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This work aims to provide a comprehensive understanding of the structural impact of micro-texture on the properties of bearing capacity and friction coefficient through numerical simulation and theoretical calculation. Compared to the traditional optimization method of single-factor analysis (SFA) and orthogonal experiment, the multivariate linear regression (MLA) algorithm can optimize the structure parameters of the micro-texture within a wider range and analyze the coupling effect of the parameters. Therefore, in this work, micro-textures with varying texture size, area ratio, depth, and geometry were designed, and their impact on the bearing capacity and friction coefficient was investigated using SFA and MLA algorithms. Both methods obtained the optimal structures, and their properties were compared. It was found that the MLA algorithm can further improve the friction coefficient based on the SFA results. The optimal friction coefficient of 0.070409 can be obtained using the SFA method with a size of 500 µm, an area ratio of 40%, a depth of 5 µm, and a geometry of the slit, having a 10.7% reduction compared with the texture-free surface. In comparison, the friction coefficient can be further reduced to 0.067844 by the MLA algorithm under the parameters of size of 600 µm, area ratio of 50%, depth of 9 µm, and geometry of the slit. The final optimal micro-texture surface shows a 15.6% reduction in the friction coefficient compared to the texture-free surfaces and a 4.9% reduction compared to the optimal surfaces obtained by SFA. [ABSTRACT FROM AUTHOR]

Pavement skid resistance plays a crucial role in ensuring road safety and avoiding accidents. In the past, the laboratory evaluation of the skid resistance was carried out by studying only the coarse aggregates of the wearing course. To overcome this drawback, the Wehner-Schulze (WS) machine was developed in Germany in the 1960s. This equipment, composed of a polishing unit and a measuring unit, has great potential in predicting pavement skid resistance and its evolution over time, but is still little known in the pavement community (especially outside Europe). For these reasons, there is a need of a comprehensive review of the existing technical-scientific literature concerning the use of the WS machine. Specifically, this paper focuses on the main factors affecting the skid resistance in WS tests, the correlation of WS data with other laboratory test methods and with field skid resistance/polishing, and the available prediction models that have been validated through WS measurements. The critical analysis of the existing literature highlights that it is possible to correlate WS data with typical skid resistance field measurements as well as WS polishing with traffic polishing, but further efforts are needed in this regard. Future work should focus especially on open-graded mixtures and innovative asphalt mixtures (e.g., containing recycled materials and additives). From the perspective of pavement management, based on a theoretical background, the WS test results could be used as starting point for simplified prediction models of the in-situ skid resistance. [ABSTRACT FROM AUTHOR]

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper aims to provide a method for improving the tribological properties of 316L stainless steels in seawater. During the experimental process, laser texturing technology was used to create biomimetic micro-textures inspired by turtle shell patterns on the 316L stainless steel surfaces. Then, CrAlSiN coating was deposited on the textured surface using the physical vapor deposition (PVD) technique, allowing us to study the frictional properties of the samples in both atmospheric and seawater environments. The results showed that, compared to polished 316L stainless steel, the specimens treated with micro-texture and CrAlSiN coating exhibited a reduction in wear rate by 52.1% and 71.8% under atmospheric and seawater friction conditions, respectively. Under atmospheric friction conditions, the micro-textures had a limited effect on reducing the friction of the 316L stainless steel substrate. However, the CrAlSiN coating, due to its excellent mechanical properties, significantly improved the wear resistance of the 316L stainless steel. Under seawater friction conditions, the continuous CrAlSiN coating played a role in reducing 316L stainless steel wear and seawater corrosion. At the same time, the micro-textures acted as reservoirs for wear debris and seawater, forming a more stable seawater lubricating film and reducing the friction coefficient. Therefore, the synergistic effect of the CrAlSiN coating and biomimetic micro-textures demonstrated remarkable improvement in the tribological performance of 316L stainless steel in seawater environments. [ABSTRACT FROM AUTHOR]

In this article, the yield strength, tensile strength, and the microstructure of the wrought aluminium alloy 7449 rolled thick plate have been studied through thickness under different temper conditions. For all heat treatments, it has been proven that the yield strength and tensile strength values increase from the surface to the centre. The largest difference between the centre and the surface, in both properties, occurs in the case of a sample aged at room temperature for 120 h (TTA temper). The sample artificially aged at 120 °C for 24 h (TTB temper) shows the best strength-gradient relationship of the tensile properties through the thickness. Metallographic characterisation carried out by optical and scanning electron microscopy shows much finer elongated grains in the region near the surface of the plate than in the centre, with incipient recrystallisation in the area near the surface. In addition, electron backscattered diffraction technique, used for micro-texture analysis, has proven the presence of a gradient of crystallography texture in the plate. This explains the yield strength gradient, since the rate of change of the Taylor factor through thickness correlates with the rate of the change of yield strength in the longitudinal direction for the samples studied. [ABSTRACT FROM AUTHOR]

Pavement skid resistance plays a crucial role in ensuring road safety and avoiding accidents. In the past, the laboratory evaluation of the skid resistance was carried out by studying only the coarse aggregates of the wearing course. To overcome this drawback, the Wehner-Schulze (WS) machine was developed in Germany in the 1960s. This equipment, composed of a polishing unit and a measuring unit, has great potential in predicting pavement skid resistance and its evolution over time, but is still little known in the pavement community (especially outside Europe). For these reasons, there is a need of a comprehensive review of the existing technical-scientific literature concerning the use of the WS machine. Specifically, this paper focuses on the main factors affecting the skid resistance in WS tests, the correlation of WS data with other laboratory test methods and with field skid resistance/polishing, and the available prediction models that have been validated through WS measurements. The critical analysis of the existing literature highlights that it is possible to correlate WS data with typical skid resistance field measurements as well as WS polishing with traffic polishing, but further efforts are needed in this regard. Future work should focus especially on open-graded mixtures and innovative asphalt mixtures (e.g., containing recycled materials and additives). From the perspective of pavement management, based on a theoretical background, the WS test results could be used as starting point for simplified prediction models of the in-situ skid resistance.

In modern industrial production, noise can reflect the cutting state of the workpiece and tool to a certain extent, and the noise collection method cannot interfere with the complex processing environment. To further improve the cutting performance of coated cemented carbide micro-textured tools, this paper builds a friction and wear test platform for micro-textured cemented carbide pins with AlSiTiN-AlCrN coating and titanium alloy discs. Based on the test noise signal, the relationship between friction and wear and the noise of the workpiece was studied by the Hilbert–Huang transform (HHT). Through the change of noise in different periods, the micro-texture and coating life of cemented carbide pin under other processing parameters were analyzed. Based on the influence of the interaction between processing parameters and micro-texture diameter on the test results, the test parameters were optimized. The results show that the change of noise signal during the test presents a "V" curve with the grinding process, which mainly affects the noise through the shift of pin-disc friction form and the anti-wear effect of micro-texture. The interaction mainly affects the test results by affecting the micro-texture diameter, laser energy concentration, and the roughness of the inner wall of the pit. The optimized micro-texture geometry and preparation parameters are as follows: scanning times is 8, micro-texture diameter is 50 μm, scanning speed is 1500 mm/s, micro-texture spacing is 170 μm, and laser power is 40 W. The research content of this paper provides a reference for improving the surface properties of cemented carbide. [ABSTRACT FROM AUTHOR]

In bone-milling surgical procedures, the intense friction between the tool and bone material often results in high cutting temperatures, leading to the thermal necrosis of bone cells. This paper aims to investigate the effect of micro-texture on the tribological properties of YG8 cemented carbide in contact with bone. The main objective is to guide the design of tool surface microstructures to reduce frictional heat generation. To minimize experimental consumables and save time, numerical simulations are first conducted to determine the optimal machining depth for the texture. Subsequently, micro-textures with different shapes and pitches are prepared on the surface of YG8 cemented carbide. These textured samples are paired with bovine cortical bone pins featuring various bone unit arrangements, and friction and wear tests are conducted under physiological saline lubrication. The experimental results indicate that the appropriate shape and pitch of the micro-texture can minimize the coefficient of friction. The parallel arrangement of bone units exhibits a lower coefficient of friction compared to the vertical arrangement. This study holds significant implications for the design and fabrication of future micro-texture milling cutters. [ABSTRACT FROM AUTHOR]

Through in-depth analysis of the experimental details and forming patterns of the nanosecond laser ablation polycrystalline diamond (PCD) textured tool processing system, this study explores the microscopic morphology and dimensions of micro-pits texture on the surface of PCD tools influenced by defocus amount, laser power, and pulse frequency. Experimental results indicate that the micro-pit textures generated under different parameters exhibit diversity, including rounded structure, fragments, recast layers, and heat-affected zones. The diameter and depth of micro-pits are comprehensively affected by defocus amount, laser power, and pulse frequency, showing complex patterns. After a thorough analysis of the effects of each parameter on the texture morphology, an artificial neural network (ANN) model is introduced for the prediction of micro-pit dimensions. Through model training and optimization, accurate predictions of micro-pit diameter and depth are obtained. In comparison to traditional regression models, the ANN model demonstrates outstanding predictive performance, validating its applicability in complex machining processes. This study not only provides a profound understanding of the processing patterns of PCD textured tools but also offers an effective predictive model for the optimization and control of similar future machining processes. [ABSTRACT FROM AUTHOR]

In this work, the effect of laser shock peening (LSP) on the electrochemical behavior of HSLA steel (ASTM A 588 Grade D) in 3.5 wt.% NaCl solution was investigated. The microstructural evolution, micro-texture development, surface roughness, residual stress development, microhardness, dislocation density, potentiodynamic polarization, and electrochemical impedance spectroscopy were studied in depth. The corroded surfaces (with and without LSP) were characterized using scanning electron microscopy and Raman spectroscopy for understanding the nature of the passive film formation and its stability. The results revealed that LSP treatment marginally refines the near-surface microstructure from 9.1 to 7.4 μm and generated high compressive residual stress (CRS) of about 500 MPa on the top surface; such variation happened due to severe plastic deformation during LSP. The micro-texture analyses of the laser-peened specimens (on the surface) revealed that {011} <111> texture components were significantly increased while the γ-fiber weakened after laser-peening. Dislocation density was obtained ~ 9.266 × 1012 on the unpeened and ~ 1.158 × 1013 on the laser-peened surfaces, indicating that higher pressure shock waves plastically deformed the top layer of the peened specimen. The corrosion studies indicated about 4 times improvement in the corrosion resistance of the peened specimens—the combined effects of LSP-induced gradient CRS and refined microstructure improved the corrosion resistance. The EDS and Raman spectroscopy results demonstrated the persistence of a compact and continuous passive oxide film/layer, primarily made of Fe2O3, on the surface of the laser-peened specimens. [ABSTRACT FROM AUTHOR]

In order to further reduce the height of burrs on the surface of the workpiece when milling titanium alloy with ball-end milling cutters and optimize the quality of the workpiece, this article takes the mesoscopic geometric feature of ball-end milling cutters as the research object and establishes the theoretical relationship between the mesoscopic geometric feature parameters and the height of titanium alloy burrs during milling. A milling test platform was built to explore the influence of micro-texture, blunt edge single factor, and their interaction with cutting parameters on the force-thermal characteristics and workpiece burr in the milling process. The influence mechanism was revealed, and the prediction model was established. The results show that the ball-end milling cutter with mesoscopic geometric features was able to suppress burrs, and the burr height was reduced by 21% compared with the non-textured milling cutter. The micro-texture reduced the contact area and improved the heat dissipation conditions, thereby reducing the force-thermal characteristics and thus inhibiting the formation of some burrs. The blunt edge can disperse the stress, diffuse the local heat in the tool–chip contact area, and reduce the burr height. In the interaction test considering cutting parameters, the interaction between R and ap was significant. The optimized parameters based on the simulated annealing algorithm were as follows: the radius of the blunt edge was 33.242 μm, the distance between the texture and the edge was 114.621 μm, the texture diameter was 59.820 μm, the texture spacing L1 was 131.410 μm, the cutting depth ap was 0.310 mm, the cutting speed V was 140.019 mm/min, and the feed f was 60 μm/z. This provides a basis for the study of strengthening the tool to suppress burr size. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to solve the problems of serious tool wear and poor processing quality in the process of titanium alloy processing, cutting-edge dulling and surface texturing technology are applied to improve the service performance of cutting tools. Designing multiple density micro-textured tool according to the friction form of the tool-chip contact area is an essential factor in ensuring the cutting performance of tool. In this paper, firstly, the influence of laser parameters on the temperature field and stress field of the material is analyzed, and the optimized laser parameters are obtained. Secondly, the experimental milling platform of multiple distribution density micro-texture ball-end milling cutter under the action of cutting edge is built. The influence of micro-texture and cutting-edge parameters on tool milling performance and work-piece quality is analyzed, and the mechanism is revealed. Finally, the parameters are optimized based on the simulated annealing algorithm. The results show that the main parameters affecting the milling force, tool wear, and work-piece surface roughness are the edge radius and the micro-texture diameter of the stickiness area. It has opened up new ideas for the efficient cutting of titanium alloy. [ABSTRACT FROM AUTHOR]

Titanium alloy material has physical properties such as low thermal conductivity, high hardness, and surface resilience, which are prone to problems such as large milling force, low machining efficiency, and poor surface quality in processed products during dry milling. This document details our process of isolating micro-textures from biological structures, applying them to cutting tool surfaces to create micro-texture milling cutters, and employing this micro-texture technique to reduce friction and prevent wear on these cutters. According to the milling dosage and the installation position between the tool and the workpiece, the effective working area of the cutting edge of the ball-end milling cutter is calculated. At the same time, a self-lubricating cutter was constructed by using a laser to process micro-textures and filling solid lubricant inside the micro-textures. An analysis was conducted to compare the milling efficiency of bionic microtextured cutters in both dry and micro-lubricated environments. It was found that the self-lubricating tool promoted a 3% to 5% decrease in milling force, a reduction in the coefficient of friction, a high surface finish of the machined workpiece, and an alleviation of chip sticking at the edge area. [ABSTRACT FROM AUTHOR]

This article intends to study the influence of micro-texture and Vickers hardness on the Polished Stone Value (PSV) of four types of high friction aggregates (90# Bauxite, 75# Bauxite, Basalt, and Granite) during the long-term polishing process. For this purpose, profile roughness, Vickers hardness, and PSV were tested. The relationship between profile roughness, Vickers hardness, and PSV was analyzed with gray correlation analysis and mathematical fitting. The results show that arithmetic mean roughness (Ra) and maximum height (Rz) influenced PSV significantly while root mean square height (Rq), skewness (Rsk), kurtosis (Rku), and load length ratio (Rmr (c)) had a relatively weak effect. Because of the high correlation with PSV, Ra and Rz were chosen as indicators, and the relationship between variables (Ra, Rz) and PSV was established. There is a good linear relationship between the attenuation rate of Ra and Rz per polishing cycle (K1 and K2) and Vickers hardness. Finally, a model of estimation of the polished stone value of high friction aggregate based on micro-texture and Vickers hardness during the long-term polishing process is developed. Measuring the profile roughness and Vickers hardness to obtain Ra, Rz, and H correlation values and substituting them into the modeling equations in this paper can be used for optimal selection and life estimation of high friction aggregates, which belong to the raw materials, and the optimal selection of high friction aggregates will be helpful for the design of wear-resistant coatings, especially for high friction surface treatments. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the micro-texture and plastic anisotropy of a dual phase steel. A DP800 steel was produced by cold rolling and intercritical annealing of a low carbon steel. Micro-texture analysis on the DP800 steel by means of electron backscatter diffraction revealed that a high orientation density exists along the α and γ fibers. However, the overall texture intensity was not significant. Tensile testing of the DP800 steel at different angles to the rolling direction demonstrated a very low dependency of tensile properties and work hardening behavior to the loading direction. Nevertheless, the r-value showed some directionality with a mean value of 0.851, suggesting a substantial anisotropy for the studied DP800 steel. [ABSTRACT FROM AUTHOR]

In bone-milling surgical procedures, the intense friction between the tool and bone material often results in high cutting temperatures, leading to the thermal necrosis of bone cells. This paper aims to investigate the effect of micro-texture on the tribological properties of YG8 cemented carbide in contact with bone. The main objective is to guide the design of tool surface microstructures to reduce frictional heat generation. To minimize experimental consumables and save time, numerical simulations are first conducted to determine the optimal machining depth for the texture. Subsequently, micro-textures with different shapes and pitches are prepared on the surface of YG8 cemented carbide. These textured samples are paired with bovine cortical bone pins featuring various bone unit arrangements, and friction and wear tests are conducted under physiological saline lubrication. The experimental results indicate that the appropriate shape and pitch of the micro-texture can minimize the coefficient of friction. The parallel arrangement of bone units exhibits a lower coefficient of friction compared to the vertical arrangement. This study holds significant implications for the design and fabrication of future micro-texture milling cutters.

This study aimed to develop a longitudinal ultrasonic-assisted milling system to investigate the machinability of titanium (Ti) Alloy Ti-6Al-4V (TC4). Aiming at reduced milling force and enhanced surface quality, ultrasonic-assisted milling was investigated taking into account the following processing parameters: spindle speed (cutting rate) n, feed per tooth fz, milling depth ap, and ultrasonic amplitude A. A comparison was made with conventional milling. The results of univariate tests demonstrated that the ultrasonic amplitude had the most significant impact on the milling force along the z-axis, resulting in a reduction of 15.48% compared with conventional milling. The range analysis results of multivariate tests demonstrated that ap and fz were the dominant factors influencing the cutting force. The minimum reduction in the milling force in ultrasonic-assisted milling along the x-, y-, and z-axes was 11.77%, 15.52%, and 17.66%, respectively, compared with that in conventional milling. The ultrasonic-assisted milling led to reduced surface roughness and enhanced surface quality; the maximum surface roughness in ultrasonic-assisted milling was 25.93%, 36.36% and 26.32% in terms of n, fz, and ap, respectively. In longitudinal ultrasonic-assisted milling, the periodic "separation-contact" was accompanied by microimpacts, resulting in even smaller intermittent periodic cutting forces. Hence, regular fish scale machining mesh was observed on the processed surface, and the workpiece surface exhibited high cleanness and smoothness. The reasonable configuration of ultrasonic-assisted milling parameters can effectively improve the milling force and surface quality of Ti alloys and accumulate reference data for the subsequent machining process research. [ABSTRACT FROM AUTHOR]

Titanium alloy material has physical properties such as low thermal conductivity, high hardness, and surface resilience, which are prone to problems such as large milling force, low machining efficiency, and poor surface quality in processed products during dry milling. This document details our process of isolating micro-textures from biological structures, applying them to cutting tool surfaces to create micro-texture milling cutters, and employing this micro-texture technique to reduce friction and prevent wear on these cutters. According to the milling dosage and the installation position between the tool and the workpiece, the effective working area of the cutting edge of the ball-end milling cutter is calculated. At the same time, a self-lubricating cutter was constructed by using a laser to process micro-textures and filling solid lubricant inside the micro-textures. An analysis was conducted to compare the milling efficiency of bionic microtextured cutters in both dry and micro-lubricated environments. It was found that the self-lubricating tool promoted a 3% to 5% decrease in milling force, a reduction in the coefficient of friction, a high surface finish of the machined workpiece, and an alleviation of chip sticking at the edge area.

The load capacity of ultrasonic levitation bearing has become an important factor limiting its practical application in engineering, due to which the load capacity is very small compared to that of other gas bearing. In order to obtain greater load capacity, surface texture is introduced into ultrasonic levitation bearing in this study. A theoretical model considering the geometry parameters and mode shape is established to obtain the running performance of surface-textured ultrasonic levitation bearing, which is solved by using eight-point discrete grid finite-difference method. Influence of driving voltage, rotational speed, eccentricity ratio, texture position, and texture size parameters on load capacity is investigated systematically. Previous experimental results were used to verify the feasibility of the proposed model. The results show that positive texture can effectively improve the load capacity of ultrasonic levitation bearing, especially under ultrasonic levitation mode. Research results are instructive for understanding the lubrication mechanism of ultrasonic levitation bearing and further promote the practical application of the bearing in engineering. [ABSTRACT FROM AUTHOR]

At present, for micro-textured tools, the determination of the micro-texture placement area depends on the derivation of the cutting geometric model. The micro-texture distribution form applies geometric methods, and the research methods and accuracy are limited. Therefore, in this paper, the ball-end milling cutter is taken as the research object. Based on fractal theory, the morphology of the tool before and after wear is compared to determine the tool–chip contact area. The uniform-density micro-texture distribution model is established using the uniform distribution point theorem, and the synergistic mechanism of the edge and the micro-texture is revealed. The strength of the micro-textured tool with uniform density under the action of the edge is studied by simulation. Finally, the determination of the tool–chip contact area and the establishment of a uniform-density micro-texture model is realized. It is proved that the synergistic effect of the cutting edge and the micro-texture has a positive effect on the milling behavior of the tool. When comparing the non-edge and non-texture tools with the cutting-edge tools, the maximum strain and stress of the cutting-edge micro-textured tools increased by 12% and 30%, and 30% and 20%, respectively, without affecting the normal use of the tool. This research provides a new method for the design of micro-textured tools. [ABSTRACT FROM AUTHOR]

Laser-induced plasma-assisted ablation (LIPAA) is a promising microfabrication method. In the experiment, a piece of transparent material (quartz) was placed above the absorption material (copper plate). The effects of laser fluence, repetition rate, and scan speed on the results and their mechanism were analyzed. The changes of micro-texture size, copper content, and contact angle (CA) on quartz surface were discussed. The micro-texture height keeps between 2.6 and 3.1 μm when the repetition rate increases to 2.5 MHz. The micro-texture size increased with the laser fluence and decreased with the scan speed. The copper content reached a maximum of 39% at 1.91 MW/cm2 and 2.5 MHz. The quartz surface processing area achieves hydrophobic performance without any post-treatment. The CA reached its optimal value of 146° at 900 mm/s and 2 MHz. There is a correlation between hydrophobicity and micro-texture size. The research results can provide a reference for optimizing the LIPAA parameters of quartz. The studied LIPAA method can potentially be employed for the fast and effective fabrication of hydrophobic surfaces without post-treatment. [ABSTRACT FROM AUTHOR]

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The stress field redistribution at the tool–chip interface of micro-textured tools was examined. The effect of stress field redistribution on the cutting performance was also investigated, including cutting forces, friction characteristics, and chip morphology. The findings have shown that the main cutting forces were reduced by 18% through the decrease of average shear strength and tool–chip contact area. The equivalent average friction coefficient ua deceased from 0.66 to 0.64 with the groove texture width increasing from 80 to 140 μm. The chip deformation coefficient also decreased from 3.4 to 2.77 with the increase of groove texture width, which was mainly attributed to the improvement of friction characteristics at the tool–chip interface. In order to characterize the stress field redistribution at the tool–chip interface, an improved theoretical model of stress field redistribution for micro-textured tool was proposed based on Zorev's assumption. The stress field was assumed as zero in the groove texture zone and had a maximum local stress because of the appearance of derivative cutting. The proposed model was validated by the calculations of normal and friction forces. Combined with the theoretical calculations and experimental findings, the results have shown that with the increase of groove texture width, the decrease of normal and shear stress in the groove texture zone was enlarged. And the increase of normal and shear stress, caused by derivative cutting, was reduced. Then, under the combined effect of groove texture and derivative cutting, the friction characteristics at the tool–chip interface can also be improved. The present findings give more insight in to the stress field redistribution of micro-groove textured tools and the underlying friction mechanisms at tool–chip interface. [ABSTRACT FROM AUTHOR]

It is difficult to machine with high machining efficiency and surface integrity for SiCp/Al composite, especially for those with a high volume fraction of SiC. Here, we present monolayer brazed diamond grinding wheels that contain different micro-textures ablated by pulse laser. The dry grinding characteristics of SiCp/Al composites with 70 vol.% SiC using the wheels with different micro-textures were investigated. The influence of micro-textures on the grinding force, grinding temperature, and surface integrity was examined. The results indicated that micro-textures on diamond grits can induce cleavages and form more micro-cutting edges in grinding of SiCp/Al. The wheel contains both micro-grooves and micro-hole and owns the lowest grinding force, grinding temperature, and surface integrity. The micro-textured wheel produces smaller grinding chips and less fracture, crushing, and pull-out of SiC particle on the ground surface of SiCp/Al composites than other wheels. [ABSTRACT FROM AUTHOR]

The GH4169 superalloy has the characteristics of high strength, strong thermal stability, large specific heat capacity, small thermal conductivity, etc., but it is also a typical hard-to-cut material. When cutting this material with ordinary cutting tools, the cutting force is large, and the cutting temperature is high, which leads to severe tool wear and short service life. In order to improve the performance of tools when cutting GH4169, reduce the cutting temperature, and extend the service life of the tool, micro-textured tools were used to cut GH4169 in spray cooling. The effects of micro-texture morphology and dimensional parameters on cutting temperature were analyzed. Firstly, tools with micro-textures of five different morphologies were designed near the nose on the rake face of the cemented carbide tools. The three-dimensional cutting models of the micro-textured tools with different morphologies were established by using ABAQUS, and a simulation analysis was carried out. Compared with the non-textured tools, the micro-texture morphology with the lowest cutting temperature was selected according to the simulation results of the cutting temperature. Secondly, based on the optimized morphology, tools with micro-textures of different size parameters were designed. When cutting GH4169, the cutting temperature of the tools was simulated and analyzed, and the size parameters of the micro-textured tools with the lowest cutting temperature were selected as well. Finally, the designed micro-textured tools were processed and applied in cutting experiments. The simulation model was verified in the experiments, and the influence of size parameters of micro-textures on the cutting temperature was analyzed. This paper provides a theoretical reference and basis for cutting GH4169 and the design and application of micro-textured tools. [ABSTRACT FROM AUTHOR]

To cope with the constant change of tool–work contact area caused by the constant change of workpiece surface curvature during machining surface, the tool–work contact area is evaluated, and the mathematical model of micro-texture distribution is constructed. The milling simulation is carried out by ABAQUS software. The obtained results show that the tool inclination angle is the main factor affecting the milling force, and the micro-texture diameter is the leading factor influencing the milling temperature. Subsequently, the milling experiment is carried out, and a reasonably good agreement between the observed data and the simulation results is reported. The artificial fish swarm algorithm is also exploited to optimize the parameters. [ABSTRACT FROM AUTHOR]

A hermetic reciprocating compressor is one of the most critical parts for the energy efficiency of a household refrigerator. Piston-cylinder contact in the hermetic compressor accounts for most of the energy loss. The tribological performance of the piston-cylinder pair can be enhanced by introducing micro-texturing on the piston surface. In this research, an experimental study is presented to tribologically assess the effect of the micro-textured piston on the performance of the hermetically sealed reciprocating compressor. The micro-texture on the piston surface was prepared by the laser surface texturing method. Four different micro-textures were studied: radial micro-grooves, axial micro-grooves, mesh micro-grooves, and micro-dimples. The textures' size, shape, and depth were studied using scanning electron microscopy (SEM) and white light interferometry (WLI) techniques. The results were compared with the non-textured piston compressor. It was found that the radial, axial, and mesh micro-grooves pistons have a negative effect on the coefficient of performance of the hermetic reciprocating compressor. However, the piston with the micro-dimples texture increased the compressor's coefficient of performance by 1%. Refrigerant leakage from the piston-cylinder clearance was also investigated and it was observed that micro-dimples on the piston surface decrease the refrigerant leakage by 35% due to the presence of a continuous oil film between piston and cylinder. The compressor's cooling capacity (Qc) was observed to be increased by 1 W in the case of a micro-dimpled piston. [ABSTRACT FROM AUTHOR]

The surface integrity of machined workpiece is an important index to evaluate the service performance of parts. In order to improve the service performance and machining efficiency of titanium alloy, the concept of variable distribution density micro-textured ball end milling cutter is proposed based on texture effect. Firstly, based on the ball end milling model of titanium alloy, a variable density micro-texture model is established in the chip contact region. Secondly, a milling titanium alloy test platform was built to reveal the change law and mechanism of micro-texture parameters on the machined surface integrity. Finally, based on the hierarchical structure weight method and fuzzy comprehensive evaluation theory, the integrity of the machined surface is comprehensively evaluated and the micro-texture parameters are optimized. The results show that the variable distribution density micro-texture has a positive effect on improving the machining quality of titanium alloy. The micro-texture in the bonding zone can reduce the tool-chip contact area, improve the friction state, increase the heat dissipation area, and reduce the plastic deformation of titanium alloy. The micro-texture in the slip zone can improve the chip curl and promote the stability of the system. In addition, reasonable micro-texture parameters can obtain better surface quality of the workpiece. [ABSTRACT FROM AUTHOR]

The machining of titanium alloy can lead to serious tool wear, with this resulting in a lack of milling system stability and chatter. This paper looks at the relationship between milling stability and the use of micro-texturing on cutter surfaces, which aims to reduce tool wear. A stability lobe diagram is first drawn that is based on a dynamic model of the milling of titanium alloy by a ball-end milling cutter. This provides the cutting parameters for a stable domain. A micro-texture distribution model is then established for different cutting depths and the influence of micro-texture parameters on the milling performance of cutting tools according to various cutting parameters studied. The parameters are then optimized using an artificial bee colony algorithm, with the milling force, machined surface quality, and tool wear being adopted as the principal evaluation indicators. This provides a theoretical basis for the future selection of optimal cutting and micro-texture parameters. [ABSTRACT FROM AUTHOR]

The rotating ultrasonic-assisted grinding (RUAG) experiment of the conical grinding wheel generated the intermittent pit-shaped micro-texture on the surface of the workpiece, reducing thermal damage and improving the lubrication characteristics compared with conventional grinding (CG). To further optimize the surface properties, this paper studied the formation mechanism of micro-texture. This study used as basis the theory that micro-debris volume equals the macroscopic material removal one to establish the mathematical equation of grinding depth. Thereafter, formulas of micro-texture feature parameters, including pit length, pit depth, and texture spacing were deduced. The solved microscopic grinding depth was alternatingly positive and negative, indicating that the alternating separation between the grinding grain and workpiece caused intermittent pits in the grinding. Through response surface analysis (RSA), this paper analyzed the relationships among macroscopic grinding depth, micro-texture feature parameters, and machining parameters (i.e., amplitude, feed rate, and rotational speed). Single-factor experiments of machining parameters, with finite element simulation and experiment methods, were performed to verify the theoretical micro-texture features. The simulated program formed three-dimensional surfaces with micro-textures. Their measurement results were consistent with the theoretical ones. Experimental results proved that the range of pit length covers the theoretical ones, further verifying the accuracy of the grinding depth model. For this grinding wheel, the 8–10 μm amplitude was optimal for better roughness, lubrication, and thermal damage. Roughness was improved when increasing the rotational speed or reducing the feed rate based on the experiment. If the rotational speed and feed rate exceed the limiting values, then continuous grinding will break down the abrasive grains and even damage the cubic boron nitride (CBN) coating. Experimental results likewise showed that the pit shape was closely related to the surface properties, which deserves further investigation. [ABSTRACT FROM AUTHOR]

Placing micro-textures on a tool surface can play an anti-wear and friction-reducing role and capture impurities and improve the tool-chip friction state, thus improving the cutting performance of the tool and the quality of the workpiece. To ensure the processing quality in the micro-texture-coated tool-cutting process, the process parameters and micro-texture parameters are limited to smaller parameters, which reduces the processing efficiency and increases the cost. Aiming at this problem, this paper designs orthogonal experiments of the cutting process and micro-texture parameters, builds an experimental platform for milling titanium alloy with a micro-texture-coated ball-end milling cutter, analyzes the influence of cutting parameters on tool milling performance and workpiece quality, establishes a high fitting prediction model, and optimizes parameters. The results show that the cutting parameters significantly affect the milling force, tool wear, and workpiece surface roughness, which are in the first response level, and the micro-texture parameters, which are in the second response level. It is proven that micro-texture has anti-wear and anti-friction effects, and it is found that micro-texture parameters affect the evaluation index by changing the distribution state of the micro-texture. It is found that the multiple linear regression model fits better. Parameter optimization results are: v = 159.4232 (m/min), ap = 0.211 (mm), f = 0.06 (mm/r), micro-pit diameter D = 62.3429 (μm), distance from blade L = 121.5184 (μm), and micro-pit spacing L1 = 235.6443 (μm). It provides some guidance for the selection of micro-texture parameters and cutting parameters on a micro-texture-coated tool. [ABSTRACT FROM AUTHOR]

Under intermittent milling, rapid temperature changes form thermal stress, and if the thermal stress is too large, cracks will occur inside the tool, and at the same time, the strength will drop sharply, which will eventually lead to tool fatigue failure. Thermal shock corresponds to the occurrence of crack propagation. For the effect of thermal shock on carbide ball end milling cutters, first, the quench-strength method was used to explore the effect of residual flexural strength of specimens with different micro-texture parameters on thermal shock resistance. Then, by combining the tool milling temperature test and thermal coupling simulation, the changes of different micro-texture parameters on the thermal stress of the tool were explored to reveal the effect of thermal stress on thermal shock resistance. [ABSTRACT FROM AUTHOR]

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Surface weaving technology is a technology to prepare geometric arrays with certain arrangement rules on the surface of the material, through surface texture technology modified materials can effectively improve the tribological properties of mechanical parts, and micro-parts materials, which are now more and more widely used in many engineering fields. In recent years, automotive engines are developing in the direction of high power and high speed, and the application of surface texture technology to automotive engines to improve the tribological properties of crankshaft bearing friction subsets to ensure that the engine can maintain good performance under various operating conditions plays an important role. This paper firstly introduces the main achievements of surface texture technology in the field of tribology in recent years; after that, the different aspects such as surface texture shape, depth, area occupancy, and arrangement are classified and reviewed; the friction and wear reduction and anti-wear properties of the modified surface texture of materials are reflected according to the friction coefficient and wear amount. In order to enhance the performance of the engine, the service life of the automotive engine under severe conditions is improved. Finally, the future development trend of surface texture applied to automotive engine crankshaft is prospected and predicted. [ABSTRACT FROM AUTHOR]

Difficult-to-machine materials such as Ni-based superalloy suffer from severe tool wear and poor surface quality; therefore, the cooling mechanism is the key to improving machining performance and reducing the environmental pollution in manufacturing. In the past, plenty of studies verified that the micro-texture on the cutting insert improved the cutting performance under the same cooling condition. The main explanation is that the second generated cracks caused the capillary siphon phenomenon and increased the wettability of the subsurface of the workpiece. In order to investigate the effect of surface wettability differences on the cutting performance of the tool under different micro-textured morphologies, three types of micro-textured CBN tools with pit, linear, and sinusoidal morphologies were fabricated by laser machining technology. Through cutting experiments on Inconel 718 Ni-based superalloy, the cutting force, tool wear, and machined surface roughness of different micro-textured tools were compared and analyzed. The relationship between cutting performance and wettability of different shaped micro-texture was obtained by measuring the contact angle using PT-705B optical angular contact meter. The experimental results show that the presence of surface micro-textures enhances the surface wettability of the tool. It effectively reduces the cutting force and slows down the rake face's wear and the machined part's surface roughness. Compared with other morphologies, sinusoidal micro-textured tools show the best cutting performance. Among the four morphologies of micro-textured tools, cutting performance improvement increases with surface wettability. More generally, these primary findings are consistent with research showing that wettability is critical in micro-texture generation for high-performance machining. The conclusion is very much the key component in future attempts to overcome the assumption of the capillary siphon phenomenon on the subsurface of the workpiece. [ABSTRACT FROM AUTHOR]

A surface modification method was proposed to boost tribological properties of near β-type biomedical titanium alloy Ti3Zr2Sn3Mo25Nb (TLM) by synergistic application of micro-texture and copper coating. In calf serum, the friction coefficient on the TLM surface decreased by approximately 17 % when the micro-texture density was 15 %. Furthermore, the texture-free modified TLM surface exhibited reduced friction coefficients under various loads, with a maximum decrease of nearly 30 %. Additionally, the wear mass and wear rate of TLM surface were as low as 1.97 times and 2.34 times of commercial Ti6Al4V alloy when combining micro-texture with copper coating, respectively. The anti-friction mechanism can be attributed to enhanced load-bearing capacity due to micro-texture and the self-lubricating effect by copper coating. Importantly, introducing copper coating on micro-textured surface will catalyze protein denaturation to generate graphite-like carbon films during friction with an anti-friction property, meanwhile, exhibited significant antibacterial activity, with the antibacterial rate of 99.41 % and 94.70 % against Staphylococcus aureus and Escherichia coli, effectively improving postoperative infections. [ABSTRACT FROM AUTHOR]

In this study, the impact of four linear speeds (75, 95, 115, and 135 mm/min) during fast-multiple rotation rolling (FMRR) on the A390 coating applied via friction surfacing (FS) on the AA1050 substrate was investigated. The microstructure, mechanical properties, and wear resistance were examined using optical microscopy, scanning electron microscopy, electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), nanoindentation tests, microhardness tests, and pin-on-disc tests. Results showed that as the linear speed increased to 135 mm/min, the FMRR-treated layer became 48.6 % thinner. At a linear speed of 135 mm/min, the grain size reduced to 1.24 ± 0.15 μm, and the sizes of Al 2 Cu and Si particles decreased to 0.51 ± 0.02 μm and 3.45 ± 0.11 μm, respectively. The nano-hardness and Young's modulus increased to 9.11 GPa and 218.9 GPa, respectively. Moreover, the wear rate decreased by 43.53 % compared to the consumable rod and by 65.96 % compared to the AA1050 substrate at a linear speed of 135 mm/min. EBSD results indicated the presence of recrystallization and shear texture components in the FMRR-treated layer. TEM analysis confirmed the presence of nanometer-sized Si particles (<10 nm) and grains (100–500 nm) in the FMRR-processed layer. • The effect of fast multiple rotation rolling (FMRR) process on friction surfaced Al Si Cu alloy were investigated. • As linear speed of FMRR process increased to 135 mm/min, the FMRR processed layer became 48.6 % thinner. • EBSD results indicated the presence of recrystallization and shear texture components in the FMRR processed layer. [ABSTRACT FROM AUTHOR]

The micro-texture of aggregates plays a very important role in anti-skid performance of asphalt pavement. Three kinds of aggregates, limestone, basalt and sandstone, were used to prepare asphalt mixture to study the evolution law of micro-texture of aggregates under long-term wear. One Third Scaled Model Mobile Load Simulator (MMLS) was used to conduct wear tests on asphalt mixtures under two working conditions: drying and water immersion. Laser confocal scanning microscopy (LCSM) was used to test and analyze the micro-texture evolution of the original aggregate, mixed aggregate, and accelerated loaded aggregate surfaces. The mechanism of texture evolution was analyzed based on the mineral composition, Vickers hardness, and micro-structure of the aggregate. The results show that wear can lead to varying degrees of polishing of the aggregate micro-texture, with limestone>basalt>sandstone, and the drying condition is more severe than the water immersion condition. The wear degree of the texture is closely related to the mineral composition and hardness of the aggregate. The more complex the mineral composition, the greater the hardness and hardness dispersion, the less likely the texture will be polished. The micro-texture indexes Ra and Rq have the highest correlation with anti-skid performance, and the relationship between them is obtained by fitting. Scanning electron microscopy (SEM) shows that the fine particles in sandstone are easy to fall off, which is conducive to the regeneration of texture, and is also the internal reason for its best anti-skid durability. • The long-term skid resistance of asphalt mixture prepared by three different aggregates under drying and immersion was studied based on MMLS. • The micro-texture evolution of aggregate in asphalt mixture under drying and immersion was studied based on MMLS. • The wear mechanism of aggregate micro-texture was studied from mineral composition, Vickers hardness and micro-structure. [ABSTRACT FROM AUTHOR]

The Ti6Al4V structures in aircraft and biomedical industries are usually exposed to quasi-static loads. Therefore, understanding the quasi-static behaviour of this alloy manufactured by an additive manufacturing process is paramount. This paper documents an investigation of the quasi-static mechanical properties of various microstructures of heat-treated Ti6Al4V(ELI) parts manufactured by laser powder bed fusion (LPBF). The effects of different quasi-static strain rates on different microstructures of these samples and their strain hardening are also presented. The test samples were produced using an EOSINT M280 direct metal laser sintering (DMLS) machine and, thereafter, subdivided into three major groups, namely samples C, D and E, for high-temperature annealing at different heat treatment strategies. A universal hydraulic testing machine (UTM) was used to carry out tests at strain rates of 0.001 s−1, 0.005 s−1 and 0.1 s−1. The three forms of LPBF Ti6Al4V(ELI) were found to be sensitive to quasi-static strain rate, whereby values of yield and flow stresses in each form of alloy increased with increasing strain rate. The order of the strength at each strain rate from the highest to the lowest was found to be samples C, D and E. The effects of strain rate on flow hardening were found to be significant in samples C and insignificant in samples D and E. [ABSTRACT FROM AUTHOR]

Road pavements are exposed to traffic loading and external deterioration agents which both can compromise tire-pavement interactions, posing a threat to road safety. The surface wear generates crushed pavement materials or tire rubber wear particles which, combined with other contaminants, negatively impact the environment. In fact, these particles may remain on the road surface; adhere to tires; become airborne; or drain by rainfall to roadsides, waterways, lakes, and even open oceans. Therefore, the presence of road contaminants on road infrastructure pavements is a concern for both road safety and the environment. Although the condition of pavement, traffic intensity, airborne dust emissions, and roadside environments are significantly monitored by road practitioners, especially in urban areas, there is still a need to better evaluate the pollutants remaining on road surfaces. It is known that particles smaller than 40 μm can be trapped within micro-asperities and remain on road surfaces, while particles of larger sizes can be transported by rainfall. However, it is difficult to mobilize particles with sizes larger than 105 μm by storm water runoffs, which tend to remain on road surfaces. Hence, not only rainfall characteristics are responsible of particle's kinetics, but also particle's size and road surface roughness are important. Therefore, this paper presents an overview of road safety and environmental concerns around contaminants, highlighting the importance of the road surface characteristics in their behavior. Finally, the current methods to measure road surface characteristics and their application for environmental and safety issues are discussed. [ABSTRACT FROM AUTHOR]

The continuous optimization of processing technology and evaluation methods is an important way to achieve high processing quality and processing efficiency for difficult-to-process materials. To solve the problem of frequent defects in the slot, the ultrasonic vibration-assisted slot-milling (UVASM) technology was developed for processing titanium alloy. Simultaneously, comparative experiments were carried out between UVASM and conventional slot milling (CSM), in terms of surface features of slot bottom and slot sidewall, cutting force, tool trajectory, chip morphology, and micro-hardness. The results show that uniform vibration micro-texture could significantly improve surface topography of slot bottom in UVASM, while numerous tool feed trajectories and observable machining defects detract from the surface quality in CSM. The UVASM can greatly reduce material spalling and edge breakage, thereby maintaining a smooth and regular edge profile of the slot sidewall. The tool tip trajectories of the two machining methods are highly corresponding to the machining textures of the slot sidewall surface. There is a high-frequency and small-amplitude force fluctuation signal on the axial force waveform in UVASM, which can reduce the instantaneous maximum milling force and milling force in the stable stage by 8.7 and 12.2%, respectively. The UVASM has a better chip breaking effect and surface anti-scratch effect, and the UVASM can obtain higher surface micro-hardness and deeper plastic deformation layer than those CSM. In summary, the multi-dimensional evaluation of slot processing status has been completed, and the processing quality of the slot has been improved. [ABSTRACT FROM AUTHOR]

Although axial ultrasonic vibration-assisted milling (AUVAM) is promising for rapid and economical fabrication of 3D micro-texture on various surfaces, it has been a challenge to obtain micro-texture with small feature size and large height simultaneously. The mechanism and major influence factors for the formation of micro-texture by this method were explored in this study. It was found that the generation of micro-texture was mainly caused by cutting and extrusion from the flank face of the milling tool under ultrasonic vibration. Therefore, a novel 3D tool model that considered the relief angle, end cutting edge angle and the blade profile was established in simulation analysis. The good agreement between simulation and experimental results demonstrated that the influence of the flank face on the micro-texture was mainly attributed to the relief angle of the milling tool. It was the first time to report that both the height and the profile shape of the micro-texture unit were affected by the overlap and extrusion between the flank surface and the micro-texture. But this influence diminished with the increase of spindle speed. 3D sinusoid-shaped micro-texture with minimum width of 20 μm and height of 2 μm (fully reproduced the ultrasonic amplitude) was realized with the relief angle of 40° and spindle speed of 4000 rpm. Other typical textures of weave, shell, scale and corrugation were also presented to show the effective regulation of texture patterns in AUVAM. This work provides both theoretical and practical basis for such a low-cost, efficient and controllable 3D micro-texture preparation method. [ABSTRACT FROM AUTHOR]

High strength steel sheets of thinner sections are being widely adopted in automotive industries for lightweighting purposes. However, dent resistance of steel sheets reduces with its thickness but increases with its surface yield strength. In this work, we explore the possibility of improving the strength of a sheet metal surface by a micro-texturing process with the aid of finite element simulations. Micro-texturing is expected to increase the strength of the surface because of the inherent size effect of the material and consequently improve the dent resistance. The mechanical responses of such a micro-texture, consisting of an array of rectangular micro-features, are studied for different loading conditions. A higher order strain gradient plasticity theory is employed to analyze the size effect of the micro-texture, under a small strain 2D finite element framework. The influence of the different geometrical features of the micro-texture and the length scale parameter of the material on the mechanical response, are investigated and the implications of these results on the dent resistance are discussed. [ABSTRACT FROM AUTHOR]

The surface properties of alloys can be improved by coating their surfaces and adding a micro-texture. The effect on the surface properties of alloy composite coatings of adding a textured surface has not been addressed in previous studies. In this study, a micro-texture was added to the surface of a WC+Co alloy AlCrN/AlTiSiN composite coating. The influence of the micro-texture's geometric parameters on the surface properties of the composite coating and its lifespan were studied in detail. First, the surface hardness and phases of various micro-textured composite coatings were analyzed to explore the effect of different micro-texture parameters on the surface properties. Then, a friction and wear test was conducted to establish a model that can predict the lifespan of a micro-texture and the influence of different micro-texture parameters on the surface friction of the composite coating. After that, the wear pattern of the composite coating and the relative action of the micro-texture were analyzed on the basis of the visible wear morphology. The results show that using a laser to add a micro-texture to the surface of a composite coating creates a hardened layer that increases the coating's surface hardness. Analysis of the surface phases of the composite coating showed that there are three principal types of grain on the surface, namely WC, CrN and TiN, with WC having the largest grain size. The main kind of wear on the surface of the composite coating was found to be abrasive wear, which can be reduced by the addition of a micro-texture. [ABSTRACT FROM AUTHOR]

The characteristics of dynamic recrystallization (DRX) of a CoCrFeMnNi high–entropy alloy (HEA) was investigated via hot compression testing in the temperature range 950–1100 °C and at true strain rates of 10−2 and 10−1 s−1. The discontinuous DRX was found to be the dominant mechanism corroborating the microstructural evolution. The progress of the initiation of DRX was investigated in terms of critical strain/stress required using the Poliak–Jonas analytical criterion. Consequently, a new kinetic model based on Avrami–type function was established for the HEA to predict the DRX fractional recrystallization. It was revealed that the volume fraction of DRX grains increased with increasing strain. In the case of 10−2 s−1, steady–state flow was achieved after the completion of one DRX process cycle resulting in further straining, leading to the occurrence of dynamic restoration processes involving formation of substructures and generation and annihilation of dislocations inside the DRX grains which effectively increased the fraction of partially deformed DRX (substructured) grains. A good agreement between the proposed DRX kinetics model and microstructure observation results validated the accuracy of DRX kinetics model for CoCrFeMnNi HEA. The preferred orientation of the non–recrystallized grains was towards the formation of fiber texture, whereas a random micro–texture is revealed in the recrystallized grains.

This study aimed to develop a longitudinal ultrasonic-assisted milling system to investigate the machinability of titanium (Ti) Alloy Ti-6Al-4V (TC4). Aiming at reduced milling force and enhanced surface quality, ultrasonic-assisted milling was investigated taking into account the following processing parameters: spindle speed (cutting rate) n, feed per tooth fz, milling depth ap, and ultrasonic amplitude A. A comparison was made with conventional milling. The results of univariate tests demonstrated that the ultrasonic amplitude had the most significant impact on the milling force along the z-axis, resulting in a reduction of 15.48% compared with conventional milling. The range analysis results of multivariate tests demonstrated that ap and fz were the dominant factors influencing the cutting force. The minimum reduction in the milling force in ultrasonic-assisted milling along the x-, y-, and z-axes was 11.77%, 15.52%, and 17.66%, respectively, compared with that in conventional milling. The ultrasonic-assisted milling led to reduced surface roughness and enhanced surface quality; the maximum surface roughness in ultrasonic-assisted milling was 25.93%, 36.36% and 26.32% in terms of n, fz, and ap, respectively. In longitudinal ultrasonic-assisted milling, the periodic “separation-contact” was accompanied by microimpacts, resulting in even smaller intermittent periodic cutting forces. Hence, regular fish scale machining mesh was observed on the processed surface, and the workpiece surface exhibited high cleanness and smoothness. The reasonable configuration of ultrasonic-assisted milling parameters can effectively improve the milling force and surface quality of Ti alloys and accumulate reference data for the subsequent machining process research.