An automobile steel with density of 7.55 g/cm3 and composition consisting of Fe-1.5Al-2Mn-0.18C was successfully produced, exhibiting remarkable tensile strength of 897.7 MPa and ductility of 19.3%. This steel’s microstructural transformations and their contributions to strength were analyzed after undergoing coiling treatments at temperatures of 400°C, 500°C, and 600°C. Our findings reveal an inverse relationship between the coiling temperature and both the steel’s strength and the product of strength and elongation (PSE), whereas ductility shows a positive correlation with rising coiling temperatures. The primary factors accounting for these variations in strength across different coiling temperatures are phase transformation strengthening, grain refinement strengthening, dislocation strengthening, and precipitation strengthening, with phase transformation and dislocation strengthening being the most influential. Furthermore, the reduction in size and volume fraction of (Ti, V)C particles observed at lower coiling temperatures is attributed to differences in carbide ripening and nucleation processes. In conclusion, this optimized low Mn-Al alloy chemistry combined with a hot rolling process provided a novel method to produce the automobile with low density and acceptable mechanical properties.
Alum sludge (AS) is an inevitable by-product generated during water purification and wastewater treatment plant when aluminium salts are used during the coagulation process. The study primarily aimed at comprehensive review of the physical, chemical and microstructure properties of alum sludge, assessing its suitability to act as a pozzolanic material in cement as a partial replacement for ordinary cementitious materials. AS has been proven to have high amount of silicon dioxide (SiO2), iron oxide (Fe2O3) and aluminium oxide (Al2O3) from XRD analysis. Scanning Electron Microscopic (SEM) was conducted to fully understand the morphological structure of AS. Various analytical techniques are implemented to assess the pozzolanic potential of alum sludge. Comparative studies have highlighted the use of alum sludge in concrete which shows a favourable outcome in terms of the mechanical strength including compressive strength, flexural strength and durability. The findings in the present studies suggest that with a proper treatment and processing, alum sludge can be a viable and eco-friendly alternative to conventional pozzolanic materials. The future challenges of the process in the development of an effective alum sludge were discussed.
Coronary artery disease (CAD) remains a leading cause of mortality, driving advancements in bioresorbable stents (BRS). While 3D printing enables precise fabrication of such stents, surface roughness remains a critical factor influencing biocompatibility and vascular healing. This study investigates the effects of layer height, nozzle temperature, printing speed and flow rate on the surface roughness of 3D-printed polycaprolactone (PCL) BRS. A novel aspect of this work lies in the application of the ImageJ SurfCharJ plugin to quantify roughness metrics (Ra and Rq) from scanning electron microscopy (SEM) images, which is an approach rarely explored in polymer-based stent research. Statistical analyses using t-tests and ANOVA identified layer height and nozzle temperature as the most significant factors, with 0.2 mm layer height and lower nozzle temperatures yielding relatively smoother surfaces. These findings contribute to the optimisation of FDM printing parameters for enhanced surface quality in PCL-based BRS and support the broader adoption of image-based roughness quantification in biomedical additive manufacturing.
Electron backscattered diffraction is widely used for phase and orientation imaging of crystalline specimens. Despite the inherent complexity of diffraction images, current analysis methodologies typically focus on the position of Kikuchi bands or direct comparisons between experimental and simulated patterns. These approaches require prior knowledge of the phases to be analyzed, limiting their applicability in certain scenarios. This paper introduces an alternative methodology, crystallographic analysis of lattice metric, which extracts phase and orientation information directly from the registered diffraction pattern without requiring predefined standards. The paper outlines the methodology, discusses limitations, and demonstrates possible application in phase analysis, lattice parameter ratio mapping, and qualitative lattice distortion mapping.
Carboxymethyl cellulose (CMC) dissolved in water at concentrations between 1% and 5% is used successfully for cooling cast iron parts with a ferritic–pearlitic matrix. The moderate cooling rate of this medium allows the structural transformation of austenite into martensite without promoting excessive structural and thermal stresses that could compromise the integrity of treated components. The initial temperature of the cooling medium is a critical parameter for achieving proper heat treatment results. This paper investigates the weldability characteristics of the CMC solution at temperatures of 20°C, 30°C, 40°C, 50°C, and 60°C, as well as the corrosion behaviour at the same temperatures for ferritic–pearlitic nodular cast iron samples. The influence of temperature on surface properties, including water contact angle and corrosion resistance, was examined. Cyclic and linear voltammetry tests were performed, and SEM observations along with EDX analyses were conducted on nodular graphite cast iron samples corroded in a 2% CMC aqueous solution. No significant differences were observed in the wetting capacity of the carboxymethyl cellulose solution compared to water.
This review highlights the recent advancements in surface coatings that are crucial for fire retardancy and abrasion resistance. Developments in fire-retardant coatings have introduced formulations that enhance thermal stability and improve combustion resistance. Simultaneously, innovations in abrasive materials focus on durable, high-strength, and heat-resistant compositions suited to demanding industrial applications. These trends reveal a growing need for sustainable, high-performance alternatives to traditional materials. Geopolymers are emerging as a promising solution, environmental compatibility, and superior performance to deliver coatings that excel in both fire protection and wear resistance. This review consolidates findings across fire protection and abrasive applications, emphasizing the role of geopolymer technology in developing coatings that can withstand both fire and mechanical wear. Future directions include optimizing geopolymer formulations to further enhance their resilience, making them adaptable to varied high-demand applications.
Composite materials offer a versatile and customizable solution for various industries, allowing for innovative designs and improved performance. Magnesium-based composites offer a compelling combination of lightweight, high strength, and other desirable properties, making them valuable materials for a variety of applications. The present study is focused on the microstructural, mechanical and wear characterization of the magnesium based hybrid composites which are developed with different combinations of Al2O3 and B4C microparticulates through stir casting route. The microstructural study reveals the diversity in the particle phase distribution. Composite with 2% Al2O3 and 6% B4C have shown higher hardness (78.5 HV0.2 and 67.3 HV0.2, respectively) and yield strength (273 MPa and 219 MPa, respectively) as compared to the other compositions. Furthermore, pin on disc test was conducted on the developed composites to study the wear and friction behavior. Test results revealed that the composite with 2% Al2O3 and 6% B4C has better wear resistance due to its superior mechanical properties as compared to the other developed composites. The results demonstrated the positive role of reinforcements in the AZ91D alloy, which can be a promising material for manufacturing structures and components in the automotive sector.
Directly brazing titanium (Ti) alloy and copper (Cu) using silver (Ag) based filler alloy has been recognized to be of limited success owing to the embrittlement of intermetallic compounds (IMCs) presented at joint interface. In the current investigation, strong and reliable brazing of Ti-6Al-4V and Cu was achieved by using a niobium (Nb) diffusion barrier deposited on Ti-6Al-4V base material and Ag-Cu-Ti active braze. The Nb diffusion barrier effectively suppressed the interaction between Ag-Cu-Ti filler and Ti-6Al-4V base material, avoiding formation of brittle Ti-Cu IMCs. Joint consisting of Ti-Nb solid solution, unconsumed Nb interlayer, remnant Ag-based braze and small quantity of tiny Ti-Cu IMC particles was obtained via diffusion bonding at Ti- 6Al-4V/Nb interface and active brazing between Nb interlayer and Cu based material. Bonding strength exceeding the Cu base material property was achieved in the resultant joint, ascribed to elimination of continuous bulk brittle interfacial reaction products.
The current study delves into a detailed analysis and optimization of an autonomous mobile platform, meticulously designed to navigate, and operate within the complexities of rough and challenging terrains. This platform isn’t just an ordinary machinery; it’s equipped with a manipulator arm, strategically designed to facilitate smooth sample retrieval, even in the most rugged environments. The autonomous mobile platform is suitable even for remote and hostile terrain, inaccessible to most conventional means of exploration. With a robust design and advanced capabilities, it’s crafted to navigate through obstacles effortlessly, ensuring that no potential sample remains uncollected. But the autonomous mobile platform doesn’t stop there, as it’s further distinguished by the integration of communication technology, which elevates its functionality to a whole new level. Real-time data transmission is one of the defining features of the platform. It allows for the continuous flow of information between the platform and its operators, facilitating swift decision-making and seamless coordination. This real-time data transmission isn’t limited to basic telemetry but encompasses a wide range of sensor data, providing valuable insights into the surrounding environment and the platform’s status itself. But perhaps one of the most revolutionary aspects of this platform is its ability to stream live video feeds to its operators. The opportunity to witness the sample retrieval process unfold in real-time, from the comfort of a remote command center, can be one of the advantages offered by the autonomous mobile platform. This live video streaming feature isn’t just a luxury; it’s a gamechanger. It provides operators with a visual perspective that surpasses mere data points, enabling more informed decision-making and better situational awareness. Additionally, the manipulator arm of the platform isn’t just a passive tool; it’s a versatile asset that significantly extends its capabilities. With a range of motion and precision that rivals even the most skilled human operators, the manipulator arm ensures that samples can be retrieved from almost any location, regardless of accessibility or terrain. Whether it’s collecting geological samples from a steep slope or extracting soil samples from beneath the surface, the manipulator arm gets the job done with unmatched efficiency and precision.
Electron backscattered diffraction is widely used for phase and orientation imaging of crystalline specimens. Despite the inherent complexity of diffraction images, current analysis methodologies typically focus on the position of Kikuchi bands or direct comparisons between experimental and simulated patterns. These approaches require prior knowledge of the phases to be analyzed, limiting their applicability in certain scenarios. This paper introduces an alternative methodology, crystallographic analysis of lattice metric, which extracts phase and orientation information directly from the registered diffraction pattern without requiring predefined standards. The paper outlines the methodology, discusses limitations, and demonstrates possible application in phase analysis, lattice parameter ratio mapping, and qualitative lattice distortion mapping.
The paper describes an experimental study of thin layers obtained using the vibrating electrode method. Vibrating electrodes are used because they are effective for producing layers with high hardness and wear resistance. Before the depositions, the base material was polished with abrasive paper to remove any oxides and impurities. Furthermore, four electrodes made of Ti, TiC, WC, and stellite were used to deposit different layers on the surface of steel blades using an Elitron 22 installation. The tungsten electrode was used to improve mechanical properties, whereas the titanium electrode increased corrosion resistance. Both the substrate and the deposited layers have had their chemical composition, microstructure, and hardness analyzed. The substrate is made of mediumalloyed steel, which is commonly used to make plastic shredder blades. Following deposition, the samples were subjected to final heat treatments, including quenching and tempering. Furthermore, microhardness and microstructural analyses were conducted to assess the properties and surface morphology of the coatings.
This study qualitatively demonstrates the role of Ni addition on transient liquid phase (TLP) Sn-Ag-Ni solder alloy through multiple reflow cycles, focusing on the formation, stability, and transformation of intermetallic compounds (IMCs). The optimal incorporation of 0.3 wt.% nickel (Ni) into the Sn-Ag solder alloy promotes the formation of thermally stable, high-melting-point IMCs, enhancing the structural integrity of the solder joint. Phase diagram analysis using Thermo-Calc software qualitatively confirms the coexistence of Ag3Sn, Ag4Sn, and Ni3Sn4 with the (3-Sn phase, supporting their structural role in solder joint stability. Thermodynamic analysis shows that Ag3Sn IMC has the highest favorability for formation and stability at room temperature, while Ni3Sn4IMC enhances high-temperature performance. Differential Scanning Calorimetry (DSC) analysis qualitatively supports these findings, revealing two distinct melting peaks. The first peak relates to the eutectic melting temperature, while the second peak relates to the high melting temperature. The Sn-Ag-Ni solder alloy is more thermally stable than Sn-Ag. Heat flow data indicate enhanced phase transformations and improved thermal stability in Ni-containing solder alloy. This study provides a qualitative understanding of the addition of Ni and its effects on the IMC evolution, phase inter-reaction, and high-temperature reliability critical for optimizing lead-free solder alloys in electronic packaging applications.
This study investigates the development of a superhydrophobic coating on steel substrates using a factorial design method, focusing on its anti-corrosion applications. The coating formulation includes palm slag, stearic acid, expanded polystyrene (EPS), and titanium dioxide (TiO2), with the coating applied to metal substrates. The superhydrophobic properties were assessed through water contact angle measurements, achieving a high degree of water repellence. Surface roughness was analysed using a 3D profilometer, revealing hierarchical nanostructures that contribute to the coating's hydrophobicity. The optimized formulation demonstrated effective corrosion protection, making it suitable for various industrial applications. The use of factorial experimental design (FED) proved highly effective in identifying optimal levels for the coating components, enhancing its performance. This research offers valuable comprehension into the formulation and characterization of superhydrophobic coatings, with significant implications for their use in diverse environments.
The Al-Co alloys corrosion resistance of various Co compositions (0.5-5 at.% Co) at different sintering times (4 h, 8 h, 24 h, 48 h, and 72 h) for 25 degrees C in (1M) hydrochloric acid electrolyte was studied by employing the electrochemical impedance spectroscopy (EIS) and the tafel polarization. Raman technique was used to identify the surface film of aluminum and its alloys, and scanning electron microscope (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) was used to determine the microstructure of the materials. In comparison to undoped aluminum, the Al-5 at.% Co material sintered at forty-eight hours exhibited outstanding corrosion performance. Pitting is discernible in the microstructure of sintered materials, particularly within the Al9Co2 phase. This phase exhibits faster corrosion compared to other intermetallic compounds such as Al13Co4. In terms of crystal structure and chemical composition of the dopant, the Al-Co intermetallic compounds are classed as a function of their relative nobility.
To explore an alternative green metallization strategy for nonconductive plastics, a conductive polypyrrole (PPy) precoat was prepared by in-situ interfacial polymerization of pyrrole on printed circuit boards (PCBs) and the electrodeposition of Cu on PPy precoat was investigated using both voltage-controlled method and current-controlled method. A uniform PPy film was successfully obtained on the PCB surface through modifying the PCB wettability and optimizing the pyrrole solution. Electrochemical measurements showed that sufficient polarization was necessary for the electroreduction and growth of Cu crystals on the PPy precoat due to its high electrical resistance. The presence of through-holes adjacent to copper in PCB boards demonstrates that constantcurrent electroplating enables effective deposition of uniform, adherent copper layers on polypyrrole (PPy) - pretreated substrates, establishing a viable alternative to conventional electroless copper plating for through-hole metallization in PCB manufacturing.
This study examines the strength characteristics and microstructural evolution of welded joints in X10CrWMoVNb9-2 (P92) steel piping used for pressure-critical components in power generation systems. The research evaluates the effects of prolonged thermal exposure through 3,000 and 10,000 h annealing cycles at 650 degrees C. Microstructural analyses were conducted using scanning electron microscopy (SEM), while mechanical performance was assessed via tensile testing. The investigation identified a direct correlation between microstructural degradation and diminished mechanical performance, a critical factor for high-temperature applications. Strength reductions were attributed to progressive coagulation of M23C6 carbides and Laves phase precipitation. The comparative analysis quantified property changes between the as-received parent material and weld metal, establishing baseline-to-aged condition performance metrics. These findings underscore the importance of microstructural stability in maintaining the operational integrity of P92 steel components under prolonged thermal stress, particularly in ultra-supercritical power plant environments.
The rise in demand for self-compacting concrete (SCC) results in an associated rise in the use of primary components like cement and aggregate. Furthermore, environmental deterioration, climate change, and pollution are significant environmental concerns. The problem of environmental degradation caused by the disposal of industrial waste, particularly coal bottom ash (CBA) from thermal power plants, requires urgent attention. Given the significant shortage of essential materials like cement and aggregates, it is crucial to find alternative materials to replace cement. There is a pressing need for high-quality materials that can effectively substitute for cement and withstand high temperatures. A key challenge in improving the fire resistance of concrete at elevated temperatures is maintaining its compressive strength. This research seeks to explore the effects of substituting ground CBA for cement on the compressive strength and fire resistance of self-compacting concrete (SCC). Four SCC-CBA mixtures were created by replacing 0%, 10%, 20%, and 30% of the cement weight with ground CBA. Both CBA-SCC and control SCC specimens were subjected to elevated temperatures of 200, 400, 600, and 800 degrees C for one hour, and mass losses along with compressive strength reductions were assessed post-heating. The results indicate that the highest compressive strength for SCC is achieved with 10% ground CBA. All mixtures met the specified strength requirements in 28 days, with compressive strength values ranging from 30 MPa to 39 MPa. At 400 degrees C, the SCC with 10% ground CBA showed greater mass and strength degradation compared to the control samples.
The ab initio pseudopotential method relies on Density Functional Theory (DFT), utilizing the generalized gradient approximation (GGA) as outlined by Perdew-Burke-Ernzerhof (PBE). Implemented through the Siesta program, this method examines the structural and optical properties of the nickel-iron alloy (Fe-Ni) that crystallizes in the FeNi3 structure. This approach is highly regarded for its accuracy in predicting the crystal structure and properties of FeNi3. The computed structural parameters align closely with both theoretical and experimental data, confirming the reliability of these predictions. The lattice constants, calculated at zero pressure, match previously reported theoretical and experimental results. Furthermore, the computed properties, including the Band Structure, Total Density of States (DOS), and Partial Density of States (PDOS), and elastic constants values for the alloy, suggesting its suitability for specific applications in targeted fields.
Advanced packaging technologies, such as Intel's Embedded Multi-Die Interconnect Bridge and Foveros, have revolutionized semiconductor integration by enabling compact, high-performance devices through 3D stacked die configurations. This study focuses on the warpage effects in 3D stacked die configurations using copper-copper (Cu-Cu) hybrid bonding under thermal cyclic conditions, which are critical for ensuring semiconductor device reliability. The research employs ANSYS simulations through Thermal-Structural Coupling to analyze temperature distribution, thermal strain, and Von-Mises stress across different Cu-Cu hybrid bonding heights. Findings indicate uniform heat transfer across thermal cycles, with significant stress concentrations at corner bonding interfaces. Reducing Cu-Cu hybrid bonding height from 0.025 mm to 0.017 mm mitigates thermal strain and stress, with the 0.017 mm height proving optimal for minimizing warpage effects. This research provides insights crucial for enhancing semiconductor packaging reliability. It addresses industry demands for energy-efficient and compact electronic devices and supports industry standards, cost-efficiency, and innovation in semiconductor engineering.
The increasing demand for flexible, lightweight, compact, and cost-effective electronic products has led to a growing preference for Flexible Printed Circuit Boards over Rigid Printed Circuit Boards. However, thermal challenges during the reflow soldering process can significantly impact FPCBs. When exposed to elevated temperatures, Flexible Printed Circuit Boards are highly susceptible to deflection and thermal stress. This study examines the impact of temperature profile on FPCBs during the reflow soldering. Deformation measurements for both FPCBs and Rigid Printed Circuit Boards were obtained using a KEYENCE LK-G152 laser sensor installed at a reflow oven's entry and exit points. The experiment evaluated two temperature profiles, soaking and ramp profile, as variables. Findings revealed that FPCBs experienced greater deformation under the ramp profile, whereas RPCBs exhibited more deformation under the soaking profile. This research provides valuable insights for engineers and Printed Circuit Board designers, offering practical guidelines for optimizing mass production in the microelectronics industry.
