Ultrasonic-assisted Process Research Articles

Microstructure and formation mechanism of Al2O3/Zn5Al/2024Al joint by ultrasonic assisted soldering process

Zn5Al filler metal was used to join 2024Al and Al2O3 ceramic with the ultrasonic assisted soldering process in the atmospheric environment. Al2O3 ceramics were dipped by molten Zn5Al alloy (melting temperature: 382 °C) with the time of ultrasonic action for 5– 600 s, respectively. During the ultrasonic assisted soldering process, the ultrasonic was applied for 1 s, the Al2O3 ceramic was subjected to a pressure of 0.2 MPa. To reduce the residual stress, the soldered joint was cooled in the furnace. 2024Al had better metallurgical fusion with Zn5Al filler metal. The grain boundary on the 2024Al was partially dissolved by Zn5Al filler metal. The fan-shaped α-Al eutectic phases were distributed on the gradient layer. With the increase of the ultrasonic dipping time, more fine β-ZnAl phases were accumulated on the Al2O3 ceramic surface. The Al2O3/Zn5Al/2024Al joint with ultrasonic dipping time of 600 s had the highest shear strength (39.53 MPa). The soldered joint fractured mainly in cohesive failure mode, and the joint broke from the Zn5Al filler metal.

On surface integrity of Hastelloy C-276 using chemo based ultrasonic assisted magnetic abrasive finishing process

On surface integrity of Hastelloy C-276 using chemo based ultrasonic assisted magnetic abrasive finishing process

Enhancing processed quality of roasted eel with ultrasound treatment: Effect on texture, taste, and flavor

To enhance processed quality, ultrasound treatment was used in eel products processing. This study aimed to investigate the effects of ultrasonic power on the processed quality of roasted eel. Prior to toasting, eel muscle was treated with ultrasonic power from 0 W to 1000 W. Results showed that the highest water content (80.0%) was produced with 600 W ultrasound. Ultrasound above 400 W increases the hardness and chewiness of (p < .05). The SEM results illustrated the application of ultrasound promoted a more porous and homogeneous network. 600 W ultrasound can increase the umami amino acids, and enhance the content of adenosine monophosphate (p > .05) and inosine monophosphate (p < .05). Thiobarbituric acid was increased by ultrasound, especially over 600 W (p < .05). Polyunsaturated fatty acids changed greatly due to the ultrasound treatment (42.50% ~ 38.91%). Samples treated with 400 ~ 600 W had the most abundant volatile organic compounds. In conclusion, ultrasound treatment especially within 600 W enhanced the processed quality of roasted eel. Novelty impact statement This work further investigates effect of ultrasonic power on processed quality of roasted eel in ultrasonic assisted processing, including the influences on texture, taste and flavor. The application of ultrasound helped to obtain a more porous and homogeneous network. Meanwhile, ultrasound treatment can increase protein degradation and lipid oxidation, and finally promote the formation of umami contents and volatile organic compounds.

Enzymatic transesterification of Rubber Seed Oil Using Immobilized Pseudomonas Cepacia Lipase

Biodiesel or Fatty acid methyl ester (FAME) is a biofuel formed from transesterification of vegetable oil and fat. In this study, the source of vegetable oil is Rubber seed oil (RSO). The oil was extracted from rubber seed by solvent extraction, using n-hexane and methanol. The oil produced from both solvents’ extraction were used as feedstock. Biodiesel production from RSO was performed with methanol as acyl acceptor. using immobilized Pseudomonas cepacia lipase as catalyst. Three different parameters were studied, they are reaction time, lipase inhibition, and stepwise addition of methanol/oil molar ratio. The enzymatic transesterification with ultrasonic assisted process was utilized, as it enhances the miscibility between oil and methanol, which lead to reducing the reaction time and significantly increased the yield of biodiesel. The results indicated a significant biodiesel is produced with the highest yield of 76.55%, at 45 °C, with the lipase amount of 5 % (w/w), methanol to oil molar ratio of 3:1 within 6 hours. It is found that despite high content of free fatty acid of rubber seed oil, it has a potential as alternative feedstock for FAME production.

Graphene Nanoplatelets Modified Chemlok® Adhesive System for Natural Rubber – Aluminium Bonded Component in Engine Mount

Generally, the engine mount is made from rubber and mild steel bonded with a Chemlok® adhesive system. It could be modified to provide sufficient bonding between natural rubber and aluminum. Therefore, this work aims to study a nano-manipulated adhesive system by modifying the existing Chemlok® adhesive system at different weight percentages of graphene nanoplatelets (GNPs) loading via two steps ultrasonic-assisted stirring process by ultrasonic bath and hot plate. The natural rubber (NR)-aluminum (Al) substrates were bonded using a hot press machine under the pressure of 100 kgf/cm2 for 20 minutes at 140 °C temperature. The samples were subjected to a 90-degree peel test based on ASTM D429 by the UTM machine, and the peel-fractured surfaces were evaluated both physically and under SEM. The adhesive strength increased with the increment of GNPs in the modified Chemlok® 205/220 system. The GNPs modified Chemlok® system achieved 30% improvement than the existing adhesive. The analyses proved the modification was successful. The modified system with GNPs dispersed at certain intercalation levels showed active functional groups, reinforcing effects, and thermal stability.

Towards understanding the ploughing friction mechanism in ultrasonic assisted grinding with single grain

Despite the widespread use of ultrasonic vibration in machining (i.e., grinding) due to friction reduction, the friction mechanism at the tool-workpiece contact is still unclear. Most of the explanations focus on the kinematic analysis, but few attempts have been made to understand the deformation process of the tool-workpiece contact under ultrasonic vibration. This work presents a novel prediction model to calculate the ploughing friction coefficient with the two-dimensional ultrasonic vibration assistance (imposed transverse vibration and additional normal vibration). Considering the ploughed surface generation, the actual contact area and the distribution of friction stress could be predicted. Particularly, the instantaneous contact area with a complex motion path was solved by generating the ploughed surface and calculating the overlapping area of the particle geometry engaged with the generated groove. Experimental results agree well with the predicted results. In addition to the deflection of resultant velocity, the friction reduction is also attributed to the change in friction stress distribution due to three special contact states. This research can deepen the understanding of tool-workpiece friction reduction mechanism in ultrasonic assisted grinding and might provide an important reference for studying other ultrasonic assisted machining processes.

The dynamic recrystallization mechanism of ultrasonic power on non-contact ultrasonic-assisted direct laser deposited alloy steel

Ultrasonic assistance has been used as one of the more convenient and effective means of grain refinement during alloys direct laser deposition, and the formation of fine grains is closely related to the dynamic recrystallization behavior during laser non-equilibrium metallurgy. To investigate the dynamic recrystallization behavior of the non-contact ultrasonic-assisted process in direct laser deposited alloy steel, this paper used 24CrNiMoY alloy powder and the non-contact ultrasonic-assisted direct laser deposition method to study the mechanism of ultrasonic power on the dynamic recrystallization behavior of alloy steel. The results show that the ultrasonic power had an obvious regulation on the prepared alloy steel samples’ grain size and tensile properties. The microstructure of the prepared samples was mainly composed of upper bainite, lower bainite, and granular bainite. After the non-contact ultrasonic-assisted process, the grain was obviously refined, and the smallest grain was 0.4 μm. The dynamic recrystallization behavior in direct laser deposited alloy steel at different non-contact ultrasonic powers was mainly determined by dislocation density and solidification rate. The introduction of non-contact ultrasonic caused dislocation movement in the plastic deformation zone of direct laser deposited alloy steel samples, and the low angle grain boundaries migration—subgrain growth—the transformation of low angle grain boundaries to high angle grain boundaries initiated by dislocation movement was the key process to trigger dynamic recrystallization. The optimized ultrasonic power of 360 W had the best strength-plasticity matching relationship for the prepared samples, with a tensile strength of 1108 MPa and elongation of 12%. And the strong-plastic product of sample (360 W) was increased from 6 GPa% to 13 GPa% due to the increase of recrystallization fraction. This study provides a valuable theoretical and technical reference for preparing high-performance alloy steel by ultrasonic-assisted direct laser deposition.

Influence Mechanism of Ultrasonic Vibration Substrate on Strengthening the Mechanical Properties of Fused Deposition Modeling.

Fused deposition modeling is the most widely used 3D-printing technology, with the advantage of being an accessible forming process. However, the poor mechanical properties of the formed parts limit its application in engineering. Herein, a new ultrasonic-assisted fused deposition modeling 3D-printing method was proposed to improve the mechanical properties of the formed parts. The effects of ultrasonic vibration substrate process parameters and printing process parameters on the tensile and bending properties of formed samples were studied. The tensile strength and bending strength of the samples printed with a 12 μm ultrasonic amplitude can be increased by 13.2% and 12.6%, respectively, compared with those printed without ultrasonic vibration. The influence mechanism of ultrasonic vibration on mechanical properties was studied through microscopic characterization and in situ infrared monitoring experiments. During the printing process, increasing the ultrasonic vibration and temperature employed via the ultrasonic substrate can reduce the pore defects inside the sample. The mechanical properties of FDM-formed samples can be controlled by adjusting ultrasonic-assisted process parameters, which can broaden the application of 3D printing.

Research on Ultrasonic-Assisted Grinding Process of SiCp/Al Composites

SiCp/Al is a kind of particle reinforced composites with good material properties, which can be used in the field of lightweight parts and electronic packaging. Ultrasonic- assisted grinding process is one of the processes which is suitable for machining hard and brittle materials, the surface quality can be improved by using appropriate ultrasonic-assisted process parameters. In this paper, the ultrasonic-assisted grinding process is used to improve the surface quality of SiCp/Al, meanwhile, the kinematics of abrasive particles in grinding is analysed to explain the effect of ultrasonic vibration. In addition, ultrasonic-assisted grinding experiment of SiCp/Al is conducted, it is found that the axial ultrasonic vibration can improve the surface quality of SiCp/Al in grinding, and the reduction percentage is up to 8.20% compared to the normal grinding. In addition, a regression model is proposed for surface roughness prediction, the result of t-test on the residuals shows that the model is accurate.

Ultrasonic-assisted fabrication of Cs2AgBiBr6/Bi2WO6 S-scheme heterojunction for photocatalytic CO2 reduction under visible light

In this manuscript, Cs2AgBiBr6/Bi2WO6 nanocomposites was fabricated via an ultrasonic-assisted process. The activity of the as-obtained Cs2AgBiBr6/Bi2WO6 nanocomposites for photocatalytic CO2 reduction was studied under visible light. The as-obtained Cs2AgBiBr6/Bi2WO6 nanocomposites show a superior activity for photocatalytic CO2 reduction to produce CH4 and CO, with an optimum activity achieved over 0.5 Cs2AgBiBr6/Bi2WO6. The obvious superior activity observed over Cs2AgBiBr6/Bi2WO6 nanocomposites as compared with bare Cs2AgBiBr6 and bare Bi2WO6 as well as a mechanical mixture of Cs2AgBiBr6 and Bi2WO6 can be owe to the fabrication of an efficient S-scheme heterojunction, which accelerates the separation of the photogenerated charge carriers in Cs2AgBiBr6 and Bi2WO6 without sacrificing the high redox capability of Cs2AgBiBr6 and Bi2WO6. This work demonstrates that the coupling of two photocatalytic materials with staggered band alignment to form an S-scheme heterojunction is an effective strategy to develop efficient photocatalytic systems and also highlights the promising role of using lead free perovskites in photocatalysis.

Ultrasonic-Assisted Laser Metal Deposition (LMD) of Steel 316L

The parts produced by Laser Metal Deposition (LMD) usually contain deposition defects such as pores, cavities and micro-cracks, which have a negative influence on the quality and mechanical properties. This work examines the use of ultrasonic vibrations to reduce the most common deposition defects. A series of tests are carried out (with and without ultrasonic assistance) to obtain comparative values. These values are analysed for particular purposes and the results show that the ultrasonic-assisted process leads to higher efficiency in powder utilization. Pores and micro-cracks are successfully reduced and crystal grains are visibly refined. However, the improvement of these geometric and microstructural properties does not lead to an increase in tensile strength and hardness. The fundamental investigation presented in this work proves that ultrasonic wave contributes to an efficient and effective LMD process.

Investigation of microstructure evolution and mechanical properties of 2024 Al/Al2O3 ceramic joints

Low-temperature solder was used to join 2024 Al and Al2O3 ceramic by an ultrasonic-assisted soldering process. Strong bonding between solder alloy and Al2O3 ceramic could be obtained when the reactive wetting happened. Al2O3 was formed during the reactive wetting process, and it is supposed to determine the joining strength of 2024 Al/Al2O3 ceramic joints. The increase of product Al2O3 strengthened the bonding of solder and Al2O3 ceramic. To improve the mechanical behaviour of 2024 Al/Al2O3 ceramic joints, SHBF160 glass powder was added to solder to strengthen the bonding between solder and Al2O3. The shear strength of 2024 Al/Al2O3 ceramic joint increased to 69 MPa owing to the positive reinforcement of glass powder.

Ultrasonic-Assisted Brazing of Titanium Joints Using Al-Si Based Fillers: Numerical and Experimental Process Design

The ultrasonic-assisted brazing process was studied both numerically and experimentally. The ultrasonic brazing system was modeled by considering the actual brazing conditions. The numerical model showed the distribution of acoustic pressure within the filler and its variations according to the gap distance at different brazing temperatures. In the experimental part, brazing joints were studied and evaluated under multiple conditions and parameters. Although either the initial compression load or the ultrasonic vibration (USV) can initiate the interaction at the interface, the combined effect of both helped to produce joints of a higher quality with a relatively short brazing time, which can be further optimized in terms of their mechanical strength. The effect of the Si content on the joint interface, and the effect of the brazing conditions on the microstructures were studied and discussed.

Mechanism and Experiment Study of Non-Contact Ultrasonic Assisted Grinding

Ultrasonic-assisted grinding processing can effectively reduce the surface roughness and enhance the processing efficiency in the processing of hard and brittle materials. However, the most common ultrasonic assisted grinding is a type of contact ultrasonic grinding where the grinding tool directly contacts the workpiece, which means that it is necessary to accurately control the pre-pressure of the grinding tool on the workpiece. The control of pre-pressure will inevitably increase the complexity of the grinding device, and it is easy to wear the workpiece because of improper pre-pressure control. In this paper, a non-contact ultrasonic grinding method is proposed and the machining mechanism of non-contact ultrasonic grinding is revealed. The resonant frequency of the ultrasonic vibration system and vibration amplitude of the grinding tool working face were simulated and experimentally tested, respectively. Then, the experiment of non-contact ultrasonic grinding of a sapphire wafer was carried out. The result showed that non-contact ultrasonic grinding of the sapphire wafer could reduce the surface roughness by 48.6%. Compared with traditional contact grinding of sapphire wafer under certain pre-pressure conditions, the experimental results show that non-contact ultrasonic grinding has better effects in reducing surface roughness, improving processing efficiency, and improving the quality uniformity of the workpiece machining surface.

Self-heating properties of iron oxide nanoparticles prepared at room temperature via ultrasonic-assisted co-precipitation process

ABSTRACT Preparation of iron oxide nanoparticles by a simple and environmentally friendly technique with high hyperthermia performance is highly desirable for biomedical application. These can potentially develop room temperature nanoparticles through the ultrasonic-assisted co-precipitation process. In this work, two types of iron oxide nanoparticles, un-coated iron oxide (IONPs) and coated iron oxide nanoparticles with tetraethoxysilane (IONPs-TEOS), were prepared at room temperature via ultrasonic-assisted co-precipitation process. The prepared nanoparticles were characterized using multiple techniques, such as Fourier transform infrared spectroscopy (FTIR), Thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM), dynamic light scattering (DLS), zeta potential, scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), and X-ray diffraction (XRD). Self-heating properties and heating efficiency of the prepared nanoparticles were investigated under an alternative magnetic field in the function of carriers’ viscosity (water and ethanol) and induction time (0–6 minutes). It was found that the highest specific absorption rate (SAR) value for IONPs was 22.9 W/g when using water as a carrier. The viscosity affects the heating properties by changing the carrier through a Brownian mechanism and thus causes a significant SAR. Brownian relaxation is hindered by the particle’s hydrodynamic volume and the viscosity that tends to inhibit the particle rotation in the medium. Hence, the prepared room temperature iron oxide nanoparticles by this route can be applicable as hyperthermic agents for biomedical applications.

Ultrasonic dispersion method used in glass polishing experiment

To solve the problems of low processing efficiency and poor glass surface quality when using rare earth polishing powder to grind super-hard K9 glass. The potential, phase structure, surface morphology, and particle size distribution of the nano-rare earth polishing powder were characterized. Compare the evaluation indexes such as polishing efficiency, surface morphology, and contact angle after the polishing process is changed. The results of the comparative study show that the average surface roughness of the glass after heating ultrasonic polishing process is 0.9064 nm, the polishing rate reaches 0.748 μm/min, the average surface roughness of the glass without heating ultrasonic polishing process is 1.3175 nm, and the polishing rate reaches 0.586 μm/min, the ultrasonic assisted polishing process is superior to the conventional polishing process. The heating ultrasonic method provides experimental basis for precise and rapid processing.

Ultrasonic-assisted soldering of aluminium and copper with Sn–Zn–Bi–Ag solder

The effects of ultrasonic-assisted soldering parameters on the interfacial microstructural evolution and shear strength of designed Al/Sn–9.77Zn–11.36Bi–1.46Ag/Cu solder joints were investigated. The ultrasonic-assisted soldering process promoted the dissolution of Al substrate and roughed Al/solder interface, which improved the pinning effect of Sn–9.77Zn–11.36Bi–1.46Ag on Al substrate. With an increasing ultrasonic soldering temperature, time and power, more Al atoms dissolved from Al substrate and migrated across solder to the opposite Cu substrate to form Al-rich (Zn) solid solutions. Consequently, Al4.2Cu3.2Zn0.7 formed between ϵ-AgZn3 and Cu5Zn8 layers at Cu substrate, resulting in thinner Cu5Zn8 and higher shear strength of solder joints. The highest shear strength of solder joints (38.6 MPa) was achieved after ultrasonic-assisted soldering at 300°C for 10 s under 9 W.

Process intensification for synthesis of triglycerides of capric acid using green approaches

The present research focuses on intensified synthesis of tricaprin by esterification reaction between capric acid and glycerol catalysed by dry amberlyst-15 using ultrasonication approach. Effect of several reaction conditions like molar ratio, reaction temperature, and amberlyst-15 loading on the rate of conversion has been studied. Effect of ultrasonic conditions like duty cycle and irradiation time on the intensified synthesis is investigated. Recyclability of amberlyst-15 is studied to make process more economical. It is investigated that the optimum reaction conditions which gave maximum conversion of 95% were molar ratio of capric acid: glycerol as 3:5, reaction temperature 90 ​°C, 4% amberlyst −15 loading. It was further investigated that ultrasonic conditions which gave intensified synthesis were 70% duty cycle and irradiation time of 120 ​min. The ultrasonic assisted process was compared with conventional synthesis. Conventional synthesis gave 30% yield in 120 ​min and 82% in 18 ​h. Amberlyst-15 was successfully reused for 13 cycle without any change in the conversion (%) of reaction.

Phytochemical Analysis, Antioxidant and Antimicrobial Screening of Seriphidium Oliverianum Plant Extracts.

The aim of this study was to investigate the phytochemicals using reverse-phase high pressure liquid chromatography (RP-HPLC), antioxidant, antifungal and antibacterial activities of Seriphidium oliverianum stem extracts. The extraction was carried out by conventional shaking process (CSP) and ultrasonic assisted process (UAP). The highest total phenolic contents (97.85 ± 0.735 mg gallic acid equivalent (GAE)/g sample) and flavonoid contents (188.15 ± 0.53 mg catechin equivalent (CE)/g sample) were found in methanol extract obtained by CSP. Antioxidant activity was investigated using DPPH° scavenging assay and reducing power assay. Methanol extract using UAP showed the highest DPPH° scavenging activity (79.95% ± 1.80%) followed by methanol and butanol extracts obtained through CSP. Moreover, methanol extracts using CSP showed highest reducing activity (1.032 ± 0.0205 absorbance). In-vitro antimicrobial activity was studied using most common infection causing fungal and bacterial strains. Anti-fungal activity of methanol extract using CSP showed the highest zone of inhibition (10.5 mm) against F. avenaceum fungal strain, while aqueous extracts obtained through showed the highest antibacterial activity (22 ± 1.32 mm zone of inhibition) against S. aureus. The results showed that the methanol stem extract of S. oliverianum is a valued candidate for further screening and could be processed for in-vivo infection induced animal trials.

Ultrasonic assisted exfoliation for efficient production of RuO2 monolayer nanosheets

RuO2 monolayer nanosheets can be easily synthesized by an ultrasonic assisted exfoliation process.