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Carbon fibre-reinforced ultra-high temperature ceramics (UHTCs) are considered a class of promising materials for several applications, the most appealing ones being in the aerospace sector. Reinforcement is necessary to overcome the brittleness and low thermal shock resistance of ceramics and is often provided through the addition of carbon fibres or other carbon-based phases, such as nanotubes, graphene, and graphite. The present work is focused on the toughening of UHTCs through incorporation of 30−50 vol% thin, ordered graphite layers from conventional filter paper followed by hot pressing sintering. Cellulose filter paper was selected because it undergoes thermolysis with no melting stage forming a strong carbonaceous residue that can be used as toughener. Microstructure and mechanical properties of toughened composites were compared to those of other materials reinforced with short carbon fibres and the effect of different distribution of graphite was studied. Addition of graphite allowed toughness to be increased from 3−4 MPa·m1/2 (for un-reinforced materials) to 5.1−5.5 MPa·m1/2, similar to results obtained with short fibre reinforcement. The high-temperature properties, such as strength and toughness as well as oxidation resistance at 1500 ℃, were also examined.

In this work, stacked SiC fibers paper‐reinforced SiC ceramic matrix composites (SiCnf/SiC CMCs) were prepared by nanoimpregnation and transient eutectic (NITE) process using ultra‐long single‐crystal SiC nanofibers. The effect of the SiCnf surface modification via boron nitride (BN) interphase deposition as well as the sintering additive (Al2O3–Y2O3) content on the density, microstructure, and mechanical properties of SiCnf/SiC CMCs has been investigated systematically. The results revealed that the laminated SiCnf/SiC CMCs feature a significant saw‐tooth‐like curve on the load–displacement test, which indicates that the obtained laminated structure with the weak interlayer binding owning to the BN coating treatment possesses significant toughening to the SiC ceramics. Specifically, the SiCnf/SiC CMCs with the sintering additive content of 12 wt% revealed a fracture toughness of over 10 MPa m1/2 after 60 min of BN interface deposition, which is 104.31% higher than that of the composites prepared without BN coating. [ABSTRACT FROM AUTHOR]

Expansive soil exhibits significant swellings and shrinkages, which may result in severe damage or the collapse of structures built upon it. Calcium-based admixtures, such as lime, are commonly used to improve this problematic soil. However, traditional chemical additions can increase significant environmental stress. This paper proposes a sustainable solution, namely, the use of lignin fiber (LF) from the paper industry to partially replace lime as an amendment for expansive soils. Both the macroscopic and microscopic characteristics of the lignin fiber-treated expansive soil are extensively studied. The results show that the mechanical properties of expansive soil are improved by using lignin fiber alone. Under the condition of an optimal dosage of 8%, the compressive strength of lignin fiber-modified soil can reach 193 kPa, the shear strength is increased by 40% compared with the untreated soil, and the water conductivity is also improved with the increase in dosage. In addition, compared with 2% lime-modified soil, the compressive strength of 8% lignin fiber- and 2% lime composite-treated expansive soil increased by 50%, the cohesion increased by 12%, and the water conductivity decreased significantly. The microstructure analysis shows that at an 8% lignin fiber content, lignin fibers interweave into a network in the soil, which effectively enhances the strength and stability of the improved soil. Simultaneously, the fibers can form bridges across the adjacent micropores, leading to the merging of pores and transforming fine, dispersed micropores into larger, connected macropores. Lime promotes the flocculation of soil particles, forming larger aggregates and thus resulting in larger pores. The addition of fibers exerts an inhibitory effect on the flocculation reaction in the composite-improved soil. In conclusion, lignin fibers are an effective addition used to partially replace calcium admixture for the treatment of expansive soil, which provides a sustainable and environmentally friendly treatment scheme for reducing industrial waste. [ABSTRACT FROM AUTHOR]

Expansive soil exhibits significant swellings and shrinkages, which may result in severe damage or the collapse of structures built upon it. Calcium-based admixtures, such as lime, are commonly used to improve this problematic soil. However, traditional chemical additions can increase significant environmental stress. This paper proposes a sustainable solution, namely, the use of lignin fiber (LF) from the paper industry to partially replace lime as an amendment for expansive soils. Both the macroscopic and microscopic characteristics of the lignin fiber-treated expansive soil are extensively studied. The results show that the mechanical properties of expansive soil are improved by using lignin fiber alone. Under the condition of an optimal dosage of 8%, the compressive strength of lignin fiber-modified soil can reach 193 kPa, the shear strength is increased by 40% compared with the untreated soil, and the water conductivity is also improved with the increase in dosage. In addition, compared with 2% lime-modified soil, the compressive strength of 8% lignin fiber- and 2% lime composite-treated expansive soil increased by 50%, the cohesion increased by 12%, and the water conductivity decreased significantly. The microstructure analysis shows that at an 8% lignin fiber content, lignin fibers interweave into a network in the soil, which effectively enhances the strength and stability of the improved soil. Simultaneously, the fibers can form bridges across the adjacent micropores, leading to the merging of pores and transforming fine, dispersed micropores into larger, connected macropores. Lime promotes the flocculation of soil particles, forming larger aggregates and thus resulting in larger pores. The addition of fibers exerts an inhibitory effect on the flocculation reaction in the composite-improved soil. In conclusion, lignin fibers are an effective addition used to partially replace calcium admixture for the treatment of expansive soil, which provides a sustainable and environmentally friendly treatment scheme for reducing industrial waste.

This paper describes the fabrication and characterization of porous SiC ceramics derived from highly-filled preceramic papers. The SiC ceramics were obtained by spark plasma sintering of stacked preceramic papers at temperatures of 2100 and 2200 °C under pressures of 5–60 MPa for 10 min. The microstructure and phase composition were analyzed by scanning electron microscopy and X-ray diffraction, respectively. Gas permeation tests were performed using hydrogen permeation cell at room temperature. It is revealed that the porosity of sintered SiC can be varied from 9 to 45 % depending on the sintering parameters. The shrinkage of the materials during spark plasma sintering occurs in four stages. The linear shrinkage value of the material increases from 7 to 47 % at 2100 °C and from 20 to 50 % for the samples sintered at 2100 and 2200 °C, respectively. Correlation dependencies between porosity and mechanical properties of the fabricated SiC were established. The obtained porous SiC ceramics exhibit high bending strength of 165 MPa and gas permeation flux of 78 molH 2 /m2/s at the porosity of 36 % that make it suitable for ceramic-based membranes. [ABSTRACT FROM AUTHOR]

Multi-walled carbon nanotubes (MWCNTs) are a high-quality interlamination reinforcement material, but the high viscosity of polyetheretherketone (PEEK) prevents good fusion between MWCNTs and PEEK. This study proposes a method to achieve the complete integration of MWCNTs and PEEK through the preparation of a composite film using the vacuum suction filtration (VSF) method and optimizes the process parameters. An orthogonal experiment with three factors (filter paper pore size, ultrasonic dispersion time, and PEEK content) at three levels is designed, and mechanical performance testing and microscopic morphology observation are conducted. The influence of the three factors of filter paper pore size, ultrasonic time, and PEEK content on the elastic modulus and tensile strength of the film is investigated. The results are a filter paper pore size of 0.45 μm, ultrasonic time of 8.3 h, and PEEK content of 336.524 mg. The mechanical performance obtained under the optimal process parameters are an elastic modulus of 2437.5723 MPa and a tensile strength of 46.5196 MPa. This optimal process increases the elastic modulus by 12.3152% while maintaining a high tensile strength. [ABSTRACT FROM AUTHOR]

This paper identifies physical properties of an interesterified palm‐based fat (EIEPO) that predict oil binding capacity (OBC). A 100% EIEPO sample, 50% EIEPO sample diluted with 50% soybean oil (SBO), and a 20% EIEPO sample diluted with 80% SBO were used to test how saturation level impacts OBC. All samples were crystallized using either a fast (6.4°C/min) or slow (0.1°C/min) cooling rate as well as with or without the application of high‐intensity ultrasound (HIU; 20 kHz) to generate a wide range of physical properties. Immediately after crystallization, the sample's physical properties, including crystal microstructure, solid fat content (SFC), viscoelasticity (G′, G″, and δ), melting behavior, hardness, and OBC (centrifuge method) were quantified. The samples were then stored for 48 h at 22 and 5°C and the aforementioned physical properties were measured again, with one additional measurement for the samples stored at 5°C—OBC using a filter paper method (OBCp). The results indicate that OBC can be optimized in a palm‐based fat by modifying the physical properties which was achieved via the processing conditions. Both measurements of OBC were significantly correlated with SFC, hardness, δ, and enthalpy. A model was developed to predict a sample's OBCc using the following dominant variables—SFC, hardness, peak temperature, enthalpy, and the number of crystals. These results suggest that OBC can be predicted using a sample's SFC, hardness, peak temperature, enthalpy, and number of crystals and that SFC, hardness, and enthalpy are main drivers of OBC. [ABSTRACT FROM AUTHOR]

This study evaluates the potential use of discarded plasterboard paper as fibers from buildings to reinforce concrete. Various concentrations of wastepaper fibers (0.5%, 1%, 1.5%, 2%, and 2.5% by weight of the binder) were investigated in this research. To mitigate the water absorption effect of the paper fibers, metakaolin was employed as a partial cement replacement. The results demonstrate that the inclusion of the wastepaper fiber enhances the mechanical and durability performance of the concrete. The optimal fiber proportion was identified as 1%, leading to a 29% increase in the compressive strength, a 38% increase in the splitting tensile strength, a 12% decrease in the water absorption, and a 23% decrease in the drying shrinkage with respect to the concrete containing 20% metakaolin. However, exceeding this optimal fiber content results in decreased mechanical and durability properties due to the fiber agglomeration and non-uniform fiber distribution within the concrete matrix. Based on the microstructural analysis, the improved performance of the concrete is ascribed to decreased porosity, more refined pore structure, and reduced propagation of microcracks within the concrete matrix in the presence of wastepaper fiber. According to the results, concrete containing 20% metakaolin and 1% wastepaper fiber exhibits durability and mechanical properties comparable to those of the traditional concrete. This finding highlights the significant promise of reducing dependency on conventional cement and incorporating suitable recycled materials, such as discarded plasterboard, and secondary by-products like metakaolin. Such a strategy encourages the preservation of resources, reduction in carbon dioxide emissions, and a decrease in the ecological footprint resulting from concrete production. [ABSTRACT FROM AUTHOR]

Digital twin, a core technology for intelligent manufacturing, has gained extensive research interest. The current research was mainly focused on digital twin based on design models representing ideal geometric features and behaviors at macroscopic scales, which is challenging to accurately represent accuracy and performance. However, a numerical representation is essential for precision microstructures whose accuracy and performance are difficult to measure. The concept of a digital twin for an accurate representation, proposed in 2015, is still in the conceptual stage without a clear construction method. Therefore, the goal of accurate representation has not been achieved. This paper defines the concept and connotation of an accuracy and performance-oriented accurate digital twin model and establishes its architecture in two levels: geometric and physical. First, a geometric digital twin model is constructed by the contact surfaces distributed error modeling and virtual assembly with nonuniform contact states. Then, based on this, a physical digital twin model is constructed by considering the linear and nonlinear response of the structural internal physical properties to the external environment and time to characterize the accuracy and performance variation. Finally, the models are evaluated. The method is validated on microtarget assembly. The estimated values of surface modeling, center offset, and stress prediction accuracy are 94.22%, 89.3%, and 83.27%. This paper provides a modeling methodology for the digital twin research to accurately represent accuracy and performance, which is critical for product quality improvements in intelligent manufacturing. Research results can be extended to larger-scale precision structures for performance prediction and optimization. [ABSTRACT FROM AUTHOR]

Bio-cemented soils can exhibit various types of microstructure depending on the relative position of the carbonate crystals with respect to the host granular skeleton. Different microstructures can have different effects on the mechanical and hydraulic responses of the material, hence it is important to develop the capacity to model these microstructures. The discrete element method (DEM) is a powerful numerical method for studying the mechanical behaviour of granular materials considering grain-scale features. This paper presents a toolbox that can be used to generate 3D DEM samples of bio-cemented soils with specific microstructures. It provides the flexibility of modelling bio-cemented soils with precipitates in the form of contact cementing, grain bridging and coating, and combinations of these distribution patterns. The algorithm is described in detail in this paper, and the impact of the precipitated carbonates on the soil microstructure is evaluated. The results indicate that carbonates precipitated in different distribution patterns affect the soil microstructure differently, suggesting the importance of modelling the microstructure of bio-cemented soils. [ABSTRACT FROM AUTHOR]

This article explores the properties of 2D defective Mo1.33C MXene, a material that shows promise in electromagnetic interference (EMI) shielding. The researchers tested a defect-containing Mo1.33C MXene "paper" and found positive results compared to other MXene and graphene-based materials. The article provides information on the preparation of the MXene and the experimental methods used for characterization and testing. The research suggests that Mo-based defective MXene could have applications in EMI shielding. [Extracted from the article]

The use of geopolymer as a cementitious material for geopolymer concrete (GPC) is beneficial for the sustainable development and green transformation of the construction industry. Geopolymer concrete has many advantages, such as high strength, heat and corrosion resistance, low hydration heat, and carbon emissions. This paper adopted the water–binder ratio, alkaline activator modulus, and slag replacement as the influencing factors, and used the 28-day compressive strength and flexural strength of geopolymer concrete as the response values to seek a reasonable mix design. In addition, through microstructure analysis, the mechanism of geopolymer on concrete was studied. The results indicated that as the water–binder ratio increased, the compressive strength first increased and then decreased, while the flexural strength continuously decreased. As the amount of slag replacement increased, the compressive strength and flexural strength would also increase. The effect of alkaline activator modulus on compressive strength and flexural strength was not significant. Through response surface methodology (RSM) analysis, the optimal design of geopolymer concrete was determined to have a water–cement ratio of 3.50, a modulus of 1.54 for alkaline activator solution, and a slag substitution rate of 47%. The microstructure analysis showed that the water–binder ratio and slag replacement improved the pore structure and density of concrete, thereby enhancing the macroscopic mechanical properties of concrete. This paper can provide a theoretical basis for the application of geopolymer concrete in engineering. [ABSTRACT FROM AUTHOR]

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This paper mainly explores the feasibility of using desert sand (DS) and recycled aggregate in cement-stabilized bases. Recycled coarse aggregate (RCA) and DS serve as the substitutes of natural coarse and fine aggregates, respectively, in cement-stabilized bases. A four-factor and four-level orthogonal test is designed to analyze the unconfined compressive strength, splitting tensile strength, and compressive resilient modulus. Furthermore, this paper investigates the effects of cement content, fly ash (FA) replacement rate, RCA replacement rate, and DS replacement rate on the road performance of cement-stabilized bases composed of RCA and DS. The test results reveal that the performance of cement-stabilized bases with partial RCA instead of natural coarse aggregate (NCA) and partial DS instead of natural fine aggregate satisfies the road use. The correlation and microscopic analyses of the test results imply the feasibility of applying DS and recycled aggregate to cement-stabilized bases. This paper calculates and evaluates the life cycle of carbon emissions of desert sand and recycled coarse aggregate cement-stabilized macadam (DRCSM) and finds that both DS and RCA can reduce the carbon emissions of CSM, which has a positive effect on improving the environment and solving the climate crisis. It is hoped that this paper can offer a solid theoretical foundation for promoting the application of DS and recycled aggregate in road engineering. [ABSTRACT FROM AUTHOR]

The aim of this research is to investigate the influence of nickel alloy type from the same group, the parameters of flame spraying, as well as the preparation of the substrate and the heat treatments of the substrate on the microstructure of the coating/substrate system. Due to the possibility of applying nickel alloys in corrective maintenance of tools used on elevated working temperatures, hot work tool steel X38CrMoV5-1 was selected as a substrate material. The investigation of the microstructure of the coating/substrate system was carried out according to the factorial design of experiment, where the input factors were varied on two levels. The factors that were varied are: Ni-based self-fluxing alloys - NiCrBSi and NiBSi; distance of the burner from the workpiece - small (6 mm) and large (20 mm); preparation of the substrate - roughened and non-roughened and the heat treatments of the substrate - soft annealed and tempered condition. Ni-based self-fluxing alloys were applied on samples (12,5 × 25 × 25 mm) by flame spraying with simultaneous fusing process. Analysis of the microstructures of the coating/substrate system was carried out on the Leica DM 2500M light microscope. After the conducted analysis the paper concluded that by spraying the selected coatings onto the X38CrMoV5-1 tool steel base, poor quality coatings are obtained, due to the appearance of cracks (NiCrBSi) or separation of the coating from the substrate (NiBSi). This is attributed to the formation of martensitic structure of the substrate after spraying and the presence of residual stresses. [ABSTRACT FROM AUTHOR]

Before artificial ageing, extruded aluminium profiles are subjected to stretching with a small cold deformation in the range of 0.5–2%. This deformation improves the geometrical stability of the extruded product and causes changes in the microstructure of the profile, which leads to the strain hardening of the material after artificial ageing. The work has resulted in the creation of the prototype of an original device, which is unique in the world, for the dynamic stretching of the extruded profiles after quenching. The semi-industrial unit is equipped with a hydraulic system for stretching and a pneumatic system for cold dynamic deformation. The aim of this research paper is to produce advantageous microstructural changes and increase the strength properties of the extruded material. The solution of the dynamic stretching of the profiles after extrusion is a great challenge and an innovation not yet practised. The paper presents the results of microstructural and mechanical investigations carried out on extruded AlMgSi(Cu) alloys quenched on the run-out table of the press, dynamically stretched under different conditions, and artificially aged for T5 temper. Different stretching conditions were applied: a static deformation of 0.5% at a speed of 0.02 m/s, and dynamic deformation of 0.25%, 0.5%, 1%, and 1.5% at speeds of 0.05 and 2 m/s. After the thermomechanical treatment of the profiles, microstructural observations were carried out using an optical microscope (OM) and a scanning electron microscope (SEM). A tensile test was also carried out on the specimens stretched under different conditions. In all the cases, the dynamically stretched profiles showed higher strength properties, especially those deformed at a higher speed of 2 m/s, where the increase in UTS was observed in the range of 7–18% compared to the classical (static) stretching. The microstructure of the dynamically stretched profiles is more homogeneous with a high proportion of fine dispersoids. [ABSTRACT FROM AUTHOR]

In this paper, we present an enhanced version of the two-scale numerical homogenization with application to asphalt concrete modeling in the elastic range. We modified the method of effective material parameters tensor assessment for analysis based on the representative volume element (RVE). As the method was tested on asphalt concrete, we also present two possible approaches to geometrical modeling of its internal microstructure. Selected numerical tests were performed to verify the proposed approach. The main novelties of this study, i.e. higher order approximation at the macroscale and modification of boundary conditions at the level of RVE analysis, improved the efficiency of our methodology by error reduction. Practically, we obtained a reduction of NDOF up to 3 orders of magnitude (comparing to full-scale and homogenized analysis) that was accompanied with the introduced error of order of several percent (measured in L2 norm). [ABSTRACT FROM AUTHOR]

This paper presents the influence of adding rinsed ilmenite mud waste (R-MUD) on the microstructure of Portland cement composites, compared to similar composites containing fly ash (FA). The aim of the study is the assessment of the pozzolanic activity of ilmenite mud waste by its impact on the microstructure of the cement matrix in comparison to the undoubted pozzolanic activity of fly ash. The presented test results include pore size distribution, phase composition, pozzolanic activity using thermal analysis, R3 bound water test, and microstructural analysis using scanning electron microscopy (SEM). Tests were performed on mortars cured for up to 360 days. The results presented in this paper have shown that R-MUD has a pozzolanic activity level similar to FA or better, which influences pore size distribution in the composite and its microstructure. During the curing process, the microstructure of composites containing R-MUD became more compact and sealed than those with FA, which might also increase their durability. The results of the R3 tests have proven the pozzolanic activity of R-MUD but its level was lower than FA. R-MUD might be a useful substitute for fly ash, especially given the lack of good-quality fly ash on the market. [ABSTRACT FROM AUTHOR]

The creep damage evolution of asphalt binder plays a significant role in investigating the formation mechanism of rutting. The rutting is the common distress at high temperatures for asphalt pavements. However, the reliability of existing creep damage parameters is under questioned, and these parameters cannot accurately illustrate the change of intrinsic microstructure for asphalt binder. In this paper, a new test protocol was given access to study the evolution of viscoelastic parameters during creep damage. It was completed by inserting the frequency sweep during creep test. The frequency sweep curve clusters were fitted by the generalized Kelvin-Voigt model for obtaining the change law of model parameters. Based on the change law and sensitivity analysis of model parameters, (E2 + E3)/2 was proposed as the creep damage variable. According to the curve of (E2 + E3)/2 versus loading time, two stages during the creep test could be identified: an approximate constant value in phase I and a linear decrease in phase II. Intrinsic differences about creep property of binders could be determined by this new proposed parameter. Above results not only ensure better understanding of the creep damage mechanism of binders, but also lay the theoretical foundation on predicting the anti-rutting performance of binders. [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]

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]

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]

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]

This research paper focuses on the fabrication of a microstructure based on a natural structure pattern of hydrophobic properties using micro-milling technology, followed by an investigation of the dimensional accuracy, roughness, and replication of the fabricated microstructure. Design, modeling (CAD system), fabrication, and replication are the steps of this process. Knowledge of biomimetics was used to select the microstructure. The main research aim of the experiments is to verify and extend the applicability of conventional CNC manufacturing technologies to obtain a functional surface structure. The micro-milling was carried out on a conventional DMG MORI CNC machine, a CMX 600 V three-axis horizontal milling center, using an external high-frequency electric spindle clamped to the machine. The machined material was aluminum alloy EN AW 7075. The tool was a 0.1 mm diameter double-edged ball mill made of sintered carbide and coated with TiSiN. The cutting conditions were determined according to the tool manufacturer's recommendations. To compare the achieved accuracies, the same microstructure was fabricated using PLA technology. For subsequent replication of the sample, the negative of the selected microstructure was created and machined. Subsequently, a positive microstructure was created using the silicone impression material by the replication process. This paper and the experiments performed extend the technical knowledge in the field of manufacturing surface functional structures and confirm the possibility of manufacturing the designed structures using chip and laser machining technology, with achieved discontinuities in the range of 3 to 50 μm. They also highlight the issues of replication of such structures with respect to critical manufacturing locations (geometrical parameters of the structures affecting the functional properties of the structure, venting, replica defects, etc.). [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]

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]

Arc spraying is one of the most effective and cost-efficient thermal spraying technologies for creating high-quality protective coatings. This paper examines the influence of arc spraying process parameters on the properties of steel coatings. The parameters varied in this study included gas pressure, wire feed rate, and the distance from the spray gun to the substrate (standoff distance). Experimental evaluations focused on surface roughness, thickness, porosity, structure, and hardness of the coatings. The techniques used for these evaluations included profilometry for roughness measurement, scanning electron microscopy (SEM) for structural analysis, Vickers hardness testing, and optical microscopy. The results demonstrate a significant influence of arc spraying parameters on the characteristics of the resulting coatings. The analysis revealed that the coatings produced under different modes exhibit a layered structure and vary in thickness. A detailed examination of the coating structure identified defects such as unmelted particles, voids, and delamination in the interface zone. The study of coating thickness and porosity showed that increasing the wire feed rate and decreasing the standoff distance leads to the formation of thicker and denser coatings. Specifically, increasing the wire feed rate from 2 to 12 cm/s resulted in a decrease in porosity from 12.59% to 4.33% and an increase in coating thickness to 699 μm. The surface analysis highlighted the importance of a comprehensive approach to selecting the optimal roughness. While increasing the wire feed rate up to 12 cm/s can increase the Ra roughness parameter, gas pressure also significantly influences this parameter, reducing roughness from Ra = 18.63 μm at 6 MPa to Ra = 15.95 μm at 8 MPa. Additionally, it was found that varying the arc spraying parameters affects the hardness of the coatings, with all modes resulting in hardness values higher than that of the substrate. Therefore, optimizing these parameters enables the achievement of the best combination of mechanical and structural properties in the coatings. These findings can be valuable for further improvement of arc spraying technologies and the expansion of their application across various industries. [ABSTRACT FROM AUTHOR]

This paper presents and demonstrates the development of a new lightweight coating for aluminum alloy from a novel multicomponent alloy based on the AlSiMgCu system. The coating was applied using a newly designed approach that combined high velocity oxy-fuel (HVOF) and plasma spraying processes. This hybrid technique enables the deposition of coatings with enhanced performance characteristics. The optical microscopy (OM) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM + EDS) revealed a strong adhesion and compaction between the multicomponent coating and the A6061 substrate. The new coating improved hardness by 50% and increased electrical conductivity by approximately 3.3 times compared to the as-cast alloy. Corrosion tests showed a lower corrosion rate, comparable to thermally treated A6061 alloy. Tribological tests indicated over 20% reduction in friction and over 50% reduction in wear rate. This suggests that multicomponent aluminum coatings could improve automotive and parts in contact with hydrogen by enhancing hydrogen fragilization resistance, corrosion resistance, electrical conductivity, and wear properties, with further optimization of thermal spraying potentially boosting performance even further. [ABSTRACT FROM AUTHOR]

17–7 PH stainless steel is a highly versatile material with a multitude of applications in a diverse range of fields, including aerospace, chemistry and petrochemistry, and medicine. The material's exceptional mechanical properties and corrosion resistance render it the optimal selection for numerous components and instruments. Nevertheless, the surface properties of 17–7 PH stainless steel are inadequate for applications requiring high hardness and wear resistance in certain extreme environments. Due to its excellent mechanical properties and corrosion resistance, it can be utilized in the manufacturing of pharmaceutical equipment components. However, certain specialized environments still require surface nitriding treatment. Considering the complex heat treatment process required for this material, this paper reports a detailed study of the surface performance changes of 17–7 PH steel before and after ion nitriding following aging heat treatment. The study employs rolled 17–7 PH stainless steel as the subject material. The impact of heat treatment on plasma nitriding of stainless steel is investigated by comparing and analyzing the influence of martensite content and dislocation density within the martensite of the material prior to and following heat treatment on the hardness, thickness, and corrosion resistance of the nitrided layer on the surface of the steel after nitriding. The results demonstrate that 17–7 PH stainless steel, which does not undergo heat treatment, exhibits a high internal dislocation density, a high nitriding efficiency, and consequently, a high surface hardness. Following the application of a heat treatment, there is an increase in the martensite content of 17–7 PH stainless steel, a decrease in the dislocation content, and an increase in the matrix hardness. [ABSTRACT FROM AUTHOR]

This paper introduces an innovative approach that enables the automated and precise prediction of steel's chemical composition based on the desired Jominy curve. The microstructure, and in fact the presence of martensite, is decisive for the hardness of the steel, so the study considered the occurrence of this phase at particular distances from the quenched end of the Jominy sample. Steels for quenching and tempering and case hardening were investigated. With the representative collected dataset of hardness values from the quenched end of the Jominy specimen, microstructure and chemical composition of steels, the complex regression model was made using supervised artificial neural networks. The balance between cost and required hardenability can be achieved through optimizing the chemical composition of steel. This model of designing steel with required hardenability can be of great benefit in the mechanical engineering and manufacturing industry. The model is verified experimentally. [ABSTRACT FROM AUTHOR]

Reliable microstructure characterization is essential for establishing process–microstructure–property links and effective quality control. Traditional manual microstructure analysis often struggles with objectivity, reproducibility, and scalability, particularly in complex materials. Machine learning methods offer a promising alternative but are hindered by the challenge of assigning an accurate and consistent ground truth, especially for complex microstructures. This paper introduces a methodology that uses correlative microscopy—combining light optical microscopy, scanning electron microscopy, and electron backscatter diffraction (EBSD)—to create objective, reproducible pixel-by-pixel annotations for ML training. In a semi-automated manner, EBSD-based annotations are employed to generate an objective ground truth mask for training a semantic segmentation model for quantifying simple light optical micrographs. The training masks are directly derived from raw EBSD data using modern deep learning methods. By using EBSD-based annotations, which incorporate crystallographic and misorientation data, the correctness and objectivity of the training mask creation can be assured. The final approach is capable of reproducibly and objectively differentiating bainite and martensite in optical micrographs of complex quenched steels. Through the reduction in the microstructural evaluation to light optical micrographs as the simplest and most widely used method, this way of quantifying microstructures is characterized by high efficiency as well as good scalability. [ABSTRACT FROM AUTHOR]

In this paper, the nucleation and growth of austenite are controlled through a two-step annealing process to achieve multi-scale distribution and content increase of retained austenite in low manganese series medium-Mn steel. Combining SEM, EBSD, AES, and other experimental equipment, the evolution rules of the microstructure, properties, and element distribution behavior of the test steel during the annealing process are studied. Compared with one-step annealing, the two-step annealing significantly broadens the size distribution range of retained austenite. In the first step, after annealing at a higher intercritical temperature (760 °C), the ferrite and the M/A island are obtained, completing the initial partition of Mn and the refinement of microstructures. During the second step of annealing (720 °C), the primary Mn-rich martensite region provides higher nucleation driving force and finer dispersed nucleation sites, promoting the nucleation and growth of reverse transformation austenite. At the same time, the metastable-retained austenite formed after the first step of annealing continues to grow through interface movement. Furthermore, a high proportion (23.4%) of retained austenite with multi-scale distribution is formed in the final microstructure, and the product of strength and elongation increased from 21.8 GPa·% by the one-step annealing process to 30.1 GPa·%. [ABSTRACT FROM AUTHOR]

The continuous retained-mandrel rolling process is a promising method for titanium tube production with high efficiency and a short process. The importance of mandrel as a deformation tool supporting the inner wall is crucial. This paper thoroughly examines the influence of mandrel velocity on the deformation characteristics at the groove vertex using three approaches: numerical simulation, shear-deformation observation experiments, and microstructure analysis. The following conclusions are drawn: Decreasing the mandrel velocity enhances the penetration of shear deformation into the inner wall of the titanium tube, improves thickness uniformity, and shifts the deformation mechanism near the inner wall from twinning to dislocation slip. As a result, the volume fraction of recrystallization increases from 18.4% to 42.3%. However, the mean shear strain increases first and then decreases to a certain value as the mandrel speed decreases, which is attributed to the combined influence of the cross-shear zone and the rolling force. [ABSTRACT FROM AUTHOR]

Laser powder bed fusion (LPBF) presents both opportunities and challenges with regard to the customisation of NiTi alloy properties. This paper presents a systematic study of the influence of process parameters on the superelasticity of LPBF Ni-rich Ni51.3Ti48.7 shape memory alloy. The findings demonstrate that NiTi alloys produced through disparate process parameters exhibit disparate phase transformation behaviours and microstructures, which in turn result in varying degrees of superelasticity. At an energy density of 166.7 to 233.3 J/mm3, LPBFed Ni-rich Ni51.3Ti48.7 is predominantly in the martensite phase at room temperature due to the high phase transition temperature caused by a large amount of Ni evaporation loss, and exhibits almost no superelasticity. At an energy density of 66.7 to 116.7 J/mm3, LPBFed Ni-rich Ni51.3Ti48.7 has less Ni evaporation loss and lower phase transition temperature. It is primarily austenite phase at room temperature, and contains nano-precipitated phases internally, thereby exhibiting excellent superelasticity. The recovery rate is in excess of 5.5% at the initial compression (up to 5.7%) and in excess of 5.0% following ten cycles (up to 5.3%). Furthermore, the lower the energy density, the smaller the stress–strain hysteresis of LPBFed Ni-rich Ni51.3Ti48.7, with a variation range of 1.8–3.9 mJ/mm3. [ABSTRACT FROM AUTHOR]

Alkali-activated slag cementitious (AASC) foamed concrete (FC) has presented challenges such as rapid setting time and poor working performance. The use of sodium citrate (Na3Cit) as a retarding agent can improve the workability and microstructure of AASC foamed concrete. The effects of the dosage, modulus of water glass (WG, the main component is Na2O·nSiO2), and retarding agent on the properties and structure of FC were studied in this paper. The results indicated that using a water binder ratio of 0.4, WG with a modulus of 1.2, and an additional amount of 15% and 0.5% of Na3Cit, the prepared FC had a flowability of 190 mm. Its initial and final setting times were 3.7 h and 35.3 h. Its 7 d and 28 d compressive strengths reached 1.1 MPa and 1.5 MPa, respectively. After hardening, the pore walls were dense and consistent in size, with few larger pores and nearly spherical shapes. The addition of Na3Cit resulted in the formation of calcium citrate, which adsorbed onto the slag surface. This hindered the initial dissolution of the slag, reduced the number of hydration products produced, and decreased the early strength. With increasing curing time, the slag in the FC mixture dissolved further. This led to the decomposition of a portion of calcium citrate and the release of Ca2+. The Ca2+ reacted with [Si(OH)4]4− and [Al(OH)4]−, creating more C-(A)-S-H gel. This gel filled the voids in the FC and repaired any defects on the pore walls. Ultimately, this process increased the compressive strength of the FC in the later stages. [ABSTRACT FROM AUTHOR]

In this paper, a forging tool of a new design is proposed, which allows to implement shear and alternating strain in the entire volume of the deformed billet with a smaller change in its initial dimensions. To confirm the effectiveness of the proposed new forging tool in obtaining billets and forgings of the plates and slabs type of the required quality, a laboratory experiment was conducted. During the laboratory experiment, the forging of billets made of the steel 45 was carried out in such forging tools as step-wedge dies of two different variants (proposed and previously known) and in step dies. Analysis of the shape change of billets and the evolution of the microstructure of steel after two deformation cycles showed that the use of the step-wedge dies with a wedge protrusion on the upper die and a wedge cavity on the lower die is more promising for forging billets and forgings of the plates and slabs type with a given level of mechanical properties, since it allows to obtain a fine-grained structure with a smaller change in the initial dimensions of the billet. [ABSTRACT FROM AUTHOR]

Over the past few decades, remarkable breakthroughs and progress have been achieved in ultrafast laser processing technology. Notably, the remarkable high-aspect-ratio processing capabilities of ultrafast lasers have garnered significant attention to meet the stringent performance and structural requirements of materials in specific applications. Consequently, high-aspect-ratio microstructure processing relying on nonlinear effects constitutes an indispensable aspect of this field. In the paper, we review the new features and physical mechanisms underlying ultrafast laser processing technology. It delves into the principles and research achievements of ultrafast laser-based high-aspect-ratio microstructure processing, with a particular emphasis on two pivotal technologies: filamentation processing and Bessel-like beam processing. Furthermore, the current challenges and future prospects for achieving both high precision and high aspect ratios simultaneously are discussed, aiming to provide insights and directions for the further advancement of high-aspect-ratio processing. [ABSTRACT FROM AUTHOR]

This paper presents the experimental results of a study evaluating the mechanical and fatigue performance of welded Fe-Mn-Si SMA. For the experimental study, welded and welded-and-heat-treated Fe-Mn-Si SMA specimens were fabricated, and fatigue tests were performed at various stress amplitudes. In addition, direct tensile tests and recovery stress tests were also performed to evaluate the material properties of Fe-Mn-Si SMAs. The elastic modulus, yield strength, and tensile strength of the welded specimens were reduced by 35.4%, 12.1%, and 8.6%, respectively, compared to the values of the non-welded specimens. On the other hand, the elastic modulus, yield strength, and tensile strength of the welded-and-heat-treated Fe-Mn-Si SMA specimens were increased by 18.6%, 4.9%, and 1.3%, respectively, compared to the values of the welded specimens. Both welded and welded-and-heat-treated Fe-Mn-Si SMAs failed at lower cycles than the conventional Fe-Mn-Si SMAs at the same stress amplitude. High-cycle fatigue failure, characterized by cycles exceeding 104, typically occurs at relatively low stress levels within the elastic region, whereas low-cycle fatigue failure, generally occurring within cycles below 104, involves high stress levels that encompass both elastic and plastic deformation. Regardless of the welding condition, the stress amplitude at which Fe-Mn-Si SMA transitions from high-cycle to low-cycle failure exceeded the yield strength. [ABSTRACT FROM AUTHOR]

With the rapid advancement of 3D-printing technology, additive manufacturing using FDM extrusion has emerged as a prominent method in manufacturing. However, it encounters certain limitations, notably in surface quality and dimensional accuracy. Addressing issues related to stability and surface roughness necessitates the integration of 3D-printing technology with traditional machining, a strategy known as the hybrid technique. This paper presents a study of the surface geometric parameters and microstructure of plastic parts produced by FDM. Sleeve-shaped samples were 3D-printed from polyethylene terephthalate glycol material using variable layer heights of 0.1 mm and 0.2 mm and then subjected to the turning process with PVD-coated DCMT11T304 turning inserts using variable cutting parameters. The cutting depth was constant at 0.82 mm. Surface roughness values were correlated with the cutting tool feed rate and the printing layer height applied. The selected specimen's microstructure was studied with a Zeiss EVO MA 15 scanning electron microscope. The roundness was measured with a Keyence VR-6200 3D optical profilometer. The research results confirmed that the additional application of turning, combined with a reduction in the feed rate (0.0506 mm/rev) and the height of the printed layer (0.1 mm), reduced the surface roughness of the sleeve (Ra = 1.94 μm) and increased its geometric accuracy. [ABSTRACT FROM AUTHOR]

Due to its exceptional mechanical and chemical properties at high temperatures, Inconel 718 is extensively utilized in industries such as aerospace, aviation, and marine. Investigating the flow behavior of Inconel 718 under high strain rates and high temperatures is vital for comprehending the dynamic characteristics of the material in manufacturing processes. This paper introduces a physics-based constitutive model that accounts for dislocation motion and its density evolution, capable of simulating the plastic behavior of Inconel 718 during large strain deformations caused by machining processes. Utilizing a microstructure-based flow stress model, the machinability of Inconel 718 in terms of cutting forces and temperatures is quantitatively predicted and compared with results from orthogonal cutting experiments. The model's predictive precision, with a margin of error between 5 and 8%, ensures reliable consistency and enhances our comprehension of the high-speed machining dynamics of Inconel 718 components. [ABSTRACT FROM AUTHOR]

In the realm of military and defence applications, exposure to radiation significantly challenges the performance and reliability of solder alloys and joints in electronic systems. This comprehensive review examines radiation-induced effects on solder alloys and solder joints in terms of microstructure and mechanical properties. In this paper, we evaluate the existing literature, including experimental studies and fundamental theory, to provide a comprehensive overview of the behavior of solder materials under radiation. A review of the literature highlights key mechanisms that contribute to radiation-induced changes in the microstructure, such as the formation of intermetallic compounds, grain growth, micro-voids and micro-cracks. Radiation is explored as a factor influencing solder alloy hardness, strength, fatigue and ductility. Moreover, the review addresses the challenges and limitations inherent in studying the effects of radiation on solder materials and offers recommendations for future research. It is crucial to understand radiation-induced effects on solder performance to design robust and radiation-resistant electronic systems. A review of radiation effects on solder materials and their applications in electronics serves as a valuable resource for researchers, engineers, and practitioners in that field. [ABSTRACT FROM AUTHOR]

This paper introduces non-destructive testing (NDT) techniques centered on measuring magnetic properties, offering insight into evaluating structural steels throughout aircraft production and service life. It highlights the method's utility in quality control of steel components, particularly in detecting variations in microstructure affecting mechanical properties. The NDT method correlates material structural state with magnetic properties, utilizing parameters such as coercive force, remanence, and hysteresis loop area. Developed instruments, like the MA-05 Magnetic Analyzer and KRM-Ts coercive force meter, enable precise measurements in both closed and open magnetic circuits. Applications range from assessing heat treatment quality to monitoring materials degradation in challenging conditions. A set of 12 gas containers that have been in service in aircraft for more than 40 years are tested as a case study, demonstrating the method's efficacy in evaluating damage accumulation. Future prospects include other potential applications in testing aircraft landing gear components. [ABSTRACT FROM AUTHOR]

Aluminium alloys are widely employed across numerous thanks to their superior combination of strength, lightweight characteristics and corrosion resistance. In recent years, Friction stir processing (FSP) has come up as a promising technique for machining aluminium alloys, enabling greater control over microstructural evolution and mechanical properties. This paper provides an in-depth exploration the impact of process parameters on the microstructure and mechanical properties of aluminium alloys processed by FSP. The study focuses on the systematic investigation of the influence of the principle process parameters, including rotational speed, machining speed and applied pressure, on the microstructure and resulting mechanical performance of FSP machined aluminium alloys. Furthermore, the mechanical properties of FSP treated aluminium alloys are measured by a comprehensive set of tests, including tensile tests, hardness measurements and fracture tests. The relationship between process parameters and the mechanical behaviour of the alloys is analysed in detail to identify the optimum conditions for achieving the desired properties. Findings show that process parameters plays a significant role in defining the microstructure and mechanical properties of alloys. [ABSTRACT FROM AUTHOR]