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High-quality micro-holes play an important role in modern industry. However, in micro-hole drilling, a series of problems, such as chip removal and heat dissipation, restrict the improvement of micro-hole processing quality. Ultrasonic-assisted drilling (UAD) is a hybrid machining technology that combines conventional drilling (CD) with ultrasonic-assisted machining and it has great advantages when processing regular-size holes. This study mainly focuses on the influence of vibration amplitude in UAD on micro-holes manufacturing. By analyzing the cutting mode caused by periodic vibration in UAD, the influence of amplitude on the contact characteristics of the cutting edge and workpiece was studied regarding chip formation and separation ratio. Finite element simulations and experiments of micro-hole manufacturing using UAD and CD are conducted. The results show that the chip damage in UAD is more severe than CD, and as the amplitude increases, the chips became more fragmented. Compared with CD, in UAD, the thrust force is reduced by 20.1–30.05%. In addition, in UAD, the tool wear is better suppressed than in CD, and the increase in the amplitude ensures the integrity of the cutting edge. In CD, the morphology of the inner wall of the micro-hole is observed, indicating that the surface tearing and material loss are serious. In contrast, in UAD, as the amplitude increases, the material loss is almost completely suppressed. Consequently, the ultrasonic-assisted micro-hole drilling technology can be an optimal method to overcome the urgent problem of high-quality micro-hole manufacturing.

Thanks to its excellent mechanical properties, magnesium alloys have many potential applications in the aerospace and other fields. However, failure to adequately solve corrosion problems of magnesium alloy becomes one of the factors restricting its wide use in many industrial fields. Inspired by nature, researchers designed and fabricated bio-inspired water-repellent (superhydrophobic and slippery liquid-infused porous surface) surfaces with special wetting properties by exploring the surface microstructures of plants and animals such as lotus leaf and nepenthes pitcher, exhibiting excellent corrosion-resistant performance. This article summarizes the research progress on corrosion resistance of magnesium alloys with bio-inspired water-repellent properties in recent years. It mainly introduces the corrosion reasons, types of corrosion of magnesium alloys, and the preparation of magnesium alloys with bio-inspired water-repellent properties to improve corrosion resistance. In particular, it is widely used and effective to construct water-repellent and anti-corrosion coating on the surface of magnesium alloy by surface treatment. It is hoped that the research in this review can broaden the application range of magnesium alloys and provide a powerful reference for the future research on corrosion resistance of magnesium alloys.

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.

Design and fabrication of smart materials with reversible wettability for oil-water separation have attracted worldwide attention due to the increasingly serious water pollution problem. In this study, a rough oxide coating with micro/nanoscale structures is developed on the 304 stainless steel mesh (SSM) by laser ablation. The smart surface with ethanol immersion and natural drying treatments shows the wetting conversion between underwater superoleophobicity and superhydrophobicity. Based on the wettability transition behavior, both light and heavy oil-water mixtures can be separated with the high separation efficiency. Moreover, after being exposed to various corrosive solutions and high temperatures, the smart surface still shows prominent environmental stability. Switchable surface with excellent properties should be an optimal choice to solve the environmental conditions that need to be addressed urgently.

An experimental study was conducted on laser-assisted machining of β21s titanium alloy to investigate the effects of input variables of laser-assisted micromachining (LAMM) and conventional micromachining (CM) on the surface quality of β21s titanium alloy. At the same time, the tool wear patterns of LAMM and CM were revealed, and the wear law of the tools under different laser parameters when cutting different distances was studied as well. The experimental results showed that an optimum roughness value of 0.132 μm was obtained at a laser power of 30 W, a cutting speed of 100 mm/s, and a cutting depth of 10 μm, reduced by 61.7% as compared to CM. On the other hand, during the LAMM and CM experiments, the flank wear of the tools was characterized by bonding wear, while the degree of tool wear was effectively reduced in LAMM. Meanwhile, the influence of cutting length and laser power on tool wear is obtained under the condition of constant cutting speed and cutting depth. In addition, in the process of LAMM, as the cutting length increases and other processing parameters remain unchanged, the optimal laser power is not constant. Increasing the laser power appropriately can effectively suppress tool wear.

Presented in 1996, maskless localized electrochemical deposition (LECD) is an emerging and unconventional manufacturing technology that originated from precision electroforming and electroplating. As a novel additive manufacturing technology, it forms a three-dimensional structure layer by layer at atomic scale. In this work, we present a review of the theoretical basis and key parameters of maskless LECD technology. LECD process, almost limited to linear structure-based depositions, is capable of creating structures with high aspect ratio up to 280. However, the degree of deposition accuracy is not satisfactory during the whole process. Besides, the deposition rate is rather slow and the highest deposition rate of 25 μm/s was reported in published literature. Moreover, not all metals can be deposited due to the limitations of the electrochemical discipline. For instance, the effects of interelectrode potential difference, interelectrode gap, scanning speed, electrolyte concentration, and energy field on the quality of maskless LECD were discussed. Although all parameters abovementioned have an effect on the deposition results, there is currently no optimization software that can calculate the optimal values in an effective manner. By combining different deposition structures, special tiny part systems can be generated or integrated into devices for tackling current and future challenges in some fields such as electronic circuits, microfluidics, communications, and biomedical aspect. Additionally, this work also introduces main hybrid variants of LECD. Possible future efforts to fully exploit LECD potential are also discussed.

Metals are indispensable engineered materials for day-to-day life. Researches focused on metallic surfaces with superlyophobicity (superhydrophobicity, superoleophobicity, underwater superoleophobicity and slippery characteristic) have attracted much attention recently. Nature is a magician that gives each organic life a unique advantage. Researchers have created a large number of biomimetic superlyophobic metallic surfaces through various approaches. These biomimetic superlyophobic metallic surfaces exhibit advantages in many applications, such as self-cleaning, corrosion resistance, anti-icing, and drag reduction. In this review, the specific fabrication and applications of biomimetic superlyophobic metallic surfaces were reported. The remaining challenges and future outlook of biomimetic superlyophobic metallic surfaces were preliminarily analyzed. It is hoped that the review will be essential for broadening the scope of potential applications of metals and providing a powerful reference for future research on metal-based advanced functional materials.

Magnesium alloys have been widely used in many fields such as the automobile industry, electronics industry, aerospace and optical equipment based on their excellent mechanical properties. However, the extremely poor corrosion resistance of magnesium alloys severely restricts its application and development in many fields. A superhydrophobic coating is prepared on the surface of magnesium alloy through laser processing technology and fluorination treatment. The modified laser processing surface has excellent superhydrophobic properties, making it difficult for corrosive media to contact the surface, and effectively improving the corrosion resistance of the surface. The corrosion resistance provided by superhydrophobic surfaces has been evaluated by electrochemical tests. The results show that, compared with bare surfaces and laser-textured surfaces, superhydrophobic surfaces have better corrosion resistance, which is of great significance for expanding the potential applications of magnesium alloys.

Antireflection functional surface has important applications in photoelectric detection, artificial blackbody, infrared imaging and other fields. In this study, the titanium alloy surface with high absorptivity was fabricated by nanosecond laser system. The effects of different scanning filling intervals on microstructure morphology and reflectance were studied. With the decrease of scanning interval, there are more and more micro clusters and micro holes on the surface, and the reflectance decreases gradually. When the scanning filling interval was reduced to 0.01 mm, the reflectance of titanium alloy surface could be decreased by 3% in the wavelength range of 400–1000 nm after laser treatment. In addition, in order to obtain a composite functional surface with superhydrophobic properties, the laser-processed surface was modified with a mixed solution of $1 H,\ 1 H,\ 2 H,\ 2 H$ -perfluorodecyltriethoxysilane and methanol. The maximum contact angle is 153.8° when the laser filling interval was 0.01 mm. It provides a reference for the preparation of antireflection and superhydrophobic composite functions surface.

As two typical special wettability materials, superhydrophobic and superoleophobic surfaces are the most widely studied interfaces because of their excellent water-or oil-repellent ability. However, how to use a simple strategy to obtain those surfaces is still a huge challenge. On the other hand, corrosion tend to occur while using metallic materials, resulting in poor performance of metallic equipment and even serious safety hazards. In this work, a one-step strategy of nanosecond laser ablation was presented to construct the microstructures acquired by superhydrophobic and superoleophobic aluminum alloy surfaces. The superhydrophobic and superoleophobic properties of microstructured surfaces were obtained via high temperature and fluorosilane treatments on laser-processed surfaces, respectively, and the oil-repellent and corrosion resistance properties of both substrates were studied. The potentiodynamic polarization test shows that the superoleophobic surface had a better corrosion resistance than the superhydrophobic surface, which will provide an effective protection for the bare aluminum alloy. Meanwhile, the superoleophobic surface had good chemical stability. It is believed that the nanosecond laser technology can offer an effective strategy for constructing the microstructures acquired by large-area superhydrophobic and superoleophobic surfaces on aluminum alloy materials.

As two typical aspects of the wettability based on bio-inspired functional surfaces, superhydrophobic and anisotropic wetting properties have attracted much interest in practical applications. However, how to use a simple approach to realize those properties is still a huge challenge; simultaneously, the corrosion resistance is also important when the surfaces are introduced into more complex environments. In this paper, a simple and highly effective two-step approach for the fabrication of bio-inspired superhydrophobic and anisotropic wetting surfaces is reported. Aluminum alloy (Al) plates were first structured using nanosecond laser, and then were placed in an oven for low-temperature annealing (100 °C). The results show that the nanosecond laser ablation not only builds dual- and three-level structures inspired by lotus leaf and rice leaf but also oxidizes the Al materials, resulting in an oxide film covering on the surface. After the low-temperature annealing, the as-fabricated surfaces display the superhydrophobic and anisotropic wetting properties by adjusting the scan spacing of adjacent microgrooves. The potentiodynamic polarization and electrochemical impedance spectroscopy tests show that the as-fabricated surfaces have excellent corrosion resistance that can provide an effective protection for the Al materials. In addition, this approach can be applied to a broad range of metals (stainless steel, copper and titanium). This research will be instructive for the applications of functional materials with the properties of superhydrophobicity and anisotropic wetting.

This research studied the surface homogenization and morphology of a Ti-6Al-4V alloy using the longitudinal-torsional coupled ultrasonic vibration-assisted milling (UVAM) of a ball-end cutter, in which a method of continuous processing between the flat surface and the freeform surface connection was proposed. The cutting experiments compared the UVAM method with the conventional milling (CM) process by setting three parameters: the cutting speed, feeding rate, and depth of cut. The finished surface roughness, the in situ cutting force, and the topography of the surface are characterized in this paper. The surface roughness that resulted from UVAM ball-end milling was much better than the surface roughness of CM at high cutting speeds. In particular, there was a steep decrease of the average roughness rate from 0.668 μm at 4000 rpm to 0.161 μm at 5000 rpm. Moreover, the mean cutting force in ball-end milling using UVAM decreased by 20–40% compared to the CM process. The homogenization of the surface roughness also improved from 59.4 to 15.1% in the UVAM method compared to the CM method when the transverse-longitudinal ratio was taken into consideration. The cutting experiments have not only powerfully demonstrated the validity of the UVAM method but have also shown the beneficial effect that the UVAM process brings.

GH4169 superalloy has excellent properties such as high strength, high hardness and high temperature resistance, and is widely used in aerospace, automobile manufacturing, defense industry and biomedical fields. In the cutting process of superalloy, there are some problems such as serious tool wear and poor surface quality. The placement of micro-pit arrays on the rake face of cemented carbide tools can effectively improve the friction and wear resistance of the tools and improve the cutting conditions. In this article, ABAQUS software is used to simulate the micro-pit array tool orthogonal micro-cutting GH4169 superalloy. The cutting simulation of GH4169 superalloy was carried out by using micro-pit diameters of 35 μm, 30 μm, 25 μm, 20 μm and non-texture, respectively. The cutting-chip contact state, cutting force, cutting temperature and chip shape during the cutting process were analyzed. The study found that the placement of micro-pit texture can effectively reduce the cutting force during cutting and improve chip breaking. The micro-pit texture can intercept debris and hard particles on the bottom surface of the chip, reducing scratches on the rake face of the tool and the furrow effect of the hard particles, effectively improving the wear resistance of the tool.

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.

In this work, the localized electrochemical micro additive manufacturing technology based on the FluidFM (fluidic force microscope) has been introduced to fabricate micro three-dimensional overhang metal structures at sub-micron resolution. It breaks through the localized deposition previously achieved by micro-anode precision movement, and the micro-injection of the electrolyte is achieved in a stable electric field distribution. The structure of electrochemical facilities has been designed and optimized. More importantly, the local electrochemical deposition process has been analyzed with positive source diffusion, and the mathematical modeling has been revealed in the particle conversion process. A mathematical model is proposed for the species flux under the action of pulsed pressure in an innovatively localized liquid feeding process. Besides, the linear structure, bulk structure, complex structure, and large-area structure of the additive manufacturing are analyzed separately. The experimental diameter of the deposited cylinder structure is linearly fitted. The aspect ratio of the structure is greater than 20, the surface roughness value is between 0.1&ndash, 0.2 &mu, m at the surface of bulk structures, and the abilities are verified for deposition of overhang, hollow complex structures. Moreover, this work verifies the feasibility of 3D overhang array submicron structure additive manufacturing, with the application of pulsed pressure. Furthermore, this technology opens new avenues for the direct fabrication of nano circuit interconnection, tiny sensors, and micro antennas.

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.

Despite the success of previous methods for fabricating underwater superoleophobic surfaces, most of the surfaces based on soft materials are prone to collapse and deformation due to their mechanically fragile nature, and they fail to perform their designed functions after the surface materials are damaged in water. In this work, the nanosecond laser-induced oxide coatings on hydrophilic bulk metals are reported which overcomes the limitation and shows the robust underwater superoleophobicity to a mechanical challenge encountered by surfaces deployed in water environment. The results show that the surface materials have the advantage that the underwater superoleophobicity is still preserved after the surfaces are scratched by knife or sandpaper and even completely destroyed because of the hydrophilic property of damaged materials in water. It is important that the results provide a guide for the design of durable underwater superoleophobic surfaces, and the development of superoleophobic materials in many potential applications such as the oil-repellent and the oil/water separation. Additionally, the nanosecond laser technology is simple, cost-effective and suitable for the large-area and mass fabrication of mechanically durable underwater superoleophobic metal materials.

The fabrication of pure copper microstructures with submicron resolution has found a host of applications, such as 5G communications and highly sensitive detection. The tiny and complex features of these structures can enhance device performance during high-frequency operation. However, manufacturing pure copper microstructures remain challenging. In this paper, we present localized electrochemical deposition micro additive manufacturing (LECD-μAM). This method combines localized electrochemical deposition (LECD) and closed-loop control of atomic force servo technology, which can effectively print helical springs and hollow tubes. We further demonstrate an overall model based on pulsed microfluidics from a hollow cantilever LECD process and closed-loop control of an atomic force servo. The printing state of the micro-helical springs can be assessed by simultaneously detecting the Z-axis displacement and the deflection of the atomic force probe cantilever. The results showed that it took 361 s to print a helical spring with a wire length of 320.11 μm at a deposition rate of 0.887 μm s−1, which can be changed on the fly by simply tuning the extrusion pressure and the applied voltage. Moreover, the in situ nanoindenter was used to measure the compressive mechanical properties of the helical spring. The shear modulus of the helical spring material was about 60.8 GPa, much higher than that of bulk copper (∼44.2 GPa). Additionally, the microscopic morphology and chemical composition of the spring were characterized. These results delineate a new way of fabricating terahertz transmitter components and micro-helical antennas with LECD-μAM technology.

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 surface of the titanium alloy was blackened by a nanosecond pulsed laser, and two-dimensional and three-dimensional morphology observations and microstructure reflection measurements were performed by scanning electron microscopy (SEM), laser confocal scanning microscopy (LCSM) and microscopic angular resolution spectrometry (ARM). The effect of laser processing depth on reflectivity was studied by one-way filling scanning method. The results show that under different laser processing times, different microstructures are formed, and as the number of laser processing increases, the reflectivity of light decreases. In the 400–1000 nm band, the reflectance of the sample can be reduced to a minimum of about 1%.

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 view of high coefficient of friction and poor wear resistance of titanium alloy, laser processing method is used to form grooves on the surface of titanium alloy, and the grooves surface of titanium alloy is coated with titanium dioxide films to improve the wear resistance of titanium alloy. Friction tests were carried out on three surfaces of titanium alloy respectively in this paper: smooth surface, groove surface, groove surface coated with titanium dioxide films. A comparative analysis of wear depth and morphology different test conditions were conducted accordingly. The experimental results show that titanium alloy groove surface coated with films has the lowest coefficient of friction, produces the shallowest scratch depth and the least wear, Titanium alloy grooves surface coated with films, however, is very slightly different from titanium alloy grooves surface. In addition, titanium alloy grooves surface coated with films has the least increase of oxygen after wear.

Nature gives us a large number of inspirations in designing functional materials. Many plant leaves with self-cleaning properties are ubiquitous in nature. These plants have hierarchical structures, which have extreme repellency to liquids and have considerable technical potential in various applications. Herein, we present a method for fabricating bionic taro leaf surfaces by direct laser interference lithography (DLIL) and hydrothermal treatment. The micro-pillar array structure (MPA) was fabricated by DLIL, and a layer of nano-grass structure (NG) was grown on it by hydrothermal treatment. Experiments indicate that the hierarchical composite structures not only have a satisfactory superhydrophobic function with the apparent contact angle (CA) of 172° and sliding angle (SA) of 4°, but also have a strong anti-icing ability with the delay time (DT) of 3723 s. The method is simple and high-efficient for fabricating bionic self-cleaning and anti-icing surfaces.

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.

Titanium alloy has been widely used in the aerospace field due to its advantages of low density, high specific strength and high-temperature resistance. Its scope of application, however, has been narrowed down because of its high reflectivity to light. In order to maximize the potential, it becomes necessary to construct a surface light trapping structure of titanium alloy. Therefore, a simple and tunable method was introduced in this paper to fabricate antireflection microstructures on titanium alloy surface with the superhydrophobicity based on nanosecond laser. By optimizing the laser processing speed parameters, microstructured surfaces with low reflectance over the entire visible wavelength range and near-infrared region (400–1000 nm) can be obtained. Results indicate that when the scanning speed is 100 mm/s, the minimum reflectance in the 900–1000 nm wavelength range is less than 1%, and the total reflectance in the 500–1000 nm wavelength range stabilizes below 6%. In contrast, the surface of conventional titanium alloy absorbs only about 50% of the incident light, and the remaining 50% is reflected. Furthermore, treated surfaces demonstrate effective performance concerning hydrophobicity, with a maximum contact angle of 153.03°. The results show that the nanosecond laser can induce the anti-reflection and super-hydrophobic properties, and improve the absorption capacity of the surface.

This paper aims to study the surface homogenization and integrity of Ti-6Al-4V alloy by longitudinal-torsional coupled ultrasonic vibration assisted ball-end milling. A method of continuous processing between the flat surface and freeform surface connection is proposed by using ultrasonic vibration assisted ball-end precision milling, during this process, it is not necessary to exchange the cutting tool. The way has been explored for changing the homogenization of surface on Ti-6Al-4V by ultrasonic vibration-assisted milling (UVAM). Cutting experiments employing three parameters, cutting speed, feed rate and depth of cut and two types of machining forms using ball-end milling with UVAM and conventional milling (CM) respectively. The high frequency cutting force, finished surface roughness, topography and residual stresses on the surface and tool wear have been measured by advanced instruments. Particularly, adopting the high frequency cutting force measurement system, it is concluded cutting force in ball-end milling decreased significantly using UVAM as against CM. Moreover, the surface roughness by UVAM with ball-end milling is much better than the CM at a high cutting speed. However, an opposite trend is observed at a low cutting speed. Especially, there is a steep decrease from Ra 0.828 μm average value at 4000 rpm to Ra 0.129 μm average value at 5000 rpm. At the same time, the homogenization of surface roughness and residual stresses decrease significantly in UVAM as compared to which in CM when taking the transversal-longitudinal ratio into consideration. Cutting experiments and measuring results are demonstrated the validity and feasibility of UVAM with ball-end milling, and this method enjoys significant advantages compared to CM process.

This paper primarily analyzed the mechanism of crack propagation in brittle materials micro-grinding, and obtained the empirical formula of the maximum unreformed thickness. Using the grinding rods with diameters of 0.7mm and 1.0mm, the single-factor experiments were carried out, through changing spindle speed, feed speed and depth of cut. We selected different processing parameters to study the general rules that the processing parameters affect the surface quality. The results show that the grinding depth has the most obvious influence on the surface quality, and the surface quality is the best when the grinding depth is 5 μm. The feed speed affects the surface quality secondarily, and the better surface quality can be obtained at 50 mm/min. The effect of spindle speed on surface quality is not obvious, but with the increase of spindle speed, the surface quality first increases and then decreases. We compare the different processing methods in order to study the effect of different processing methods on the surface quality. It can be concluded that in the case of smaller depth of cut, micro- grinding is easier to obtain high-quality machined surface than micro-milling

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.

Materials with special wettability have drawn considerable attention especially in the practical application for the separation and recovery of the oily wastewater, whereas there still remain challenges of the high-cost materials, significant time, and complicated production equipment. Here, a simple method to fabricate the underwater superoleophobic and underoil superhydrophobic brass mesh via the nanosecond laser ablation is reported for the first time, which provided the micro-/nanoscale hierarchical structures. This mesh is superhydrophilic and superoleophilic in air but superoleophobic under water and superhydrophobic under oil. On the basis of the special wettability of the as-fabricated mesh, we demonstrate a proof of the light or heavy oil/water separation, and the excellent separation efficiencies (96%) and the superior water/oil breakthrough pressure coupled with the high water/oil flux are achieved. Moreover, the nanosecond laser technique is simple and economical, and it is advisable for the large-area and mass fabrication of the underwater superoleophobic and underoil superhydrophobic mesh in the large-scale oil/water separation.

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 paper, the milling experiments of the 7075 Aluminum alloy thin wall specimens are carried out. In the dry cutting under the experimental conditions, the hard alloy cutter the use of the 7075 Aluminum alloy milling can get better quality of the thin-walled specimens, machining, cutting and cutting edge burr and the source, the chip adhesion phenomenon, in the selection of cutting speed for variable conditions, with the increase of cutting speed, milling of thin-walled specimen deformation gradually becomes smaller the thin, the specimen surface residual stress gradually increase, in the selection of feed speed conditions within the range of variables, with the increase of feed speed, the 7075 Aluminum alloy milling of thin-walled specimens. The deformation degree increased, thin specimen surface residual stress decreases gradually, in the selection of cutting depth conditions the range of variables, with the increase of cutting depth, the 7075 Aluminum alloy test milling of thin-walled parts is the greater the degree of deformation, thin-walled specimen surface residual stress was gradually decreased, residual stress the hour gradually thin plate specimens deformation amount is small, the milling of thin-walled specimens after deformation is inevitable.

In this work, the authors propose a method to obtain micro- and nano-structures on the stainless steel mesh (SSM), which showed the potential application for the treatment of water pollution based on its hydrophobicity and oleophilicity. The textured surfaces with the micrometer scale pore array patterns on the SSM are formed by three-beam laser interference lithography. And the nanostructures, such as nanorods, nanowires, and nanoflakes, are obtained on the surfaces of the SSMs after laser irradiation by heating for 70 min at approximately 600 °C under ambient conditions. The results showed that the nanostructures can be easier to grow on the rough surface than the smooth ones. In addition, these nanostructures are also grown on the surfaces of the laser irradiated SSM with the candle soot (LISSM@C). Raman spectrum proves that the nanostructures are α-Fe2O3 and α-Fe2O3/reduced graphene oxide (rGO). The measurement of the contact angle indicates that the oil-water separation can be realized on the LISSM@C after the thermal treatment.In this work, the authors propose a method to obtain micro- and nano-structures on the stainless steel mesh (SSM), which showed the potential application for the treatment of water pollution based on its hydrophobicity and oleophilicity. The textured surfaces with the micrometer scale pore array patterns on the SSM are formed by three-beam laser interference lithography. And the nanostructures, such as nanorods, nanowires, and nanoflakes, are obtained on the surfaces of the SSMs after laser irradiation by heating for 70 min at approximately 600 °C under ambient conditions. The results showed that the nanostructures can be easier to grow on the rough surface than the smooth ones. In addition, these nanostructures are also grown on the surfaces of the laser irradiated SSM with the candle soot (LISSM@C). Raman spectrum proves that the nanostructures are α-Fe2O3 and α-Fe2O3/reduced graphene oxide (rGO). The measurement of the contact angle indicates that the oil-water separation can be realized on the LISSM@C...

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.

A simple and inexpensive one-step laser cladding method is reported to make the stainless steel mesh underwater superoleophobic. The micro/nanoscale morphologies were created via cladding a copper foil onto the stainless steel mesh using the nanosecond laser marking system. The fabricated stainless steel mesh has the underwater superoleophobic property with oil contact angles greater than 150°. Based on the special wettability, the fabricated stainless steel mesh is used to separate the light oil–water mixtures, and the separation efficiencies are >98.3%.

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.

This paper put the microstructures of rice leaf surface as bionic object, grating micro-arrays were processed on 7075 aluminum alloy surface by high speed micro-milling machining (HSMM). The micromorphologies and hydrophobic properties of specimen surfaces were studied adopting scanning electron microscopy and contact angle (CA) goniometer, and analyzing its hydrophobic mechanism. Results show that hydrophobic surfaces is successfully fabricated only by building grating micro-array structures on aluminum alloy surface using HSMM without modifying any chemical substances, the contact angle on aluminum alloy surface increased maximally to 152. 83° from 63.27° before processing. Furthermore, the contact angle on specimen surfaces appear anisotropic wettability, which the contact angle difference of two direction is about 40°∼60°. In addition, the hydrophobicity and super-hydrophobicity on aluminum alloy surface is a coupling function result by both submillimetre regular grating arrays and many irregular nanoscale pits and projections distributing on submillimetre grooves surface.

Wettability is one of the important performance measuring the hydrophobicity of metal surface. There has important relationship between microstructures and surface wettability. In this paper, square pillar microarrays with different geometrical parameters were processed on hydrophilic metal substrates by high-speed micro-milling technology, observed superficial morphologies and apparent contact angles of microstructures, and analyzed the influencing laws of geometrical parameters on surface wettability. Experimental results showed that the wetting transition from hydrophilicity state to hydrophobicity state was successfully achieved by fabricating micron-grade regular array on aluminum alloy surface, and the hydrophobic property on solid surface is a common coupling results of micronano-binary structures both microscale pillars and nanoscale pits and convexities. In this experiment, a good hydrophobic surface with larger apparent contact angle can be obtained when pillar width is 20 μm, pillar spacing is 100 μm, pillar height is 50 μm and the droplet volume is 3 μl. In addition, the water droplets on aluminum alloy surface with square pillar microarray is in a mixed state between Wenzel and Cassie-Baxter, and the surface wettability can be control by changing the geometry parameters of microstructures.

Many creature surfaces owe to the exitance of the unusual microstructures that could influence their wet ability, these microstructures also provide a new idea for fabricating function materials. In this paper, the super-hydrophobic structures were successfully built on the surface of stainless steel needle by a simple technique combining of chemical etching and molecules modification. After the etching reaction, porous microstructures were created on the stainless steel needle surface. By modifying 1H,1H,2H,2H-perfluorodecyltriethoxysilane, the stainless steel needle showed a good super-hydrophobic property with a contact angle (CA) greater than 150°. Moreover, the stainless steel needle revealed obvious faired activity in resistance test. The result shows that the faired property of the super-hydrophobic needle is better than the hydrophobic one. The as-obtained needle with both super-hydrophobic and faired properties has the potential application in modern medical devices.

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.