Surface Of Metallic Materials Research Articles

Research on metal surface specular removal algorithm based on unsupervised learning

The highlights on the surface of metal materials can seriously destroy the continuity of the image, produce certain false edges, and cause the texture details in the highlights area to weaken or even disappear, which interferes with the subsequent operations such as surface region segmentation and defect detection. Aiming at the low efficiency, high loss, easy distortion and difficult calibration of metal highlight data, an unsupervised perceptual enhancement network model based on the convolutional neural network (CNN) is proposed. Firstly, the method of generating antagonism is used to generate a large number of metal images with high-light feature information, which is used to increase the number of high-light metal image data sets in the training set. Secondly, a detail enhance model(DEM) and a color enhance model(CEM) are introduced into the context aggregation network to improve the feature detail retention rate in the low resolution weight graphs. Finally, the multi-scale structural similarity function is used to replace the original structural similarity function to solve the insensitive detail when the image size is too large. Experiments show that comparing with other multi-exposure image fusion models, the present model can improve the evaluation index of mutual information and average gradient of fused images by about 10%, and can retain more texture feature information.

Influence of Corrosion on Thermo-Mechanical Contact Fatigue in Rolling Conditions with Low Amplitude Sliding

The paper presents some aspects concerning mechanical contact fatigue and corrosion wear and the links of these two kinds of wear in the common deterioration of the contact layer. The surface state, for both presented areas, is analyzed using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) in order to confirm the double action of corrosion and wear during the experimental test. 2 and 3D insights were taken from the worn area, corrosion compounds were identified and analyzed. Linear and cyclic potentiometry were performed on the base materials after the OCP was established in salt solution. When the level of the thermal and the mechanical stress are located at the same depth under the contact surface the resulting stress is greater and has the opportunity to develop the first crack to the surface. The metallic material surface presents a double type of corrosion: one based on oxidation and the other one based on oxidation plus wear (tribo-corrosion), the difference is being given by the material quantity and type involved.

Magneto-acoustic Fusion Sensing for Surface and Subsurface Defect Differentiation in the Ferromagnetic Material

The conventional periodic permanent magnet (PPM) shear horizontal (SH0) guided wave electromagnetic acoustic transducer (EMAT) has a good detection capability for defects on both the surface and subsurface of the material. However, it is difficult to distinguish between surface and subsurface defects in the material using only the amplitude of the defect echo. In this paper, SH0 guided wave is excited using the SH0 guided wave EMAT with PPM configuration, which is used to achieve the detection and evaluation of defects on the surface and subsurface of ferromagnetic metal; on the other hand, the local magnetic field perturbation (MFP) effect of the PPM configuration on ferromagnetic material is fully exploited to achieve the identification of surface defects by picking up the MFP of the material at the defects. The proposed magneto-acoustic fusion effect sensor has an improved spatial magnetic field at both the mechanical construction and the magnetic sensor compared to the traditional magnetic flux leakage (MFL) detection method. Both simulation and experiment show that the proposed magneto- acoustic fusion effect sensing method based on the PPM configuration is capable of detecting the defects on the surface and subsurface of metal material, while the MFP effect in the fusion sensor can be used to help differentiate between the surface and subsurface defects in the material.

A REVIEW OF PREDICTIVE MAINTENANCE APPROACHES FOR CORROSION DETECTION AND MAINTENANCE OF MARINE STRUCTURES

Corrosion is a natural phenomenon that deteriorates and damages the surface of metallic material. Over time, the surface of the material deteriorates due to electrochemical reactions with the surrounding environment. If corrosion is not identified early on, it can become a major financial burden for industries, costing billions of dollars. Despite swift technological developments, preventing and maintaining corrosion progression with reactive maintenance remains difficult. Due to that, predictive maintenance has been developed to predict the deterioration, degradation, and fault over the remaining useful life of the material by using real-time data, historical data, simulation, modelling, and failure probability. Predictive maintenance allows inspectors to monitor the health and predict the corrosion level of the material. However, it is hard to predict the unexpected degradation of the material from the developed prediction model without considering the harsh environment and other external factors. Hence, there is a need to investigate these problems and their effect on predictive maintenance for corrosion detection and maintenance. Therefore, this paper reviews and compares the state-of-the-art predictive maintenance solutions developed to solve corrosion issues in various applications, industries, and academic research. The challenges and opportunities for the predictive maintenance application of corrosion detection and maintenance are also presented. This review will provide new and additional knowledge that can be used to develop prediction models for corrosion detection and maintenance, which will help prevent unexpected failures.

Review on numerical simulation of ultrasonic impact treatment (UIT): Present situation and prospect

Ultrasonic Impact Treatment (UIT) is a surface treatment method that uses ultrasound to create high-frequency, high-intensity impact loads on the surface of metallic materials to improve material properties and durability. The current state of research on the numerical simulation of UIT is reviewed in this paper. Firstly, the working principle of UIT strengthening is introduced, which includes the application of high-intensity UIT to the surface of metallic materials. The UIT strengthening technology has achieved significant success in the industrial field, resulting in plastic deformation, surface compression and residual stress, thereby significantly improving material properties. Secondly, the influence of UIT on the microstructure is reviewed. It is found that the grain refinement and dislocation are successfully predicted by finite element simulation and other methods. The influence of UIT on residual stress is reviewed. It is found that UIT can effectively transform harmful tensile stress into compressive stress, and it has been found that it can be used to guide the industrial practice of welding, laser cladding and additive manufacturing. In general, UIT technology shows important potential in metal material processing, which is of great significance for improving material properties and promoting industrial practice.

Investigation and analysis of a sustainable agro-based nanocoating on surface of metallic materials

In this study, nanotechnology was used to develop a coating from agricultural waste. Banana peels underwent various chemical processes, nanoparticles were developed and tests were conducted to validate it. The metal samples used for coating application were made of mild steel which is used to produce a large percentage of metal parts in the industry and was selected for this research project due to that reason. The metals were cut into 50 mm x 50 mm and 50 mm x 30 mm. The sample coatings included a control coating which was used as the yardstick to know the effects of the nano coating applied which contained various concentrations of nanoparticles showed results that were more favorable than the coatings that were applied without nanoparticles contained in them. Qualitative analysis of the coated metal samples A to G showed that sample E which had 7.24 grams of nanoparticles contained in it had the highest amount of hardness while sample A which was control coating possessed the least hardness amount. The abrasion test of the samples revealed that sample D which had 21.72 grams of nanoparticles contained in it possessed the highest weight of coating before and after the abrasion test

Wear and corrosion behavior of TiC and WC coatings deposited on high-speed steels by electro-spark deposition

Abstract Electro-spark deposition (ESD) is one of the most effective methods for improving the surfaces of metallic materials by applying ceramic-based cermet coatings. In this study, TiC and WC coatings were deposited on the surface of AISI M2 high-speed steel using the ESD method. Subsequently, the coated surfaces were examined through microstructure, phase structure, microhardness, friction, wear, and electrochemical corrosion tests, and compared with untreated AISI M2 steel. The TiC and WC phase coatings obtained with ESD resulted in a significant improvement, with hardness levels exceeding four times that of AISI M2 steel, leading to reduced wear volume losses and friction coefficients. Furthermore, the cermet coatings formed on the surface exhibited 2–3 times improvement in corrosion resistance due to their lower conductivity. This study demonstrates that WC coatings may offer a more effective solution for enhancing the wear resistance of AISI M2 steel, while TiC coatings could be more effective in improving corrosion resistance.

Study on the properties of sodium bismuth titanate coating prepared by supersonic plasma spraying

In order to realize the preparation of environmentally friendly piezoelectric ceramic coatings on the surface of metallic materials, sodium bismuth titanate (Bi0.5Na0.5TiO3, BNT) ceramic coatings were prepared by supersonic plasma spraying. The surface morphology, cross-sectional morphology, phase structure, and elemental valence variations of the BNT coating were examined, as well as the dielectric and ferroelectric properties of the BNT coating. The results show that the coating has a good quality and a single perovskite structure. The dielectric constant was stable at about 425 and the dielectric loss was stable at about 0.06 when the test frequency reached 200 kHz. The coating exhibits good hysteresis lines under different applied electric fields. When the applied electric field was 40 kV/cm, the remnant polarization value of the prepared coating was 11.47 µC/cm2. It can be seen that the BNT piezoelectric coating prepared by supersonic plasma spraying has good ferroelectric and dielectric properties, which lays a solid foundation for in-situ monitoring of environmentally friendly lead-free BNT piezoelectric coating.

Surface Protection Technology for Metallic Materials in Marine Environments.

As the demand for the development and utilization of marine resources continues to strengthen, the service requirements for advanced marine equipment are rapidly increasing. Surface protection technology has become an important way of solving the tribological problems of extreme operating conditions and improving the safety performance of equipment by imparting certain special properties to the surface of the material through physical, chemical or mechanical processes to enhance the ability of the material to withstand external environmental factors. Combined with the extremely complex characteristics of the marine environment, this paper describes the commonly used surface protection technologies for metal materials in the marine environment. Research on surface texture was summarized under different surface reshaping technologies, as well as processes and coating materials under different surface modification technologies. Combined with the existing research progress and development trends of marine metallic materials, the surfaces of metal materials under the marine environment protection technology foreground are prospected and provide a reference for the improvement of equipment performance in extreme marine environments.

Removal mechanism of Hydroides fouling on high-strength steel in the marine environment during nanosecond pulsed laser cleaning

The surface of metal materials will be contaminated by marine organisms when serving in the marine environment, which seriously affects the service life of the materials, and must be cleaned regularly. The Hydroides fouling on the surface of 30Cr3 high-strength steel was taken as the object to be cleaned; the cleaning quality at different laser fluences was studied; the desorption behavior and the characteristics of spectral and acoustic signals during laser cleaning were analyzed; and the removal mechanism of Hydroides fouling on the surface of high-strength steel was summarized. The results show that the cleaning effect of nanosecond pulsed laser on Hydroides fouling increases with the increase of laser fluence, and the laser fluence of 9.95 J/cm2 can be used to clean the Hydroides fouling with the maximum diameter of 1.62 mm completely with little damage to the substrate. The removal mechanism of Hydroides fouling is the inverse bremsstrahlung mechanism. In the process of cleaning, the surface fouling is partially vaporized and ionized into high-temperature plasma under the action of pulsed laser. The laser energy is absorbed through inverse bremsstrahlung absorption to form shock waves to compress the surface, which leads to cracks on Hydroides fouling. When the surface compressive stress is released, the Hydroides fouling is removed from the surface, and the removal effect increases with the increase of laser fluence.

Depth-resolved and time-resolved investigations of Er2O3 ceramics after static lithium corrosion by using LIBS at different pressures

Liquid metal lithium can cause severe corrosion on the surface of fusion reactor blankets and first-wall metal materials. Oxidized erbium ceramic has been widely studied as a candidate material for the self-cooling blanket system of tokamak fusion reactors. In this study, time-resolved picosecond laser-induced breakdown spectroscopy (ps-LIBS) was used to investigate the time evolution process of laser-induced plasma (LIP) of Er2O3 samples in air at different pressures. The pressure-time windows with high signal-to-background ratio and high signal-to-noise ratio under LTE conditions were determined. The composition depth distribution of the Er2O3 ceramic after static corrosion by lithium was analyzed. The number of laser pulses were linearly proportional to the laser ablation depth as measured by a three-dimensional profilometer. As the number of pulses increased, the relative intensities of the 610.353 nm and 812.645 nm characteristic lines of the corroding element Li gradually decreased, while the relative intensities of the 405.547 nm and 405.951 nm characteristic lines of the base element Er gradually increased. The laser pulse number at which the relative peak intensities of Er and Li reached a steady state showed a trend of first increasing and then decreasing with increasing pressure. In addition, the results of laser ablation depth under different environmental pressures indicated that the depth resolution of the analysis of anti-corrosion Er2O3 ceramic materials can be controlled by the environmental gas pressure.

SCPNet-based correction of distorted multi-spots for three-dimensional surface measurement of metal cylindrical shaft parts.

Metal cylindrical shaft parts are critical components in industrial manufacturing that require high standards for roundness error and surface roughness. When using the self-developed multi-beam angle sensor (MBAS) to detect metal cylindrical shaft parts, the distorted multi-spots degrade the measurement accuracy due to the nonlinear distortion caused by the metal material's reflective properties and surface roughness. In this study, we propose a spot coordinate prediction network (SCPNet), which is a deep-learning neural network designed to predict spot coordinates, in combination with Hough circle detection for localization. The singular value decomposition (SVD) model is employed to eliminate the tilt error to achieve high-precision, three-dimensional (3D) surface reconstruction of metal cylindrical shaft parts. The experimental results demonstrate that SCPNet can effectively correct distorted multi-spots, with an average error of the spot center of 0.0612 pixels for ten points. The proposed method was employed to measure metal cylindrical shaft parts with radii of 10 mm, 20 mm, 35 mm, and 50 mm, with resulting standard deviation (STD) values of 0.0022 µm, 0.0026 µm, 0.0028 µm, and 0.0036 µm, respectively.

Structural and mechanical properties of magnetron-sputtering-deposited Ta- and Al- based coatings – a comparative analysis

A comprehensive evaluation of the structure and the nano-mechanical characteristics of single and two-layer nano-structured coatings AlN/Al2O3, TaN/Ta2O5 grown on the surface of metallic materials. The formation of a two-layer structure improves the mechanical and tribological properties of the coating-substrate system, such as the plastic deformation resistance and anti-wear performance. The results indicate that the proposed two-layer nanostructured nitride-oxide coatings based on aluminum and tantalum are promising candidates for biomedical applications.

Role of length-scale in machine learning based image analysis of ductile fracture surfaces

Recent advancements in machine learning (ML) techniques have opened up new opportunities for using image analysis to solve materials science and engineering problems. In this work, we have used an ML-based workflow to classify the fracture surfaces of dual-phase steels subjected to different stress states. This task is not straightforward, as the ductile fracture surfaces of many metallic materials exhibit similar features, such as dimples. The ML-based workflow uses a pre-trained convolution neural network in unsupervised mode to extract image features, which are then reduced in dimensionality using principal component analysis. Next, images are clustered and classified using K-Means and K-Nearest Neighbors algorithms, respectively. Our results show that the accuracy of the ML-based technique is sensitive to the length-scales of the fracture surface images, and the critical length-scale corresponding to the maximum accuracy depends on the typological categories being classified. A physical interpretation of the critical length-scales associated with the fracture surface images is provided through quantitative fracture surface roughness analysis. Our work demonstrates the potential of using unsupervised ML-based techniques for fractography of ductile materials, especially for typological classification. More importantly, it emphasizes the importance of length-scales in image analysis in materials science and engineering.

Laser Shock Wave Surface Processing Possibilities of Structural Materials

Laser shock wave treatment is a newest effective tool for modifying material properties. Irradiation of materials with a laser in the Q-switched mode in different mediums can change the relief and surface structure of the irradiated material. Images of the surfaces of metallic materials under different irradiation conditions were obtained with the help of a scanning electron microscope. It is shown that the energy of the laser pulse and the transparent condensed medium through which the processing is carried out play an important role on the surface structuring. The possible causes of periodic relief are explained.

A radiative cooling, anti‐corrosion multifunctional composite coating derived from Jatropha (Jatropha curcas L.) oil

AbstractHere, a new application from Jatropha (Jatropha curcas L.) oil was successfully proposed to develop a multifunctional composite coating using Jatropha oil (JO) as a raw material to replace traditional non‐renewable chemical materials. Here, a new application of Jatropha oil is proposed to develop a multifunctional composite coating using Jatropha oil as a raw material instead of traditional non‐renewable chemical materials. To achieve this goal, Jatropha oil first needs to be made into refined Jatropha oil (RJO) by degumming, deacidification, decolorization, and deodorization. The RJO was then subjected to epoxidation to obtain epoxidized Jatropha oil (EJO), and the optimal epoxidation conditions were explored. Finally, EJO was synthesized as acrylate and barium sulfate (BaSO4) was added as inorganic filler to prepare a composite coating. The results showed that the thermal decomposition temperature of the composite coating was as high as 451°C, and the composite coating showed the best mechanical properties when the filling amount of BaSO4 reached 40%. The composite coating has a reflectivity of over 80% in the UV region and can reach a contact angle of 108 ° with excellent hydrophobicity, which can play a self‐cleaning role. In addition, the composite coating is also immersed in acid and alkali solution for 30 days, it has less mass loss and shows excellent acid and alkali resistance, which can play the role of anti‐corrosion. The composite coating can be attached to the surface of wood, glass, metal, plastic, and other materials to provide protection for the materials, which has good application prospects. This pioneering work provides an opportunity to promote JO with depressed application market in industrial production.

Effect of Temper Rolling Reduction Ratio on Microhardness and Microstructure of DC04 Grade Sheet Material

With temper rolling, which is the final stage of the cold rolling manufacturing process, to the surface of sheet metal materials is transferred roughness with specially roughened rolls. In this study, microhardness and microstructural evolution occurring in the section along the thickness of DC04 grade sheet materials temper rolled with various reduction ratios were investigated. As a result, it was concluded that the microhardness distribution taken from the section along the thickness increases with the increase of reduction ratio and the microhardness distribution from the surface to the center in the section decreases. In the temper rolling process with a reduction ratio of 250 µm and 500 µm an increase of approximately 5% and 15% has occurred, respectively compared to before the temper rolling process. It was also concluded that with the increase in reduction ratio, the grains in the section along the thickness elongated and thinned on the surface and this change in the center compared to the regions close to the surface was less.

Numerical study on the surface morphology evolution and hardness during the spherical indentation of copper with plastic behavior described by different stress-strain relationships

Spherical indentation on flat surfaces of metallic materials is a very simple and useful test for evaluating mechanical properties. FEM-based simulations have been extensively employed to study pile-up and sink-in effects during indentation process for materials which have plastic behavior described by Hollomon’s power law, where the strength coefficient K is calculated by the continuity condition. In the present numerical study, the stress-strain data of OFHC copper was fitted by three relationships: Voce, Hollomon and continuity-based Hollomon. Then sequential simulations of frictionless compression and ball-indentation tests were carried out, resulting in indentation load-depth curves of workpieces at different hardening levels. These load-depth curves were analyzed to determine the Meyer’s index, the pile-up/sink-in effects, and the Brinell Hardness of each workpiece. The results were compared to literature models and experimental data. The different mechanical behaviors of the Voce- and Hollomon-driven materials during indentation were explained on basis of competition between elastic and plastic deformations along the process. When using Voce’s relationship, the simulated Hardness Brinell curve agreed perfectly with experimental data obtained by Tabor (1951) for annealed and work-hardened copper, and the predicted sink-in for annealed copper agreed very well with experimental data from Campbell et al. (2018). The numerical and mathematical model proved be consistent and results indicate that plastic behavior of copper under indentation test is better described by the three-parameters Voce’s hardening law.

Research and Application of High-Velocity Oxygen Fuel Coatings

With the development of modern industrial technology, there is an increasingly urgent need for the preparation of high-strength and high-performance coatings on the surface of traditional metal materials [...]

A REVIEW OF THE ELECTRO-SPARK DEPOSITION TECHNOLOGY

Electro-spark deposition (ESD) technology is a new method for repairing and strengthening the surface of metal materials. This method has the advantages of simple equipment, convenient operation and wide application range. The alloyed coating has higher wear resistance, good corrosion resistance, excellent friction performance and other special properties, so it has better practical value and wide application prospect. This paper introduces the characteristics and principle of electro-spark deposition technology, analyzes the research status of this technology and points out the future development direction of this technology.