Surface Roughness Characteristics Research Articles

Parametric optimization and sensitivity analysis of the integrated Taguchi-CRITIC-EDAS method to enhance the surface quality and tensile test behavior of 3D printed PLA and ABS parts.

3D printing is a popular and cost-effective method for producing lightweight engineering parts with enhanced characteristics and detailed prototypes. Nevertheless, the quality of the print can be diminished by the selection of improper parameter settings. This investigation explored the impact of printing factors on the tensile behavior of polylactic acid (PLA) and Acrylonitrile Butadiene Styrene (ABS) specimens. Experimental investigations were conducted to investigate the effects of infill pattern (grid, 2D, and 3D honeycomb), layer thickness (0.10, 0.15, and 0.20mm), infill percentage (30%, 50%, and 70%), and printing material on surface roughness and tensile characteristics where an irregular dependency was identified. In this scenario, the Evaluation based on Distance from Average Solution (EDAS) Method was integrated with Taguchi and Criteria Importance through Inter-criteria Correlation (CRITIC) to prevent inconsistent judgments with a minimal number of experiments. PLA printed parts with 2D honeycomb design, 0.10mm layer thickness, and 50% infill provided the optimum results within the declared boundary conditions. The robustness and sensitivity of the employed MCDM method were assessed through a comprehensive analysis. The weights determined through other techniques, including the equal method, principal component analysis (PCA), and Entropy, were subsequently compared to CRITIC. The results indicated a stronger correlation between PCA and CRITIC. Furthermore, the Pearson correlation matrix results indicated that EDAS was significantly correlated with the MOORA method in comparison to the other methods (ARAS, WASPAS, GRA, COPRAS, and CODAS).

In-Situ Nanoindentation Surface Topography of Lead-Free Piezoelectric Thin Films

Surface roughness significantly affects the performance of microelectromechanical systems (MEMS) and piezoelectric films. This study investigates the impact of surface roughness on the mechanical properties of thin piezoelectric films using nanoindentation and scanning probe microscopy (SPM). Four piezoelectric films with different thicknesses (220, 350, and 450 nm) and substrate configurations (LNO/SiO2/Si or LNO/Si) were analyzed. A discriminant analysis revealed that the fractal dimension is more effective than the arithmetic mean height (Sa) for distinguishing surfaces, with only 2% misclassification versus 25% for Sa. A multiscale analysis identified the Smr2 parameter with low-pass filtering at 140 nm as highly effective for surface discrimination, achieving only 0.1% misclassification. The analysis of the roughness parameter Sa at various scales showed that band-pass filtering at 500 nm yielded a 0.7% misclassification rate, indicating its relevance for fractal roughness characterization. Most relevant roughness parameters for mechanical property correlation were found: Smr2 with low-pass filtering at 500 nm correlated best with hardness (R2 = 0.82), and Vvc with low-pass filtering at 2 nm correlated best with reduced elastic modulus (R2 = 0.84). These results demonstrate that surface roughness features like valley volume and voids significantly impact the apparent mechanical properties of piezoelectric films.

Transition Metal Dichalcogenide‐Based Composites in Powder Bed Additive Manufacturing for Electrochemical Applications—A Review

AbstractRobust electrochemical sustainability of tailored high‐performance nanocomposites is integral to advanced electrochemical energy conversion and storage (EECS) systems. Functions, such as nanoscale ionic‐diffusion distance, electrocatalytic reactions, electrical conductivity, and fluid distribution, of transition metal dichalcogenide (TMD)‐based nanostructures have been extensively designed and studied. However, challenges in materials selection, operational scalability, and design flexibility of TMD‐incorporated metal‐matrix composites (MMCs) consisting of non‐noble metallic nanostructures and their originating TMD materials have scarcely been studied. Highlighting the effectiveness of emerging additive manufacturing techniques in sustainable energy supply and storage, laser powder bed fusion (L‐PBF) can offer a directly added dual‐functionality to fabricated complex multimaterial and TMD‐incorporated MMC electrocatalytic electrodes. In this review, the characteristics of composite powder feedstock and optimizing process parameters are critically emphasized from another perspective to maintain a balance between mechanical robustness and enhanced electrochemical response. It is demonstrated how factors such as surface roughness, particle shape, and rheological characteristics of TMDs can influence the flowability of composite powder feedstock and the electrochemical performance of L‐PBF‐processed electrodes. The review further aims to contribute compiled information for use in the rapidly growing global market for advanced energy storage systems, underscoring the transformative potential of L‐PBF and TMD‐incorporated MMCs in modernizing the EECS components.

Comparative Analysis of Surface Roughness and Design Features of Titanium Dental Implants on Primary Stability and Osseointegration

ABSTRACT Objective: This study aimed to evaluate the impact of the surface roughness and design features of titanium dental implants on primary stability and osseointegration. Methods: Sixty titanium dental implants were categorized into three groups based on their surface roughness: smooth (Subgroup A1), moderately rough (Subgroup A2), and highly rough (Subgroup A3). Each roughness category was further divided into three design subgroups: cylindrical (B1), tapered (B2), and hybrid (B3). Primary stability was assessed using insertion torque and resonance frequency analysis (RFA). Osseointegration was evaluated through histological and histomorphometric analyses, measuring bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) at 4, 8, and 12 weeks post-implantation in rabbit models. Results: Highly rough-surface implants (Subgroup A3) demonstrated significantly higher insertion torque and ISQ values than smooth (Subgroup A1) and moderately rough (Subgroup A2) implants (P < 0.001). Among the design features, tapered implants (Subgroup B2) exhibited the highest insertion torque and ISQ values (P < 0.001). Histological and histomorphometric analyses revealed that highly rough-surface implants (Subgroup A3) and tapered implants (Subgroup B2) had the highest BIC and BAFO percentages at all time points (P < 0.001). Conclusion: These findings indicate that both surface roughness and implant design significantly influence primary stability and osseointegration.

Analysis and optimization for plunging forces of a drive-shaft system considering rough surface characteristics under hybrid uncertainty

Analysis and optimization for plunging forces of a drive-shaft system considering rough surface characteristics under hybrid uncertainty

Exploring the influence of surface roughness on the interface phenomenon between an air bubble and a glass bead: An experimental and theoretical investigation

The effect of surface roughness on the detachment between the bubbles and the glass beads (soda-lime) was comprehensively investigated. Glass beads with dimensions of −1.20 + 1.12 mm were acid etched to achieve varying degrees of surface roughness, followed by silanation reactions conducted for different immersion times. The characterization of surface roughness was conducted using a ContourGT-K 3D optical microscope. Measurements of receding contact angle, induction time and detachment force were conducted to assess the influence of surface roughness on bubble and glass bead attachment/detachment. It is observed that the etching surface of glass beads with uniform protrusions and depressions, the hydrophobic glass beads exhibited shorter induction time, larger contact angle and higher critical detachment force. However, the stability of aggregates of bubbles and hydrophilic glass beads was reduced, making them prone to detachment. Moreover, larger protrusions and depressions on hydrophobic glass bead surfaces with increasing etching time, resulted in an increase in induction time, a decrease in receding contact angle and critical detachment force. The stability of bubbles and hydrophilic glass bead aggregates remained unchanged.

Investigation of the Microhardness, Morphology, and Wear Resistance of A7075 Subjected to Machine Hammer Peening

In industrial production, 7075 aluminum alloy (A7075) is prized for its strength and light weight. However, heat treatment can reduce its hardness and wear resistance. Therefore, proper surface treatments are often necessary to optimize its mechanical properties. In this work, a hammering tool attached to a robotic arm was employed to impact the surface of A7075 using different impact energies, and the surface hardness, morphology, roughness, and frictional characteristics of samples subjected to machine hammer peening (MHP) treatment were analyzed to explore the strengthening mechanism of MHP. The results indicate that the hardness increased to a maximum value of 235 HV with rising impact energy, whereas the depth of influence (2 mm) was almost unaffected by the impact energy. Microstructural analysis revealed significant grain refinement, especially at 2.7 J. The surface roughness increased significantly to about 7.2 μm, then dropped to around 3.7 μm when the impact energy increased to 2.7 J. Finally, the roughness decreased to ~6.8 μm. In addition, the samples that were strengthened by MHP demonstrated low friction coefficients (about 0.27) and wear volume (minimum value of 7.67/10−4 mm3), implying that MHP can effectively improve the wear resistance of A7075. Observation by SEM revealed that the corresponding wear mechanism is mainly attributable to mild oxidative wear and three-body wear.

On the Effect of Randomly Oriented Grain Growth on the Structure of Aluminum Thin Films Deposited via Magnetron Sputtering

The microstructure of aluminum thin films, including the grain morphology and surface roughness, are key parameters for improving the thermal or electrical properties and optical reflectance of films. The first step in optimizing these parameters is a thorough understanding of the grain growth mechanisms and film structure. To investigate these issues, thin aluminum films with thicknesses ranging from 25 to 280 nm were coated on SiOx/Si substrates at ambient temperature under high-vacuum conditions and a low argon pressure of 3 × 10−3 mbar (0.3 Pa) using the radio frequency magnetron sputtering method. Quantitative analyses of the surface roughness and nanograin characteristics were conducted using atomic force microscopy (AFM), transmission electron microscopy (TEM), and X-ray diffraction. Changes in specular reflectance were measured using ultraviolet–visible and near-infrared spectroscopy. The low roughness values obtained from the AFM images resulted in high film reflectivity, even for thicker films. TEM and AFM results indicate monomodal, randomly oriented grain growth without a distinct columnar or spherical morphology. Using TEM cross-sectional images and the dependence of the grain size on the film thickness, we propose a grain growth mechanism based on the diffusion mobility of aluminum atoms through grain boundaries.

Characterization of micro-wire electrical discharge machining surface texture by empirical mode decomposition

Surface roughness is a critical factor for the operational efficacy and lifespan of the manufactured components, often serving as a key metric for evaluating manufacturing processes and determining acceptance of a component. Traditional surface roughness measurements are highly sensitive to the fixed standard cut-off length, influencing the scale at which surface texture features are analyzed. Thus, developing techniques with more reliable filtering of surface features is essential for accurate surface metrology. This research proposes a novel method that combines Empirical Mode Decomposition (EMD) and Fast Fourier Transform (FFT) for surface roughness characterization. We applied our method to Nitinol shape memory alloy (equal atomic proportions of nickel and titanium) surfaces processed using micro-Wire Electrical Discharge Machining (μ-WEDM). Our results demonstrate that the EMD-FFT method significantly outperforms traditional filtering, especially for surfaces without distinct patterns like μ-WEDM. This improvement is particularly valuable for materials like Nitinol, which is widely used in critical applications where precise surface roughness control is essential. By accurately assessing the effects of μ-WEDM parameters on surface roughness, the proposed method reveals that for a constant pulse on time and a constant discharge current, the variation of pulse off time is more important than servo voltage. Thus, this method can contribute to optimizing manufacturing processes and producing higher-quality components with improved performance and durability.

Influence of Detonation Spraying Parameters on the Microstructure and Mechanical Properties of Hydroxyapatite Coatings.

The process of osteointegration depends significantly on the surface roughness, structure, chemical composition, and mechanical characteristics of the coating. In this regard, an important direction in the development of medical materials is the development of new techniques of surface modification and the creation of bioactive ceramic coatings. Calcium-phosphate materials based on hydroxyapatite have been proposed as bioactive ceramic coatings on titanium implants for the effective acceleration of bone tissue healing. To obtain bioactive ceramic coatings, pulse power sources are best suited, namely detonation spraying, in which the energy of the explosion of gas mixtures is used as a source of pulse action. The pulse mode of operation in the detonation spraying method is preferable for the formation of bioactive ceramic coatings. It provides a high velocity of hydroxyapatite particles, which promotes their effective fixation on the titanium substrate, while minimizing the heating of the material. This approach preserves the substrate structure and improves the coating adhesion. Four different types of coatings with varying O2/C2H2 molar ratios, ranging from 2.6 to 3.7, were obtained using detonation spraying. Powders and obtained coatings of hydroxyapatite were studied by Raman spectroscopy and XRD structural analysis. The results of XRD phase analysis showed the partial conversion of the hydroxyapatite phase to the α-tricalcium phosphate (α-TCP) phase during the detonation spraying process. The results obtained by Raman spectroscopy indicate that hydroxyapatite is the main phase in coatings. All hydroxyapatite-based coatings exhibited hydrophobic properties, which was confirmed by contact-angle values above 90° in wettability tests, characteristic of hydrophobic surfaces. The adhesive strength of the coatings was measured by the scratch test method. Tribological tests were conducted using the ball-on-disk method under both dry conditions and in Ringer's solution. This approach enabled the evaluation of wear resistance and friction coefficient of the coatings in different environments, simulating both lubrication-free conditions and those resembling physiological environments.

Surface condition driven fatigue performance of laser powder bed fusion H13 steel

Surface variation is an inherent imperfection in the laser powder bed fusion (LPBF) processed samples, comprising of primary roughness (PRR) from the melt pool solidification and secondary roughness (SER) from adhered powder particles. Components under cyclic loading are sensitive to surface defects, making surface finishing crucial for fatigue-bearing parts. However, this undermines LPBF’s advantage of creating high-performance and geometrically complex components. This study examines the effect of surface roughness on fatigue crack initiation in LPBF H13 steel, a high-strength alloy with a tensile strength of 1800 MPa. The focus is on scenarios where contour scanning strategies are not employed. Vertically deposited samples were subjected to three surface conditions: as-built (AB) with PRR + SER, half-polished (HP) with only PRR, and well-machined (M) with no PRR or SER. Optical and digital surface roughness characterization and stress-controlled fatigue testing were performed. Results revealed that while AB-samples showed significantly rough surface compared to HP-samples, their fatigue performance did not reduce. In contrast, M-samples had a slight improvement in roughness but exhibited a fatigue life increase by a factor greater than 17. This was attributed to the PRR, specifically the solidification valleys between the neighboring melt pools. Factographic analysis showed that the PRR-driven fatigue crack initiation is a critical determinant of fatigue performance.

Experimental Analysis of Terahertz Wave Scattering Characteristics of Simulated Lunar Regolith Surface

This study investigates terahertz (THz) wave scattering from a simulated lunar regolith surface, with a focus on the Brewster feature, backscattering, and bistatic scattering within the 325 to 500 GHz range. We employed a generalized power-law spectrum to characterize surface roughness and fabricated Gaussian correlated surfaces from Durable Resin V2 using 3D printing technology. The complex dielectric permittivity of these materials was determined through THz time-domain spectroscopy (THz-TDS). Our experimental setup comprised a vector network analyzer (VNA) equipped with dual waveguide frequency extenders for the WR-2.2 band, transmitter and receiver modules, polarizing components, and a scattering chamber. We systematically analyzed the effects of root-mean-square (RMS) height, correlation length, dielectric constant, frequency, polarization, and observation angle on THz scattering. The findings highlight the significant impact of surface roughness on the Brewster angle shift, backscattering, and bistatic scattering. These insights are crucial for refining theoretical models and developing algorithms to retrieve physical parameters for lunar and other celestial explorations.

Investigation of surface structuring and oxidation performance of Inconel 718 superalloy by laser remelting with different patterns

The current paper deals with the effect of CO2 laser remelting on the surface structuring and oxidation performance of Inconel 718 superalloy, pointing out different laser-induced surface patterns that make a difference in their oxidation properties vital for high-temperature applications. Surface roughness, microstructure, and oxidation behavior characterization were performed using 3D optical profilometry, SEM, and XRD techniques. The oxidation tests conducted at 1000 °C for 24 h have revealed that remelted surfaces offered better oxidation resistance compared to untreated samples. Notably, the patterned sample showed the lowest weight gain under oxidation, and a parabolic regime in oxidation occurred after 100 min; while in an untreated reference sample, this appears only after 200 min. This improvement in performance results from the formation of a chromium-rich oxide layer on the melt pools, which acts as an effective barrier against further oxidation. The findings show that laser remelting, especially with grid-like surface patterns, results in an improvement in both durability and high-temperature performance of Inconel 718; therefore, it is apparently a very promising technique for lifespan extension of industrially relevant materials.

Microstructure analysis of SS316L using Selective Laser Melting

Abstract Additive manufacturing has emerged as a prominent and expanding domain in materials engineering, driven by a rising need for customized, highly accurate, and readily available production. Applying the selective laser melting (SLM) technique further is delayed by the layer-by-layer melting and solidification of the metal powder. The impeller constructions were extracted from a substrate, with the bending curvature as an indicator of the stress level. This research aims to analyze the quality of impeller components, surface roughness, and microstructural features of components made for the SS316L. The microstructure examinations show the part is free from the surface and internal defects are verified.

Using bearing ratio curves to quantify the surface roughness parameters of fly ash-teff straw ash-based geopolymer mortars

Considering the prominent attributes of surface roughness parameters, the closer their solutions are to real surfaces, the more appropriate they are for civil engineering applications. One of the steps that can be considered for such applications is to incorporate the bearing ratio curve (BRC) parameters in the study of civil engineering materials. In this research, the bearing ratio curves have been used for the first time to quantify the surface roughness attributes of fly ash-teff straw ash-based geopolymer mortars. For various cases, the roughness parameters in the V-group are compared with the roughness parameters in the Rk group, which contributes to the attractiveness of this research. The fly ash-teff straw ash-based geopolymer mortar specimens in this study are dominated by smooth surfaces, as evidenced by the Rvk and Rpk values of less than 0.21 μm for all specimens. The study highlights that if such surfaces are to be used in mortar-to-mortar bonding, imposed surface roughness could be required to enhance the bond strength of the layers. In addition, the results indicate that critical roughness parameters can be identified from the bearing ratio curves when a surface is undergoing roughness transformations. These findings provide a step towards the understanding of BRC parameters for fly ash-teff straw ash-based geopolymer mortar surfaces. Overall, the approach demonstrated in this study could also accelerate and promote the surface roughness characterisation for geopolymer mortars and could be extended to unlock peculiar surface roughness properties for other civil engineering materials.

Low-Reynolds-number droplet motion in shear flow micro-confined by a rough substrate

A three-dimensional spectral boundary element method has been employed to compute for the dynamics of the droplet motion driven by shear flow near a single solid substrate with a rough surface. The droplet size is comparable with the surface features of the substrate. This is a problem that has barely been explored but with applications in biomedical research and heat management. This work numerically investigated the influences of surface roughness features, such as the roughness amplitude and wavelength, on the droplet deformation and velocities. We observe that a greater amplitude or wavelength leads to larger variations in droplet velocity perpendicular to the substrate. The droplet velocity along the substrate increases when the amplitude is reduced or when the wavelength increases. The effects of capillary number and viscosity ratios have also been studied. The droplet deformation and its velocity increases as we increase the capillary number, while the viscosity ratio shows a non-monotonic influence on the droplet behavior. The predicted droplet behaviors, including deformation, velocities, and trajectories, can provide physical insight, help to understand the droplet behavior in microfluidic devices without a perfectly smooth surface, and contribute in the design and operation of those devices.

Multicycle Characterization of Surface Roughness in Stereolithography-based Additive Manufacturing Using a Methacrylate-based Thermoresponsive Copolymer

Multicycle Characterization of Surface Roughness in Stereolithography-based Additive Manufacturing Using a Methacrylate-based Thermoresponsive Copolymer

Optimizing surface properties in pure titanium for dental implants: a crystallographic analysis of sandblasting and acid-etching techniques

Surface roughness is a critical factor affecting the performance of dental implants. One approach to influence this is through sandblasted, large grit, acid-etched (SLA) modification on pure titanium implant surfaces. In this study, SLA was performed on grade IV pure titanium. Sandblasting was conducted at distances of 2, 4, and 6 cm. Subsequently, the samples were etched with a mixed acid solution of HCl, H2SO4, and H2O for 0, 30, and 60 min. Surface roughness and X-ray diffraction (XRD) characterizations were conducted on the samples. The results revealed that surface roughness increased but was not too significant as the sandblasting distance decreased. Longer etching durations for sandblasted with acid-etched samples led to reduced surface roughness (Sa and Sz). It was found that a 60 min-etched sample resulted in optimal Sa, Sz, and Ssk values, i.e., 1.19 μm, 13.76 μm, and −0.60, respectively. The XRD texture was significantly influenced by sandblasting, with compressive residual stress increasing as the sandblasting distance decreased. Normal stress causes hill formations at shorter sandblasting distances. For etched samples, the residual stress decreased with longer etching durations. Normal stress-decreasing trend aligns with the initial reduction in hill and valley within the samples and subsequent hill enhancement at extended etching duration.

Study of the Characteristics of Ba0.6Sr0.4Ti1-xMnxO3-Film Resistance Random Access Memory Devices.

In this study, Ba0.6Sr0.4Ti1-xMnxO3 ceramics were fabricated by a novel ball milling technique followed by spin-coating to produce thin-film resistive memories. Measurements were made using field emission scanning electron microscopes, atomic force microscopes, X-ray diffractometers, and precision power meters to observe, analyze, and calculate surface microstructures, roughness, crystalline phases, half-height widths, and memory characteristics. Firstly, the effect of different sintering methods with different substitution ratios of Mn4+ for Ti4+ was studied. The surface microstructural changes of the films prepared by the one-time sintering method were compared with those of the solid-state reaction method, and the effects of substituting a small amount of Ti4+ with Mn4+ on the physical properties were analyzed. Finally, the optimal parameters obtained in the first part of the experiment were used for the fabrication of the thin-film resistive memory devices. The voltage and current characteristics, continuous operation times, conduction mechanisms, activation energies, and hopping distances of two types of thin-film resistive memory devices, BST and BSTM, were measured and studied under different compliance currents.

Comparative investigation of heat extraction performance in 3D self-affine rough single fractures using CO2,N2O and H2O as heat transfer fluid

The type and thermophysical properties of heat transfer fluids significantly impact the heat extraction rate of Enhanced Geothermal Systems (EGS). Studies based on field-scale stochastic discrete fracture network geometric models have certain limitations and uncertainties. To compare the heat extraction performance of heat transfer fluids H2O, CO2, and N2O in a core-scale (φ50 × 100 mm) rough single fracture in hot dry rock, we first constructed the fracture geometry with rock surface roughness characteristics using a fractal self-affine function, with a joint roughness coefficient (JRC) of 12.38. Then, at temperatures ranging from 37 to 300°C and a pressure of 30 MPa, we established a thermo-hydraulic (TH) coupling model based on the thermophysical parameter equations of the three heat transfer fluids. Finally, we conducted a comparative study of the changes in the outlet mean temperature and heat extraction rate after flowing through the fracture, as well as the temperature distribution on the fracture surface, under conditions of constant inlet flow velocity with varying inlet temperature and constant inlet temperature with varying inlet flow velocity. The results indicate that (1) with the increase in inlet flow velocity and temperature, the outlet mean temperature and heat extraction rate of CO2 and N2O at the fracture outlet are essentially the same and lower than those of H2O. (2) When the inlet flow velocity increases from 0.005 m/s to 0.025 m/s, the thermal convection effect from the rock matrix to the fluid in the fracture predominates, and flow velocity is the main factor affecting the heat transfer process between the fluid and the rock matrix. When the inlet temperature increases from 37°C to 57°C, the thermal conduction effect from the rock matrix to the fluid in the fracture predominates, and temperature is the main factor affecting the heat transfer process between the fluid and the rock matrix.(3)When maintaining constant inlet temperature, increasing inlet flow velocity from 0.005 m/s to 0.025 m/s results in CO2 experiencing a maximum heat extraction rate increase of 118.85 W. In contrast, N2O experiences 117.05 W, and H2O experiences 266.4 W.(4) When the inlet flow rate is constant, the maximum increase in heat extraction rate for CO2 is 15.34 W as the inlet temperature increases from 37 °C to 57 °C; for N2O, it is 13.9 W; and for H2O, it is 45.45 W.