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.
