Fulltext search in archive

In order to reveal the action mechanism of different brass solder compositions on the microstructure of weld joints in unleaded-tin-coated coppers brazing-stitch welding, the laser welding process of solar panel busbar was studied by using three different coated brass solders: Sn-37Bi-3Ag, Sn-42Bi-3Ag and Sn-47Bi-3Ag. Scanning electron microscope, energy spectrometer, X-ray diffractometer, tensile testing machine and Vickers microhardness tester were used to test and analyze the influence of Bi element content on the microstructure and mechanical properties of weld joints in solar panel busbar brazing-stitch welding. The results show that: (1) With the increase of Bi element content, the wettability of soldering ceam is gradually improved, and the weld joints eutectic mainly consists of SnAg phase, Ag3Sn phase, Cu6Sn5 phase, Cu3Sn phase, SnAgCu phase, β-Sn sosoloid and Bi with rhombic layered structure. (2) The fracture of weld joints occurred at the interconnection belt side, it presents brittle and ductile mixed fracture. With the decrease of Bi element content, the tensile strength of weld joints gradually increased, and the maximum tensile strength of weld joints was 212 MPa. (3) The of weld joints decreases gradually from the busbar side to the interconnection belt side, and the highest microhardness of weld joints appears at the interface layer, it can reach 330.1 HV. With the decrease of Bi element content, the microhardness of weld joints gradually increased. This paper provides a scientific basis for the optimal selection and use of busbars in solar panels high-quality laser welding.

The effective application of additively manufactured materials requires accurate identification of their mechanical properties as well as damage mechanisms. Computer vision offers a novel approach for non-contact measurements, enabling the identification of selected mechanical properties. This paper presents a new method based on image analysis and the detection of circular markers for non-contact displacement measurements. The core principle involves detecting the centers of gravity of the circular markers formed on the sample under investigation. The centers of gravity are evaluated on each image created during the tensile test, representing nodal points. At these points, displacements are determined based on the non-contact extensometer. The deformations sought are a function of the displacements at each nodal point. These values were calculated based on several theoretical models, also used in the finite element analysis. The paper describes the computational procedure for determining the deformations based on the mentioned theoretical models. Subsequently, the total strain field is determined using linear interpolation of the displacement values at the individual nodal points. The results provided by each of the theoretical models were compared.

The article deals with sinterhardening process of lean Cr-Mo prealloyed steel for moderately loaded applications. New material Astaloy CrS with low alloying volume of chromium and molybdenum was analyzed as possible basis for sinterhardening process. Standard mechanical properties of frequently used and more expensive materials such as DistaloyDH and Astaloy CrM are chosen as a compara-tive criterion. Astaloy CrS+0.85%C samples with different compaction densities and Ni content were studied, mechanical properties and hardness after sinterhardening process were compared. The influ-ence of additional high-temperature sintering on mechanical properties was assessed. The micro-structure of the sinterhardening (SH) and high-temperature sintering + sinterhardening (HTS+SH) samples was studied quantitative analysis of the phase was given. As result, tensile strength greater than 900 MPa and hardness greater than 33 HRC can be obtained for investigated material.

Dynamic mechanical analysis (DMA) is an important method for evaluating the viscoelastic properties of polymeric materials, especially when investigating their mechanical response to various manufacturing parameters and surface treatments. In recent years, DMA analysis has been intensively used, among others, for the analysis of polylactide (PLA) produced by the fused filament fabrication (FFF) additive technology. The present study focuses on the effect of DCSBD plasma treatment on the dynamic-mechanical properties of PLA samples with different infill geometries (Line, Rectilinear and Concentric). In the study, experimental PLA samples were subjected to DMA analysis in the temperature range of 40 °C to 90 °C in order to analyze the changes in their viscoelastic properties after plasma discharge surface treatment. The results showed a decrease in the glass transition temperature (Tg) for all tested samples, while the extent of the decrease depended on the infill geometry used. The most significant changes were observed in samples with Rectilinear infill, which showed the best mechanical stability after plasma treatment. The study shows that plasma treatment can influence the mechanical properties of PLA products, opening new possibilities for optimizing their processing, reuse and application in technical areas requiring controlled mechanical response.

Titanium is the polymorphic metal whose recrystallization temperature significantly affects its final properties. The area between 850 °C and 995 °C is a very important area from the point of view of heat treatment of titanium alloys. It is a transition area just below the β transition limit. This article deals with the analysis of the influence of thermal loading on the change in tensile strength and fracture behavior of titanium alloys in comparison with thermally unloaded samples. Monitoring of fracture surfaces and description of the internal structure of the material.

In the automotive sector, poroelastic materials (PEMs) are used as trim elements to achieve the desired interior acoustics of a vehicle. This study examines the effect of manufacturing as well as measurement techniques on airflow resistivity. This property plays a key role in the acoustic behavior of PEMs. First, the importance of engineering acoustics and poroelastic materials in vehicle industry is reviewed, followed by the introduction of the most important properties and their measurement techniques. Next, the theory and the measurement techniques used to determine resistivity via direct method are detailed. Then the factors influencing the results and their quantified effects are presented. More than 10 influencing factors are identified and examined, from which the inhomogeneity, resulting from the production technology proved to be the most significant. The results obtained with direct and inverse methods are compared for validation purposes and to determine the achievable accuracy of the inverse method. The average difference between the two methods is 4.54%, which means that the inverse method can provide a good approximation. Finally, conclusions are drawn and suggestions are made for the future.

Article deals with analysis on influence of post-process settings profiles in the Polyworks software and its influence on measuring bias (difference between average surface profile deviation and artifact reference value) and standard deviation of measured data. The comparison was evaluated on glossy artifacts with freeform surfaces. Setting with least bias and standard deviation was than used to evaluate repeatability and systematic measurement error and minimum tolerance bandwidth Tmin according to VDA 5 and MSA 4, respectively for three conceptions of laser scanning technologies available on today’s market. Cartesian CMM LK Altera S with laser scanner Nikon LC15Dx (automated technology), Measuring arm Nikon MCAx S30 with laser scanner Nikon H120 (manual technology) and optically tracked handheld device Metronor M-Scan with laser scanner Nikon H120 (manual technology). The conclusions of the study can serve as a guide in technology selection for reverse engineering input data acquisition. Subsequently, the optimal parameters of the post-process settings (for glossy surfaces) in the Polyworks software are listed.

X-ray diffraction (XRD) is an analytical technique used to investigate the crystal structure properties of materials. However, the accuracy of XRD measurements can be significantly affected by the sam-ple's surface preparation. This study evaluates the impact of various surface preparation methods on the diffraction peak characteristics, phase composition, and residual stress analysis of two metallic materials: very low alloyed iron-based alloy labelled as pure iron and hardened 54SiCr6 steel. Various final steps of metalographic preparation of the surface for XRD were used, including mechanical grinding with coarse (P120) and fine (P1200) sandpapers, polishing with OPS colloidal silica, chemical etching in hot hydrochloric acid, and electrolytic etching. The results show that surface conditions influence more on the full width at half maximum (FWHM) than the intensity of diffraction peaks. Furthermore, the annealed pure iron sample (with low hardness) exhibited a more pronounced sensi-tivity to surface preparation compared to hardened 54SiCr6 steel, with its martensitic microstructure. Residual stress analysis using the sin²ψ method further revealed that mechanical grinding induces substantial compressive residual stress while polishing and etching methods produce nearly neutral or slightly tensile residual stresses. These findings highlight the importance of consistent and appropri-ate surface preparation methods for reliable XRD analysis.

Nowadays, increasing emphasis is placed on the production of parts using additive technologies, particularly for alloys that are difficult to process. In addition to standard additive technologies, such as Selective Laser Melting (SLM), other additive technologies are increasingly being used, including Directed Energy Deposition (DED). DED offers several advantages and is utilized both for producing entire components and for repairing damaged parts through weld cladding. In this study, the possibility of weld cladding of nickel-based hard alloys using DED was tested using a laser as the energy source to melt the additive material. The tests performed showed that selected nickel alloys, suitable for mould repair, are difficult to weld. Therefore, the experiments sought optimal process parameters and defined the accompanying technological operations in order to produce a crack-free weld cladding.

In this study, binary zinc-based alloys (Zn–1Mg, Zn–1Li, Zn–2Mn, wt.%) were synthesized by performing mechanical alloying (MA) of elemental powders, followed by consolidation using spark plasma sintering (SPS). The processing parameters were optimized to obtain homogeneous powders with controlled particle size. X-ray diffraction and SEM analyses confirmed the presence of secondary intermetallic phases (Mg2Zn11, Zn13Mn, ZnLi2 phases) formed during milling, which were preserved after SPS. Microstructural examination revealed a fine-grained microstructure with residual oxide networks originating from powder surfaces. Mechanical testing demonstrated significant strengthening effects after Mg and Li additions, with Zn–1Mg alloy reaching the highest hardness (128 HV1) and compressive strength (526.7 MPa), attributed to uniformly distributed Mg2Zn11 precipitates. However, this strengthening was accompanied by reduced ductility. Zn–1Li exhibited the most balanced combination of strength and plasticity, while Zn–2Mn provided only a limited improvement over pure zinc. These results confirm that mechanical alloying combined with SPS is a promising route for developing biodegradable Zn-based biomaterials with enhanced properties.

When diamond scribing knives are used to grind silicon wafers at ultra-high speeds, slight changes in the structure of the diamond scribing knives and changes in the grinding parameters will have a large impact on the processing accuracy and appearance of the silicon wafers. In order to reduce the defective rate of silicon wafers, improve the service life of diamond scribing knives and grinding efficiency. To address this issue, the working mechanism of the scribing knife grinding is analysed in the paper, the influence of spindle speed and feed rate on the quality of the silicon wafer slit when the scribing knife is grinding is studied, and the chipping of silicon wafers is observed through the scanning electron microscope and optical microscope, so as to analyse the shape of the cross-section, length of the cutting edge, concentration of diamond particles in the cutting edge, thickness of the cutting edge and determine the structure of the scribing knife, and to test its influence on the silicon wafer slit by means of the grinding experiments. The structure of the scribing knife was determined, and its influence on the quality of silicon wafer slit was tested by grinding experiment. The results show that the wear rate of diamond particles, slit quality and processing efficiency of the scribing knife are optimal when grinding silicon wafers at 50,000 r/min and 60-80 mm.sec^-1. The above study can help to further understand the wear mechanism of the scribing knife in the process of ultra-high-speed grinding of silicon wafers, improve the machining efficiency, and prolong the service life of the tool.

Today, considerable attention is paid to the production of solid castings (approx. 2000 kg) from cast iron with spheroidal graphite. The metallurgical preparation of large quantities of melt is very difficult. This difficulty is related not only to the melting and preparation of large quantities of melt, but above all to its metallurgical treatment - inoculation and modification. Melt modification ensures the production of cast iron with spheroidal graphite. Material castings, such as machine tool components, cannot be destroyed to determine the quality of the cast iron produced. Therefore, this paper outlines a methodology to proceed in determining the quality of manufactured castings. It is possible to observe the chemical composition of cast iron, thermal analysis of cast iron using liquidus temperature value, subcooling temperature, eutectic recalescence, primary solidification recalescence, eutectic solidification time. Furthermore, to observe the mechanical values of cast iron (yield strength, ultimate strength and ductility) on fabricated bars of overmolded Y blocks or to observe the micro-structure of cast iron on microscope.

The aim of this study is to investigate the effect of oscillatory loading frequency on the dynamic-mechanical properties of 3D printed thermoplastics, namely acrylonitrile-butadiene-styrene (ABS), glycol-modified polyethylene terephthalate (PETG), and polylactide, also known as polylactic acid (PLA). The investigated samples were manufactured using fused filament fabrication (FFF) technology and tested at different oscillation frequencies (1, 5, 10, 15 and 20 Hz). Dynamic mechanical analysis (DMA) demonstrated that an increase in the oscillation frequency causes an increase in the glass transition temperature (Tg) for all analyzed materials, while in the case of the used loading frequencies above 5 Hz, an almost linear dependence between the magnitude of the applied frequency and Tg was observed. The findings also show that with increasing frequency of mechanical loading, there are changes in the visco-elastic properties of the investigated polymers, specifically in the value of the storage modulus (E′), loss modulus (E′′) and loss angle (tan δ), which points to the complex behavior of the materials under dynamic conditions. The results of this study provide valuable insights for the use of 3D printed polymer materials in applications where they are exposed to dynamic stress - in the automotive or aerospace industries.

Five-axis machine tools are key equipment to process impellers, blades, and other precision mechanical parts. However, the accuracy of the machine tools is significantly influenced by assembly errors, and over time, these errors may change, further impacting the machining accuracy. Traditional laser interferometry technology can identify such assembly errors. The development of on-machine measurement technology has enabled methods that utilize on-machine measurement for assembly error calibration, improving calibration efficiency. The study introduces an efficient method to calibrate the assembly errors of machine tool rotary axes. First, the kinematic model for a machine tool is develop. Subsequently, utilizing on-machine measurement technology, the assembly errors of the rotary axes are calibrated, and the calibration uncertainty is analyzed. The results of the experiment confirm the validity of the calibration method. This method can be applied for periodic calibration of machine tool assembly errors, continuous monitoring variations in machine tool accuracy and ensuring the stability of machining quality.

Biodegradable zinc-based alloys have recently attracted attention as promising candidates for temporary implant applications due to their favourable corrosion behaviour and biocompatibility. In this study, three materials — pure Zn, Zn–1Mg alloy, and a Zn + Zn–1Mg composite — were fabricated via powder metallurgy and extrusion to evaluate their microstructural characteristics and tensile performance. The composite material was designed to combine ductile Zn regions with a reinforcing Zn–1Mg network, aiming to achieve a balance of strength and ductility. Microstructural analysis revealed coarse-grained Zn regions surrounded by ultrafine-grained Zn–1Mg areas containing Mg₂Zn₁₁ particles, with oxide shells present at the Zn/Zn–1Mg interfaces. Tensile testing showed improvement in mechanical performance compared to the individual constituents. However, the oxide shells prevented effective load transfer between the fine-grained and coarse-grained areas of the microstructure.

In a vertical impact crusher, material particles undergo multiple impact collisions and eventually break due to accumulated damage. In order to further study the crushing mechanism of the crusher, a cumulative damage model of material particles under re-peated impact was established. Firstly, a crushing model is established based on the specific fracture energy, reflecting material particles' cumulative damage and crushing process. Then, the simulation model of the crushing system of the vertical shaft impact crusher is established. And by simulating the crushing process of limestone particles in a crusher, it reveals that the crushing of particles is essentially due to the crushing that occurs as a result of multiple cumulative impacts. Next, the simulation model is used to simulate and analyze the rotor's power and particle size distribution of crushed products of limestone, iron ore, and copper ore during crushing. The reliability of the simulation model is experimentally validated. Finally, the simulation analyzed the in-fluence of the diameter and speed of the crusher rotor, as well as the mixed feeding of various materials, on the rotor power and material crushing effect. The results show that the particle size distribution curves of three types of crushed products, including limestone, have a high degree of agreement between simulation and experiment. Fur-thermore, the simulation values of rotor power and specific power consumption fit well with the experimental values, verifying the reliability of the simulation model. As the rotor diameter and rotor speed increase, the rotor power and sand production rate gradually increase. And the increase in rotor power is much greater than the increase in sand production rate. When the feed is a mixture of multiple materials, the rotor power increases approximately linearly with the increase of the proportion of high hardness materials in the feed, while the yield of fine particles in the crushed product decreases with the increase of the proportion of high hardness materials in the feed.

This study used JMatPro software to comprehensively analyze the new low-iron-loss cold-rolled non-oriented high-grade electrical steel 35W210X, calculating phase composition, Gibbs free energy, stress-strain relationships, and yield strength changes. Results showed its ferritic structure and consistent calculated room-temperature yield strength with experiments. To study production cracks, JMatPro data was used in Deform-3D to simulate the five-pass reciprocating cold rolling on a Sendzimir 20-roll mill, successfully replicating the cracks. Aiming at the problems of frequent cracking and low yield rate (<50%), the study found the original single normalizing annealing process inadequate. Thus, an optimized double annealing process was adopted, controlling cracks and raising the yield rate to over 85%. This research offers theoretical and technological support for rolling high-silicon electrical steels like 35W210X.

The Ti-6Al-4V alloy is widely used as a material for medical implants. In the future, it may be employed for 3D printing using the selective laser melting method. The advantages of 3D printing are for example production of complex shapes or ability to create customized implants. One of the disadvantages of this method is the deterioration of mechanical properties, particularly the ductility of the alloy, caused by high residual stress resulting from rapid cooling during printing. This article aims to characterize the microstructure and defects of the printed alloy and the impact of hot isostatic pressing. Optical microscopy, scanning electron microscopy, and micro-computed tomography were utilized for the study. It was found that the heat treatment has a significant effect on the pore size and microstructural transformation. These findings could lead to the optimization of the manufacturing process and improve the quality of implants made from this alloy.

longitudinal externally splined parts have garnered increasing attention due to their critical role in power transmission across various industrial applications. This study explores the use of the internally rotating ballizing technique for manufacturing these components. The process was analyzed both experimentally and numerically through a mathematical model. The experimental investigation focused on key process parameters, including die rotational speed (50, 63, 80, 100, 125, 160, 200, 250, and 315 rpm), axial feed rate (0.13, 0.15, 0.18, and 0.21 mm/rev), interference between the balls and the tubular sample (cross in-feed: 2.5, 3.5, 4.5 and 5.5 mm), and initial tube thickness (4, 5, 6 and 7 mm). The study assessed the influence of these variables on the forming load and the quality of the produced longitudinal externally splined sleeves. A numerical model was developed to predict forming loads, and the findings indicated that these parameters significantly affect both (forming load and filling ratio). The optimal values for these variables were identified, and the numerical results showed a strong correlation with experimental findings. Keywords: Externally Splined Sleeves, rotary Ballizing Process, Numerical method, Experimental Study and forming load.

The materials used in VVER nuclear power plants are subject to thermal ageing in operation, among other degradation mechanisms. The aim of the experiment was to verify the effect of thermal ageing on the change of ultrasound velocity on the extracted parts of main circulation piping and pressurizer surge line made of austenitic steels. Two steel conditions were evaluated, as received and thermally aged. The research was carried out on samples made from non-operated pipelines and samples from pipelines after 28 years of operation. The samples were subjected to thermal ageing at 450 °C in an atmospheric furnace with a specified exposure time to simulate extended operation of the compo-nent for 60 years, where 1 year of operation means 10 months at 100 %-unit power and 2 months in shutdown. The samples were subjected to ultrasonic property measurements and the longitudinal and transverse wave velocities obtained are further used to calculate the Poisson's constant and elastic modulus E of the material. To verify the ultrasonic measurements, the samples were also subjected to mechanical tests to verify the changes in the mechanical properties in terms of elastic behaviour of the selected steels when subjected to a static 3-point flexural test and Electron backscatter diffraction analysis (EBSD).

To enhance the accuracy of fault diagnosis (FD) in motor rotor systems, this study introduces a novel method that leverages feature extraction (FE) combined with a CNN-BiGRU-Attention deep learning model. Initially, the time-domain features of the vibration signals are extracted using Variational Mode Decomposition (VMD), which also effectively denoises the data. Subsequently, the frequency-domain features of the vibration signals are extracted via Fast Fourier Transform (FFT). The aggregated features are then fed into the CNN-BiGRU-Attention model to perform fault classification. In this model, the Convolutional Neural Network (CNN) module extracts local spatial features, the Bidirectional Gated Recurrent Unit (BiGRU) module models the temporal dependencies, and the Attention mechanism enhances the focus on critical fault information, thereby improving the model's classification performance. Experimental results demonstrate that the proposed FD method achieves an accuracy of 99.58%. Compared to other commonly used models, the performance metrics of our model show significant advantages and superior performance.

The given paper deals with the defects propagation in car tires for passenger vehicles under dynamic loading. The occurrence of defects has the significant influence on the lifetime and quality of the tire, especially during its operation as a part of the vehicle. The given defects are closely connected with a safety in road traffic. The aim of the study was to carry out a non-destructive analysis of the car tire for the purpose to analyze the defects propagation as well as to introduce the defects classification and their location along with the whole course of rupture as a result of increasing speed, loading and the number of hours or kilometers driven. During the analysis, we used a non-destructive method for detecting defects using a non-destructive analyzer that works on the principle of shearography. The experimental measurement was carried out for 12 car tires. The measurement results are displayed from the non-destructive analyzer in the form of protocols from measurement and video display. The evaluation of the results of the measurement for the propagation of defects is displayed graphically. In relation to the tire casing, the analysis of the defects propagation can help design engineers to solve critical issues by choosing the right material, modifying dimensions of individual components or even by redesigning the overall construction of the tire casing and thus to increase the safety from the as-pect of vehicle operation.

The present paper is focused on the study of the characteristics of selected titanium alloys before and after heat treatment. The specimens were cooled both in water and liquid nitrogen from 900°C and 1000°C for pure titanium and from 1000°C and 1100°C for the Ti-6Al-4V alloy. Further, the paper deals with line MG63 live bone cells deposited on a titanium base substrate. Proliferation and differentiation are monitored of cells during 7-day in vitro cultivation portraying growth of cells on a biologically selected material.

The thesis deals with the surface treatments of bearing steel processed for wind turbines, on which the quality parameters of the surface treatments performed were compared. This is blackening, which is a method of surface treatment that allows the protection of the base material from the negative effects of external influences, in particular from moisture and associated corrosion. The application of surface treatment by blackening contributes to a better and more efficient start-up of the bearing in service. In the experimental part, the individual results of the structural analysis carried out for all types of materials investigated are evaluated, with the analysis focusing on the structural properties, the quality of the adhesion properties and the influence on the service life of the machine components. Electron microscopy was used to investigate the structural properties of the layer as well as the base material, which allowed to obtain the necessary data to meet the objectives of this work.

The CuZn10 alloy, a prominent brass variant known for its excellent cold formability, corrosion resistance, and suitability for various cold forming processes such as bending and stamping, finds widespread application across numerous industries. Optimizing its performance for specific industrial demands necessitates a thorough understanding of how different preparation technologies influence its intrinsic properties. This study provides a comprehensive examination into the impact of various processing routes on both the structural evolution and mechanical characteristics of deep-drawing CuZn10 brass. Utilizing advanced analytical techniques, including Electron Backscatter Diffraction (EBSD) analysis, the research systematically investigates microstructural changes, grain orientation, and texture development resulting from distinct manufacturing processes. The findings delineate clear correlations between specific preparation methodologies and the resulting mechanical properties, such as hardness, strength, and ductility. This work aims to establish a foundational understanding that can guide industrial practitioners in selecting optimal processing technologies to tailor CuZn10 alloy for enhanced performance and efficiency in its diverse applications. The insights gained are critical for refining manufacturing protocols and improving material quality in an industrial context.

Core-shell powders have been extensively studied due to their complex structure and wide range of applications. W@Ag core-shell powders are particularly interesting due to the synergy between the tungsten and silver, which can be beneficial in the electronics industry. However, knowledge of their thermal stability is limited, particularly concerning the impact of annealing temperatures on structural integrity and oxidation resistance. In this work, W@Ag core-shell powder was heat-treated in the temperature range 100–700 °C for 1 h in air. Investigation of the microstructural changes using scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy showed that the limiting temperature is 500 °C, when the shell began to decompose and the core began to oxidize. Moreover, X-ray diffraction analysis determined that the phase composition of the thus heat-treated material consisted of approxi-mately 50 % Ag and 50 % Ag2WO4.

Hollow TiO₂ architectures are attractive for catalysis and sensing but typically produced by wet-chemical templating and sub-micron sizes. Here we demonstrate a dry, template-free route to nanoscale hollow shells by combining DC magnetron sputtering with in situ TEM heating. Heating to 900 °C produces sub-50 nm TiO₂ hollow shells with ~20 nm compact walls via oxidation-driven Kirkendall hollowing. The oxide evolves from amorphous at low temperature to anatase locally (~500 °C) and then to a rutile/brookite mixture by ~600 °C. The hollow architecture withstands a temperature of 900 °C without measurable sintering. Beam-off regions and ex-situ air annealing show the same hollowing and phase evolution, confirming a thermally driven, not beam-induced, transformation reproducible in air.

The introduced work deals with the microscopic analysis of metallographically prepared selected metal materials structures, using a scanning electron microscope (SEM). Prepared samples of seamless steel pipes were subjected to a thorough microscopic examination from the outer surface to the inner regions in order to interpret the spe-cific structure, including the change of the inner surfaces due to wear. The experiment showed that the micro-structure and character of the surfaces play a crucial role in the behavior of metallic materials under real condi-tions. Four types of pipes were monitored according to their use. The unused steel pipe (designated as sample No. 1) exhibited a rough outer surface with identified inclusions, while the used pipe (designated as sample No. 2) showed marks of intergranular corrosion and significant wear after long-term use. The older pipe (designated as sample No. 3) showed a decarburized area and inclusions containing sulfides and aluminum. The steel pipe with corrosion layers (designated as sample No. 4) exhibited a continuous corrosion layer with cavitation and cracks. The results of this study offer a comprehensive view relating to the influence of the nature of the micro-structure and wear on the water flow (performance) of metal pipes, with an emphasis on the identification of possible risks associated with geometry change, corrosion and wear. The recommendations create a basis for predicting the degradation as well as appropriate maintenance to ensure their long and reliable service life under real-world conditions of use.

Cast iron with nodular graphite is one of the most important structural materials that exhibit really good mechanical properties already in the as-cast condition. Nowadays, cast iron with nodular graphite is used in many areas of the manufacturing industry, the most widespread being in the engineering and automotive industries. The applicability of this material for construction purposes is mainly due to its mechanical properties, which are close to those of steel, but the production cost of cast iron is lower. This experiment was aimed at optimizing the production of ductile iron castings in the casting pits so that the foundry could produce ductile iron castings in the casting pits. Therefore, the optimization of the moulding compound database material was carried out in numerical simulation and at the same time, the heat transfer measurement of the foundry sand mould was carried out.

Fused silica is a key material for high-precision applications such as micro-optics and microfluidics. One route to improving direct laser writing (DLW) of fused silica is the use of shorter laser wavelengths, which enable tighter focusing and enhanced absorption. In this study, the influence of process parameters on surface quality and material removal during DLW using a deep ultraviolet (DUV) ultrafast laser (257 nm, 1 ps) was investigated. A full-factorial design of the experiment was used to identify conditions that optimise both surface quality and ablation efficiency. Surface roughness as low as Sa ≈ 200 nm and material removal rates up to 0.048 mm³∙min-1 were achieved. Conditions that led to surface degradation were also identified. Finally, the optimised parameters were applied to fabricate a microfluidic demonstrator. These results confirm that DUV ultrafast DLW is a powerful technique for fabricating high-fidelity features in fused silica with exceptional precision and quality that can be used for micro-optics or microfluidics devices.