Surface Of Metallic Materials Research Articles

A Defect Detection Method for the Surface of Metal Materials Based on an Adaptive Ultrasound Pulse Excitation Device and Infrared Thermal Imaging Technology

Ultrasonic excitation has been widely used in the detection of microcracks on metal surfaces, but there are problems such as poor excitation effect of ultrasonic pulse, long time to reach the best excitation, and difficult to find microcracks. In this paper, an adaptive ultrasonic pulse excitation device and infrared thermal imaging technology have been combined, as well as their control method, to solve the problem. The adaptive ultrasonic pulse excitation device adds intelligent modules to realize automatic adjustment of detection parameters, which can quickly obtain reliable excitation; the multidegree-of-freedom base realizes the three-dimensional direction change of the ultrasonic gun to adapt to different excitation occasions. When the appropriate ultrasonic excitation makes microcracks in the resonance state, the microcracks can be frictionated, which produce heat rise with the temperature. Then, the microcrack defect can be detected by the infrared thermal instrument through the different surface temperatures with imaging recognition method. Our detection experiments of the titanium alloy plates and the aluminum alloy profiles of marine engineering show that the method can get reliable detection parameters in a short time and measure the crack length effectively. It can be used in many aspects such as crack detection in mechanical structures or complex equipment operating conditions and industrial production processes.

Femtosecond Laser-Pulse-Induced Surface Cleavage of Zinc Oxide Substrate.

The induction of surface cleavage along the crystalline structure of a zinc oxide substrate (plane orientation: 0001) by femtosecond laser pulses (wavelength: 1030 nm) has been reported; a scanning electron microscope image of the one-pulse (pulse energy: 6–60 μJ) irradiated surface shows very clear marks from broken hexagons. This cleavage process differs from the general laser-induced melt process observed on the surfaces of narrower-bandgap semiconductors and other metal materials. This phenomenon is discussed using a multi-photon absorption model, and the pulse-energy dependence of the cleavage depth (less than 3 μm) is quantitatively analyzed. Laser-induced cleavage is found not to occur under multi-pulse irradiation; when more than four pulses are irradiated upon the same spot, the general laser-induced melt process becomes dominant. This cleavage–melt shift is considered to be caused by the enhancement of absorption due to the initial pulses, which is supported by our measurement of cathodoluminescence.

Novel dental implant modifications with two-staged double benefits for preventing infection and promoting osseointegration in vivo and in vitro

Peri-implantitis are a major problem causing implant failure these days. Accordingly, anti-infection during the early stage and subsequent promotion of osseointegration are two main key factors to solve this issue. Micro-arc oxidation (MAO) treatment is a way to form an oxidation film on the surface of metallic materials. The method shows good osteogenic properties but weak antibacterial effect. Therefore, we developed combined strategies to combat severe peri-implantitis, which included the use of a novel compound, PD, comprising dendrimers poly(amidoamine) (PAMAM) loading dimethylaminododecyl methacrylate (DMADDM) as well as MAO treatment. Here, we explored the chemical properties of the novel compound PD, and proved that this compound was successfully synthesized, with the loading efficiency and encapsulation efficiency of 23.91% and 31.42%, respectively. We further report the two-stage double benefits capability of PD + MAO: (1) in the first stage, PD + MAO could decrease the adherence and development of biofilms by releasing DMADDM in the highly infected first stage after implant surgery both in vitro and in vivo; (2) in the second stage, PD + MAO indicated mighty anti-infection and osteoconductive characteristics in a rat model of peri-implantitis in vivo. This study first reports the two-staged, double benefits of PD + MAO, and demonstrates its potential in clinical applications for inhibiting peri-implantitis, especially in patients with severe infection risk.

Evaluation of Mechanical Characteristics of Tribofilm Formed on the Surface of Metal Material Due to Friction under Lubrication with Automatic Transmission Fluid

Evaluation of Mechanical Characteristics of Tribofilm Formed on the Surface of Metal Material Due to Friction under Lubrication with Automatic Transmission Fluid

Adhesion of various dental luting cements to the mirror-polished surface of metallic dental materials

本研究の目的は，鏡面研磨されたJIS2 種チタン表面に対する各種市販合着用セメントの引張接着強さを検討し，金銀パラジウム合金および金合金への引張接着強さと比較することである．3 種類の歯冠修復用合金・金属（JIS 第2 種鋳造用チタン12％金銀パラジウム合金，およびタイプ3 金合金）平坦面を鏡面研磨し，表面処理後に合着用コンポジットレジンセメント（パナビア®V5），コンポジット系接着性レジンセメント（リライエックスTM アルティメット），4-META / MMA-TBB 系接着性レジンセメント（スーパーボンド®），合着用従来型グラスアイオノマーセメント（ハイ－ボンドグラスアイオノマーCX）のいずれかを用いてステンレス棒を接着した．なお表面処理にはパナビアV5 の場合ではクリアフィル® セラミックプライマープラスまたはアロイプライマーのいずれかを， リライエックスTM アルティメットではスコッチボンドTM ユニバーサルアドヒーシブを，スーパーボンドではV- プライマーをそれぞれ塗布した．またチタン鏡面研磨面ではスーパーボンドの応用方法の相違についても検討した．12％金銀パラジウム合金の場合，V- プライマー/ スーパーボンドでの接着が最も高い接着強さを示した．タイプ3 金合金の場合においてもV- プライマー/ スーパーボンドでの接着で最も高い接着強さを示したが，その値は12％金銀パラジウム合金の場合よりも大幅に低いものであった．JIS2 種純チタンの場合，スーパーボンド使用時に被着面に対してあらかじめ活性化液（クイックモノマー（5％ 4-META + 95％ MMA）とキャタリストV（TBB-O）の混合液）を塗布した場合に接着強さの向上を認めた．本研究結果から，鏡面研磨された歯冠修復用合金・金属に対する金属用プライマー/ 合着用セメントの効果は金属材料の種類に依存すると結論付けられた．【顎咬合誌 40（ 3 ）：219-230，2020】

The Ceramic Composite Coating (TiC+TiB2) by ESD on Ti6AL4V Alloy and Its Characterization

Titanium based alloys or materials used for mechanical and constructional purposes can exhibit high corrosion and abrasion resistance with coatings made on their surfaces. In this study, the surface of Ti6Al4V plate substrate was coated with TiC+TiB2 composite electrodes at different volts and frequencies by Electro-Spark Deposition (ESD) method. The ESD method is a micro arc welding method that allows deposits of alloys and ceramics compounds that have electrical conductivity on the surface of metallic materials, with the plasma that brings about a better melting of base metal and electrode for producing good adhesion between the coating and base metal. In this study, the Ti6Al4V samples were coated with TiC+TiB2 electrodes, and the precoating, post-coating hardnesses, wear rates and coating layer thicknesses of the samples were examined. TiC + TiB2 composite coating on the surface of Ti6Al4V alloys by ESD method was achieved and the hardness increase was observed with the help of numerous hard ceramic phases.

Rational designed structured superhydrophobic iron oxide surface towards sustainable anti-corrosion and self-cleaning

Abstract A hierarchical micro-/nanostructure, consisting of nano-sized Fe2O3 needles vertically grown on the {1 1 1} facets of micro-octahedral Fe3O4 particles, has been successfully prepared on the surface of N80 steel using hydrothermal treatment followed by annealing. The nanoneedles were transformed from nanoparticles on the micro-octahedral facets under the influence of mixed acetone and acetic acid gas atmosphere, and the length of nanoneedles can be controlled by the annealing time. The superhydrophobic Fe2O3/Fe3O4 composite surface with water contact angle (WCA) of 157.3° and sliding angle (SA) of 8.1° was obtained after decorated with stearic acid. The influence of the annealing time on the surface morphology and hydrophobicity was explored and optimized. The superhydrophobic surface displays great self-cleaning and anti-corrosion performances with good mechanical robustness. This method opens a new venue towards preparing micro-nanostructures on the surface of metallic materials for enhanced anti-corrosion and self-cleaning applications.

Mechanical Tests Results of Laser Shock Peening-Treated Austenitic Steel

Abstract The presented paper is focused on laser shock-peening technology for hardening the metallic material surface. The material surface hardening improve fatigue performance, static properties, and resistance to stress corrosion cracking of metallic material, which is achieved by creating a pressure residual stress with. The hardening is achieved by shock waves, which are generated by confining the laser-induced plasma to cause a large pressure shock wave over a significant surface area. In the present study, effects of laser shock peening (LSP) on static and dynamic mechanical properties of austenitic stainless steel for nuclear industry were investigated. The tested material was austenitic stainless steel GOST 08CH18N10T (AISI 321H-UNS S32109) for nuclear industry (water–water energetic reactors).

Pulsed Thermography Inspection of Composite Anticorrosive Coatings: Defect Detection and Analysis of Their Thermal Behavior through Computational Simulation.

The use of anticorrosive coatings has been a powerful method to be applied on the surface of metallic materials to mitigate the corrosive process. In this study, the focus is composite coatings that are commonly used on the internal surface of storage tanks in petrochemical industries. The development of non-destructive methods for inspection of faults in this field is desired due to unhealthy access and mainly because undercoating corrosion is difficult to detect by visual inspection. Pulsed thermography (PT) was employed to detect undercoating corrosion and adhesion loss of anticorrosive composite coatings defects. Additionally, a computational simulation model was developed to complement the PT tests. According to the experimental results, PT was able to detect all types of defects evaluated. The results obtained by computational simulation were compared with experimental ones. Good correlation (similarity) was verified, regarding both the defect detection and thermal behavior, validating the developed model. Additionally, by reconstructing the thermal behavior according to the defect parameters evaluated in the study, it was estimated the limit of the remaining thickness of the defect for which it would be possible to obtain its detection using the pulsed modality.

Constructing Colorful Surfaces with Mechanical Robustness for Magnesium Alloys via a Reagent-Free Method.

The colorful and mechanically robust surfaces of metallic materials are important for their applications in electronics, automobile, aerospace, and so on, but it is challenging to prepare them at a reasonable cost. Herein, we propose a simple, environment-friendly, and cost-effective method, reagent-free hydrothermal treatment, to prepare colorful surfaces of magnesium alloys with mechanical robustness. The as-treated surface mainly composes of magnesium (hydr)oxides with a biomimetic microstructure, whose thickness and roughness increase linearly with the hydrothermal time. By adjusting the hydrothermal time, a series of surface colors of magnesium alloys are obtained because of light interference. The as-treated surface with film thickness more than 1.1 μm exhibits high Vickers hardness (∼500 HV), low friction coefficient (∼0.26), and low wear rate (1.06 × 10-5 mm3·N-1·m-1), which is superior to most magnesium alloys after surface treatments. The microstructure of the as-treated surface can be retained after harsh tribological tests, demonstrating attractive mechanical robustness. Furthermore, the method proposed here was extended to the surface treatments of other series of magnesium alloys, which verifies the great potential of this method for large-scale industrial application of colorful metallic materials with mechanical robustness.

Testing a nano-barcodes marking technology for identification and protection of the mechanical products

The article presents a technology for application and identification of nano-barcodes on the surface of industrial products. The essence of this process is to modify the surface of metallic materials by exposure to pulsed laser radiation. As a result of such exposure, the modified surface contains small labels, allowing storing encoded information directly on the machine part, bypassing intermediate carriers. The laser-applied labels are formed using software and encode informative data. The encoding of the input information ensures the uniqueness of the applied nano-barcodes. The proposed technology allows us to apply such unique labels on the materials surface for accounting and identification of industrial products. The proposed marking technology allows us to place a significant amount of information in a small area. Special software has been developed for decoding the information from the applied nano-barcode developed. Studies have been performed that have been conducted to determine the thickness of the marked symbols formed on the materials surfaces and the reliability of the applied symbols. There are also recommendations on the usage of the technology given for direct labeling of materials with the application of information with high recording density for various industries.

Tribological Behavior of a Self-Lubricant Surface Film of H<sub>3</sub>BO<sub>3 </sub>Formed on a Borided Biomedical Steel by a Post-Treatment

This paper evaluates the tribological behavior of borided AISI 316L steel after being exposed to a secondary process to form a thin film of a solid lubricant. The process known as Short Annealing Process (SAP), allows creating a thin film of boric acid (H3BO3) on the surface of metallic materials previously exposed to boriding. The H3BO3 film acts like solid lubricant due to its lamellar crystalline structure. First samples of AISI 316L were exposed to boriding to temperatures of 875, 925 and 975 °C during 2, 4 and 6 h each temperature. Then, samples were heated to 750 °C during 5 min and cooled to room temperature at 60 % of Relative Humidity. The tribological behavior of the treated samples was evaluated by pin-on-disk test equipped with friction coefficient measurement system. Samples were characterized by Scanning Electron Microscopy, X-Ray Diffraction and Vickers microhardness test. The results showed an evident influence of the experimental parameters on the thickness of the boride layers and their mechanical properties. The layer ́s thickness was ranged from 10.51±0.71 to 51.57±5.12 μm. The hardness of the coatings was increased from 264 to 1685 HV. Finally, the Coefficient of Friction was diminished from values of 0.7 for the as-received material to 0.29 for the borided samples and to 0.06 for those after SAP, which indicates that the post-treatment SAP enhances the tribological properties of the biomedical steel.

The New Technologies Developed from Laser Shock Processing.

Laser shock processing (LSP) is an advanced material surface hardening technology that can significantly improve mechanical properties and extend service life by using the stress effect generated by laser-induced plasma shock waves, which has been increasingly applied in the processing fields of metallic materials and alloys. With the rapidly development of modern industry, many new technologies developed from LSP have emerged, which broadens the application of LSP and enriches its technical theory. In this work, the technical theory of LSP was summarized, which consists of the fundamental principle of LSP and the laser-induced plasma shock wave. The new technologies, developed from LSP, are introduced in detail from the aspect of laser shock forming (LSF), warm laser shock processing (WLSP), laser shock marking (LSM) and laser shock imprinting (LSI). The common feature of LSP and these new technologies developed from LSP is the utilization of the laser-generated stress effects rather than the laser thermal effect. LSF is utilized to modify the curvature of metal sheet through the laser-induced high dynamic loading. The material strength and the stability of residual stress and micro-structures by WLSP treatment are higher than that by LSP treatment, due to WLSP combining the advantages of LSP, dynamic strain aging (DSA) and dynamic precipitation (DP). LSM is an effective method to obtain the visualized marks on the surface of metallic materials or alloys, and its critical aspect is the preparation of the absorbing layer with a designed shape and suitable thickness. At the high strain rates induced by LSP, LSI has the ability to complete the direct imprinting over the large-scale ultrasmooth complex 3D nanostructures arrays on the surface of crystalline metals. This work has important reference value and guiding significance for researchers to further understand the LSP theory and the new technologies developed from LSP.

The influence of low energy titanium ion beam irradiation on secondary electron emission of metal materials by electron impact

Argon ion beams with energy from hundreds eV to several keV can suppress the secondary electron emission (SEE) on surface of metal materials by changing surface morphology and chemical composition of the materials through surface sputtering. In this work, it was found that the low-energy titanium ion irradiation with an average energy from 40 keV to 100 keV did not apparently change the surface morphology and chemical composition of the metal materials, but still significantly reduced the secondary electron yield (SEY) of the materials. Pulsed titanium ion beams generated by an ion implanter, which is based on metal evaporation vacuum arc (MEVVA) ion source, were adopted to irradiate oxygen-free copper and stainless-steel samples. The fluence of titanium ions was in the range of 1 × 1015 to 1 × 1017 ions/cm2. By comparing the effects of different titanium ion energies and fluence on the roughness, chemical composition, total SEY of the sample surface, and calculating the ion range, sputtering yield, nuclear stopping power and defect distribution of titanium ions in these materials, it is reasonable to believe that the irradiation damage caused by titanium ion implantation increases the probability of trapping of the low-energy secondary electrons (SEs) by defects, leading to better SEE suppressing.

Metal material surface wettability increase induced by electron beam irradiation

Surface wettability is one of the important metal surface characteristics which would affect boiling heat transfer performance of metal surfaces. In this study, different metal surfaces are irradiated by electron beam to investigate whether the surface wettability of metal surfaces can be increased by electron beam irradiation. The experimental results show that electron beam irradiation can greatly improve the surface wettability of various metal surfaces. The surface wettability of all surfaces increase as irradiation dose increase and some metal surfaces become quite hydrophilic when the irradiation dose reaches 3000 kGy. Besides, electron beam irradiation shows better effect on increasing the surface wettability of pre-oxidized metal surfaces. The results are discussed and analyzed considering the characteristics of oxidation porous layer. This finding shows that electron beam irradiation could be an effective way to increase the metal surface wettability and study the effect of surface wettability increase on boiling heat transfer.

The distribution regularity of residual stress on a metal surface after laser shock marking

A metal material surface marking method was developed based on the theory that a larger thickness of the absorption layer can attenuate a laser-induced shock wave. The introduction of surface residual compressive stress is the main feature of this new marking method, which is different from the traditional mechanical processing marking method and is also the key factor leading to the good service performance of the metal material surface. After the laser shock marking (LSM) treatment, the residual stress at different positions on the metal surface was measured, and the change in distribution trend of residual stress and microstructure in the laser shock-treated region was discussed. The results show that for two different marking patterns, the expected deformation areas have a remarkable residual compressive stress distribution, and the relatively large full width at half maximum (FWHM) of the X-ray diffraction peak of the expected deformation areas characterizes significant microstructure changes. The microstructure of the edge region of the formed mark shows a sudden change, while the residual stress changes gradually. This change indicates that the surface's severe plastic deformation is directly related to microstructure changes and indirectly related to residual stress changes.

Способ определения износостойкости и глубины износа тонкослойных функциональных покрытий

The surface of metallic materials in friction pairs is protected from contact interaction by applying functional coatings. The minimum loads set in standard friction machines can be critical and instantly abrade the modified surface. Consequently, new promising approaches are needed in the development of coating diagnostics. This paper presents the approbation of a new promising method for evaluating thin-layer coatings based on the acoustic emission method using a reference sample.

New Combination of Magnet and Coil of Electromagnetic Acoustic Transducer for Generating and Detecting Rayleigh Wave.

Nondestructive testing for identifying defects on the surface of metal materials is important for industries and infrastructures. The Rayleigh wave is widely used for detecting these surface defects. For replacing piezoelectric transducers with electromagnetic acoustic transducers (EMATs) for the surface inspection of metal materials, this article proposes a new magnet and coil combination consisting of a periodic-permanent-magnet (PPM) and a returned dislocation meander line coil. The returned dislocation meander line coil was developed using a traditional meander line coil, whose wires return from one side to another and shift for a certain distance. A 2-D finite-element simulation was conducted to analyze the performance of the proposed Rayleigh wave EMAT. The simulation results revealed that, compared with a large conventional magnet, the PPM increased the maximum magnetic flux density, and made the magnetic flux density distribution more concentrated on the specimen's surface, particularly below the coil. In the middle part of the coil, the PPM greatly increased the intensity of the horizontal magnetic field. Additionally, the returned dislocation meander line coil made full use of the strong magnetic field below the center of each small magnet and at the adjacent magnets. The designed Rayleigh wave EMAT was fabricated, and the experimental results revealed that the new design of the Rayleigh wave EMAT increased the received signal by 57.9% compared with the conventional Rayleigh wave EMAT.

Metallurgical and material properties correlations between machined and severely plastic deformed aluminium alloy

The possibility to study and clearly define the physics phenomena that occur during the machining process of various metal materials is becoming one of the interpretative keys to quantify a product’s quality and life cycle performance. An accurate understanding of the surface integrity can be achieved through the knowledge of the fundamental details about the mechanical response and the behaviour of the affected material layers caused by thermo-mechanical loads induced by machining operations. Therefore, this set of information can help the designer to produce parts with superior quality. The aim of this work is to study the surface layer states in terms of metallurgical and mechanical properties of aluminium alloy 7075 in a machined and a sereverely plastic deformed by the Equal Channel Angular Pressing (ECAP) process. The outcomes provided by the experimental measurements permitted to find possible links regarding the microstructural and hardness changes observed between the machined surface layer and the region of material deformed by ECAP. Finally, this scientific investigation aims to establish the basis for an innovative method to study and quantify the metallurgical phenomena that occur beneath the machined surface of bulk metal materials.

Determination of electrode potentials on local metals surfaces and welded joints

A method and installation for measuring electrode potentials on the local areas of metal surfaces and welded joints are developed. The special of the method and design of the installation is the supply of electrolyte to the metal surface due to the capillary effect of the wick made of fiber material. A gold wire was chosen as a reference electrode. Combination of the capillary supply of the electrolyte and electrode of small diameter provides measuring of the electrode potentials on rather small (up to structural components) surface areas. Change in the electrode position and electrode potential recorded in continuos mode can be visualized and scaled-up on a computer display. The developed procedure provides determination of the electrode potentials on the surfaces of metal materials with electrochemical heterogeneity and can be used to assess the corrosion resistance of materials; electrochemical heterogeneity of the structural components; forecast the service life of the metal structures; simulate the technologies of welding and soldering steel with metal corrosion coatings with a minimal damage to the protective coating and determine the corrosion properties of the products in service to predict their residual life.