Effect Of Surface Texture Research Articles

Effect of Surface Cracks and Texture on Residual Stresses in Tungsten after Exposure to Plasma

Effect of Surface Cracks and Texture on Residual Stresses in Tungsten after Exposure to Plasma

Droplet Memory on Liquid-Infused Surfaces.

The knowledge of droplet friction on liquid-infused surfaces (LIS) is of paramount importance for applications involving liquid manipulation. While the possible dissipation mechanisms are well-understood, the effect of surface texture has thus far been mainly investigated on LIS with highly regular solid topographies. In this work, we aim to address this experimental gap by studying the friction experienced by water droplets on LIS based on both random and regular polysilsesquioxane nanostructures. We show that the available models apply to the tested surfaces, but we observe a previously unreported droplet memory effect: as consecutive droplets travel along the same path, their velocity increases up to a plateau value before returning to the original state after a sufficiently long time. We study the features of this phenomenon by evaluating the motion of droplets when they cross the path of a previous sequence of droplets, discovering that moving droplets create a low-friction trace in their wake, whose size matches their base diameter. Finally, we attribute this to the temporary smoothing out of an initially conformal lubricant layer by means of a Landau-Levich-Derjaguin liquid film deposition behind the moving droplet. The proposed mechanism might apply to any LIS with a conformal lubricant layer.

Effect of surface texture positioning in grease lubricated contacts

It is generally established that use of well-designed artificially enhanced surfaces in certain lubricated conjunctions can potentially improve the tribological performance under specific operating conditions. However, there is a considerable lack of understanding of the effect of texture features, which are not exposed to conditions in the contact footprint, to the overall tribological performance. Three discs have been manufactured, one without texture features and two with texture features but in different locations with respect to contact footprint. The discs were tested in a ball on disc tribometer under representative contact conditions from practical application cases as such contacts can experience a multitude of regimes of lubrication during the operation. The contacts were lubricated by grease. Texture features placed directly beneath the contact were shown to provide a negative effect by increasing the measured coefficient of friction relative to the untextured disc. Textures placed outside, but at very close proximity of the contact footprint track on the disc, were shown to reduce the measured friction coefficient and wear simultaneously.

Theoretical and Experimental Study on Normal Contact Stiffness of Plane Joint Surfaces With Surface Texturing

Effects of surface texturing on normal contact stiffness have been investigated by experiments in previous research studies; however, there are relatively few theoretical models in this regard. This article aims to investigate the influence of surface texturing on the normal contact stiffness in theory and experiment. In the present research, a rough surface with surface texturing is divided into two parts, the textured zone and the remaining zone, and their theoretical models of normal contact stiffness are established respectively, considering surface morphology and material properties. For the textured zone, microtextures are modeled theoretically based on the three-dimensional topographic data obtained via a laser profilometer. For the remaining zone, the surface topography is characterized based on fractal theory, and a calculation model is established considering the elastoplastic deformation of surface asperities. In the experiment, the normal contact stiffness of specimens is obtained through the self-developed experimental platform. The proposed theoretical model is appropriate through the comparison of test results and theoretical predictions. The research results show that the effect of surface texture on the contact stiffness is related to the surface roughness, Sa. For the joint surfaces with Sa > 2.69 μm, the normal contact stiffness can be effectively increased through proper surface texturing.

The effect of laser surface textures on the adhesion strength and corrosion protection of organic coatings - Experimental assessment using the pull-off test and the shaft load blister test

Adhesion is necessary for an effective corrosion protection of metallic surfaces through organic coatings. Even the best anticorrosive coatings fail if it is not well adhered to the substrate. Laser surface texturing (LST) process has been widely used for enhancing adhesion between coatings and steel surfaces in various applications. In addition, recent researches have proven that LST is an effective option for pretreatment of steel surfaces prior to organic coating deposition. This work reports an investigation on the adhesion strength of organic coatings deposited onto AISI-A36 carbon steel laser-textured surfaces. Nanosecond LST via the direct laser writing (DLW) method was used to fabricate V-shaped grooves on the steel surfaces. The distance between consecutive grooves was varied to obtain different surface topographies with controlled surface textured area (TA) ranging from 10 % to 60 %. Conventional bead-blasted surfaces were used as a reference. Surface morphology and topography were characterized through roughness and tortuosity. The frequently used pull-off test (ISO 4624) and a shaft load blister test (SLBT) were used to determine the adhesion of the epoxy coating. In addition, accelerated corrosion tests were carried out to assess the effects of the laser textured surface conditions on the corrosion propagation. After running the pull-off test, all the surfaces' conditions exceeded the minimum pull-off strength value of 5 MPa stated in ISO 12944-9. The results for the SLBT showed that the adhesive strength is highly influenced by the laser-textured area. The geometrical aspects of the groove structure promote phenomena such as mechanical interlock and mechanical hooking of the coating, which affect the adhesion failure mechanism of the organic coating during the test. For lower TA, the crack propagation occurs mainly at the coating/steel interface. However, increasing the TA shows that the crack propagation is stopped near the V-shaped grooves due to the complex shape and must deviate inside the coating for further propagation. Finally, adhesion strength results were correlated with coating delamination rates and an indirect relationship was found.

Investigating the Synergistic Effect of Electrochemical Texturing and MoSeC Coatings on the Frictional Behaviour of Lubricated Contacts

The materials used for the piston cylinders of automobile engines, or the ring and tappets of various mechanical components, are continuously experiencing lubricated sliding motions. These surfaces are prone to damage due to the various tribological aspects of friction and wear. Hence, enhancing their surface properties would contribute to increasing their life and saving energy and resources. For many decades surface texturing and surface coating technology have been studied to improve the surface tribological behaviours of the materials. In the present study, the steel surface was textured with electrochemical processing (ECP) and post-coating with transition metal dichalcogenides (TMD) using a molybdenum-selenium-carbon (MoSeC) film. A comparative study was conducted to investigate the synergistic effect of surface texturing and coating to improve frictional properties on the steel surface. The block-on-ring experiments were performed under lubricated conditions to understand the improvement of COF at different lubrication regimes. It has been seen that the MoSeC-coated circular patterns exhibited improvements in the frictional properties at all the lubricated conditions if compared with smooth surfaces.

The Effect of Initial Texture on the Plastic Deformation of Gradient Aluminum.

The effect of specific processing-induced surface textures in gradient aluminum has not yet been investigated. A dislocation-based multi-scale framework is employed to explore the influence of various initial shearing textures and the depth from the surface of the region featuring each texture on the macroscopic behavior of gradient aluminum. By assigning different textures to the same grain size gradient aluminum sample, the initial texture was found to significantly affect the plastic deformation and macroscopic behavior of gradient aluminum. Specifically, the {111} texture can enhance the strength-ductility synergy, and this effect is dependent on the depth from the surface where the texture is located. This texture can lead to a slow stress/strain gradient in the assigned texture region and a sharp stress/strain gradient in the grain size gradient region connecting this region with the coarse grain region. Particularly, the sharp stress/strain gradient can result in extra strengthening by adjusting the stress/strain localization. These findings provide valuable insights for the design and optimization of surface textures in gradient aluminum.

Effect of laser surface texturing and boriding on the tribocorrosion resistance of an ASTM F-1537 cobalt alloy

Different kinds of materials are broadly employed to manufacture bioimplants. Metals are commonly used for the fabrication of lower body components such as knee prostheses and hip replacements because of their good mechanical properties. Among the available metallic biomaterials, cobalt alloys are commonly used. However, the hostile environment of the human body promotes the corrosion of the metallic bioimplant, and the wear due to the sliding contact could also increase the corrosion. There is, therefore, a constant attempt to study the surface of metallic biomaterials to enhance their functionality. In the present work, two kinds of surface modification techniques were employed on ASTM F-1537 cobalt alloy samples: laser surface texturing and boriding. Tribocorrosion tests were carried out using a linear reciprocating tribometer coupled with a standard three-electrode electrochemical cell. Tafel polarization plots were used to calculate the material loss due to corrosion. Also, non-contact profilometry was employed to estimate the tribocorrosion volume loss. In addition, the worn tracks were analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The textured + borided samples increased 1.5 times the tribocorrosion resistance compared to the untreated samples. The differences in the tribocorrosion performance among the modified surfaces were discussed in this paper.

Effect of surface texture, viewing angle, and surface condition on the emissivity of wire arc directed energy deposition manufactured 7075 nano treated aluminum alloy

Effect of surface texture, viewing angle, and surface condition on the emissivity of wire arc directed energy deposition manufactured 7075 nano treated aluminum alloy

Effect of Surface Texture on Light Extraction Efficiency for LEDs

The light extraction efficiency of an LED is dependent on its surface texture. However, the surface of the p-GaN layer is not easy to be etch with inverted hexagonal pyramid structures (IHPS) with small top widths and large depths using existing methods. Therefore, it is important to discuss the expected effect of the conditions of thermal annealing and inductively coupled plasma (ICP) reactive ion etching (RIE) for the generation of nano-pin-holes in the photoresist and fabrication of the top surface structure of GaN-based LEDs, in order to enhance the light output power. In this study, the following four items will be discussed: (1) the effect of thermal annealing on the composition of the photoresist; (2) the effect of thermal annealing and ICP RIE on the generation of the nano-pin-holes in the photoresist; (3) the effect of ICP RIE on the IHPS; and (4) the effect of surface texture of the IHPS on the light output power. It has been found that a nano-pin-hole structure in the photoresist etching mask is needed for the fabrication of many IHPS on the LED surface. A maskless via-hole etching technique was used for texturing the photoresist to produce nano-pore structures with diameters of less than 50 nm. The relationship between the light extraction efficiency and the surface texture is discussed in detail. The simulation results show the best light extraction efficiency (LEE) ratio of 358% to be obtained when the distance between two neighboring IHPS patterns (DBNP) is 300 nm. This in turn allowed the formation of IHPS with small top widths and large depths on the LED surface. A LEE ratio of 305% was obtained with the fabrication of IHPS with a top width of 290 nm, a depth of 170 nm and a DBNP of 180 nm on the LED surface.

Effect of selective atomic clustering, surface texture and grain boundary constitution on the corrosion behaviour of electrodeposited Sn-xBi coatings

Sn-xBi (x = 4, 7, 10, 14, and 17 wt%) coatings were electrodeposited onto mild steel to elucidate their corrosion behaviour. The B14 (Sn-14 wt% Bi) and B7 (Sn-7 wt% Bi) coating exhibited the highest (Polarization resistance (Rp) = 12,810.2 Ω·cm2) and least corrosion resistance (Rp = 2843.2 Ω·cm2), respectively. B14 coating exhibited the lower energy near (301) plane orientation against B7 coating which showed higher energy (321) and (111) plane orientation along the exposed surface. The galvanic coupling effect alleviated in B14 coating due to Sn nanoclusters into Bi grains as revealed by the atom probe tomography analysis.

Effect of ultrasonic nanocrystal treatment combined with nitriding process on fretting wear behavior of textured 20CrMoH steel

Individual and synergy effects of laser surface texturing (LST) followed by plasma nitriding (PN) and surface ultrasonic nanocrystal technology (SUNT) on fretting wear behaviors of 20CrMoH steel were systematically investigated at various loads and lubrication conditions. Results indicated that the combined treated (LST + PN + SUNT) 20CrMoH steel got the lowest surface roughness Ra value of 0.46 μm, the highest surface microhardness of 940 HV0.2, and the maximum residual compressive stress (RCS) value of −750 MPa. Consequently, the best fretting wear resistance was obtained by the combined treated 20CrMoH steel. Wear loss of untreated specimen reduced by 131 % after the combined treatment. The predominant wear mechanisms of the untreated, PN treated and LST + PN treated 20CrMoH steel under dry friction were oxidation wear and delamination. Besides, Oxidation and adhesion occurred for the combined treated specimen in dry friction. Especially, texture, residual stress and microhardness are key factors enhancing the anti-wear resistance.

Asymmetric surface texturing for directional friction control under dry sliding condition

This study investigated the effects of asymmetric surface texturing on directional friction under dry condition. Asymmetric micro-grooves were radially textured on electroless nickel phosphorous (Ni–P) plated disk using a single-point diamond cutting process. Using a ball-on-disk tribometer, sliding tests in clockwise (CW) and counter-clockwise (CCW) directions against polyether-ether-ketones (PEEK) material were carried out at different texture densities. Results show that asymmetric surface texturing has a strong effect on directional friction. At a texture density of 70 %, the friction coefficient in the CW direction increased by 28.1 % compared to the CCW direction. The greatest increase in friction coefficient, 61.3 %, was observed during CW rotation at the lowest texture density compared to the reference untextured surface.

Effect of surface texture on quality of stainless steel-PET transmission welding

Metal-plastic joints are widely used in industrial production. Laser lap welding using polyethylene terephthalate (PET) side can effectively connect 304 stainless steel to PET. However, there are still several issues in this transmission welding. In this study, the scanning speed and pulse frequency of laser were optimized for producing the best texture grooves. The influences of surface texture grooves on laser absorption and strength of 304 stainless steel/PET joints were then investigated. The obtained results showed that the scanning speed and pulse frequency of laser have a great influence on the width and depth of texture grooves. On the premise of ensuring the formation of quality of a groove, the depth of the groove can be allowed to reach 69 μm. In the laser absorption rate experiment, the deeper and narrower the grooves, the higher was the laser absorption rate. This was consistent with the simulation results of the temperature field. The average temperature in the melting zone of the textured surface was 15.27 % higher than that of the non-textured surface. After welding, the tensile strength of the textured material in the joint was 35.26 MPa, which was 4.67 MPa higher than that of the non-textured material. This also showed that the texture treatment of stainless steel surface can not only improve the laser absorption rate of the surface, but also provide a mechanical anchoring effect and improve the tensile strength. Compared with that under non-textured material, the tensile strength of textured material under low energy parameters was found higher, which was conducive to the high-strength connection between metal and plastic.

Experimental verification on the influence of surface texturing on biomaterials and study of its tribological characteristics

With the increased utilization of the surgical implants there has been a rise in the need for research in optimizing the wear resistance and enhancing its life expectancy. Artificial implants may possess surface texturing that acts as lubricating fluid reservoirs, trapping wear particles and increasing hydrodynamic pressure. As a result, the variation in dimple size and shape may significantly affect the tribological performance of the implants. Therefore, it is crucial to investigate how surface texturing affects biomaterials. A new surface texturing study on the biomaterials was proposed for enhancing the physical properties which was carried out in accordance with a theoretical analysis for understanding the distribution of stress in the textured surface of the implant. The present study focusses on 316L Stainless steel, Ultra High Molecular Weight Polyethylene (UHMWPE), Alumina, and Cobalt Chromium alloy (CoCrMo) biomaterials for experimentally verifying the effects of surface texturing. Texturing patterns were created using a laser texturing machine (Nd: YAG laser) and a pin-on-disc type machine was used to conduct wear tests on the textured and untextured components of the four biomaterials. Under typical load conditions of 70 N, friction coefficient and wear rate for the textured and untextured components of the four biomaterials were recorded. The impact of surface texturing on the tribological features was established based on the experimental findings. The test was supported by an ANSYS simulation study, which also depicts that there is a reduction in stress, which affects the coefficient of friction and eventually the wear. The Specific Wear Rate (SWR) revealed an average improvement of 59.85% between the untextured and the hexagonally textured biomaterials when compared to the results of the selected 4 biomaterials, while the Coefficient of Friction indicated an improvement of 82.66%. Thus, the laser texturing on the surface of the biological implant has a significance on the material’s property correlating to its longevity.

Machining investigation of textured tungsten carbide tools

Dry machining is viable substitute to the adverse effects of cutting fluids on the environment. However, dry machining increased adhesion and friction between the machining surfaces that leads to rise in surface temperature and hence the tool life gets reduced. To overcome this, the concept of texturing on tool surfaces was introduced. These textures were found to be efficient in reducing adhesion and friction between the machining surfaces. This ensued increase in tool life and decrease in tool wear. This paper presents the effect of surface textures (inclined, crossed and parallel) on the machining performance like material removal rate (MRR) and tool wear rate (TWR) of tungsten carbide tools. For this, the turning operations were performed in lathe machine following Taguchi’s L9 orthogonal array with three control factors and three levels each, viz. spindle speed (290, 480 and 700 rpm), feed rate (0.06, 0.14, 0.2 mm/rev) and depth of cut (0.2, 0.4, 0.6 mm). It has been observed that inclined textured tools have highest MRR followed by parallel and crossed textures, respectively. On the other hand, inclined textured tools have the lowest wear rate followed by crossed and parallel textured, respectively.

Improving dry machining performance of surface modified cutting tools through combined effect of texture and TiN-WS2 coating

In this research work, investigation on different surface modification techniques on cutting tools such as TiN-WS2 coating (T2), textured cutting tool (T3) and TiN-WS2 coated textured tool (T4) in dry machining of Ti-6Al-4V has been carried out and compared with commercial tool (T1). The presence of (002) orientation corresponding WS2 was observed in the diffraction pattern and this in turn was said to provide lubricity properties to the coatings. The cutting force generated during machining was reduced by 14 % for T4 tool when compared to T1. The T4 tool showed an increase in the shear angle by 7.5 % and decrease in coefficient of friction by 47 %. The prime mechanism attributed to the better performance of cutting tool was reduced tool-chip contact length. The T4 tools showed a 13 % reduction in tool-chip contact length when compared to commercial tools. The tool life of the T2, T3 and T4 tools was improved by 35 %, 29 % and 43 % respectively in comparison to commercial tools. The TiN-WS2 coatings, through its effective lubricity properties have said to nullify the effect of coating affinity between the tool and workpiece as evidenced by the absence of built-up edge on the tool rake face while machining using TiN-WS2 coated tool. The combined effect of TiN-WS2 coatings and surface textures have resulted in better machining characteristics, suggesting it as a suitable surface modification for dry machining of Ti-6Al-4V.

Fatigue performance and failure mechanism of ultrasonic-assisted abrasive-belt-ground Inconel 718

The fatigue performance and failure mechanism of ultrasonic-assisted abrasive belt grinding Inconel 718 surface was studied. The results showed that ultrasonic-assisted abrasive belt grinding improved the surface fatigue performance by 14.3–74.8%. A uniform grain plastic deformation layer formed on the grinding surface, which resulted in a mechanical property gradient. The surface material exhibited superior deformation adaptability, and the subsurface material had interface effects. Strain averaging caused by the intermittent surface texture and interfacial effect caused by grains plastic deformation result in fatigue cracks on the subsurface. Consequently, plastic fracture characteristics appear near the fatigue source. Accordingly, a novel anti-fatigue grinding strategy was proposed.

Synergetic effects of surface textures with modified copper nanoparticles lubricant additives on the tribological properties of cylinder liner-piston ring

The cylinder liner-piston ring (CLPR) is one of the most critical frictional pair for energy conversion in diesel engines. In this study, two forms of surface texture were respectively prepared on the liner surface by laser processing, with the modified copper nanoparticles (CNP) applied as the lubricant additives. The reciprocating tribometer and accompanying tribological testing technologies were then used to explore the synergetic effects of surface textures and additives on the tribological properties of CLPR. The results show that the composite lubrication system exhibits good friction-reduction and wear-resistance as the appropriate texture was adopted. Additionally, the synergetic effects among the storage capability of textures and the self-repairing ability of CNP additives can explain the improvement mechanism of CLPR’s tribological properties.

Frictional noise mitigation using synergetic approach of laser surface texturing and bio-lubrication

In this research study, the effect of laser surface texturing on friction induced noise under dry and lubricated sliding is investigated. Disc samples of EN 31 steel were ablated with dimples of 70 µm with varying pitch. The tribo-tests were conducted in anechoic chamber at a constant normal load of 10 N and frictional noise was studied in relation to sliding frequency and dimple pitch. Textured surfaces with 150 µm dimple pitch reduced friction and noise in lubricated conditions. FESEM and EDS were used to analyze the worn surfaces. Taguchi integrated Grey analysis revealed that optimal average frictional noise and COF are obtained under lubricated conditions with 10 Hz sliding frequency and 150 µm dimple pitch.