Surface Roughness Research Articles

Alumina-enriched sunflower bio-oil in machining of Hastelloy C-276: a fuzzy Mamdani model-aided sustainable manufacturing paradigm

With the increasing emphasis on sustainable manufacturing practices, eco-friendly lubricants have gained significant attention to moderate the friction coefficient at the tool-work interface. In line with this, the contemporary study aimed to examine the viability of Alumina-enriched sunflower bio-oil as a metalworking fluid. Different volume fractions of Alumina nanoparticles (varying from 0 to 1 vol%) were mixed with sunflower bio-oil, and the physical properties, for instance, contact angle and dynamic viscosity, were analyzed to determine the optimal concentration of Alumina. Subsequently, machining experiments were executed on Hastelloy C-276 under various lubricating conditions, including dry cutting, compressed air, sunflower bio-oil, and 0.6 vol% Alumina-sunflower bio-oil. A comparative analysis among these lubricating mediums demonstrated that sunflower bio-oil with a 0.6 vol% Alumina concentration outperformed others, resulting in a significant reduction of surface roughness, and tool wear by 73.31%, and 82.14% respectively when compared to dry machining. Besides, the utilization of 0.6 vol% Alumina-sunflower bio-oil has demonstrated a reduction of 17.86% in total machining cost, along with reductions of 15.44% in energy consumption and carbon emissions, when compared to dry machining. Finally, a Taguchi-designed experiment consisting of sixteen trials was performed in different lubricating conditions, and a Fuzzy-Mamdani model was employed to achieve a sustainable machining environment. The sustainability assessment results indicated that a cutting speed of 75 m/min, feed of 0.05 mm/tooth, depth of cut of 0.15 mm, and the utilization of the 0.6 vol% Alumina-sunflower bio-oil resulted in the most sustainable machining environment, with the highest Multi-Performance Characteristics Index of 0.75.

Effects of surface roughness of a wave plate on the development of diffractive polarization speckle

Effects of surface roughness of a wave plate on the development of diffractive polarization speckle

Asperity interaction induced vibration excitation of cylindrical roller bearings with localized defect

Asperity interaction induced vibration excitation of cylindrical roller bearings with localized defect

Dissolution Behavior of M5 Cladding in Hydrofluoric–Nitric Mixed Acid

M5 cladding has emerged as a prominent fuel cladding material due to its excellent corrosion resistance. The dissolution behavior of M5 cladding is critical in both the initial cleaning stage and the reprocessing of spent fuel cladding. This study investigated the dissolution of M5 cladding in hydrofluoric–nitric (HF-HNO3) mixed acid at varying concentrations. When the HF concentration exceeds 0.5 mol/L, the addition of strong oxidizing HNO3 significantly reduces the dissolution rate. Moreover, HNO3 effectively inhibits the HF-induced corrosion pitting, lowering surface roughness to 0.812 μm at a 1:5 ratio of HF:HNO3. In addition, a surface structural analysis reveals the dissolution mechanism of M5 cladding. The β-Nb precipitated in the mixed acid was oxidized to stable Nb2O5 by HNO3 while the M5 matrix surface was continuously oxidized to ZrO2. This passivation layer inhibits further dissolution, slowing the process and enhancing the uniformity of M5 cladding.

An Investigation on the Performance of the Ultrasonic Atomization-Based Cutting Fluid (uACF) Spray System

Nowadays, due to limited resources and manufacturers desire to keep manufacturing costs at the lowest level, minimum quantity lubrication systems stand out. Ultrasonic atomization-based cutting fluid (uACF) spray system, which is one of the minimum quantity lubrication methods, attracts attention with its low production cost and much lower cutting fluid consumption compared to conventional cooling systems. A limited number of studies have been carried out to demonstrate the performance of this innovative, compact and environmentally friendly system under real cutting conditions. uACF system was compared with spray cooling (SPR), compressed air cooling (AIR) and dry machining (DRY) conditions using similar machining parameters. Cutting speed and feed rate were selected as machining parameters. The effect of the machining parameters on the cutting force (Fc), cutting temperature (Tc), average surface roughness (Ra) and chip shrinkage coefficient (ξ) were compared with other systems. The study concluded that the uACF system can outperform or compete with different cooling methods in all performance outputs with the right choice of cutting parameter combination. In addition, the study also revealed the effects of cutting speed and feed rate levels on performance outputs under different cooling conditions. In the light of the data obtained from the study, it is concluded that the uACF system provides a good performance under real cutting conditions with a low amount of cutting fluid consumption (0.5 ml/min) with low operating cost and has a high utilisation potential.

Comparative analysis of thermally evaporated nanoscale CdS thin film's structural, morphological, optical and nanomechanical properties

CdS nanoscale thin films were deposited on glass substrates at 1, 5 and 10 Å/s deposition rates by thermal evaporation process. The structural, morphological, compositional, optical and nanomechanical properties of CdS thin films were analyzed by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), energy dispersive x-ray (EDX), UV-vis spectrophotometer and nanoindentation. XRD diffractogram indicate that the deposited CdS thin films have hexagonal structure with preferred orientation towards (002) plane and nearly stoichiometric composition. Various crystal structure parameters like lattice constant, crystallite size, defect density, dislocation density, lattice strain, number of crystallite per unit surface, stacking fault were determined. From XRD results, the calculated crystal structure parameters such as the crystallite size, microstrain and defect density were in the range of 20.4-14.7 nm, 7.74-10.62 and 2.3-4.52 × 1011 lines/cm2, at 1, 5 and 10 Å/s deposition rates, respectively .The AFM images indicated that the film's rms surface roughnesses were 2.73 nm, 2.94 nm and 3.18 nm at 1, 5 and 10 Å/s, respectively. The SEM images indicated that the films were uniform, continuous and defect free. The EDX examination revealed that at 1 Å/s deposition rate the film was nearly stoichiometic. The optical band gaps were determined to be in the range of 2.37-2.43 eV. Nanoindentation tests evaluated the hardness, Young's modulus, creep behavior and strain rate of CdS films. Hardness evaluated to be 0.14-1.48 GPa, 0.15-2.46 GPa, and 0.21-2.55 GPa at 1,5 and 10 Å/s deposition rate, respectively for 20-50 µN load. The Young's modulus decreases 1-5 Å/s deposition rate and becomes almost constant 5-10 Å/s deposition rate at 70 µN load. The characterization of CdS thin film recommend it as a favorable window layer in applications like photovoltaic, optoelectronic, thermoelectric and solar cells.

Research on Stability of Removal Function in Figuring Process of Mandrel of X-Ray-Focusing Mirror with Variable Curvature

Over the past 30 years, researchers have developed X-ray-focusing telescopes by employing the principle of total reflection in thin metal films. The Wolter-I focusing mirror with variable-curvature surfaces demands high precision. However, there has been limited investigation into the removal mechanisms for variable-curvature X-ray mandrels, which are crucial for achieving the desired surface roughness and form accuracy, especially in reducing mid-spatial frequency (MSF) errors. It is essential to incorporate flexible control in deterministic small-tool polishing to improve the tool’s adaptability to curvature variations and achieve stable, Gaussian-like tool influence functions (TIFs). In this paper, we introduce a curvature-adaptive prediction model for compliance figuring, based on the Preston hypothesis, using a compliant shaping tool with high slurry absorption and retention capabilities. This model predicts the compliance figuring process of variable-curvature symmetrical mandrels for X-ray grazing incidence mirrors by utilizing planar tool influence functions. Initially, a variable-curvature pressure model was developed to account for the parabolic and hyperbolic optical surfaces’ curvature characteristics. By introducing time-varying removal functions for material removal, the model establishes a variable-curvature factor function, which correlates actual downward pressure with parameters such as contact radius and contact angle, thus linking the variable-curvature surface with a planar reference. Subsequently, through analysis of the residence time distribution across different TIF models, hierarchical filtering, and PSD distribution, real-time correction of the TIFs was achieved to enable customized variable-curvature polishing. Furthermore, by applying a time-varying deconvolution algorithm, multiple rounds of flexible polishing iterations were conducted on the mandrels of a rotationally symmetric variable-curvature optical component, and the experimental results demonstrate a significant improvement in form accuracy, surface quality, and the optical performance of the mirror.

Effect of Mechanical Surface Treatment on Shear Bond Strength of Orthodontic Brackets to 3D Printed and Milled CAD/CAM Provisional Materials: An In Vitro Study

The aim of the study is to assess the impact of mechanical surface treatments on the shear bond strength (SBS) of orthodontic brackets bonded to three-dimensional (3D) printed and milled CAD/CAM provisional materials. Sixty cylindrical samples were fabricated for each provisional material. Samples were treated with one of the following surface treatments: aluminum oxide airborne particle abrasion, diamond bur rotary instrument roughening, and phosphoric acid etching (control). Stainless steel brackets were bonded to the samples, and then SBS was tested using a universal testing machine. SEM and digital microscopy were utilized to examine the bonding interface and the failure modes. Two-way ANOVA, one-way ANOVA, Tukey’s HSD, and independent sample t-tests were used for statistical analysis. Results revealed significant differences in SBS between 3D printed and milled samples and significant differences in SBS among most surface treatments, with rotary instrument roughening resulting in the highest values for 3D printed, while airborne particle abrasion leading for milled samples. Digital microscopy indicated that more adhesive remained on 3D-printed samples. SEM analysis revealed varying surface roughness across treatments. Based on the findings of this study, it can be concluded that different surface treatments improve the bonding of orthodontic brackets to provisional crowns.

Effect of random roughness on Stokes flow

Microscopic irregularity (roughness) of bounding surfaces affects macroscopic dynamics of fluid flows. Its effect on bulk flow is usually quantified empirically by means of a roughness coefficient. A new approach, which treats rough surfaces (e.g. parallel plates) as random fields whose statistical properties can be inferred from measurements, is presented. The mapping of a random flow domain onto its deterministic counterpart, and the subsequent stochastic averaging of the transformed Stokes equations, yield expressions for the effective viscosity and roughness coefficient in terms of the statistical characteristics of the irregular geometry of the boundaries. The analytical nature of the solutions allows one to handle surface roughness characterized by short correlation lengths, a challenging feature for numerical stochastic simulations.

An improved line contact model for elastic–plastic rough surfaces

An improved line contact model for elastic–plastic rough surfaces

Investigation on the Cutting Performance of High‐Speed Dry Milling for 30CrMnSiNi2A Steel

High‐speed dry milling (HSDM) technology is one of the most attractive solutions for improving the cutting performance of difficult‐to‐machine materials. However, the study of HSDM performance for 30CrMnSiNi2A steel has not been reported. In this article, HSDM for 30CrMnSiNi2A steel is investigated using TiN‐coated and AlTiN‐coated tools, focusing on cutting force, vibration, surface roughness, residual stress, and tool wear. The effects of cutting parameters on cutting force and vibration are remarkably similar. At a spindle speed of 7500 r min−1, both cutting force and vibration are minimized. TiN‐coated and AlTiN‐coated tools exhibit distinct performance differences. But, HSDM of 30CrMnSiNi2A steel using TiN‐coated and AlTiN‐coated tools can achieve low surface roughness. The depth of cut significantly affects surface roughness, which is lowest at the depth of cut (0.8 mm). Most of the workpiece surface shows residual compressive stress. The main wear mechanisms for both coated tools are abrasive wear, adhesive wear, and oxidative wear. Furthermore, the AlTiN‐coated tool is more wear resistant on the flank face compared to the TiN‐coated tool. Chipping due to crater wear is the leading cause of tool failure for the AlTiN‐coated tool. Upon various comparisons, the AlTiN‐coated tool is more suitable for HSDM of 30CrMnSiNi2A steel.

Experimental analysis and low-damage machining strategy for composite ultrasonic vibration-assisted grinding of silicon carbide based on DA-MLP-NSGA-II algorithm

At present, because of the lack of ultrasonic composite vibration assisted grinding mechanism, neural network optimization algorithm (NNOA) is used to optimize the processing results. In NNOA, multi-layer perceptron (MLP) neural network model and non-dominated sorting genetic algorithm-II (NSGA-II) are very efficient and accurate methods. In this paper, based on the measurement and analysis of the specific ultrasonic vibration device, the CUVAG experiments on silicon carbide (SiC) ceramic were carried out to investigate the influence of processing parameters on the grinding forces, the ground surface roughness and morphology, and the subsurface damage. Then, the brittle-ductile removal behavior of hard-and-brittle materials could be revealed according to the above analysis. After that, MLP model and NSGA-II were utilized to predict and optimize the processing results in CUVAG. The results show that the grinding forces are basically constant, the surface quality deteriorates, and the subsurface damage increases with increased axial vibration amplitude and workpiece infeed speed, but all fluctuate with enlarged wheel speed, and turns at the inflection point of brittle-ductile transition with increased elliptic vibration amplitude. The fitting goodness R2 of the established MLP neural network prediction model is between 0.94 and 0.975, and the process parameters calculated by the NSGA-II optimization algorithm are verified. With optimized processing parameters, the grinding forces are reduced by about 13 %, the surface roughness is reduced to Ra0.037 μm (by 29 %), and the depth of subsurface damage is reduced by 68 %.

Exploring temperature effects on compatibility in PS‐b‐PI‐b‐PS block copolymer‐based blends through experimental and molecular dynamics simulation approaches

AbstractThe poly(styrene‐block‐isoprene‐block‐styrene) (PS‐b‐PI‐b‐PS) block copolymer is known for its self‐assembly characteristics and dual structure that combines rubber and thermoplastic materials. Conventionally, blends of block copolymers are fabricated using the melt blending method, a process that requires high temperatures. This study introduces an energy‐efficient solution blending method to enhance the compatibility between PS‐b‐PI‐b‐PS and natural rubber (NR) latex. NR latex was blended with PS‐b‐PI‐b‐PS in toluene at temperatures of 80, 100, 120, and 150°C and cast to form films. The solution‐blended film prepared at a moderate temperature of 120°C exhibited a maximum tensile strength of 9.48 MPa and was thermally degraded at higher temperature (382°C) than those produced by melt blending. The solution blending method also reduced the surface roughness and the particle size to between 7 and 500 nm and improved the interfacial adhesion in SB‐120°C blend compared to MB‐180°C blend. Molecular dynamics simulations indicated that the improved mechanical performance of the blend was primarily due to enhanced intramolecular bonding, with a maximized bond energy of 20,133 kcal/mol. This work demonstrates an energy‐efficient method with lower processing temperature for preparing polymer blends with improved compatibility suitable for various nanotechnology and engineering applications.Highlights Solution blending method improves the compatibility. Tensile strength and interfacial adhesion of the polymer blend improved. Solution blending reduces the particle size and surface roughness. Simulation shows an increase in intramolecular bond energy.

A novel experimental approach to exploring process parameters for fabricating support-free horizontal overhangs in LPBF of Inconel 718

ABSTRACT The design freedom of Laser Powder Bed Fusion (LPBF) components has been confined by the minimum allowable overhang angle of 45°. It remains unclear how to achieve multiple layers of overhang at zero-degree overhang angle, which is the fundamental basis of overhang. Here, we have confirmed the possibility of manufacturing three layers of support-free 0° overhang, but also demonstrated the robustness of the present approach via the successful manufacture of an overhang with 18 mm span. The stable dross thickness reveals that the laser drilling effect did not penetrate beyond the three-layer overhang. Furthermore, this research also demonstrates that the failure to manufacture long bridge overhangs was caused by severe consolidation rather than the conventional understanding of residual stress of the first few layers. The high correlation between porosity and surface roughness, and the etched melt pool reveal the underlying mechanism for low surface roughness for the horizontal overhang. Highlights An experimental approach is proposed to efficiently explore the parameter space. The present approach enables the manufacture of three layers of support-free overhang. The mechanisms for the successful and failed prints are elucidated. The relationship of Ra and porosity is proposed to further refine the parameters.

Influence of crystal orientation and incident plane on n-type 4H-SiC wafer slicing by using picosecond laser

Laser slicing has been considered as the most efficient technique for slicing SiC wafers with the advantages of small kerf width (loss) and crack, low roughness on cleaved surface, high quality and efficiency, etc. Here, laser slicing of n-type 4H-SiC was demonstrated by using a homemade 1064 nm picosecond laser combined with mechanical stretch stripping. The influence of laser processing along [11 2¯ 0] and [1 1¯ 00] crystal orientations on Si-face and C-face of n-type 4H-SiC, specifically on the internal laser ablation lines and cracks, the peeling tensile strength, and the surface roughness of the peeled surfaces was investigated. The semi-insulating 4H-SiC wafer laser slicing was conducted for comparison. Under the same laser conditions, laser slicing of semi-insulating 4H-SiC was easier than that of n-type. The laser modification quality along [1 1¯ 00] orientation was better than that along [11 2¯ 0] orientation for both the semi-insulating and n-type 4H-SiC and the reasons were explained. The results indicated that the optimal laser slicing scheme detailed laser scanning along [1 1¯ 00] orientation and incidence from the C-face. Finally, a 6-inch, 420.36 µm-thick n-type 4H-SiC wafer was successfully sliced.

Effect of Photolithographic Biomimetic Surface Microstructure on Wettability and Droplet Evaporation Process

In nature, engineering technology and daily life, wetting phenomena are widespread and have essential roles and significance. Bionics is becoming increasingly important nowadays and exploring the mechanism that influences biomimetic surface microstructure on droplet wetting process and heat and mass transfer characteristics is becoming more meaningful. In this paper, based on photolithography technology, SU-8 photoresist was used as raw material to prepare biomimetic surfaces with microstructures in various arrangements. The research results show that the wettability of biomimetic functional surfaces can be regulated by regulating the shape and arrangement of photoresist micro-pillars. At the same time, the effects of surface microstructure configuration and roughness on the heat and mass transfer processes within the droplets were also comprehensively studied. The results show that a biomimetic surface with cylindrical micro-pillars can effectively inhibit the evaporative cooling effect of the liquid–vapour interface. This effect becomes more evident with the increase in roughness, and the interface temperature difference can be reduced by up to 18%. Similarly, the biomimetic surface with cylindrical micro-pillars can also effectively promote the evaporation rate of sessile droplets, which can be increased by about 13%. In addition, the research also shows that regardless of the structure, substrate temperature changes will significantly impact the wetting phenomenon of the biomimetic surface. This study aims to guide the optimal design of biomimetic surfaces prepared based on photoresistance.

Synthesis and potent antibacterial activity of nano-CuFe2O4/MoS2@Ag composite under visible light

With antibiotic resistance on the rise due to misuse, the urgent need for new antibacterial materials has become paramount in global health. Herein, a CuFe2O4/MoS2 (CFM) composite with a large specific surface area was synthesized through a simple hydrothermal method and physical adsorption, and the subsequent loading of silver nanoparticles (Ag NPs) onto its surface yielded the nanocomposite CuFe2O4/MoS2@Ag (CFMA) with a rough defect-rich surface. The nanocomposite demonstrates remarkable antibacterial activity against Escherichia coli, Staphylococcus aureus, and drug-resistant Salmonella (T-Salmonella) by releasing metal ions that alter the electrical potential of bacterial cell membranes, compromise the integrity of cell membranes, and produce reactive oxygen species that lead to oxidative stress. It thus achieves an antibacterial rate of 96 % against the three tested bacterial strains within just 20 min at a concentration of 200 μg/mL. The composite exhibits a broad-spectrum antibacterial effect against Gram-negative and Gram-positive bacteria, as well as drug-resistant bacteria. Moreover, CFM acts as a carrier that effectively prevents the aggregation of Ag NPs, and the magnetism of CuFe2O4 facilitates the recovery of the antibacterial agent. This work provides new ideas and methods for the development of highly efficient, cost-effective, and biocompatible antibacterial materials.

The New Interpretation of the Photothermal Spectra of CdTe Samples After Different Surface Treatments

This article presents new research on the surface condition of bulk crystal samples after the following stages of surface treatment: grinding, polishing, and etching. Furthermore, it shows how the surface condition affects the photothermal signal’s spectral amplitude and phase characteristics (PZE). A new theoretical interpretation of the photothermal spectra of CdTe samples after different surface treatments is proposed. We demonstrate that the piezoelectric method is susceptible to the surface condition, and it allows for the estimation of the thickness of surface-damaged layers of samples, and for the analysis of their thermal parameters. The roughness of surfaces obtained from the AFM pictures is estimated and compared to the photothermal results.

Fabrication and machining of aluminum-reinforced graphite metal matrix composites

Shaping of aluminum alloys by chip removal has increased significantly in the industry. Accordingly, issues aiming to reduce friction between the tool and the workpiece and to increase tool life have gained importance. As a result, despite the common use of coolant, minimal lubrication, and cryogenic cooling, it is expected that studies for dry processing will increase day by day due to environmental damage and high costs of the coolant. In this study, the effects of reinforcing solid lubricants in aluminum alloys onto the tool wear and surface integrity during the cylindrical turning of composites were investigated. As a result of the study, it was measured that the reinforcement material graphite reduces the temperatures occurring in the cutting zone in the turning process by an average of 22.5%. Accordingly, improvements in surface roughness values were achieved, cutting tool wear was reduced and tool life was increased by approximately 27%. Within the scope of this study, it can be stated that sustainable production is achieved without using cutting fluids that are costly, harmful to the environment and human health.

MOF incorporated Polyethersulfone/Polylactic Acid ultrafiltration membranes for the catalytic removal of dyes via persulfate activation

This study synthesized novel nanocellulose/zeolitic Imidazolate Framework nanocomposite blended Polyethersulfone/Polylactic Acid (PES/PLA-CNF@ZIF-8) membranes through a modified phase inversion process. This is the first time that a nanocellulose-MOF composite catalytic nanomaterial has been synthesized and used as an additive in polymeric membranes. The morphology and chemical structure of the membranes and nanoparticles were characterised by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Fourier transform infrared (FTIR) respectively. Membrane wettability and crystalline structure were characterised by contact angle, and X-ray diffraction (XRD) analysis respectively. CNF@ZIF-8 modified membranes showed improved contact angle which decreased from 76° in the pristine membranes to 40° in 2 wt% membranes, bulk porosity increased from 74.3.3 % to 81.06 % while the pure water flux increased from 208.30 Lm-2h−1 to 348.73 Lm-2h−1. Further, the modified membranes showed an increase in surface roughness reaching 84.14 nm in 2 wt% membranes. The synthesized membranes have been used as catalysts in the activation of persulfate to degrade Rhodamine B dye. The modified membranes displayed a high catalytic effect (>90 %) in activating persulfate to degrade RhB dye when compared to pristine membranes which showed a degradation efficiency of < 35 %. The study found that the optimum parameters for pH, membrane (catalyst) dosage, oxidant and initial dye concentration were 5, 0.3 g, 0.4 mM and 10 ppm respectively. Quenching experiments showed that •SO4- and •OH radicals were responsible for the dye degradation, with •SO4- radicals playing a major role in the oxidative degradation of the RhB dye. The synthesized membranes showed good stability when tested within five cycles, with the membranes showing degradation efficiency ranging from 92.1 % in the 1st cycle to 91.9 % in the 3rd cycle, before decreasing to 75.3 % in the 5th cycle. This study has therefore shown that the synthesized PES/PLA-CNF@ZIF-8 membranes have potential for use as catalysts in the degradation of cationic dyes in wastewater treatment through persulfate activation.