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SiCp/Al composites are widely used in the aerospace field due to their excellent properties. However, the huge difference in the properties of silicon carbide and aluminum matrix materials can easily lead to machining defects. Ultrasonic vibration-assisted machining is an effective method to deal with difficult-to-machine materials. In this study, ultrasonic elliptical vibration is applied to the helical milling of SiCp/Al composites. Firstly, the ultrasonic elliptical vibration-assisted helical milling (UEVHM) cutting-edge trajectory is modeled, and the equation of the UEVHM tool-chip separation condition is established, which lays a foundation for the analysis of the cutting mechanism. Then, the influence of ultrasonic elliptical vibration on the removal mechanism of SiCp/Al composites was investigated by finite element simulation. It was found that UEVHM can reduce the tearing of aluminum matrix and reduce the hole damage by changing the direction of the cutting velocity and the relative position of the cutting edge and particles. Finally, the single-factor experiment was carried out, and the surface morphology and roughness of HM and UEVHM were compared. The influence of process parameters on the surface roughness of UEVHM was analyzed. The experimental results show that compared with HM, UEVHM can reduce surface defects and exit damage, to obtain better surface roughness and exit edge quality. The increase in cutting speed can reduce the roughness, and the increase in pitch and revolution speed will increase the surface roughness. [ABSTRACT FROM AUTHOR]

Though 3D printing shows potential in fabricating complex optical components rapidly, its poor surface quality and dimensional accuracy render it unqualified for industrial optics applications. The layer steps in the building direction and the pixelated steps on each layer's contour result in inevitable microscale defects on the 3D‐printed surface, far away from the nanoscale roughness required for optics. This paper reports a customized vat photopolymerization‐based lens printing process, integrating unfocused image projection and precision spin coating to solve lateral and vertical stair‐stepping defects. A precision aspherical lens with less than 1 nm surface roughness and 1 µm profile accuracy is demonstrated. The 3D‐printed convex lens achieves a maximum MTF resolution of 347.7 lp mm−1. A mathematical model is established to predict and control the spin coating process on 3D‐printed surfaces precisely. Leveraging this low‐cost yet highly robust and repeatable 3D printing process, the precision fabrication of multi‐scale spherical, aspherical, and axicon lenses are showcased with sizes ranging from 3 to 70 mm using high clear photocuring resins. Additionally, molds are also printed to form multi‐scale PDMS‐based lenses. [ABSTRACT FROM AUTHOR]

Current additive manufacturing (AM) techniques for tungsten, such as powder bed fusion and directed energy deposition, often generate parts with rough surfaces. Vat photopolymerization presents a promising alternative for fabricating tungsten structures with high shape fidelity and low surface roughness. However, existing vat photopolymerization approaches suffer from surface defects and low final density, leading to compromised mechanical properties. Therefore, achieving high‐density tungsten structures using vat photopolymerization remains a crucial challenge. This work presents a straightforward and reliable method for fabricating complex, micro‐architected tungsten structures with superior density and hardness. The approach utilizes a water‐based photoresin with exceptional tungsten ion loading capacity. The photoresin is then patterned using digital light processing (DLP) to create tungsten‐laden precursors. A three‐step debinding and sintering process subsequently achieves 3D tungsten structures with dense surface morphology and minimal internal defects. The microstructures achieve a minimum feature size of 35 µm, a low surface roughness of 2.86 µm, and demonstrate exceptional mechanical properties. This new method for structuring tungsten opens doors to a broad range of applications, including micromachining, collimators, detectors, and metamaterials. [ABSTRACT FROM AUTHOR]

The aim of this investigation was to evaluate the effect of etching protocols on bond strength, surface roughness, and mechanical properties of a zirconia-reinforced lithium silicate (ZLS) CAD/CAM-ceramic. In total, 100 bars (ISO 6872), 75 plaques, and 25 cubes were cut from ZLS blocks(Vita Suprinity®). The surfaces were standardized, crystallized and divided into five groups: 1. control (no/treatment-C), 2. 5%-Hydrofluoric-acid (HF)/20 s (HF5%20s), 3.HF5%60s, 4.HF10%20s, and 5.HF10%60s. Flexural strength (FS) (three-point bending test, 1 mm/min), roughness (Pa), and micro-shear bond-strength (µSBS) tests were performed. The data were statistically analyzed with one-way ANOVA, Tukey's test (p ˂ 0.05) and Weibull (FS data). C showed higher Pa (1.176 ± 0.370 µm) than HF10%60s (0.627 ± 0.236 µm) and all other groups. Groups C and 20 s showed the most irregular surface patterns. The FS results were not influenced by etching protocols, while the Weibull modulus was, with the 5%HF groups being the most reliable (m: 5.63/6.70), while C and HF10%60s (m: 2.78/2.73) were the least reliable. All fractures originated from surface defects on the treated side of specimens. The 5%HF groups showed higher µSBS (20 s: 21.35 ± 4.70 MPa; 60 s: 23.50 ± 4.27 MPa) than the 10%HF groups (20 s: 14.51 ± 2.47 MPa; 60 s: 16.54 ± 3.12 MPa) and C (6.46 ± 2.71 MPa). The most prevalent failure pattern was "mixed" for etched groups, and "adhesive" for C. Etching protocols affect the evaluated properties by roughening materials' surface and, in some cases, regularizing surface defects. The best overall outcomes were achieved when applying 5%HF. [ABSTRACT FROM AUTHOR]

In this study, we utilized Selective Laser Melting (SLM) technology to fabricate a magnesium alloy, and subsequently subject it to micro-arc oxidation treatment. We analyzed and compared the microstructure, elemental distribution, wetting angle, and corrosion resistance of the SLM magnesium alloy both before and after the micro-arc oxidation process. The findings indicate that the SLM magnesium alloy exhibits surface porosity defects ranging from 2% to 3.2%, which significantly influence the morphology and functionality of the resulting film layer formed during the micro-arc oxidation process. These defects manifest as pores on the surface, leading to an uneven distribution of micropores with varying sizes across the layer. The surface roughness of the 3D-printed magnesium alloy exhibits a high roughness value of 180 nanometers. The phosphorus (P) content is lower within the film layer compared to the surface, suggesting that the Mg3(PO4)2 phase predominantly resides on the surface, whereas the interior is primarily composed of MgO. The micro-arc oxidation process enhances the hydrophilicity and corrosion resistance of the SLM magnesium alloy, thereby potentially endowing it with bioactivity. Additionally, the increased surface roughness post-treatment promotes cell proliferation. However, certain inherent defects present in the SLM magnesium alloy samples negatively impact the improvement of their corrosion resistance. [ABSTRACT FROM AUTHOR]

Soft-brittle crystals such as KH2PO4 (KDP) pose significant challenges to traditional machining techniques due to their inherent brittleness and substantial sizes. To surmount these challenges, this paper presents the water dissolution combined continuous polishing (WDCCP) method based on the water dissolution principle for achieving high-efficiency and high-quality machining. The WDCCP process is a three-step methodology including initial precision polishing with an aqueous solution, subsequent ultra-precision polishing utilizing a water-in-oil microemulsion, and final cleaning with anhydrous ethanol. Comprehensive analyses of the slurry's microstructure and viscosity are conducted to reveal the surface planarization mechanism. Multiple slurry dispensers ensure a more uniform distribution of various slurries across the interface between the KDP crystal and the pad, thereby enhancing surface quality. Experimental trials conducted on a large numerical control polishing machine demonstrate that precision polishing can eliminate sawn surface defects within a mere 5 min. The ultra-precision polishing significantly reduces the surface roughness root mean square (rms) from 474.974 to 2.779 nm and the peak-to-valley (PV) from 29.859 to 48.949 nm. After WDCCP, the integral morphology of a 180 mm × 180 mm KDP crystal exhibits a PV of 1.938 waves and an rms of 0.264 waves. The WDCCP method emerges as a potent and efficient solution for the machining of large-sized soft-brittle crystals. [ABSTRACT FROM AUTHOR]

The fatigue performance of laser powder bed fusion-fabricated Ti-6Al-4V alloy was investigated using four-point bending testing. Specifically, the effects of keyhole and lack-of-fusion porosities along with various surface roughness parameters, were evaluated in the context of pore circularity and size using 2D optical metallography. Surface roughness of Sa = 15 to 7 microns was examined by SEM, and the corresponding fatigue performance was found to vary by 102 cycles to failure. The S–N curves for the various defects were also correlated with process window examination in laser beam power–velocity (P–V) space. Basquin's stress-life relation was well fitted to the experimental S–N curves for various process parameters except keyhole porosity, indicating reduced importance for LPBF-fabricated Ti-6Al-4V alloy components. [ABSTRACT FROM AUTHOR]

ABSTRACT The high tensile strength and high resistance of nickel‐based superalloy 686 against high temperatures and corrosion rates have made it a widely used in important applications such as the aerospace industry, high pollution‐ and corrosion‐resistance equipment manufacturing and petrochemical industry. Therefore, the machining of this advanced alloy with its unique properties is extremely important and can be challenging. Significant increase in input parameters levels, reduction of machining costs, improvement of surface and subsurface properties and clean production are among the issues that should be considered in dealing with Inconel 686 turning operations. Simultaneous application of advanced tools such as polycrystalline diamond (PCD) and polycrystalline cubic boron nitride (PCBN) and optimised minimum quantity lubrication (MQL) method and evaluating the results obtained with a wide range of output parameters related to machining process performance and tribological properties can be proposed as an innovation and a solution to this problem in this article. This study analyses several output parameters with different speeds and feeds to evaluate the effect of cutting insert type on machining process performance and tribological properties. The output parameters include tool wear, residual stress, cutting zone temperature, surface smoothness, machining forces and workpiece surface defects. The results indicated that using the optimised MQL method reduces the size of lubricant droplets and increases the surface covered by cooling. With these changes, the performance of the machining process and the parameters related to the surface integrity increase significantly. Among the parameters associated with the performance of the machining process, the PCD tool reduces the cutting zone temperature by 23%, the tool wear by 19% and the machining forces by 18% compared to the PCBN tool. In the parameters related to surface integrity, this method reduces the residual stress by 19% and the surface roughness by 9% compared to the PCBN tool. From the production index perspective, the PCD tool can significantly increase the cutting speed and feed rate, reducing production time and costs. [ABSTRACT FROM AUTHOR]

Selective laser melting (SLM) offers an innovative manufacturing approach compared to traditional methods. It has found diverse applications in various fields, ranging from medical devices to aerospace, using a variety of metals. However, products manufactured with the metal AlSi10Mg using the SLM technique have a significant surface roughness defect. Consequently, products produced through SLM necessitate post-processing. In this study, electro-polishing was conducted on AlSi10Mg specimens manufactured at four different inclinations. Surface roughness measurements and 3D scans were performed at various time intervals to observe changes in roughness. It was observed that an increase in electro-polishing time effectively reduced surface roughness. This research provides data on post-processing for three-dimensional structures manufactured using the SLM technique. [ABSTRACT FROM AUTHOR]

Through Silicon Via (TSV), a kind of 3D packaging technique, can improve chip integration based on "More than Moore" scheme. The larger copper area ratio at the TSV barrier layer interface requires strong adjustability of the removal rate selection ratio of copper, tantalum and TEOS–SiO2, and stronger surface defect control and surface profile correction capabilities. In this paper, the effects of guanidine hydrochloride (GH) and 2,2′-[[(Methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol (TT-LYK) system on the tunability of Ta and Cu removal rate in chemical mechanical polishing (CMP) of TSV wafer barrier material were studied. GH can complex TaO 4 3 - , while TT-LYK can form a protective film on the surface of Cu, thereby achieving rate regulation. The results showed that when the concentration of GH increased from 0 to 2 wt%, the removal rate selectivity ratio of Ta and Cu raised from 1.02:1 to 1.26:1. When the concentration of TT-LYK increased from 2.5 to 10 mmol/L, the removal rate selectivity ratio of Ta and Cu increased from 1.33:1 to 1.79:1, which verified that the GH and TT-LYK systems can efficiently regulate the rate and rate selection ratio of Ta and Cu. Surface roughness for both metals decreased from pre-polishing values of 5.03 nm to post-polishing values of 0.37 nm for Ta, from pre-polishing values of 5.33 nm to post-polishing values of 1.26 nm for Cu indicating that GH and TT-LYK systems significantly improved the surface quality. [ABSTRACT FROM AUTHOR]

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This experiment was designed to study the surface defects of 20 % volume fraction SiCp/Al composites after grinding and to provide the necessary experimental results for optimizing grinding parameters. Based on the two-dimensional cutting simulation model of single particle, the main damage of particles in matrix during machining has been investigated. The particles in SiCp/Al composites are randomly distributed and the tool will cut through multiple particles in a single cut and at different locations. A single particle cutting model was developed to study the different states of particle fragmentation by cutting through the upper, middle and lower parts of the particles respectively. Nine groups of parameters were obtained by orthogonal experimental design, and electroplated diamond grinding rod was used as the grinding tool for grinding experiment. In order to get the best surface grinding parameters, a ternary linear regression equation was selected to be established. Significance test could prove the reliability of the linear regression equation, and then, the optimal solution of this equation can be calculated by the MATLAB genetic algorithm toolbox. From the simulation and experimental results, it can be seen that the stress begins to concentrate when the cutting tool is close to the particle, and when the cutting stress exceeds the ultimate compressive strength, the particle is broken and part of it will be pulled out. The breakage of particles is not one-time, but requires many times of large cutting force to break the particles in sections, and the repeated breakage of particles eventually leads to the generation of overall cracks. [ABSTRACT FROM AUTHOR]

In order to improve the micro-grinding quality of 2.5D carbon fiber-reinforced silicon carbide ceramic matrix (2.5D Cf/SiC) composite materials, their characteristics under different grinding parameters were investigated in this study. Firstly, theoretical models for the undeformed chip thickness and micro-grinding force were established. Then, orthogonal and single-factor experiments were conducted using 0.9-mm-diameter micro-grinding tools electroplated with 500# diamond abrasive particles. Through the range and variance analysis of the orthogonal experimental results, the order in which grinding parameters affect the grinding performance of 2.5D Cf/SiC composites was obtained. Single-factor experimental results indicate that the theoretical model of the micro-grinding force shows consistent trends with the experimental results. As the grinding depth ap and the feed speed vw increase, the grinding force, the surface roughness Ra, and surface defects after micro-grinding also increase, indicating that the grinding performance of 2.5D Cf/SiC composites gradually deteriorates. On the contrary, increasing the grinding speed vs can improve their grinding performance. Based on the established theoretical model, the reasons for the variation of grinding force, surface morphology, and surface roughness with grinding parameters were elaborated. This research would supply a basis for understanding the micro-grinding performance and provide guidance for improving the micro-grinding quality of 2.5D Cf/SiC composites. [ABSTRACT FROM AUTHOR]

High-volume fraction silicon carbide particle-reinforced aluminum (SiCp/Al) has a promising application for its high specific strength, wear resistance, and thermal conductivity. However, SiCp/Al components with a high-volume fraction are prone to poor surface quality and defects such as fractures, cracks, and micro-pits. It has been reported that ultrasonic-assisted grinding machining (UAG) helps to improve the quality of SiCp/Al machined surfaces. However, the differences between SiCp/Al with different volume fractions obtained by UAG machining are not clear. Therefore, a comparative study of surface roughness, morphology, and cutting force was carried out by UAG machining on SiCp/Al samples with volume fractions of 45% and 60%. Compared to the 45% volume fraction SiCp/Al, the 60% volume fraction SiCp/Al has a higher cutting force and roughness under the same machining parameters. In addition, experiments have shown that cutting forces and surface roughness can be reduced by increasing the tool speed or decreasing the feed rate. UAG machining with an ultrasonic amplitude within 4 μm can also reduce cutting forces and surface roughness. However, more than 6 μm ultrasonic amplitude may lead to an increase in roughness. This study contributes to reasonable parameter settings in ultrasonically-assisted grinding of SiCp/Al with different volume fractions. [ABSTRACT FROM AUTHOR]

In micro grinding, the size of the micro grinding tool largely determines the minimum size of the microstructures that can be machined. However, most researches about micro grinding use grinding tools with a diameter more than 300 μm. In this study, the grinding properties of titanium in ultra-small-grinding (USG) on no more than 100 μm scale were investigated. A grinding force model considering the effects of micro scale and abrasive grain size was proposed. Corresponding experiments were conducted with self-prepared USG tools with diameters 100 μm. Electroplating technology was used to fix abrasive grains to prepare the USG tools, and the electrochemistry preparation processing of the USG tool was revealed. The effectiveness of the grinding force model was proved by the experimental results. The influences of grinding parameters on the surface and grinding forces were studied. The grinding force on the x-axis is the largest in three directions, which decreases with the increasing of rotation speed and increases with the increasing of feeding velocity. The material removal ability of up grinding is better than that of down grinding in USG. As the feeding velocity increases and rotation speed decreases, surface defects increase. There is much individual sheet-like material melted and adhered to up grinding surface, and the straight serrated contour line is prone to be produced by up grinding. And there is much fish scale like material fusion layer deposits on down grinding surface, and the inclined wavy contour line is prone to be produced by down grinding. After USG, the oxygen element content on the grinding surface increases by more than 10 % due to grinding heat. • Grinding performance of the small grinding tool with diameter 100 μm was studied. • The effects of micro scale and grain size were considered in modeling. • Small grinding tool with diameter 100 μm was prepared by electrochemistry method. [ABSTRACT FROM AUTHOR]

Mg 2 Si/Al composites have wide application prospects in aerospace and automotive industries. However, many defects often remain on the machined surface after micro cutting. In this paper, the formation mechanism of surface defects of Mg 2 Si/Al composites by micro cutting was studied by finite element (FE) simulations and machining experiments. Considering the real microstructure characteristics of Mg 2 Si particles, 2D FE simulations of Mg 2 Si/Al composites in micro cutting were carried out and then verified by corresponding cutting experiments. The simulation results and experimental data reveal the relationship between damage and deformation behavior of Mg 2 Si particles and formation mechanism of surface defects. In addition, the effects of cutting parameters such as depth of cutting (DoC), cutting speed and volume fraction of particles on residual defects of machined surfaces were studied. The results show that with lower DoC and higher cutting speed, the residual defects and surface roughness are significantly reduced, especially machining the composites with smaller particle size and lower volume fraction. The research findings provide a theoretical basis for reasonable selection of machining parameters and improving the machinability of Mg 2 Si/Al. [Display omitted] • The geometric models for FE simulation of Mg 2 Si/Al composites in micro cutting process were established. • The mechanism of damage and removal of Mg 2 Si/Al particle in micro cutting process was analyzed by simulation. • The relationship between characteristics of mechanism of particle damage and formation of surface defects were discussed. • The influence of the DoC, cutting speed and volume fraction of the particles on the machined surface quality was studied. [ABSTRACT FROM AUTHOR]

In electrical discharge machining (EDM), it is a much more effective method to improve working characteristics by changing the input process of pulse energy. However, it has not been investigated enough whether pulse form is the most adequate or not. In this study, the effect of superimposed pulse current waveform and its parameter on surface integrity was investigated. The surface topography, roughness, microstructure, white layer thickness, and residual stress were analyzed and discussed. Moreover, the material removal rate was also tested and compared. The results show that with the backward movement of the superimposed pulse current, the material removal rate and surface roughness decrease, while the white layer thickness, residual stress, and surface defects increase. The current waveform has little influence on microstructure. Under the same pulse discharge energy and pulse-on time, the samples processed by superimposed pulse current waveform instead of rectangular current waveform can obtain a thinner white layer, lower residual stress, fewer surface defects, and high surface roughness. With the increase of superimposed pulse-on time and current, the surface integrity becomes worse due to the increase of pulse energy. This paper provides a guide to the development and selection of EDM discharge current waveforms in EDM. [ABSTRACT FROM AUTHOR]

Tungsten alloys have excellent properties such as high strength, high hardness, high melting point, and high specific gravity, which have been widely used in many cutting-edge scientific fields such as aerospace and military. In order to solve the problems of poor surface quality and severe tool wear in tungsten alloy cutting, conventional dry turning and electroplastically assisted dry turning with different electrical parameters were carried out to study the effects of electroplasticity on surface roughness, surface defects, tool wear, and chip morphology of W93NiFe alloy. The results showed that the electroplastically assisted dry turning process improved the surface quality of W93NiFe alloy. The surface roughness value decreases gradually with the increase of pulse voltage and reaches the minimum value at the pulse voltage of 80 V, with the maximum reduction of 38.94% compared with conventional dry turning. However, too high pulse voltage causes an increase in the surface roughness value. When the pulse voltage was increased from 80 to 90 V, the surface roughness increased by 29.63%. At a pulse voltage of 70 V, the surface roughness value did not change much for different pulse current frequency conditions. Compared to conventional dry turning, electroplastically assisted cutting reduced the degree of machined surface defects in the material and tool wear, but it could lead to the formation of built-up edge at the tool tip. After the pulsed current was applied, the chip curl radius and pitch were smaller, and it was easier to form strip chips with longer transverse lengths. The results provide a reliable reference for electroplastically assisted cutting in the future. [ABSTRACT FROM AUTHOR]

Soft abrasive flow (SAF) finishing has advantages in precise processing for titaniferous alloy parts with large-area surfaces. However, the processing efficiency and surface quality of current SAF methods require to be improved. To address the issues, a novel gas–liquid-solid three-phase rotary abrasive flow polishing method (RGLSP) is proposed based on the microbubble cavitation effect. Referring to the energy conservation principles of bubbles group movement, an improved realizable k-ε turbulence model is set up. Based on the above model, a mechanical dynamic model of the machining apparatus is established to obtain the flow field distribution of different structural parameters. The simulated results show that the pitch-down angle determines the distribution of the rotary flow field, and an optimized processing apparatus is developed. The machining experiments show that the proposed RGLSP method can improve the machining efficiency by 60%, and the surface roughness can reach Ra 0.1 μm with lower surface defects. The RGLSP can provide an important reference direction for low-carbon emission processing. [ABSTRACT FROM AUTHOR]

CMSX-4 nickel base superalloy is the second-generation alloy of this single crystal, which has improved its mechanical properties due to the lack of grain boundaries. According to the working conditions in using this superalloy, achieving less surface defects and lower surface roughness after the manufacturing process is very important. Therefore, the comparison of the surface of this superalloy after grinding, wire electro discharge machining (WEDM) and electrochemical machining (ECM) has been investigated by scanning electron microscope (SEM) and surface roughness. Surface roughness after WEDM, ECM and grinding are 3.337, 0.549, and 0.458 micro-meter, respectively. ECM and grinding processes are suitable from the point of view of surface roughness. On the other hand, in the SEM images after ECM, the defects caused by this process were not observed (compared to the other two processes). Besides, hardness after WEDM, ECM and grinding are 38.9, 39.7 and 40.1 HRC respectively. To conclude, the ECM process has desirable results and is a suitable alternative process for manufacturing parts with smooth surface and less surface defects. [ABSTRACT FROM AUTHOR]

Optical glass BK7 is an amorphous crown glass widely used in the aviation industry and high-power laser equipment due to its mechanical and optical properties. With the hard surface and brittle nature, the grinding process is one of the standard machining methods of BK7. Fracture is a dominant mechanism in removing brittle materials, which causes surface and sub-surface defects in the workpiece. Prediction of the depth of sub-surface damage (SSD) that has occurred allows the optimal reduction or even elimination of sub-surface defects in the finish grinding stage. This research aimed to comprehensively investigate the multifaceted influence of seven pertinent parameters on the depth of sub-surface damage (SSD) and surface roughness (SR) resulting from the grinding process. More specifically, it delved into the effects of the grinding wheel's movement direction under varying contact conditions, including angular grinding, vertical grinding, and face grinding, focusing on three critical aspects: the maximum undeformed chip thickness, depth of sub-surface damage, and resulting surface roughness. The contact conditions between the grinding wheel and the workpiece were systematically classified into four groups based on predetermined input parameters to facilitate in-depth analysis. Subsequently, the resulting outputs were evaluated and compared across these diverse contact conditions. The comparative examination between theoretical equations and experimental findings unveiled a maximum deviation of 10 % in SSD depths and 15.61 % in SR estimations. Furthermore, this study's experimental assessments identified nonlinear and monotonic relationships between the depth of SSD, surface roughness, and the maximum undeformed chip thickness (h m). The experimental relationships and the measured results notably highlighted observed discrepancies of 4.27 %, 10 %, and 10 % for the respective parameters (SSD, surface roughness, and h m). • The effect of the spiral speed on the surface and subsurface defects had not been evaluated with the cup grinding wheel. • Maximum undeformed chip thickness (h m) relations were modified based on the grinding conditions. • The SSD depth and the SR value in four grinding conditions with cup wheels were theoretically and experimentally evaluated. • The SR values and SSD depth can be changed according to the workpiece radius based on the grinding conditions. • Monotonic non-linear relations are obtained based on the experimenral results to calculate SSD depth in terms of SR value. [ABSTRACT FROM AUTHOR]

This article presents a comprehensive experimental investigation into the drilling behavior of Nomex®, a type of aramid fiber. The study specifically examines the impact of various cutting parameters and drill bit types on drilling outcomes. While Nomex® offers many advantages, difficult chip evacuation during drilling of aramid fiber composites can lead to surface defects and delamination. The research aims to explore how drilling parameters—such as spindle speed, feed rate—and four distinct drill bit types affect drilling performance. The analysis encompasses factors such as thrust force, torque, and surface roughness, studied under different drilling conditions and with various drill bit types. Moreover, the research assesses peeling and push-out delamination factors to gain insights into drill bit and coating characteristics. An examination of burr and chipping further enhances the comprehension of drilling performance. To determine the most effective drilling conditions, the study employs multi-response optimization. The optimal drilling performance is achieved with a combination of a 0.1 mm/rev feed rate, 1402.82 r/min spindle speed, and HSS-TiN drill type. This configuration successfully integrates responses, resulting in a composite desirability value of 0.95. [ABSTRACT FROM AUTHOR]

The special characteristics of the laser deposition manufacturing (LDM) process for forming titanium alloys (Ti6Al4V) lead to significant anisotropy in the mechanical properties of the alloy. The existence of anisotropy leads to different processing efficiency and processing performance in different processing directions. In this study, the cutting force, cutting temperature, and surface integrity of the additive titanium alloy machined by LDM at five angles of 0, 22.5, 45, 67.5, and 90° to the deposition direction were comparatively studied. Tensile properties, cutting force, cutting temperature, surface topography, surface roughness, and work hardening were used as evaluation indicators to observe the surface layer of the material after end milling under the same milling parameters. The results showed that the smallest grain size at the machining angle of 22.5° resulted in slightly higher cutting forces, cutting temperatures, and surface roughness than the other four groups. Meanwhile, large surface defects such as scratches and plowing were observed on the surface of the specimens at 22.5°, with a higher degree of machining hardening and deeper hardening layer depth. It proves that the anisotropy of the additive titanium alloy itself will have a greater impact on the cutting force, cutting temperature and surface integrity during its machining. [ABSTRACT FROM AUTHOR]

SiCp/Al is a difficult-to-machine material that makes it easy to produce surface defects during machining, and researchers focus on reducing the surface defects. Vibration-assisted machining technology is considered an effective method to reduce surface defects by changing the trajectory and contact mode of the abrasive. Aiming at the problem of SiCp/Al processing technology, a vibration-assisted lapping device (VLD) is designed, and elliptical motion is synthesized by a set of parallel symmetrical displacement output mechanisms. The working parameters of the device were tested by simulation and experiment, and the lapping performance was verified. Then, the effects of removal characteristics and process parameters on surface roughness and lapping force were analyzed by simulation and experiment. Simulation and experimental results show that frequency and amplitude that are too low or too high are not conducive to the advantages of NVL. The best surface quality was 54 nm, obtained at A = 8 μm and f = 850 Hz. [ABSTRACT FROM AUTHOR]

Single-crystal sapphire (α-Al2O3) has been widely used in semiconductor, optics, communication, national defense, and other fields. Before application, an ultra-smooth surface which is scratch free and subsurface damage free is essential. Furthermore, the sapphire has unique qualities such as significant rigidity and chemical stability, which make it extremely arduous to process. Chemical mechanical polishing (CMP) is recognized as the final process to reduce the roughness and eliminate surface defects of a sapphire surface. In this review, the materials and equipment used for the chemical polishing of a sapphire wafer are summarized, and the surface nanoscale changes of sapphire wafer are reviewed from the angles of regulating polishing-process parameters, composition of polishing slurry including that which is nano-abrasive, a pH regulator, a complexing agent, and other additives, as well as hybrid CMP technologies. The outlook and future applications are also summarized. [ABSTRACT FROM AUTHOR]

Electrothermal instability is responsible for degrading numerous applications of pulsed-power technology, yet the initial conditions from which it grows are not well understood. For the first time, metal surfaces have been tracked from characterization to self-emission. This reveals no clear correlation between non-uniform thermal emissions and surface metallurgical defects or crystallographic grains, while correlations are observed with surface topography for 5N metal but not 6061 metal. For 5N metal, surfaces with average roughness as small as 5 nm still admit thermal perturbations with δ T / T > 0.1. [ABSTRACT FROM AUTHOR]

Abrasive suspension jet (ASJ), an accurate cold-cutting technology, can address traditional processing issues relating to carbon-fiber-reinforced plastics (CFRPs) like tool wear, interlayer delamination, large heat-affected zone, and low surface roughness. This study employed the use of an ASJ to cut CFRPs and an ultra-depth optical microscope to scan the cut surface to analyze interlayer delamination, surface roughness, kerf taper, and shoulder damage. Regression analysis was conducted to establish a prediction model for cutting quality based on surface roughness, kerf taper, and shoulder damage. Various types of CFRP cutting quality were analyzed using jet parameters. It was found that the use of ASJ to process CFRP results in the following defects: The range of surface roughness variation is from 0.112 μm to 0.144 μm. Surface roughness is most influenced by stand-off distance, followed by traverse speed and jet pressure. The range of kerf taper variation is from 4.737° to 10.1°. Kerf taper is most influenced by stand-off distance, followed by jet pressure and traverse speed. The range of shoulder damage variation is from 3.384 μm2 to 10 μm2. Shoulder damage is most influenced by jet pressure, followed by traverse speed and stand-off distance. A prediction model for cutting quality was developed based on surface roughness, kerf taper, and shoulder damage, providing data support for ASJ cutting of CFRPs. The optimal parameter combination is a stand-off distance of 1 mm, a jet pressure of 30 MPa, and a traverse speed of 30 mm/min. [ABSTRACT FROM AUTHOR]

To investigate the micro-grinding process and performance of 2.5D Cf/SiC composites and 2.5D SiCf/SiC composites in depth, single-factor micro-grinding experiments were conducted by using SiC ceramics as a comparison. Differences in the material removal process, surface microstructure, surface roughness, and grinding force of the three materials under the same grinding parameters were comparatively analyzed. The results indicate that crack propagation is severe during the micro-grinding process of SiC ceramics. The ground surface is uneven, accompanied by pit defects and large surface roughness Ra. However, the presence of reinforcing fibers and interfaces in the two types of composites can inhibit crack propagation or change their extension directions. Therefore, their surfaces are smooth and flat after grinding, with small defects and low surface roughness Ra. In addition, the grinding processes of the two composites are both related to fiber orientation. There are differences in crack propagation paths and fiber fracture positions in the weft fiber layer and the radial fiber layer, which result in different forms of grinding defects. During micro-grinding, the real-time force signals of 2.5D Cf/SiC composites and 2.5D SiCf/SiC composites are relatively stable, while the signals of SiC ceramics have a large number of spikes. The average micro-grinding force of the three materials is: SiC ceramics > 2.5D SiCf/SiC composites > 2.5D Cf/SiC composites. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) allows for optimized part design, reducing weight compared to conventional manufacturing. However, the microstructure, surface state, distribution, and size of internal defects (e.g., porosities) are very closely related to the AM fabrication process and post-treatment operations. All these parameters can have a strong impact on the corrosion and fatigue performance of the final component. Thus, the fatigue-corrosion behavior of the 3D-printed (L-PBF) AlSi10Mg aluminum alloy has been investigated. The influence of load sequence (sequential vs. combined) was explored using Wöhler diagrams. Surface roughness and defects in AM materials were examined, and surface treatment was applied to improve surface quality. The machined specimens showed the highest fatigue properties regardless of load sequence by improving both the roughness and removing the contour layer containing the highest density of defect. The impact of corrosion was more pronounced for as-printed specimens as slightly deeper pits were formed, which lowered the fatigue-corrosion life. As discussed, the corrosion, fatigue and fatigue-corrosion mechanisms were strongly related to the local microstructure and existing defects in the AM sample. [ABSTRACT FROM AUTHOR]

Material extrusion (ME) technique has been one of the most popular additive manufacturing techniques because of its environmental friendliness, low cost, simple operation, and so forth. However, significant surface defects occur on ME parts due to the discontinuity between adjacent layers. For this reason, a new method, using ultrasonic‐vibration machining, was innovatively proposed to improve the ME parts' surface quality. A theoretical surface roughness (SR) model of the ME parts processed by using ultrasonic vibration was established. An ultrasonic‐vibrating ME equipment was then set up by refitting an ordinary one and the samples built without and with ultrasonic‐vibration machining utilized were prepared, respectively. With the laser microscope, the built parts' SR was tested and determined. Compared the predicted SR results with the measured ones, the theoretical model was verified. The influence of different ultrasonic vibration on the surface quality of ME parts was also discussed, clarifying the corresponding mechanism. [ABSTRACT FROM AUTHOR]

A 3D printer produces parts from CAD models. The printout must be checked for defects. We present a surface defect detection algorithm that constructs a 3D mesh of the printout by multi-view scanning and compares it to the part CAD model. It computes and displays the distance from each vertex of the printout mesh to the closest point on the part model. These distances comprise the global deviation of the printout from the model. When the error is within a threshold, the algorithm compares the curvature at each printout vertex to that at the closest part point. Qualitative differences in curvature indicate local defects, such as blobs, cracks, surface roughness, and faded embossing and engraving. The results are grouped into local defect regions that are displayed. We demonstrate the algorithm on metal printing and on PLA 3D printing. [ABSTRACT FROM AUTHOR]

In this paper, we develop fabrication technology and study aluminum films intended for superconducting quantum nanoelectronics using AFM, SEM, XRD, HRXRR. Two-temperature-step quasiepitaxial growth of Al on (111) Si substrate provides a preferentially (111)-oriented Al polycrystalline film and reduces outgrowth bumps, peak-to-peak roughness from 70 to 10 nm, and texture coefficient from 3.5 to 1.7, while increasing hardness from 5.4 to 16 GPa. Future progress in superconducting current density, stray capacitance, relaxation time, and noise requires a reduction in structural defect density and surface imperfections, which can be achieved by improving film quality using such quasiepitaxial growth techniques. [ABSTRACT FROM AUTHOR]

In advanced packaging technology, the micro bump has become an important means of chip stacking and wafer interconnection. The reliability of micro bumps, which plays an important role in mechanical support, electrical connection, signal transmission and heat dissipation, determines the quality of chip packaging. Surface morphological defects are one of the main factors affecting the reliability of micro bumps, which are closely related to materials and bonding process parameters. In this paper, the electrodeposition process of preparing gold bumps is simulated at the atomic scale using the Kinetic Monte Carlo method. The differences in surface morphology and roughness of the plated layer are studied from a microscopic perspective under different deposition parameters. The results show that the gold micro bumps prepared by electrodeposition have better surface quality under conditions of lower deposition voltage, lower ion concentration and higher plating temperature, which can provide significant guidance for engineering applications. [ABSTRACT FROM AUTHOR]

Electrochemical polishing (ECP) is effective for improving the surface quality of additively manufactured (AM) parts. However, ECP effects of AM parts manufactured from varied materials show significant differences owing to the complexity of phase composition, chemical composition, and specific surface defects. Accordingly, this paper compares the electrochemical polishing (ECP) results and mechanisms of the laser powder bed fusion (LPBF) additive manufacturing (AM) of HR-2 stainless steel (single-phase) and AlSi10Mg (multi-phase). Both kinds of LPBF parts show a significantly smoother surface after the ECP process. Following ECP, the Sa of HR-2 was reduced from 11.50 μm to 1.73 μm, while the Sa of AlSi10Mg was reduced from 14.91 μm to 4.70 μm. Notably, compared with LPBF HR-2, LPBF AlSi10Mg forms a solid viscous layer due to the buildup of polishing products after ECP, thus inhibiting the diffusion and reaction of the ions during the polishing process, resulting in a decrease in the polishing effect. Therefore, an in situ mechanical brushing (ECMP) targeting the product layer is conducted along with the ECP, and the surface roughness of the LPBF AlSi10Mg is further reduced to 2.19 μm. Due to the properties of the viscous layer, such an ECMP method is only suitable for the AlSi10Mg but not the HR-2 to further reduce the surface roughness as the ECMP LPBF HR-2 surface quality deteriorated from 1.73 to 2.51 μm. [ABSTRACT FROM AUTHOR]

Wire electrical discharge machining (WEDM) is widely preferred for machining difficult-to-cut materials like Ti6Al4V. In the present study, current, pulse-off-duration (Toff), and pulse-on-duration (Toff) were identified as vital input factors for the WEDM process of Ti6Al4V. Material removal rate (MRR) and surface roughness (SR) were selected as output measures for the study. The experiments were carried out by employing Taguchi's L9 design at three levels. Empirical models were generated, which give the relationship between the input and output factors of the process. To check the acceptability of the model terms, analysis of variance (ANOVA) was used. The regression mode was observed to be significant for the output measures. For MRR, Toff was recorded as the highly significant factor affecting the response values with 74.95% impact, followed by Ton with 16.39%, and current with 6.56%. In the case of SR, Ton was found to be a highly significant factor with a 50.24% impact, followed by current with 43.99%, and Toff with 1.47%. Further, multi-objective optimization by using the HTS technique was performed. The effect of expanded graphite (EG) nano-powder has been studied on the output factors of MRR and SR. The use of EG nano-powder was found to improve WEDM operations as MRR was increased by 45.35%, and simultaneously, SR was reduced by 36.16%. Lastly, the surface morphology of the machined surface was investigated by employing SEM to understand the effect of EG nano-powder. The results have shown a reduction in surface defects by using EG nano-powder compared to the conventional WEDM process. [ABSTRACT FROM AUTHOR]

Silicon carbide-reinforced aluminum matrix composites (SiCp/Al) have excellent physical properties, but the presence of SiC particles in the reinforcing phase causes severe tool wear and more serious surface defects during cutting, which seriously hinders the machining efficiency of SiCp/Al composites. To improve the surface quality of SiCp/Al composites and improve the tool wear problem, it were carried out that simulation and experimental verification of the milling tool parameters of SiCp/Al composites and experimental study of CMQL with the selected tool parameters. The results show that the cutting tool with rake angle of 4° and relief angle of 10° can achieve efficient cutting of SiCp/Al composites. The CMQL condition can effectively reduce the surface roughness, improve the surface microstructure, reduce tool wear and increase tool life; The increase of cutting speed can reduce the machined surface roughness, while the increase of feed and cutting depth will lead to the increase of surface roughness. [ABSTRACT FROM AUTHOR]

While investigating the variator transmission of vehicles, the relationship between the technological and service parameters of the working surfaces of conical disks treated by technological methods was established. The service properties are proposed to be enhanced by Regular MicroReliefs (RMRs) created on such surfaces. The optimal technological processing conditions were found, which allow retaining the greatest amount of lubricant. The causes of surface defects, formed on the working surfaces of conical disks of the Continuously Variable Transmission (CVT), are systematized and classified. The wear resistance of such surfaces is proposed to be enhanced by technological methods, in particular, by forming partially RMRs on them. Their application facilitates relaxation processes on the material near to the surface, reduces shear stresses and strains, thus preventing the formation of burrs and extending the life of the conical disks of the CVT. A novel approach for obtaining the toolpaths of the deforming element, based on the so-called "Commis-Voyageur problem" algorithms, is employed in order to research the possibilities for involving that methods in toolpath generation. Dependences between the partial RMR's formation conditions (deforming forces and feedrate) and microgeometric quality parameters are established. The latter include surface roughness, with a partially RMR applied onto the face surfaces of the test specimen (rotary body). It is found that these microreliefs enhance the ability of oil retaining in plastically deformed traces, formed over the operational surfaces, in comparison with those, that are processed by traditional cutting methods, as turning for example. [ABSTRACT FROM AUTHOR]

Unidirectional electromagnetic modes have significant potential for routing electromagnetic radiation and are highly desirable for various applications, such as isolators, splitters, and switches. In this study, we theoretically investigate surface magnetoplasmons (SMPs) in a four-layer structure consisting of a perfect magnetic conductor (PMC)–semiconductor–dielectric–metal, which exhibits complete unidirectional propagation. We extend this structure to a 3D model by decreasing the width of the PMC-semiconductor part to an appropriate value and demonstrate that the SMPs in the proposed 3D waveguide retain complete unidirectional propagation. Our findings indicate that the unidirectional SMPs are robust to backscattering caused by surface roughness and defects. Moreover, the proposed 3D waveguide can be efficiently coupled to conventional microstrip line waveguides. Our results (based on the numerical method) demonstrate that SMPs based on semiconductors offer a promising approach to creating devices with new functionalities in the terahertz regime below the diffraction limit. [ABSTRACT FROM AUTHOR]

The surface integrity of bearing steel materials largely determines the life of mechanical parts like bearings and gears. Optimizing the process parameters or applying surface modification technology can improve the surface integrity of materials. In this paper, the definitions and characteristics of the evaluation parameters of surface integrity and their influences on mechanical part performance were reviewed. The influences of machining processes (forging, cold rolling, heat treatment, turning, grinding, and super-finishing) for bearing steel materials on parameters related to surface integrity including metal streamline distribution, surface roughness, surface waviness, surface defects, micro-structure, residual stress, and micro-hardness were summarized. Several typical surface modification technologies applied to bearing steel materials were summarized, including surface coating technology, chemical heat treatment technology, ion implantation technology, reinforced grinding technology, shot peening technology, and composite modification technology. Finally, two new surface modification technologies which can be applied to bearing steel materials in the future were introduced (ultrasonic surface rolling process and laser shock peening). It can provide certain research directions and theoretical references for improving the surface integrity of bearing steel material in this paper. [ABSTRACT FROM AUTHOR]

Abrasive waterjet is proposed as a promising technique for high-efficient cutting of hybrid composite-metal structures. This study comprehensively studied the effects of machining strategies (including different traverse speed, hydraulic pressure and stack configuration) on material removal mechanisms, kerf characteristics and surface integrity during abrasive waterjet slotting of thick CFRP/aluminum stacks. Power-to-speed ratio (Ė/u) was firstly employed as a significant parameter to understand the relationship between machining parameters and kerf width/surface roughness variation. Experimental results demonstrated that kerf geometry was sensitive to processing parameters, and kerf profile was closely related to the stacking configuration. The kerf width increased significantly with higher Ė/u level before reaching the threshold value. A rapid decrease of surface roughness was observed at relatively lower Ė/u value. "V" and "X" shaped kerf profiles were formed on CFRP/Al and Al/CFRP stacks respectively, and the corresponding formation mechanisms of specific kerf profile were further investigated. • Abrasive waterjet was proposed to slot thick CFRP/Al stacks with high efficiency. • Different surface formation mechanisms were investigated during AWJ cutting composites/metallic stacks. • Power-to-speed ratio was employed to understand the effects of machining parameters on surface quality. • "V" and "X" shaped kerf profiles were formed on CFRP/Al and Al/CFRP stacks, respectively. • Various surface defects were observed under different strategies and corresponding mechanisms were investigated. [ABSTRACT FROM AUTHOR]

The constant effort of all metal alloy manufacturing technologies and processes is to improve the resulting quality of the processed part. Not only the metallographic structure of the material is monitored, but also the final quality of the cast surface. In foundry technologies, in addition to the quality of the liquid metal, external influences, such as the behaviour of the mould or core material, significantly affect the cast surface quality. As the core is heated during casting, the resulting dilatations often lead to significant volume changes causing stress foundry defects such as veining, penetration and surface roughness. In the experiment, various amounts of silica sand were replaced with artificial sand and a significant reduction in dilation and pitting of up to 52.9% was observed. An important finding was the effect of the granulometric composition and grain size of the sand on the formation of surface defects from brake thermal stresses. The specific mixture composition can be considered as an effective prevention against the formation of defects instead of using a protective coating. [ABSTRACT FROM AUTHOR]

Surface quality of fused silica, particularly surface defect and surface roughness, is a key factor affecting the performance of high‐power laser and short‐wave optical instrument, and so on. Herein, the super smooth surface of fused silica with roughness of sub‐angstrom level and exceedingly few submicron defects was achieved by using ultrafine nano‐CeO2 with primary particle size less than 4 nm, low secondary particle agglomeration strength, and high Ce3+ concentration. Furthermore, CeO2 involve in polishing process in the form of primary particle was certified by experiment. Moreover, the cause for the generation of submicron defects on fused silica surface was investigated for the first time from the perspective of secondary particle agglomeration strength of CeO2. The concentration of Ce3+ in CeO2 was characterized by the redshift of the band‐gap energy, and the analysis of material removal rate (MRR) and contact angle of polished fused silica shows that Ce3+ enhances MRR through increasing the silanol group on fused silica. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to study the functionality of additively manufactured (AM) parts, mainly depending on their dimensional accuracy and surface finish. However, the products manufactured using AM usually suffer from defects like roughness or uneven surfaces. This paper discusses the various surface quality improvement techniques, including how to reduce surface defects, surface roughness and dimensional accuracy of AM parts. Design/methodology/approach: There are many different types of popular AM methods. Unfortunately, these AM methods are susceptible to different kinds of surface defects in the product. As a result, pre- and postprocessing efforts and control of various AM process parameters are needed to improve the surface quality and reduce surface roughness. Findings: In this paper, the various surface quality improvement methods are categorized based on the type of materials, working principles of AM and types of finishing processes. They have been divided into chemical, thermal, mechanical and hybrid-based categories. Research limitations/implications: The review has evaluated the possibility of various surface finishing methods for enhancing the surface quality of AM parts. It has also discussed the research perspective of these methods for surface finishing of AM parts at micro- to nanolevel surface roughness and better dimensional accuracy. Originality/value: This paper represents a comprehensive review of surface quality improvement methods for both metals and polymer-based AM parts. [ABSTRACT FROM AUTHOR]

Surface quality of fused silica, particularly surface defect and surface roughness, is a key factor affecting the performance of high‐power laser and short‐wave optical instrument, and so on. Herein, the super smooth surface of fused silica with roughness of sub‐angstrom level and exceedingly few submicron defects was achieved by using ultrafine nano‐CeO2 with primary particle size less than 4 nm, low secondary particle agglomeration strength, and high Ce3+ concentration. Furthermore, CeO2 involve in polishing process in the form of primary particle was certified by experiment. Moreover, the cause for the generation of submicron defects on fused silica surface was investigated for the first time from the perspective of secondary particle agglomeration strength of CeO2. The concentration of Ce3+ in CeO2 was characterized by the redshift of the band‐gap energy, and the analysis of material removal rate (MRR) and contact angle of polished fused silica shows that Ce3+ enhances MRR through increasing the silanol group on fused silica. [ABSTRACT FROM AUTHOR]

Certain aspects before and during the fabrication of single‐crystal diamond (SCD) membranes are highlighted, which are decisive to obtain high‐quality membranes with low surface roughness values around 0.2 nm on a small area scale. In addition to the requirements for the starting material, including a high planarity and a moderate surface roughness, the importance of cleaning processes to minimize particles and impurities before and during the structuring is emphasized. With the help of a planarization procedure, consisting of a combination of different Ar/Cl2 recipes with low etch rates, surface defects like grooves due to polishing are minimized and smooth surfaces are acquired. Severe micro‐masking can be prevented by the application of a cyclic Ar/Cl2 + O2 recipe, allowing finally the fabrication of defect‐minimized and planarized SCD membranes in the thickness range between a few microns and a few hundred nanometers. The high quality of the structured SCD membranes is evidenced with a morphological as well as optical characterization via fiber‐based microcavity measurements. [ABSTRACT FROM AUTHOR]

Abrasive waterjet, which is capable of machining all kinds of materials without generating obvious heat and dust, was proposed for treating rail for the first time. With the employment of China's U71Mn heavy rail of 60 kg/m, the fitting method for the cross-section profile of the rail head and the compensation cutting strategy of abrasive waterjet were proposed. The feasibility of rail surface treatment using abrasive waterjet and the influence of jet pressure and traverse speed on the profile deviation and surface roughness were studied. Moreover, both the macro-morphology and micromorphology of the rail surface before and after abrasive waterjet treatment were analyzed using the scanning electron microscope. Results show that abrasive waterjet could effectively remove the surface defects like pits, rust, and microcracks under the experimental conditions. Jet pressure and traverse speed greatly affect the surface roughness and profile deviation. In addition, the profile deviations and the surface roughness of the rail surface treated by abrasive waterjets could satisfyingly meet the acceptance standard (Chinese TJ/GW170-2021). To be more specific, the rail profile and surface roughness after treating can reach 0.337 mm and 2.691 μm, respectively, at jet pressure of 400 MPa and traverse speed of 200 mm/min. [ABSTRACT FROM AUTHOR]

Electro-spark deposition (ESD) is an effective way to weld non-weldable materials and fabricate coatings. However, severe surface defects such as pores, cracks, and element segregation introduced in the ESD process deteriorate the performance of the material. In this study, WC-10 wt.% Co coatings were prepared with different parameters to investigate the effect of key factors on surface features, which are evaluated by the thickness uniformity of coating, density of pores and cracks, degree of element segregation, and surface roughness. Massive statistical results showed that pulse energy, the number of electro-spark deposition layers, and their interaction mightily affect the coating defects. Quantitative analysis demonstrated that the ultra-low efficiency deposition in the later stage of ESD could effectively repair coating defects. In addition, the evolution of coating defects and the effect of preparation parameters on surface integrity were probed. [ABSTRACT FROM AUTHOR]

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A finite element model of single abrasive grinding was established to analyze the material removal during the grinding process and analyze the surface and subsurface defects of the material after grinding. Using the orthogonal test method to machine the surface of the workpiece with a grinding rod of 2 mm grinding head diameter, and to investigate the influence degree of the machining parameters on the roughness. It was concluded that the grinding depth has the most significant effect on surface roughness, followed by the spindle speed and the feed speed, and the minimum roughness of the ground surface obtained was 0.066 µm. The rough surface was simulated by the digital filtering method based on fast Fourier transform (FFT), and the morphological characteristics of the rough surface at Ra = 0.116 µm were described, and the simulated surface was consistent with the detected surface. The laser scanning confocal microscope (LSCM) and scanning electron microscope (SEM) were used for inspection, and the analysis showed that the main removal forms of the enhanced particles were broken, fractured, and pulled out. The surface defects were cracks, pits, and burrs, and the subsurface damages were voids, cracks, and pits. [ABSTRACT FROM AUTHOR]

The L/F DC01 steel plate imported through the company Acinox Comercial, is usually stored in the open, thus promoting the appearance of corrosion phenomena. Using gravimetric methods, the corrosion behavior of this steel is determined in natural urban-industrial and marine-industrial environments, and in accelerated climatic tests, in order to determine the effects due to loss of thickness and variation in apparent surface roughness. A 23 factorial experimental design was carried out to evaluate the incidence of time, temperature and relative humidity on performance variables such as surface roughness and corrosion rate. The results show the influence of exposure time and relative humidity on the corrosion rate, and their interaction on surface roughness. Using optical microscopy techniques, the existence of defects on the exposed surface is corroborated. Corrosion rate graphs are obtained as a function of exposure time in different environments. It is evident that the evaluated steel suffers corrosion in exposed environments and during storage, where corrosion progresses continuously for 25 days. [ABSTRACT FROM AUTHOR]