Laser processing technology is commonly used to create superhydrophobic surfaces due to its simplicity, efficiency, and flexibility. However, conventional laser processing inevitably leads to thermal damage that affects the material properties. Here, a novel dynamic water film assisted laser micromachining (DWFALM) technique is demonstrated as a cost-effective method to achieve texturing of titanium alloy surfaces for superhydrophobicity. Compared to pure laser processing, the thermal damage on the surfaces processed by the DWFALM technique was significantly reduced. The effects of different laser single-pulse energies and scanning spacing on the microstructure and wettability were investigated. The transition in wettability from superhydrophilic to superhydrophobic was explored. The results indicated that the contact angle stabilized at approximately 154 degrees after 43 days. Additionally, the simulation results closely matched the droplet impact process. The textured superhydrophobic Ti6Al4V surfaces produced by DWFALM have a wide range of potential applications in anti-icing, heat transfer, and droplet manipulation.

C/SiC composites have excellent mechanical properties such as high specific strength and high temperature resistance, and are widely used in aerospace fields. However, due to its special structure and material properties, the tool wear is severe when machining with conventional methods, and the processing quality is poor. The purpose of this paper is to reveal the progressive wear behavior, wear mechanism of the tool, and its effect on machining performance in conventional milling (CM) and ultrasonic vibration-assisted milling (UVM) of C/SiC composites under forward fiber cutting (FC) and reverse fiber cutting (RC). The material removal and heat transfer models were established, and the stress distribution characteristics of cutting -edge were analyzed by finite element method (FEM). Combined with the wear morphology, cutting heat, and cutting force, the tool wear behavior and mechanism in UVM and CM under FC and RC were studied, and their effects on machining quality were analyzed. The results show that there are great differences in heat transfer and removal process between FC and RC. In UVM, the introduction of ultrasonic vibration reduces the adhesion of fine chips, weakens the strong friction and scratching between the hard chips and the cutting -edge, and alleviates the tool wear. The flank wear VB and cutting -edge wear area WA in RC are larger than those in FC, the abrasive wear is intensified, the material even peeling under mechanical shock, and the adhesive wear is more serious. When the tool wear intensifies to a certain extent, the difference of the cutting process caused by mechanical anisotropy of C/SiC composites is weakened, and the surface micro-defects and surface roughness Sa change little under FC and RC. This research contributes to the realization of high-quality and low-cost processing of C/SiC composites.

The waterjet-assisted laser processing (WJALP) technology has a significant effect in reducing the damage to the workpiece caused by laser ablation. While, due to the limitation of the depth-of-field (DOF) of the microscopic magnification system, the processing quality and features of the material surface cannot be accurately identified during processing. In multi-focus image fusion (MFIF) according to different DOF images, the conventional wavelet transform in the condition of waterjet cannot accurately provide detailed features of microscopic images. In this work, in order to overcome the shortcomings of traditional wavelet transform, the method of discrete wavelet transform (DWT) based on the human vision principle (HVP) was proposed, and stretched the detail part while fully retained the source image information. Based on morphological theory and defogging algorithm, the waterjet interference was excluded by image pre-processing as much as possible. The approximate component and detailed component were obtained by DWT, and the detailed components were stretched utilizing HVP according to the brightness and darkness provided by the approximate component. Finally, the image brightness was adjusted using an adaptive gamma correction. According to the experimental results, in the case of complex flowing water films, SD , E ( F ), AG , and SF can reach 75.45%, 95.38%, 73.60%, and 77.45% of the ideal fusion, respectively, which indicated that the proposed method can achieve a better fusion effect in different waterjet situations.

Nickel-titanium shape memory alloy (NiTi-SMA) can restore its original shape after deformation, making it show great application in the fields of biomedicine, aerospace, etc. The wire electrical discharge machining (WEDM) has the advantage of machining micro and complex structures, which can greatly promote the application of NiTi-SMA. However, there are issues such as heat affected layer (HAL) on the surface of WEDM, which can affect the functionality of NiTi-SMA. Therefore, when using WEDM to NiTi-SMA, more attention should be paid to the functional changes after machining. This article primarily examine is the impact of peak current and pulse on time on the phase transformation behavior, shape memory effect, and mechanical properties of NiTi-SMA during WEDM, and introduces into the magnetic field assisted (MFA) process to improve the machining performance of NiTi-SMA. The results indicate that the HAL formed on the surface of NiTi-SMA is primarily composed of the irreversible phase transformation of B2 austenite. This layer induces a hardening effect, resulting in an increase in the phase transition temperature and a decrease in the phase transition energy (∆HM-A), as a result, the martensitic phase transformation behavior is suppressed. When the peak current and pulse on time increase, the surface quality of the NiTi-SMA processed decreases. The thickness of the HAL and microhardness increase, causing an increase in the phase transition temperature of the NiTi-SMA processed samples. Additionally, the transformation energy ∆HM-A, shape recovery rate, and mechanical properties decrease, and after recovery, more surface cracks appear and show larger extensions. MFA-WEDM can improve the surface quality of NiTi-SMA processing, reduce the thickness of the HAL, and effectively enhance the phase transformation temperature and energy ∆HM-A of the NiTi-SMA processed samples. With a magnetic field strength of 0.45T, the tensile shape recovery rates of 98%, 94.4%, and 91.0% were achieved at 2%, 5%, and 8% strain, respectively. This represents an improvement of 8.9% compared to the maximum shape recovery rate with conventional WEDM. At the same time, it also inhibits the generation and propagation of surface cracks after deformation recovery. Additionally, MFA-WEDM improves the mechanical properties of NiTi-SMA, and reduces the thickness of the brittle fracture region by 49.7% compared to conventional WEDM. Therefore, MFA-WEDM can effectively enhance the shape memory effect of NiTi-SMA. However, it is important to avoid excessive peak currents and pulse on time to achieve optimal shape memory functionality.

Smart microstructured surfaces have attracted extensive attention in recent years, because the surface microstructure morphology can be tuned using an external field to change the wettability. Inspired by the surface microstructures of butterfly wings, a tilted array microstructure was fabricated on the surface of NiTi shape memory alloy (NiTi-SMA) using wire electrical discharge machining (WEDM). The modified surface with fluorosilane showed superhydrophobicity and anisotropic droplet sliding. As the shape of the tilted microarray structure could be repeatedly switched between the original shape and deformation under the action of force and heat, the contact angle of the surface was repeatedly switched between 155.9 degrees +/- 0.2 degrees and 150.3 degrees +/- 0.3 degrees , and the anisotropic sliding angle of the surface was repeatedly switched between 7.9 degrees +/- 1.6 degrees and 22.9 degrees +/- 1.3 degrees , and 19.6 degrees +/- 0.6 degrees and 53.4 degrees +/- 2.9 degrees. The range of switchable anisotropic sliding could be adjusted by changing the microstructure spacing L. In addition, the surface of the tilted microarray structure showed a directional water transport ability under the action of vibrations, and the directional transmission of water droplets could be selectively controlled by changing the morphology of the surface microstructure. Therefore, a smart surface with switchable wettability was realized on the NiTi-SMA surface, providing a new method to realize the smart control of droplets on smart microstructured surfaces.

With the increasing problem of water pollution, oil-water separation technology has attracted widespread attention worldwide. In this study, we proposed laser electrochemical deposition hybrid preparation of an oil-water separation mesh and introduced a back-propagation (BP) neural network model to realize the regulation of metal filter mesh. Among them, the coating coverage and electrochemical deposition quality were improved by laser electrochemical deposition composite processing. Based on the BP neural network model, the pore size after electrochemical deposition could be obtained only by inputting the processing parameters into the model, enabling the prediction and control of the pore size of the processed stainless-steel mesh (SSM), and the maximum residual difference between the predicted value and the experimental value was 1.5%. According to the oil-water separation theory and practical requirements, the corresponding electrochemical deposition potential and electrochemical deposition time were determined by the BP neural network model, which reduced the cost and time loss. In addition, the prepared SSM was found to achieve efficient separation of oil and water mixtures, reaching 99.9% separation efficiency in a combination with oil-water separation, along with other performance tests without chemical modification. The prepared SSM showed good mechanical durability and the separation efficiency exceeded 95% after sandpaper abrasion, thus, still maintaining the separation ability of oil-water mixture. Compared to other similar preparation methods, the method proposed in this study has the advantages of controllable pore size, simplicity, convenience, environmental friendliness, and durable wear resistance, offering important application potential in the treatment of oily wastewater.

Waterjet-assisted laser direct inscription (WJALDI) technology has presented a positive effect to alleviate the thermal damage in workpieces caused by laser ablation. This research pays attention to the effect of aqueous media on the microstructure evolution and phase composition of materials during laser ablation, and few relevant researches have been reported. In this work, titanium alloy (TC11) was applied to fabricate microgrooves utilizing WJALDI and laser direct inscription in the air (LDI). The interaction effects between the laser, water, and the material within a complete ablation cycle were analyzed in depth. The geometry and thermal damage region were observed and discussed to prove the machining performance. The microstructure evolution that happened on and underneath the microgroove surface was also studied. The results revealed that the effect of cooling and impacting significantly reduced the accumulation of debris and molten metal, and better processing quality was obtained in WJALDI. According to the analysis of electron backscattered diffraction (EBSD), the grain refinement of the inner material was alleviated, low-angle grain boundaries with the features of uniform distribution were generated, and the adjacent grains of α phase have small kernel average misorientation. In addition, compared with LDI, WJALDI offered a wide microgroove with a small size of heat affected zone (HAZ) and thin thickness of the recast layer, while less depth. Therefore, the developed technology in this work could be a promising approach for the micromachining of titanium alloy or even other difficult-to-cut materials with high quality.

Objective Waterjet- assisted laser processing technology provides a new direction in the development of laser processing that can effectively mitigate thermal damage to materials during laser processing; thus, it has good prospect for microfabrication applications. During processing, the quality of the material surface can be inspected in real time, and the introduction of microscopic systems can provide a more convenient observation of material processing details as well as improve the corresponding efficiency. However, because of the interference of the waterjet, bubbles are present in the source image captured by the CCD camera, obscuring detailed information and blurring the surface. In addition, the source image sequence is only partially focused because of the limited depth- of-field of the microscope system. To enhance the detail of surface features of materials for the purpose of dehazing, an image processing technique is employed to improve the contrast of an image by emphasizing the respective brightness, saturation, and textural features of local areas. However, conventional dehazing algorithms begin with the image itself. Without considering that the local area processing method has problems including loss of detailed information and excessive contrast enhancement, development of an image dehazing method for the local areas of different images is necessary. In the traditional microscope mode, the effect of extending the depth-of- field can be achieved via component deformation; however, this has reduced efficiency, large equipment size, and low lateral resolution. Currently, image fusion based on the transform domain is a popular research topic, and is one of the most widely used and mature methods in practical applications. Methods This study solves the problems of waterjet interference and image fusion. Bubbles were maximally reduced via foreground segmentation and morphological theory, and the detailed information of the source images was enhanced according to the adaptive multiscale Retinex dehazing algorithm. After dividing the image into blocks, the detail index is defined by the standard deviation value of each block. The most suitable Gaussian filter function scale value was determined, and the corresponding weights were calculated to linearly superimpose the single-scale Retinex algorithm of different scales. The source image was decomposed into detail and approximate components using discrete wavelet transform, the detail component was stretched according to the human vision principle, and each discrete wavelet inverse transform was performed according to the fusion rules. As a result, a full- focus image with an extended depth-of- field can be realized. Results and Discussions The experimental system adopted in this work was set up as depicted in Fig. 1, mainly constituting a laser processing and image capture system, and a high-pressure waterjet assist system. The processing and image capture system comprises a laser, waterjet nozzle, and CCD camera. The processed material surface images of the waterjet interference problem are presented in Fig. 5: ( a) displays one of the source images captured in the waterjet environment and ( b) shows the final processed image. The interference of bubbles on the image information in the processed image appears to fade, and more detailed features are restored. Compared with the source image, the average gradient (AG), standard deviation ( SD), and spatial frequency ( SF) of the processed image improved by 27.6%, 20.1%, and 4.74%, respectively. Table 3 presents the image quality comparison results of the three source images in the air and waterjet environments. In the waterjet environment, the image quality was significantly lower than that in the air environment, where the SF and AG were reduced by 33.88% and 31.11%, respectively. Figure 6 shows the source images of the material surface collected for waterjet nozzle diameters of 0.4, 0.8, and 1.2 mm as well as the processed images after algorithmic processing. As the diameter of the waterjet nozzle increases, the thicker the flowing water layer on the surface of the sample, and the more limited the image information that can be obtained from the source image. According to Fig. 7(b), the three indicators of the processed image obtained with the diameter nozzle of 0.4 mm reached 95.41%, 71.88%, and 67.29%, respectively. Fig. 8 displays the source images of the material surface collected for waterjet inclination angles of 30 degrees, 45 degrees, and 60 degrees, besides the processed images after algorithmic processing. As the waterjet inclination angle decreases, the thicker the flowing water layer on the surface of the sample, the more limited the image information that can be obtained from the source image. As shown in Fig. 9(b), the three indicators of the processed image considering the 45 degrees angle reached 90.59%, 72.69%, and 94.50%, respectively; thus, maximizing the exclusion of the interference of the waterjet, which could restore part of the detailed features. Conclusions In waterjet-assisted laser processing, microscopic images of material surfaces are subject to waterjet interference and depth-of- field limitations. Therefore, we propose a waterjet laser processing image-fusion algorithm based on the Retinex dehazing algorithm. The method determines different Gaussian filter function scales for various images, improves the dehazing effect of traditional algorithms, and stretches the detailed components according to human vision. As a result, detail of source image information was enhanced and the image quality was improved. Experiments demonstrate that the algorithm reduces the interference of the waterjet in the source image, enhances the detailed information of the image, and achieves full focus. As the diameter of the waterjet nozzle increases and the inclination angle decreases, the water film on the surface of the material becomes thicker, and the quality of the source image is subsequently reduced, which is difficult for the algorithm to process. However, the experimental results show that with the nozzle diameter of 1.2 mm or an inclination angle of 30 degrees, the processed image still presents most of the detailed features and improved image quality. Thus, the developed algorithm can effectively improve the efficiency of waterjet-assisted laser processing and is expected to be widely used in liquid- assisted laser processing.

The material is removed by thermal effect by wire electrical discharge machining (WEDM) and a thermal damage layer is formed on the machined surface, which affects the function and performance of NiTi shape memory alloys (NiTiSMAs). However, the material removal process and thermal damage of WEDM are not clear. Therefore, by establishing the empirical formula of discharge channel radius, and based on the theory of heat transfer field and fluid mechanics, the finite element mode of crater morphology evolution and material removal process of WEDM is established in this paper. The results show that the reaction force of the vaporized metal and the gradient of surface tension caused by temperature are the fundamental reasons for driving the molten flow in the pit to both sides and forming bulges. The spatter of molten material is caused by the reaction force of metal vapor greater than the surface tension. When the material absorbs and transfers heat at a rate close to the same level during removal, a steady state effect will be formed, so that the recast layer changes within a certain range. Under the same machining conditions, the simulation and experimental results agree well with the geometry of the dent. The error of the crater depth is 14.6 %, while the error of the crater diameter is only 5.8 %. Therefore, the established model can provide insights into the material removal and thermal damage formation of NiTi-SMAs machined by WEDM

The anisotropy, heterogeneity, and high hardness of C-f/SiC composite bring great difficulties to its efficient and high-quality processing. Ultrasonic vibration-assisted milling (UVAM) has been shown to positively affect the machining quality of C-f/SiC. This work focuses on the effect of ultrasonic amplitude on 3D needle-punched C-f/SiC composites machining under different fiber cutting angles, and few related studies have been reported. By analyzing the simplified cutting model for both forward and reverse cutting, the influence of ultrasonic amplitude on tool-fiber contact characteristics was investigated. Under fiber cutting angles of 0(circle), 45(circle), 90(circle), and 135(circle), finite element simulations based on the orthogonal cutting model and UVAM experiments with different amplitudes were performed. The results showed that the alternating friction force caused by the harmonic vibration promoted the damaging effect of the tool on the fiber and SiC matrix. At 0(circle) and 135(circle), localized fiber failure occurred early. And at 45(circle) and 90(circle) the shear failure of the fiber was strengthened, which alleviated the damage to the low-strength matrix and the interface layer. Compared with conventional milling, the resultant force showed a downward trend, and typical defects such as pits, fiber pullout, matrix voids, and interface debonding on the machined surface were suppressed in UVAM. As the amplitude increased, the machined surface became smoother, and the surface roughness Sa at all angles decreased by more than 30%. According to the response surface method, the influence order of machining parameters on Sa was obtained: feed rate > amplitude > cutting speed. Sa predictive regression model with only a 5% deviation from the experimental value has good accuracy and reliability. This work shows that reasonable control of ultrasonic parameters and fiber cutting angle in UVAM significantly affects the machining quality improvement of 3D needle-punched C-f/SiC components.

In this study, a simple method without any additional chemical modification is proposed to fabricate underoil superhydrophobic surfaces with micro- and nano-hierarchical structures using a nanosecond laser system. The fabricated surfaces exhibited extreme superhydrophobicity and underoil superhydrophobicity with high contact angles of 153.8 ± 1.5° and 161.3 ± 1.1°, respectively. The results show that even after 20 abrasion cycles, the fabricated surfaces retained water repellency and self-cleaning performance under oil, while the superhydrophobicity in air was not resistant to wear. In addition, the fabricated brass meshes can also be used to separate oil in an oil-water mixture based on the prewetting induced underoil superhydrophobicity after being damaged. The separation efficiency was as high as 97.8%, which made them more appropriate for the oil-water separation than those based on superhydrophobicity. The proposed fabrication method is suitable for large-scale and mass production and provides a new avenue and possibility for further development of robust functional interface materials.

The materials with excellent corrosion resistance performance have attracted interest of researchers, which is of great significance to solve the problem of corrosion of maritime equipment. In this paper, the micro groove (MG) was fabricated on the surface of titanium alloy (TC11) by waterjet-assisted laser (WJAL) ablation. The tests of electrochemical of TC11 fabricated by waterjet-assisted laser (TC11-WJAL) and laser dry (TC11-LD) were carried out. The results of electrochemical experiments showed that the TC11-WJAL had a higher corrosion potential and lower corrosion current density compared with TC11-LD, which indicated the corrosion resistance of TC11-WJAL was significantly improved in 3.5% NaCI solution. The immersion experiments of two samples were also performed using 3.5% NaCI solution to simulate the marine environment. The results exhibited that TC11-WJAL still had a lower corrosion rate compared with TC11-LD after 30 days (TC11-LD-30days) and 60 days (TC11-LD-60days) of immersion, which manifested TC11-WJAL with the characteristic of stable ability of corrosion resistance. Therefore, this WJAL was a facile and effective technology for metal corrosion protection in ocean engineering.

With the rapid development of aerospace technology, the demand for advanced special materials with low density, high mechanical properties and chemical stability has increased rapidly. Ceramic matrix composites are one of such special materials with excellent properties. In this paper, 3D needle-punched C/SiC composites are processed by conventional milling (CM) and ultrasonic vibration-assisted micro-milling (UVAM). The UVAM finite element cutting model was established, and the stress distribution of CM and UAVM was analyzed. Through experimental research, the micromorphology of the machined surface at 0° and 90° fiber cutting angles has been observed, and the fiber fracture in UAVM is more smooth and uniform. In addition, the three-dimensional morphology and surface roughness (Sa) of the machined surface are analyzed.

Preparing an efficient and durable separation material for solving the problem of oily wastewater treatment is of importance but difficult due to the restriction of complex process and secondary pollutants. Herein, the environmentally friendly and low damage waterjet-assisted laser ablation was developed to fabricate robust microstructure on 304 stainless steel mesh (SSM-WJALA) for oil/water separation. This underwater oil-repellent/ underoil water-repellent SSM-WJALA realized the separation of light and heavy oil/water mixtures only under gravity, and exhibited high separation efficiency and great stability to various oil/water mixtures and cyclic separation tests. The detailed analysis of mechanical properties and durability of the material were carried out, which included the tests of friction coefficient, nanohardness, and electrochemical corrosion. The results showed that the surface hardness increased by more than 20%, the corrosion potential increased from - 1.02 V to - 0.49 V, and the corrosion current density decreased by more than two orders of magnitude, compared with SSM-LDA. The application of WJALA technology not only enhanced the properties of mechanical and corrosion resistance of oil-water separation materials but also reduced dust pollution and harm to the health of operators. Therefore, this environmentally friendly and cost-efficient SSM-WJALA provided an effective strategy to solve the problem of oily wastewater treatment especially in harsh conditions and opened an avenue for developing low-cost and facile technology for preparing functional materials.

Ultrasonic-assisted drilling technology (UAD) is an advanced processing method that combines conventional drilling (CD) and ultrasonic-assisted machining, which can improve the machinability of difficult-to-process materials. In this work, UAD micro-hole machining was studied on AISI 4340 steel. Combined with the intersection characteristics of the dynamic trajectory, the chip breaking ability of the cutting edge was analyzed. The influence of processing parameters (spindle speed, feed rate, and amplitude) on the chip shape, chip removal effect, surface quality, and thrust force was studied. The results showed that the chips were mainly the continuous helical shape in CD, while the chips in UAD were mainly fan-shaped and finely broken. In UAD, the ultrasonic cavitation effect significantly promoted the discharge of fine chips. When the ultrasonic vibration was applied, compared with CD, the thrust force in UAD was reduced by 7% to 25.3%. In CD, the size and distribution density of surface defects were more severe than UAD. Compared with CD, the surface roughness of the wall surface in UAD was reduced by 19.2% to 32.4%. When the amplitude was increased to 4.5 μm, the wall surface was smoother without processing marks, and the roughness was reduced by 18.6%. The research is expected to guide the high-quality and high-efficiency manufacturing of micro-holes in difficult-to-machine materials.

The waterjet-assisted laser ablation (WJALA) technology is a novel and environmentally friendly method to obtain the material with the outstanding surface quality. Compared with the laser dry ablation (LDA), the WJALA technology can minimize the thermal damage and obtain a clean cut surface. In this research, the micro-groove was fabricated using WJALA (MG-WJALA) and LDA (MG-LDA), the effect of laser power on the surface morphology was studied. In addition, the nanohardness experiment was carried to test the mechanical performance, the electrochemical experiment was performed to test the corrosion resistance, which in order to explore the different influence of WJALA and LDA on material. The experimental results show that the width and depth of micro-groove were increased with the increasing of laser power under the premise that other parameters remain unchanged. The MG-WJALA had a better surface quality with less machining effects and molten metal accumulation compared with MG-LDA under the same machining conditions. More importantly, The MG-WJALA had the better properties of mechanical and corrosion resistance. In general, the WJALA technology developed in this research has the great prospect in preparation of component near damage free.

ZrO2/Al2O3 porous ceramics were prepared by gel-foaming technique. The rheological property of slurry, the effect of solid content on the microstructure and mechanical property of the porous green bodies and the relationship between the MgO sintering additive content with the compressive strength and porosity of porous ceramics were investigated. The results show when the dispersant content is 0. 4% (mass fraction), ball milling time is 4 h and the pH value is 4, the low viscosity is conductive to gelcasting. The porosity of green body reduces with the increase of solid content. The excessive solid content makes the slurry hard to flow, and the big pores and cracks form during gelcasting process, then the compressive strength of green body decreases. The mechanical properties of porous ceramics are improved with the phase transformation and micro-crack toughening induced by the ZrO2. The densification of pore supports increases, the porosity reduces and compressive strength increases with the increase of sintering additive content. The highest compressive strength is 30 MPa. The porous ceramics with appropriate porosity and high compressive strength can be prepared by introducing suitable contents of ZrO2 and sintering additive.

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.

The materials with extreme wettability have attracted abundant attention all over the world, which can be used for solving the increasingly serious problem of Oily wastewater. Here, a novel technology named waterjet-assisted laser ablation (WJAL) is developed to fabricate microstructures on 304 stainless steel mesh (SSM) for oil-water separation. It is discovered that the obtained rough oxide coating on SSM having approximate 0° contact angle (CA) values of water/oil in the air and more than 150° CA of water in oil/oil in water environment, showing the extreme wettability of superhydrophilicity/ superoleophilicity in air and underwater superoleophobicity/ underoil superhydrophobicity. Based on the special wettability, the separation process of both light and heavy oil-water mixtures are completed utilizing machined SSM with higher separation efficiency and water flux. More importantly, the functional surface maintained the ability of oil-water separation after 30 cycle tests. Therefore, this research presents an advanced method for the one-step process of durable separation material.

Ultrasonic vibration-assisted drilling technology has a wide range of applications in the field of precision manufacturing of difficult-to-process materials. Its principle is to combine high-frequency ultrasonic vibration with conventional drilling technology. Ultrasonic vibration-assisted drilling technology has unique advantages in reducing drilling force, improving surface quality and processing efficiency. In this paper, ultrasonic vibration-assisted drilling technology is used to process micro-holes on the surface of AISI 4340 steel. Through experiments and numerical simulation techniques, the whole process of the dynamic chip formation and the chip morphology are studied. The research results show that when the ultrasonic vibration is applied to the workpiece, the finely divided chips quickly move away from the processing area in a splashing manner. The wall defects of the micro-holes processed by the ultrasonic vibration-assisted drilling technology are suppressed and the surface roughness Ra is improved greatly.