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The slippery liquid infused porous surface has developed into a potential technology to solve the problem of poor durability in corrosion resistance. Herein, a kind of slippery liquid infused porous surface is created on 7075 aluminum alloy by wire electrical discharge machining for corrosion resistant applications. The hardness of the constructed porous microstructure is similar to the aluminum alloy substrate material, which ensures the stability of the slippery liquid infused porous surface. The modification of low surface energy substance fluorosilane avoids the direct contact between corrosive liquid and porous surface, and improves the lyophobic performance of the porous microstructure surface. The corrosion resistance of the porous microstructure surface is enhanced by the injection of perfluorinated lubricating oil. The experimental results show that the created slippery liquid infused porous surface can display super-slippery properties and durable corrosion resistance. The average sliding velocity of a water droplet is 0.48 ± 0.05 mm s−1 at a sliding angle of 5°. The corrosion current density of the surface is 3.116 × 10−6 A cm−2, which is 2 orders of magnitude lower than that of the polished surface. And the impedance radius reaches 90 kΩ cm2, which is about 20 times that of the polished surface.

Many biological surfaces with the multi-scale microstructure show obvious anisotropic wetting characteristics, which have many potential applications in microfluidic systems, biomedicine, and biological excitation systems. However, it is still a challenge to accurately prepare a metal microstructured surface with multidirectional anisotropy using a simple but effective method. In this paper, inspired by the microstructures of rice leaves and butterfly wings, wire electrical discharge machining was used to build dual-level (submillimeter/micrometer) periodic groove structures on the surface of titanium alloy, and then a nanometer structure was obtained after alkali-hydrothermal reaction, forming a three-level (submillimeter/micrometer/nanometer) structure. The surface shows the obvious difference of bidirectional superhydrophobic and tridirectional anisotropic sliding after modification, and the special wettability is easily adjusted by changing the spacing and angle of the inclined groove. In addition, the results indicate that the ability of water droplets to spread along parallel and perpendicular directions on the submillimeter groove structure and the different resistances generated by the inclined groove surface are the main reasons for the multi-anisotropic wettability. The research gives insights into the potential applications of metal materials with multidirectional anisotropic wetting properties.

Reducing the contact time of a water droplet on non-wetting surfaces has great potential in the areas of self-cleaning and anti-icing, and gradually develops into a hot issue in the field of wettability surfaces. However, the existing literature on dynamic behavior of water drops impacting on superhydrophobic surfaces with various structural shapes is insufficient. Inspired by the microstructure of lotus leaf and rice leaf, dual-level and three-level structures on plane and convex surfaces were successfully fabricated by wire electrical discharge machining on aluminum alloy. After spraying hydrophobic nanoparticles on the surfaces, the plane and convex surfaces with dual-level and three-level structures showed good superhydrophobic property. Bouncing dynamics of impact droplets on the superhydrophobic surfaces wereinvestigated, and the results indicated that the contact time of plane superhydrophobic surface with a three-level structure was minimal, which is 60.4% less than the plane superhydrophobic surface with dual-level structure. The effect of the interval S, width D, and height H of the structure on the plane superhydrophobic surface with three-level structure on contact time was evaluated to obtain the best structural parameters for reducing contact time. This research is believed to guide the direction of the structural design of the droplet impinging on solid surfaces.

Many biological surfaces with hierarchical microstructures exhibit obvious fog collection abilities. However, it is difficult to effectively fabricate a microstructured metal surface with fog collection performance using a simple but flexible method. Inspired by the abilities of microstructures of Sarracenia trichomes to capture fog and transport water, a series of hierarchical groove surfaces with the fog collection property were fabricated by wire electrical discharge machining (WEDM) method, and the fabricated surfaces showed the obvious superhydrophilicity. Moreover, the results show that the fabricated surface with the hierarchical groove structure had better water transport performance and higher fog collection efficiency compared with the smooth surface, and the abilities of water transport and fog collection are related to the number of low ribs on the surface with the hierarchical microgroove. The microstructure metal materials obtained in this study not only open up the potential applications of WEDM in fog collection, but also have wide application prospects in the fields of microfluidic system, biomedicine, and biological excitation system.

Ti6Al4V is often used in the manufacture of biomedical equipment due to its excellent properties such as light weight, high strength and good corrosion resistance in the physiological environment. Therefore, it is very important to form a non-toxic antibacterial surface on Ti6Al4V material. In this paper, a micro-nano manufacturing method of Ti6Al4V antibacterial surface was studied. In this process, the surface was firstly cut by low speed wire electrical discharge machine, and then the cut surface was hydrothermal treated. The antibacterial surface prepared by this process had the characteristics of non-toxic, stable structure, and would not cause bacteria to develop drug resistance. The preparation process is simple, friendly to the environment, and can realize mass production. The influence of different cutting times on the antibacterial surface morphology in the low speed wire electrical discharge machining was studied. The micron-grade surface obtained after three cutting times was of good quality, less molten material and high wear resistance. The influence of two etching agents mixed with different molar ratios on the micro-nano structure of antibacterial surface during hydrothermal treatment was analyzed. When the molar ratio of A and B solution was 14:1, the surface structure of the best size was obtained, and the wear resistance of the micro-nano structure surface was improved compared with the polished surface. The antimicrobial test results show that the surface of the prepared workpiece had obvious antimicrobial properties compared with the surface of the polished part after cultured for 24 h. The bacteriostatic rate of Escherichia coli was 49.55%. Based on the above, the research results of this paper have positive significance for the development of micro-nano antibacterial surface.

In this work, the reaction films were generated on the Ti–6Al–4V alloy by means of high-speed wire electrical discharge machining (WEDM-HS) technology in order to improve its microhardness and corrosion resistance. The microhardness was evaluated by using a nanoindentation tester. The corrosion behaviour was studied using measurements of potentiodynamic polarisation and electrochemical impedance spectroscopy. The experimental results showed that the processed alloys presented a higher microhardness than the matrix, and the thicker film on the surface had a greater microhardness. Additionally, the corrosion resistances of the processed alloys were superior, which could have been due to the lower corrosion current densities and the higher impedance values. Furthermore, the corrosion current densities of the processed alloys would decrease with thicker reaction films. This research provides important insights into the surface modification of titanium alloys.

Herein, we report for the first time the use of ethanol for the switchable underwater wettability on a rough titanium dioxide (TiO2) surface. The rough TiO2 thin films on the titanium surfaces are fabricated by the high speed wire electrical discharge machining (HS-WEDM) processes, and the resultant surfaces show the switch between underwater superhydrophobicity and oleophobicity via ethanol immersion and dark storage. The underlying mechanism of the switch is depicted, and the result shows that during the ethanol immersion and dark storage, the change of hydroxyl groups leads to the switch. Considering that the use of ethanol is time-saving and low-cost, we anticipate that the use of ethanol will open up a new way of surface wettability change.

The hard and brittle nature of Zirconium-based metallic glass (Zr41.2Ti13.8Cu12.5Ni10Be22.5) makes it difficult to meet industrial requirements in mechanical processing. Therefore, the processing performance of WEDM of MG was studied by using the advantages of WEDM to process hard and brittle conductive materials in this paper. The effects of peak current, pulse width and voltage on material removal rate (MRR) and surface roughness (Ra) were investigated by orthogonal experiment. Analysis of variance was employed to analyze the experimental results and obtain the optimal combination of parameters. In addition, machined surface topography was analyzed. The results show that the degree of influence of each process parameter on MRR from high to low is peak current, pulse width and voltage; and the degree of influence on Ra from high to low is pulse width, peak current and voltage. MRR and Ra are proportional to peak current and pulse width. Interestingly, the MRR and Ra do not increase with increasing voltage, but tend to increase first and then decrease. There are craters, microspheres, hard convex edges, droplets and surface microcracks on the surface of the machined workpiece. This study provides a theoretical reference for promoting the research on WEDM of MG.

In this work, a method for the fabrication of two- and three-dimensional curved surfaces with robust underwater superoleophobicity is reported for the first time on light alloys (including 5083 Al and TC4 Ti alloys) through the high speed wire electrical discharge machining (HS-WEDM). The surface morphology and compositions were characterized by scanning electron microscope and energy-dispersive X-ray spectrometer. The results showed that rough structures and a layer of oxidization were created on the light alloys by HS-WEDM cutting. The two- and three-dimensional structured curved surfaces after an ethanol immersion exhibited the extreme underwater superoleophobic property with the high oil contact angle and low oil sliding angle. More importantly, the underwater superoleophobic surfaces with the three-dimensional curved features could have many new applications. In order to use the potential functions, the durability of the fabricated samples was tested and the results showed that the samples still exhibited the underwater superoleophobic property after the underwater storage and physical mechanism tests. Additionally, this method is versatile, simple, environment-friendly, and cost-effective.

In this paper, SiCp/2024Al composites was drilled by electrical discharge machining (EDM) to investigate the effect of different electrode cross-section shapes on material removal rate (MRR). The material removal mechanism (MRM) at different discharge energy were also analyzed by changing the electrical parameters. It is found that the MRR of EDM with tube electrode is 5 times greater than that of with cylinder electrode. Electro-erosion debris filled in the discharge gap makes the tool electrode retreat frequently, greatly reducing the MRR. The MRM includes thermal spalling, melting/vaporization and oxidation. The MRM varies with different discharge energy. Thermal spalling is the main MRM at low discharge energy, while melting/evaporation occupies a dominant position in MRM at high discharge energy. Either low or high discharge energy, oxidation always occurs.

In this paper, the new alloy material, zirconium-based bulk metallic glass (Zr41.2Ti13.8Cu12.5Ni10Be22.5), which is hard and brittle, was the research object. Since the process of wire-electrical discharge machining offers the advantage of processing hard and brittle conductive materials, the effects of discharge parameters on material removal rate, surface roughness, surface morphology, carbonization and crystallization have been studied by changing discharge voltage, peak current and pulse width. The results showed that material removal rate and surface roughness increased with the increase of peak current and pulse width. Compared to peak current and pulse width, voltage exerted a less influence on material removal rate and surface roughness. The surface of the workpiece after processing presented fish-scale structure with some bumps, microspheres and droplets. As the discharge energy increased, more carbon deposits from cutting fluid were deposited on the surface of the workpiece, resulting in an increase of the carbon content which accelerated surface carbonization. The workpiece processed by low discharge energy kept a good amorphous state, but its surface layer had a tendency to crystallize. Furthermore, with the increase of discharge energy, sharp diffraction peaks began to appear, and crystallization occurred. Based on the current inadequacy of research on wire-electrical discharge machining of zirconium-based metallic glass, the purpose of this study is to provide a reference for further research on wire-electrical discharge machining of zirconium-based metallic glass.

The submillimeter-scale structures were fabricated by the high speed wire electrical discharge machining (HS-WEDM) technology on the 5083 aluminum (Al) alloy substrates. The results showed that the V-shaped groove arrays with a hierarchical structure presented the good superamphiphobicity after a solution immersion, in which the contact angles (CAs) achieved 154.70°, 154.55°, and 153.92° for water, glycerol, and ethylene glycol being, respectively. The effect of the sizes of V-shaped groove on wettability was discussed, this result may be useful for the design of controllable surfaces. In addition, a functional surface with the obvious anisotropic (the directions of the parallel and perpendicular for the grooves) sliding property revealed for water/oil may be expected to obtain potential applications in droplet-directional transportation, fluidic control, and so on. After peeling and mechanical tests the Al surfaces still exhibit superamphiphobic properties. Furthermore, the HS-WEDM technique is efficient and large area three-dimensional for building rough surface. Hence, it can be potentially suitable for industrial production of durable superamphiphobic Al surfaces with anisotropic sliding.

Inspired by the anisotropy of the rice leaf surface, high-speed wire electrical discharge machining (HS-WEDM) technology was used to build submillimetre-scale structures on the 304 stainless steel surfaces, and fluorination treatment was applied on the resulting surfaces. The wettability and microstructure of the resulting surfaces were investigated by a large depth 3D scanner, scanning electron microscopy and by the contact angle measuring instrument. The durability of the fabricated surface was evaluated by wear tests. Results show that the V-shaped groove arrays with a hierarchical structure on the processed surfaces are built by HS-WEDM. After the fluorination treatment, the as-machined surfaces show good one-direction superhydrophobicity and the obvious two-direction (the parallel and perpendicular groove directions) anisotropic wettability. The effect of the size of the V-shaped groove on the two-direction anisotropy is discussed. The wear tests show that the one-direction superhydrophobicity and the two-direction anisotropic sliding properties of the stainless steel surfaces are still exhibited after the tests. Fabricating rough surfaces by HS-WEDM is efficient and does not require complex process operation and large area three-dimensional features. This method can realise industrial production.

In this study, superamphiphobic (SAP) aluminum (Al) alloy 5083 surfaces were produced with water/oil high contact angle (CA) greater than 150° and low sliding angle (SA). A simple and environmentally friendly technology of the high speed wire electrical discharge machining (HS-WEDM) was used to introduce submillimeter-, micro- and nano-scale structures, respectively, which resulted in a hierarchical morphology. Surface energy was reduced by coating with 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) on the structured surfaces. The CAs approaching 154.80° for water, 154.55° for glycerol, and 153.92° for ethylene glycol were obtained after building hierarchical structures by HS-WEDM. The fundamental wettability models were used to explain the experimental results. The effect of the droplet size on the wettability of surfaces was also investigated. In addition, the SAP property of the Al surfaces is still exhibited after the stability, immersion, finger pressure and ultrasonic cleaning tests. SAP Al surfaces could see many wide potential applications including self-cleaning, anti-corrosion, anti-fouling, anti-icing and oil transportation.

In order to investigate the influence of the recast layer obtained by wire electrical discharge machining (WEDM) for 7075 aluminum alloy on the mechanical physical properties of the workpiece, we carried out research on the geometry parameters, microstructure, adhesion, wear resistance and corrosion resistance of the recast layer. The results show that the unit thermal power density decreases, the surface roughness Ra value increases, and the amount of the electric erosion craters and the micro/nano pits decrease with the increase of current and voltage. In the meantime, the thickness and hardness of the recast layer are increased, so the wear resistance and corrosion resistance are significantly improved. In addition, the surface hardness plays a major role in increasing wear resistance.

To improve the hydrophobic properties of the metal substrate and the using range, wire cut electrical discharge machining(WEDM) processes aluminum alloy 6061 plane twice in this paper. Under electrical discharge machining for the first time in the processing parameters of the pulse width 12μs, pulse interval 84μs, without the low surface energy materials, the static contact angles improve from 76.5°on the smooth aluminum alloy plane to 112.5°, reaching the hydrophobic state. On the basis of the processing, WEDM under 10 groups of different machining parameters processes the aluminum alloy plane for the second time, the static contact angel of up to 153.1°, achieving super-hydrophobic state. The aluminum alloy surfaces processed have micron grade similar pit craters with nanoscale structures under scanning electron microscopy(SEM). This kind of micro-nano structures make the aluminum alloy surface have the hydrophobic and super-hydrophobic properties.