The simulation of spinodal decomposition in Zr-Nb-Ti alloys, executed using the Cahn-Hilliard equation-based phase field method, investigated the effects of varying titanium concentrations and aging temperatures (800-925 K) on the microstructure after 1000 minutes. Following aging at 900 K, the Zr-40Nb-20Ti, Zr-40Nb-25Ti, and Zr-33Nb-29Ti alloys displayed spinodal decomposition, resulting in the formation of two distinct phase formations: Ti-rich and Ti-poor phases. At 900 K, the early aging of Zr-40Nb-20Ti, Zr-40Nb-25Ti, and Zr-33Nb-29Ti alloys resulted in spinodal phases taking on respective morphologies: a network-like, interconnected, non-oriented maze shape; an independent, droplet-like appearance; and a grouped, sheet-like structure. An escalation in the Ti concentration within Zr-Nb-Ti alloys corresponded to an enlargement in the modulation wavelength, yet a reduction in amplitude. The temperature at which the Zr-Nb-Ti alloy system aged had a considerable effect on the spinodal decomposition process. In the Zr-40Nb-25Ti alloy sample, the Zr-rich phase's shape transitioned, with increasing aging temperature, from an intricate, interconnected, non-oriented maze to a discrete, droplet-like configuration. This transformation was accompanied by a quick increase in the wavelength of concentration modulation, which then stabilized, but the modulation amplitude decreased. The Zr-40Nb-25Ti alloy exhibited no spinodal decomposition as the aging temperature reached 925 Kelvin.
From Brassicaceae sources including broccoli, cabbage, black radish, rapeseed, and cauliflower, glucosinolates-rich extracts were produced using an eco-friendly microwave-assisted method with 70% ethanol, followed by assessments of their antioxidant activity in vitro and their influence on steel corrosion. All extracts demonstrated good antioxidant activity, as evidenced by the DPPH and Folin-Ciocalteu assays, with a DPPH remaining percentage of 954-2203% and a total phenolic content of 1008-1713 mg GAE/liter. The electrochemical measurements, conducted in a 0.5 M H₂SO₄ solution, showed the extracts to be mixed-type inhibitors, indicating their ability to inhibit corrosion in a concentration-dependent fashion. Concentrated extracts of broccoli, cauliflower, and black radish demonstrated a significant inhibition efficiency, ranging from 92.05% to 98.33%. Experiments on weight loss demonstrated a decline in inhibition efficiency as temperature and exposure time rose. Analyses of the apparent activation energies, enthalpies, and entropies of the dissolution process led to the determination and discussion of the inhibition mechanism. The SEM/EDX analysis of the surface demonstrates that the compounds derived from the extracts adhere to the steel surface, forming a protective coating. Concerning the bond formation between functional groups and the steel substrate, the FT-IR spectra offer confirmation.
The paper examines the consequences of localized blast loading on thick steel plates via experimental and numerical investigations. A localized trinitrotoluene (TNT) explosion was performed on three steel plates, each 17 mm thick, and the damaged areas were subsequently examined using a scanning electron microscope (SEM). The steel plate's damage response was simulated employing ANSYS LS-DYNA software. The interplay between empirical results and numerical simulations yielded insights into TNT's impact on steel plates, unveiling the damage patterns, confirming the accuracy of the numerical model, and establishing criteria for identifying the different types of steel plate damage. A dynamic relationship exists between the explosive charge and the steel plate's damage mode. A major factor in determining the diameter of the crater on the steel plate is the diameter of the contact area between the explosive material and the steel plate. In the steel plate, the generation of cracks follows a quasi-cleavage fracture pattern, while the formation of craters and perforations is indicative of a ductile fracture process. The ways steel plates are damaged can be categorized into three types. The numerical simulation, despite some minor discrepancies in its results, maintains high reliability, making it a helpful auxiliary tool in conjunction with experimental efforts. To predict the failure type of steel plates during contact explosions, a novel criterion is proposed.
Nuclear fission's hazardous byproducts, cesium (Cs) and strontium (Sr) radionuclides, can unintentionally find their way into wastewater systems. A batch-mode experiment investigated the adsorption capacity of thermally treated natural zeolite (NZ) sourced from Macicasu, Romania, in removing Cs+ and Sr2+ ions from aqueous solutions. Varied amounts (0.5 g, 1 g, and 2 g) of zeolite samples with particle sizes categorized as 0.5-1.25 mm (NZ1) and 0.1-0.5 mm (NZ2) were contacted with 50 mL of working solutions containing Cs+ and Sr2+ ions, at initial concentrations of 10, 50, and 100 mg/L, respectively, for a period of 180 minutes. The concentration of Cs in aqueous solutions was quantitatively assessed using inductively coupled plasma mass spectrometry (ICP-MS), while the strontium (Sr) concentration was determined via inductively coupled plasma optical emission spectrometry (ICP-OES). The removal effectiveness of Cs+, varying between 628% and 993%, differed from that of Sr2+, whose effectiveness ranged between 513% and 945%, dictated by the initial concentrations, time of contact, the mass of the adsorbent, and its particle size. The sorption behavior of Cs+ and Sr2+ was evaluated through the application of nonlinear Langmuir and Freundlich isotherms, as well as pseudo-first-order and pseudo-second-order kinetic models. The PSO kinetic model adequately described the sorption kinetics of cesium and strontium ions on thermally treated natural zeolite, according to the results. Strong coordinate bonds with the aluminosilicate zeolite framework are crucial for the chemisorption-driven retention of both Cs+ and Sr2+.
This study details metallographic investigations and tensile, impact, and fatigue crack growth tests performed on 17H1S main gas pipeline steel, both in its initial condition and following extended service. A considerable number of non-metallic inclusions, forming chains, were discerned within the LTO steel's microstructure, oriented along the direction of pipe rolling. For the steel, the lowest measured elongation at break and impact toughness were observed near the pipe's inner surface, specifically in the lower part of the pipe. FCG testing under a low stress ratio (R = 0.1) of 17H1S steel, both degraded and in the AR state, produced no discernible change in growth rate. When subjected to a stress ratio of R = 0.5, the tests demonstrated a more significant degradation effect. For the LTO steel situated in the lower internal pipe area, the Paris law region on the da/dN-K diagram was greater than the corresponding values for the AR-state steel and the LTO steel located in the pipe's upper region. Numerous delaminations of non-metallic inclusions from the matrix were identified via fractographic techniques. Their involvement in the brittleness of steel, particularly steel found near the inner surface of the lower pipe section, was observed.
The purpose of this research was to design and develop a new bainitic steel with a focus on high refinement (nano- or submicron scale) and superior thermal stability at elevated operating temperatures. Protein Biochemistry Improved thermal stability, a measure of in-use performance, was observed in the material, contrasting with the limited carbide precipitation in nanocrystalline bainitic steels. To determine the expected low martensite start temperature, bainitic hardenability, and thermal stability, specific criteria are set forth. The methodology behind the novel steel's design, coupled with a detailed analysis of its properties, including continuous cooling transformation and time-temperature-transformation diagrams, is elucidated through dilatometry. In addition, the influence of bainite transformation temperature was also examined in relation to the level of structural refinement and the size of austenite blocks. Lapatinib cost It was examined if a nanoscale bainitic structure could be realized in medium-carbon steel samples. Ultimately, the implemented approach for upgrading thermal stability under elevated temperatures was evaluated in depth.
Medical surgical implants benefit greatly from the high specific strength and good biological compatibility properties of Ti6Al4V titanium alloys. The human environment presents a challenge to Ti6Al4V titanium alloys, inducing corrosion that reduces implant service life and can have adverse effects on human health. The application of hollow cathode plasma source nitriding (HCPSN) in this study led to the formation of nitrided surface layers on Ti6Al4V titanium alloys, thus boosting their corrosion resistance properties. The nitriding process of Ti6Al4V titanium alloys was conducted in ammonia at 510 degrees Celsius for 0, 1, 2, and 4 hours. High-resolution transmission electron microscopy, atomic force microscopy, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were utilized to characterize the microstructure and phase composition of the Ti-N nitriding layer. The modified layer's composition was found to consist of TiN, Ti2N, and -Ti(N) phases. Mechanical grinding and polishing of the nitrided 4-hour samples was carried out to reveal the varied surfaces of the Ti2N and -Ti (N) phases, enabling a study of their corrosion properties. Comparative biology Electrochemical impedance spectroscopy and potentiodynamic polarization measurements in Hank's solution were employed to assess the corrosion resistance of titanium nitride layers in a simulated human environment. The impact of the Ti-N nitriding layer's microstructure on its ability to resist corrosion was reviewed. The medical applicability of Ti6Al4V titanium alloy is greatly expanded by the Ti-N nitriding layer, which confers improved corrosion resistance.