Stability Of Droplets Research Articles

Fast acoustic droplet ejection based on annular array transducer

Acoustic droplet ejection (ADE) has become the preferred method for liquid transfer in a variety of applications including synthetic biology, genotyping and drug discovery.Comparing with traditional pipetting techniques, the accuracy and data reproducibility of ADE based liquid transfer are improved, waste and cost are reduced, and cross-contamination is eliminated. The key component in the ADE system is the ultrasound transducer, which is responsible for generating focused ultrasound beam for droplet ejection. However, current ADE systems commonly utilize a single-element focused transducer with a fixed focal length that require mechanical movement to focus on the liquid surface, resulting in reduced liquid transfer efficiency. In this study, we first present a high-frequency annular array transducer for the ADE technology, which enables rapid and dynamic axial focusing to the liquid surface without mechanically moving the transducer, thereby accelerating liquid transfer. Experimental results show that the proposed 10 MHz, 5-element annular array transducer has good dynamic axial focusing ability, and can achieve accurate and stable droplet ejection of nanoliter volume at the designed focal length of 26–32 mm. Our results highlight the potential of the annular array transducer in advancing ADE system for rapid liquid transfer. This technology is expected to be useful in a variety of applications where precise and high-throughput liquid transfer is crucial.

Direct numerical simulation of a subcritical coaxial injection in fiber regime using sharp interface reconstruction

The numerical simulation of space launchers combustion chambers is a topic of increasing interest, as it may help the development of safer and more efficient designs. Understanding fuel injection is a particularly severe challenge. The liquid oxygen is injected by a round orifice surrounded by an annular gaseous stream of fuel, leading in subcritical conditions to a two-phase assisted atomization process. The result of this process is a very dense and polydisperse two-phase flow, which strongly influences the behavior of the chamber. Experimental investigation of this flow is difficult due to the axisymmetric geometry and the dense characteristic of the spray. Neither RANS nor Large Eddy Simulation (LES) possess reliable models able to reproduce the smallest scales of atomization, one of the reasons being the lack of relevant experimental data. Therefore, this work aims to provide detailed information on the atomization process using Direct Numerical Simulation. This paper presents a Direct Numerical Simulation (DNS) of a coaxial liquid–gas assisted atomization in the typical fiber regime encountered in cryogenic injectors. This study aims to better understand the evolution of liquid topology and extract relevant information that may help develop larger-scale models. The flow was first analyzed in terms of topology statistical data, using a dedicated detection and classification algorithm that could characterize the individual liquid structures. These include the central liquid core, the ligament created during primary atomization, and the spherical droplet obtained at the end of the atomization process. Subsequently, a more global statistical topology indicator was investigated, namely the interface area density distribution. This quantity is used in larger-scale RANS or LES models to predict the smallest scales of atomization. Therefore, understanding its behavior in a realistic case is of utmost importance. The interface area density distribution was correlated to the global jet behavior and the liquid topology data obtained by the detection algorithm. The results showed, in particular, a strong correlation between the initial increase of liquid–gas interface area density with the generation of ligaments and between the continuous decrease of the interface area density during droplet formation and stabilization.

Heterophase Pt/EG-catalyzed hydrosilylation in droplet microfluidics: Spectral monitoring and efficient 3D-printed reactors

Homogeneous Pt-catalyzed hydrosilylation is an industrially important process for the synthesis of organosilanes. Reusable heterophase (biphase) Pt-catalysts can solve economic and ecological issues arising from the high cost of Pt and its irretrievable “scattering”. Previously, we proposed a sustainable and convenient-to-handle heterophase Pt/EG-catalytic system (EG – ethylene glycol). In the current research heterophase Pt/EG-catalyzed hydrosilylation was transferred in a microfluidic regime that combined several advantages. A stable droplet or segmented Taylor flow with a well-defined contact area allow for the improvement of mass and heat transfer during the scaling of such a biphase and exothermic reaction, compared to batch mode. In situ Raman spectroscopy monitoring allows for fast and continuous data collection throughout the experiment and opens an opportunity for automation of conversion analysis. We demonstrate an efficient reaction of a range of reagents in the microfluidic reactor. In this work its universal components were constructed and modified using either commercially available units or via additive technologies (3D-printing). To the best of our knowledge, this is the first example of a semi-automatic recyclization device for a real heterophase catalytic process. These results open up new perspectives for scaling and automating industrially relevant heterophase hydrosilylation reactions.

On the stability of vortex quantum droplets

We discuss the stability of topological quantum droplets with the shape of two-dimensional soliton rings endowed with angular momentum that stem from a symmetric binary mixture in a Bose–Einstein condensate, with a strong trapping in one of the three spatial dimensions. We show that, in the lossless symmetric case, modeled by a Schrödinger equation with a Shannon-type nonlinear potential function, stable eigenstates can exist for arbitrarily large values of their topological charge l, provided the number of atoms is above a certain threshold. By comprehensive numerical computations, we analyze in detail cases up to l=50. We have found the perturbation modes and their eigenvalues, determining in each case which one dominates and destabilizes the solutions that lie below the stability threshold. We compare these results to the fate of the eigenstates that evolve in time. We also study the stability of the droplets under dynamical conditions by simulating collisions with potential barriers.

Development and optimization of a methimazole microemulsion for topical application: Formulation characteristics and transdermal permeation.

Methimazole, an oral antithyroid drug, has recently gained attention for its skin-brightening effects when applied topically to treat melasma. This study aims to develop, optimize, and characterize a methimazole microemulsion as a novel, safe approach for local melasma treatment. We prepared microemulsion formulations containing 3% methimazole by combining appropriate amounts of surfactants (Tween 80 and Span 20), propylene glycol cosurfactant, and an oil phase (oleic acid-transcutol p at a 1:10 ratio). We then assessed droplet size, stability, viscosity, and skin permeation using rat skin models. The microemulsions' droplet sizes ranged from 7.06 to 28.13 nm, with viscosities between 120 and 254 centipoises. Our analysis identified droplet size, viscosity, and membrane release as significant independent variables. We determined the permeability parameters of the optimal formulation through rat skin, including steady-state permeability rate (Jss), permeability coefficient (p), lag time (Tlag), and apparent diffusion coefficient (Dapp). We found that the microemulsions' characteristics, physicochemical properties, and invitro release depended on the surfactant-to-cosurfactant ratio, water content, and oil content. We developed an optimal formulation with a high surfactant-to-cosurfactant ratio and low water and oil percentages. This formulation shows potential for commercialization and manufacturing of final products.

Dewetting of a corner film wrapping a wall-mounted cylinder

In this study, we investigate the stability of a film that is attached to a corner between a cylinder and a substrate, using a combination of theoretical and numerical approaches. Notably, we place our focus on flat and thin films where the contact line is almost perpendicular to the cylinder wall whereas a small angle forms between the contact line and the substrate, and the film size is smaller than the cylinder radius. The film stability, which depends on the film size and the wall wettability, is first predicted by a standard linear stability analysis (LSA) within the long-wave theoretical framework. We find that the film size plays the most important role in controlling the film stability. Specifically, the thicker the film is, the less sensitive it becomes to the large-wavenumber perturbation. The wall wettability mainly impacts the growth rates of perturbations and slightly influences the marginal stability and postinstability patterns of wrapping films. We compare the LSA predictions with numerical results obtained from a disjoining pressure model (DPM) and volume-of-fluid (VOF) simulations, which provide more insights into the film breakup process. At the early stage there is a strong agreement between the LSA predictions and the DPM results. Notably, as the perturbation grows, thin film regions connecting two neighbouring satellite droplets form which may eventually lead to a stable or temporary secondary droplet, an aspect which the LSA is incapable of capturing. In addition, the VOF simulations suggest that beyond a critical film size, merging between two neighbouring drops becomes involved during the breakup stage. Therefore, the LSA predictions are able to provide only an upper limit on the final number of satellite droplets.

Rice protein hydrolysates as natural emulsifiers for an effective microencapsulation of orange essential oil by spray drying

This study aimed to identify the influence of rice protein hydrolysates (RPH) (degree of hydrolysis DH of 2, 6, and 10%) and rice protein isolate (RPI) on the formation and stabilization of the volatile oil droplets and to verify how protein hydrolysate affects the distribution of components on the surface and physicochemical properties of the spray-dried microparticles. In general, RPHs could reduce the interfacial tension (3.78–4.04 mN/m) compared to non-hydrolyzed protein (4.74 mN/m). However, no significant difference was observed between RPH samples. A positive correlation was observed between the interfacial tension and the oil droplet size, in which RPH emulsions showed 8.29–8.66 µm while RPI was 9.06 µm. DH influenced the surface composition of the spray-dried RPH emulsions. RPH10 powder showed a greater presence of protein (3.3%) on the particle surface and consequently exhibited high oil retention (50.0%). In contrast, this sample presented high hygroscopicity attributed to the protein surface. This study provides insights into differences between RPH powders, which can potentially impact the powder functionality and protection of the active compound.

Strongly Anisotropic Vortices in Dipolar Quantum Droplets.

We construct strongly anisotropic quantum droplets with embedded vorticity in the 3D space, with mutually perpendicular vortex axis and polarization of atomic magnetic moments. Stability of these anisotropic vortex quantum droplets (AVQDs) is verified by means of systematic simulations. Their stability area is identified in the parametric plane of the total atom number and scattering length of the contact interactions. We also construct vortex-antivortex-vortex bound states and find their stability region in the parameter space. The application of a torque perpendicular to the vorticity axis gives rise to robust intrinsic oscillations or rotation of the AVQDs. The effect of three-body losses on the AVQD stability is considered too. The results show that the AVQDs can retain the topological structure (vorticity) for a sufficiently long time if the scattering length exceeds a critical value.

Modulation of α-synuclein aggregation amid diverse environmental perturbation

Intrinsically disordered protein α-synuclein (αS) is implicated in Parkinson’s disease due to its aberrant aggregation propensity. In a bid to identify the traits of its aggregation, here we computationally simulate the multi-chain association process of αS in aqueous as well as under diverse environmental perturbations. In particular, the aggregation of αS in aqueous and varied environmental condition led to marked concentration differences within protein aggregates, resembling liquid-liquid phase separation (LLPS). Both saline and crowded settings enhanced the LLPS propensity. However, the surface tension of αS droplet responds differently to crowders (entropy-driven) and salt (enthalpy-driven). Conformational analysis reveals that the IDP chains would adopt extended conformations within aggregates and would maintain mutually perpendicular orientations to minimize inter-chain electrostatic repulsions. The droplet stability is found to stem from a diminished intra-chain interactions in the C-terminal regions of αS, fostering inter-chain residue-residue interactions. Intriguingly, a graph theory analysis identifies small-world-like networks within droplets across environmental conditions, suggesting the prevalence of a consensus interaction patterns among the chains. Together these findings suggest a delicate balance between molecular grammar and environment-dependent nuanced aggregation behavior of αS.

Modulation of α-synuclein aggregation amid diverse environmental perturbation.

Intrinsically disordered protein α-synuclein (αS) is implicated in Parkinson's disease due to its aberrant aggregation propensity. In a bid to identify the traits of its aggregation, here we computationally simulate the multi-chain association process of αS in aqueous as well as under diverse environmental perturbations. In particular, the aggregation of αS in aqueous and varied environmental condition led to marked concentration differences within protein aggregates, resembling liquid-liquid phase separation (LLPS). Both saline and crowded settings enhanced the LLPS propensity. However, the surface tension of αS droplet responds differently to crowders (entropy-driven) and salt (enthalpy-driven). Conformational analysis reveals that the IDP chains would adopt extended conformations within aggregates and would maintain mutually perpendicular orientations to minimize inter-chain electrostatic repulsions. The droplet stability is found to stem from a diminished intra-chain interactions in the C-terminal regions of αS, fostering inter-chain residue-residue interactions. Intriguingly, a graph theory analysis identifies small-world-like networks within droplets across environmental conditions, suggesting the prevalence of a consensus interaction patterns among the chains. Together these findings suggest a delicate balance between molecular grammar and environment-dependent nuanced aggregation behavior of αS.

Emulsification characteristics of crude oil with a high content of heavy components and its emulsification mechanism in porous media

There are occurrences of crude oil emulsification following the fracturing shut-in wells in the Jimushar, but the emulsification characteristics and mechanism remain unclear. In this study, the low-field nuclear magnetic resonance technique and visual microdisplacement tests are employed to investigate the emulsification characteristics of crude oil, along with its emulsification mechanism in porous media. Experimental results revealed that the heavy components (asphaltene and resin) enhance crude oil emulsification by increasing the viscous force of water droplets in the oil phase, affecting the size and stability of small water droplets in the oil phase. In the process of flowing through pore throats, emulsions are formed primarily by stretching and snap-off action, with stretching preferring to form smaller droplet-size emulsions, while snap-off results in the division of larger oil droplets into two smaller ones. The primary factors causing a large oil droplet to be stretched into smaller droplets include changes in the composition of the oil droplet, external tension, and the duration of these forces acting on the droplet. Capillary forces can emulsify crude oil and water at the pore scale, resulting in a reduction of the absorption rate. However, this rate can be restored when the capillary forces are strong enough for the water phase to penetrate and break through the emulsified layer. This study offers valuable insights into understanding the adaptability of the emulsification flooding mechanism.

Study on droplet transfer behavior and spattering mechanism in Mg-Gd-Y-Zr alloy regulated short circuit (Fronius CMT) welding

The quality, performance, and morphology of Mg-Gd-Y-Zr alloy regulated short circuit (Fronius CMT) welding components is directly depend on whether the droplet transfer process is stable. However, due to the inherent properties of the material, Mg-Gd-Y-Zr alloy is highly sensitive to heat input, and prone to spattering in the process of droplet transfer. In this work, three types of spattering were observed through high-speed cameras, which are caused by internal burst of droplet, wire withdrawal, and repelled transfer. Causal relationship of spattering mechanism and process parameter was explored especially in the stage of wire melting and droplet growth, and a simplified numerical model was used as an auxiliary means to further reveal the spattering of repelled transfer. The result indicated that the recoil pressure of metal vapor is the vital factor which destabilize the shape and motion trajectory of droplet and eventually caused spattering. The range of the process parameter for achieving a stable droplet transfer and well-formed weld bead is relative narrow which the peak current is recommended between 150 A to 170 A, and peak duration around 7 ms.

Minimal Peptide Sequences That Undergo Liquid-Liquid Phase Separation via Self-Coacervation or Complex Coacervation with ATP.

The simple (self-)coacervation of the minimal tryptophan/arginine peptide sequences W2R2 and W3R3 was observed in salt-free aqueous solution. The phase diagrams were mapped using turbidimetry and optical microscopy, and the coacervate droplets were imaged using confocal microscopy complemented by cryo-TEM to image smaller droplets. The droplet size distribution and stability were probed using dynamic light scattering, and the droplet surface potential was obtained from zeta potential measurements. SAXS was used to elucidate the structure within the coacervate droplets, and circular dichroism spectroscopy was used to probe the conformation of the peptides, a characteristic signature for cation-π interactions being present under conditions of coacervation. These observations were rationalized using a simple model for the Rayleigh stability of charged coacervate droplets, along with atomistic molecular dynamics simulations which provide insight into stabilizing π-π stacking interactions of tryptophan as well as arginine-tryptophan cation-π interactions (which modulate the charge of the tryptophan π-electron system). Remarkably, the dipeptide WR did not show simple coacervation under the conditions examined, but complex coacervation was observed in mixtures with ATP (adenosine triphosphate). The electrostatically stabilized coacervation in this case provides a minimal model for peptide/nucleotide membraneless organelle formation. These are among the simplest model peptide systems observed to date able to undergo either simple or complex coacervation and are of future interest as protocell systems.

The effects of droplet stabilization by surfactants and nanoparticles on leakage, cross-talk, droplet stability, and cell adhesion.

Partially fluorinated nanoparticles (FNPs) have been proposed as a promising alternative for stabilising aqueous droplets in fluorinated oils. The exceptional energetic stability of FNPs at the droplet interface holds the potential for minimising leakage, enhancing stability, and promoting improved cell adhesion. However, their lower diffusion coefficient compared to surfactants presents challenges in achieving rapid droplet stabilisation, which is important in microfluidics applications. While several studies have focused on some of these aspects, a comprehensive study and direct comparison with conventional fluorosurfactants is still missing. In this manuscript, we undertake an examination and comparison of four crucial facets of both FNP- and surfactant-stabilised droplets: leakage of compounds, emulsion stability, droplet formation dynamics and cell adhesion. Contrary to what has previously been claimed, our findings demonstrate that FNPs only reduce leakage and cross-talk in very specific cases (e.g., resorufin), failing to provide enhanced compartmentalisation for highly hydrophobic dyes (e.g., rhodamine dyes). On the other hand, FNP-stabilised droplets indeed exhibit greater long-term stability compared to their surfactant-stabilised counterparts. Regarding the size of droplets generated via a diversity of microfluidic methods, no significant differences were observed between FNP-stabilised and surfactant-stabilised droplets. Finally, the previously reported improvements in cell adhesion and spreading on FNP-stabilised interfaces is limited to flat oil/water (o/w) interfaces and could not be observed within droplets. These comprehensive analyses shed light on the nuanced performance of FNPs and commercial fluorosurfactants as stabilising agents for aqueous droplets in fluorinated oils, contributing valuable insights for choosing the correct formulation for specific droplet-based microfluidics applications.

Relationship between the interfacial properties of lactoferrin-(−)-epigallocatechin-3-gallate covalent complex and the macroscopic properties of emulsions

This study explored the relationship between the interfacial behavior of lactoferrin-(−)-epigallocatechin-3-gallate covalent complex (LF-EGCG) and the stability of high internal phase Pickering emulsions (HIPPEs). The formation of covalent bond between lactoferrin and polyphenol was verified by the increase in molecular weight. In LF-EGCG group, the surface hydrophobicity, interfacial pressure, and adsorption rate were decreased, while the molecular flexibility, interfacial film viscoelasticity, and interfacial protein content were increased. Meanwhile, LF-EGCG HIPPE possessed reduced droplet size, increased ζ-potential and stability. Rheology showed the viscoelasticity, structural recovery and gel strength of LF-EGCG HIPPE were improved, giving HIPPE inks better 3D printing integrity and clarity. Moreover, the free fatty acids (FFA) release of LF-EGCG HIPPE (62.6%) was higher than that of the oil group (50.1%). Therefore, covalent treatment effectively improved the interfacial properties of protein particles and the stability of HIPPEs. The macroscopic properties of HIPPEs were positively regulated by the interfacial properties of protein particles. The result suggested that the stability of emulsions can be improved by regulating the interfacial properties of particles.

1-Octanol-assisted ultra-small volume droplet microfluidics with nanoelectrospray ionization mass spectrometry

BackgroundDroplet microfluidics with push-pull and microdialysis sampling from brain slices, cultured cells and engineered tissues produce low volume mass limited samples containing analytes sampled from the extracellular space. This sampling approach coupled to mass spectrometry (MS) detection allows evaluation of time-dependent chemical changes. Our goal is an approach for continuous sampling and segregation of extracellular samples into picoliter droplets followed by the characterization of the droplets using nanoelectrospray ionization (nESI) MS. The main focus here is the optimization of the carrier oil for the microfluidic device that neither affects the stability of picoliter droplets nor compatibility with MS detection of a range of analytes. ResultsWe developed and characterized a 1-octanol-assisted ultra-small volume droplet microfluidic nESI MS system for the analysis of neurotransmitters in distinct samples including cerebrospinal fluid (CSF). The use of a 1-octanol oil phase was effective for generation of aqueous droplets as small as 65 pL and enabled detection of acetylcholine (ACh) and gamma-aminobutyric acid (GABA) in water and artificial CSF. Continuous MS analysis of droplets for extended periods up to 220 min validated the long-term stability of droplet generation and analyte detection by nESI-MS. As an example, ACh response demonstrated a linear working range (R2 = 0.99) between 0.4 μM and 25 μM with a limit of detection of 370 nM (24 amol), enabling its quantitation in rodent CSF. SignificanceThe established droplet microfluidics – nESI MS approach allows the analysis of microenvironments at high spatiotemporal resolution. The approach may allow microsampling and monitoring of spatiotemporal dynamics of neurochemicals and drugs in the brain and spinal cord of live animals.

Investigating the effects of oil type, emulsifier type, and emulsion particle size on textured fibril soy protein emulsion-filled gels and soybean protein isolate emulsion-filled gels.

The effects of oil type, emulsifier type, and emulsion particle size on the texture, gel strength, and rheological properties of SPI emulsion-filled gel (SPI-FG) and TFSP emulsion-filled gel (TFSP-FG) were investigated. Using soybean protein isolate or sodium caseinate as emulsifiers, emulsions with cocoa butter replacer (CBR), palm oil (PO), virgin coconut oil (VCO), and canola oil (CO) as oil phases were prepared. These emulsions were filled into SPI and TFSP gel substrates to prepare emulsion-filled gels. Results that the hardness and gel strength of both gels increased with increasing emulsion content when CBR was used as the emulsion oil phase. However, when the other three liquid oils were used as the oil phase, the hardness and gel strength of TFSP-FG decreased with the increasing of emulsion content, but those of SPI-FG increased when SPI was used as emulsifier. Additionally, the hardness and gel strength of both TFSP-FG and SPI-FG increased with the decreasing of mean particle size of emulsions. Rheological measurements were consistent with textural measurements and found that compared with SC, TFSP-FG, and SPI-FG showed higher G' values when SPI was used as emulsifier. Confocal laser scanning microscopy (CLSM) observation showed that the distribution and stability of emulsion droplets in TFSP-FG and SPI-FG were influenced by the oil type, emulsifier type and emulsion particle size. SPI-stabilized emulsion behaved as active fillers in SPI-FG reinforcing the gel matrix; however, the gel matrix of TFSP-FG still had many void pores when SPI-stabilized emulsion was involved. In conclusion, compared to SPI-FG, the emulsion filler effect that could reinforce gel networks became weaker in TFSP-FG.

Preventing emulsification during rare earths solvent extraction by the addition of Span 80 to enhance the interfacial stability of the P507 oil droplets

The demand for rare earth elements is increasing daily with rapid economic development, thereby increasing the requirements for its separation and purification technologies. The major method for purification and separation of rare earth elements in the industry is currently solvent extraction. In the actual production process, emulsification often occurs because of improper control of the organic phase, aqueous phase properties or operating conditions, and resulting in resource wastage and environmental pollution. This has become an issue that restricts the development of the rare earths industry. To prevent emulsification during rare earths solvent extraction, the organic structure of the P507-kerosene solution was regulated by the addition of Span 80 as a regulator. This study investigated the effects of Span 80 content, P507 concentration, saponification degree and the amount of pre-loading rare earth elements in the organic phase after adding Span 80 on the extraction efficiency of Er3+ and oil content in the raffinates. The results demonstrated that when the content of Span 80 was 6 %, the saponification degree of P507 in the organic phase was 10 %, the concentration of Er3+ in the aqueous phase was 0.5 g /L, the pH value in the aqueous phase was 3, the phase ratio (VO: VA) was 1:2, the extraction efficiency could still reach more than 99 %, and the oil content in the raffinates was 13.9 mg/L. The results demonstrated that the final extraction efficiency did not decrease; however, the extraction rate of rare earth elements did. Further, the oil content in the raffinates decreased greatly after the addition of Span 80. The mechanism was investigated using Fourier-transform infrared (FTIR) spectroscopy and atomic force microscopy (AFM). The interfacial stability of P507 oil droplets was enhanced by the addition of Span 80. Emulsification was, thus, effectively prevented and the dissolution loss of the organic phase was greatly reduced. The results provide a novel method for preventing emulsification during rare earths extraction at the source, and a novel idea for preventing resource loss and protecting the ecological environment.

Analysis of drop-on-demand printing characteristics and stability driven by inertial forces

As the core technology in the field of microdroplet related applications, researchers have been striving to develop new driving methods and improve the stability of inkjet printing technology to meet the diverse needs of various materials and applications. In this study, a novel, simple, and cost-effective droplet printing method based on inertial force driving is proposed, and its printing characteristics and stability are investigated through experimental and numerical simulation studies. A numerical model was developed to explore the effects of operating parameters and fluid properties on the printing process. The results showed that for a given fluid, it is easier to form satellite droplets when driven from a smaller nozzle with higher voltage and pulse width. The hydrophilic nature of the nozzle can suppress the formation of satellite droplets, but it is prone to retain liquid, thereby affecting the next printing effect. Under certain operating conditions, fluids with lower density, higher viscosity, and higher surface tension are difficult to be driven but can suppress the formation of satellite droplets and promote printing stability. Finally, a parameter space composed of dimensionless numbers Op representing operating parameters and Z representing fluid properties (reciprocal of the Oh number) was established to investigate the comprehensive influence on the printing. The correctness of this parameter space in guiding the selection of parameters for stable droplet printing was validated through experiments.

Microstructure and properties of SiC ceramic-modified aluminium alloy fabricated using wire arc additive manufacturing

A method for improving the properties of the deposited metal in wire arc additive manufacturing of Al–Si alloy is proposed here, which introduces SiC ceramic particles into the side-axis wire feed. The effects of SiC ceramic particles on the macroscopic morphology, microstructure and mechanical properties, corrosion resistance, and wear resistance of deposited metals were studied. The results show that the introduction of SiC particles will not affect the surface-forming quality of the deposited metal; this is likely due to the stable droplet transfer and no splashing. The transverse and longitudinal tensile strengths are increased by 10.1 % and 11.3 %, respectively, while the corresponding elongations are increased by 33.1 % and 47.2 %, respectively. Further, the corrosion resistance and wear resistance of Al–Si alloy deposited metals containing SiC are improved. The (100) base surface has strong texture characteristics along the deposition direction X0, and the maximum polar density decreases to 13.63, which indicates that SiC promotes the transformation of columnar crystals to equiaxial crystals. The interface between SiC and Al is non-coherent, and the performance improvement lies in the enhanced dispersion distribution and load transfer of SiC. A ring structure was prepared using double-wire arc additive manufacturing technology, and the feasibility of side-axis wire feeding technology was verified.