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In this study, the strain field evolution mechanism of laser-repaired 304 stainless steel /In718 heterogeneous structure was studied using EBSD technique. The results show that the strain concentration in the repaired zone is much smaller than that in the substrate zone. As the laser power increases from 900 W to 1100 W, the strain concentration in the repaired zone and the substrate zone increases significantly. The different strain concentration in the repaired region and the substrate region is mainly related to the increase of lattice distortion, dislocation density and temperature gradient. In addition, because the grains with different orientations have different Taylor factor, and therefore, grain orientation is also key factor affecting the strain concentration. [ABSTRACT FROM AUTHOR]

Metal oxide aerogels, inorganic cousins of the highly commercialized metalloid oxide silica aerogels, exhibit distinct properties specific to each type. Nevertheless, they share a common challenge with silica aerogels—brittleness and low mechanical strength due to their particulate necklace‐like structure. In contrast, polymer aerogels often boast significantly enhanced mechanical properties thanks to their nanofibrillated networks. To enhance the mechanical properties of metal oxide aerogels, the metal oxide formation with a polymeric nanostructure is micro‐templated. This method transforms the necklace‐like particulate microstructure of metal oxide aerogels (e.g., Al2O3 Cr2O3, and Fe2O3) into a polymer‐like nanobelt structure. Remarkably, even after removing the polymer template through calcination at 600 °C, the nanobelt structure remains intact. These metal oxide nanobelt (MNB) aerogels exhibit exceptional compressibility while retaining their mesoporous structure. As a demonstration, the resulting Al‐MNB aerogel can withstand compression up to 80% strain without fracturing while preserving its porous nanobelt structure and a high specific surface area of 228 m2 g−1 and a pore volume of 0.7 cm3 g−1 after heat treatment at 1300 °C. This work introduces an innovative strategy for creating a distinctive polymer‐like nanobelt microstructure, paving the way for novel applications of metal oxide aerogels with unique structures and enhanced performance. [ABSTRACT FROM AUTHOR]

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Copyright of Automatisierungstechnik is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A three-dimensional model of cephalosporin powder particles was constructed, and the interaction between the particles and the surface of the transport tool was simulated. In this paper, the microstructure of the tool surface was prepared by femtosecond laser technology and the effect of different tilt angles on the particle transport characteristics was investigated. The experiments show that the interaction force between the particles and the surface of the transport tool increases with increasing particle size, and the rate of change is 0.00854 μN/μm. The resistance required for particle shedding decreases and then increases as the angle of inclination of the machine increases. At a tilt angle of 30°, the interaction force between the particles and the machine is minimal. At less than 30°, the rate of change of resistance reduction is − 0.06021 μN/°. Above 30°, the rate of change of resistance increase is 0.0414 μN/°. The shedding rate of powder particles was higher on the transversely and longitudinally etched tool surfaces than on the unetched surfaces. This work demonstrates that femtosecond laser microstructures on metal tool surfaces can effectively prevent powder deposition on the tool surface. It provides an experimental basis for improving the metrology accuracy of ultrafine powder materials. [ABSTRACT FROM AUTHOR]

Liquid metal (LM) elastomer composites offer promising potential in soft robotics, wearable electronics, and human‐machine interfaces. Direct ink write (DIW) 3D printing offers a versatile manufacturing technique capable of precise control over LM microstructures, yet challenges such as interfilament void formation in multilayer structures impact material performance. Here, a DIW strategy is introduced to control both LM microstructure and material architecture. Investigating three key process parameters–nozzle height, extrusion rate, and nondimensionalized nozzle velocity–it is found that nozzle height and velocity predominantly influence filament geometry. The nozzle height primarily dictates the aspect ratio of the filament and the formation of voids. A threshold print height based on filament geometry is identified; below the height, significant surface roughness occurs, and above the ink fractures, which facilitates the creation of porous structures with tunable stiffness and programmable LM microstructure. These porous architectures exhibit reduced density and enhanced thermal conductivity compared to cast samples. When used as a dielectric in a soft capacitive sensor, they display high sensitivity (gauge factor = 9.0), as permittivity increases with compressive strain. These results demonstrate the capability to simultaneously manipulate LM microstructure and geometric architecture in LM elastomer composites through precise control of print parameters, while maintaining geometric fidelity in the printed design. [ABSTRACT FROM AUTHOR]

The main motivation for this study was to improve implant materials. The influence of silver and gold on the structure and mechanical properties of Mg–Nd–Zr alloy was studied. In the work, quantitative and qualitative evaluation of the structural components of magnesium alloy with noble metal additives was performed. The research methods used were investigation of the mechanical properties and observation of micro– and macrostructures. The results showed that modification of magnesium alloy with Ag and Au contributes to the formation of spherical intermetallics of smaller size groups, which become additional centers of crystallization and grind the cast structure. The best composition from additional alloying with silver and gold was determined. Their positive effect on the strength and ductility properties of the metal was established. Preclinical and clinical testing was performed and the prospects for noble metal modification of bioabsorbable magnesium alloy for implant production usage were shown. [ABSTRACT FROM AUTHOR]

TiZrHfAgV0.2 (Ti23.8Zr23.8Hf23.8Ag23.8V4.8, at%) high entropy alloys (HEAs) with a dual bcc structure were developed. Fine lamella structure was observed in the arc-melted ingots and melt-spun ribbons. The TiZrHfAgV0.2 HEAs with a dual bcc phase structure were designed by exploiting the concept of immiscibility of the constituent elements. The immiscibility of the constituent elements in the multi-component alloys was discussed using the mixing enthalpy (ΔHi-j) matrix of the i-j elements, binary phase diagrams with liquid miscibility gap, and the thermodynamic calculations. [ABSTRACT FROM AUTHOR]

With advancements in the exploration and development of deep and ultra-deep oil and gas resources, the number of ultra-deep wells continues to rise globally. This trend places higher demands on testing technology. The combined perforating and testing technique, an established method for deep and ultra-deep wells, faces challenges. Frequent test operation failures due to perforation detonation failure increase down-hole complexity, restricting the timeliness of testing operations. Current methods use mechanical calibration software to calculate the minimum safety factor of the tubing string for safety assessments. However, without a thorough understanding of perforation detonation failure theory, existing mechanical analysis software remains unreliable for assessing well safety during operations. Simply using the safety factor method lacks reliability and cannot explain the causes of perforation detonation failure. This paper examines an ultra-deep well, referred to as TW1, to analyze perforation detonation failure mechanisms. Through metal microstructure examinations, chemical composition analysis, electron microscope scanning, and numerical simulation, the study yields the following insights: (1) The packer mandrel of Well TW1 fractured due to overstress from the detonation waves. (2) Detonation wave propagation patterns along the tubing string during perforation become apparent. (3) Simulation methods reconstruct the perforation detonation process, calculating effective stress at different tubing string positions over time. (4) It introduces an innovative approach for assessing perforation detonation failure mechanisms through a combination of laboratory testing and simulation modeling. [ABSTRACT FROM AUTHOR]

The current study investigates the development of a replica molding process for hypervariable microstructures. Initially, the mold deformation theory for these hypervariable microstructures was derived. Based on this theory, a metal material with magnetic properties was selected as the structural material to create a negative Poisson's ratio (NPR) geometric structure. The experimental results, obtained by fabricating the NPR geometric mold layer with a metal material with adjustable magnetic properties and controlling microstructure deformation indirectly, validate the deformation theory and its predictions. These results demonstrate that the developed molding process, integrated with the magnetic NPR regulation system, exhibits excellent stability and replication capability. In this study, at the zero height (z = 0) position on the interface between the NPR geometric structure layer and the Polydimethylsiloxane (PDMS), the variation becomes more pronounced with increasing distance from the center of the microstructure. Furthermore, the tendency of the function curve varies accordingly. The primary cause is the lack of constraints on the free ends of both sides and the excessive constraints on the intermediate parts. Under the conditions in this study, the maximum ratio of its influence on the radial diameter thickness was 2.1%. This innovative process facilitates the rapid imprinting of microstructural components and offers the advantage of efficient molding. [ABSTRACT FROM AUTHOR]

Doping refractory metal silicates into the matrix of C/SiC composites is an effective means to improve their oxidation resistance. Previous studies have demonstrated that doping HfSiO 4 matrix availably enhanced the oxidation resistance of C/SiC composites, but the high raw material cost of HfSiO 4 limits its widespread application. This paper attempts to introduce ZrSiO 4 matrix, which has lower raw material cost and similar properties to HfSiO 4 , into C/SiC matrix through the same process. To clarify whether the microstructure of the refractory metal silicate doped matrix significantly impacts the oxidation behavior of C/SiC composites, the preparation temperature of ZrSiO 4 was increased to 1100 °C. The densification effect, oxidation behavior, and related mechanisms of C/SiC composites doped with ZrSiO 4 matrix were investigated and compared in detail with the previously studied C/SiC composites doped with HfSiO 4 matrix. Results show that the oxidation resistance behavior of C/SiC composites is relatively sensitive to the microstructure of the refractory metal silicate-doped matrix. At lower preparation temperatures of refractory metal silicates, the particle size of the composite matrix is significantly refined, which is conducive to improving the matrix densification degree of the composites and protecting more carbon fibers from erosion by the oxidizing environment, thus achieving a better oxidation resistance modification effect. [ABSTRACT FROM AUTHOR]

The study object was slag from the Balkhash copper smelter, obtained by re-melting anode mud containing nonferrous metals. The process flow for processing these slags includes sintering with Na2SO4, Na2CO3, and coal, followed by soda-alkaline leaching of the sinter and extraction of metals from the solution into marketable products. Since sintering is the main operation providing high selectivity, the composition of the products of this process was studied. The main transformations during sintering were determined, and the optimal parameters were identified. The structures of slags and sintered materials obtained during the experiments were studied by electron-probe microanalysis. Sintering was performed at 600–800 °C. The best results for sulphidization of slag components were obtained at 800 °C; a further increase in temperature leads to the smelting of sinter particles and slows down sulphidization. The optimal quantities of additives, based on the weight of the slag, are Na2SO4—45%, Na2CO3—15%, and reducing agent—41%, with a sintering time of 2 h. These conditions enable the sulphidization of non-ferrous metals in the slag to the entire depth of the polymetallic globules. The distinct concentration of harmful impurities (Ni, As, and Sb) was observed in the fine structure of the polymetallic globules. [ABSTRACT FROM AUTHOR]

The correlation of welding input heat and microstructure and its impacts on multi-pass mechanical properties in storage tanks alloy steel plate of thickness 6mm using multiple passes SMAW was investigated experimentally and using SOLIDWORKS and ANSYS thermal and Mechanical Simulator. The heat-affected zone (HAZ) dimension was calculated, and the deformation in each pass was also calculated. Optical microscopy was used to characterize the weld metal microstructure effects on joint mechanical properties, the effects of the three pass sequences in deformation, and the resulting alterations in weld metal microstructure. In addition, the impact of this alteration in corrosion resistance characteristics was investigated, and steel samples were simulated. The investigation results illustrated increasing the weldment deformation with increasing heat inputs in the three-pass sequence. The welding joint microstructure shows a big difference in M-A (martensite-austenite) phase formation between the first, second, and third pass microstructure. In addition, the microstructure examinations showed the formation of AF (acicular ferrite) in the third pass, with a higher percentage in the second and first pass. This research demonstrated scientific information about the expected deformation of each pass from the three welding joints, the alteration in microstructures, and the corrosion resistance of the weldment according to the alteration with welding heat input. [ABSTRACT FROM AUTHOR]

This study investigates the microstructure and first hydrogenation properties of Fe52Ti40Zr3V5 and Fe37Ti44Zr9V10 alloys, which are individual phases present in the as-cast TiFe + 12 wt.% ZrV2 alloy (parent alloy). The parent alloy exhibited fast first hydrogenation kinetics due to the interplay of these two phases. Our objective is to study the hydrogen storage behavior of these individual phases. The samples were synthesized by arc melting and characterized by X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The results show that when these alloys are melted separately, they do not exhibit the same phase composition as in the parent alloy, indicating a metastable state under our synthesis conditions, which significantly impacts their hydrogen storage behavior. Hydrogenation capacity was measured using a homemade Sieverts apparatus. Both alloys demonstrated excellent first hydrogenation kinetics, with an absorption capacity of 0.9 wt.% for the Fe52Ti40Zr3V5 alloy and 2.3 wt.% for Fe37Ti44Zr9V10 alloy. Our key finding is that the final crystal structure of multi-element alloys is highly dependent on the synthesis method. [ABSTRACT FROM AUTHOR]

Two advanced manufacturing processes, spark plasma sintering (SPS) and selective laser sintering (SLS), have been developed for synthesis of (Zr,Nb,Ta,Ti,W)C compositionally complex carbide (CCC) via reactive sintering of a powder mixture of constitute monocarbides. X‐ray diffraction analysis confirmed that the single‐phase CCC can be formed by both SPS and SLS. While a homogenous microstructure with uniform metal element distributions was developed during SPS, three‐layer microstructures with a thin TiC‐rich layer and two TaC‐rich layers along with a TiO2‐rich surface layer containing W nanoparticles were formed during SLS. In addition, cellular structures with W, Zr, and Ti element segregation and dislocations on cell boundaries were observed in the SLS‐CCC sample, indicating the effect of nonequilibrium conditions on microstructure formation during laser melting followed by rapid cooling and solidification process. Compared to the SPS‐CCC sample, the SLS‐CCC showed enhanced hardness and reduced thermal conductivity, which may be related to their unique cellular structures. [ABSTRACT FROM AUTHOR]

A terahertz metamaterial microfluidic sensing chip for ultrasensitive detection is proposed to investigate the response of substances to terahertz radiation in liquid environments and enhance the molecular fingerprinting of trace substances. The structure consists of a cover layer, a metal microstructure, a microfluidic channel, a metal reflective layer, and a buffer layer from top to bottom, respectively. The simulation results show that there are three obvious resonance absorption peaks in the range of 1.5–3.0 THz and the absorption intensities are all above 90%. Among them, the absorption intensity at M1 = 1.971 THz is 99.99%, which is close to the perfect absorption, and its refractive index sensitivity and Q-factor are 859 GHz/RIU and 23, respectively, showing excellent sensing characteristics. In addition, impedance matching and equivalent circuit theory are introduced in this paper to further analyze the physical mechanism of the sensor. Finally, we perform numerical simulations using refractive index data of normal and cancer cells, and the results show that the sensor can distinguish different types of cells well. The chip can reduce the sample pretreatment time as well as enhance the interaction between terahertz waves and matter, which can be used for early disease screening and food quality and safety detection in the future. [ABSTRACT FROM AUTHOR]

The object of this research is the horizontal centrifugal casting process of the Al6061 alloy. Usually, cast products experience some casting defects, so the horizontal centrifugal casting process is applied to reduce the possibility of casting defects arising. In some casting processes, especially in the production of cylindrical specimens, casting defects such as porosity are encountered. Therefore, horizontal centrifugal casting was applied to overcome this problem. The test results show that the average hardness value for aluminum 6061 specimens resulting from centrifugal casting products with water cooling was 73.3 HRE, while the average hardness value for aluminum 6061 specimens resulting from centrifugal casting products without water cooling was 86.4 HRE. The microstructure results show that the grain size of centrifugal casting products with water cooling was 82.5 µm, whereas without water cooling it was 75 µm. Higher hardness values were obtained in specimens without mold cooling, this is because the conductivity in molds without cooling was higher compared to molds that experienced water cooling. The higher the heat conductivity of the mold, the faster the cooling process of the cast product. The casting process using the horizontal centrifugal method can be carried out to produce cylindrical spare parts. [ABSTRACT FROM AUTHOR]

This study explores the impact of different pre-temper conditions of the base metal (BM) on the microstructure and strength-ductility performance of AA7075 welded joints, aiming to identify effective processing approaches for aluminum alloy forming. The findings reveal that in comparison to the average grain size (AGS) in the weld nugget zone (NZ) of the AA7075-T6 joint (approximately 2.85 µm), the grain refinement is more pronounced in the NZ of the AA7075-O joint (approximately 2.09 µm). Concerning mechanical performance, the AA7075-T6 joint experiences softening in the welding region, demonstrating significantly lower tensile properties than the BM, with an ultimate tensile strength of 416 MPa and an elongation of 4.4 %. Conversely, the AA7075-O joint undergoes hardening in the welding region, displaying higher tensile strength than the BM, with an elongation of 8.7 %. Three-point bending destructive experiments results indicate that the AA7075-O joint can withstand larger bending angles, displaying more thorough plastic deformation and superior forming performance. [ABSTRACT FROM AUTHOR]

To achieve the necessary mechanical properties and high corrosion resistance, heat treatment is based on a significant alteration in the microstructure of metals and alloys. The metal is heated above a critical temperature during heat treatment processes. Several methods, such as quenching and cooling in various media, followed by tempering and other heat treatment operations, can be used to achieve this. Steel can be made more malleable by annealing, which also increases ductility and improves corrosion resistance. In this study, thirty medium carbon steel specimens were used, which were split into different groups, various heat treatments were applied. First quenching, first tempering, second quenching, and second tempering were among the heat treatment procedures used, and cooling media made of distilled water were used at various temperatures. After that, the corrosion rate in these specimens was looked at, and the results were compared to the corrosion rate in the base specimen. The results show that repeated heat treatment of the metal generally lowers the rate of corrosion in the metal, particularly when distilled water is used for the cooling process after the two tempering stages at a temperature of almost absolute zero. The findings show that the second sample had the lowest corrosion rate of all the samples. When compared to the corrosion rate in the basic sample, the corrosion rate in this sample decreased by about 92.9%. [ABSTRACT FROM AUTHOR]

Corrosion inhibitors are one of the best practices to prevent the far-reaching negative impacts of corrosion on ferrous alloys. A thorough understanding of their corrosion-inhibiting effects is essential for a sustainable economy and environment. Anionic surfactants are known to act efficiently as corrosion inhibitors. Here, we present that in-situ atomic force microscopy (AFM) measurements can provide deep insights into the adsorption and inhibition mechanism of surfactants on stainless steel surfaces during local corrosion. These include the configuration of surfactant molecules on the surface and how the microstructure of the stainless steel surface influences the inhibition process. Three different anionic surfactants, namely palm kernel oil (PKO), linear alkylbenzene sulfonate (LAS), and fatty alcohol ether sulfate (FAES), were investigated on a titanium-stabilized ferritic stainless steel (1.4510) in NaCl solution. For PKO, the results show random adsorption of bi- and multilayer whereas LAS and FAES adsorb only as local corrosion occurs. Thereby, LAS accumulates only locally and especially at the titanium precipitates of the 1.4510 and FAES forms a densely packed monolayer on the surface. This leads to better corrosion inhibiting properties for LAS and FAES compared to PKO. [ABSTRACT FROM AUTHOR]

Electrochemical discharge machining (ECDM) micro-milling exhibits enormous machining potential in manufacturing metal microstructures. In this paper, a novel sinking ECDM micro-milling using glycol-based electrolyte is proposed for the high-quality fabrication of metal micro-channel structures. Firstly, a novel combined process is developed for the simple and efficient preparation of micro-electrode. With the proposed method, a micro-electrode with 91.1 μm in diameter and 21.2:1 in aspect ratio is successfully machined in 47.2 minutes. Secondly, experimental research on ECDM micro-milling machining of micro-channels in glycol-based electrolyte is carried out using the fabricated micro-electrode. Experimental results show that the machined voltage significantly affects the machining quality of micro-channels. Wear analysis reveals that the bottom geometry of the micro-electrode exhibits equal wear along the axis direction with processing times increasing, and a constant length compensation strategy (1.52 μm/mm) is adopted. Finally, an S-shaped micro-channel without recast layers (Ra 0.093 μm) was successfully fabricated. [ABSTRACT FROM AUTHOR]

This paper presents the synthesis and characterization of Al-0.35Cu-0.18Sc-0.06Zr alloys, possessing remarkable electrical and mechanical properties. Specifically, the electrical conductivity and tensile strength of this alloy are reported to reach 60.4%IACS and 169.46 MPa, respectively. The electrical conductivity combined with Wiedemann–Franz law was calculated for Al-0.35Cu-0.18Sc-0.06Zr alloys thermal conductivity as showing excellent thermal conductivity. Microscopic analysis shows that a large number of fine "bean-petal" shaped Al3(Sc, Zr) particles, i.e., the second phase, were diffusely distributed in the alloy. These particles are highly cohered with the matrix, resulting in small and shallow toughness dimples at the tensile fracture. Due to the low diffusion coefficient of Zr element, the growth rate of precipitated second phase particles can be effectively reduced, which leads to forming Al3(Sc, Zr) phase with Zr-rich shell and improving the intrinsic coarsening property of Al3Sc phase. The Al3(Sc, Zr) second phase exhibits a large surrounding strain of approximately 2.5%, resulting in a significant elastic strain field that inhibits dislocation movement, thereby increasing alloy strength. Furthermore, the heat resistance test results show that the alloy can operate steadily at 503 K for up to 350, 400 h. [ABSTRACT FROM AUTHOR]

The inoculation of nano-sized particles of refractory Al2O3, TiO2, MgO, ZrO2 oxides into the welding bath was studied. The inoculation of oxides with a low-level mismatch to the δ-Fe lattice and increased wetting with liquid iron (MgO, ZrO2) contributes to the growth of dendrites, which are formed during melt crystallization. Metal modification with MgO, ZrO2 oxides decreases the hardness of polygonal ferrite and increases the content of lower bainite in the microstructure of joints, brittle fracture resistance of the joint metal. Metal modification with Al2O3, TiO2 oxides contributes to an increase in the hardness of polygonal ferrite, the content of upper bainite in the joint microstructure, and the strength of welded joints of low-alloy steels. [ABSTRACT FROM AUTHOR]

Rational morphology control of inorganic microarchitectures is important in diverse fields, requiring precise regulation of nucleation and growth processes. While wet chemical methods have achieved success regarding the shape‐controlled synthesis of micro/nanostructures, accurately controlling the growth behavior in real time remains challenging. Comparatively, the electrodeposition technique can immediately control the growth behavior by tuning the overpotential, whereas it is rarely used to design complex microarchitectures. Here, the electrochemical design of complex Cu2O microarchitectures step‐by‐step by precisely controlling the growth behavior is demonstrated. The growth modes can be switched between the thermodynamic and kinetic modes by varying the overpotential. Cl− ions preferably adhered to {100} facets to modulate growth rates of these facets is proved. The discovered growth modes to prepare Cu2O microarchitectures composed of multiple building units inaccessible with existing methods are employed. Polyvinyl alcohol (PVA) additives can guarantee all pre‐electrodeposits simultaneously evolve into uniform microarchitectures, instead of forming undesired microstructures on bare electrode surfaces in following electrodeposition processes is discovered. The designed Cu2O microarchitectures can be converted into noble metal microstructures with shapes unchanged, which can be used as surface‐enhanced Raman scattering substrates. An electrochemical avenue toward rational design of complex inorganic microarchitectures is opened up. [ABSTRACT FROM AUTHOR]

Samples of alloy 601, 602 CA and 602 MCA with different thickness and microstructure, all 600 grit laboratory ground, are compared. All samples are exposed to up to 5693 h at 600°C in a metal dusting producing atmosphere with a total pressure of 20 bar. A smaller sample thickness leads to an increased pit density for alloy 601 and an increased pit density, a longer incubation time and an increased pit depth growth rate for alloy 602 CA. This is attributed to lower stresses in the scale of the thinner samples. Grain size effects of the substrate are probably concealed by the deformed and recrystallized subsurface due to the 600 grit finish of the samples. If carbides are unavoidable in an alloy, they should be small, as they can serve as chromium suppliers during scale formation better than larger ones. They increase incubation time and pit depth growth rate. [ABSTRACT FROM AUTHOR]

The structure of the base metal and weld metal after electron-beam welding (EBW) of the intermetallic titanium alloy Ti−28Al−7Nb−2Mo−2Cr (wt.%) obtained by the electron-beam melting method is studied. The macrostructure of the Ti−28Al−7Nb−2Mo−2Cr alloy ingot is characterized by grains close to equiaxed with a grain size of 8–9 points. As shown, the microstructure of the cast metal of the Ti−28Al−7Nb−2Mo−2Cr alloy consists of a matrix bright γ-phase alternating with sections of a two-phase (γ + α2) lamellar structure up to 50 µm in size, with a lamellae thickness of about 1 µm, and of the ordered β-phase, which forms a mesh pattern against the background of the matrix. As established, the intragranular structure of the metal of the welded joint after EBW with local heat treatment (LHT) differs from the structure of the base metal and consists of small (up to 20 µm) areas with a (γ + α2) lamellar structure against the background of a light matrix γ-phase with a network of elongated particles of 30−80 µm long and 1−3 µm thick. [ABSTRACT FROM AUTHOR]

The derivatives of metal–organic frameworks have been proven to be ideal candidates for microwave absorption due to their ability to form diverse microstructures of metals/heteroatom doped-carbon composites. In this study, we synthesized three types of zinc oxide (ZnO)@ZIF-8 with varying ZIF-8 shell thicknesses using ZnO colloidal spheres as sacrificial templates. Subsequently, we investigated the microwave absorption properties of a series of non-magnetic ZnO/N-doped carbon nanospheres pyrolyzed by ZnO@ZIF-8 at different temperatures. Remarkably, the non-magnetic samples (30 wt% filler loading) with a hollow structure pyrolyzed at 800 °C exhibited a broad effective absorption band exceeding 6 GHz. The excellent microwave absorbing performance of the samples pyrolyzed at 800 °C can be attributed to the reduction of the ZnO core to Zn0, anchoring it in the graphitized N-carbon layer, and the formation of an inner hollow cavity that enhances impedance matching. Therefore, this research not only provides an array of excellent dielectric-type microwave absorbing materials but also presents a novel strategy for developing lightweight and high-performance non-magnetic carbon-based microwave absorbing materials. [ABSTRACT FROM AUTHOR]

To satisfy the needs of precision machining, ultrafine tungsten carbide (WC)-based cemented carbide with fine grain size and excellent mechanical properties was prepared. Ultrafine cemented carbide was prepared by spark plasma sintering (SPS) using WC, Co as raw materials and metal elements V, and Cr as additives, and the effects of metal elements on the microstructure and mechanical properties of cemented carbide were investigated. The results show that the specimen (91.6WC-1.2V-1.2Cr-6Co) prepared at 1350 °C, 6 min, 25 MPa has the best mechanical properties (HV 2322.9, KIC 8.7 MPa·m1/2) and homogeneous microstructure. The metal elements could react with WC to form a (W, V, Cr) Cx segregation layer, which effectively inhibits the growth of WC grains (300 nm). The combination of SPS and metal element additives provides a new approach for the preparation of ultrafine cemented carbides with excellent properties. [ABSTRACT FROM AUTHOR]

Brazing of hot work steel with nickel‐based filler metals is a widely used process for manufacturing casting tools. However, the formation of brittle phases in the joint impairs its mechanical properties. Reducing these intermetallic phases is an important aspect. Thermodynamic equilibrium calculations are used to estimate the change in melting range and apearance of intermetallic phases by adding different amounts of molybdenum to Ni 620. The filler metals are then produced and their solidus and liquidus temperatures are investigated using differential scanning calorimetry. Specimens of X37CrMoV5‐1 are then brazed in a vacuum furnace and their microstructure is analysed by scanning electron microscopy/electron dispersive spectroscopy and their hardness properties by nanoindentation. The addition of molybdenum to the Ni 620 filler metal leads to the formation of chromium molybdenum boride rich phases and reduced hardness values in brazed joints. Manipulation of Ni 620 by molybdenum helps to improve relevant properties in brazing hot work steel. [ABSTRACT FROM AUTHOR]

When fabricating a metal powder filter with a double-layered pore structure, which includes a microporous layer, by coating flake-shaped powder using the Wet Powder Spray (WPS) process, it is crucial to ensure that the coating is applied parallel to the surface of the metal powder filter. Failure to do so can result in a non-uniform pore structure, leading to a rapid decline in particle filtration efficiency. Therefore, it is necessary to improve the alignment of the coated flake-shaped powder on the filter surface. In this study, a metal powder filter with a double-layered pore structure was fabricated by applying a flake-shaped metal powder coating to a tube-shaped SUS316L powder filter using the WPS process. In order to improve the flake-shaped powder orientation of coating layer, the impact of the rolling process was investigated. The characteristics of the pores were analyzed based on the powder size and the rolling time. The microstructure of the fabricated metal powder filter was observed using an optical microscope, surface roughness, variations in thickness, and air permeability were analysed. [ABSTRACT FROM AUTHOR]

It has been a common method to improve the mechanical properties of metals by manipulating their microstructures via static recrystallization, i.e., through heat treatment. Therefore, the knowledge of recrystallization and grain growth is critical to the success of the technique. In the present work, by using in-situ high temperature EBSD, the mechanisms that control recrystallization and grain growth of an extruded pure Mg were studied. The experimental results revealed that the grains of priority for dynamic recrystallization exhibit fading competitiveness under static recrystallization. It is also found that grain boundary movement or grain growth is likely to show an inverse energy gradient effect, i.e., low energy grains tend to swallow or grow into high energy grains, and grain boundaries of close to 30° exhibit superior growth advantage to others. Another finding is that {10–12} tensile twin boundaries are sites of hardly observed for recrystallization, and are finally swallowed by adjacent recrystallized grains. The above findings may give comprehensive insights of static recrystallization and grain growth of Mg, and may guide the design of advanced materials processing in microstructural engineering. [ABSTRACT FROM AUTHOR]

This document is a summary of two journal articles in the field of materials science. The first article discusses the importance of microstructure design in achieving desired material properties, with a focus on metals and alloys in aeronautical and aerospace applications. It includes a list of related articles covering topics such as welding and phase transformation. The second article is a compilation of various research studies in materials science, covering topics such as the effects of boron additions on alloy microstructure and the properties of porous alloys. Both articles provide valuable insights into the behavior and properties of different materials. The document acknowledges the contributions of the authors and reviewers and expresses gratitude to the publisher, MDPI. [Extracted from the article]

The 2A50 aluminum alloy micro inner gear rings were fabricated using a rheological extrusion process. Metal flowing and microstructure characteristics of the micro inner gear rings in rheological extrusion were investigated by finite element simulation and experiments, respectively. The microstructures of the tooth, bottom land, and non-dentiform region were considered as representative sections of the inner gear ring. Results reveal that during the rheological extrusion process, the metal exhibited a continuous flow from the periphery toward the center of the billet along the radial direction, meticulously filling the tooth spaces of the mandrel. Concurrently, a gradual decline in flow velocity was observed. The grains in the teeth and bottom lands were fine and elongated along the flowing lines, whereas those in the non-dentiform region were similar to the semi-solid slurry with nearly equiaxed grains. The microstructure of the micro inner gear rings predominantly consisted of recrystallized grains and substructures. In non-dentiform regions, the proportion of recrystallized grains was remarkably higher than that of the substructure. The average grain size of the microstructure of the inner gear ring ranged between 14.04 and 20.05 μm. The grain size in the tooth was sensitive to the extruded temperature and showed an increment of approximately 36.3% when the temperature increased from 575 °C to 590 °C. This phenomenon suggests that low temperature in the semi-solid range was advantageous for the microstructure and mechanical performance of the inner gear ring. No pronounced texture was detected in the micro inner gear rings, and the peak intensity (4.81) in the pole figures was found in the bottom land at the extruded temperature of 590 °C, suggesting a relatively weak {112} < 126 > texture. This process recommends a propitious technique for the fabrication of components with microfeatures. [ABSTRACT FROM AUTHOR]

Ni anisotropic microgroove structures were prepared by lithographic processes and electroforming to investigate the effect of microstructures on friction forces. For Ni microgroove structures, the friction forces varied significantly depending on the indenter sliding direction to the anisotropic microstructures. The friction forces of parallel sliding directions on microgroove structures were unstable and considerably larger than those of the perpendicular directions owing to the difference in the structure continuousness. These results suggest that anisotropic microstructures affect friction forces and can deploy fail-safe functions when a large load is accidentally applied. [ABSTRACT FROM AUTHOR]

Cathodic protection is widely used for metal corrosion protection. To improve their performance, it is necessary and urgent to study the influence of metal oxides on the microstructure and performance of aluminum alloy sacrificial anodes. Taking an Al-Ga-In sacrificial anode as the research object, the dissolution morphology and current efficiency characteristics were studied by means of electrochemical testing and microstructural observation, and the influence of varying Pb and Bi contents on the performance of an aluminum alloy sacrificial anode was investigated. The test results reveal that: (1) The Al-Ga-In sacrificial anode with 4% Pb and 1% Bi contents exhibits the best sacrificial anode performance. (2) The inclusion of an appropriate Bi element content shifts the open-circuit potential in a negative direction and promotes activation dissolution. Conversely, excessive Bi content leads to uneven dissolution, resulting in the shedding of anode grains and greatly reducing the current efficiency. (3) During the activation dissolution of the aluminum alloy, the second phase preferentially dissolves, and the activation point destroys the oxide film, resulting in the dissolution of the exposed aluminum matrix. Consequently, the concentration of dissolved metal ions is reduced and deposited back on the surface of the anode sample, promoting the continuous dissolution of the anode. [ABSTRACT FROM AUTHOR]

To address the issue of liquid metal embrittlement (LME) susceptibility in galvanized 22MnB5 steel during the hot stamping process, the material's performance is affected. This study proposes a method combining precooling and tube hydroforging to produce galvanized tubular hot stamping parts. The primary workflow comprises four distinct stages: the heating phase, thermal retention phase, precooling phase, and the tube hydroforging phase. Notably, the precooling stage employs two distinct approaches: air precooling and boiling water precooling. The composition and morphology of the zinc coating and the microstructure and mechanical properties of the 22MnB5 steel are investigated using two precooling methods at different hydroforging temperatures. The results show that when the initial hydroforging temperature is below 800 °C, the precooling combined with the tube hydroforging process eliminates LME. With increasing precooling time, the oxidation reaction forms ZnO and Fe2O3 on the coating. By comparing the composition, morphology, and mechanical properties of the coatings at hydroforging temperatures of 800 °C and 500 °C, it is concluded that the boiling water precooling aligns more effectively with the requirements of industrial production, with the optimal forming temperature being within the range of 750–800 °C. [ABSTRACT FROM AUTHOR]

This paper presents a WR‐2.2 band (330–500 GHz) waveguide with E‐plane bends and a waveguide bandpass filter. A micro‐metal additive manufacturing technology employs copper to process these devices. This technology includes several micromachining processes, which can produce integrated, miniaturized, and complex three‐dimensional metal microstructures when meeting the process constraints. To successfully apply this technology to the fabrication of terahertz waveguide devices, many design details are considered. First, the E‐plane bent transition structures in the waveguide overcome size limitations imposed by the manufacturing process, allowing for accurate measurement using standard waveguide interfaces. Second, the rectangular resonators compose the fifth‐order waveguide bandpass filter spanning 20 GHz with a center frequency of 380 GHz. Given that the excess photoresist needs to be removed, some release holes are designed in the proper positions of the filter. Third, to increase the uniformity of the device layout and improve the machining quality in the electroforming process, a lot of rectangular holes are arranged around the device. By adopting a meticulous and novel design method in accordance with the process advantages and limitations, the fabrication accuracy of the device size is greatly increased. The integrated filter with exceptional performance is obtained. The measured average insertion loss within the passband is better than 1.2 dB, and the return loss exceeds 15 dB. Additionally, the filter demonstrates a center frequency offset of approximately 0.5%. Good consistency between simulation and measurement shows the validity of design and fabrication. [ABSTRACT FROM AUTHOR]

Locally confined electrodeposition of precursors in liquid is one of the most effective approaches for additive manufacturing of metal microstructures. However, reported data were overwhelmingly obtained at the micrometer scale, whereas sub-microscale and nanoscale microstructures are of interest in electromagnetic or optical fields. In this paper, we propose a cold-constrained local electrodeposition (CCLE) technique to address the issue that locally confined electrodeposition of precursors in liquid is challenging in the fabrication of sub-microscale three-dimensional microstructures. Microstructure printing is conducted via locally confined electrodeposition by a pipette with a sub-microscale opening to deliver electrodeposition electrolyte in a supporting electrolyte. The electrolytes are cooled to 5 °C, which constrains the large-scale diffusion of the electrodeposition electrolyte and significantly reduces the electrodeposition area. It is found that the proposed CCLE technique can print sub-microscale (minimum size is low to 290 nm) structures, which have highly uniform deposits, smooth surfaces and high strength. [ABSTRACT FROM AUTHOR]

Energetic structural materials (ESMs) are a new type of structural materials with bearing and damage characteristics. In this work the microstructure, mechanical properties and energy release characteristics of multi-element TieZreTa alloys with good casting performance were studied. The microstructure of the TixZrTa alloys gradually change from BCC þ HCP to single BCC structure with the increase of Ti. While the Ti2ZryTa alloys was still uniform and single BCC structure with the increase of Zr. The evolution of microstructure and composition then greatly affect the mechanical properties and energy-release characteristics of TieZreTa alloys. The synergistic effect of dual phase structure increases the fracture strain of TixZrTa (x = 0.2, 0.5) with the Ti content decreases, while the fracture strain of TixZrTa (x = 2.0, 3.0, 4.0) gradually increase with the Ti content increases caused by the annihilation of the obstacles for dislocation movement. And as Zr content increases, the fracture strain of Ti2ZryTa alloys decrease, then the oxidation reaction rate and fragmentation degree gradually increase. The higher oxidation rate and the lager exposed oxidation area jointly leads the higher releasing energy efficiency of TixZrTa alloys with low Ti content and Ti2ZryTa alloys with high Zr content. [ABSTRACT FROM AUTHOR]

The article shows the results of the analysis of changes in the microstructure and volumetric particles of phase components of HAZ metal in modelling with the use of the Gleble-3800 device of welding thermal cycles, which are inherent in wet underwater welding and welding in air. The value of cooling rate of different areas of weld metal in wet underwater welding and welding in air was determined. It is shown that as a result of cooling impact of water environment, the cooling rate in wet underwater welding is almost by an order higher than that of welding in air (w13/8 = 8.21 ºC/c -- air, in the middle of the weld, and in wet underwater welding it is accordingly W13/8 = 81.70 ºC/c in the middle of the weld, w13/8 = 165.85 ºC/c at the beginning of the weld and w13/8 = 320,51 ºC/c in the weld crater). The change in volumetric particles of phase components of ferrite, austenite and excess phases (chromium Cr2N nitride) was determined in the microstructure of HAZ metal depending on the cooling rate. Phase transformations almost completely occur in the high-temperature heat-affected-zone (HHAZ) in the temperature range T = 1300...800 ºC. Contribution of low-temperature heat-affected-zone (LHAZ), temperature range T = 800...500 °C on the change in phase components is negligible. The amount of ferritic and austenitic components and especially the morphology of austenite in the microstructure of HHAZ depend on the cooling rate, as well as the amount of precipitation of excess phases (probably chromium Cr2N nitrides). Ref. 13, Tabl. 5, Fig. 8. Keywords: duplex steels, wet underwater welding, input energy, cooling rate, phase composition, austenite, ferrite, microstructure in HAZ, HAZ modelling, thermal welding cycle, Gleeble [ABSTRACT FROM AUTHOR]

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Titanium alloys are acclaimed for their remarkable biocompatibility, high specific strength, excellent corrosion resistance, and stable performance in high and low temperatures. These characteristics render them invaluable in a multitude of sectors, including biomedicine, shipbuilding, aerospace, and daily life. According to the different phases, the alloys can be broadly categorized into α-titanium and β-titanium, and these alloys demonstrate unique properties shaped by their respective phases. The hexagonal close-packed structure of α-titanium alloys is notably associated with superior high-temperature creep resistance but limited plasticity. Conversely, the body-centered cubic structure of β-titanium alloys contributes to enhanced slip and greater plasticity. To optimize these alloys for specific industrial applications, alloy strengthening is often necessary to meet diverse environmental and operational demands. The impact of various processing techniques on the microstructure and metal characteristics of titanium alloys is reviewed and discussed in this research. This article systematically analyzes the effects of machining, shot peening, and surface heat treatment methods, including surface quenching, carburizing, and nitriding, on the structure and characteristics of titanium alloys. This research is arranged and categorized into three categories based on the methods of processing and treatment: general heat treatment, thermochemical treatment, and machining. The results of a large number of studies show that surface treatment can significantly improve the hardness and friction mechanical properties of titanium alloys. At present, a single treatment method is often insufficient. Therefore, composite treatment methods combining multiple treatment techniques are expected to be more widely used in the future. The authors provide an overview of titanium alloy modification methods in recent years with the aim of assisting and promoting further research in the very important and promising direction of multi-technology composite treatment. [ABSTRACT FROM AUTHOR]

In manufacturing, thermomechanical processes such as static annealing and hot working are commonly used to tailor the microstructure of metals to achieve favourable macroscopic material properties that meet specific application requirements. To improve sequential manufacturing processes and to accurately predict the microstructural changes of the material along the process chain, physically motivated constitutive models are required that simultaneously account for the effects of recovery and recrystallisation, as well as grain size dependencies. To this end, Cho et al. [Int. J. Plasticity 112, 123–157 (2019)] proposed a macroscopic hypo‐elasticity based large strain thermoplasticity model that aims at the unification of the effects of static and dynamic recovery and recrystallisation, as well as grain growth and refinement. In the present contribution, the hypo‐elasticity based large strain recrystallisation formulation proposed by Cho et al. is transferred to a hyper‐elasticity based large strain thermoplasticity framework to overcome the limitations typically accompanied with hypo‐elasticity based formulations. For this purpose, an isotropic temperature dependent hyper‐elastic Hencky type formulation defined in logarithmic strains is combined with a temperature dependent von Mises yield criterion. The recrystallisation modelling approach by Cho et al. is adopted, assuming a non‐associated temperature dependent proportional hardening rate in the form of an Armstrong‐Frederick type hardening minus recovery format, wherein the proportional hardening related internal variable is interpreted as a measure of dislocation density. It is shown that the hyper‐elasticity based format results in a thermodynamical consistency condition that effectively constrains the physically motivated evolutions of recrystallised volume fraction and average grain size. To investigate the capability of the model to predict the material response of unified recrystallisation thermodynamically consistently, representative thermomechanical sequential loading conditions including static annealing and hot working are studied. [ABSTRACT FROM AUTHOR]

In this work, the approach to improve the mechanical properties of a biodegradable Mg-Nd-Zr alloy through modification with noble metals (Ag and Au) was proposed. The separate and combined influence of silver and gold on the macro- and microstructure of the alloy was studied. A qualitative and quantitative assessment of the structural components of the alloy was carried out. It was shown that when modifying the melt, noble metals form the complex intermetallic phases which served as additional crystallization centers. It has been established that adding 0.05 to 0.1 wt.% of noble metals to Mg-based alloy increase the volume fraction of intermetallic compounds by ~1.5 times, shifting them towards smaller size groups with the simultaneous formation of spherical intermetallic compounds. The latter are located in the center of the grain proving them to be the additional nucleation sites. It was shown that complex modification (0.1% Ag + 0.1% Au) of a Mg-based alloy refined its structural components by ~1.5 times, increasing the strength by ~20%, and ductility by ~2 times due to the formation of the intermetallic compounds. The proposed technology for modifying cast biodegradable Mg-based alloys is feasible to be used for the manufacture of implants for osteosynthesis. [ABSTRACT FROM AUTHOR]

In the present research, the welding of HSLA-100 steel was performed using ER100S-G, ER120S-G, and ER2209 filler rods via the gas tungsten arc welding process. The microstructure, mechanical properties, erosion behavior, and corrosion resistance of all three weld metals were evaluated and compared. Microstructural investigations showed that the ER100S-G weld metal microstructure comprised grain boundary, widmanstatten and acicular ferrites with a continuous network of M/A constituents (mainly the blocky type) at grain boundaries, and that the microstructure of ER120S-G weld metal consisted of acicular, polygonal, and quasi-polygonal ferrites with finely dispersed M/A constituents (mainly the stringer type) at grain boundaries and within the grains. The microstructure of the ER2209 weld metal was also comprised of two phases: ferrite (47%) and austenite (53%). The mechanical tests demonstrated that the ER120S-G weld metal had the highest strength and hardness and that the ER2209 weld metal had the highest impact energy. Moreover, the erosion test results showed that the ER120S-G and ER100S-G weld metals had a better erosive behavior at the 90° impact angle and that the ER2209 and ER120S-G weld metals revealed better behaviors at 30° impact angle. In addition, it was found that all weld metals have lower erosion rates than the base metal. The corrosion test results also disclosed that the ER2209 weld metal had the highest uniform and pitting corrosion resistance. [ABSTRACT FROM AUTHOR]

It is known that the meso- and microstructures of metals determine the physical, mechanical and operational properties of their final products. Scientific and technological progress of recent decades has given impetus to the elaboration and use of models capable of describing the evolving structure of materials. The most promising are multilevel models that include internal variables and are based on physical theories of elastoplasticity (elastoviscoplasticity). This paper presents the structure and basic relationships of a three-level (macro-, meso-1 and meso-2 levels) elastoviscoplastic model. The developed model operates on such internal variables as dislocation densities on slip systems, barriers on split dislocations and sources of edge dislocations. The model describes the mechanisms of production, annihilation, formation of barriers and sources of dislocations. The law of hardening directly takes into account the densities of dislocations and barriers. The mechanism of inelastic deformation is the gliding of edge dislocations along slip systems. Special emphasis is placed on the influence of split dislocations (prone to forming hard Lomer–Cottrell and Hirth barriers) on the deformation of the material. The model is used to describe the behavior of an elastoviscoplastic polycrystalline aggregate with an FCC lattice. Geometric nonlinearity is taken into account by utilizing decomposition of the crystallite motion into quasi-rigid and deformation components. For this purpose, a rigid moving coordinate system for the crystal lattice is introduced. Examples of the application of the model for analyzing the simple and complex deformation mechanisms of materials with different stacking fault energies and, consequently, with different tendencies toward the decomposition of dislocations and barrier formation are given. [ABSTRACT FROM AUTHOR]

Thin film technology of lithium-ion solid electrolytes should be developed for the creation of all-solid-state power sources. Solid electrolytes of the Li7La3Zr2O12 (LLZ) family are one of the promising membranes for all-solid-state batteries. LLZ films were obtained by electrophoretic deposition on Ti, Ni and steel substrates. The influence of different metal substrates on microstructure, phase composition and conductivity of the LLZ films after their heat treatment was studied. It was shown that the annealing of dried LLZ films in an Ar atmosphere leads to the transition from tetragonal modification to a low-temperature cubic structure. It was established that an impurity phase (Li2CO3) was not observed for LLZ films deposited on Ti foil after heat treatment, in contrast to films deposited on Ni and steel substrates. The highest lithium-ion conductivity values were achieved for the LLZ films annealed at 300 °C, 1.1 × 10−8 S cm−1 (at 100 °C) and 1.0 × 10−6 S cm−1 (at 200 °C). [ABSTRACT FROM AUTHOR]

This study conducted a basic investigation to improve the solidification cracking susceptibility of carbon steel. BTR is one of the susceptibilities to solidification cracking, and it is said that solidification cracking susceptibility is reduced when BTR is smaller. BTR of three commercial filler metals was evaluated by using Trans-Varestraint test. EPMA and EDS analysis of the weld metal microstructure revealed two compounds. The white structure was composed of silicon, manganese, and sulphur, and the black structure was Ti-based compound. Theoretical analysis of BTR was conducted by applying a two-phase peritectic solidification model in FA mode and considering MnS crystallization during solidification segregation. The analysis results indicated that BTR of carbon steel is attributed to the difference in solidification completion temperatures, and carbon is the most deleterious element. Also, MX compound (Ti, C, N) crystallized in addition to MnS at the end of solidification. Theoretical analysis was conducted for Ti virtual addition materials because MX compound (Ti, C, N) crystallization by Ti addition may lead to BTR reduction by trapping C in the liquid phase. The results showed that Ti addition reduced BTR. The amount of C in the residual liquid phase was reduced by an increase in MX compound (Ti, C, N) crystallization due to Ti addition. Based on theoretical considerations, it can be concluded that Ti addition to carbon steel is effective in reducing BTR. [ABSTRACT FROM AUTHOR]