wear to oxidative wear, softening, and delamination as the wear load and temperature increase. The findings not only provide valuable insights into the tribological behavior of aluminum alloys at elevated temperatures but also make a significant contribution to the advancements of automated peening in various industries.

Hole structures represent discontinuities in mechanical parts, and their inner walls need to be surface strengthened to enhance the service performance. In this study, a novel ultrasonic shot peening (USP) method, which is equipped with a wave-shaped horn and can be inserted into holes is developed to strengthen the fastener holes. Firstly, the axis uniformity of static and motional USP systems is compared in 304SS holes. After treated by static USP, the peening intensity along the hole axis is consistent with the wavy surface of the horn. The impact velocity and impact number of the balls driven by the trough of the horn are approximately four times and three times higher, respectively, compared to those driven by the peak structure. Thus the regions treated by the trough of the horn exhibit greater surface roughness (Ra = 0.97 mu m), higher hardness (510 HV) and a deeper deformed layer (94.3 mu m). While the motional system effectively improves the axis uniformity of the holes by diminishing the concentration of the stronger and weaker shot peening areas. For GH4169 holes treated by motional USP, a cold work layer with depths of 100-150 mu m is formed; a plastic deformed layer exceeding 50 mu m is observed and a residual compressive stress layer exceeding 200 mu m is introduced. These results are consistent with those of plate or cylindrical samples treaded by USP. Moreover, the differences between USP and other techniques are subsequently discussed.

Ultrasonic shot peening (USP) is a surface enhancement technology that improves the surface properties of workpieces and enhances their fatigue life. This study employs discrete element method (DEM)-based USP simulations to systematically analyze the kinematic behavior of shots impacting the target and to explore their effects on the peening intensity and uniformity of GH4169 hole structures. Three different horn designs (2G-0, 2G-45, 2G-60) were tested. The varying protrusion structures significantly increased the normal impact velocity of the shots, with the 2G-45 horn achieving the maximum impact velocity of approximately 18 m/s. As the number of shots increased, the collision counts and uniformity varied accordingly. At 20 % shot quantity, 2G-45 achieved higher collision counts without significant concentration of impact velocities. The surface of the hole wall treated by stationary shot peening exhibited stripes of varying depths, with the normal velocity and impact frequency in high-intensity areas being 2.25 times and 3 times higher, respectively, than those in low-intensity areas. Introducing axial motion to the USP system reduced differences in impact velocity and frequency across regions, but uniformity remained insufficient. With a combined strategy of 30 % stationary and 70 % dynamic peening, shot normal velocities concentrated within 0-10 m/s, significantly improving uniformity. As for the USP exams, a near-surface plastic deformation layer of 20-50 mu m formed: high-velocity and high-frequency impact zones reached 50 mu m, while low-velocity and low-frequency areas attained 20 mu m. Ultimately, the hybrid strategy homogenized the plastic deformation layer, validating the consistency of simulation results. Furthermore, USP treatment increased the near-surface residual compressive stress depth in M-45 sample to 200 mu m (twice that of AR sample), elevated the peak stress by 32 % to 1034 MPa, and enhanced fatigue life by 71 %.

The design of the resonant ultrasonic vibration-assisted laser cladding (R-UVALC) setup involved employing finite element analysis (FEA) to simulate the ultrasonic transducer, horn, and workpiece in a resonance state. The impact of R-UVALC on AlCrFeMnNi high-entropy alloys was assessed using various ultrasonic vibration amplitudes of 0, 5, 10, and 15 µm, with a constant frequency of 20 kHz. Ultrasonic vibrations reduced pores and cracks and increased the clad breadth, melt pool wetting angle, and laser-clad layer consistency. The columnar elongated grains in proximity to the substrate surface underwent a size reduction and transformed into grains with a more equiaxed shape with the utilization of ultrasonic vibrations at an amplitude of 5 µm. Laser cladding performed without ultrasonic vibrations yields two phases: face-centered cubic (FCC) and body-centered cubic (BCC). However, when the coating is exposed to ultrasonic vibrations with an amplitude of 5 µm, it forms a solitary body-centered cubic (BCC) phase. The microhardness tripled compared to the substrate, and the most significant microhardness value was achieved at 5 µm of ultrasonic vibration. The friction coefficient was assessed at an ambient temperature, revealing that an ultrasonic amplitude yields the lowest friction coefficient, demonstrating the excellent wear resistance properties of the coating. The analysis of the 3D surface profile of the wear indicates that the use of ultrasonic aid with a 5 µm amplitude leads to reduced depth of scars, and the primary wear mechanism observed is abrasive and oxidative wear with fewer grooves and debris. In addition, XPS analysis revealed the presence of metal components in an oxidized condition, suggesting that the wear process is oxidative in nature. Integrating the R-UVALC setup into a resonance state can significantly enhance the efficiency of the laser cladding process in the laser cladding field.