Friction stir welding (FSW) joins two metals in a solid state, requiring moderate heat input and tool pressure. Steel is heavier than aluminium, but because of its low cost and high strength, aluminium can’t entirely replace steel. Unlike fusion welding, FSW is a viable technique for joining aluminium and steel, since it reduces solidification-related defects and produces thin intermetallic compounds (IMCs) and low residual stress. There is a lack of research on the optimisation of FSW parameters for joining aluminium and steel sheets, as well as a comparative discussion on the effects of multipass and filler material on friction stir-welded joints of aluminium and steel. This literature aims to compile research articles for comparative discussion on welding parameters optimisation, filler material, and multipass for friction stir welding of aluminium and steel. The influences of welding parameters and current strategies, such as hybrid FSW and ultrasonic vibration FSW, have been discussed. Key findings from the literature suggest that, under ideal conditions, the mean IMC thickness was found to be 4 to 5 µm, and the mean ultimate tensile strength was 85% of that of the Al-base metal for the butt joint configuration. The IMC thickness for the lap joint configuration was less than 1.2 µm at a pin plunge depth of 0.2 mm and at a pitch of 0.4 to 1.2 (mm/rev). After applying proper filler material with suitable plunge depth, no IMC of the base material was found, hook flaws were minimised, and better tensile strength was attained. Joining of sheets less than 3 mm with filler material is better than a second pass for the butt joint. Filler material, which is a solid soluble in aluminium, produces a stronger weld compared to that which is a solid soluble in iron.

Abstract Laser directed energy deposition (LDED) is widely used in manufacturing but defects such as lack of fusion, porosity, and inhomogeneous microstructures are reducing the mechanical strength. To solve these issues, ultrasonic vibration-assisted (UV-A) LDED has been introduced. Studies show that ultrasonic vibration enhances the strength of the fabricated workpiece by reducing these defects. To control the mechanical properties and defect formation in LDED, it is essential to analyze the material flow inside the fabricated part. Despite many advances, understanding the material trajectories inside the fabricated part is still insufficient. This research aimed to investigate the material movement along the vertical and across the horizontal deposition direction. Experiments were designed utilizing an ultrasonic vibrator to examine the effects of ultrasonic vibration on material movement. Fe–Cr stainless steel powder was used for fabrication with an alternative powder (pure cobalt, Co) to trace the elemental movement during the process. The result demonstrated that utilizing ultrasonic vibration resulted in a homogenous distribution of Co in the vertical direction, exhibiting around 40% more concentration in the molten pool and around 54% higher in the upper layer. UV-A LDED affected Co distribution across adjacent tracks rising from around 1.1% at Location 1 to approximately 1.3–1.6% at Locations 2–4, in contrast to the inconsistent presence of 1.1–1.7% observed solely at Locations 2 and 3 without UV-A. Lastly, the influence of material distribution due to ultrasonic vibration on microhardness of the deposited tracks was also tested and it demonstrated positive enhancement in both vertical and horizontal direction.

Abstract This study presents a comparative analysis between conventional friction stir welding (CFSW) and flexible ultrasonic-enhanced friction stir welding (FLEX-USE-FSW) applied to a 3-mm-thick AA6082-T6 aluminum alloy. A novel ultrasonic system integrated into the tool holder was employed to introduce axial ultrasonic vibrations during the welding process. Mechanical testing, microstructural characterization, electron backscatter diffraction (EBSD), process force monitoring, and laser vibrometry were conducted to evaluate the influence of ultrasonic excitation on weld quality and process behavior. The results show that ultrasonic assistance reduces axial and traverse forces by up to 20%, broadens the operational window for tensile strength and elongation, and enhances material plasticization. EBSD analysis revealed a higher fraction of low-angle boundaries and modified grain texture in the ultrasonic-assisted stir zone (SZ), suggesting a change in recrystallization dynamics. Cross-sectional imaging revealed a larger and more homogeneous stirred zone in FLEX-USE-FSW, accompanied by reduced defect formation at elevated welding speeds. Additionally, laser vibrometry measurements showed improved energy transmission in specimens oriented parallel to the rolling direction. The findings demonstrate that ultrasonic excitation has a positive effect on weld morphology, mechanical properties, and microstructural evolution, particularly under high-speed and low-heat input conditions.

ABSTRACT Carbon fiber reinforced polymers (CFRP) are widely used in unmanned aerial vehicles due to their high specific modulus and strength. However, components fabricated by conventional vacuum‑assisted resin transfer molding (VARTM) often exhibit low intrabundle permeability and incomplete interlayer filling. To address these limitations, this study introduces an ultrasonic‑assisted VARTM process. A custom-sdesigned system was first employed to establish a stable parameter baseline for VARTM. Single-factor experiments were then conducted to investigate resin impregnation under ultrasonic vibrations at different frequencies. Results indicate that higher ultrasonic frequencies significantly enhance resin wetting within carbon fiber bundles. Moreover, ultrasonic assistance at 22 kHz effectively reduces the formation of interlayer voids. This work presents a physical approach that improves the VARTM molding process effectively.

ABSTRACT This study proposed an ultrasonic adhesive‐impact bonding process tailored for carbon nanotube (CNT)‐reinforced epoxy adhesive joints. A predictive model for shear strength was established using the response surface methodology (RSM), and the optimal process parameters were determined. Under optimal conditions, the fabricated 6061 aluminum alloy/carbon fiber‐reinforced polymer (CFRP) joint exhibited a shear strength of 30.77 MPa, representing a 16.46% improvement over conventional bonding processes. The molecular dynamics (MD) simulation results indicate that ultrasonic vibration not only effectively enhances the filling behavior of adhesive molecular chains but also significantly promotes chemical reactions at the interface and within the adhesive layer. Compared with the model without ultrasonic vibration, the number of KH550 molecules participating in crosslinking increased by 57.14%, and the number of CN bonds formed increased by 63.64% under ultrasonic vibration. Meanwhile, the number of amino groups on the CNT participating in crosslinking and the associated CN bonds formed increased by 60% and 33.33%, respectively. The experimental results on interfacial microscopic morphology and chemical composition were consistent with the findings from MD simulations.

ABSTRACT This study examines the synergistic effects of plasma-assisted heating and ultrasonic vibration on the hard turning of 34CrNiMo6 steel, aiming to minimize tool flank wear. While cubic boron nitride (CBN) and tungsten carbide tools were evaluated, CBN demonstrated superior wear resistance, with statistical analysis confirming that the tool material was the most significant factor influencing wear. A hybrid machining approach was developed, integrating a plasma system for localized workpiece softening and ultrasonic vibration to reduce cutting forces through intermittent tool-workpiece contact. Using Taguchi-designed experiments, the optimal parameters for minimal flank wear were identified: CBN tools operating at reduced cutting conditions (0.50 mm depth of cut, 0.08 mm/rev feed, 40 m/min speed) combined with controlled plasma current (25 A) and maximum vibration amplitude (10 µm). Results revealed a dual-phase plasma current effect, initial force reduction followed by thermal wear at excessive current, and demonstrated that vibration amplitude significantly lowers wear.

Frontal beak reduction is a critical and challenging step in endoscopic sinus surgery (ESS) for chronic rhinosinusitis (CRS). Traditional high-speed drills can risk thermal injury and soft tissue trauma, whereas piezoelectric surgery uses ultrasonic vibrations for selective bone cutting and may improve surgical precision. This study compared piezoelectric devices with conventional drills for frontal beaks reduction. A double-blind exploratory study with randomisation was conducted during the years 2019-2022. Adult CRS patients (n = 43) with prominent nasofrontal beak undergoing ESS were randomised to piezoelectric knife (n = 22) or high-speed drill (n = 21). Exclusion criteria included prior sinus surgery, septoplasty, neoplasms or systemic contraindications. Outcomes included Lund-Kennedy, Lund-Mackay, Sino-Nasal Outcomes Test (SNOT-22), Visual Analogue Scale (VAS) scores and frontal sinus ostium dilatation, measured pre-operatively and at 1, 4 and 24 weeks post-operatively. Both groups showed significant post-operative improvements in Lund-Mackay and SNOT-22 scores (p < 0.05). At 1 week, the piezo group had significantly lower Lund-Kennedy scores (p = 0.022), suggesting better mucosal healing. Correlations in the piezo group were observed between ostium dilatation and improved Lund-Mackay (R = -0.527; p = 0.008) and SNOT-22 (R = -0.405; p = 0.049) at 24 weeks. No significant differences were found in ostium width gain, VAS scores or complications. With piezo devices, the median time of surgery was increased. Piezoelectric surgery is a safe, effective alternative to drills for frontal beak reduction in ESS, with potential benefits for early mucosal healing. Further studies are warranted to confirm long-term advantages.

Microstructure and mechanical property of in situ TiC reinforced Ni-based composite coatings fabricated by ultrasonic vibration assisted laser cladding

Study on microstructure and mechanical properties of laser cladding CBN grinding blocks assisted by various ultrasonic vibration powers

A novel exploration of low damage elliptical ultrasonic vibration assisted cutting method for high-power fiber laser beam shapers

The composite effect of high-speed ultrasonic vibration milling and pickling post-treatment on Ti-6Al-4V fatigue performance

Effect of ultrasonic vibration amplitude on the microstructure, residual stress, and tensile properties of HR-2 austenitic stainless steel

The paper presents an ultrasonic vibration method for laboratory testing of the resistance of materials to the effect of cavitation. The description of the test method and device, the test procedure, and the interpretation of test results are given in accordance with ASTM G32 standard. A comparative overview of the test results of different types of materials is presented: metal (steel, aluminium alloys); ceramics (based on pure and mixed refractory fillers); composite materials with a polymer base; refractory castings and protective coatings. Based on the test results, the correlation of structural characteristics, mechanical properties of materials are determined as a basis for quick selection of materials in hydrodynamic conditions of application.

The widespread and uncontrolled use of antibiotics poses significant dangers and challenges in water treatment and public health. A three-component nanocomposite, Nb2CTx@UiO-66-Bi2Fe4O9, was rationally assembled via a straightforward hydrothermal mixing approach to combine photocatalytic and piezoelectric effects for the efficient decomposition of the antibacterial sulfamethoxazole (SMX). The morphological, chemical, and surface properties of the materials were tested by electron microscopic tools, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman microspectroscopy, Fourier transform infrared spectroscopy (FTIR), and energy dispersive X-ray spectroscopy (EDS), which confirmed the tight interfacial bonding between the three components, while electrochemical impedance spectroscopy (EIS), photoluminescence (PL), and Mott-Schottky assessments revealed enhanced charge transfer transitions. The elevated performance originates from the coactive piezoelectric photocatalysis in which piezoelectric Bi2Fe4O9 generates a polarization field under the action of ultrasound to promote charge separation, Nb2CTx acts as a conductive and stable mediator, and UiO-66 enhances pollutant adsorption and interfacial charge transport. In addition, Nb2CTx@UiO-66-Bi2Fe4O9 still possesses high photocatalytic performance at various pH values, pollutant concentrations, and water sources. In combination with ultrasonic vibration and visible light irradiation, Nb2CTx@UiO-66-Bi2Fe4O9 achieved 91.1% SMX degradation within 160 min and 98.2% within 30 min under the combination of UV light and ultrasonic quivering. The catalyst retained approximately 89.4% of its original activity after five consecutive cycles, demonstrating excellent durability. Therefore, this study demonstrates that the as-prepared Nb2CTx@UiO-66-Bi2Fe4O9 catalyst holds great potential for environmental remediation.

Establishment of strain rate prediction model for ultrasonic elliptical vibration cutting of 92W-5Ni-3Fe

Purpose. The aim was to develop a method that would enhance the efficiency of classifying crushed ore by particle size, thereby preparing it for metallurgical proces Methodology. The following methods were used in the work: analysis of scientific and practical solutions; statistical methods for processing the results of experimental studies; methods of analytical synthesis; and methods of computer modeling for the synthesis and analysis of mathematical models. Findings. The forces acting on crushed ore particles as they move in a layer of material on a vibrating screen have been investigated. The mechanism of contact interaction between solid-phase pulp particles has been substantiated, taking into account the geometry of contact surfaces, mechanical properties of materials, and loads applied to the contact. It has been proven that crushed ore particles and gas bubbles in the pulp flow, due to their individual characteristics (size, density, mass), each react in their own way to acoustic energy and the dynamic influence of ultrasonic vibrations applied and propagated in the medium. Based on the results of the analysis, it was concluded that ultrasound contributes to the diversity of dynamic reactions and increases the mobility of the components of the heterophasic structure of pulp materials. The conditions under which the influence of ultrasonic vibrations in ore pulp containing gas bubbles causes the destruction of ore aggregates and flocculates in it were analyzed. The parameters of ultrasonic vibrations that cause cavitation, the collapse of gas bubbles, and pressure surges of destructive amplitude in the pulp have been determined. It has been proven that acoustic emission arising from the propagation of ultrasonic vibrations in the pulp can be a general characteristic and property that determines the requirements for the form and parameters of controlling this process. A method for improving the efficiency of fine wet ore screening using the dynamic force of ultrasound on the classification product has been proposed. Originality. A method has been developed to increase macrodiffusion and reduce the overall resistance to the movement of crushed ore pulp particles during screening by introducing ultrasonic vibrations of a certain amplitude and frequency into the oversize product of the screen, which allows increasing the speed of passage of crushed ore particles through the screen and reducing the proportion of unclassified product. Practical value. The analysis of the results obtained shows an increase in the efficiency of fine wet screening of crushed ore by an average of 3 % due to ultrasonic treatment of the input product of the screen.

Mechanism and experimental study on longitudinal-torsional ultrasonic vibration drilling of ceramic matrix composites

To enhance the operational damage resistance of hydraulic machinery, this study employed laser cladding technology to fabricate a Co37.4Cr30Ni20Al5Ti5Nb2.6 high-entropy alloy coating on 04Cr13Ni5Mo substrate. The influence of laser power on the microstructure and properties of the coating was systematically investigated. Based on preliminary research, the friction-wear performance and cavitation erosion behavior of the coatings prepared at 3000 W, 3200 W, and 3400 W were specifically examined. Results indicate that as the laser power increased from 3000 W to 3400 W, the microhardness of the coating gradually decreased from 345.3 HV0.2. At 3000 W, the precipitation of trace strengthening phases significantly enhanced the mechanical properties. In wear tests under a 20 N load for 30 min, the wear rate of the coating prepared at 3000 W was 1.41 × 10-4 mm3/(N·m), which is 13.5% lower than that of the 3200 W coating (1.63 × 10-4 mm3/(N·m)) and 16.07% higher in wear resistance compared to the substrate. Cavitation erosion tests revealed that after 20 h of ultrasonic vibration, the mass loss of the 3000 W coating was only 2.35 mg, representing an 88.89% reduction compared to the substrate (21.15 mg), and significantly lower than that of the 3200 W (4.57 mg) and 3400 W (3.85 mg) coatings. This study demonstrates that precise control of laser power can effectively optimize the cavitation erosion resistance of high-entropy alloy coatings, providing technical support for their application in harsh environments.

Piezocatalysis can convert mechanical energy to chemical energy. Thus, it has shown great potential in energy and environmental applications. As a widely studied piezocatalyst, barium titanate (BTO) can catalyze water splitting and pollutant degradation under ultrasonic vibration. However, mechanistic insight into the role of surface termination, symmetry, and layer thickness in piezocatalysis has been largely underexplored. In this work, using BTO as an example, we adopted the quantum-continuum-electrochemical (QCE) method to systematically study how these factors determine piezocatalytic activity. Our simulation reveals that TiO2-terminated BTO shows a more suitable redox potential window than BaO-terminated BTO in piezocatalysis. Moreover, we also find that symmetric BTO with mild thickness possesses a well-matched redox potential to the experimental voltage window of water splitting, while asymmetric BTO needs an extremely large thickness to reach the same performance. Combining our simulation results with experimental literature, we suggest that symmetric TiO2-terminated BTO should be the dominant active moiety in the piezocatalysis of BTO nanoparticles. Our study unravels how the structure of BTO determines piezocatalytic activity, which could benefit further development of piezocatalysts in BTO or other perovskite families.

Study on surface quality in longitudinal-torsional composite ultrasonic vibration assisted drilling of CFRP/Ti stacks