Application Of Ultrasonic Vibration Research Articles

Ultrasonic effect on thickness variations of intermetallic compound layers in friction stir welding of aluminium/magnesium alloys

• The thickness variation of intermetallic compounds (IMCs) along the Al/Mg boning interface were characterized. • Ultrasonic vibration can reduce the thickness of IMCs on the whole Al/Mg boning interface. • The maximum thickness of IMCs locates at about 1 mm below the top surface of welds on transverse cross-section. • The variation trend of average thickness of IMCs on two horizontal cross-sections were compared and analyzed. The formation of intermetallic compounds (IMCs) in friction stir welding of Al and Mg alloys worsens the strength and toughness of dissimilar joints. Understanding of the morphology and thickness variation of IMCs at different locations inside the weld will lay solid foundation for mitigating the unfavorable effects of IMCs. In this study, friction stir welding tests of Al/Mg alloys with and without exertion of ultrasonic vibration were performed, and the distribution of IMCs at transverse and horizontal cross-sections of welds were observed and characterized at more checking points. The results show that as the depth distance from the top surface of weld gets larger, the thickness of IMCs on transverse cross-section increases first and then decreases, and reaches the maximum value at a depth of about 1 mm. On the horizontal plane at upper part of weld, the thickness of IMCs first increases and then decreases as the distance gets farther from the center of the exit hole, and reaches a stable stage outside of the range covered by the shoulder. The application of ultrasonic vibration can reduce the thickness of IMCs in the whole weld, and make the peak value of IMCs thickness appear at a location nearer the exit hole on horizontal planes at both upper and lower parts of weld.

Interfacial reaction and shear strength of ultrasonically-assisted Sn-Ag-Cu solder joint using composite flux

Cu modified carbon nanotubes (Cu-CNTs) doped flux were prepared in this paper, the influence of the composite flux on the evolution of microstructure and shear strength of Sn-3.0Ag-0.5Cu (SAC305) solder joints were investigated, the ultrasonic vibration (USV) was applied for the solder joint during reflowing. Experiments were designed to modify the CNTs with Cu nanoparticles through electroless modification process. Transmission electron microscopy (TEM) was utilized to obtain the graph of modified CNTs. Using X-ray photoelectron spectroscopy (XPS) spectra to prove that the CNTs were successfully modified with Cu nanoparticles. Compared with the solder joint without USV, the application of USV on the solder joint would alter the morphologies of interfacial IMC layer and grains, reduce the IMC thickness and grain size by 16.6 % and 65.6 %, respectively. Reflow process was implemented to evaluate the microstructure evolution and interfacial reaction of SAC305 solder joint with different content of Cu-CNTs doped flux with USV. It was found that the presence of Cu-CNTs could reduce the thickness and grain size of interfacial intermetallic compound (IMC) within solder joint by 3.1 % and 5.25 %, respectively. After addition of the Cu-CNTs in the flux, the thickening of IMC layer and the coarsen of interfacial IMC grain were suppressed, the optimal inhibition effect was gained when the content of Cu-CNTs was 0.1 wt.%. The shear test was conducted for the Cu/SAC305/Cu solder joint with flux containing Cu-CNTs under different soldering condition, the results indicated that as the content of the Cu-CNTs in the flux increased, the shear strength was significantly enhanced by up to 16.8 %. Furthermore, the application of USV could enhance the shear strength by up to 14.2 % as well, The fracture type of solder joints without USV treatment also changed from ductile-brittle mixed type to ductile type as the content of Cu-CNTs in the flux increased. While, the fracture type of all the solder joints with USV treatment was ductile type.

Surface quality and pullout strength of ultrasonically-assisted drilling cortical bone.

Bone surgery is a complex process involving sustainable and healthy human recuperation, but poor surface quality and loose implant fixtures can affect the recovery time of orthopedic patients. However, it has been demonstrated that the application of ultrasonic vibration during drilling procedures can improve the success of bone remediation procedures. The focus of the present paper was on the investigation of surface quality and pullout strength of drilled holes. After analyzing the special kinematic characteristics of the ultrasonically-assisted drilling (UAD), UAD testing using fresh cortical bone was carried out and compared with the results obtained after conventional drilling (CD) procedures. Surface roughness measurements and microscope examination were used to evaluate surface quality, and an electro-mechanical tensile machine was used to measure pullout resistance. The test findings indicated that surface roughness was reduced by 17-68.7% when using UAD; the axial pullout strength of screws inserted into UAD holes was significantly increased by 4.28-30.1% compared to that of CD. It was found also that low spindle speeds and high feed rates reduced surface quality and the stability of the inserted cortical screws. The findings demonstrated that UAD produced better surface quality and higher pullout strengths, which could provide greater stability for implants and improved post-operative recovery.

Effect of ultrasonic vibration on microshear bond strength of flowable composite to enamel

Objective: The present study aimed to assess the influence of vibration effect on microshear bond strength (µSBS) of flowable composite to enamel. Material and Methods: Sixty non-carious extracted human premolar teeth were collected and randomly divided into six groups (n = 10) after being trimmed to produce a smooth flat surface: Flowable composites [Wave (SDI), Wave HV (SDI) and Grandioflow (Voco)] were used as bonding agents without or with vibration using an ultrasonic scaler (Mini Piezon, EMS, Switzerland). Composite resin, with an internal diameter of 0.7mm and height of 1mm, was cured on the substrate. The specimens’ µSBS was tested by a microtensile tester (Bisco, USA) at a crosshead speed of 0.5 mm/min. The bond strength values were analyzed using one-way ANOVA and post hoc Tukey test (p < 0.05). Results: Vibration did not lead to any significant difference in the µSBS values of Wave, Wave HV, and Grandio Flow µSBS values (P=0.690, P=1.000 and P=0.947, respectively). No significant difference was found between flowable composites in terms of micro shear bond strength to enamel (p > 0.05). Conclusions: The application of ultrasonic vibration might not be advantageous in terms of improving the shear bond strength of flowable composites to enamel. KEYWORDS Bond strength; Enamel; Flowable composite; Ultrasonic; Vibration.

The effect of ultrasonic vibration on the springback of incremental sheet forming

In this study, aiming at the springback problem, ultrasonic vibration was applied to incremental sheet forming to assist the sheet forming. The springback distribution of ultrasonic vibration and no ultrasonic vibration was compared. The influence of the application of ultrasonic vibration on the springback of the sheet mental formed was analyzed; and also by adjusting the power of the ultrasonic generator to adjust the amplitude of the ultrasonic vibration, the effect of the ultrasonic amplitude on the springback is studied. Experimental data shows that the effect of ultrasonic vibration on each forming stage is different during the forming process. Therefore, it is necessary to select the best amplitude to assist the sheet forming process to achieve the effect of restraining springback.

Tool wear in laser ultrasonically combined turning of tungsten carbide with PCD tools

Tungsten carbides are typical difficult-to-cut materials due to their high hardness and brittleness, which cause severe tool wear and shorten tool life when being machined during conventional processing methods, leading to a loss of quality and accuracy of the machined parts. In this paper, a novel laser ultrasonically assisted turning technology for tungsten carbides was proposed, and the primary objective of this study was to investigate the behavior of polycrystalline diamond (PCD) tools when turning tungsten carbides with the application of ultrasonic vibration to tools and laser-induced heating to workpieces. To determine suitable parameters, thermal modeling of laser ultrasonically assisted turning of tungsten carbide was employed. Through contrast experiments carried out during conventional turning, ultrasonically elliptical vibration turning, laser-assisted turning, and laser ultrasonically combined turning of tungsten carbides with PCD tools, the tool wear characteristics and dominant wear mechanisms were investigated, and the relation between tool wear and surface quality of workpiece was determined by analyzing the effects of tool wear on the surface roughness values and the microtopography of the machined surface. A significant reduction in the cutting force and a substantial improvement in the tool life were obtained in laser ultrasonically combined turning of tungsten carbides with PCD tools when compared with conventional turning, ultrasonically elliptical vibration turning, and laser-assisted turning; therefore, lower surface roughness values and a good surface quality of the workpiece were obtained. During laser ultrasonically combined turning of tungsten carbides with PCD tools, the wear on the rake face was characterized by micro tipping and chipping, the flank face had shallow micro-grooves oriented along the cutting direction, and the dominant failure mechanisms of the PCD tools were the synergistic interaction of diffusion, oxidation, tipping, and chipping. With the increase in tool wear, the surface roughness values steadily increased in laser ultrasonically combined turning, and the cutting mode was changed from ductile mode turning to brittle mode turning, which resulted in many defects, including pits, voids, grooves, etc., on the machined surfaces.

Experimental and Simulation Investigation on the Ultrasonic-Assisted Bending of Annealed and Aged AA6061 Aluminum Alloy Sheets

This paper aims to investigate the influence of ultrasonic vibration on bending parameters of AA 6061 aluminum alloy sheet. Required setup involves generator, horn, load cell, and die. Four amplitudes of 0, 3.68, 9.2, and 14.72 µm with three different horn speeds of 20, 50, and 80 mm/min were considered. Moreover, two processes of heat treatments, namely annealing and aging, have been applied. It was found that application of ultrasonic vibration generally improved bending parameters. Ultrasonic vibration reduced required bending force and also spring-back angle; with increasing amplitude of vibration, more reduction in force and spring-back angle was seen. Furthermore, at lower horn speed, the required force to bend the sheet metal was less than the case with higher horn speed. In addition, due to the low strength of the annealed aluminum alloy sheet metals (AA6061-O) in comparison with aged ones (AA6061-T6), less spring-back was observed in annealed sheet metals.

Ultrasonic vibration assisted tungsten inert gas welding of dissimilar metals 316L and L415

Ultrasonic vibration assisted tungsten inert gas welding was applied to joining stainless steel 316L and low alloy high strength steel L415. The effect of ultrasonic vibration on the microstructure and mechanical properties of a dissimilar metal welded joint of 316L and L415 was systematically investigated. The microstructures of both heat affected zones of L415 and weld metal were substantially refined, and the clusters of δ ferrite in traditional tungsten inert gas (TIG) weld were changed to a dispersive distribution via the ultrasonic vibration. The ultrasonic vibration promoted the uniform distribution of elements and decreased the micro-segregation tendency in the weld. With the application of ultrasonic vibration, the average tensile strength and elongation of the joint was improved from 613 to 650 MPa and from 16.15% to 31.54%, respectively. The content of Σ3 grain boundaries around the fusion line zone is higher and the distribution is more uniform in the ultrasonic vibration assisted welded joint compared with the traditional one, indicating an excellent weld metal crack resistance.

Weld structure of low-carbon structural steel formed by ultrasonic-assisted laser welding

The present study is aimed to examine the structure of a welded joint of low-carbon structural steel A 516–55 formed by melting under laser irradiation and by subsequent melt solidification. The main disadvantage of the weld structure in this steel is the formation of plate- and needle-like Widmanstätten ferrite in the conditions of ultra-fast heating and cooling which adversely affects the strength properties of the welded joints. It is shown that the application of ultrasonic vibrations during welding changes the melt solidification conditions and positively affects the dispersion of dendrites and growing Widmanstätten ferrite crystals.

The influence of ultrasonic elliptical vibration amplitude on cutting tool flank wear

In this article, the effect of vibration amplitude during ultrasonic elliptical vibration–assisted turning on cutting tool flank wear ( VBmax) and tool diffusion wear mechanism has been experimentally studied in machining of AISI 4140 hardened steel. To achieve this goal, an ultrasonic elliptical vibration–assisted turning setup was designed and manufactured. This device was then used in both ultrasonic-assisted tuning and ultrasonic elliptical vibration–assisted turning tests (i.e. one-dimensional and two-dimensional ultrasonic-assisted machining). According to the achieved results, ultrasonic elliptical vibration–assisted turning is more effective than ultrasonic-assisted tuning in reducing tool flank wear; at an amplitude of 13 μm, work velocity of 180 mm/s and feed of 0.09 mm/rev, VBmax were decreased 30.3% and 54.3%, respectively, in case of ultrasonic-assisted tuning and ultrasonic elliptical vibration–assisted turning. It was also observed that increasing the amplitude of ultrasonic vibrations reduces VBmax; at work velocity of 180 mm/s and feed of 0.09 mm/rev, the reduction of VBmax in ultrasonic elliptical vibration–assisted turning with amplitudes of 5 and 13 μm is, respectively, 39.3% and 54.3%, compared with that of conventional machining. The results also show that the application of ultrasonic vibrations weakens the cutting tool diffusion wear mechanism. This attenuation is much higher for ultrasonic elliptical vibration–assisted turning in comparison to ultrasonic-assisted tuning. Besides, the amount of attenuation in cutting tool diffusion wear mechanism decreases with increasing vibration amplitude.

Ultrasound effect on structure and properties of Cu–0.5Cr under upsetting

ABSTRACTWe studied the effect of the regimes of ultrasonic action on the structural transformation during free upsetting with 50% reduction of the copper alloy Cu–0.5Cr. In the process of deformation, the samples were subjected to intermittent and continuous ultrasonic actions. It can be noted that the application of ultrasonic vibrations in the process of deformation leads in both cases to a reduction in yield strength. Under a continuous ultrasonic action with a power of 640 W, the most developed structure is formed, with a fraction of high-angle boundaries equal to 32.4%, with the lowest values of coherent scattering regions, density of dislocations and microdistortions, while the decline in yield strength of the material under deformation is 40 MPa.This paper is part of a Thematic Issue on Copper and its Alloys.

High-Speed Rotary Ultrasonic Elliptical Milling of Ti-6Al-4V Using High-Pressure Coolant

High-speed rotary ultrasonic elliptical milling (HRUEM), as a novel ultrasonic vibration cutting method, has been introduced in milling the alloy Ti-6Al-4V. The application of ultrasonic vibration in high-speed milling can help open the cutting contact area intermittently. New cutting effects will happen with full use of the separation effect brought by ultrasonic vibration and the cooling effect brought by a high-pressure coolant (HPC). On the basis of that, this paper firstly introduces HPC into HRUEM of Ti-6Al-4V in the open literature and analyzes the tool-workpiece separation cooling mechanism in HRUEM, including kinematic analysis of tool tip trajectories, tool-workpiece separation principles and high-pressure coolant effects. We have conducted a comprehensive experimental study and the results show when HPC is increased to 200 bar, compared to conventional milling (CM), the tool life in HUREM can be extended by 6.6 times at 80 m/min, 4.2 times at 120 m/min and 2.4 times at 160 m/min. The maximum material removal volume (MRV) for a given new end mill in HRUEM is increased by 657% approximately. When the cutting speed is 80 m/min, the cutting temperature of the workpiece in HRUEM is reduced by 24.1% compared to that of CM. By applying the combination of HPC and tool-workpiece periodic separation, we can significantly enhance the cooling and lubrication efficiency in HRUEM and also inhibit the tool wear mode of adhesive wear typically occurred in CM.

Evolution of microstructure and phase composition of joints with ultrasonic-assisted resistance brazing

ABSTRACT Zn–2Al alloy is used as a filler metal for brazing of aluminium 6063 alloys by ultrasonic-assisted resistance brazing (RB) technology. The evolution of the microstructure and phase composition under the effects of the electric field and ultrasonic vibration were studied. The results show that ultrasonic cavitation can remove the existing oxide films effectively and inhibit element segregation, which help obtain joints with good metallurgical bonding. In comparison to RB joints, which exhibit a coarse dendritic structure, a uniform dendritic structure was obtained in the ultrasonic-assisted resistance joints. Furthermore, the combined electric and ultrasonic field has a significant effect on grain size and on dissolution during brazing. With the application of ultrasonic vibration, the diffusion between the base metal and the Zn–2Al filler metal intensifies.

Experimental investigation on surface quality in ultrasonic-assisted honing of 304 stainless steel

Honing is a surface finishing technology, which plays an important role in improving the surface quality and working performance of workpieces. However, with the extensive application of hard-to-machine materials and the increasing requirement for the surface properties of workpieces, the performance of conventional honing (CH) is becoming more and more difficult to meet the production needs. The ultrasonic vibration provides a way to overcome the technological constraints of CH and improve the machined surface properties. To realise the ultrasonic vibration of honing stone, a slotted block horn was used as a vibration transmission component and a supporting component of honing stone in this study. Finite element method was used to analyse and optimise the block horn to improve the uniformity of the amplitude on the output surface, to provide stable and efficient vibration for the honing stone. In this study, the effects of processing parameters on surface roughness in CH and ultrasonic-assisted honing (UAH) of stainless steel SUS304 were studied. The results indicated that the application of ultrasonic vibration in honing made a significant contribution to the formation of a dense punctiform morphology and reduction of the defects of the workpiece surface. Moreover, interactions between ultrasonic vibration, speed of revolution, and honing time in UAH make the changes of surface roughness much different from the CH. On the whole, for UAH, it is a feasible approach to improve the surface roughness by using a smaller amplitude, increasing the speed of revolution appropriately, and extending honing time.

Evolution of acoustic softening effect on ultrasonic-assisted micro/meso-compression behavior and microstructure

The application of ultrasonic vibration is an effective method to overcome the processing problems in micro/meso-forming. Previously it was observed that ultrasonic vibration could reduce flowing stress in the forming process, called ultrasonic volume effect. The volume effect contains multi-mechanisms such as stress superposition leading to apparent average stress reduction, acoustic softening and ultrasonic impact leading to real stress reductin. However, the evolutional characteristics and the mechanism of acoustic softening on material deformation is still not clear. And in most previous studies only the average stress but not the oscillatory stress was measured due to the convenience of dynamic force sensing system, which confused the different ultrasonic volume effects, acoustic softening, stress superposition and ultrasonic impact. The purpose of this study is to investigate the effects of acoustic softening on micro/meso-compression behavior and microstructure evolution. An ultrasonic-assisted compression test system with dynamic force sensing technology was developed. And a series of ultrasonic-assisted micro/meso-compression tests at different amplitudes were carried out on pure copper C1100O combining the microstructure analysis by EBSD technique. By analyzing the waveform of the oscillatory stress in the process, acoustic softening was successfully separated from the stress superposition and it was found that the deformation strain plays an important role on the effect of acoustic softening. The stress reduction by acoustic softening increases with the flowing strain or ultrasonic amplitude increasing. Besides, there is an evolutionary transition of acoustic softening ratio between small strain and large strain. When acoustic softening occurs, the low-angle grain boundaries distribute randomly in grains, compared to the piled distribution without ultrasonic assistance, implying motions of the low-angle grain boundaries or dislocation is improved by acoustic softening, resulting in the real stress reduction. In addition, with small deformation strain, the elongated grain becomes equiaxed and dislocation density is significantly reduced, which may be the result of the increased dislocation annihilation due to ultrasonic-induced dynamic recovery. However, with the deformation strain increasing to some extent, acoustic hardening gradually becomes significant, leading to much less effectiveness of acoustic softening on dislocation density reduction. The findings of this study provide an instructive understanding of the underlying mechanisms of acoustic softening in ultrasonic-assisted micro/meso-forming.

Ultrasonic vibration-assisted single point incremental forming of hemispherical shape using multi-stage forming strategy

Ultrasonic vibrations have found widespread engineering applications. The use of ultrasonic vibrations in machining and welding processes have reached the commercially viable stage. However, the application of ultrasonic vibrations in sheet metal forming applications is still in the research phase. This paper addresses the application of ultrasonic vibrations in a single point incremental forming process. The main focus of the paper is on the development of the ultrasonic vibration-assisted forming set-up customised to the vertical machining centre (VMC). Experiments have also been conducted with the developed set-up to produce the hemispherical shape which is difficult to form using a single-stage strategy using the single point incremental forming process. A multi-stage forming strategy has been used to form the hemispherical shape and the analysis of the results has been presented.

Ultrasonic vibration-assisted single point incremental forming of hemispherical shape using multi-stage forming strategy

Ultrasonic vibrations have found widespread engineering applications. The use of ultrasonic vibrations in machining and welding processes have reached the commercially viable stage. However, the application of ultrasonic vibrations in sheet metal forming applications is still in the research phase. This paper addresses the application of ultrasonic vibrations in a single point incremental forming process. The main focus of the paper is on the development of the ultrasonic vibration-assisted forming set-up customised to the vertical machining centre (VMC). Experiments have also been conducted with the developed set-up to produce the hemispherical shape which is difficult to form using a single-stage strategy using the single point incremental forming process. A multi-stage forming strategy has been used to form the hemispherical shape and the analysis of the results has been presented.

Investigation on machining characteristics of TC4 alloy by simultaneous application of ultrasonic vibration assisted milling (UVAM) and economical-environmental MQL technology

Abstract The optimization of machining methods is one of important guiding principles for achieving high-quality, cost saving and environmental protection machining of difficult-to-machine materials in modern manufacturing. Considering the principles and advantages of ultrasonic machining (UM) method and minimum quantity lubrication (MQL) technique, the simultaneous application of UM and MQL methods is anticipated to further improve machining performance in terms of cutting force, surface quality and chip morphology. Theoretical analysis indicates that the MQL system in UVAM could provide enhanced lubrication and cooling performance because of the separate-type cutting mechanism, the surface acoustic and the cavitation phenomenon of resonant workpiece in UM. Conventional milling (CM) trials, general UVAM trials and combined UVAM&MQL trials were conducted to investigate the effect of UVAM and MQL methods on machining performance of TC4 alloy, where the results of CM and general UVAM could provide indispensable reference. Multifaceted comparisons are presented in machining results of CM, UVAM and UVAM&MQL trials in terms of time-domain analysis and frequency-domain analysis of milling force, average cutting force, surface topography, surface profile and surface roughness. The results show that cutting force features could be significantly affected under UVAM and UVAM&MQL condition compared with that in general milling due to intermittent cutting mechanism and the coupling effect of UVAM and MQL methods. The uniform micro-textured surfaces with improved profile fluctuations could be obtained when applying the UVAM&MQL strategy. Compared with surface roughness in CM and UVAM, the surface roughness in UVAM&MQL is improved by about 30–50% and about 20–30%, respectively. The excellent machining performance demonstrates the feasibility and effectiveness of simultaneously applying UVAM and MQL methods.

Study on promotion of interface adhesion by ultrasonic vibration for CFRP/Al alloy joints

Adhesively bonded CFRP/Al joints have been widely used in various engineering fields. However, the poor interface adhesion between the adhesive and the Al adherend limits its further use. In this study, ultrasonic vibration was applied to promote the interface adhesion, and the promotion mechanism was studied in detail. The vibration was exerted on the surface close to the bonding area after the adhesive was applied. According to the bonding strength test, this process improved the bonding strength and repeatability by approximately 32% and 48%, respectively. By comparing the failure behavior without and with ultrasound, it can be seen that ultrasound promotes interface adhesion of the adhesive/Al adherend significantly. Under the application of ultrasonic vibration, a tight microscopic bond was formed at the bonding interface, and a chemical reaction occurred to form chemical bonds. The opening of the epoxy group was promoted to allow Al to react with –O–C to form Al–O–C, because attack of electrophilic Al + on O– of the epoxy group was strengthened by high-frequency impact between the adhesive and the Al adherend at the interface caused by the ultrasonic vibration. It can be seen that the application of ultrasonic vibration during the adhesive bonding process can promote interface adhesion between Al and the adhesive in terms of physics and chemistry, thus significantly improving the performance of the adhesive bond.

Microstructure and mechanical properties of ultrasonic assisted laser cladding Al2O3–ZrO2 ceramic coating

Al2O3–ZrO2 ceramic coatings were fabricated on titanium alloy substrate by ultrasonic assisted laser cladding. The effects of ultrasonic on the microstructure and mechanical properties of the coatings are investigated through experiments. A novel laser cladding method by ultrasonic assisted is used in this paper. In this method, ultrasonic waves are directly applied on the micro-zone of molten pool. Experimental results indicated that the grain size and mechanical properties of the coatings are improved with the ultrasonic assisted. The amount of coatings cracks are decreased due to the application of ultrasonic vibration in the laser cladding.