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In this paper, TiN-Ni nanostructured composite films with different Ni contents are prepared using the magnetron sputtering method. The composition, microstructure, and mechanical properties of composite films are analyzed using an X-ray energy spectrometer (EDS), a scanning electron microscope (SEM), X-ray diffraction technology (XRD), a transmission electron microscope (TEM), and nanoindentation. All the films grow in a columnar crystal structure. There are only TiN diffraction peaks in the XRD spectrum, and no diffraction peaks of Ni and its compounds are observed. The addition of the Ni element disrupts the integrity of TiN lattice growth, resulting in a decrease in the grain size from 60 nm in TiN to 25 nm at 20.6% Ni. The film with a Ni content of 12.4 at.% forms a nanocomposite structure in which the nanocrystalline TiN phase (nc-TiN) is surrounded by the amorphous Ni (a-Ni) phase. The formation of nc-TiN/a-Ni nanocomposite structures relies on the good wettability of Ni on TiN ceramics. The hardness and elastic modulus of the film gradually decrease with the increase in Ni content, but the toughness is improved. The hardness and elastic modulus decrease from 19.9 GPa and 239.5 GPa for TiN film to 15.4 GPa and 223 GPa at 20.6 at.% Ni film, respectively, while the fracture toughness increases from 1.5 MPa·m1/2 to 2.0 MPa·m1/2. The soft and ductile Ni phase enriched at the TiN grain boundaries hinders the propagation of cracks in the TiN phase, resulting in a significant increase in the film's toughness. The research results of this paper provide support for the design of TiN-Ni films with high strength and toughness and the understanding of the formation mechanism of nanocomposite structures. [ABSTRACT FROM AUTHOR]

This paper considers the peculiarities of the lexicographic fixation of nationally marked units of minority languages in Scotland, in particular Scots and Scottish Gaelic. The aim of this paper is to analyse dictionary entries and to determine the features of lexicographic representation of nationally-marked units at the microstructural level by identifying common and distinctive features. The source base is represented by such online dictionaries as The Dictionaries of Scots Language and Am Faclair Beag. The paper presents a brief overview of the creation of dictionaries, which constitute the source base of the research, and also provides a brief overview of their macrostrcture. The common features include the presence of interpretation (translation), transcription and grammatical commentary, while the differences include different formats of illustrating the usage of a lexical item (territorial - in Scottish Gaelic, situational - in Scots). Methods used in the study: general scientific (analysis and synthesis), critical dictionary research, diachronic and synchronic methods. [ABSTRACT FROM AUTHOR]

In the present work, we report a thermoresponsive hydrogel formed by the self-assembly of compounds 1 and 2 Milli Q water. Both hydrogels showed thixotropic behavior. Atomic force microscopy (AFM) studies confirm the fiber-like microstructure of compounds 1 and 2, but denser fibers were observed in the case of compound 1. The hydrogel formed by compound 1 detected Cu2+, Fe3+, and Hg2+, whereas the hydrogel of 2 showed a change in the optical signal, specifically upon adding Cu2+ and Hg2+. Mechanistically, adding metal ions to the hydrogel resulted in the formation of a (1:1) complex with Fe3+ and Hg2+ and (2:1) with Cu2+. The detection of metal ions has also been achieved in real-life samples, such as in tap water. Low-cost portable gel-coated paper strips have also been developed for the onsite detection of these metal ions. [ABSTRACT FROM AUTHOR]

Conventional book casting of Sm2TM17-type alloys (where TM = Co, Fe, Cu, Zr) leads to a coarse, highly segregated microstructure, predominantly due to the slow, variable cooling rate from the mould surface towards the centre of the ingot. These cast alloys require a long homogenisation treatment to remove this segregation and develop a super-saturated, metastable SmTM7-type hexagonal phase. This SmTM7 phase is a vital precursor phase required during magnet production to develop the complex cellular structure responsible for high magnetic properties. In this work, strip casting was employed to facilitate rapid solidification to develop thin flakes (<0.5 mm thick) with a columnar grain structure. Rapid cooling has the potential to produce a homogenous microstructure consisting predominantly of the metastable SmTM7 phase. This could remove or significantly reduce the need for the energy-intensive homogenisation treatment usually required in conventional magnet manufacture. This paper investigates the effect of wheel speed (and hence cooling rate) on flake thickness, microstructure, and phase balance of the cast alloys. It was shown that for wheel speeds between 1.1 and 3.0 m/s, the microstructure showed large variation; however, in all cases, evidence of the columnar SmTM7 phase was presented. The adhesion between the melt and the wheel was deemed to be critical for the nucleation and subsequent columnar growth of SmTM7 grains, where the wheel speed controlled both the flow of the alloy onto the wheel and the thickness of the resultant flake. It was determined that in order to achieve a homogenous columnar SmTM7 structure, the maximum flake thickness should be limited to 270 μm to avoid the formation of equiaxed Sm2TM17 grains through insufficient cooling. [ABSTRACT FROM AUTHOR]

A polarized light microscope (PLM) was utilized to examine the optical textures of mesophase pitch (MP) and MP-derived fibers, which aimed to reveal the arrangement and orientation characteristics of pitch molecules and to clarify the evolution and transformation mechanism of carbonaceous microcrystalline from pitch fibers to graphitized fibers. The results found that there were distinct optical textures in MP, where one side exhibited a transition from a flattening plane to a mountain-like undulating plane. This transition corresponded to the arrangement of pitch molecules, resembling stacked lamellar structures reminiscent of curved paper. Meanwhile, the optical textures of fibers revealed that the blue substance was wrapped around the red grain-like domains in the longitudinal section and confirmed that the red part belonged to the pyridine insoluble fraction of MP and the blue part belonged to its pyridine-soluble fraction. After graphitization, the red part was transformed into graphite sheets and the blue part was transformed into an amorphous carbon layer which was wrapped around the graphite sheets, forming a carbonaceous microcrystalline package-like bag. Therefore, this study provided a comprehensive interpretation of the structural evolution mechanism of MP and MP-derived fibers based on their macro-optical textures and micro-nanostructures. [ABSTRACT FROM AUTHOR]

This review paper offers a comprehensive analysis of the cold metal transfer (CMT) welding process in the context of similar metals and alloys. With a focus on recent advancements and key research contributions, the paper synthesizes a wealth of information to provide an understanding of the technique's applicability and potential in welding similar metals and alloys. By delving into the intricate interplay of process parameters, such as welding current, wire feed speed and shielding gas composition, the paper elucidates their influence on critical aspects of weld quality, including bead morphology, microstructure, and mechanical properties. In summation, this review consolidates the collective knowledge surrounding CMT welding of similar metals and alloys, providing researchers, practitioners, and industries with a comprehensive resource to navigate the intricacies of this technique. As the industrial landscape seeks to elevate welding standards, minimize post-weld processing, and optimize resource utilization, the insights presented in this review pave the way for the continued evolution and widespread adoption of CMT welding in the field of similar metals and alloys. [ABSTRACT FROM AUTHOR]

P92 steel is a modern martensitic heat-resistant steel currently used for seamless products for pressure equipment operating in supercritical operating parameters. The paper presents the results of a study on the strength properties and structure of a P92 steel welded joint used for pressure components of power units. The paper presents an assessment of the suitability for further operation of both the parent material and a circumferential similar welded joint of finished products in the form of P92 steel pipes after annealing for 3000 hours at 600 and 650°C. Annealing at 650°C results in faster increase in the size of the precipitates and their coagulation along grain boundaries of former austenite and martensite laths. The changes in mechanical properties were compared in relation to the state of the structure of the parent material and the material of the welded joint. Quantitative analysis of M23C6 precipitates was also carried out. [ABSTRACT FROM AUTHOR]

A novel Timoshenko beam model enriched to account for dissipation in cement-based materials was presented in this paper. The model introduced a new variable representing the relative sliding inside microcracks within the material. In the paper, the microcrack density was not supposed to increase, assuming a small deformation regime that implied no damage growth. The model utilized an expanded version of the principle of virtual work whose contributions came from external forces, internal elastic forces, and dissipation due to the microcrack's microstructure. The elastic energy included terms related to microcrack sliding and micro-macro interactions, accounting for nonlinearity in the material behavior. Numerical simulations, conducted using the finite element method, evaluated the mechanical properties of cement-based materials under three-point flexural tests and compression tests. These tests enabled the assessment of the material dissipative behavior under cyclic loading. Results showed dissipated energy cycles and mechanical responses influenced by the microcrack mechanics. Additionally, a parametric study, varying the friction force amplitude, revealed its impact on dissipated energy. The study highlighted a non-monotonic relationship between friction force amplitude and dissipated energy, with an optimal value maximizing dissipation. Overall, the model provided insights into the mechanics of cement-based materials, particularly regarding dissipation, which was essential for understanding their behavior in structural applications. [ABSTRACT FROM AUTHOR]

The cellular automata (CA) method has played an important role in the research and development of metallic materials. CA can interpret the microstructure changes of materials and obtain more abundant, accurate and intuitive information of microstructure evolution than conventional methods. CA can visually represent the process of grain formation, growth, development and change to us in a graphical way, which can assist us in analysis, thinking and solving problems. In the last five years, the application of CA in materials research has been rapidly developed, and CA has begun to occupy an increasingly important position in the simulation research of metallic materials. After introducing the advantages and limitations of CA compared to other widely used simulation methods, the purpose of this paper is to review the recent application progress on the microstructure simulation of metallic materials using CA, such as solidification, recrystallization, phase transformation and carbide precipitation occurring during forming and heat treatment. Specifically, recent research advances on microstructure simulation by CA in the fields of additive manufacturing, welding, asymmetrical rolling, corrosion prevention, etc., are also elaborated in this paper. Furthermore, this paper points out the future work direction of CA simulation in the research of metallic materials, especially in the simulation of the crystal structure, the prediction of mechanical properties, CA simulation software and rule systems, etc. These are expected to attract wide attention of researchers in the field of metallic materials and promote the development of CA in materials research. [ABSTRACT FROM AUTHOR]

Medium- and high-entropy alloys (MEAs/HEAs) or multi-principal element alloys are a new class of promising alloys with wide application possibilities in several industries like nuclear, offshore, liquefied natural gas, and transportation, among others. The development of these revolutionary alloys comes with the need to separately unravel their weldability as the microstructure and the welding-induced thermal responses of the single, dual, and multi-phase HEAs differ. Detailed knowledge of the weldability of MEAs/HEAs is still at the early stage and remains a useful link between the developed MEAs/HEAs and their full-scale industrial manufacturing applications. The intense heat input of fusion welding techniques easily introduces different or combined challenges such as elemental segregation, inhomogeneous phase transformation, solidification cracking, and coarsened structure to the weld metals of HEAs. As a result, this paper provides a state-of-the-art review of the low heat-input or solid-state welding and friction stir processing of MEAs/HEAs. The welding section covers explosive and friction stir welding processes of HEAs. Insights into the future research areas that can further progress the scientific understanding and weldability of MEAs/HEAs are briefly explicated in this paper. [ABSTRACT FROM AUTHOR]

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Laser powder bed fusion (LPBF) process has a great ability to produce complex AlSi10Mg 3D components with uncommon degrees of freedom for broad span of applications in different industries. Presence of the microstructural imperfections such as porosity, dependent on the parameters of the process can be detrimental to the printed products for different engineering applications. Parameters of the process and different post-processing heat and surface treatments are recognized for decrease of the occurrence of microstructural defects and for the improvement of the mechanical properties. The influence of laser power by applying four different laser speeds at one layer thickness with a constant hatch distance, on the microstructure and microhardness of the AlSi10Mg alloy was examined in this paper. The goal of the research was to determine whether increasing the laser speed will have a significant impact on the change in microstructure and the appearance of porosity in the tested samples. [ABSTRACT FROM AUTHOR]

To keep up with the pace of renewable energy, PV Emulators are encouraged during the design and installation stages. Short circuit current, maximum power point and open circuit voltage are required to analyze the complete characteristic plot of PV panel. This paper focuses on the modeling and control of PV Emulators, as well as the comparison of the results obtained by implementing P,PI, PID and FOPID as conventional controllers with AI-based PSOPI, PSOPID and ANFIS controllers. This work will aid in minimizing time, cost and on-site constraints, allowing timely installation of PV panels after covid. Another distinguishing feature of this paper is the comparative analysis of designed models with various control strategies and their associated performance indices over complete range of PV characteristics. [ABSTRACT FROM AUTHOR]

Refractory High entropy alloy (RHEA) is a potential material for coating gas turbine blades and pipeline due to its high-temperature mechanical and chemical properties. In this paper, a series of new NbTiCrFeMoX (x = 0.2, 0.4, 0.6, 0.8, 1) RHEAs were coated on GTD-111 nickel base superalloy by the laser cladding method. The effects of the Mo amount on the microstructure and tensile, creep, corrosion, and wear properties were investigated. XRD results showed that the microstructure of all five coatings included the B2 regular phase, the BCC irregular phase, C14-Laves (FeTi2), and C15-Laves (Cr2Nb). However, with the increase of Mo from 0.2 to 1, the amount of the BCC phase increased from 24.1 to 29.5%, the C14 phase increased from 55.1 to 61.4%, and the amount of the C15 phase decreased from 11.2 to 1.8%. The yield strength increased by increasing the volume fraction of BCC and C14-Laves phases from 328 MPa for the Mo0.2 sample to 685 MPa for the Mo1 specimen. The same factor increased the creep life of RHEA from 43 to 54 h under a force of 450 N and temperature of 800 °C by increasing the places of dislocation locking. The simultaneous presence of the BCC solid solution and Laves phase was one of the factors that reduced the coefficient of friction during the wear test from 0.63 to 0.44 with increasing Mo. Electrochemical tests in 3.5 wt% NaCl solution showed that the RHEAs showed significant corrosion resistance. Specimen Mo1 with the smallest Icorr (1.6103 × 10–6 A cm2) and the highest Ecorr (− 1.2025 V) showed the best corrosion resistance. [ABSTRACT FROM AUTHOR]

The low water/binder ratio of ultra-high performance concrete (UHPC) often results in its high autogenous shrinkage. Our study explored the effect of the single or binary addition of a CaO-based expansive agent (CEA) and steel fibers on flowability, compressive strength, flexural strength, microstructure, and autogenous shrinkage of UHPC. X-ray diffraction (XRD), thermogravimetric (TG) analysis, scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP) were applied to reveal the effects of CEA and steel fibers on hydration products and microstructure characteristics of UHPC. Experimental results show that the autogenous shrinkage of UHPC decreased markedly with the single or binary addition of CEA and steel fibers. Relative to the control group, autogenous shrinkage of UHPC with 2.5% dosage of single steel fibers, 6% dosage of single CEA, and binary addition of 2.5% steel fibers and 6% CEA decreased 17.8%, 10.9%, and 30.8% at 180 days, respectively. Steel fibers could enhance the mechanical performance of UHPC; nevertheless, they would decrease the flowability of UHPC. Meanwhile, the addition of CEA in the UHPC mixture not only maintained the mechanical properties and flowability but also decreased the autogenous shrinkage. Diffraction peak intensity and endothermic peak of Ca(OH)2 and the pore volume of 10-50 nm diminished with the content of CEA; however, that of C-S-H gel and ettringite increased. The prediction accuracy of nine shrinkage models (FHWA model, Lee model, Yoo model, JSCE model, B4 model, JonassonH model, Eurocode 2 model, CEB model, and DilgerW model) is analyzed with RE, R²new, and autogenous shrinkage of UHPC in this paper. [ABSTRACT FROM AUTHOR]

In this paper, Fe2TiAl–Fe2Ti alloy was prepared by arc melting method, and its corrosion and tribocorrosion behaviors were investigated in detail. The results showed that Fe2TiAl–Fe2Ti alloy exhibited better corrosion and tribocorrosion resistance compared to 0Cr18Ni9 stainless steel in 0.5 mol/L H2SO4 solution due to the formation of TiO2–Al2O3–Fe2O3 protective layer on the surface. Compared to static corrosion, the alloy exhibits a lower corrosion potential, higher corrosion current, and noticeable fluctuations in the polarization curves under sliding conditions. With the onset of sliding, the OCP value of the alloy decreases and the current density increases, with an inversely varying relationship between the friction coefficient and the OCP, indicating a significant wear-accelerated corrosion effect. At higher potentials, the wear volume of Fe2TiAl–Fe2Ti alloy and 0Cr18Ni9 stainless steel increases, indicating that corrosion accelerates wear. [ABSTRACT FROM AUTHOR]

Producing defect-free and high-quality welds are still challenging by the friction stir welding process. In this paper, ZrO2 nanoparticles of 20 nm average size were used in the weld area of Aluminium 8011 alloy. Three different types of tool profiles semi-circular, plus tool and trapezium profiles were used for better material mixing and improved joint strength. All of the experiments were performed with rotational speeds of 1800, 1120, and 560 RPM, and a constant welding speed of 25 mm/min. It was observed that there is no significant effect of the ZrO2 addition in the weld area. On the other hand, tool profile plays a great role in increasing tensile strength. The maximum tensile strength of 116.70 MPa was obtained with the semi-circular tool at 1800 RPM and 25 mm/min welding speed because of the improved material mixing and defect-free joint. [ABSTRACT FROM AUTHOR]

This research paper investigates the effectiveness of shielded metal arc welding (SMAW) and flux‐cored arc welding (FCAW) on mild steel substrates for chromium–boron hardfacing. Chromium–boron alloys are hard‐wearing and corrosion‐resistant materials used in industries where wear resistance is critical. The study aims to identify the best welding technique for increasing surface hardness and wear resistance. Standard test specimens were chosen and deposited using SMAW and FCAW processes. SMAW uses an electrode covered with flux, which turns into a sticky state when heated, while FCAW uses a core wire fabricated from flux, which generates a shielded gas upon melting. The effectiveness of each welding technique is assessed based on deposition efficiency, dilution rate, microstructure, hardness distribution, and wear resistance. This research helps industries choose the most efficient material and method for improving wear and corrosion resistance in applications like mining, construction, agriculture, and manufacturing. On average, FCAW offers a 1.67% improvement in hardness and 28.12% improvement in mass loss reduction when compared to SMAW. [ABSTRACT FROM AUTHOR]

To enhance the application of alkali-activated materials in mine filling, cemented tailings backfill was prepared using slag, fly ash, sodium silicate, and NaOH as primary constituents. The effects of the raw material type and dosage on the backfill were examined through a single-factor experiment. Additionally, response surface methodology (RSM) was utilized to optimize the mixing ratios of the backfill, with a focus on fluidity and compressive strength as key objectives. The evolution of backfill quality and compressive strength under the combined effects of dry–wet and freeze–thaw (DW-FT) cycles was analyzed. The hydration products, microstructure, and pore characteristics of the specimens were analyzed using X-ray diffraction (XRD), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), and nitrogen adsorption tests (NATs) across varying cycles. The results demonstrate that the optimal backfill composition includes 47.8% fly ash, 6.10% alkali equivalent, and a 1.44 sodium silicate modulus. The macroscopic behavior of the backfill under DW-FT coupling followed this progression: pore initiation → pore expansion → crack formation → crack propagation → structural damage. After a minor initial increase, the backfill strength steadily decreased. Microscopic analysis revealed that the decline in internal cementation products and the deterioration of pore structure were the primary causes of this strength reduction. Thus, the DW-FT coupling can cause significant erosion of the backfill. The technical solutions presented in this paper offer a reference for solid waste utilization and provide valuable insights into the durability of backfill under DW-FT coupling. [ABSTRACT FROM AUTHOR]

This paper presents an approach to evaluate the failure of arbitrarily inclined interfaces using FE models with structured spatial discretization, providing accurate prediction of crack propagation along paths known a priori that are not constrained to the element boundaries. The combination of algorithms for the generation of structured discretization of representative polycrystalline microstructures with novel cohesive element formulations allow modelling the failure of complex topologies along rasterised boundaries, with noticeably higher computational efficiency and comparable accuracy. Two formulations of raster cohesive elements are presented, adopting either elastic-brittle or Tvergaard–Hutchinson traction separation laws. The formulations proposed are first validated comparing the failure of the interface within bi-crystal structures discretised using hexahedral elements either within a structured mesh (i.e. with rasterised boundaries) or an unstructured mesh (i.e. with planar boundary). Subsequently, the effectiveness of the formulations is demonstrated comparing the inter-granular crack propagation within complex polycrystalline microstructures. The behaviour of the novel cohesive element formulation in structured meshes consisting of regular hexahedral elements is in excellent agreement with the deformation and failure of classic cohesive element formulations placed along the planar boundaries of unstructured meshes consisting of tetrahedral elements. The higher computational cost of the raster cohesive elements is more than compensated by the increase in computational efficiency of structured meshes when compared to unstructured meshes, leading to a reduction of the simulation time of up to over 200 times for the simulations presented in the paper, thus allowing the simulation of large domains. [ABSTRACT FROM AUTHOR]

Tin-based Babbitt alloys are a widely used bearing bushing material which have good comprehensive properties. However, problems such as high-temperature softening and insufficient bearing capacity occur during their use, so the optimization of tin-based Babbitt alloys has become a research hotspot. In this paper, ZChSnSb11-6 alloy was mainly prepared by the gravity casting method, and different amounts of Zn were added to the alloy (the mass fraction values were 0 wt.%, 0.05 wt.%, 0.1 wt.%, 0.15 wt.%, and 0.2 wt.%, respectively). Through the hardness test, the tensile test, the friction and wear test, and the microstructure observation of the prepared alloy, the influence of Zn on the organization and properties of the ZChSnSb11-6 alloy was analyzed. The results show that the size of the SnSb hard phase changed with the increasing content of Zn. The size of the hard phase of the SnSb tended to increase first and then decrease, and the number of phase particles increased first and then decreased, resulting in changes in performance. Through comparison, it was learned that the addition of Zn can effectively improve the hardness, tensile strength, yield strength, and wear resistance of the alloy, but the elongation rate was reduced. When the Zn content was 0.1 wt.%, the hardness value of the alloy reached the maximum value, 25.82 HB, which increased by 7.3% when compared with the sample without Zn. The hardness of the Zn, 0.15 wt.%, is close to that of the Zn, 0.1 wt.%. Compared to the sample without Zn, the tensile strength and elongation of the alloy were maximized at a Zn content of 0.15 wt.%. Compared to the sample without the Zn, the tensile strength was increased by 21.29%, and the elongation rate was increased by 46%. An analysis showed that the alloy has good comprehensive mechanical properties when the Zn content is 0.15 wt.%. [ABSTRACT FROM AUTHOR]

P92 steel is widely used in ultra-supercritical units due to its excellent high-temperature performance. This paper studies the microstructure of P92 steel steam pipes in three conditions: as-supplied, after 80,000 h of service at 67.06 MPa stress, and after 100,000 h of service at 80.28 MPa stress. After prolonged service, the P92 steel retains its martensitic structure, but the lath width increases and the dislocation density decreases. In addition to M23C6, MX, and Laves phases, Z phase was also observed among the precipitates. The results indicate that the sizes of M23C6 and Laves phases increase with the progression of creep life consumption, with the coarsening rate of Laves phase being significantly higher than that of M23C6. However, the coarsening of MX phase is not evident. Compared to the Laves phase, the formation of the Z phase requires a longer period of time. The precipitation of the Z phase consumes MX carbonitrides, and it has been observed that the Z phase precipitates from the MX phase, with the two phases exhibiting a coexisting state. [ABSTRACT FROM AUTHOR]

The influence of laser beam welding parameters (power, welding rate, focusing, head oscillation, shielding gas) on the microstructure, mechanical properties and corrosion resistance of the super-duplex stainless steel SAF 2507 was studied in this paper. The presented results clearly report the effects of welding parameter changes on the character of the steel's microstructure. The presence of secondary phase M2N in weld metals has an important influence on their mechanical properties. Optimal mechanical properties, an acceptable ferrite/austenite ratio, and the minimum content of M2N nitride required in the weld metal were acquired in the case the following application: 1100 W power, welding speed of 10 mm/s, focusing of 4 mm, and pure nitrogen shielding gas (20 L/min). [ABSTRACT FROM AUTHOR]

This paper investigates the microstructure, texture, and mechanical properties of the Mg-4Zn-1Mn-0.5Ca alloy subjected to hot extrusion under varying conditions of temperature (260 °C, 300 °C, 340 °C) and extrusion speed (0.01 mm/s, 0.1 mm/s, 1 mm/s). The primary objective is to determine the optimal extrusion parameters within the selected experimental range for achieving superior mechanical properties. The results indicate that, when extruded at a constant speed of 0.1 mm/s, the alloy exhibits optimal performance at 340 °C, with a yield strength of 202 MPa, ultimate tensile strength (UTS) of 306 MPa, and elongation at fracture of 18.9%. A decrease in extrusion temperature leads to an increase in yield strength but a reduction in ductility. Specifically, the UTS reaches its peak at 342 MPa at 300 °C, while it drops slightly to 329 MPa at 260 °C. The final results show that the comprehensive mechanical properties of the Mg-4Zn-1Mn-0.5Ca alloy obtained by hot extrusion treatment with an extrusion temperature of 300 °C and extrusion speed of 0.1 mm/s are the best and can effectively improve the mechanical properties of the alloy and provide a good choice for the preparation of other biodegradable magnesium alloy products. [ABSTRACT FROM AUTHOR]

This paper investigated the FeCoCrNiAl high-entropy alloy on H13 steel, prepared using laser cladding, to improve the elevated-temperature wear resistance of the alloy. The results revealed that FCC and BCC phases, in terms of the coating, produced a large dislocation density. The coating exhibited a columnar and equiaxed crystal microstructure. With the comprehensive effects of fine-grain strengthening, solid solution strengthening, and dislocation strengthening, the average hardness of the coating (500 HV0.1) was improved by 150% compared with that of H13 steel (200 HV0.1). The wear experiments were conducted at 623 K, 723 K, and 823 K. Compared with H13 steel, the wear volume of the coating decreased by 59.20%, 70.79%, and 78.20% under different temperatures. The wear forms impacting the coating were mainly abrasive wear and oxidation wear. However, H13 steel presented adhesive wear and fatigue wear, in addition to abrasive wear and oxidation wear. [ABSTRACT FROM AUTHOR]

In this paper, Fe-3%Si ultra-thin ribbons prepared by the planar flow casting (PFC) technique were subjected to temper rolling and annealing treatments. The microstructure and texture evolution during this process were examined through experimental measurements coupled with crystal plasticity finite element (CPFE) simulation to assess the feasibility of preparing ultra-thin non-oriented silicon steel using PFC ribbons. The results indicate that the PFC ribbons exhibit a significant columnar crystal structure, and {001}-oriented grains comprise over 30%. After being annealed, the grains with different orientations grew uniformly, the texture components were basically unchanged, and the {001} texture was well preserved. When annealing was carried out after temper rolling with a reduction rate of 7%, uneven grain growth was observed, and the growth tendency of the {001} grains, especially, surpassed that of the {111} grains, with an elevated temperature which peaked at 950 °C, where the proportion of {001} grains was maximal. When being annealed after temper rolling to 15%, grains of other orientations showed significant growth at each temperature, while the {001} grains did not show an obvious growth advantage. Utilizing the CPFE, the deformation-stored energy distribution of each characteristic-oriented grain was simulated, and it was shown that compared to the 15% rolling reduction rate, the deformation-stored energy accumulation of {001}-oriented grains after being rolled to 7% reduction was significantly lower than that of {111}-oriented grains. It suggests that the larger stored energy difference makes {001} grains show a stronger growth advantage based on the SIBM mechanism during annealing, after being rolled with a reduction rate of 7%. Overall, for the synergistic optimization of microstructure and texture, rolling with a 7% reduction rate followed by annealing at 950 °C in a hydrogen atmosphere is most advantageous. [ABSTRACT FROM AUTHOR]

Water-cooled wall tubes are susceptible to high-temperature corrosion during service. Applying high-performance coatings via laser cladding on the tube surfaces can significantly enhance corrosion resistance and extend the service life of the tubes, providing substantial economic advantages. This paper prepared Y2O3/IN625 composite coating by means of high-speed laser cladding. Furthermore, the effects of Y2O3 addition on the microstructure evolution, hardness, as well as the high-temperature corrosion behaviors have been systematically investigated. The results show that Y2O3 addition can effectively refine the microstructure of the Inconel 625 coating, but the phase composition has little change. The coating's hardness can also be improved by about 7.7%, reaching about 300 HV. Compared to Inconel 625 coating, the Y2O3-added composited coating shows superior high-temperature corrosion resistance, with the corrosion mass gain decreased by about 36.6%. The denser and tightly bonded Cr-rich oxides layer can be formed adjacent to the coating surface, which plays a predominant role in improving the coating corrosion resistance. [ABSTRACT FROM AUTHOR]

In order to explore the influence of laser power on the evolution of molten pool and convective heat transfer of laser cladding Incoloy 926 on stainless steel surface, a three-dimensional thermal fluid multi-field coupled laser cladding numerical model was established in this paper. The variation of latent heat during solid-liquid phase transformation was treated by apparent heat capacity method. The change in the gas–liquid interface was tracked using the mesh growth method in real time. The instantaneous evolution of temperature field and velocity flow field of laser cladding Incoloy 926 on a stainless steel surface under different laser power was discussed. The solidification characteristic parameters of the cladding layer were calculated based on the temperature-time variation curves at different nodes. The mechanism of the impact of laser power on the microstructure of the cladding layer was revealed. The experiment of laser cladding Incoloy 926 on 316L surface was carried out under different laser power. Combined with the numerical simulation results, the effects of laser power on the geometrical morphology, microstructure and element distribution of the cladding layer were compared and analyzed. The results show that with the increase in laser power, the peak temperature and flow velocity of the molten pool surface both increase significantly. The thermal influence of the molten pool center on the edge is enhanced. The temperature gradient, solidification rate, and cooling rate increased gradually. The microstructure parameters (G/R) are relatively small when the laser power is 1000 W. In the experimental range, the dilution rate and wetting angle of the cladding layer both increase with the increase in laser power. When the laser power is 1000 W, the alloying elements of the cladding layer are more evenly distributed and the microstructure is finer. The experimental results are in good agreement with the simulation results. [ABSTRACT FROM AUTHOR]

Lime stabilization is a sustainable technique due to its use of local materials, increased durability, reduced maintenance, and improved resistance to water action. This paper examines the impact of lime stabilization on the mechanical, microscopic, and mineralogical properties of a tropical soil. Two types of lime, calcitic and dolomitic, were tested at 3% and 5% by weight. Compressive, indirect tensile and flexural test results and statistical analysis revealed that calcitic lime mixtures had higher strength and stiffness, whereas dolomitic lime mixtures exhibited greater deformability with higher tensile strain at break. Scanning electron microscopy indicated that the soil's porous matrix closed within 7 days for both lime types due to flocculation, with increased matrix interlocking over time. The calcitic lime mixture developed a more closed matrix compared to the dolomitic lime, which showed weaker cementing. X-ray diffraction analysis indicated higher consumption of clay minerals and a notable reduction in calcium hydroxide peaks in the lime-treated soils. The study concludes that calcitic lime provides better pavement performance for stabilizing the soil, enhancing its engineering properties while also being sustainable by reducing the need for raw material extraction and improving resilience to climate-related issues such as floods. [ABSTRACT FROM AUTHOR]

Yttrium barium copper oxide (YBCO) is used for special applications in linear generators because of its excitation loss, lower weight, and higher efficiency. These qualities enable the compound to operate better than the conventional copper wire coil in the stator unit of the linear generator. However, the continuous use of YBCO in linear generators has a fundamental challenge that affects industrial production and material stability after prolonged use. This paper seeks to sustain the adoption of YBCO by improving its quality for linear generator applications. The yttrium cuprates modification (YBYbCO) was synthesized using the solid-state reaction technique by doping YBCO with ytterbium. The crystalline structure, microstructural pattern, and stability of the new sample were adequately measured and found to be structurally stable to ensure durability. It was reported that applying YBYbCO in the linear generator would lead to a 200% increase in energy generation. The higher number of particles and lower individual particulate resistance enable it to withstand chemical pressure, thereby prolonging the lifespan of the linear generator. [ABSTRACT FROM AUTHOR]

Cassava (Manihot esculenta Crantz) is one of the three major potato crops in the world. Consumption of cassava necessitates thermal processing, and the impact of such processing on the physicochemical and structural characteristics of cassava remained unknown. In this paper, three traditional thermal processing methods (boiling, steaming and frying) were used to heat-treat cassava. The physicochemical properties (chemical composition, pasting properties, thermal properties) and structural changes (microstructure, long-range ordering, and short-range ordering) of the processed cassava and untreated cassava was characterized by scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffractometer, and differential thermal scanning calorimetry. The findings indicated a significant reduction in the total starch content of cassava following diverse heat treatments, accompanied by a notable increase in amylose content (P<0.05). The relative crystallinity and short-range ordering of starch in cassava decreased, with a 74.35% decrease in crystal structure after frying and a 65.16% decrease in crystal structure after steaming. The effect of heat treatment on the gelatinization characteristics of cassava was significant: after heat treatment, the peak viscosity and disintegration value showed an overall upward trend, while the gelatinization temperature significantly decreased (P<0.05). Boiling and steaming treatments resulted in a 49.67% and 43.98% increase in recovery value, respectively, while frying treatment decreased by 23.25%. There were no significant differences observed in the thermal properties and infrared spectrum groups among cassava samples that underwent different heat treatments. Generally, steaming treatment exhibited minimal damage to the crystal structure of starch in cassava, boiling treatment enhanced its gel formation and susceptibility to aging while frying treatment demonstrated superior thermal stability. The results can serve as a theoretical reference for selecting appropriate heat processing methods for cassava in food applications and designing a variety of cassava products. [ABSTRACT FROM AUTHOR]

This paper investigates durability related properties of concretes containing copper heap leach residue (CHLR) as partial replacement of natural fine and coarse aggregates. The use of CHLR as aggregates in concretes promotes the reduction of the dependance on natural aggregates, upcycling of the waste as aggregates and the reduction of carbon footprint associated with natural aggregate productions. In this study, CHLR was washed, dried, and sieved to separate fine aggregate and coarse aggregate, and concretes were prepared with a cement content of 400 kg/m3 and water-cement ratio of 0.435 by replacing 25-75% natural fine and coarse aggregates. The concrete containing 50% CHLR as a partial replacement of natural CA and FA gained compressive strength of 52.9 and 54.0 MPa; drying shrinkage of 662 and 538 με; volume of permeable voids of 6.2 and 5.7%; 1485 and 2640 coulomb of charge passed in chloride permeability; and primary sorptivity coefficients of 4.0 × 10−3 and 4.3 × 10−3 mm/sec0.5 at 180 days, respectively. In contrast, these properties for the control specimens at the same age were 59.1 MPa, 394 με, 5.19%, 1280 coulomb, and 2.5 × 10−3 mm/sec0.5, respectively. The compressive strength and durability aspects declined in concretes using 75% CHLR coarse and fine aggregates. Existing analytical models for durability related properties of concrete containing natural aggregates are compared to that of the concretes using CHLR. Finally, backscattered electron images coupled with energy dispersive x-ray spectroscopy of the CHLR concretes were analyzed to understand the pore refinement, interfacial transition zones, microcracks, and hydration products influencing the durability aspects. [ABSTRACT FROM AUTHOR]

This paper employed squeeze-casting (SC) technology to develop a novel Al-7Si-1.5Cu-1.2Ni-0.4Mg-0.3Mn-0.15Ti heat-resistant alloy, addressing the issue of low room/high temperature elongation in traditional gravity casting (GC). Initially, the effects of SC and GC processes on the microstructure and properties of the alloy were investigated, followed by an examination of the evolution of the microstructure and properties of the SC samples over thermal exposure time. The results indicate that the SC process significantly improves the alloy's microstructure. Compared to the GC alloy, the secondary dendrite arm spacing of the as-cast SC alloy is refined from 50.5 μm to 18.5 μm. Meanwhile, the size and roundness of the eutectic Si phase in the T6-treated SC alloy are optimized from 11.7 μm and 0.75 μm to 9.5 μm and 0.85 μm, respectively, and casting defects such as porosity are reduced. Consequently, the ultimate tensile strengths (UTSs) at room temperature and at 250 °C of the SC alloy are 5% and 4.9% higher than that of GC alloy, respectively, and its elongation at both temperatures shows significant improvement. After thermal exposure at 250 °C for 120 h, the morphology of the residual second phase at the grain boundaries in the SC alloy becomes more rounded, but the eutectic Si and nano-precipitates undergo significant coarsening, resulting in a 49% decrease in UTS. [ABSTRACT FROM AUTHOR]

Magnesium sulphoaluminate (MSA) cement has good bonding properties and is suitable as an inorganic adhesive for repairing materials in civil engineering. However, there are still some problems with its use, such as its insufficient 1 day (d) strength and poor volumetric stability. This paper aims to investigate the influences of metakaolin (MK) on the physical and mechanical properties of magnesium sulphoaluminate (MSA) cement. The hydration products and microstructures of typical MSA cement samples were also analysed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The results showed that the addition of metakaolin reduces the fluidity and shortens the setting time of the MSA cement. The initial setting time and final setting time shortened maximally by 15–27 min and 25–48 min, respectively, with the addition of 10–30% metakaolin. Moreover, the compressive strength and flexural strength of the MSA cement improved significantly with the addition of 10–30% metakaolin at a curing age of 1 d. Compared with the compressive and flexural strengths of the control sample at 1 d, the compressive strengths of the modified samples showed obvious increases of 98%, 101%, and 109%, and the flexural strengths increased by 39%, 31%, and 26%, respectively, although they decreased slightly when the curing ages were 7 d, 14 d, and 28 d. The addition of 10% metakaolin improved the water resistance of the MSA cement immersed in water for 7 d and resulted in even higher water resistance at 28 d. The addition of 10–30% metakaolin improved the volumetric stability of the MSA cement with increasing dosages before 28 d of ageing. XRD and SEM-EDS analyses showed that the metakaolin accelerated the early hydration reaction and optimised the phase composition of the MSA cement. The results indicate that the addition of 10–20% metakaolin improved the strength after 1 d of ageing, water resistance, and volumetric stability of the MSA cement, providing theoretical support for the application of MAS cement as an inorganic bonding agent for repairing materials. [ABSTRACT FROM AUTHOR]

This paper presents selected results of theoretical and experimental research into the manufacture of axisymmetric bimetallic components using three-tool skew rolling technology. In the tests, it was assumed that the outer layer would be a material intended for heat treatment. However, low-carbon steel was used for the core. Experimental investigations were carried out in an innovative CNC skew rolling mill. Tests were carried out at different technological parameters of the process. In addition, the geometric parameters of the billet and the way it was heated were analyzed in relation to the quality of the resulting weld between the two materials. The quality of the weld was assessed based on metallographic observation and on strength tests (shear method). On the other hand, theoretical studies were based on numerical modeling (FEM). The numerical analysis made it possible to determine the distribution of temperature, deformation and stress in the rolling bimetallic component. The results obtained indicated that it is possible to produce bimetallic materials from the proposed steel grades. In addition, a significant effect of the method of heating the billet in the chamber furnace on the microstructure in the joining zone and the shear strength was found. There was an increase in Rc strength of about 35% when using oxidation protection. The results indicated better strength when the billet is rolling with a smaller outer layer thickness (about 50 MPa). This was confirmed by the results obtained from the FEM analysis, which indicated higher values of plastic strain and the occurrence of higher compressive stresses in the near-surface zones of the rolled bimetallic forging, both of which facilitate the welding process. From the temperature distribution (in the range of (600–1200) °C) obtained during the rolling of the bimetal forging, it can be seen that contact with cold tools does not affect the temperature in the welding zone. [ABSTRACT FROM AUTHOR]

In order to prepare coating with good friction and wear resistance at elevated temperature on the surface of hot-working tool steel, by using a CO2 laser, FeCrNiTiZr high-entropy alloy coating with different laser scanning speeds (360, 480 and 600 mm/min, respectively) was successfully fabricated by using laser cladding technology on the surface of H13 steel in this paper. Phase constitutions, microhardness, microstructure, and wear characteristics of FeCrNiTiZr coatings under different laser scanning speeds were analyzed. It was determined that 480 mm/min was the optimal laser scanning speed. The results showed that the coating at the scanning speed of 480 mm/min consists of a BCC phase with significant lattice distortion and high dislocation density; the crystal structure is cellular crystal and dendrite crystal. The coating demonstrates the highest microhardness (842 HV0.2), which is 4.2 times that of the substrate (200 HV0.2). Its average friction coefficients at room temperature and 823 K are approximately one-seventh and one-third of the substrate's, respectively, and its wear volume is reduced by about 98% and 81% under these conditions. Compared to the substrate, the coating underwent slight abrasive wear, adhesive wear, and oxidative wear at both room temperature and 823 K. In contrast, the substrate underwent severe abrasive wear, adhesive wear, oxidative wear, and even fatigue wear. [ABSTRACT FROM AUTHOR]

This paper proposes a Topology Optimization (TO) method for the design of microstructures within All-Solid-State Batteries (ASSBs), using the homogenization method. ASSBs have attracted significant attention because of their possibilities to surpass the problems of conventional liquid lithium-ion batteries regarding safety, energy density, and longevity. To improve the performance of ASSBs, many experimental research results based on costly trial-and-error approaches have previously been presented. In order to mitigate the cost and time involved in trial-and-error, several numerical approaches have also been proposed to deal with the multiple materials in various batteries. TO is one of the most flexible structural optimization methods that can allow topological changes as well as boundary changes, and has the potential to provide high-performance structures. TO methods have also been successfully applied to the design of several kinds of batteries, such as Solid Oxide Fuel Cells (SOFC) and Redox flow batteries. However, to the best of our knowledge, research concerning the structural optimization of ASSBs has not been found. In this paper, we propose the TO method targeting microstructure designs of ASSBs using the homogenization method to associate microstructural configurations and macroscopic properties. First, we define a new objective function that can appropriately evaluate the performance of ASSBs and can reduce computational costs in the optimization process. Next, the design sensitivities addressing the time-dependent and nonlinear aspects of the problem are derived using the Lagrange and continuous adjoint methods. Finally, we provide several numerical results under various conditions, including different C-rates, to confirm the validity and efficiency of our proposed method. [ABSTRACT FROM AUTHOR]

The ceramic materials studied in this paper consist of finely dispersed crystalline phases embedded in a glassy matrix, which is similar to glass-ceramic materials, porcelain, and VC products. The strength depends then not only on the properties of the individual crystalline phases but also on their interactions and the matrix. Differences in mechanical properties for materials with similar chemical compositions are most likely related to diverging microstructures. Crystal orientation, grain-size distribution and shape, the ratio of the glass matrix to the crystalline phase, and homogeneity control the flexural strength of glass-ceramic materials. The subject of the study is whiteware ceramic materials from the SiO 2 –Al 2 O 3 –Na 2 O–K 2 O–MgO–SrO system, fired similarly to the regime used for VC products. The effect of the type of alkali oxide and the share of SrO were tested. This paper presents the results of hot-stage microscopy, X-ray diffraction (XRD), scanning electron microscopy with a micro-analyzer (SEM-EDS) and biaxial flexural strength measurements. Additionally, nanoindentation technique was used to access local mechanical properties. [ABSTRACT FROM AUTHOR]

The preparation of coordination polymers with good room temperature phosphorescence is the focus of current research. In this paper, zinc and cadmium were used as metal ions and 2,3-pyridinedicarboxylic acid (H2L = 2,3-pyridinedicarboxylic acid) was used as organic ligands to successfully synthesize Cd (II) homometallic [CdL]·H2O and Zn(II)Cd(II) heterometallic [ZnCdL2]·DMF·5H2O coordination polymers microstructures. In addition, morphology, powder X-ray diffraction (PXRD), infrared spectroscopy (IR), elemental analyses, thermogravimetric analysis (TGA) and their luminescence properties were studied. Cd-CP is a micron-sized spherical structure, while Zn/Cd-CP is a flower-like structure formed by the accumulation of sheets. The results show that Cd(II) homo- and Zn(II)Cd(II) heterometallic coordination polymers have quantum yields of 10.05% and 8.54%, respectively. It is worth noting that the lifetime of Cd-CP is 124.62 ms, while the lifetime of Zn/Cd-CP is significantly extended to 363.09 ms after doping with metal ion Zn2+. The phosphorescent lifetime of coordination polymers was improved by the heterometallic doping strategy, which provided a new idea and method for the preparation of coordination polymers with long-lived room temperature phosphorescent properties. In addition, the two coordination polymers exhibited blue and cyan fluorescence at 365 nm UV light, respectively, and a green afterglow of about 2 s could be observed with the naked eye when the UV lamp was turned off. [ABSTRACT FROM AUTHOR]

Al and Mg alloy high pressure die castings (HPDC) are increasingly used in automotive industries. The microstructures in the castings have decisive effect on the casting mechanical properties, in which the microstructure characteristics are fundamental for the investigation of the microstructure-property relation. During the past decade, the microstructure characteristics of HPDC Al and Mg alloys, especially micro-pores and α-Fe, have been investigated from two-dimensional (2D) to threedimensional with X-ray micro-computed tomography (μ-CT). This paper provides an overview of the current understanding regarding the 3D characteristics and formation mechanisms of microstructures in HPDC alloys, their spatial distributions, and the impact on mechanical properties. Additionally, it outlines future research directions for the formation and control of heterogeneous microstructures in HPDC alloys. [ABSTRACT FROM AUTHOR]

Ultra-large aluminum shape castings have been increasingly used in automotive vehicles, particularly in electric vehicles for light-weighting and vehicle manufacturing cost reduction. As most of them are structural components subject to both quasi-static, dynamic and cyclic loading, the quality and quantifiable performance of the ultra-large aluminum shape castings is critical to their success in both design and manufacturing. This paper briefly reviews some application examples of ultra-large aluminum castings in automotive industry and outlines their advantages and benefits. Factors affecting quality, microstructure and mechanical properties of ultra-large aluminum castings are evaluated and discussed as aluminum shape casting processing is very complex and often involves many competing mechanisms, multi-physics phenomena, and potentially large uncertainties that significantly influence the casting quality and performance. Metallurgical analysis and mechanical property assessment of an ultra-large aluminum shape casting are presented. Challenges are highlighted and suggestions are made for robust design and manufacturing of ultra-large aluminum castings. [ABSTRACT FROM AUTHOR]

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